lasalocid and Body-Weight

Carboxylic polyether ionophores, when fed to growing ruminants improve efficiency of production. This review summarizes the observed effects of ionophores on the ruminal fermentation and the host animal. The effect of ionophores on prokaryotic and eukaryotic cells is described and this knowledge is then utilized to explain many of the observed ionophore effects on the rumen fermentations and host gastrointestinal physiology.

Topics: Animal Diseases; Animals; Animals, Domestic; Artiodactyla; Bacteria; Biological Transport, Active; Body Weight; Cattle; Electron Transport; Energy Metabolism; Eukaryota; Fermentation; Food Additives; Ionophores; Lasalocid; Membrane Potentials; Models, Chemical; Monensin; Nitrogen; Rumen

Two experiments were designed to evaluate the impacts of supplementing lasalocid (LAS), narasin (NAR), or virginiamycin (VRM) on rumen fermentation parameters, apparent nutrient digestibility, and blood parameters (Exp. 1), as well as feed intake and performance (Exp. 2) of Nellore cattle consuming a forage-based diet. In Exp. 1, 32 rumen-fistulated Nellore steers (initial shrunk body weight [BW] = 355 ± 4.4 kg) were assigned to a randomized complete block design. Within block, animals were randomly assigned to one of four treatments: 1) forage-based diet without feed additives (CON), 2) CON diet plus 13 mg/kg of dry matter (DM) of NAR, 3) CON diet plus 20 mg/kg of DM of sodium LAS, or 4) CON diet plus 20 mg/kg of DM of VRM. No treatment effects were detected (P ≥ 0.32) for intake and apparent digestibility of nutrients. Steers fed NAR had the lowest (P ≤ 0.01) molar proportion of acetate on day 28, 56, and 112 vs. CON, LAS, and VRM steers, whereas acetate did not differ (P ≥ 0.25) between LAS, VRM, and CON steers from day 28 to 84. On day 112, steers fed LAS had a lower (P < 0.02) molar proportion of acetate vs. VRM and CON, whereas it did not differ between CON and VRM (P > 0.33). Steers receiving NAR had a greater (P ≤ 0.04) ruminal propionate vs. CON, LAS, and VRM, whereas LAS steers had greater (P < 0.04) propionate vs. CON and VRM steers on day 28 and 112, and it did not differ (P > 0.22) between CON and VRM. In Exp. 2, 160 Nellore bulls were blocked by initial shrunk BW (212 ± 3.1 kg) in a 140-d feedlot trial. Diets contained the same treatments used in Exp. 1. Bulls fed NAR had greater (P < 0.02) average daily gain (ADG) vs. CON and VRM, and similar (P = 0.17) ADG between NAR and LAS, whereas ADG did not differ (P > 0.28) between LAS, VRM, and CON bulls. A treatment effect was detected (P = 0.03) for dry matter intake, being greater in NAR vs. CON, LAS, and VRM bulls, and similar (P > 0.48) between CON, LAS, and VRM bulls. A tendency was detected (P = 0.09) for feed efficiency, which was greater (P < 0.02) in NAR bulls vs. CON and VRM, and similar (P = 0.36) between NAR and LAS bulls. From day 112 to 140, bulls receiving NAR were heavier (P < 0.03) vs. CON, LAS, and VRM bulls, but no differences were observed (P > 0.51) between CON, LAS, and VRM bulls. Collectively, ruminal fermentation profile and intake were impacted by NAR supplementation, which partially contributed to the enhanced performance of Nellore bulls receiving a forage-based diet.. Feed additives are nutritional tools that benefit dietary digestibility and nutrient utilization, alter ruminal fermentation routes, and improve cattle growth and efficiency, thus increasing productivity and profitability in beef cattle systems. Nonetheless, most of the current research focuses on supplementing feed additives in high-concentrate diets. Leaving a significant gap in understanding the influence of feed additives in cattle consuming forage-based diets, especially molecules capable of altering the fermentation process and, consequently, beef cattle performance. Therefore, this experiment aimed to evaluate the impacts of supplementing narasin (NAR), lasalocid (LAS), or virginiamycin (VRM) on rumen fermentation parameters, apparent nutrient digestibility, feed intake, and performance of Bos indicus Nellore cattle consuming a forage-based diet. Including commercially available feed additives into forage-based diets did not impact nutrient intake and digestibility of nutrients. The inclusion of NAR affected ruminal fermentation parameters toward propionate production, positively contributing to animal performance. Ruminal fermentation characteristics and animal growth were not impacted by dietary LAS and VRM, which could be attributed to the dose used in the current experiment, despite the manufacturer’s recommendation. This research provides insights into NAR as an important feed additive for forage-based beef cattle diets.

Topics: Animal Feed; Animals; Body Weight; Cattle; Diet; Dietary Supplements; Digestion; Fermentation; Lasalocid; Male; Propionates; Rumen

Dairy calf weaning is associated with ketone concentrations that exceed the levels occurring in adults, and weaning represents a potential energy loss that may be mitigated by ionophore supplementation. To assess the effects of weaning and ionophore supplementation on net nutrient flux across portal-drained viscera (PDV) tissues in dairy calves, concentrations of glucose, acetoacetate (ACAC), beta-hydroxybutyrate (BHBA), nonesterified fatty acids, volatile fatty acids, lactate, pyruvate, insulin, and glucagon and PDV flux rates were determined in Jersey bull calves (n = 19) at 35, 56, 84, and 112 d of age. Calves were randomly assigned at birth to either a commercial pelleted starter without (CON) or with lasalocid (TRT; 83 mg/kg of dry matter). Calves were fed only milk replacer from d 3 to 34 (d 3 to 20 = 454 g/d; d 21 to 34 = 568 g/d). After blood sampling on d 35, calves received replacer (d 35 to 41 = 454 g/d; d 42 to 48 = 227 g/d) and had free access to the CON or TRT starter, and from d 49 to 112 they received CON or TRT ad libitum. Catheters were implanted in the portal vein and in the mesenteric vein and artery between d 21 and 28. Blood flow was measured by continuous infusion of p-aminohippurate into the mesenteric vein. Six serial samples were taken at 30-min intervals from the arterial and portal vein catheters simultaneously. Portal blood flow increased with age but did not differ between CON and TRT calves. Glucose was released preweaning and was extracted postweaning by PDV, but was not affected by ionophore. The portal flux of nonesterified fatty acids was not different from zero during any of the 4 sample ages. Fluxes of ACAC and BHBA in CON and TRT calves went from no measurable flux preweaning to a postweaning PDV release that peaked at d 84, but the d-84 release of ACAC and BHBA was lower in TRT calves. The portal flux of volatile fatty acids increased with age, and PDV release of both butyrate and propionate was lower at d 84 in TRT than in CON calves. However, TRT calves had a greater PDV release of lactate on d 84, partially compensating for the lower release of propionate. Glucagon was greater in CON than in TRT calves at d 84 and could be a response to the elevated ketogenesis observed in CON calves during this period. Changes in the metabolic profile and nutrient flux of transition calves were demonstrated in response to weaning and ionophore supplementation. Inclusion of an ionophore appeared to moderate alimentary output at a

Topics: Animal Feed; Animals; Blood Flow Velocity; Body Weight; Cattle; Dairying; Dietary Supplements; Eating; Ionophores; Lasalocid; Male; Time Factors; Weaning

The objectives of this study were 1) to examine the interactive influence of a compensatory nutrition regimen and lasalocid supplementation on dairy heifer growth performance and 2) to document the extent to which compensatory growth sustains lactation potential over the first two lactation cycles. Twelve Holstein heifers, weighing an average of 160 kg (about 6 mo of age) were randomly assigned to treatments arranged in a 2 x 2 factorial design. Treatment variables were two dietary regimens (control and stair-step compensatory nutrition) and two levels of lasalocid (0 and 200 mg/d). The control heifers were fed a diet containing 12% crude protein (CP) and 2.35 Mcal of metabolizable energy (ME) per kilogram of dry matter. The stair-step compensatory nutrition heifers were subjected to a phased nutrition regimen and reared according to an alternating 3-2-4-3-4-2-mo schedule. The first stair-step (prepubertal phase) consisted of energy restriction [17% CP and 2.35 Mcal/kg of ME] for 3 mo followed by realimentation (12% CP and 3.05 Mcal/kg of ME) for 2 mo. The second step (puberty and breeding) consisted of energy restriction for 4 mo followed by realimentation for 3 mo. The third step (gestation period) was energy restriction for 4 mo concluding with realimentation for 2 mo. Dry matter intake of heifers during the restriction phase was limited to 70% of the control intake. Heifers were given ad libitum access to a high energy density diet during realimentation to allow compensatory development. Stair-step heifers supplemented with lasalocid had the highest efficiency of growth (body weight gain/dry matter intake), suggesting synergistic metabolism of lasalocid with compensatory growth action. Compensatory growth induced during the last trimester enhanced metabolic status by increasing circulating insulin and decreasing triglyceride levels. Heifers on the stair-step regimen had a significant increase in milk yield during the first (21%) and second (15%) lactation cycles. These results support our thesis that compensatory growth induced during an allometric growth phase improves mammary development and energy and protein metabolic status of dairy heifers.

Topics: Age Factors; Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Body Weight; Breeding; Cattle; Energy Intake; Female; Food Deprivation; Ionophores; Lactation; Lasalocid; Random Allocation

To determine the effects of dietary lasalocid and increased dietary fat on reproduction, multiparous Brahman cows (n = 68), body condition score (BCS) of 6.2 +/- 0.7 and BW of 500.9 +/- 42.6 kg, were randomly assigned within sex of calf to receive one of four rations. All treatment groups grazed Coastal bermudagrass overseeded with rye-ryegrass and were given ad libitum access to hay and water. The control (n = 17) group received 4.17 kg x d(-1) x cow(-1) of 4:1 corn:soybean meal. The rice bran (n = 17) group received 4.35 kg x d(-1) x cow(-1) of 3:1:1 corn:soybean meal:rice bran (5.2% dietary fat). The lasalocid (n = 17) group received the Control diet with the addition of 200 mg of lasalocid x d(-1) x cow(-1). The rice bran-lasalocid (n = 17) group received the rice bran diet with the addition of 200 mg of lasalocid x d(-1) x cow(-1). Diets were fed once daily from d 1 after parturition through the detection of first estrus. Weight and BCS of cows and BW of calves were recorded at 14-d intervals from d 1 after parturition through detection of first estrus and at weaning. Cows were bled on d 1, 3, 5, 7, and 14 and at weekly intervals until estrus and on d 7 and d 10 after estrus. Ovarian follicular populations were monitored by transrectal ultrasonography weekly from d 14 after parturition through detection of first estrus. Plasma 13-14-dihydro-15-ketoprostaglandin-F2alpha (PGFM) and progesterone (P4) concentrations were quantified using RIA. Concentrations of PGFM from d 1 to 7 and P4 concentrations on d 7 and 10 after estrus were not influenced (P > 0.10) by diet or sex of calf. Changes in BW and BCS were not affected (P > 0.10) by diet. The number of medium-sized follicles tended to be greater (P < 0.06) in Controls than in cows on lasalocid or rice bran + lasalocid treatments on d 21. Cumulative return to estrus with a functional corpus luteum by d 60 postpartum was greater (P < 0.02) in the rice bran (70.6%) and lasalocid groups (76.5%) than in Controls (52.9%) or the group given rice bran + lasalocid (25.0%). Normal first estrous cycles were less likely (P < 0.07) to be exhibited in cows given rice bran + lasalocid than in other groups. Intervals from calving to corpus luteum formation, functional corpus luteum, and first P4 > or = 1 ng/mL were longer (P < 0.02) in cows given rice bran + lasalocid than in other cows. Combining increased dietary fat (5.2%) with lasalocid lengthened the time to reproductively important events.

Topics: Animal Feed; Animals; Body Weight; Cattle; Dietary Fats; Estrus Detection; Female; Hormones; Ionophores; Lasalocid; Male; Oryza; Ovarian Follicle; Plant Oils; Postpartum Period; Pregnancy; Pregnancy, Animal; Random Allocation; Reproduction; Rice Bran Oil; Sex Factors

In Exp. 1, 72 Targhee lambs (initial BW 22.1+/-.3 kg) were used to determine the effects of energy source (alfalfa pasture vs limit-fed, all-concentrate) and ionophore addition on performance, visceral organ mass, and carcass characteristics. There were no differences (P > . 10) in ADG or gain/ feed due to ionophore supplementation. Lambs that grazed alfalfa had greater (P < .05) liver, omasum, abomasum, small intestine, cecum, and large intestine weights than did lambs fed the concentrate diet. Lambs fed the concentrate diet had greater (P < .01) hot carcass weights, larger (P < .01) loin eye areas, and greater (P < .001) dressing percentages than lambs that grazed alfalfa. In Exp. 2, lambs offered the concentrate diet had greater (P < .001) DM and OM digestibilities than lambs offered alfalfa (89.5 and 91.1 vs 72.4 and 74.2%, respectively). Apparent and true N digestibilities were greater (P < .001) for the concentrate diet than for alfalfa (90.9 and 101.7 vs 77.7 and 91.9%, respectively). Likewise, grams of N retained per day were twice as great (P < .001) with the concentrate diet than with alfalfa (14.9 vs 6.0 g/ d). The greater visceral organ mass and resulting increases in energy and protein requirements in lambs that grazed alfalfa were probably responsible for the lesser hot carcass weight and dressing percentage compared with lambs fed 100% concentrate.

Topics: Animal Feed; Animals; Body Weight; Dietary Supplements; Digestion; Energy Metabolism; Ionophores; Lasalocid; Medicago sativa; Nitrogen; Organ Size; Sheep; Viscera

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

Lasalocid and monensin are widely used to control coccidiosis in broilers, but not in turkey poults. Four feeding trials were conducted to determine the performance of turkey poults when these compounds were used singly or in combination with 100 ppm of furazolidone. Bodyweights and feed consumption were significantly depressed for five weeks after hatching by 150 ppm of lasalocid. Combining furazolidone with lasalocid ameliorated the toxic effect of lasalocid. Bodyweights were significantly depressed by 150 ppm of monensin in the fifth week after hatching, but there was no significant depression in feed consumption. Furazolidone exacerbated any toxic effects of monensin. Data indicate that monensin may be used safely at dosages greater than the recommended level of 60 to 99 ppm, but should not be used in combination with furazolidone.

Topics: Animal Feed; Animals; Bacterial Infections; Body Weight; Coccidiosis; Drinking; Drug Interactions; Eating; Furazolidone; Lasalocid; Male; Monensin; Poultry Diseases; Random Allocation; Turkeys

Two winter feeding trials (1985-86; 1986-87) were conducted to evaluate the productivity of gestating ewes fed lasalocid (L) and two supplement levels while grazing Montana winter range. Five hundred range ewes were randomized within age and breed each year and allotted to .15 or .23 kg hd-1.d-1 of a 20% CP supplement and either no L or L at 70 mg hd-1.d-1. Feed treatments began on 18 Dec. approximately 100 d before the first expected lambing date and continued for 84 d. Ewes fed .23 kg of supplement per day gained more (P less than .01) total weight (4.9 vs 4.0 kg) during the 84-d experiment and had higher (P less than .05) grease fleece weights (4.2 vs 4.0 kg) than those fed .15 kg of supplement. Lasalocid had no effect (P greater than .05) on ewe weight change or grease fleece weights. Supplement level had no effect (P greater than .05) on reproduction, lamb mortality and lamb performance. Ewes fed L had a greater (P less than .05) percentage of lambs born per ewe than those not fed L (120.7 vs 112.1%); lamb performance was similar (P greater than .05) between treatments. However, because a greater percentage of lambs were born per ewe starting the experiment, ewes fed L produced more (P less than .05) kilograms of weaned lamb than those not fed L (25.9 vs 23.4 kg). In conclusion, ewes fed L and grazing winter range weaned more kg of lamb than did controls because of an improved lambing percentage.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animal Feed; Animals; Animals, Newborn; Body Weight; Female; Food, Fortified; Lasalocid; Least-Squares Analysis; Pregnancy; Pregnancy, Animal; Random Allocation; Seasons; Sheep; Wool

The effects of ionophores on liver weight and function were determined in finishing steers (n = 24; avg weight 440 kg). Steers were group-fed one of three treatments (control, lasalocid or monensin at 33 mg/kg feed) for 46 d prior to slaughter. Three days prior to slaughter, blood was collected for the determination of serum Ca and Mg. At slaughter, the liver was removed, weighed, sampled, frozen in liquid nitrogen and subsequently analyzed for concentrations of carbohydrate metabolites and minerals. Liver weight (5.9 kg) was unaffected by treatment. Serum and hepatic Ca and Mg were not affected by ionophore treatment. Hepatic glycogen levels in steers fed ionophores were unaffected by treatment. Fructose 1,6-bisphosphate was 21% lower (P less than .10) in hepatic tissue of steers fed ionophores, whereas dihydroxyacetone phosphate was 15 to 37% greater in hepatic tissue of steers fed monensin (P less than .20) or lasalocid (P less than .10). Glyceraldehyde 3-phosphate was elevated more extensively by lasalocid than by monensin with increases of 72 (P less than .05) and 132% (P less than .001), respectively, over controls. Glycerol 3-phosphate levels were 37% (P less than .05) and 12% (NS) greater with these ionophores. Hepatic levels of pyruvate were elevated 12 (NS) to 36% (P less than .17) for monensin and lasalocid. Fructose 2,6-bisphosphate levels were 25% lower (P less than .25) in hepatic tissue of steers fed ionophores than in hepatic tissue from control steers. Other metabolites of carbohydrate metabolism in hepatic tissue were not altered appreciably. Changes in levels of intermediary metabolites of carbohydrate metabolism suggest alterations in hepatic carbohydrate metabolism favoring gluconeogenesis in steers fed ionophores.

Topics: Animals; Body Weight; Calcium; Carbohydrate Metabolism; Cattle; Ionophores; Lasalocid; Least-Squares Analysis; Liver; Liver Glycogen; Magnesium; Male; Monensin; Organ Size; Random Allocation

One hundred forty-three crossbred, fall-calving first-calf heifers were used to determine the effects of two levels of energy and two levels of lasalocid on cow-calf productivity. Diets fed for approximately 110 d prepartum were calculated to provide a daily intake of 15.3 (LE) or 18.0 (HE) Mcal ME; diets fed for approximately 130 d postpartum were calculated to provide a daily intake of 17.8 (LE) or 21.0 (HE) Mcal ME. Two supplements were fed with each energy level to provide a calculated 0 (C) or 200 mg.hd-1.d-1 lasalocid (L). Heifers fed HE gained .06 kg more (P = .08) per day prepartum than LE heifers. There was an interaction (P less than .05) between treatment and prepartum days on trial for heifer weight approximately 2 wk prepartum and body condition at calving. Energy had no effect on heifer weight at 2 wk prepartum or condition score at calving when estimated and compared at 90 d on trial. However, regression estimates for 130 d on trial showed that HE heifers would have been 19 kg heavier (P less than .001) and would have had .4 unit higher condition score (P less than .01) than LE heifers. Energy and lasalocid had no effect (P greater than .05) on hip height or pelvic area at calving or on calf birth weight, calving ease score or gestation length. Cows fed HE weighed 17 kg more (P less than .05) and had .5 unit higher (P less than .001) condition score than LE cows at approximately 130 d postpartum. Lasalocid had little effect on postpartum changes in weight or body condition. Lasalocid supplementation to the LE diet tended to increase milk production and calf weight, whereas supplementation to the HE diet did not. Feeding the LE diet decreased (P less than .05) cycling activity by 18 percentage points and decreased (P less than .01) overall pregnancy rate by 25 percentage points. Lasalocid had no influence on reproductive performance.

Topics: Animal Feed; Animals; Body Weight; Cattle; Energy Metabolism; Estrus; Female; Fertility; Lactation; Lasalocid; Postpartum Period; Pregnancy; Pregnancy, Animal

Two trials were conducted with 32 and 39 finishing Belgian white-red bulls, treated with anabolic agents during 55 to 60 days prior to slaughter. Xenobiotic androgens and estrogens, together with (Exp. I) or without progesterone (Exp. II) were injected at three-week intervals. Diets consisted of maize silage and 7.5 g concentrate daily per kg liveweight. Half of the animals within each experiment received an antibiotic for the entire fattening period lasting about 285 days. Lasalocid-sodium (Exp. I) and virginiamycin (Exp. II) were incorporated at 65 mg per kg concentrate. Anabolic agents improved average daily gain from 1.06 to 1.20 kg (P less than 0.10) and from 1.24 to 1.42 kg (P less than 0.05) respectively. In both trials steroidal growth promoters stimulated intake and improved feed efficiency (P less than 0.10). Feed antibiotics did not significantly affect daily gain during this short term finishing period. A reduced feed intake (P less than 0.05) and improved feed conversion were observed for lasalocid, while there was no difference for virginiamycin. Dry matter intake amounted to 80.5 and 76.3 g per kg metabolic weight and 9.02 and 8.41 kg per kg gain, respectively for control and lasalocid treated animals. The data were 79.6 and 80.3 g and 7.30 and 7.34 kg, respectively, for the experiment with virginiamycin. No significant interaction between anabolics and antibiotics was obtained with respect to gain and feed efficiency. Dressing percentage, carcass composition, carcass grading and meat traits were not affected by anabolic treatment or antibiotic supplementation.

Topics: Anabolic Agents; Androgens; Animal Feed; Animals; Body Weight; Cattle; Eating; Estrogens; Lasalocid; Male; Meat; Medroxyprogesterone; Medroxyprogesterone Acetate; Virginiamycin

The effect of lasalocid (140 mg . head-1 . d-1) on sow reproductive performance and subsequent piglet performance during lactation were examined in a trial that involved 114 sows. Treatments consisted of 1) control diet with no lasalocid during gestation and lactation; 2) lasalocid diet during gestation, control diet during lactation; 3) control diet during gestation and lasalocid diet during lactation; and 4) lasalocid diet during gestation and lactation. The addition of lasalocid either to gestation or lactation diets had no effect (P greater than .10) on sow weight gains or days to return to estrus postweaning. Milk protein percentages were similar (P greater than .10) for sows in all treatment groups for samples taken at 3, 7 and 14 d postfarrowing. Milk fat percentages were higher (P less than .05) in fall-bred sows at d 3 for Treatments 1, 3 and 4 than for Treatment 2 No significant differences (P less than .10) were observed for litter size at birth, 21 d postfarrowing or at weaning. Piglet weights at birth, 21 d and weaning were similar (P less than .10) among treatment groups. However, litter size and litter weight gains tended to be heavier at 21 d postfarrowing and at weaning for fall-bred sows fed lasalocid in either gestation and (or) lactation compared with those fed the control diet.

Topics: Animals; Animals, Newborn; Body Weight; Estrus; Female; Lactation; Lasalocid; Litter Size; Milk; Pregnancy; Pregnancy, Animal; Swine

Two experiments were conducted to quantify the effects of lasalocid on the performance and energy partitioning of cattle fed a 90% concentrate, barley-based diet. Experiment 1 utilized 100 Hereford heifers (initial weight 308 kg) fed diets containing no added ionophore, lasalocid added at 24, 36 or 54 mg/kg dry matter (DM), or monensin added at 33 mg/kg DM. In the 98-d trial, lasalocid-fed heifers gained an average of 1.35 kg daily, whereas control heifers gained 1.24 kg (P = .12). Heifers fed lasalocid (36 or 54 mg/kg DM), monensin, and the control diet required 6.2, 6.5 and 6.9 kg DM/kg gain, respectively (P greater than .1). Ionophores had no influence on carcass quality. In Exp. 2, four steers (616 kg) were fed the control or lasalocid diet (36 mg/kg DM) at daily feeding levels of 21, 44, 67 and 89 g DM/kg body weight.75; fecal, urinary, methane and heat losses were measured by total collection and indirect calorimetry methods. The proportion of digestible energy lost as methane averaged 7.5% for steers fed the control diet and 7.1% for the steers fed lasalocid (P less than .1). Lasalocid improved (P less than .05) the metabolizable energy (ME) density of the diet by 8, 8 and 5% at the 21, 44 and 67 g DM feeding levels. There was no difference (P greater than .1) between diets in ME density at the 89 g DM feeding level. The net energy for maintenance (NEm) value of the diet was increased (P less than .05) by 10 to 21% with lasalocid, whereas the net energy for gain (NEg) value was not affected. Average heat productions of the steers were increased (P less than .05) by 7% with lasalocid. The ME requirement for maintenance was estimated at 84 and 81 kcal/kg body weight.75 from linear regressions of energy retention and ME intake above maintenance for the control and lasalocid diets, respectively. Corresponding estimates using a semilog-linear method were 90 and 92. No differences (P greater than .1) in blood concentrations of insulin, glucagon or growth hormone were observed with the ionophore treatment. It was concluded that the main method by which lasalocid improved feed conversion was by increasing the ME density of the diet.

Topics: Animals; Body Weight; Cattle; Digestion; Energy Metabolism; Female; Lasalocid; Male

Twenty-two neonatal calves were assigned to a control or lasalocid-fed group and weaned at 3 wk of age. They were fed a prestarter diet from 3 d of age until they consumed 227 g/d and then a mixture of 227 g prestarter daily and starter diet in ad libitum amounts. The lasalocid-fed group received lasalocid in milk at 1 mg/kg body weight daily from 4 to 7 d and at .5 mg/kg body weight daily in milk and medicated prestarter diet (88 mg lasalocid/kg) during the 2nd wk. After 2 wk, lasalocid-fed calves were given medicated prestarter and starter (44 mg lasalocid/kg) diets. Four calves in each group were ruminally cannulated at 3 to 5 d of age, and ruminal contents were obtained at weekly intervals to monitor microbial activity. Rectal fecal samples were collected from all calves and examined for coccidial oocysts. Lasalocid-fed calves had a greater weekly feed intake and weight gain than control calves after 6 wk of age. Total ruminal volatile fatty acid concentrations were higher, but the acetate:propionate ratio was lower in lasalocid-fed calves than in control calves. Total viable anaerobic and amylolytic bacterial counts were higher in lasalocid-fed calves than in control calves. No significant treatment effect was found for ruminal NH3-N concentration or ruminal lasalocid-resistant, lactobacilli, lactate-utilizing, cellulolytic or methanogenic bacterial numbers. No evidence of coccidiosis was detected in either group. In general, lasalocid-fed calves had greater feed intake, weight gain and ruminal microbial activity than the calves fed no lasalocid in the diet.

Topics: Animals; Body Weight; Cattle; Fatty Acids, Volatile; Feces; Fermentation; Lasalocid; Male; Parasite Egg Count; Rumen; Weaning

1. The performance of 1680 male broiler chickens was measured from one to 42 d of age. They were given diets with three (125, 165 and 205 mEq/kg) electrolyte balances (sodium + potassium - chloride), two sources of added potassium (carbonate or sulphate) and two anticoccidial agents (90 mg/kg of either monensin or lasalocid). 2. The dietary treatments had no significant effects on the growth performance of broiler chickens in the starter phase. 3. In the finisher phase, the chickens given the diets containing lasalocid utilised food less efficiently that those given the diets containing monensin. 4. There were significant interactions between dietary electrolyte balance and source of added potassium on body weight gains and food:gain ratios in the finisher phase. In diets with an electrolyte balance of 205 mEq/kg, the inclusion of potassium sulphate instead of potassium carbonate increased body weight gains by 3.4% and reduced food:gain ratios by 4.6%. 5. The body weight gains of chickens given the finisher diets containing lasalocid and added potassium carbonate were reduced by 2.6% compared to those of chickens given the diets containing monensin or added potassium sulphate. 6. The litter moisture content was higher in pens with chickens on the diets with an electrolyte balance of 205 mEq/kg than on the diets with either 125 or 165 mEq/kg. Both lasalocid and potassium sulphate tended to increase the litter moisture content. 7. It may be concluded that the inclusion of 90 mg/kg of either monensin or lasalocid in broiler diets does not alter the balance of electrolytes required for optimum growth performance of broiler chickens.

Topics: Animals; Body Weight; Chickens; Lasalocid; Male; Monensin; Potassium; Sodium, Dietary

The activities of five anticoccidials were compared against Eimeria species in/of chickens, in controlled in vivo and in vitro laboratory studies. Two more recent and potent market entries (maduramicin and halofuginone) were compared with three older polyether antibiotic anticoccidials (monensin, lasalocid and salinomycin). Halofuginone, lasalocid, maduramicin, monensin and salinomycin were evaluated at 3, 125, 5, 120 and 66 ppm, respectively, of active drug in the diets. At these levels, all five drugs demonstrated significant activity against Eimeria tenella, E. maxima, E. necatrix, E. brunetti and E. acervulina (in vivo). Monensin was least effective against E. tenella, and one of the lesser efficacious drugs against E. necatrix, maduramicin, was least effective against E. maxima. In studies of single Eimeria species infections, comparable weight gains were noted for the drugs. In the mixed Eimeria species infections, however, birds treated with maduramicin had significantly higher weight gains than did birds medicated with monensin. Unlike in vivo potencies, titration in vitro indicated that monensin was most potent (active at 10(-6) mcg ml-1), and maduramicin and lasalocid least potent (inactive at less than or equal to 10(-3) mcg ml-1).

Topics: Animals; Anti-Bacterial Agents; Body Weight; Chickens; Coccidiosis; Coccidiostats; Eimeria; Female; Ionophores; Lactones; Lasalocid; Male; Monensin; Piperidines; Poultry Diseases; Pyrans; Quinazolines; Quinazolinones

An investigation involving 640 turkeys demonstrated that the inclusion of lasalocid continuously from day-old to 16 weeks of age, at levels up to 375 ppm in the feed, produced no adverse effects; furthermore, the inclusion of 125 ppm lasalocid in the feed was compatible with the administration of 250 ppm tiamulin in the drinking water continuously for five days to turkeys over the same age range.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Body Weight; Coccidiosis; Diterpenes; Drinking; Eating; Female; Lasalocid; Male; Organ Size; Poultry Diseases; Turkeys

We studied the effect of sulfadiomethoxine and ormetoprim (Rofenaid 40) in combination with lasalocid (Avatec) and monensin (Coban) on mortality, weight gain, and feed conversion of 2592 male broilers to 47 days of age. Four shuttle treatments were utilized: 1) monensin feeding for the entire trial; 2) sulfadimethoxine and ormetoprim feeding for the first 2 weeks, followed by lasalocid for the remainder of the trial; 3) sulfadimethoxine and ormetoprim feeding for the first 2 weeks, followed by monensin; and 4) sulfadimethoxine and ormetoprim feeding through week 3, then lasalocid for the remainder of the trial. No significant (P greater than .05) differences were observed in mortality among the four treatments. The combination of sulfadimethoxine and ormetoprim plus lasalocid significantly (P less than .01) improved weight gain and final body weight, but the length of time that sulfadimethoxine and ormetoprim were fed did not have any effect. Sulfadimethoxine and ormetoprim plus monensin treatment resulted in better feed conversion as compared with the other treatments.

Topics: Animals; Body Weight; Chickens; Lasalocid; Male; Monensin; Pyrimidines; Sulfadimethoxine

Two growth experiments were conducted to evaluate in broiler chicks the compatibility between lasalocid medication in the feed (at 90 or 125 ppm) and a long-term administration of chloramphenicol either via the feed (500 ppm) or via the drinking water (500 mg/liter). The simultaneous administration of lasalocid and chloramphenicol generally caused severe growth depression, decreased feed intake and impaired feed conversion. Several chicks showed evident symptoms of intoxication, such as ataxia, leg weakness and paralysis. The development and frequency of these symptoms were dependent on the dosage of lasalocid and on the duration of the simultaneous administration. Biochemical examinations (Experiment 2) revealed in the affected chicks significant changes in several parameters, in particular a markedly increased activity of creatine kinase and GOT in the plasma. It confirmed that the observed leg weakness and paralysis were caused by myodegeneration.

Topics: Animal Feed; Animals; Aspartate Aminotransferases; Ataxia; Body Weight; Chickens; Chloramphenicol; Creatine Kinase; Drug Incompatibility; Drug Therapy, Combination; Eating; Female; Lasalocid; Male; Paralysis; Poultry Diseases

Two trials were conducted to characterize the differences in utilization of dry-rolled and steam-flaked corn in a growing-finishing diet for feedlot cattle supplemented with and without ionophores. Ionophore treatments were: 1) no ionophore, 2) 33 mg/kg monensin sodium plus 11 mg/kg tylosin and 3) 33 mg/kg lasalocid sodium. In trial 1, treatment effects on feedlot performance were evaluated in a 239-d growing-finishing trial involving 180 crossbred steers (approximately 25% Brahman with the remainder represented by Hereford, Angus, Shorthorn and Charolais breeds in various proportions) with an average initial weight of 153 kg. In trial 2, treatment effects on characteristics of digestion were evaluated using six steers of similar breeding and background to those used in trial 1, with cannulas in the rumen and proximal duodenum. There were no interactions between corn processing and ionophore supplementation (P greater than .20). Average daily gain was not affected by steam-flaking as opposed to dry-rolling, however, feed intake was decreased 5.4% and feed conversion was improved 6.8% (P less than .01). Steam-flaking increased the estimated net energy value of the diet 7.7% and 8.5% for maintenance and gain, respectively (P less than .01). Steam-flaking increased the digestibility of starch 6.6% (P less than .01). Steam-flaking increased ruminal molar concentrations of propionate and decreased acetate:propionate ratio and estimated methane production (P less than .10). Both monensin-tylosin and lasalocid resulted in reduced feed intake (12.3 and 6.5%, respectively, P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animal Feed; Animals; Body Weight; Cattle; Digestion; Lasalocid; Leucomycins; Male; Monensin; Nutritive Value; Zea mays

Three experiments were conducted to study the effects of lasalocid level on performance, intake, digestibility, ruminal fermentation and fluid flow of beef cattle grazing dormant, tallgrass prairie. In Exp. 1, 120 pregnant, mature beef cows of primarily Hereford breeding (avg wt = 471 kg) were randomly assigned to received 0, 100, 200 or 300 mg lasalocid X head-1 X d-1 in 1.82 kg supplement. Weight changes at 30, 60 or 90 d, condition score change and calf birth weight were not affected (P greater than .10) by lasalocid level. In Exp. 2, estimates of intake and digestibility were obtained with 40 pregnant, mature Hereford cows (avg wt = 474 kg) and 12 esophageal-cannulated, Hereford X Angus steers (avg wt = 225 kg), using Yb and indigestible acid detergent fiber as markers for fecal output and digestibility, respectively. Levels of lasalocid provided to cows and steers were similar, on a body weight (BW) basis, to those in Exp. 1 and corresponded to approximately 0, .22, .44 or .66 mg lasalocid/kg BW. Total diet and forage organic matter digestibility for beef cows decreased (P less than .01) at the .22 mg/kg BW level, but increased at the .44 and .66 mg/kg BW levels. Organic matter intake was not influenced (P greater than .10) by lasalocid addition. In Exp. 3, 16 ruminal-cannulated, Hereford X Angus steers (avg wt = 227 kg) were given the same lasalocid dosages per kg BW as in Exp. 2, and were used to study the effects of lasalocid on ruminal fermentation and fluid flow characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animal Feed; Animals; Body Weight; Cattle; Digestion; Eating; Female; Fermentation; Lasalocid; Pregnancy; Rumen

Thirty Angus steers averaging 357 kg were used to: 1) determine the effect of feeding lasalocid (33 mg/kg diet) on mineral metabolism and 2) determine the effects of varying dietary sodium (Na) and potassium (K) on finishing steers fed lasalocid. Treatments consisted of: 1) control (.25% Na, .5% K); 2) lasalocid (.05% Na, .5% K); 3) lasalocid (.25% Na, .5% K); 4) lasalocid (.05% Na, 1.4% K) and 5) lasalocid (.25% Na, 1.4% K). Ruminal fluid and blood samples were collected on d 28 and 90 of the 102-d study. Gain and feed conversion tended to be higher for steers fed lasalocid with the exception of the .05% Na, 1.4% K treatment. Control steers had lower (P less than .05) erythrocyte K concentrations, reduced (P less than .05) soluble concentrations of magnesium and copper in ruminal fluid and decreased plasma concentrations of zinc (P less than .05) and phosphorus (P less than .10) at 90 d compared with steers fed lasalocid and similar concentrations of Na (.25%) and K (.5%). Increasing dietary Na from .05 to .25% in the presence of lasalocid increased (P less than (P less than .05) molar proportion of ruminal acetate at 28 and 90 d reduced (P less than .05) propionate at 90 d. Increasing K from .5 to 1.4% decreased (P less than .01) soluble Na and increased (P less than .01) soluble K concentrations in ruminal fluid. Steers fed lasalocid (.25% Na, .5% K) had lower concentrations of K (P less than .10) and zinc (P less than .10) in liver than control steers. Sodium and K level also affected tissue concentrations of certain minerals. Results suggest that dietary Na and K influence mineral metabolism and that dietary Na affects ruminal molar proportion of acetate in cattle fed lasalocid.

Topics: Animals; Body Weight; Cattle; Diet; Fatty Acids, Volatile; Lasalocid; Male; Minerals; Potassium; Rumen; Sodium

Fifty fall-weaned heifers with initial weights of 209 kg (yr 1) and 222 kg (yr 2) were used to determine effects of lasalocid on weight gains, forage intake and ruminal fermentation of stocker cattle grazing winter wheat pasture. The heifers grazed a single wheat pasture for about 100 d each year, and were individually fed 1.06 kg of supplement (6 d/wk) pro-rated to supply 0, 100 or 200 mg lasalocid.head-1.d-1. Also, eight mature Hereford steers with large rumen cannula were used to evaluate further effects of lasalocid (0 or 300 mg) on ruminal fermentation during two grazing periods (immature and mature wheat forage) of yr 2 and an additional third year. Daily gains of heifers fed 200 mg lasalocid/d were .11 kg greater (P less than .05) than those of heifers fed 0 or 100 mg lasalocid/d. One hundred milligrams lasalocid did not increase weight gains. Digestibilities of forage dry matter (DM) and organic matter (OM) were similar (P greater than .05) among treatments, and lasalocid did not affect (P greater than .10) forage intake. Ruminal ammonia concentrations (10.57, 15.22 and 17.81 mg/dl +/- 1.71) were increased (P less than .05) by both levels of lasalocid in yr 1, but differences among treatment means of 8.32, 11.95 and 11.66 (SE +/- 1.44) were not significant in yr 2. Lasalocid did not consistently affect total volatile fatty acids concentrations. The acetic:propionic acid ratios in heifers were not different (P greater than .05) among treatments, but were decreased (P less than .10) by lasalocid in cannulated steers.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animal Feed; Animals; Body Weight; Cattle; Eating; Female; Fermentation; Lasalocid; Rumen; Triticum

Forty-eight second, third and fourth parity crossbred sows were randomly allotted to four dietary treatments: corn:alfalfa-orchardgrass hay (46%; CH); CH plus lasalocid (CHL); corn-soybean meal (CS) or CS plus lasalocid (CSL). Sows were fed these diets through two successive gestations with dietary treatment initiated at 35 d post-coitum and continued until parturition. To equalize daily metabolizable energy intake (6.6 Mcal/sow), 2.64 kg of CH and CHL diets and 1.86 kg of CS and CSL diets were fed. Lasalocid intake was 130 mg X sow-1 X d-1. Sows were weighed and backfat measurements were taken at 35 and 109 d of gestation. Sows also were weighed 14 d postpartum. A 14% crude protein corn-soybean meal diet was fed ad libitum to all sows during lactation and feed intake was recorded. Colostrum samples were obtained within 4 h of farrowing. All live piglets were weighed at birth and 14 d of age. There were no significant differences among dietary treatments in number of live piglets born, piglet birth weight, piglet weight at 14 d of age or sow rebreeding efficiency. Sows fed CHL and CSL diets had more (P less than .12) live piglets at 14 d postpartum and lower (P less than .03) total fat in colostrum than did CH- and CS-fed sows. Alfalfa-orchardgrass hay feeding resulted in less (P less than .04) backfat deposition during gestation, more (P less than .04) weight loss from 109 d postcoitum to 14 d postpartum and increased (P less than .002) feed consumption during lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adipose Tissue; Animal Feed; Animals; Birth Weight; Body Weight; Colostrum; Fatty Acids; Female; Fetal Death; Lactation; Lasalocid; Lipids; Litter Size; Pregnancy; Pregnancy, Animal; Swine

The effects of lasalocid on fall-calving beef cows were examined in a 196-d trial that began October 12, 1983. Forty-two crossbred cow-calf pairs were stratified to six groups by breed, calving date and sex of calf. Three replications of each of two treatments, 0 and 200 mg lasalocid X head-1 X d-1, were used. The cows were fed a combination of haylage and grass hay ad libitum. The cow-calf pairs were allowed access to pasture at all times, except during the breeding season. At this time they were kept in confinement to facilitate heat detection and artificial insemination. Cow weight changes and body condition (0 = very thin, 9 = very fat) were unaffected (P greater than .10) by feeding lasalocid to the cows. Twelve-hour milk production per cow, percent fat and percent protein were each determined three times during the trial. A slight increase in milk yield was observed in treated cows (P greater than .10). Percent milk fat and protein were also unaffected by treatment (P greater than .10). Lasalocid supplementation of cows did not affect calf gain or 205-d adjusted weaning weight (P greater than .10). Average days open was evaluated for the cows. There were no differences between treatments for actual average days open (P greater than .10). No detrimental effects were observed in long-term feeding of lasalocid to fall-calving beef cows.

Topics: Animals; Body Weight; Cattle; Estrus; Female; Lactation; Lasalocid; Pregnancy; Seasons

The following conclusions are made from an introductory investigation on the use of the coccidiostat lasalocid on 11 production farms of an integrated broiler production organisation. In terms of the incidence of sub-clinical coccidiosis, no significant difference was found between the previous use of monensin and the use of lasalocid during the investigation. However, the incidence of coccidiosis decreased with the introduction of lasalocid. Despite the fact that on some farms sub-clinical coccidiosis was diagnosed, the production performance clearly improved with lasalocid. EBI figures significantly increased from 163.6 to 172.5. During the investigation, in which approximately 220,000 broilers were involved, litter quality did not differ from that of previous crops in which monensin had been used. Feathering of the broilers in the trial crops in which lasalocid was used was similar to that of previous crops.

Topics: Animals; Body Weight; Chickens; Coccidiosis; Eimeria; Feathers; Furans; Ionophores; Lasalocid; Poultry Diseases

Two, 7-week floor pen experiments were conducted consecutively with male broilers and then female broilers to determine the effects of feeding salinomycin (60 ppm), monensin (99 ppm), or lasalocid (125 ppm) at the following three levels of dietary protein: 1) that which meets National Research Council specifications (NRC, 1977), 2) that level deficient in sulfur amino acids (SAA), or 3) that deficient in protein. Group body weights, feed intake, and water consumption were noted at 28 and 49 days of age with feed efficiency and overall mortalities determined. Reducing SAA resulted in depressed (P less than .05) body weights at 7 weeks in both experiments, whereas deficient protein reduced (P less than .05) growth, feed efficiency, and water consumption. Generally, inclusion of coccidiostats in the diet did not significantly hinder growth or feed efficiency. Feeding of coccidiostats in combination with the low protein diet did not produce additional anorexigenic effects. Although a significant lasalocid SAA-sparing effect was not observed, diet X coccidiostat interactions (P less than .05) were apparent and attributable to an apparent "protein-sparing" effect upon body weight gain when salinomycin was fed in combination with the low protein diet. Lasalocid increased water consumption (P less than .05) relative to monensin in the female broilers.

Topics: Amino Acids, Sulfur; Animals; Body Weight; Chickens; Coccidiostats; Dietary Proteins; Drinking; Female; Food Additives; Lasalocid; Male; Monensin; Mortality; Pyrans; Sex Factors

Twenty-four half-sib Brahman bulls (171 to 276 d of age; 140.9 to 243.2 kg) were paired by age and weight and randomly allotted to one of two treatment groups (12 bulls/treatment) with two replicates (six bulls/replicate). Control treatment (C) was a 4:1 corn (IFN 4-02-931):cotton-seed meal (IFN 3-01-621) diet fed at 1% of the average body weight plus Coastal bermudagrass hay (IFN 1-00-716) ad libitum. Lasalocid treatment (L) was the control diet with the addition of 200 mg lasalocid X head-1 X d-1. Lasalocid resulted in lower acetate and butyrate with higher propionate and no change in total ruminal volatile fatty acids. Lasalocid-fed bulls tended to gain more weight (L = 153.6 +/- 8.5 kg, C = 138.4 +/- 7.9 kg; P less than .08), tended to have a greater average daily gain (ADG; L = .78 +/- .05 kg/d, C = .71 +/- .04 kg/d; P less than .09) and had greater feed conversion (11.5% less feed/kg gain) than did the control bulls. Lasalocid did not affect bull height (HT), weight:height ratio, length (LE) or heart girth (HG) at any time tested during puberal development. Lasalocid bulls exhibited a greater increase in HG through 175 d on treatment (L = 27.6 +/- 1.0 cm, C = 24.3 +/- 1.8 cm; P less than .05) and through first detected sperm (FS) in an ejaculate (L = 30.1 +/- 2.2 cm, C = 26.1 +/- 1.4 cm; P less than .05), but the increase in HG from the start of the trial through puberty was not different between treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Body Weight; Cattle; Fatty Acids, Volatile; Lasalocid; Male; Rumen; Scrotum; Sexual Maturation; Spermatozoa; Testis

The rate of feather growth was measured in Hubbard X Hubbard broilers given monensin, salinomycin, or lasalocid for 8 weeks in floor pens. Chicks were given a nutritionally adequate diet. Feathers on male chicks were shorter at 10 days of age but grew faster than those on female chicks. Male chicks had longer feathers than female chicks after 31 days of age. Back feather scores were similar in male and female chicks at 52 days of age. Dietary ionophores had no effect on the rate of feather growth or the back feather coverage under the condition of this study.

Topics: Animals; Body Weight; Chickens; Coccidiostats; Feathers; Female; Food Additives; Lasalocid; Male; Monensin; Pyrans; Sex Factors

The effect of restricted medication with lasalocid sodium on the development of acquired immunity against Eimeria tenella was evaluated. The medication was allowed for all or part of 6-day test period (one day before until 4 days after infection). The parameters used for such evaluations were lesion score, caecal, bursal and splenic weights. The optimum treatment time for the drug was clearly indicated by lesion score which was very low when the medication was initiated 1 day before until 1 day after inoculation, but only partly effective if given on Day 2 post-inoculation. The challenge with higher doses on 14th day of immunizing infection revealed a reverse picture where the higher lesions were recorded by the groups where medication was started earlier than the delayed treatment groups. This indicates partial interference with the development of immunity in the earlier treatment groups. Birds treated on Day 4 p.i. were not significantly different (P less than 0.05) from the infected unmedicated control group, suggesting no interference in acquired immunity. A correlation was noticed between day of treatment, the lesion score and weight gain of the caecum as well as the spleen. After both immunizing and challenge infections, the bursa did not show any significant variation in weight, whereas the weight of the spleen did vary. The infected unmedicated group and the delayed-treatment groups had a comparatively higher splenic weight than the uninfected unmedicated group of birds.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Body Weight; Bursa of Fabricius; Cecum; Chickens; Coccidiosis; Eimeria; Immunity; Lasalocid; Male; Organ Size; Poultry Diseases; Spleen

Seventy-two growing steers were used in a 126-d study to determine the influence of varying levels of lasalocid on performance, ruminal and serum characteristics of animals grazing pasture. Treatments consisted of: 1) control; 2) 200 mg lasalocid/d and 3) 300 mg lasalocid/d. Each treatment was replicated three times and each replicate of eight steers was maintained on 3.0 ha of pasture. Pastures consisted of a mixture of tall fescue, orchard grass and ladino clover. In addition to pasture, each replicate of steers was group fed ground corn at a rate of .91 kg X head-1 X d-1 with the lasalocid incorporated into the grain. Average daily gains were .50, .60 and .57 kg, respectively, for steers on the control, and for the 200 and 300 mg lasalocid treatments, which differed (P less than .05) from controls. Ruminal acetate (mol/100 mol) was lower (P less than .05) in steers fed lasalocid at 28 d, but similar for all treatments at 56 and 112 d. Molar proportion of propionate was higher (P less than .05) and butyrate and valerate were lower (P less than .10) in rumen fluid of steers receiving 200 or 300 mg/d of lasalocid. Plasma glucose concentrations were similar for controls and steers receiving 200 mg lasalocid/d, but higher (P less than .05) in steers fed 300 mg lasalocid/d. Serum Mg concentrations were lower (P less than .01) in steers receiving lasalocid. Potassium concentrations in serum were slightly lower (P less than .01) in animals fed lasalocid at 112 d, but not at 28 or 56 d.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Blood Glucose; Body Weight; Calcium; Cattle; Fatty Acids, Volatile; Food Additives; Lasalocid; Magnesium; Male; Minerals; Potassium; Rumen; Sodium

Protein supplements having either a high (soybean meal, SBM) or low (escape protein, EP) extent of ruminal N degradability with or without lasalocid (L) were evaluated in digestion and growth trials. The SBM supplement included soybean meal while EP was a combination of dehydrated alfalfa and distillers dried grains. Nitrogen digestibility of SBM supplements was consistently higher than EP supplements when evaluated with two lamb trials. Digestibility of N was improved 8% in trial one (64.9 vs 60.3%) and 27% in trial two (66.3 vs 52.3%) with SBM vs EP. The addition of L to the supplements improved N digestibility by 6% in trial one (64.5 vs 60.6%) and 13% in trial two (62.9 vs 55.7%). No interactions between protein source and L were measured in either trial. Dry matter digestibility was not changed by protein source or L in either trial. Rumen propionate was increased and acetate to propionate ratio decreased when L was fed. Plasma urea N was lower over a 24 h sampling period when lambs were fed EP supplements compared with SBM supplements (11.07 vs 16.44 mg/100 ml); however, L did not appear to consistently alter the values. When steers were supplemented with the same protein sources during a 105-d winter pasture trial daily gains were not affected (P greater than .10) by either protein source or L (.429, .495, .476 and .514 kg/d for SBM, SBM+L, EP and EP+L, respectively) although numerically there did not appear to be main effect improvements due to EP and L.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Blood Urea Nitrogen; Body Weight; Cattle; Dietary Proteins; Digestion; Fatty Acids, Volatile; Food Additives; Lasalocid; Male; Nitrogen; Rumen; Sheep

Monensin, lasalocid, salinomycin, nicarbazin, halofuginone, or arprinocid were fed to 1-week-old male broiler chicks at recommended levels and 1.5, 2, 2.5, and 3 times the recommended level, for 3 weeks. Pair-feeding experiments also were conducted to investigate the extent that growth depression with medicated diets could be attributed to the drop in feed consumption. At the recommended level of drugs, growth and feed conversion were not significantly affected. At elevated drug levels, performance was impaired; the adverse effects of drugs became more pronounced with increasing the concentrations in the diets. Weight gain was significantly depressed at 1.5X with arprinocid, halofuginone, and salinomycin, at 1 to 2X with monensin, at 2X with lasalocid, and at 2.5X with nicarbazin. Feed conversion, however, was adversely affected by 2X with halofuginone or 2.5X with salinomycin, nicarbazin, arprinocid, monensin, or lasalocid. The results of the pair-feeding experiments with 2 to 3 times drug levels indicated that most of the growth depression with medicated diets could be attributed to reduced feed consumption, but all drugs except arprinocid caused some additional growth depression.

Topics: Adenine; Animal Feed; Animals; Body Weight; Chickens; Coccidiostats; Growth; Lasalocid; Male; Monensin; Nicarbazin; Piperidines; Quinazolines; Quinazolinones

Piglets which were early-weaned at the age of 21.7 days and experimentally monoinfected with oocysts of Isospora suis showed distinct reductions in zootechnical criteria during an experimental period of 4 weeks. The daily liveweight gains in the infected piglets (group B) was 19.7% lower than in the control group A, which was free of Coccidia. Comparative photographs with the REM showed serious lesions in the small intestine of infected piglets, which are thought to be mainly responsible for the reduced productivity. The application of 150 mg Lasalocid per kg of total feed to infected piglets caused the rate of weight gain to attain the same values as the noninfected controls (group A). Piglets receiving Lasalocid treatment passed oocysts with the faeces which were infectious. On the other hand, infected piglets which were treated with 6 mg Halofuginone per kg of total feed did not contain any oocysts in the faeces. Despite having a higher liveweight at the beginning of the experiment, this group only gained as much liveweight as the infected piglets (group B). This depression in liveweight gains could be explained by the significantly reduced uptake of feed, which was 21.1% lower than in the controls (group A). 6 weeks after the first infection, a re-infection resulted in the appearance of oocysts in the faeces of the piglets which had been treated with Halofuginone. On the other hand, the animals treated with Lasalocid had developed an efficient immunity to Isospora suis.

Topics: Animals; Body Weight; Coccidiosis; Feces; Isospora; Lasalocid; Piperidines; Quinazolines; Quinazolinones; Swine; Weaning

Lasalocid at 25 mg/kg of feed was highly effective in reducing numbers of oocysts in feces of naturally infected ewes and lambs. Treated ewes were fed lasalocid-medicated feed before and after parturition, and the 17 lambs from these ewes also were fed medicated feed gained 5.26 kg more (P less than 0.05) than did the 17 nontreated lambs from nontreated ewes. Naturally infected lambs maintained in semiconfinement acquired coccidia infections between 23 and 64 (mean of 38) days after birth. A coccidiostat given before and during the time coccidia-naive lambs were first exposed to coccidia was necessary to achieve the greatest production response to treatment. When naturally infected feeder lambs (30.9 kg) maintained in semiconfinement were fed lasalocid-medicated feed at 25 mg/kg of feed or unmedicated feed for 91 days, no significant difference (P greater than 0.05) in rate or efficiency of gain was detected, even though lasalocid was highly effective against coccidia.

Topics: Administration, Oral; Animal Feed; Animals; Body Weight; Coccidiosis; Female; Lasalocid; Pregnancy; Sheep; Sheep Diseases

Early weaned male crossbred lambs (n = 90) with an average weight of 14 kg were used in 6 groups to evaluate the efficacy of monensin (22 mg/g of feed) and lasalocid (12.5, 25, 50, and 100 mg/kg of feed) on naturally occurring coccidiosis. Average 24-hour oocyst output at the start of the experiment ranged from 5.7 x 10(6) to 156.7 x 10(6) for monensin-treated and 100-mg lasalocid-treated groups, respectively. Monensin and lasalocid were effective against Eimeria ninakohlyakimovae of E ahsata. To day 103, body weight gains were similar for the 4 groups fed lasalocid (336 g/day) and averaged 6% higher (P greater than 0.05) than did gains in control and monensin-treated lambs. Feed efficacy averaged 9% higher (P less than 0.05) for lambs fed 25, 50, and 100 mg of lasalocid/kg of feed and 7% higher (P greater than 0.05) for lambs fed monensin and 12.5 mg of lasalocid/kg of feed. There were no treatment effects on digestibility, although lasalocid tended to increase (P greater than 0.05) crude protein digestibility (values were higher on day 76 than on day 28). Lasalocid and monensin were potent manipulators of rumen fermentation. Increasing the amount of lasalocid in the feed was associated with successive increases (P less than 0.05) in molar proportions of propionic acid and decreases (P less than 0.05) in acetic acid. Lasalocid and monensin controlled naturally occurring coccidiosis and improved performance in early weaned lambs (45 days old) under feedlot conditions.

Topics: Administration, Oral; Animal Feed; Animals; Body Weight; Coccidiosis; Fatty Acids, Volatile; Fermentation; Furans; Lasalocid; Monensin; Rumen; Sheep; Sheep Diseases

One growth and two finishing trials were conducted with beef steers to compare lasalocid sodium and monensin sodium. Pure lasalocid, mycelia-cake lasalocid and monensin, each added individually to commercial protein supplement blocks at 880 mg/kg, depressed (P greater than .05) block intake so that approximately 100 mg of each additive were consumed daily by each animal. Daily gain, feed intake and feed efficiency for steers receiving blocks containing additives did not differ from the corresponding measures for steers receiving control blocks. No differences were observed in diet dry matter digestibility, as determined with acid-insoluble ash as an internal marker. Both forms of lasalocid and monensin reduced (P greater than .05) the incidence and concentration of coccidia oocysts. By day 40, only one steer on each of the additive treatments was shedding oocysts (4.2% of additive-supplemented animals), compared with 41.5% of the control steers. During trial 2, steers fed pure lasalocid gained faster and more efficiently (P greater than .05) than those fed the mycelia-cake lasalocid, monensin or control diets. The improvement in feed efficiency over the control value was 10.0, 3.4 and 4.0% with pure lasalocid, mycelia-cake lasalocid and monensin, respectively (P greater than .05). Steers fed mycelia-cake lasalocid had higher (P greater than .05) dressing percentages than those fed pure lasalocid or monensin. Dressing percentage was the only carcass measurement affected. In trial 3, lasalocid at 30 and 45 g/ton and monensin at 30 g/ton improved (P greater than .05) feed efficiency by 7.5, 11.0 and 8.2%, respectively. No significant differences in incidence or concentration of oocysts were observed between treatment groups in trial 3, probably because steers were in slatted floor pens.

Topics: Animal Feed; Animals; Body Weight; Cattle; Cattle Diseases; Coccidia; Coccidiosis; Feces; Food Additives; Furans; Lasalocid; Male; Monensin; Parasite Egg Count

Three polyether, ionophorous anticoccidial drugs were fed to broiler chickens in floor pens for 5 or 6 weeks, then withdrawn for 2 weeks or 1 week, respectively. With monensin and salinomycin there was evidence of increased feed consumption and compensatory growth during the first week, but not the second week, after drug withdrawal. There was no evidence of compensatory growth in birds fed lasalocid. Final weights were best in birds fed lasalocid and salinomycin in comparison with unmedicated controls and birds fed monensin. There was evidence of increased feed consumption and compensatory growth in some treatments in which birds weighed more than controls prior to drug withdrawal.

Topics: Animals; Antibodies; Body Weight; Chickens; Eating; Furans; Ionophores; Lasalocid; Monensin; Pyrans

A field study was conducted from April through June of 1976 to determine whether coccidial infections adversely affect the growth and survivability of young mink. Two anticoccidials, lasalocid (62 mg/kg of feed) and an antibiotic-sulfonamide preparation (220 mg/kg of feed), were incorporated into a standard pelleted ration. Comparisons of weight gains, mortality, and oocyst numbers were made between control and treated groups. Treatment reduced mortality (P < 0.001) but did not significantly affect weight gains. The antibiotic-sulfonamide preparation and, to a lesser extent lasalocid, reduced oocyst discharge. Increased oocyst shedding was detected among adult female mink from parturition to weaning of their kits.

Topics: Animals; Body Weight; Coccidiosis; Feces; Female; Lasalocid; Mink; Pregnancy; Sulfonamides

Lasalocid and monensin were incorporated into pelleted feed and evaluated as anticoccidials in confinement-reared lambs from weaning to market weight. A total of 69 lambs were allotted to 3 equal groups that received unmedicated feed (100 mg/kg of food) or monensin-medicated feed (17 to 33 mg/kg). Each lamb was inoculated orally with a suspension of 24,000 oocysts (Eimeria spp) 24 and 52 days after the start of the experiment. Lasalocid and monensin were highly effective (greater than 99%) in eliminating oocysts of 5 species of ovine coccidia used in the inoculum. Treated lambs gained an average of 6 kg more weight (P less than 0.05) per animal than the untreated control lambs and consumed significantly (P less than 0.05) less feed for each kilogram gained. No statistical differences existed between treated groups (P greater than 0.05).

Topics: Animals; Anti-Bacterial Agents; Body Weight; Coccidiosis; Feces; Lasalocid; Monensin; Sheep; Sheep Diseases

Topics: Animals; Body Weight; Cattle; Cattle Diseases; Coccidiosis; Lasalocid

Lasalocid was tested at graded feed concentrations in controlled battery experiments against single and mixed Eimeria species infections in 2-week-old turykey poults. Eimeria meleagrimitis, E. gallopavonis, E. adenoeides, and E. dispersa infected poults medicated with lasalocid at concentrations of 0.15, .0125, .01, .0075, and .005% were heavier, converted feed more efficiently, showed lower lesion scores (ADI), shed fewer oocysts, and showed reduced or no mortality as compared to the infected, unmedicated controls. Lasalocid activity was similar against the few field isolates tested. Lasalocid responses were dose related, the higher the concentration, the greater the effect. The optimum dose level in these battery studies was approximately .0125%. Lasalocid fed at two times the optimum dose level to poults for a four week period did not have any adverse effect on growth or feed conversion performance.

Topics: Animals; Body Weight; Coccidiosis; Lasalocid; Monensin; Poultry Diseases; Turkeys

Lonomycin (TM-481, SQ 12,525) at various concentrations in the feed was tested in controlled battery experiments against laboratory strains of single and mixed Eimeria species infections. The experimental results indicated that lonomycin at doses of .003125, .00625, or .0125% demonstrated a high degree of anticoccidial activity by preventing or reducing mortality, reducing fecal dropping scores, and allowing for normal or near-normal weight gains against single and mixed infections of 5 major pathogenic species, E. acervulina, E. brunetti, E. maxima, E. necatrix, and E. tenella. Lonomycin, at these same dosages, was highly effective against a recent field isolate obtained from a flock previously fed monensin. These studies involving 7 trials totaling 1,680 broiler chicks, have demonstrated that lonomycin at levels of .003125 to .0125% (dependent on species of Eimeria) in the feed is an effective aid in the control of avian coccidiosis in broiler chickens.

Topics: Administration, Oral; Animal Feed; Animals; Anti-Bacterial Agents; Body Weight; Chickens; Coccidiosis; Coccidiostats; Ethers; Female; Lasalocid; Male; Monensin; Nigericin; Poultry Diseases