estradiol-3-benzoate and Weight-Gain

Two studies evaluated growth promoting effects of implant pellets (IP), each containing 3.5 mg estradiol benzoate (EB) and 25 mg trenbolone acetate (TBA), to which a polymeric, porous coating was applied. Trial 1 evaluated performance of heifers (n = 70/treatment, initial BW = 188 ± 2.2 kg) and steers (n = 70/treatment, initial BW = 194 ± 2.2 kg) implanted subcutaneously in the ear with 0 (SC), 2 (2IP), 4 (4IP), or 6 (6IP) pellets that delivered EB/TBA (mg/mg) doses of 0/0, 7/50, 14/100, and 21/150, respectively, over grazing periods of 202 d (heifers) or 203 d (steers). Animals received experimental treatments on d 0 and over the grazing period were managed as single groups by sex in a rotational grazing system. When pasture forage availability became limited, cattle were supplemented with preserved forage but not concentrate supplements. Weight gains by heifers treated with 2IP, 4IP, and 6IP were greater (P < 0.05) than SC heifers but not different from each other. Weight gains by steers treated with 2IP, 4IP, and 6IP were greater than SC steers (P < 0.05), and ADG by steers treated with 6IP was greater (P < 0.05) than steers given 2IP or 4IP. Trial 2 was a multisite grazing study performed with heifers and steers to compare ADG after treatment with one 6-pellet, coated implant delivering 21 mg EB and 150 mg TBA (6IP) to sham treated negative controls (SC) over a grazing period of at least 200 d. A completely random design was used at each site, with the goal to treat 70 cattle per site, treatment, and sex; data were pooled across sites. Heifers (n = 558, initial BW = 229 ± 16 kg) and steers (n = 555, initial BW = 235 ± 20 kg) grazed in rotational programs consistent with regional practices for an average of 202 d. When necessary, cattle were supplemented with preserved forage, but no concentrate supplements were fed. Over 202 d, ADG by heifers treated with 6IP was 11.3% greater (P = 0.0035) than SC heifers (0.64 ± 0.06 kg/d), and ADG by steers treated with 6IP was 17.2% greater (P = 0.0054) than SC steers (0.66 ± 0.08 kg/d). In neither study was there evidence that concurrent therapeutic treatments or abnormal health observations were influenced by experimental treatments. These studies demonstrated that a 6-pellet implant with a polymeric, porous coating that delivers 21 mg EB and 150 mg TBA improved ADG by grazing heifers and steers for at least 200 d compared to sham-implanted negative controls.

Topics: Animal Husbandry; Animal Nutritional Physiological Phenomena; Animals; Cattle; Dose-Response Relationship, Drug; Drug Implants; Ear; Estradiol; Female; Herbivory; Male; Polymers; Sex Factors; Time Factors; Treatment Outcome; Trenbolone Acetate; Weight Gain

The potential interaction of growth-promoting implants and genetic markers previously reported to be associated with growth, carcass traits, and tenderness was evaluated. Two implant protocols were applied to subsets of steers (n = 383) and heifers (n = 65) that were also genotyped for 47 SNP reported to be associated with variation in growth, fat thickness, LM area, marbling, or tenderness. The "mild" protocol consisted of a single terminal implant [16 mg estradiol benzoate (EB), 80 mg trenbalone acetate (TBA) or 8 mg EB, 80 mg TBA given to steers and heifers, respectively]. The "aggressive" protocol consisted of both a growing implant (8 mg EB, 40 mg TBA) for the lightest half of the animals on the aggressive protocol and 2 successive implants (28 mg EB, 200 mg TBA) given to all animals assigned to the aggressive treatment. Implant protocol had measurable impact on BW and ADG (P < 0.05), with the aggressive protocol increasing these traits before the terminal implant (relative to the mild protocol), whereas the mild protocol increased ADG after the terminal implant so that the final BW and ADG over the experimental period were similar between protocols. Animals on the aggressive protocol had significantly increased (P < 0.05) LM area (1.9 cm(2)), slice shear force (1.4 kg), and intact desmin (0.05 units), but decreased (P < 0.05) marbling score (49 units) and adjusted fat thickness (0.1 cm), and yield grade (0.15 units). Among both treatments, 8 of 9 growth-related SNP were associated with BW or ADG, and 6 of 17 tenderness-related SNP were associated with slice shear force or intact desmin. Favorable growth alleles generally were associated with increased carcass yield traits but decreased tenderness. Similarly, favorable tenderness genotypes for some markers were associated with decreased BW and ADG. Some interactions of implant protocol and genotype were noted, with some growth SNP alleles increasing the effect of the aggressive protocol. In contrast, putative beneficial effects of favorable tenderness SNP alleles were mitigated by the effects of aggressive implant. These type of antagonisms of management variables and genotypes must be accounted for in marker assisted selection (MAS) programs, and our results suggest that MAS could be used to manage, but likely will not eliminate negative impact of implants on quality.

Topics: Animals; Cattle; Dose-Response Relationship, Drug; Drug Implants; Estradiol; Female; Genetic Markers; Genotype; Male; Meat; Nuchal Cord; Trenbolone Acetate; Weight Gain

Comparative studies of the effects of Nordette and Lutofolone on 15 days old chicken were carried out to determine their effects on growth performance, biochemical parameters and an analysis of hormonal residues in the liver and muscle. Sixty chickens were equally divided into three groups. Group 1 was served as a control. Groups 2 and 3 were treated daily with Nordette (1 mg/kg B.W.) mixed in the ration and Lutofolone (0.5 mg/kg B.W.) orally via a bent stainless steel feeding tube, respectively, for 30 days (from the 15th till the 45th day old). Then these treated groups were left for another 15 days without any treatment. Blood samples were collected at 45 and 60 days old and used for biochemical studies, while liver and muscles were excised from each chicken and used to prepare tissue homogenate for estimation of hormonal residues (estrogen and progesterone). Both drugs caused a gain in body weight. They also increased several serum variables, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), cholesterol, creatine kinase (CK), creatinine and uric acid, and reduced total proteins, albumin and globulin levels at 30 days post-administration. Moreover, this study exhibited a significant increase in the levels of estrogen residues in the liver and muscle. Estrogen level was much higher in the liver than muscles. However, some of these findings were insignificant changed at 15 days post-stopping of the hormones. Data on the biochemical parameters and residue levels obtained from these results clearly indicate that anabolic agents may entail a special risk to the chickens and probably to the consumer.

Topics: Animals; Chickens; Estradiol; Ethinyl Estradiol-Norgestrel Combination; Liver; Muscle, Skeletal; Progesterone; Weight Gain

At each of three locations, 400 steers and an equal number of heifers were randomized to 10 treatment groups. The purpose of the studies was to evaluate the response of feedlot steers and heifers to single implants containing a combination of estradiol benzoate (EB) and trenbolone acetate (TBA) at two different ratios each at three doses. The selected ratios corresponded to 1E2(estradiol-17 beta):5TBA and 1E2:10TBA. The two ratios were each tested at three different EB/TBA doses (1:5 at 20/70, 40/140, and 60 mg/210 mg, 1:10 and 14/100, 28/200, and 42 mg/300 mg). The test groups were compared to those given each of the compounds alone (60 mg of EB or 300 mg of TBA), as well as to groups reimplanted with Synovex S or Synovex H implants and untreated controls. Steers (P < .01) and heifers (P < .05) implanted with the 1:10 E2:TBA implants gained faster and had better feed conversion (FC) than their counterparts given 1:5 E2:TBA over the 140-d trial. The results indicated that both estradiol benzoate and trenbolone acetate contributed to the efficacy of the combination implant. Contour plots of ADG and FC indicate that increasing the amount of EB above approximately 36 and 37 mg does not significantly increase the response of steers. The results of these studies indicate that the 28 EB/200 TBA dose is close to optimal for growth promotion and feed conversion in both heifers and steers. In steers, carcass value was increased (P < .01) in all test groups except the group give TBA only. Despite a slight reduction in marbling score and percentage of Choice carcasses, carcasses of steers treated with either 28 mg of EB/200 mg of TBA or 42 mg of EB/300 mg of TBA were more valuable (P < .05) than carcasses from steers in any of the 1:10 ratio EB/TBA groups. Carcass values for groups reimplanted with Synovex S or Synovex H or implanted with EB alone were not significantly different from those for groups implanted with any dose of the 1:10 EB/TBA ratio.

Topics: Anabolic Agents; Animals; Cattle; Dose-Response Relationship, Drug; Drug Combinations; Drug Implants; Estradiol; Female; Growth Substances; Male; Meat; Time Factors; Trenbolone Acetate; Weight Gain

Undernutrition during development alters the expression of peptides that control energy expenditure and feeding behavior. Estrogens can also modulate these peptides. Here, we analyze whether the early postnatal administration of estradiol modulates the effects of undernutrition on neuroendocrine parameters in adult female Wistar rats.. Control rats were fed a control diet. Undernourished pups were submitted to a restricted diet with half of the undernourished rats receiving 0.4 mg/kg s.c. of estradiol benzoate (EB) from postnatal day (P) 6 until P13. Quantitative real-time polymerase chain reaction was performed to determine expression in the hypothalamus of agouti-related peptide (AgRP), proopiomelanocortin (POMC), neuropeptide Y (NPY), and cocaine- and amphetamine-regulated transcript. Plasma estradiol, testosterone, and adiponectin levels were measured by enzyme-linked immunosorbent assay. Total and acylated ghrelin levels were measured in plasma by radioimmunoassay. Insulin and leptin were measured by mulitplex immunoassays.. Undernourishment decreased body weight, fat mass, plasma leptin and insulin levels, and hypothalamic POMC mRNA levels. An increase in orexigenic signals AgRP and NPY mRNA levels, and in plasma adiponectin levels were found in undernourished animals. Early postnatal treatment with EB to undernourished female rats reversed the effects of undernutrition on adult hypothalamic POMC mRNA levels. In addition, neonatal EB treatment to undernourished females significantly decreased adult plasma testosterone, estradiol, and acylated ghrelin levels.. Our results suggest that increased estradiol during a critical period of development has the capacity to modulate the alterations that undernutrition produces on energy metabolism.

Topics: Animals; Diet, Protein-Restricted; Disease Susceptibility; Estradiol; Estrogens; Female; Fetal Growth Retardation; Gene Expression Regulation, Developmental; Hypothalamus; Injections, Subcutaneous; Lactation; Malnutrition; Maternal Nutritional Physiological Phenomena; Nerve Tissue Proteins; Neurons; Pregnancy; Protein Deficiency; Random Allocation; Rats, Wistar; Weaning; Weight Gain

Short-term abstinence from food intake, planned or unplanned, is unavoidable in modern life, but negatively correlated with appetite control and obesity. This study investigated the role of estradiol in feeding and body weight (BW) reactions to short-span cessation of feeding. During acute 1-6-h re-feeding, 12-h food-deprived (FD), estradiol benzoate (EB)-implanted ovariectomized rats ate less food and gained less weight than FD animals implanted with oil (O). Full fed (FF)- and FD-EB consumed equal amounts of food over 24 h, but weight gain was greater in the latter; 24-h food intake and BW gain in FD-O exceeded FD-EB. Caudal fourth ventricular administration of the AMPK activator AICAR increased dorsal vagal complex AMPK activity in FD-EB and FD-O, but elicited dissimilar adjustments in hypothalamic metabolic neuropeptide transmitter expression, while respectively enhancing or reducing acute re-feeding in these animals and reversing FD-O weight gain. Drug-treated FD-EB and FD-O exhibited respective feeding and weight gain increases between 6-24 h. AICAR enhanced 24-h consumption in FD-EB vs. FF-EB, but cumulative intake and BW gain were greater in AICAR-treated FD-O vs. FD-EB. Results show that estradiol limits acute re-feeding after short-term feeding suspension, but augments acute re-feeding when energy depletion coincides with suspended feeding. This compound metabolic stress exerts steroid-dependent effects during later resumption of circadian-induced feeding, for example, increased consumption vs. weight gain in the presence vs. absence of estradiol. These studies provide novel evidence that estrogen mitigates acute and post-acute adverse effects of disrupted fuel acquisition on energy balance.

Topics: Aminoimidazole Carboxamide; Animals; Behavior, Animal; Body Weight; Estradiol; Estrogens; Feeding Behavior; Female; Food Deprivation; Hypoglycemic Agents; Ovariectomy; Rats; Rats, Sprague-Dawley; Ribonucleotides; Weight Gain

Postmenopausal women are prone to develop obesity and insulin resistance, which might be related to skeletal muscle mitochondrial dysfunction. In a rat model of ovariectomy (OVX), skeletal muscle mitochondrial function was examined at short- and long-term periods after castration. Mitochondrial parameters in the soleus and white gastrocnemius muscle fibers were analyzed. Three weeks after surgery, there were no differences in coupled mitochondrial respiration (ATP synthesis) with pyruvate, malate, and succinate; proton leak respiration; or mitochondrial reactive oxygen species production. However, after 3 wk of OVX, the soleus and white gastrocnemius muscles of the OVX animals showed a lower use of palmitoyl-carnitine and glycerol-phosphate substrates, respectively, and decreased peroxisome proliferator-activated receptor-γ coactivator-1α expression. Estrogen replacement reverted all of these phenotypes. Eight weeks after OVX, ATP synthesis was lower in the soleus and white gastrocnemius muscles of the OVX animals than in the sham-operated and estrogen-treated animals; however, when normalized by citrate synthase activity, these differences disappeared, indicating a lower muscle mitochondria content. No differences were observed in the proton leak parameter. Mitochondrial alterations did not impair the treadmill exercise capacity of the OVX animals. However, blood lactate levels in the OVX animals were higher after the physical test, indicating a compensatory extramitochondrial ATP synthesis system, but this phenotype was reverted by estrogen replacement. These results suggest early mitochondrial dysfunction related to lipid substrate use, which could be associated with the development of the overweight phenotype of ovariectomized animals.

Topics: Adenosine Triphosphate; Adiposity; Animals; Citrate (si)-Synthase; Energy Metabolism; Estradiol; Estrogen Replacement Therapy; Exercise Tolerance; Female; Lipid Metabolism; Mitochondria, Muscle; Mitochondrial Turnover; Muscle Fibers, Skeletal; Ovariectomy; Overweight; Oxygen Consumption; Phenotype; Rats; Rats, Wistar; Time Factors; Weight Gain

The primary objective of this study was to investigate the impact of animal-level factors including energy balance and environmental/management stress, on the ovarian function of Bos indicus heifers treated to synchronize ovulation. Two-year-old Brahman (BN) (n = 30) and BN-cross (n = 34) heifers were randomly allocated to three intravaginal progesterone-releasing device (IPRD) treatment groups: (i) standard-dose IPRD [Cue-Mate(®) (CM) 1.56 g; n = 17]; (ii) half-dose IPRD [0.78 g progesterone (P(4)); CM 0.78 g; n = 15]; (iii) half-dose IPRD + 300 IU equine chorionic gonadotrophin at IPRD removal (CM 0.78 g + G; n = 14); (iv) and a control group, 2× PGF(2α) [500 μg prostaglandin F(2α) (PGF(2α))] on Day -16 and -2 (n = 18). Intravaginal progesterone-releasing device-treated heifers received 250 μg PGF(2α) at IPRD insertion (Day -10) and IPRD removal (Day -2) and 1 mg oestradiol benzoate on Day -10 and -1. Heifers were managed in a small feedlot and fed a defined ration. Ovarian function was evaluated by ultrasonography and plasma P(4) throughout the synchronized and return cycles. Energy balance was evaluated using plasma insulin-like growth factor 1 (IGF-I) and glucose concentrations. The impact of environmental stressors was evaluated using plasma cortisol concentration. Heifers that had normal ovarian function had significantly higher IGF-I concentrations at commencement of the experiment (p = 0.008) and significantly higher plasma glucose concentrations at Day -2 (p = 0.040) and Day 4 (p = 0.043), than heifers with abnormal ovarian function. There was no difference between the mean pre-ovulatory cortisol concentrations of heifers that ovulated or did not ovulate. However, heifers that ovulated had higher cortisol concentrations at Day 4 (p = 0.056) and 6 (p = 0.026) after ovulation than heifers that did not ovulate.

Topics: Administration, Intravaginal; Animals; Blood Glucose; Cattle; Estradiol; Estrus Synchronization; Female; Hydrocortisone; Insulin-Like Growth Factor I; Ovary; Ovulation; Progesterone; Weight Gain

A study was performed to determine if targeted metabolic profiling of cattle sera could be used to establish a predictive tool for identifying hormone misuse in cattle. Metabolites were assayed in heifers (n = 5) treated with nortestosterone decanoate (0.85 mg/kg body weight), untreated heifers (n = 5), steers (n = 5) treated with oestradiol benzoate (0.15 mg/kg body weight) and untreated steers (n = 5). Treatments were administered on days 0, 14, and 28 throughout a 42 day study period. Two support vector machines (SVMs) were trained, respectively, from heifer and steer data to identify hormone-treated animals. Performance of both SVM classifiers were evaluated by sensitivity and specificity of treatment prediction. The SVM trained on steer data achieved 97.33% sensitivity and 93.85% specificity while the one on heifer data achieved 94.67% sensitivity and 87.69% specificity. Solutions of SVM classifiers were further exploited to determine those days when classification accuracy of the SVM was most reliable. For heifers and steers, days 17-35 were determined to be the most selective. In summary, bioinformatics applied to targeted metabolic profiles generated from standard clinical chemistry analyses, has yielded an accurate, inexpensive, high-throughput test for predicting steroid abuse in cattle.

Topics: Anabolic Agents; Animals; Cattle; Creatinine; Estradiol; Female; Male; Nandrolone; Nandrolone Decanoate; Predictive Value of Tests; Sensitivity and Specificity; Substance Abuse Detection; Time Factors; 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

Fall-weaned crossbred steer calves (n = 300; 184 +/- 2.9 kg) received either no implant (Control) or were implanted with Synovex-C (SC = 10 mg estradiol benzoate + 100 mg progesterone), Synovex-S (SS = 20 mg estradiol benzoate + 200 mg progesterone), or Revalor-G (RG = 8 mg estradiol-17beta + 40 mg trenbolone acetate) to determine the effects of implants on weight gain during winter grazing on dormant tallgrass prairie, subsequent grazing and finishing performance, and carcass characteristics. Steers grazed two dormant tallgrass prairie pastures from October 16, 1996, until March 29, 1997 (164 d), and received 1.36 kg/d of a 25% CP supplement that supplied 100 mg of monensin/steer. Following winter grazing, all steers were implanted with Ralgro (36 mg zeranol) and grazed a common tallgrass prairie pasture until July 17 (110 d). After summer grazing, all steers were implanted with Revalor-S (24 mg estradiol-17beta + 120 mg trenbolone acetate), and winter implant treatment groups were equally allotted to four feedlot pens. Steers were harvested November 17, 1997, after a 123-d finishing period. Daily gains during the winter grazing phase averaged .28, .32, .32, or .35 kg/d, respectively, for Control, SC, SS, or RG steers and were greater (P < .01) for implanted steers than for Controls. Summer daily gains were similar (1.05 +/- .016 kg/d; P > or = .61) for all treatment groups. Feedlot daily gains were also similar (1.67 +/- .034 kg/d; P > or = .21), with implanted steers weighing 14 kg more than Control steers (P = .05) at harvest, despite similar management during summer grazing and feedlot phases. Control steers tended (P = .06) to have lower yield grades. There were no differences (P = .99) in marbling between implanted and nonimplanted steers. Steers implanted during the wintering phase had increased skeletal and overall (P < .01) carcass maturities compared with nonimplanted steers, which resulted in more "B" and "C" maturity carcasses. Because carcass maturity score affects quality grade, the increased maturities of implanted steers resulted in a $9.04 decrease in carcass value/100 kg (P < .01) compared with Controls. The results of this study indicate that growth-promoting implants are efficacious for cattle wintered on dormant native range despite low daily gains. This increased weight is maintained through the summer grazing and feedlot phases; however, the benefit of the increased weight may be offset by decreased carcass quality grade and value

Topics: Anabolic Agents; Animal Feed; Animal Husbandry; Animals; Body Composition; Cattle; Drug Combinations; Energy Metabolism; Estradiol; Male; Progesterone; Seasons; Trenbolone Acetate; Weight Gain

In order to understand the mechanism of increasing body fat in perimenopausal and postmenopausal women, an ovariectomy-induced obesity model was used to study the role of leptin. In this investigation, a long-term study lasted for 13 weeks was conducted to monitoring the change of serum leptin level in rats after the loss of estrogen, and also to examine the influence of estrogen replacement. The results showed that three weeks after the removal of ovaries the body weight of Ovx rats was already significantly higher than the other two groups, and continued to gain more weight thereafter. Accompanying with the significant weight gain was the changes in the serum leptin levels. The leptin concentration declined gradually during the first half of experimental period, dropping down to an almost undetectable level at week 7 (0.216+/-0.132 ng/ml). Subsequently, its concentration began to elevate, and by the end of experiment leptin level was significantly higher (3.182+/-0.936 ng/ml) than the value before the operation (0.818+/-0.242 ng/ml). This fluctuation of serum leptin level caused by ovariectomy was eliminated by the replacement of estrogen. The present data indicate that ovariectomy-induced weight gain is caused by the early drop in leptin level. The later rise in leptin production is connected to the increased body weight probably originated from a reduced sensitivity in leptin signal.

Topics: Animals; Disease Models, Animal; Estradiol; Female; Humans; Leptin; Menopause; Obesity; Ovariectomy; Ovary; Proteins; Rats; Rats, Sprague-Dawley; Weight Gain

Sixty nonpregnant, mature beef cows were used to evaluate the influence of steroid implants on performance and carcass composition of beef cows fed a high-concentrate diet. Twelve nonfed cows were slaughtered at 0 d. Remaining cows were stratified by weight and randomly assigned to an implant treatment and feeding period (28 or 56 d). Treatments included 1) no implant (control), 2) a 200-mg trenbolone acetate (TBA) implant, 3) a 200-mg testosterone propionate +20 mg of estradiol benzoate (TEB) implant, or 4) both implants (TBA + TEB). As days on feed increased, hot carcass weight (HCW), carcass soft tissue (CST) weight, adjusted fat thickness (AFT), longissimus muscle area (LMA), percentage of CST, and percentage of CST lipid increased (P < .05) and percentage of CST crude protein and moisture decreased (P < .05). Cows fed for 56 d accumulated (P < .05) more kilograms of lean than cows fed for 28 d, and cows fed for 28 d tended (P = .08) to have more kilograms of lean than nonfed cows. Cows fed for 56 d had (P < .05) higher dressing percentages than nonfed cows or cows fed for 28 d, and nonfed cows had (P < .05) higher dressing percentages than cows fed for 28 d. Implanted cows compared with control cows had (P < .05) heavier final weights, increased gains, improved feed efficiency, heavier hot carcass weights, larger LMA, higher cutability yield grades, compositionally leaner CST (higher percentage of moisture and protein and lower percentage of lipid), and more kilograms of lean. In addition, double-implanted (TBA + TEB) cows had (P < .05) more kilograms of CST than control and TBA-implanted cows. Furthermore, cows implanted with TBA had (P < .05) lower dressing percentages than TEB-implanted cows, less AFT than controls, and fewer kilograms of lipid than cows on the other three treatments. Full feeding of thin beef cows for 28 or 56 d increased carcass weight through an increase in CST lean as well as fat (lipid). The live performance and accretion of lean during realimentation can be enhanced by using anabolic implants.

Topics: Animals; Body Composition; Cattle; Drug Implants; Eating; Estradiol; Female; Random Allocation; Steroids; Testosterone; Trenbolone Acetate; Weight Gain

Topics: Animals; Estradiol; Estrogens; Female; Gonadotropins, Equine; Hypertension; Kidney; Nephrectomy; Rats; Serotonin; Weight Gain