monensin and Weight-Gain

A meta-analysis of the impact of monensin on growing and finishing beef cattle was conducted after a search of the literature. A total of 40 peer-reviewed articles and 24 additional trial reports with monensin feeding in beef cattle were selected, after meeting apriori quality criteria. Data for each trial were extracted and analyzed using meta-analysis software in STATA. Estimated effect size of monensin was calculated for feed efficiency (FE), ADG, and DMI. Monensin use in growing and finishing beef cattle reduced DMI (P < 0.001) and improved both ADG (P < 0.001) and FE (P < 0.001). The average concentration of monensin in feed across studies was 28.1 mg/kg feed (100% DM) and this resulted in approximately a 6.4% (but only 2.5 to 3.5% in the last 2 decades) increase in FE, 3% decrease in DMI, and 2.5% increase in ADG. All 3 outcomes displayed moderate and significant heterogeneity of monensin response (I(2), which is a measure of variation beyond chance, = 29% for FE, 42% for DMI, and 23% for ADG); therefore, random effects models were used for those outcomes. There were no single influential studies that overweighted the findings for any outcome. Meta-regression analysis of the effect sizes obtained from these data showed that dietary factors, dose, and study design were influential in modifying effect size of monensin treatment. Use of corn silage in the diet influenced the effect size of monensin for DMI and FE, with diets containing corn silage resulting in a greater improvement in FE and a larger effect on reducing DMI. Studies conducted to assess multiple doses of monensin showed similar effects to the use of corn silage in the diet. Studies conducted in the United States or with higher ADG in control animals (>1.17 kg/d) showed less effect of monensin on ADG. Pen-level studies showed a greater monensin increase on ADG than did those conducted on individual animals. Linear effect of monensin dose was observed for FE, DMI, and ADG outcomes, with greater effects on improving FE and reducing DMI with larger doses of monensin but lesser improvement in ADG with increasing dose. These findings confirm that monensin improves FE in growing and finishing beef cattle, and that this effect is linear with dose.

Topics: Animal Feed; Animals; Cattle; Diet; Feeding Behavior; Monensin; Proton Ionophores; Time Factors; Weight Gain

Murrah buffalo heifers (live weight 135 ± 17 kg) were fed a total mixed ration without supplementation (CON), or supplemented with sodium monensin (MON; Rumensin® 200, Elanco Animal Health, Brazil) @ 0.6 mg/kg of body weight for 90 days. Nutrient digestibility and nitrogen retention were estimated during the mid-experiment, and enteric methane production was measured by sulphur hexafluoride tracer technique for consecutive-5 days after the digestion trial. The dry matter (DM) and nutrient intake were not affected but DM intake expressed as percent of body weight was decreased by monensin supplementation (3 vs 2.7% for CON and MON, respectively). The crude protein digestibility was higher for MON whereas, digestibility of other nutrients was not affected. Nitrogen retention (+ 4.59 g/day) and daily body weight gain (+ 56 g/day) were greater for MON-fed heifers without any significant effect on nitrogen intake and nitrogen excretion through faeces and urine. Daily enteric methane production was reduced by 12.61% but the treatments did not differ significantly. Methane emission expressed as gram per unit of DM, organic matter and digestible DM intake was lower for MON than CON and methane conversion rate (Ym) % of GE and ME intake was also decreased by 8-9%. On day 60, blood glucose level was increased and urea nitrogen was decreased in MON-fed heifers. This study indicated that monensin supplementation at 0.6 mg/kg body weight in growing heifers improved daily gain and feed efficiency while it reduced enteric methane production which can reduce feedlot time and consequent life time CH

Topics: Animal Feed; Animals; Antiprotozoal Agents; Buffaloes; Cattle; Diet; Dietary Supplements; Digestion; Energy Intake; Feces; Female; Methane; Monensin; Nitrogen; Nutrients; Weight Gain

The objectives of this study were to examine the effects of feedlot production systems with and without the use of a β-adrenergic agonist compared to an all-natural production program on feedlot performance and carcass characteristics. Crossbred beef steers ( = 336; initial BW = 379 ± 8 kg) were randomized to 1 of 3 treatments in a randomized complete block design (RCBD; 14 steers/pen; 8 pens/treatment). Treatments consisted of an all-natural treatment (NAT), a conventional treatment (CONV), and a conventional treatment with a β-agonist (CONV-Z). All treatments were fed the same basal diet with NAT cattle receiving no growth promoting technologies. The CONV and CONV-Z cattle were implanted with 40 mg of estradiol and 200 mg of trenbolone acetate (TBA) on d 0 and were fed 33 and 9 mg/kg of monensin and tylosin daily, respectively. The CONV-Z cattle were fed zilpaterol hydrochloride (ZH) at 6.76 mg/kg (90% DM basis) for the last 20 days on feed (DOF) There was no effect of treatment on DMI ( = 0.83); however, CONV-Z steers gained 3.8% faster (1.64 vs. 1.58 kg/d; < 0.01) and were 5.3% more efficient (0.160 vs. 0.152; < 0.01) than CONV steers, and CONV steers gained 32.8% faster (1.58 vs. 1.19 kg/d; < 0.01) and were 26.7% more efficient (0.152 vs. 0.120; < 0.01) than NAT steers. There was a 35.7% improvement in estimated carcass gain (1.29 vs. 0.95 kg/d; < 0.01) and a 32.6% improvement in carcass efficiency (0.126 vs. 0.095; < 0.01) for CONV-Z steers compared to NAT steers. Hot carcass weight was increased by 8 kg for CONV-Z steers compared to CONV steers (394 vs. 386 kg; = 0.05) and 46 kg compared to NAT steers (394 vs. 348 kg; < 0.01). Longissimus muscle area was increased by 3.6 cm for CONV-Z steers compared to CONV steers (92.29 vs. 88.67 cm; = 0.02) and 12.1 cm for CONV-Z steers compared to NAT steers (92.29 vs. 80.16 cm; < 0.01), resulting in a 9.6% unit increase in USDA yield grade (YG) 1 (15.14 vs. 5.52%; < 0.05) and a 21.6% unit reduction in USDA YG 3 for CONV-Z steers compared to CONV steers (30.70 vs. 52.32%; < 0.05). The CONV-Z steers had a lower marbling score compared to the other treatments (432; 0.01), resulting in an 11.7% unit increase (20.70 vs. 9.03%; < 0.05) in USDA Select carcasses compared to CONV steers. The results of this experiment show that CONV-Z and CONV production results in a significant improvement in feedlot performance and USDA YG compared to NAT.

Topics: Adrenergic Agents; Adrenergic beta-Agonists; Animals; Anti-Bacterial Agents; Body Composition; Cattle; Diet; Estradiol; Hormones; Male; Monensin; Proton Ionophores; Trenbolone Acetate; Trimethylsilyl Compounds; Tylosin; Weight Gain

The objective of this study was to evaluate conventional (CONV) and natural (NAT) beef production systems from annual pasture through finishing through grazing. Beef steers (n=180, initial BW=250±19 kg) were assigned randomly to 2 treatments in the pasture phase. Steers were implanted with 40 mg of trenbolone acetate (TBA), 8 mg estradiol, and 29 mg tylosin tartrate (CONV), or received no implant (NAT). Steers on the 2 treatments grazed wheat or cereal rye for 109 d. Conventional steers had an 18.5% improvement in ADG (1.22 vs. 1.03 kg/d, P<0.01) and a heavier final BW (385 vs. 366 kg, P<0.01) compared with NAT steers. Following the pasture phase, steers (n=160 steers, 5 steers/pen, 8 pens/treatment) were assigned to a 2×2 factorial in the feedlot phase. Production system (NAT vs. CONV) was maintained from the pasture phase, and the second factor was 7 vs. 12% low-quality roughage (DM basis, LOW vs. HIGH). During finishing, CONV steers were given 120 mg of TBA and 24 mg estradiol at processing, fed monensin and tylosin, and fed zilpaterol hydrochloride for the last 20 d of the experiment. There were no program×roughage level interactions (P>0.07). The CONV steers ate 6.9% more feed (11.8 vs. 11.0 kg/d, P<0.01), gained 28.4% faster (1.90 vs. 1.48 kg/d, P<0.01), and were 24.2% more efficient (0.164 vs. 0.132, P<0.01) compared with NAT steers. The LOW steers had greater G:F (0.153 vs. 0.144, P<0.01) compared with HIGH steers. There was a 28.3% improvement in estimated carcass weight gain (1.36 vs. 1.06 kg/d), 18.6% improvement in carcass efficiency (0.115 vs. 0.097, P<0.01), and 21.6% improvement (1.52 vs. 1.25 Mcal/kg, P<0.01) in calculated dietary NEg for CONV compared with NAT steers. Hot carcass weight was increased by 62 kg (424 vs. 362 kg, P<0.01) and LM area was increased by 16.9 cm2 (100.9 vs. 84.0 cm2, P<0.01), decreasing USDA yield grade (YG, 3.09 vs. 3.54, P<0.01) for CONV steers compared with NAT steers. Natural steers had a greater percentage of carcasses in the upper 2/3 of USDA Choice grade (48.7 vs. 18.7%, P<0.01), a greater percentage of YG 4 and 5 carcasses (25.4 vs. 9.3%, P<0.01), and a greater percentage of abscessed livers (39.6 vs. 10.5%, P<0.01) compared with CONV steers. The results show that CONV production results in more rapid and efficient production that resulted in heavier carcasses with superior YG and desirable quality grades with both roughage levels.

Topics: Animal Feed; Animal Husbandry; Animals; Body Composition; Body Weight; Cattle; Estradiol; Male; Meat; Monensin; Random Allocation; Trenbolone Acetate; Trimethylsilyl Compounds; Tylosin; Weight Gain

Forty Angus-cross steers were used to evaluate 5 beef cattle management regimens for their effect on growth performance, carcass characteristics, and cost of production. A 98-d growing phase was incorporated using grass silage with or without growth promotants (trenbolone acetate + estradiol implants, and monensin in the feed) or soybean meal. Dietary treatments in the finishing phase were developed, with or without addition of the same growth promotants, based on exclusive feeding of forages with minimal supplementation or the feeding of barley-based diets. Overall, ADG for animals treated with growth promotants or fed supplemented diets (soybean meal and barley) was increased (P < 0.01) by 25 and 21%, respectively, compared with steers reared on grass silage alone and not treated with growth promotants. Except for HCW (P < 0.01), the use of growth promotants did not affect carcass measurements. Increasing the proportion of barley in the diet of steers finished on forage produced a heavier HCW (P < 0.01) and a greater (P < 0.01) quality grade. Because of their lower HCW and quality grade, cattle targeted to a forage-fed, nonimplanted beef market would need to garner a 16% premium to be economically competitive with cattle finished conventionally.

Topics: Anabolic Agents; Animal Feed; Animal Husbandry; Animal Nutritional Physiological Phenomena; Animals; Body Composition; Cattle; Diet; Dietary Supplements; Estradiol; Glycine max; Hordeum; Ionophores; Male; Meat; Monensin; Poaceae; Silage; Trenbolone Acetate; Weight Gain

Three experiments (Exp.) were conducted to determine the interactive effects of sodium bentonite (NaB) with the efficacy of monensin (MON) or salinomycin (SAL) in coccidiosis-infected chicks. Male broiler chicks 5 to 14 d of age were used, and each treatment was replicated with eight (Exp. 1) or four (Exp. 2 and 3) pens of five chicks each. In Exp. 1, MON (80 ppm), NaB (0.50%), or MON+NaB were fed to uninfected and coccidiosis-infected (5 x 10(5) sporulated Eimeria acervulina oocysts on Day 2 of the Exp.) chicks in a 2 x 2 x 2 factorial arrangement of treatments. Experiment 2 was identical to Exp. 1, but SAL (30 ppm) replaced MON as the anticoccidial additive. In Exp. 3, MON (55 ppm) or SAL (22 ppm) were added individually or with NaB (0.50%) to diets for uninfected or coccidiosis-infected chicks. Coccidial infection reduced (P < 0.01) gain, feed intake, gain:feed, plasma carotenoids, and percentage tibia ash in all experiments. The MON and SAL additions increased these response criteria in infected chicks (coccidiosis by anticoccidial, P < 0.07), except MON did not increase (P > 0.10) feed intake or tibia ash in Exp. 3. In Exp. 3, NaB partially reduced the positive effect of MON on daily gain (NaB by MON, P < 0.03), and of SAL on feed intake (NaB by SAL, P < 0.08). The NaB addition also increased gain:feed (P < 0.08), and the increase was greater in infected chicks (coccidiosis by NaB, P < 0.08). Also in Exp. 3, SAL increased feed intake more in chicks not fed NaB than in chicks fed NaB (SAL by NaB, P < 0.08). Dietary NaB (0.5%) may reduce the efficacy of MON and SAL in coccidiosis-infected chicks when these additives are added at less than recommended levels.

Topics: Animals; Bentonite; Carotenoids; Chickens; Coccidiosis; Coccidiostats; Diet; Drug Interactions; Eating; Male; Monensin; Poultry Diseases; Pyrans; Tibia; Weight Gain

Anticoccidial efficacy of a drug combination monensin at 8 p.p.m. plus the new antioxidant duokvin at 120 p.p.m. in the feed was compared with that of monensin alone at the recommended level of 100 p.p.m. against a field isolate of the coccidium Eimeria acervulina Tyzzer, 1929 in a battery study. Both monensin and monensin duokvin combination were effective against E. acervulina when judged by weight gain, feed conversion and faecal scores. There was no significant difference in the chemoprophylactic activity of either treatments. Neither monensin at 100 p.p.m. nor the combination proved effective in terms of oocyst production. In accordance with the earlier findings with E. tenella, the combination seems appropriate for field trials.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Combinations; Eimeria; Feces; Monensin; Poultry Diseases; Quinolines; Weight Gain

Coccidiosis is a poultry disease that occurs worldwide and is caused by Eimeria species. The infection is associated with reduced feed efficiency, body weight gain, and egg production. This study aimed to investigate the current status of coccidiosis and anticoccidial resistance to anticoccidial drugs used as part of control strategies for this disease in Korean chicken farms.. An overall prevalence of 75% (291/388) was found. Positive farms contained several Eimeria species (mean = 4.2). Of the positive samples, E. acervulina (98.6%), E. maxima (84.8%), and E. tenella (82.8%) were the most prevalent species. Compared with cage-fed chickens, broilers and native chickens reared in free-range management were more at risk of acquiring an Eimeria infection. Sensitivities to six anticoccidial drugs (clopidol, diclazuril, maduramycin, monensin, salinomycin, and toltrazuril) were tested using nine field samples. Compared with untreated healthy control chickens, the body weight gains of infected chickens and treated/infected chickens were significantly reduced in all groups. Fecal oocyst shedding was significantly reduced in four clopidol-treated/infected groups, three diclazuril-treated/infected groups, two toltrazuril-treated/infected groups, one monensin-treated/infected group, and one salinomycin-treated/infected group, compared with the respective untreated/infected control groups. Intestinal lesion scores were also reduced in three clopidol-treated/infected groups, one monensin-treated/infected group, and one toltrazuril-treated/infected group. However, an overall assessment using the anticoccidial index, percent optimum anticoccidial activity, relative oocyst production, and reduced lesion score index found that all field samples had strong resistance to all tested anticoccidial drugs.. The results of this large-scale epidemiological investigation and anticoccidial sensitivity testing showed a high prevalence of coccidiosis and the presence of severe drug resistant Eimeria species in the field. These findings will be useful for optimizing the control of coccidiosis in the poultry industry.

Topics: Animals; Chickens; Clopidol; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria; Farms; Monensin; Oocysts; Poultry Diseases; Republic of Korea; Weight Gain

The aim of this study was to describe energy partitioning in dairy crossbreed bulls fed tropical forage-based diets supplemented with different additives. Twenty F1 crossbred bulls (Holstein x Gyr) with initial and final live weight (LW) averages of 190 ± 17 and 275 ± 20 kg were fed sorghum (Sorghum bicolour) and Tanzania grass (Panicum maximum cv. Tanzania) silage (70:30 DM basis) with supplemented concentrate at a forage to concentrate ratio of 50:50. The bulls were allocated to four treatment: control groups (without additives), monensin [22 mg/kg monensin dry matter (DM)] (M), virginiamycin (30 mg/kg virginiamycin DM) (V), and combination (22 mg/kg DM of monensin and 30 mg/kg DM of virginiamycin) (MV), in a completely randomised design. The intake of gross energy (GE, MJ/d), digestible energy (DE, MJ/d), metabolizable energy (ME, MJ/d), as well as energy losses in the form of faeces, urine, methane, heat production (HE), and retained energy (RE) were measured. Faecal output was measured in apparent digestibility trial. Right after the apparent digestibility trial, urine samples were collected in order to estimate the daily urinary production of the animals. Heat and methane production were measured in an open circuit respirometry chamber. The intake of GE, DE, and ME of the animals receiving monensin and virginiamycin alone or in combination (MV) showed no differences (P>0.05) from the control treatment. However, the MV treatment reduced (P<0.05) the methane production (5.44 MJ/d) compared to the control group (7.33 MJ/d), expressed in MJ per day, but not when expressed related to gross energy intake (GEI) (CH4, % GEI) (P = 0.34). Virginiamycin and monensin alone or in combination did not change (P>0.05) the utilization efficiency of ME for weight gain, RE and net gain energy. This study showed that for cattle fed tropical forages, the combination of virginiamycin and monensin as feed additives affected their energy metabolism by a reduction in the energy lost as methane.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Cattle; Diet; Energy Intake; Energy Metabolism; Male; Monensin; Panicum; Sorghum; Virginiamycin; Weight Gain

This study evaluated the effect of increasing levels of monensin sodium (MON) in diets with virginiamycin (VM) on the finishing of feedlot cattle. Two hundred and eighty intact male Nellore cattle (348 ± 32 kg body weight, 22 months) received one of the following five diets: control diet (without additives); diet containing VM (25 mg per kg dry matter) combined with 0 (MON0), 10 (MON10), 20 (MON20) or 30 (MON30) mg MON per kg dry matter. During adaptation (28 days), the MON0 diet increased dietary net energy for maintenance and gain compared to the control diet (P = 0.04). The combination of additives linearly reduced dry matter intake, body weight and average daily gain (P < 0.01). Considering the total study period (110 days), there was a trend of greater net energy intake for maintenance (P = 0.09) and hot carcass weight (P = 0.06) for animals fed MON0 compared to the control diet. The combination of additives linearly reduced dry matter intake (P = 0.04) and linearly increased gain : feed and dietary net energy for maintenance and gain (P < 0.01). The combination of VM with MON at a dose of 30 mg/kg dry matter is recommended for Nellore feedlot cattle because it improves the efficiency of energy utilization.

Topics: Animals; Body Weight; Cattle; Diet; Dose-Response Relationship, Drug; Eating; Energy Intake; Energy Metabolism; Male; Monensin; Virginiamycin; Weight Gain

A protective digestive microflora helps prevent and reduce broiler infection and colonization by enteropathogens. In the current experiment, broilers fed diets supplemented with probiotics and essential oil (EO) blends were infected with a standard mixed Eimeria spp. to determine effects of performance enhancers on ileal and cecal microbial communities (MCs). Eight treatment groups included four controls (uninfected-unmedicated [UU], unmedicated-infected, the antibiotic BMD plus the ionophore Coban as positive control, and the ionophore as negative control), and four treatments (probiotics BC-30 and Calsporin; and EO, Crina Poultry Plus, and Crina PoultryAF). Day-old broilers were raised to 14 days in floor pens on used litter and then were moved to Petersime batteries and inoculated at 15 days with mixed Eimeria spp. Ileal and cecal samples were collected at 14 days and 7 days postinfection. Digesta DNA was subjected to pyrosequencing for sequencing of individual cecal bacteria and denaturing gradient gel electrophoresis (DGGE) for determination of changes in ileal and cecal MC according to percentage similarity coefficient (%SC). Pyrosequencing is very sensitive detecting shifts in individual bacterial sequences, whereas DGGE is able to detect gross shifts in entire MC. These combined techniques offer versatility toward identifying feed additive and mild Eimeria infection modulation of broiler MC. Pyrosequencing detected 147 bacterial species sequences. Additionally, pyrosequencing revealed the presence of relatively low levels of the potential human enteropathogens Campylobacter sp. and four Shigella spp. as well as the potential poultry pathogen Clostridiun perfringens. Pre- and postinfection changes in ileal (56%SC) and cecal (78.5%SC) DGGE profiles resulted from the coccidia infection and with increased broiler age. Probiotics and EO changed MC from those seen in UU ilea and ceca. Results potentially reflect the performance enhancement above expectations in comparison to broilers not given the probiotics or the specific EO blends as feed supplements.

Topics: Animal Feed; Animals; Bacteria; Biodiversity; Cecum; Chickens; Coccidiosis; Coinfection; Denaturing Gradient Gel Electrophoresis; DNA, Bacterial; DNA, Ribosomal; Eimeria; Ileum; Male; Monensin; Oils, Volatile; Poultry Diseases; Probiotics; Proton Ionophores; Random Allocation; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Weight Gain

To determine the prevalence of subacute rumen acidosis (SARA) in beef cattle grazing lush pasture and the effect of monensin on reducing SARA and improving animal performance.. Commercial Angus and Murray Grey steers received a monensin slow-release capsule (n = 19) or remained untreated (n = 19). Cattle grazed an oats crop or tetraploid ryegrass pasture for a total of 91 days. Rumen fluid pH, volatile fatty acids (VFA) and lactic acid concentrations and body weight data were collected prior to treatment and again 28, 56 and 91 days after treatment. Changes in measures over time were analysed using mixed model repeated measures analysis. Differences in average daily gain between treatment groups were determined.. The prevalence of SARA was low during the study, with only one animal satisfying criteria for SARA at one time point. Cattle treated with monensin capsules were 11.9 kg heavier at the completion of the study compared with untreated controls (414.5 ± 3.88 kg vs 402.6 ± 4.03 kg, P = 0.04). Rumen VFA and L- and D-lactate levels did not differ between cattle treated with monensin and untreated cattle. However, the ratio of propionate to acetate plus two times butyrate was higher (P < 0.001) when cattle were treated with monensin.. Subacute rumen acidosis was not consistently detected under the conditions of the study. The higher body weight of cattle treated with monensin may have been due to improved energy utilisation of the pasture, indicated by increased propionate proportions in the rumen, rather than prevention of SARA.

Topics: Acidosis; Animal Feed; Animals; Cattle; Fermentation; Male; Monensin; Poaceae; Random Allocation; Rumen; Weight Gain

Two trials were conducted to evaluate the influence of virginiamycin supplementation on growth performance and digestive function. In trial 1, 144 Holstein steer calves (119 kg of initial BW) were used in a 340-d trial. Treatments were (DM basis) 1) control (no antibiotic); 2) 16 mg/kg of virginiamycin; 3) 22.5 mg/kg of virginiamycin; and 4) 28 mg/kg of monensin. Calves received a steam-flaked corn-based growing diet for the first 112 d and thereafter were fed a finishing diet from d 112 until slaughter. Steers were divided into 2 BW groups (lighter-half and heavier-half), and assigned within groups to 24 pens (6 steers/pen). Virginiamycin did not affect (P > 0.20) ADG, but increased 340-d G:F (linear; P = 0.02) and dietary NE (linear; P = 0.04). Improvements in dietary NE were most pronounced during the final 116 d of the feeding period (linear; P = 0.04) that comprised the hot summer months (June through September). Monensin did not affect (P > 0.20) growth performance or dietary NE. Although average initial BW of the lighter-half and heavier-half BW groups differed by only 4 kg, the heavier BW group had greater HCW (13 kg, P = 0.02), LM area (5.4%, P = 0.01), ADG (4.3%, P = 0.02), G:F (2.3%, P = 0.08), and dietary NE (3.2%. P = 0.01) than the lighter BW group. In trial 2, 4 Holstein steers (269 +/- 3.5 kg) with cannulas in the rumen and proximal duodenum were used in a 4 x 4 Latin square design to evaluate treatment effects on digestion. Virginiamycin did not affect (P > 0.20) ruminal digestion of OM, NDF, starch, and N, and microbial efficiency, but tended to linearly increase (P = 0.09) ruminal N efficiency (nonammonia N flow to the small intestine/N intake). Likewise, virginiamycin did not affect (P > 0.20) postruminal or total tract digestion of OM, starch, NDF, and N. Compared with the control diet, monensin depressed total tract digestion of OM (4.2%, P = 0.03) and NDF (29.5%, P = 0.02). There were no treatment effects (P > 0.20) on ruminal pH, or ruminal lactate and total VFA molar concentration. Virginiamycin increased ruminal molar proportion of acetate (quadratic; P = 0.04) and estimated methane production (quadratic; P = 0.07), and decreased propionate molar proportion (quadratic; P = 0.09). Monensin did not affect (P > 0.20) ruminal VFA molar proportions or estimated methane production. We concluded that virginiamycin supplementation can enhance feedlot growth-performance and dietary energetic efficiency of calf-fed Holstein steers.

Topics: Animals; Anti-Bacterial Agents; Cattle; Diet; Digestion; Duodenum; Energy Metabolism; Food Additives; Male; Monensin; Rumen; Virginiamycin; Weight Gain

A 2-yr study was conducted during the 2004 to 2005 (YR1) and 2005 to 2006 (YR2) winter wheat grazing seasons to determine the effects of supplementation strategies and delivery methods on supplement intake and growth performance of grazing steers (YR1, n = 253, initial BW 255 +/- 25 kg; YR2, n = 116, initial BW 287 +/- 14 kg). The 5 treatments were as follows: 1) negative control (NC), no supplemental nutrients; 2) free-choice, nonmedicated mineral (MIN); 3) free-choice, medicated mineral with 1,785 mg of monensin/kg of mineral mixture (RMIN); 4) RMIN and soybean hulls (SH-RMIN); and 5) a soybean hull-based energy supplement containing 165 mg of monensin/kg (GRNGOLD). Energy supplements were hand-fed on alternate days (average daily intake = 0.91 kg/steer). Inclusion of monensin in the free-choice mineral mixture decreased intake of the mineral mixture by 63% in YR1 and 55% in YR2 when no other supplement was offered. Consumption of RMIN provided from 129 to 161 mg of monensin/steer on average, whereas GRNGOLD provided 150 mg of monensin/d. Compared with NC, MIN did not affect ADG in YR1 (P = 0.38) but increased (P = 0.01) ADG by 0.22 kg/steer in YR2. Conversely, ADG of RMIN steers was greater (P = 0.03) than that of MIN steers during YR1 (0.72 vs. 0.55 kg/steer) but not different (P = 0.35) in YR2. Providing supplemental energy increased ADG by 0.13 kg/steer (0.85 vs. 0.72 +/- 0.053) in YR1 compared with RMIN, but no increase in ADG was observed in YR2. No difference (P > 0.24) was observed in ADG between SH-RMIN and GRNGOLD in either year. Conversion of the energy supplements (kg of as-fed supplement divided by kg of additional ADG) was excellent in YR1, resulting in 1 kg of BW gain for each 3.1 kg of supplement consumed. However, due to smaller increases in ADG with the energy and monensin supplements in YR2, supplement conversion for YR2 averaged 17.6. The absence of a difference (P > 0.24) in ADG between steers that received SH-RMIN and GRNGOLD suggests that the method of delivery (separate packages vs. a single package) for energy, monensin, and mineral supplementation is not important.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Cattle; Dietary Supplements; Energy Intake; Male; Minerals; Monensin; Poaceae; Random Allocation; Seasons; Triticum; Weight Gain

Eighty steers with a mean body weight of 319 kg were used in a study to evaluate the effect of a growth-promoting implant (trenbolone acetate plus estradiol benzoate), monensin, and oxytetracycline on the steer performance and shedding of some foodborne pathogens. The steers were allotted to one of eight treatment combinations according to a randomized complete block design with 16 pens of five animals. Rectal fecal samples were collected before treatment commenced and over a period of more than 24 weeks to study the influence of treatments on the intestinal microbiology of the animals. Results supported the beneficial effect of the hormonal implant on the performance of feedlot steers (average daily gain, feed efficiency, and fat thickness), on carcass characteristics (hot carcass weight, lean yield), and economic value of the carcasses (P < 0.01). The levels of Escherichia coli in feces were not affected by treatments but remained high throughout the study period. Antibiotic-resistant isolates of E. coli were more frequently found as the study progressed but were not associated with any specific treatment. Also independently of treatment, we observed a reduction over time in the shedding of Campylobacter and Yersinia during the feeding period, whereas the shedding of Enterococcus was increased. The results of this study confirmed the beneficial economic effect of growth-promoting agents in beef production and showed that the agents tested did not specifically affect the overall microbial evolution of the animal gut. However, the study also showed, independently of the growth promoter used, the shedding of Campylobacter, Yersinia, and antibiotic-resistant E. coli in the feedlot environment. These bacteria also may be found in the colonic tissue of steers at slaughter and might be a source of carcasses contamination.

Topics: Anabolic Agents; Animals; Anti-Bacterial Agents; Campylobacter; Cattle; Colon; Colony Count, Microbial; Cost-Benefit Analysis; Eating; Escherichia coli; Escherichia coli O157; Estradiol; Feces; Male; Microbial Sensitivity Tests; Monensin; Oxytetracycline; Random Allocation; Trenbolone Acetate; Weight Gain; Yersinia

Sixty Angus-cross steers were used to compare the effects of recycled poultry bedding (RPB) stacking method and the inclusion of monensin in growing diets on performance. Steers were individually fed balanced, growing diets for a period of 84 d. The diets were control (CON), CON + monensin (CON+M), deep-stacked RPB (DS), DS+M, shallow-stacked RPB (SS), and SS+M. The CON diets contained corn, soybean meal, corn silage, and cottonseed hulls. In the RPB diets, 35% of the silage, cottonseed hulls, and soybean meal was replaced with RPB (as-fed basis). At the end of the growing period, 30 steers, representing all treatment groups, had liver biopsies for trace mineral analysis and ruminal fluid samples to assess pH, VFA, and ammonia concentrations. All steers had blood samples drawn at the end of the growing period for analysis of Se and urea N. Steers were transported 466.6 km to simulate shipping stress and started on a finishing diet for a 120-d period. Intake, ADG, and G:F were monitored throughout the trial. Steers fed CON diets had higher ADG, DMI, and G:F than SS, and higher ADG and G:F than DS (P < 0.05) during the growing period. Steers fed DS diets had higher DMI than SS (P < 0.05) during the growing period. Inclusion of monensin in the growing diets increased G:F and decreased DMI (P < 0.05). Steers from the RPB treatments started the finishing period at lighter BW than steers fed CON diets (P < 0.05). During the finishing period, steers fed SS diets had higher DMI than steers fed CON diets (P < 0.06), whereas steers fed DS diets were intermediate. At slaughter, steers fed CON diets had higher hot carcass weights and quality grades than steers fed SS diets (P < 0.07), whereas steers fed DS diets were intermediate. Results indicate that steers fed RPB consumed it better when processed by deep stacking before consumption, that carryover effects of RPB into the finishing phase were minimal, and inclusion of monensin did not affect consumption of RPB diets.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Body Composition; Body Constitution; Cattle; Conservation of Natural Resources; Eating; Floors and Floorcoverings; Liver; Male; Monensin; Poultry; Random Allocation; Rumen; Transportation; Weight Gain

Two commercial feedlot experiments and a metabolism study were conducted to evaluate the effects of monensin concentrations and bunk management strategies on performance, feed intake, and ruminal metabolism. In the feedlot experiments, 1,793 and 1,615 steers were used in Exp. 1 and 2, respectively, in 18 pens for each experiment (six pens/treatment). Three treatments were evaluated: 1) ad libitum bunk management with 28.6 mg/kg monensin and clean bunk management strategies with either 2) 28.6 or 3) 36.3 mg/kg monensin. In both experiments, 54 to 59% of the clean bunk pens were clean at targeted clean time, or 2200, compared with 24 to 28% of the ad libitum pens. However, only 13% of the pens were clean by 2000 in Exp. 1 (summer), whereas 44% of the pens in Exp. 2 (winter) were clean by 2000. In Exp. 1, bunk management and monensin concentration did not affect carcass-adjusted performance. In Exp. 2, steers fed ad libitum had greater DMI (P < 0.01) and carcass-adjusted ADG (P < 0.01) but feed efficiency (P > 0.13) similar to that of clean bunk-fed steers. Monensin concentration had no effect on carcass-adjusted performance (P > 0.20) in either experiment. A metabolism experiment was conducted with eight fistulated steers in a replicated 4 x 4 Latin square acidosis challenge experiment. An acidosis challenge was imposed by feeding 125% of the previous day's DMI, 4 h later than normal. Treatments consisted of monensin concentrations (mg/kg) of 0, 36.7, 48.9, or 36.7 until challenged and switched to 48.9 on the challenge day and 4 d following. Each replicate of the Latin square was managed with separate bunk management strategies (clean bunk or ad libitum). Feeding any concentration of monensin increased number of meals and decreased DMI rate (%/h) (P < 0.12) for the 4 d following the acidosis challenge. Meal size, pH change, and pH variance were lower (P < 0.10) for steers fed monensin with clean bunk management. However, no monensin effect was observed for steers fed ad libitum. Bunk management strategy has the potential to decrease DMI and ADG when steers managed on a clean bunk program are restricted relative to traditional, ad libitum bunk programs. Monensin helps control intake patterns for individuals, but increasing concentration above currently approved levels in this study seemed to have little effect.

Topics: Acidosis; Animal Feed; Animal Husbandry; Animals; Cattle; Digestion; Dose-Response Relationship, Drug; Eating; Hydrogen-Ion Concentration; Ionophores; Male; Monensin; Random Allocation; Rumen; Seasons; Weight Gain

A live attenuated anticoccidial vaccine (Paracox) was compared with a nicarbazin-monensin anticoccidial drug shuttle programme in three crops of Italian broilers, comprising a total of 290,405 chickens. All birds received the antibiotic growth promoter avilamycin. No coccidiosis was evident during the trials, but the occurrence of oocysts in the litter demonstrated that a natural challenge was present. Vaccinated birds consistently performed at least as well as those treated with the anticoccidial drug shuttle. The final mean weights of vaccinated birds were significantly greater (P < 0.001) than those of birds treated with anticoccidial drugs, both for females at 36/37 days and males at 56 days. Feed conversion ratios, total mortality including culls, the proportion of rejects at the processing plant, and the moisture content of the litter were not significantly different between the two control methods. Growth curves showed that there was no post-vaccinal growth check in the vaccinated birds and no intolerance of the anticoccidial drug treatment. There was no overall seasonal effect, regardless of treatment, on the performance of the three crops reared from November 1997 to July 1998. These findings suggest that the use of this vaccine is likely to enable the replacement of anticoccidial drug shuttle programmes in broilers reared under conditions similar to those used in these Italian flocks.

Topics: Animal Feed; Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Female; Italy; Male; Monensin; Nicarbazin; Oligosaccharides; Oocysts; Poultry Diseases; Protozoan Vaccines; Vaccination; Vaccines, Attenuated; Weight Gain

We conducted two experiments to evaluate the effect of the ionophore laidlomycin propionate (LP) on steer performance and ruminal N metabolism. Experiment 1 was a 91-d growth study evaluating the growth and ruminal characteristics of steer calves consuming supplemental LP. Steers (n = 96; 255 +/- 3 kg; four steers/pen; six pens/treatment) were used in a randomized complete block design with a 2 x 2 factorial arrangement of treatments consisting of two levels of dietary CP (formulated to be 10.5 and 12.5% of DM) with and without LP (11 mg/kg diet DM). Ruminal fluid was collected via stomach tube on d 91 from one steer randomly selected from each pen. No CP x LP interactions were observed with performance data (P > .64). Final weight and total gain were greater (P < .07) for 12.5% CP and LP compared with 10.5% CP and control steers, respectively. Also, DMI was increased (P = .08) with 12.5% CP but not with LP supplementation (P = .36). In addition, ADG and gain:feed ratio were greater (P < .03) for both 12.5% CP and supplemental LP. Ruminal NH3 N concentration was greater (P < .09) with 12.5% CP and LP. Total VFA concentration and molar proportion of acetate were not affected by treatment (P > .11). However, propionate concentration was increased (P < .09) with 12.5% CP and LP, and acetate:propionate was lower (P = .02) with LP supplementation. In Exp. 2, six steers were used in a replicated 3 x 3 Latin square design to compare ruminal fermentation and protein degradation in steers without ionophore feeding or adapted to LP or monensin. In vitro deamination of amino acids by adapted ruminal microbes was also assessed. Ionophore supplementation decreased (P = .07) ruminal NH3 N concentration compared with control steers, and LP increased (P = .02) ruminal NH3 N compared with monensin. Molar proportion of acetate was decreased (P = .02) and propionate increased (P = .01) with ionophore treatment. Consequently, ionophore supplementation depressed the acetate:propionate ratio (P = .01). In situ degradation rate of soybean meal (SBM) CP was greater (P = .09) with ionophore treatment, but estimates of SBM undegradable intake protein were not altered by treatment (P > .25). Microbial specific activity of net NH3 N release and alpha-amino N degradation were decreased (P < .04) with ionophores. Based on this study, LP and monensin did not affect the extent of ruminal degradation of SBM CP but decreased amino acid deamination.

Topics: Animal Feed; Animals; Cattle; Dietary Proteins; Male; Monensin; Nitrogen; Rumen; Weight Gain

Effects of the administration of monensin via concentrates to dairy cows were studied in two trials. In one trial, 64 Holstein cows were assigned to four groups that received 0, 150, 300, or 450 mg/d of monensin from 5 to 24 wk postpartum. Milk production tended to increase (4.0, 3.3, and 5.4%, respectively) for the three groups of treated cows. Fat content was decreased by 0.09, 1.89, and 4.09 g/kg, respectively, for these same three groups. The effect on protein content was small and nonsignificant. Feed intake was reduced in treated cows, although not significantly, and feed efficiency was improved by monensin. In a confirmatory trial, 58 Holstein and 22 Jersey cows were allocated either to a control group or to a treatment group that received 300 mg/d of monensin from 5 to 36 wk postpartum during the first lactation and from 2 wk before calving to 36 wk postpartum during a subsequent lactation. During the first lactation, cows in the treatment group showed a 7% increase in milk production, a relative decrease (1.4 g/kg) in milk fat content, and equal protein content compared with cows in the control group. Body weight gain and body condition scores near the end of the treatment period were higher for cows in the treatment group. A decrease in blood ketone concentrations was found between 7 and 56 d of lactation. Treatment effects on milk production differed between breeds and within genetic lines. Jersey cows were less responsive than were Holstein cows, and Holstein cows with a high ratio of breeding values for protein and fat showed larger milk production responses. Results from the second lactation showed similar differences between the two groups as did those from the first lactation.

Topics: 3-Hydroxybutyric Acid; Animals; Blood Glucose; Body Composition; Cattle; Female; Hydroxybutyrates; Ionophores; Lactation; Lactose; Lipids; Milk; Milk Proteins; Monensin; Species Specificity; Weight Gain

We used 216 Holstein steers (151 kg) in a 262-d trial to evaluate the influence of dietary magnesium level (.19, .25, and .32%) and laidlomycin propionate (LP; 0 vs 11 ppm, air-dry basis) on growth performance and NE value of the diet. During the initial 112 d of the trial, LP increased (P < .01) ADG (6.3%) and feed efficiency (4.2%). From d 112 until slaughter, LP increased (P < .05) ADG (9.7%) and feed efficiency (4.5%). Across the 262-d feeding period, LP supplementation enhanced (P < .01) ADG (8.9%) and feed efficiency (6.3%). There was an interaction (P < .05) between dietary Mg and LP on NE value of the diet. The enhancement in NE value of the diets owing to LP with .19, .25, and .32% dietary Mg were .5, 3.0, and 5.9%, respectively. Six Holstein steers (302 kg) were used in a 6 x 6 Latin square experiment to evaluate treatment effects on characteristics of ruminal and total tract digestion. There were no treatment interactions (P > .10) on site and extent of digestion of OM, starch, and N. Supplemental Mg increased (quadratic effect, P < .10) ruminal OM digestion. Neither LP nor dietary Mg level affected (P > .10) ruminal digestion of starch and feed N. Supplemental LP decreased (15%, P < .05) ruminal microbial efficiency. Total tract digestion of OM and N increased (linear effect, P < .01) with increasing dietary Mg level. There were interactions between LP and dietary Mg level on ruminal soluble-Mg concentration (linear effect, P < .01) and Mg absorption (quadratic effect, P < .05). Apparent total tract Mg digestion increased owing to LP (P < .01) and dietary Mg level (linear effect, P < .01). There were no treatment effects (P > .10) on ruminal pH. Dietary Mg level did not influence (P > .10) ruminal VFA concentrations or molar proportions. Supplemental LP increased (14%; P < .10) total ruminal VFA concentration but did not affect (P > .10) VFA molar proportions. We conclude that LP will increase daily weight gain and feed efficiency of calf-fed Holstein steers and that this response may be enhanced by increasing dietary Mg level.

Topics: Adipose Tissue; Animal Feed; Animals; Cattle; Cattle Diseases; Diet; Dietary Supplements; Digestion; Eating; Liver Abscess; Magnesium; Male; Meat; Monensin; Rumen; Weight Gain

The effectiveness of Triancinolone as a protector against coccidiosis in broilers was tested in a random design experiment. Cobb x Cobb one-day old chicken were assigned to the treatments: T1: no medication-no inoculation; T2: no medication-inoculation; T3: Triancinolone-inoculation; T4: Sodic Monensin-inoculation; and T5: Sodic Salinomycin-inoculation. The inoculation was accomplished with 10,000 oocysts of Eimeria tenella and 40,000 of intestinal Eimerias. The results of the intestinal damage degree showed that T3 (60.6%) and T4 (63.6%) were better to control coccidias in relation to T5 (96.9%) and T2 (100%). The oocysts number in feces (number/g) showed the best effectiveness for T3 (4,300) comparing with T4 (126,900), T5 (98,100), and T2 (382,000). These results emphasize the effective action mechanism of Triancinolone to interfere with the biological cycle of coccidias. The feed conversion was better (P < 0.05) in the groups that received the drugs (T3, T4, and T5) comparing with T2. This fact showed the adverse effect that coccidiosis cause on the broiler performance behavior. Triancinolone showed the best action effectiveness on the control of coccidiosis.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Evaluation Studies as Topic; Monensin; Pyrans; Triamcinolone; Weight Gain

Three experiments (Exp.) were conducted to evaluate the interactive effects of dietary betaine (BET) and monensin (MON) in uninfected or Eimeria acervulina-infected chicks. The treatments were replicated with six (Exp. 1) or five (Exp. 2 and 3) pens of five chicks each. The experimental periods lasted 9 (Exp. 1 and 2) or 10 (Exp. 3) d each and the coccidiosis infections were established on Day 2 (Exp. 1 and 2) or Day 3 (Exp. 3) of the experiment. Average initial weight of the chicks was 101, 73, and 68 g in Exp. 1 to 3, respectively, and the initial age of the chicks was 5 (Exp. 1) or 4 (Exp. 2 and 3) d. A corn-soybean meal basal diet was used in each experiment. In Exp. 1, the effect of dietary BET (0, 0.1, or 0.5%) in uninfected or coccidiosis-infected (COC; 5 x 10(5) sporulated E. acervulina oocysts) chicks was investigated. In Exp. 2, the interactive effects of BET (0 or 0.1%) and MON (0 or 55 ppm) in uninfected or COC chicks were investigated in a 2 x 2 x 2 factorial arrangement of treatments. Experiment 3 was identical to Exp. 2, except the level of MON was 110 rather than 55 ppm. In Exp. 1, 2, and 3, COC reduced (P < 0.01) gain, feed intake (FI), feed efficiency (GF), and plasma carotenoid concentration (CAR) and increased (P < 0.01) lesion score (LS). In Exp. 1, gain and FI were decreased in uninfected chicks fed 0.1% BET but gain and FI were increased in COC chicks fed 0.1% BET (COC x BET quadratic, P < 0.01). Dietary BET linearly increased (P < 0.05) GF. In Exp. 2 and 3, MON increased (P < 0.01) gain, FI, GF, and CAR and decreased (P < 0.01) LS of COC chicks, but MON had no effect in uninfected chicks (COC x MON, P < 0.01). In Exp. 2, GF was increased more in chicks fed both MON and BET than in chicks fed MON (BET x MON, P < 0.06). In Exp. 3, BET increased GF of uninfected chicks fed MON and of COC chicks not fed MON (COC x BET x MON, P < 0.02). Betaine may have an effect on E. acervulina-infected chicks, but there is no conclusive evidence to indicate that the efficacy of MON is improved when fed in combination with BET.

Topics: Animal Feed; Animals; Betaine; Carotenoids; Chickens; Coccidiosis; Coccidiostats; Diet; Drug Interactions; Drug Therapy, Combination; Eating; Eimeria; Lipotropic Agents; Male; Monensin; Poultry Diseases; Random Allocation; Weight Gain

We conducted two growth trials to evaluate the effects of monensin on amino acid sparing. When Holstein steers were fed a 90% concentrate diet supplemented with soybean meal (13.5% CP), the DMI, ADG, and efficiencies of feed and nitrogen utilization were greater than with urea (P < .10). Monensin improved ADG with both nitrogen supplements (P < .01), but the positive effects of monensin on efficiencies of feed (P = .12) and nitrogen (P = .26) utilization were greater for soybean meal than for urea. Increasing amounts of monensin (0, 11, or 22 mg/kg of DM) caused a linear increase in DMI with urea. Diets with soybean had greater intakes than diets with urea (P < .01); the greatest intake was of a soybean diet with monensin at 11 mg/kg of DM. Holstein steers fed soybean meal at 13.5% CP had lower DMI and greater efficiencies of feed and nitrogen utilization than steers fed 16.7% CP (P < .10). Crude protein level had no effect on ADG (P > .10). Monensin always increased the efficiencies of feed and nitrogen utilization (P < .05), but these trends were greater for diets with 16.7 than for those with 13.5% CP. Overall, monensin decreased DMI (P < .01), but this effect was greater for 16.7% than for 13.5% CP. Because the positive effects of monensin on diet NEg (P = .16) and efficiency of nitrogen utilization (P = .26) were greater for soybean meal than for urea, it seemed that monensin was sparing amino acids.

Topics: Animals; Cattle; Coccidiostats; Diet; Dietary Supplements; Dose-Response Relationship, Drug; Eating; Glycine max; Male; Monensin; Nitrogen; Random Allocation; Urea; Weight Gain

Three experiments were conducted to evaluate elevated dietary NaCl levels as a means of offsetting industry-observed reductions of growth, feed intake, and feed efficiency associated with early (35-d) coccidiostat withdrawal. In the first experiment, monensin (100 ppm) was withdrawn and dietary salt levels of 0.33, 0.48, 0.63, 0.78, or 0.93% provided from 35 to 42 d of age. Experiments 2 and 3 involved lasalocid (110 ppm) withdrawal and slat amounts of 0.33, 0.53, 0.73, or 0.93%. In all studies, a positive control of 0.33% salt and the coccidiostat was also given. Monensin withdrawal reduced body weight gain, which was not overcome by slat addition. Feed efficiency during the 1-wk period was improved to the level of the group receiving continued medication by salt amounts of 0.78% or above. In contrast to industry field observations, removal of lasalocid did not reduce body weight gain, feed intake, or water consumption, and elevation of salt levels resulted in no consistent improvements of weight gain, feed intake, or feed conversion. Water intake increased proportionally as salt concentration increased. Elevated salt levels do not appear to be a reliable means of offsetting reduced performance related to early coccidiostat withdrawal, nor were such performance problems demonstrable for lasalocid in these trials.

Topics: Aging; Animals; Body Weight; Chickens; Coccidiostats; Dose-Response Relationship, Drug; Drinking; Eating; Lasalocid; Monensin; Sodium Chloride, Dietary; Weight Gain

Two experiments were conducted to determine the physical, chemical, and microbial properties of turkey cecal droppings and relate them to intake of common dietary components, namely fat, fiber, and the anticoccidial, monensin. Experiment 1 involved collection and analysis of physical and chemical properties of cecal and regular droppings from commercial turkey flocks. Experiment 2 tested the effect of dietary fat, fiber, and monensin on growth performance and cecal activity in male turkeys. Compared to regular excreta, cecal droppings analyzed in Experiment 1 were higher in viscosity and fat content, and lower in dry matter, nitrogen, and fiber content (P < 0.05). High dietary fiber and fat significantly (P < 0.05) improved growth performance in Experiment 2. Prolonged feeding of monensin significantly (P < 0.05) reduced cecal evacuation. Results of chemical composition showed that higher dietary fat and fiber significantly (P < 0.01) reduced the fat percentage of cecal contents, whereas prolonged feeding of monensin increased the fat in both cecal contents and droppings. There was no significant effect of any of the treatments on pH, viscosity, and microbial counts of cecal contents. There is the need to identify and characterize the compound responsible for the high viscosity of cecal droppings.

Topics: Animals; Body Weight; Cecum; Coccidiostats; Diet; Dietary Fats; Dietary Fiber; Feces; Hydrogen-Ion Concentration; Lipids; Male; Monensin; Nitrogen; Random Allocation; Turkeys; Viscosity; Weight Gain

One growth trial using crossbred beef steers (297 +/- 2 kg, Exp. 1) and one metabolism trial using Holstein steers (405 +/- 14 kg, Exp. 2) were conducted to evaluate effects of ammoniation (3% of hay DM, added as anhydrous NH3) vs urea supplementation with or without monensin supplementation of mature 'Alicia' bermudagrass hay-based diets for steers. Ammoniation (P < .05), but not urea (P = .26) or monensin (P = .70) supplementation, increased ADG in Exp. 1. In Exp. 2 ammoniation increased hay DMI (P < .05), but urea (P = .88) or monensin (P = .16) had no effect. Supplementation with either monensin (P < .05) or urea (P < .05) decreased ruminal total VFA concentrations. Monensin also decreased the ruminal acetate:propionate ratio (P < .001) and increased ruminal pH (P < .05). Addition of urea to the concentrate supplement decreased the rate of concentrate intake. Both the rate (P < .05) and the potential extent (P < .001) of ruminal forage in situ DM and NDF disappearance were increased by ammonia treatment. Dietary interactions (P < .10) were detected between monensin and ammoniation for rate and potential extent of in situ NDF disappearance and between monensin and urea supplementation (P < .05) for ruminal total free amino acid concentrations. Decreased concentrations of VFA and lower forage digestibilities observed with monensin supplementation in Exp. 2 may explain the failure of monensin to affect ADG in Exp. 1.

Topics: Ammonia; Animal Feed; Animals; Cattle; Eating; Fatty Acids, Volatile; Food, Fortified; Hydrogen-Ion Concentration; Male; Monensin; Nitrogen; Poaceae; Rumen; Time Factors; Urea; Weight Gain

The performance of broilers reared in floor pens and given monensin in the feed at 121 ppm was compared with that of birds given no drug. Feed intake and BW gain of medicated birds was significantly lower than that of unmedicated birds from 0 to 22 d of age. Feed intake and feed conversion of medicated birds was significantly reduced, compared with unmedicated birds, from 22 to 53 and 0 to 60 d of age. Total mortality, and mortality due to leg abnormalities from 22 to 53 and 0 to 60 d, was significantly lower in birds given monensin. There was no difference in the incidence of tibial dyschondroplasia (TD) by 60 d. No differences in mortality due to pulmonary hypertension syndrome (PHS) were observed for any age period. Birds removed from pens at 28 d that had received monensin had lower hematocrit and percentage saturation of hemoglobin with oxygen in the blood than unmedicated birds. No differences in these variables were found at 54 d. There were no differences in the right ventricle weight: total ventricular weight ratios or electrocardiogram lead II values at 28 or 54 d. The results indicate that PHS does not occur more frequently in broilers medicated with monensin.

Topics: Animals; Ascites; Chickens; Eating; Food, Fortified; Incidence; Male; Monensin; Poultry Diseases; Weight Gain

A feedlot growth-performance trial and a metabolism trial were conducted to evaluate the interaction of forage level (10 vs 20%) and monensin (0 vs 28 mg/kg, air-dry basis) on utilization of a steam-flaked corn-based finishing diet. There were no treatment interactions (P > .10) on feedlot cattle growth performance or site and extent of digestion of OM, ADF, N, and starch. Monensin supplementation did not influence (P > .10) ADG, DM intake, feed efficiency, estimated NE value of the diet, or ruminal and total tract digestibility of OM, ADF, and starch. Monensin decreased (14.5%, P < .10) passage of microbial N to the small intestine and ruminal digestion of feed N (10.4%, P < .05). Ruminal pH tended to be slightly lower (1.9%, P < .10) with monensin supplementation. Monensin did not affect (P > .10) ruminal molar proportions of acetate and butyrate. There was an interaction between forage level and monensin on ruminal molar proportions of propionate. With the low-forage diet, molar proportions of propionate were 9.4% higher with monensin supplementation. In contrast, with the high-forage diet ruminal molar proportions of propionate were 5.5% lower with supplemental monensin. Monensin did not affect (P > .10) estimates of methane production. Decreasing the forage in the diet from 20 to 10% increased ADG (10.8%, P < .10), feed efficiency (11.6%, P < .01), and diet NEg (11.3%, P < .05). Ruminal digestibility of ADF, OM, and starch were not affected (P > .10) by forage level.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animal Feed; Animals; Cattle; Digestion; Eating; Food, Fortified; Hydrogen-Ion Concentration; Male; Monensin; Random Allocation; Rumen; Weight Gain

Fourteen crossbred beef steers (average initial BW 313 +/- 13.1 kg) fed a 90% concentrate diet (as-fed basis) were used to evaluate effects of ionophores on serum metabolic hormones and clinical chemistry profiles. Treatments were no ionophore (C; four steers), lasalocid (L; 33 mg/kg of diet; five steers), and monensin (33 mg/kg of diet) plus tylosin (11 mg/kg of diet; MT; five steers). All steers were adapted to the 90% concentrate diet, after which treatments were applied and blood was sampled via jugular catheters on d 7, 35, 63, 91, and 119 of the trial at 0, 1, 2, 3, 4, 6, 8, and 10 h after feeding. Averaged over sampling days, serum glucose concentrations did not differ (P > .10) among treatments at any sampling time (treatment x sampling time, P < .05). Average across sampling days and times, serum growth hormone, insulin, cholesterol, and triglyceride concentrations did not differ (P > .10) among treatments. No major effects of ionophores were noted for serum enzymes or protein fractions. Averaged over sampling times within day (treatment x day interaction, P < .10), both L and MT increased (P < .05) serum Ca and Na concentrations on d 91 and 119 compared with C. Serum inorganic P was increased (P < .10) for L vs MT and for ionophore treatments compared with C (P < .10) on several occasions (treatment x day x sampling time interaction, P < .05). Results suggest that ionophores do not cause dramatic changes in serum metabolic hormones or clinical chemistry profiles; however, monensin and lasalocid altered serum minerals in beef steers fed a high-concentrate diet.

Topics: Animal Feed; Animals; Blood Chemical Analysis; Blood Glucose; Blood Proteins; Blood Urea Nitrogen; Calcium; Cattle; Creatinine; Eating; Growth Hormone; Insulin; Lasalocid; Male; Monensin; Phosphorus; Random Allocation; Sodium; Tylosin; Weight Gain

The sensitivity of field isolates of Eimeria to monensin was investigated following the use of a commercial coccidiosis vaccine. Monensin was not effective against isolates from five commercial farms where ionophores had been used for many flocks. Monensin was more effective, however, against isolates obtained from the same farms following the use of a coccidiosis vaccine. No further improvement in drug efficacy was noted after five successive flocks in which the vaccine was used.

Topics: Animals; Chickens; Coccidiosis; Eimeria; Male; Monensin; Poultry Diseases; Protozoan Vaccines; Treatment Outcome; Weight Gain

1. An experiment was carried out with male broiler chicks to evaluate the combined effect of monensin (150 mg/kg) and the growth promoters (GPs) Zn bacitracin (BAC, 50 mg/kg), virginiamycin (VIR, 25 mg/kg) and avoparcin (AVO, 20 mg/kg) fed from 7 to 28 d of age on performance, utilisation of dietary nutrients, yield of defeathered eviscerated carcases (DEC) and size of various organs. The effect of the GPs in the monensin-unsupplemented diets fed up to 49 d of age on performance and carcase was also determined. 2. Monensin significantly (P < 0.05) depressed food intake, weight gain and food efficiency from 7 to 28 d of age. None of the GPs was able to counteract these effects. However, AVO slightly ameliorated them. AVO also significantly increased food intake and improved gain and food efficiency during 7 to 28, but not 28 to 49 or 7 to 49 d of age. VIR and BAC did not affect performance in either age period. 3. Monensin did not affect the utilisation of dietary dry matter, fat or energy, but it significantly decreased nitrogen utilisation. AVO improved nitrogen and fat utilisation and increased dietary AME(n) content. AME(n) was also increased by VIR. The utilisation of these nutrients was not affected by the interactions between monensin and the GPs. 4. Monensin did not affect yield of the DEC or the relative liver size at 31 d of age. It significantly increased the relative length of the small intestine (SI) and decreased its specific weight. AVO significantly increased yield at 31, but not at 53 d of age. BAC and VIR did not affect this variable. AVO and VIR, but not BAC, at both age periods reduced, at times significantly, the size, length and specific weight of the SI. 5. Our conclusions: BAC, VIR and AVO do not counteract the toxic effect of monensin. The effect of GPs in improving performance decreases and even disappears with age, while their effect in reducing the size of the SI is still evident in 49-d-old birds.

Topics: Animal Nutritional Physiological Phenomena; Animals; Anti-Bacterial Agents; Bacitracin; Chickens; Drug Interactions; Eating; Glycopeptides; Male; Monensin; Virginiamycin; Weight Gain

A study was conducted to determine the effects of feed restriction with subsequent gorging during extended water restriction on 27- to 57-d-old toms fed excess monensin. Four treatments were factorially arranged with two levels of dietary monensin (0 and 140 ppm) and two feeding-watering regimens (ad libitum and restricted). Ad libitum birds had full access to feed and water but restricted birds only had access to feed from 0800 to 1200 h daily. A 24-h water restriction regimen was imposed biweekly from 28 to 42 d and a 36-h water restriction regimen was imposed biweekly from 43 to 57 d. The restricted feeding and watering regimen decreased (P < .01) feed intake, weight gain, and feed efficiency. Excess monensin had no effect (P > .10) on feed intake regardless of feeding and watering regimen. Monensin had no effect on the weight gain and feed efficiency of ad libitum birds, but monensin exacerbated the decrease on gain (monensin by regimen, P < .01) and feed efficiency (monensin by regimen, P < .09) induced by feed and water restriction. No treatment-related abnormalities were observed during either interim or terminal necropsies. Neither clinical signs of ionophore toxicity nor pathologic findings attributed to monensin treatment were observed during the study. Based on these observations, feed gorging and water restriction will not adversely affect the health status of, or increase the mortality rate of, 4- to 8-wk-old male turkeys fed monensin.

Topics: Animals; Eating; Fasting; Hyperphagia; Male; Monensin; Random Allocation; Turkeys; Water Deprivation; Weight Gain

The efficacy of semduramicin (AVIAX), a novel polyether ionophore, was profiled in a series of 57 battery tests conducted in the United States and the United Kingdom. The studies employed mixed and monospecific infections of Eimeria acervulina, Eimeria mivati/Eimeria mitis, Eimeria brunetti, Eimeria maxima, Eimeria necatrix, and Eimeria tenella derived from North American and European field isolates. Ten-day-old broiler cockerels in pens of 8 to 10 birds were continuously medicated in feed beginning 24 h before challenge in tests of 6 to 8 days' duration. At the use level of 25 ppm, semduramicin effectively controlled mortality, lesions, and weight gain depression that occurred in unmedicated, infected controls for all species. In comparison with 60 ppm salinomycin, semduramicin significantly (P < .05) improved weight gain against E. brunetti and E. tenella, lesion control against E. brunetti and E. maxima, and the control of coccidiosis mortality against E. tenella. Salinomycin was superior (P < .05) to all treatments in maintenance of weight gain and control of lesions for E. acervulina. Maduramicin at 5 ppm was inferior (P < .05) to semduramicin in control of E. acervulina and E. maxima lesions, but was superior (P < .05) to all treatments in maintenance of weight gain and control of lesions in E. tenella infections. The data indicate that semduramicin at 25 ppm is well tolerated in broilers and possesses broad spectrum anticoccidial activity.

Topics: Animals; Anti-Bacterial Agents; Chickens; Coccidiosis; Eimeria; Lactones; Male; Monensin; Nigericin; Poultry Diseases; Pyrans; Species Specificity; Treatment Outcome; Weight Gain

Two hundred ten spring-born English crossbred beef heifers were used in two experiments in consecutive years using a randomized complete block design. The objectives were to determine the effects of increasing dietary intake of ruminally undegradable protein or propionic acid on the occurrence of puberty and to elucidate the mechanism by which monensin decreases age of puberty in beef heifers. Diets were fed for 120 d beginning in mid-November and consisted of mature grass hay and barley straw with .45 kg.animal-1 x d-1 supplement (CON) formulated to obtain .4 kg.animal-1 x d-1 of BW gain; .5 kg of supplement similar to CON and containing an additional 250 g of ruminally undegradable intake protein supplied from blood and corn gluten meal (UIP); .45 kg of supplement similar to CON composition and containing 400 g.animal-1 x d-1 of a 50% water and 50% propionic acid mixture (PROP); or .45 kg of supplement similar to CON supplying 200 mg.animal-1 x d-1 of monensin (MON). The hay:straw ratio in each diet was adjusted biweekly, to maintain similar BW gains for heifers fed each dietary treatment. As planned, BW gains were similar (P > .1) for all heifers. The heifers fed MON were 21 d younger (P < .05) at first estrus than heifers fed UIP; CON and PROP were intermediate and similar to heifers fed MON and UIP. The heifers fed UIP were 7 to 8 kg heavier (P < .05) at puberty than CON- or PROP-treated heifers. The heifers fed PROP were 6 kg heavier (P < .1) at puberty than heifers fed MON. Heifers that received UIP required less (P < .05) TDN than did heifers that received CON or PROP to achieve similar gain. Pregnancy rate was similar for all treatment groups. Feeding UIP in excess of NRC CP requirements may improve energy utilization of heifers fed mature roughages but may delay the onset of puberty compared with heifers fed monensin. This study demonstrated that nutrient composition of the diet may influence age of puberty independent of growth rate.

Topics: Animal Feed; Animals; Blood Glucose; Blood Urea Nitrogen; Cattle; Cholesterol; Dietary Proteins; Eating; Female; Fertility; Growth Hormone; Insulin; Monensin; Pregnancy; Propionates; Random Allocation; Sexual Maturation; Weight Gain

One feedlot trial (116 d; 192 steers) with a factorial arrangement of treatments was conducted to determine effects of supplemental fat and ionophores in corn-based finishing diets. Factors were level of fat (0 or 4% tallow) and ionophore type (none [N], lasalocid [L], monensin plus tylosin [MT], or daily rotation of L and MT [LMT]); L, M, and T were fed at 31, 25, and 10 ppm (DM basis), respectively. Fat and ionophore interacted for DMI (P < .10), ADG (P < .01), and gain:feed G/F, P < .05). Compared with 0%-fat diets, 4% fat decreased (P < .005) DMI by steers fed MT by 8.9%. In 0%-fat diets, MT increased (P < .05) ADG and G/F compared with N or L; however, this increase was negated or reversed in 4%-fat diets. Fat and ionophore interacted (P < .16) on dietary NE concentration. In the 0%-tallow diet, MT increased NEm and NE(g) by 5.1 and 7.0%, respectively, but MT had not effect on NE concentration of the 4%-tallow diet. Alternate feeding of L and MT did not increase animal performance above that of separate, continuous feeding. Six ruminally fistulated steers were used in a metabolism study to evaluate potential mechanisms underlying the interactions observed in the feedlot trial. Treatments were the same as the feedlot trial, except that LMT was not included. Ruminal digesta kinetics were not altered (P > .30) by the addition of fat or ionophores to the diet. Fat and ionophore interacted (P < .05) for molar proportions of ruminal acetate and propionate.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adipose Tissue; Animal Feed; Animals; Cattle; Dietary Fats; Digestion; Eating; Fermentation; Ionophores; Kinetics; Lasalocid; Male; Meat; Monensin; Muscle Development; Random Allocation; Rumen; Tylosin; Weight Gain

Two feedlot growth performance trials and a metabolism trial were conducted to evaluate the relationship between monensin (MON) and sodium bicarbonate (BICARB) supplementation on utilization of a high-energy diet by finishing steers. Two levels of MON (0 and 33 mg/kg of diet) and two levels of BICARB (0 and .75% DM) were compared in a 2 x 2 factorial arrangement of treatments. The basal diet contained 75% steam-flaked corn, 4% yellow grease, and 12% forage (DM basis). There were no interactions between supplemental BICARB and MON on feedlot growth performance or characteristics of ruminal and total tract digestion. With either crossbred or Holstein steers there were no treatment effects (P > .10) on ADG, DM intake, feed efficiency, or NE value of the diet. The BICARB did not influence (P > .10) ruminal or total tract digestion of OM, ADF, starch, and N, ruminal pH, or ruminal VFA molar proportions. Monensin decreased (6.6%, P < .10) ruminal OM digestion. However, differences in ruminal digestion were compensated for by increased (3.2%, P < .05) postruminal OM digestion. Effects of MON on total tract digestion of OM, ADF, N, starch and GE were small (P > .10). Monensin decreased ruminal molar proportions of acetate (5.3%, P > .10) and butyrate (29.4%, P < .05) and increased molar proportions of propionate (16.3%, P < .10). Coupled with reduced ruminal OM fermentation, the increase in molar proportions of propionate caused a decrease in ruminal methane energy loss and increased diet ME (2.7%, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adipose Tissue; Animal Feed; Animals; Bicarbonates; Cattle; Dietary Fats; Digestion; Eating; Food, Fortified; Male; Monensin; Muscle Development; Muscles; Random Allocation; Rumen; Sodium; Sodium Bicarbonate; Weight Gain

Three trials were conducted with finishing steers to study the effect of feeding sorbitol alone or combined with monensin. For each trial 15 pens of eight steers were fed high-corn-silage diets. In the first two trials three pens of eight steers each were fed no additive, 35 g of sorbitol, 350 mg of monensin, or 30 g of sorbitol plus 350 mg of monensin per day. In Trial 1 three pens were fed 200 g of sorbitol per animal every 6 d, and in Trial 2 three pens were fed 60 g/d of sorbitol plus 350 mg/d of monensin. For the third trial, three pens were fed 0, 20, 40, or 80 g/d of sorbitol per animal and three pens were fed 40 g/d after 56 d; all the steers were fed 350 mg/d of monensin. In the first trial sorbitol had no effect on daily gain, and monensin increased (P < .05) daily gain. Intake of DM was lower (P < .05) for the steers fed sorbitol (35 g/d). Dry matter intake/gain was improved by feeding monensin (P < .05) or 35 g/d of sorbitol (P < .07). The improvement amounted to 18% when the additives were used in combination. In the second trial daily gains were similar for the cattle fed all diets. Dry matter intake was lower (P < .05) for steers fed monensin or 60 g/d of sorbitol and tended to be lower (P < .12) for the cattle fed 35 g/d of sorbitol. Dry matter intake/gain tended to be lower for cattle fed monensin and sorbitol, especially when fed in combination.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animal Feed; Animals; Blood Glucose; Cattle; Cholesterol; Dietary Carbohydrates; Digestion; Eating; Food, Fortified; Male; Meat; Monensin; Sorbitol; Triglycerides; Weight Gain

Four experiments were conducted to determine the effect of adding corn gluten mean (CGM) or soybean meal (SBM) at 24- or 48-h intervals to diets based on corn stalks. In each experiment corn stalks was the primary diet ingredient fed to wethers or steers. Monensin was also fed to determine whether its effects on ruminal fermentation would improve the efficiency of N utilization under these conditions. Evaluation criteria included ruminal fermentation characteristics, DM intake and utilization, N balance in sheep, and steer feedlot performance. Ruminal ammonia nitrogen (NH3 N) concentrations measured over time were higher (P < .05) when diets contained SBM. Diet did not influence (P > .10) total VFA concentrations in ruminal fluid. Differences in diurnal shifts in ruminal NH3 N and total VFA due to protein source resulted in diet x hour interactions (P < .05). Dry matter intake response to protein source and frequency of supplement feeding was variable. Dry matter digestibility and nitrogen digestibility were not affected (P > .10) by protein source or feeding interval. The 48-h interval feeding of CGM was favorable compared with 24-h interval feeding (P < .05). The opposite response occurred with SBM, resulting in a diet x feeding interval interaction (P < .05). Nitrogen retention was greater (P < .05) when CGM was fed and with alternate day feeding. Diets that contained CGM supported higher (P < .05) ADG and gain/feed than diets that contained SBM when fed to steer calves. Alternate day feeding of supplements that contained monensin was detrimental to steer performance under the conditions of these experiments. Corn gluten meal is an effective substitute for SBM when alternate day protein supplementation is practiced.

Topics: Ammonia; Animal Feed; Animals; Blood Urea Nitrogen; Cattle; Dietary Proteins; Digestion; Eating; Fatty Acids, Volatile; Fermentation; Food, Fortified; Glutens; Glycine max; Male; Monensin; Nitrogen; Random Allocation; Rumen; Sheep; Weight Gain; Zea mays

The objective was to determine the effect of feeding monensin on growth performance, average age at breeding, and body composition of Holstein heifers. Forty heifers were divided by weight into two groups, averaging 330 kg (heavy) and 217 kg (light) at the beginning of the trial. Within each weight group, heifers were assigned randomly to either of two treatments: without or with monensin feeding (200 mg per head daily). All heifers were fed diets containing either corn silage at 2% BW or ad libitum grass pasture supplemented with concentrates (1 to 1.5 kg per head daily). Monensin had no effect on BW, average daily gain, height at withers, heart girth, length, coccae width, or body condition score. Feeding monensin significantly decreased the age at breeding by 15 and 24 d and age at calving by 36 and 61 d for heavy and light heifers, respectively. Estimated empty body water, protein, or fat percentages determined by urea space were not affected by monensin. Heavy heifers contained a smaller percentage of empty body water but higher percentages of empty body protein and fat than light ones. The results from this study indicate that monensin can reduce age at puberty in Holstein heifers without affecting BW and composition.

Topics: Adipose Tissue; Animals; Body Composition; Cattle; Female; Heart; Monensin; Poaceae; Random Allocation; Reproduction; Sexual Maturation; Silage; Weight Gain; Zea mays

A series of experiments was conducted to determine the effects of limit-feeding high-concentrate (LFHC) diets on dietary CP requirements of steer calves. When steer calves were fed 80% concentrate diets at 78 g/kg of BW.75, increasing dietary CP resulted in increased ADG (P less than .001). Average daily gain was increased in steers as daily monensin dosage increased from 120 to 180 mg (P less than .05). Increasing the daily monensin dosage to 240 mg did not increase ADG further. There were no (P greater than .10) CP X monensin interactions, suggesting that the monensin response was caused by improved energy utilization and not be the possible protein-sparing effects of ionophores. Steer calves in the second feedyard experiment expressed similar ADG when provided equal NEg as limit-fed, high-moisture ear corn (HMEC) or when given ad libitum access to corn silage. The basal diet did not affect the steers' daily N requirement for growth. Gain per unit of protein intake declined quadratically (P less than .05) with increasing CP intake, indicating that CP requirements were near NRC estimates on both diets. The corn silage-based diet was less digestible (70.3 vs 77.4%; P less than .01) than the HMEC diet when fed to lambs. Fecal output differed (P less than .10) substantially (342 g/d of corn silage vs 205 g/d of HMEC), whereas fecal N output was only slightly higher (6.97 vs 6.34 g/d, respectively; P less than .10). Limited feeding of higher-concentrate diets to steer calves seemed to be an effective management procedure and did not cause acute digestion upset.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Analysis of Variance; Animal Feed; Animals; Cattle; Dietary Proteins; Eating; Energy Metabolism; Food Deprivation; Male; Monensin; Nitrogen; Sheep; Weight Gain

In vivo and in vitro experiments were conducted in an effort to elucidate the mechanism of suppression by halofuginone of skin strength in broilers. In the in vivo study, halofuginone was included at concentrations of 0, 1.5, 3, and 6 mg/kg of diet, corresponding to 0, 50, 100, and 200%, respectively, of the amount recommended for use as a coccidiostat. Each dietary treatment was given to 260 female broiler day-old chickens. Skin tearing was evaluated at the processing plant. Skin collagen and Kjeldahl-nitrogen were determined chemically. At the age of 7 wk, BW and feed efficiency were affected only in birds consuming the diet containing the highest concentration of the drug. Skin tearing increased but skin collagen concentration decreased in a dose-dependent manner. Fibroblasts were obtained by collagenase digestion from chicken skin and cultured. The cultured cells were incubated with various concentrations of halofuginone, monensin, and nicarbazin, and [3H]proline incorporation was evaluated in collagenase-digestible (representing mostly collagen) and nondigestible proteins exported by the cells into the medium. Halofuginone, at a concentration as low as 10(-11) M, inhibited incorporation of [3H]proline into collagenase-digestible proteins, but did not affect incorporation of [3H]proline into collagenase-nondigestible proteins. Even at concentrations as high as 10(-9) M, neither monensin nor nicarbazin affected collagenase-digestible proteins. The in vitro results suggest that halofuginone specifically inhibits collagen synthesis by skin fibroblasts. Results of both in vivo and in vitro trials suggest that the increase of skin tearing during processing, induced by halofuginone, is caused by direct suppression of skin collagen synthesis.

Topics: Animals; Cells, Cultured; Chickens; Coccidiostats; Collagen; Dose-Response Relationship, Drug; Female; Fibroblasts; Monensin; Nicarbazin; Piperidines; Quinazolines; Quinazolinones; Random Allocation; Skin; Weight Gain

Efficacy of virginiamycin (22 mg/kg) in combination with no drug, amprolium, carbarsone, halofuginone, or monensin, was studied. Male and female turkeys were raised to market age in five experiments conducted from 1983 to 1987. Body weights and feed:gain responses to virginiamycin for males and females were positive and significant (P less than .05). Virginiamycin resulted in mean 5.2 and 6.3% body weight responses and 3.3 and 2.2% feed:gain responses for males at 19 or 20 wk of age and for females at 16 or 17 wk of age, respectively. Mortality rates were low in all studies, and were not influenced by virginiamycin. In a processing study, virginiamycin in combination with halofuginone did not affect shrinkage, yield, or market grade. Feed was utilized by males and females 3.9 and 3.0%, respectively, more efficiently than expected with dietary virginiamycin, compared with results predicted by a simulation modeling technique. Profitability was considerably greater with dietary virginiamycin using actual data than with simulated feed consumption data.

Topics: Amebicides; Amprolium; Animal Feed; Animals; Arsanilic Acid; Drug Interactions; Eating; Energy Metabolism; Female; Male; Monensin; Mortality; Piperidines; Quinazolines; Quinazolinones; Sex Characteristics; Turkeys; Virginiamycin; Weight Gain

Two trials were conducted to evaluate the effects of feeding various anticoccidial products to turkeys to 8 wk and then growing to market age (16 wk for hens and 20 wk for toms). Anticoccidials evaluated in the first trial included amprolium at 187.5 mg/kg for 0 to 4 wk and 125 mg/kg for 4 to 8 wk; butynorate at 375 mg/kg for 0 to 8 wk; monensin at both 60 (MON-60) and 100 mg/kg for 0 to 8 wk; zoalene at 187.5 mg/kg for 0 to 4 wk and 125 mg/kg for 4 to 8 wk; and halofuginone at 3 mg/kg for 0 to 8 wk. In the second trial, MON-60 was replaced by a combination of sulfadimethoxine (62.5 mg/kg) plus ormetoprim (37.5 mg/kg) for 0 to 8 wk. In each trial each treatment was fed to four pens of 16 hens and four pens of 12 toms. Several of the anticoccidials significantly influenced the weight of both hens and toms by producing lower weights at the end of the 8-wk feeding period than birds in other treatments. However, after removal of the anticoccidials, compensatory gains were observed in almost every instance. Significant effects of previous anticoccidial feeding were noted on body weight of hens at 16 wk but not on weights of toms at 20 wk.

Topics: Amprolium; Animal Feed; Animals; Coccidiostats; Dietary Fats; Dinitolmide; Eating; Female; Male; Monensin; Organotin Compounds; Piperidines; Pyrimidines; Quinazolines; Quinazolinones; Random Allocation; Sulfadimethoxine; Turkeys; Weight Gain

Two trials were conducted to compare the efficacy of currently approved anticoccidials for turkeys against challenge using a field isolate of mixed Eimeria species; E. adenoides, E. gallopavonis, and E. meleagrimitis. Poults in wire-floored cages were fed unmedicated diets from day-old to 3 wk of age. Diets were supplemented with either amprolium (AMP, 125 mg/kg), butynorate (BUT, 375 mg/kg), monensin (MON-60, 60 mg/kg; MON-100, 100 mg/kg), halofuginone (HAL; 3 mg/kg), zoalene (ZOA; 125 mg/kg), or sulfadimethoxine plus ormetoprim (SUL + ORM, 62.5 mg/kg and 37.5 mg/kg, respectively). After 2 days on the test diets, poults were individually weighed and inoculated with sporulated coccidial oocysts from the field isolate. Total fecal collections were obtained for Days 0 to 5 and 6 to 10 to estimate oocyst output. At 10 days postinoculation, the birds were individually weighed and killed to determine severity of intestinal lesions. The HAL and MON were most effective and AMP, ZOA, and SUL + ORM were least effective in maintaining weight and in reducing the severity of intestinal lesions. All the coccidiostats tested reduced oocyst passage, but poults fed HAL produced fewer oocysts. The results demonstrated differences in efficacy among anticoccidials with the more recently approved drugs providing the best protection against coccidiosis.

Topics: Amprolium; Animals; Coccidiosis; Coccidiostats; Dinitolmide; Feces; Intestines; Male; Monensin; Organotin Compounds; Piperidines; Poultry Diseases; Pyrimidines; Quinazolines; Quinazolinones; Sulfadimethoxine; Turkeys; Weight Gain

Diets supplemented with either 22 mg of virginiamycin per kg, 99 mg monensin sodium per kg, or both, were fed to 960 Hybrid-1500 Medium White poults from day-old to slaughter at 12 wk of age. Weight gains from 0 to 12 wk were greater when the diet was supplemented with virginiamycin, alone or in combination with monensin (P less than .05). However, the combination of virginiamycin with monensin resulted in superior overall feed efficiency to that obtained with either additive alone.

Topics: Animals; Diet; Female; Male; Monensin; Random Allocation; Turkeys; Virginiamycin; Weight Gain

An experiment was conducted with 5- to 18-day-old Arbor Acres broiler chicks to evaluate the interaction of sodium zeolite A (NZA) and monensin in uninfected and in coccidiosis-infected chicks. Sodium zeolite A (0 and .75%) or monensin (0 and 121 ppm), or both, were fed to uninfected chicks or to chicks infected with 4 x 10(5) sporulated, Eimeria acervulina oocysts, resulting in a 2-by-2-by-2 factorial arrangement of treatments. Coccidial infection reduced (P less than .01) weight gain, feed intake, feed efficiency, percentage of bone ash and of bone calcium; but the infection increased (P less than .05) bone Zn percentage. Monensin alleviated (or at least partially so) the adverse effects of the coccidial infection on weight gain, feed intake, feed efficiency and percentage of bone ash (coccidiosis by monensin, P less than .01). In addition, monensin increased the bone-calcium (P less than .06) and zinc content (P less than .02) in uninfected chicks and in those infected with coccidiosis. Sodium zeolite A tended to reduce feed intake by coccidiosis-infected chicks (coccidiosis by NZA, P less than .07), but increased (P less than .01) the bone zinc and decreased (P less than .01) serum inorganic phosphorus in uninfected chicks and in those infected with coccidiosis.

Topics: Aluminum Silicates; Animals; Chickens; Coccidiosis; Eating; Ionophores; Monensin; Poultry Diseases; Weight Gain; Zeolites

Interactions among grain type (grain sorghum, corn or wheat), roughage level and monensin level were studied in four feedlot trials using pen-fed crossbred yearling cattle. In Trial 1, cattle fed high-moisture corn (HMC) were more efficient (.1537 vs .1406 for gain/feed; P less than .01) than cattle fed dry-rolled grain sorghum (DRGS). As level (0, 3, 6, 9%) of dietary roughage was increased, feed efficiency (gain/feed) decreased (.1566, .1461, .1479, .1382; linear, P less than .01). In Trial 2, a grain type (DRGS; dry-rolled corn, DRC; dry-rolled wheat, DRW) x roughage level interaction was observed for daily gain and feed efficiency. Feed efficiency (gain/feed) was decreased when roughage was added to diets containing DRC (.1608 vs .1750) or DRGS (.1674 vs .1465), but not to the diet containing DRW (.1664 vs .1607). In trial 3, a grain type x roughage level x monensin level interaction (P less than .08) was observed for feed efficiency. The addition of 27.5 mg of monensin per kilogram of the 0% roughage-DRC diet tended to improve feed efficiency (.1633 vs .1531), but the addition of monensin to the 7.5% roughage-DRC diet tended to depress feed efficiency (.1476 vs .1575). The addition of either roughage (.1493 vs .1420) or monensin (.1500 vs .1413) to the DRW diet improved feed efficiency. In Trial 4, cattle fed a combination of 75% DRW and 25% DRC were more efficient (.1618 vs .1591; P less than .06) than cattle fed DRC. As level of roughage (0, 3.75, 7.5%) increased, feed efficiency decreased linearly (.1645, .1599, .1569; P less than .0001). Monensin had no effect on feed efficiency. The value of feeding roughage and monensin was variable both across grain types and within similar grain types.

Topics: Acidosis; Animal Feed; Animals; Cattle; Cattle Diseases; Dietary Fiber; Digestion; Eating; Edible Grain; Liver Abscess; Male; Monensin; Starch; Weight Gain

A total of 28 trials utilizing 2,262 steers and heifers were conducted to evaluate a sustained monensin2 ruminal delivery device (RDD) on the daily gain of grazing cattle. Five series of trials, with four to eight trials per series within a grazing season, were conducted to evaluate the daily gain response under different environmental conditions and locations. Pastures grazed included both summer (cool- and warm-season grasses and native range) and winter (rye, ryegrass and wheat) growing pastures. The experimental design for all trials in each of five series was a randomized complete block with initial weight or breed as the blocking factor. The treatments compared in series I, III, IV and V (20 trials) were a control and a single RDD, whereas in series II (eight trials), a 2 x 2 factorial was utilized that compared RDD and estradiol 17-beta controlled release implants. In the five series of trials, the monensin RDD increased daily gain .04 (P = .002), .03 (P = .07), .09 (P = .01), .05 (P = .10) and .08 kg (P = .04) compared with the controls. Use of the RDD provided an effective method of achieving consistent monensin delivery and weight gain improvement without requiring the extra labor needed to administer monensin via hand-feeding or self-feeding supplements, blocks or loose mineral.

Topics: Animal Feed; Animals; Cattle; Delayed-Action Preparations; Female; Male; Monensin; Poaceae; Rumen; Secale; Weight Gain

Two trials were conducted to evaluate the effects of ionophore rotation programs on performance and digestion by feedlot cattle. A 90% concentrate diet was fed with treatments of no ionophore (C), 33 mg lasalocid/kg diet daily (L), 29 mg monensin plus 11 mg tylosin/kg diet daily (MT), and daily (D) and weekly (W) rotation of L and MT. In Trial 1, feedlot performance of 200 crossbred steers (average initial BW 296 kg) was evaluated during a 133-d period. In Trial 2, four crossbred steers (average initial BW 376 kg) fitted with ruminal, duodenal and ileal cannulas were used in a 4 x 4 Latin square design to evaluate treatment effects (excluding W) on ruminal fermentation and site and extent of digestion. In Trial 1, daily rotation of L and MT improved (P less than .10) feed:gain ratio compared with other treatment groups, but daily feed intake did not differ (P greater than .10) among treatments. Daily gain was greater (P less than .10) for steers fed D than for those fed C or MT, but not different from that of steers fed L or W. Carcass measurements did not differ (P greater than .10) among treatments. In Trial 2, ruminal molar proportions of butyrate and valerate were decreased (P less than .07) by MT and D compared with C and L. Proportions of other VFA, ammonia concentrations and ruminal pH did not differ among treatments. Ionophore treatments did not affect site or extent of digestion of OM, starch or N; no differences among treatments were observed for efficiency of microbial protein synthesis. Although daily rotation of L and MT improved performance of growing-finishing feedlot steers, this improvement was not attributable to alterations in ruminal fermentation, or in site or extent of nutrient digestion.

Topics: Animals; Cattle; Digestion; Drug Combinations; Eating; Fatty Acids, Volatile; Fermentation; Hydrogen-Ion Concentration; Lasalocid; Male; Monensin; Rumen; Tylosin; Weight Gain

Three trials were conducted to compare effects of restricted intake of high-concentrate diets vs ad libitum intake of corn silage diets during the growing phase on feedlot cattle performance. In Trial 1, 120 steers (initial BW, 246 kg) were fed 1) a corn silage-based diet ad libitum, 2) a high-moisture corn-corn silage-based diet with intake restricted to a level 20% less than that of the corn silage diet or 3) a high-moisture corn-based diet with intake restricted to a level 30% less than that of the corn silage diet. Steers fed the 20% restricted corn-corn silage-based diet tended (P = .07) to gain slower than those fed the corn silage or 30% restricted high-concentrate diet. Feed efficiency and diet digestibility were greatest for steers fed the 30% restricted-intake, high-concentrate diet (P less than .01). Performance of steers during the subsequent 118-d finishing period was not affected (P greater than .65) by source of energy during the growing period. In Trial 2, ADG of steers fed the 30% intake-restricted, high-concentrate diet was lower (P less than .01) than that of steers with ad libitum access to corn silage. During the 84-d growing period, steers fed supplemental blood meal had 8.3% greater gains and a 6% greater efficiency of feed use than those fed supplemental soybean meal (P less than .01). Monensin did not affect (P = .82) performance of steers fed 30% restricted-intake diets. During the 76-d finishing period, gains and feed conversion were improved (P less than .01) for steers fed the restricted-intake diet in the growing period compared with those given ad libitum access to corn silage. During the growing period in Trial 3, ADG of steers restricted-fed an all-concentrate diet were slightly greater (P less than .10) than ADG of those given ad libitum access to corn silage. Gains did not differ (P = .37) during the subsequent finishing period when steers were switched to 85 or 100% concentrate diets. We concluded that intake of all concentrate diets can be restricted to achieve gains equal to those of steers given ad libitum access to corn silage-based diets without detrimental effects on finishing performance.

Topics: Animal Feed; Animals; Cattle; Dietary Proteins; Digestion; Eating; Male; Monensin; Silage; Weight Gain; Zea mays

One thousand twenty steers and heifers were used in six feeding trials to examine the influence of laidlomycin propionate on feedlot performance and to determine the most efficacious dietary concentrations of that ionophore. Cattle were fed diets ranging in energy content from 1.08 to 1.49 Mcal NEg/kg of DM. Laidlomycin propionate improved rate of gain and feed conversion in both steers and heifers. Improvements in performance were not evident when laidlomycin propionate was fed at only 3 mg/kg. However, both average daily gain and feed conversion were improved by laidlomycin propionate within the range of 6 to 12 mg/kg of DM (P less than .001). Feed consumption was not substantially affected by inclusion of laidlomycin propionate in the diet. Improvements in ADG and feed conversion were greater on lower-energy diets than on higher-energy diets, but both these performance characteristics were improved regardless of the type of diet fed. Average daily gain was maximized with laidlomycin propionate at 6 mg/kg, whereas improvements in feed conversion were sustained through 12 mg/kg. Carcasses of cattle fed diets containing 6 to 12 mg/kg of laidlomycin propionate weighed 7.3 kg more (P less than .001) than carcasses of cattle fed the control diets. Yield grade and quality grade were not affected by laidlomycin propionate (P greater than .05).

Topics: Animal Feed; Animals; Cattle; Digestion; Dose-Response Relationship, Drug; Eating; Energy Intake; Female; Male; Monensin; Weight Gain

Effects of supplemental feed and of ionophore concentration in supplemental feed on gastrointestinal rate parameters, forage intake and weight gain were measured in individually supplemented grazing lambs and Angora kid goats. The 12 dietary treatments included negative control (NC; grazed forage only), positive control (PC; grazing plus 13.6 g supplement DM/kg.75), and PC plus monensin or lasalocid, each at 33, 66, 99, 132 or 165 mg/kg in the supplement. Gastrointestinal fill, retention time, turnover rate and fecal output were estimated by applying a single-compartment model to the fecal excretion of a single dose of ytterbium. Forage digestibility was estimated from forage and fecal concentrations of indigestible fiber. Supplemental feed increased digestibility of forage and total intake in sheep but had no effect on forage intake. In goats, supplemental feed did not increase digestibility of forage but decreased forage intake. Supplemental feed increased weight gain in both species. Increasing the monensin concentration in supplemental feed reduced supplement intake greatly in sheep and slightly in goats. Lasalocid did not affect intake of supplement by either sheep or goats. Overall, ionophores had minimal effects on the response criteria. Because feed intake and digestibility were not affected, any increase in gain or efficiency in lambs or kid goats on rangeland from consumption of ionophores must be a result of their therapeutic value or of improved physiological efficiency.

Topics: Animal Feed; Animals; Digestion; Digestive System; Eating; Female; Food, Fortified; Goats; Ionophores; Lasalocid; Male; Monensin; Sheep; Texas; Weight Gain

Four chick and five poult trials were conducted in order to investigate the anticoccidial efficacy of monensin against Eimeria mitis in chickens and Eimeria dispersa in turkeys. The chicks were fed a basal diet with either 0 or 100 ppm of monensin. The poults were fed a basal diet with either 0 or 60 ppm of monensin. Two days after the initiation of each experiment, the chicks and poults were crop-intubated with oocysts of E. mitis and E. dispersa, respectively. A group was also included that was not infected and not medicated. Growth and feed intake were recorded. At 6 or 7 days postinoculation, the birds were killed by cervical dislocation and were scored for the incidence and severity of intestinal abnormalities. The Eimeria mitis infection reduced (P less than .01) gain and the feed:gain ratio, compared with uninfected birds; the E. dispersa infection only reduced (P less than .05) gain. Although well-defined, discrete lesions were not observed, marked intestinal abnormalities were noted in birds infected with either E. mitis or E. dispersa. Also, the infected, unmedicated birds had increased (P less than .01) intestinal scores compared with uninfected birds or those with infection but treated with monensin. Monensin eliminated the reduction in gain and feed efficiency seen in the infected birds. The infected birds fed monensin had intestinal scores, gain, and feed:gain ratios similar (P greater than .10) to those for the birds that were not infected and that did not receive medication.

Topics: Animals; Chickens; Coccidiosis; Eating; Intestines; Male; Monensin; Poultry Diseases; Turkeys; Weight Gain

Eight feeding experiments (4 on pasture and indoors each) with 401 growing cattle were carried out in order to measure the influence of a monensin device on daily weight gain. The monensin device effected on the average 7 g (1.4%) and 37 g (4.3%) higher daily weight gain on pasture and indoors resp. (P greater than 0.05). The weight gain of animals varied between 92.5 and 112.5% compared with the unsupplemented groups. The monensin device caused a higher weight gain of easier cattle than of heavier ones (greater than 300 kg body weight). The device has had no significant effect on figures of rumen fermentation. Probably the monensin level delivered from the device (100 +/- 50 mg per animal and day) is to low for heavier cattle.

Topics: Animals; Cattle; Delayed-Action Preparations; Female; Fermentation; Male; Monensin; Rumen; Weight Gain

The effects were examined of monensin and the bambermycins in feed on growing turkeys. The drugs were used alone and in combination. A total of 1,600 hen and tom turkeys were divided into 32 pens. Four treatments were used, including 45 or 90 g/ton (907 kg) monensin either to 10 wk of age or to market age with and without adding of 2 g/ton of bambermycins. Evaluation parameters, including body weight, feed efficiency, and mortality, were done at 6, 10, and 13 wk of age for hens and 6, 10, and 18 wk of age for toms. Adding bambermycins increased body weights of hens at 10 wk of age and toms at 6 and 10 wk of age. No differences among treatments were noted at market weight within any of the parameters studied. No differences among treatments were noted in efficiency or mortality by the conclusion of the trial.

Topics: Aminoglycosides; Analysis of Variance; Animal Feed; Animals; Anti-Bacterial Agents; Bambermycins; Female; Male; Monensin; Random Allocation; Turkeys; Weight Gain

Twenty-five Brangus (BR) and 15 Angus (AN) heifers were used to study the effects of breed and wintering diet on average daily gain (ADG), onset of puberty and plasma concentrations of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). Wintering diets (fed for 107 days beginning November 15) consisted of the following: 1) native grass hay (NGH), 2) ammoniated NGH, 3) NGH plus cottonseed meal, 4) Diet 3 plus corn and 5) Diet 4 plus monensin. After wintering, heifers were transferred to ryegrass pasture for 70 days. Mean ADG during the wintering phase were -.20, -.10, .17, .29 and .39 kg for heifers fed Diets 1 through 5, respectively (P less than .01). ADG was greater (P less than .05) for BR than for AN heifers. Plasma concentrations of GH were higher (P less than .05) in heifers fed Diets 1 and 2 than in heifers fed Diets 3, 4 or 5. Plasma concentrations of IGF-1 were lowest in heifers fed Diet 1 and highest in heifers fed Diets 4 and 5. During ryegrass grazing, GH concentrations were similar for all groups. However, concentrations of IGF-1 were higher (P less than .05) in heifers fed Diets 3, 4 and 5 than in heifers fed Diets 1 and 2. Age at puberty (onset of cyclic progesterone concentrations) was greatest in heifers fed Diet 1 and lowest in heifers fed Diet 5. Weight at puberty was not affected (P greater than .10) by wintering diet but was greater (P less than .01) in BR than in AN heifers. Therefore, negative ADG appears to be associated with elevated plasma GH concentrations in heifers, and plasma IGF-1 concentration appears to be a more accurate indication of nutritional status than plasma concentrations of GH.

Topics: Aging; Animals; Cattle; Diet; Female; Growth Hormone; Insulin-Like Growth Factor I; Monensin; Seasons; Sexual Maturation; Somatomedins; Weight Gain

When they were turned out to grass in May 1987 for their first season, 10 calves were dosed with a 5 x 750 mg oxfendazole pulse release bolus (OPRB) and a monensin sodium rumen delivery device (RDD); eight calves received one OPRB; 10 calves received one RDD and eight calves received neither bolus. Each group was set-stocked on individual paddocks which had been grazed during the previous season by cattle which developed clinical parasitic gastroenteritis and bronchitis (husk). In July, before they were due to be moved to new pastures in mid-summer, and before they were dosed strategically with levamisole HCl, some of the calves not dosed with an OPRB succumbed to clinical parasitic gastroenteritis and husk and received emergency anthelmintic treatment, after which no further clinical episodes occurred. The 'dose and move' strategy was implemented in early August after which both groups not dosed with an OPRB were set-stocked together until the trial ended on October 14, 147 days after turn out. The two groups of calves which had received the OPRB were also moved to new pasture and set-stocked together until the end of the trial. No evidence of clinical helminthiases developed in either of the two groups of calves dosed with OPRBs and their faecal worm egg and larval counts, and plasma pepsinogen activities remained low. They gained significantly more weight than the two groups of calves not dosed with OPRBs (P less than 0.001). The bolus types were compatible and induced no untoward side-effects when used together.

Topics: Animals; Anthelmintics; Benzimidazoles; Cattle; Cattle Diseases; Delayed-Action Preparations; Drug Therapy, Combination; Female; Gastroenteritis; Helminthiasis; Helminthiasis, Animal; Male; Monensin; Parasite Egg Count; Random Allocation; Rumen; Weight Gain

Two trials evaluated the effects of a monensin ruminal delivery device (MRDD) on steers grazing winter wheat pasture. In Trial 1, 60 Hereford steers (initial wt 238.5 kg) grazed a 21.9-ha paddock of Vona-variety winter wheat for 112 d. Steers were assigned to either MRDD or control (C) treatments in a randomized complete block design. In Trial 2, eight ruminally cannulated steers (avg wt 234.4 kg) grazed a 2.4-ha paddock of Vona-variety wheat and were assigned randomly to either MRDD or C treatments. Three 11-d collection periods were conducted during early February, early March and early April. Chromic oxide was dosed to determine fecal output, and ruminal samples were collected on d 6 of each period. Nylon bags containing ground wheat forage were incubated ruminally beginning on d 8. In Trial 1, steers with MRDD tended (P less than .11) to gain more weight than C steers (.44 vs .38 kg/d). In Trial 2, wheat forage intake, in situ DM disappearance, ruminal pH, ruminal ammonia concentrations and ruminal proportions of acetate and total VFA concentrations were not affected by treatment. Ruminal proportions of propionate were increased (P less than .05) slightly by MRDD (20.3 and 19.2 mol/100 mol for MRDD and C, respectively). Butyrate proportions in ruminal samples were decreased (P less than .05) by MRDD during March but not in other sampling periods. Ruminal fluid chlorophyll concentration was less (P less than .05) for MRDD-treated vs C steers during early March but was greater (P less than .10) for MRDD-treated steers during early April. The MRDD shows promise as a method of supplying monensin to cattle grazing winter wheat forage.

Topics: Animal Feed; Animals; Cattle; Delayed-Action Preparations; Eating; Fermentation; Male; Monensin; Random Allocation; Rumen; Triticum; Weather; Weight Gain

In two feeding experiments with 10 dairy cows each the effect of 200 mg monensin Na per animal and day in rations either rich in roughage or in concentrate was studied. In principle, the reactions caused by monensin supplement did not differ between the two types of rations. Monensin supplements resulted in a slight reduction of feed intake, a significantly lower milk fat content and, as a tendency, also a lower milk protein, particularly casein, content and a diminished amount of fat corrected milk (FCM). The pattern of fatty acids in the rumen was shifted in favour of propionic acid and the live weight gain of the cows was higher in the monensin group. There were no improvements with regard to the expenditure of feed and energy per kg FCM.

Topics: Animal Feed; Animals; Cattle; Eating; Fatty Acids; Female; Lactation; Milk Proteins; Monensin; Pregnancy; Rumen; Weight Gain