Growth and carcass characteristics of pasture fed LHRH immunocastrated, castrated and intact Bos indicus bulls

Productive performance and carcass characteristics of castrated and non-castrated Beefalo-Nellore beef cattle finished in a feedlot or kept on pasture

Beefalo is a fertile hybrid descendant of domestic cattle (Bos taurus) and American buffalo (Bison bison). Crossbred (¾Beefalo¼Nellore) beef cattle raised and finished in a feedlot or on pasture were evaluated for the effect of two ages (8 and 13 months) at castration on nutrient intake, performance, and carcass characteristics. In the feedlot, they received a total diet with a roughage:concentrate ratio of 55:45, and those kept on Brachiaria decumbens pastures were supplemented at 0.8% of body weight (BW) with the same concentrate based on corn and soybean meal (17.8% CP and 73% TDN). Thirty-six crossbred (¾ Beefalo ¼ Nellore) beef cattle with 209.2 ± 14.6 kg BW were used, which at weaning, at 8 months of age, were randomly divided into two groups, one of them destined to the feedlot system and the other group to the supplementation system on pasture. In each system (feedlot and pasture) the following treatments were distributed: castration at 8 months (at weaning, C8), castration at 13 months (C13), and non-castrated (NC), with six animals per treatment by system. All animals were slaughtered at 18 months of age. There was no significant interaction between the systems and castration ages for all variables studied. The averages of slaughter weight of feedlot animals were 475.6; 494.3 and 510.7 kg; and finished in pasture were 424.3; 428.0 and 418.7 kg for C8, C13, and NC treatments, respectively. The average subcutaneous fat thickness of the feedlot steers were 4.5, 3.5, and 1.3 mm, and for pasture-finished steers were 2.4, 1.6, and 1.8 mm for C8, C13, and NC treatments, respectively. Non-castrated animals have greater performance and carcass characteristics than castrated animals independent of the finished system. Animals non-castrated finished on Brachiaria grass pastures and slaughtered at 18 months of age require more intensive feeding management or even greater age at slaughter to obtain an ideal carcass finishing despite castration.

Fetal Programming and Its Effects on Meat Quality of Nellore Bulls

This work aimed to evaluate the effects of prenatal nutritional stimulation at different pregnancy stages on carcass traits and meat quality in bovine progeny. For this purpose, 63 Nellore bulls, born from cows submitted to three nutritional plans, were used: not programmed (NP), which did not receive protein supplementation; partially programmed (PP), which had protein-energy supplementation (0.3% of mean body weight of each batch) only in the final third of pregnancy; and full programming (FP), which received supplementation (0.3% of mean body weight of each batch) throughout pregnancy. The averages of parameters were submitted to the ANOVA, and the supplementation periods, which were different when p value < 0.05, were compared. Carcass weights and rib eye area (REA) did not differ between treatments (p > 0.05), but subcutaneous fat thickness (SFT) showed a tendency (p = 0.08) between groups. For lipids and marbling, no differences were found (p > 0.05). In the analyses of maturation time and shelf life, no difference was observed between treatments. However, there was a tendency between treatments at 14 days of maturation time for cooking loss (CL) (p = 0.08). Treatments did not affect shear force in the progenies (p > 0.05). Fetal programming had no effect on the meat quality of Nellore bulls.

Effects of Sex Class, a Combined Androgen and Estrogen Implant, and Pasture Supplementation on Growth and Carcass Performance and Meat Quality of Zebu-Type Grass-Fed Cattle

Forty-seven Zebu calves were used to determine the effects of class (bull or steer), supplementation (SUPPL, a poultry litter-based supplement or mineral supplementation), and implant (20 mg estradiol combined with 120 mg of trenbolone acetate or no implant) on growth and carcass performance and beef eating quality. The average daily gain (ADG) of implanted cattle significantly increased for steers, but not for bulls. The SUPPL treatment increased ADG by 8.63% from day 0 to end, and shortened in 73.3 d the time to reach 480 kg BW (p < 0.01). Compared to bulls, the steer carcasses exhibited more desirable maturity and finish scores, thicker back fat (p < 0.05), and yielded greater (p < 0.01) percentages of high-value boneless subprimals (HVBLS) (+1.64%) and total cuts (1.35%). The SUPPL bulls dressed 2.63 and 1.63% greater than non-supplemented bulls and SUPPL steers, respectively (p < 0.05). Meat sensory quality was subtly affected (p < 0.05) by sex class or supplementation. The implant did not affect (p > 0.05) shear force or sensory ratings. The supplementation improved key growth performance traits while it adversely affected tenderness-related sensory traits. The implant enhanced the rate of gain of steers only, without improving cut-out yields or inducing adverse effects on palatability traits in both steers and bulls.

Economic values of reproductive, growth, feed efficiency and carcass traits in Nellore cattle

A bioeconomic model was developed to calculate the economic value (ev) of reproductive and growth performance, feed efficiency and carcass traits of a seedstock Nellore herd. Data from a full-cycle cattle operation (1,436 dams) located in the Brazilian Cerrado were assessed. The ev was calculated by the difference in profit before and after one-unit improvement in the trait, with others remaining unchanged. The ev was standardized by the phenotypic standard deviation of each trait. Preweaning average daily gain (ADG) was the most economically important trait evaluated (R$ 58.04/animal/year), followed by age at first calving (R$ 44.35), postweaning ADG (R$ 31.43), weight at 450 days (R$ 25.36), accumulated productivity (R$ 21.43), ribeye area (R$ 21.35), calving interval (R$ 19.97), feed efficiency (R$ 15.24), carcass dressing per cent (R$ 8.27), weight at 120 days (R$ 6.22), weight at 365 days (R$ 6.06), weight at weaning (210 days, R$ 5.82), stayability (R$ 5.70) and the probability of early calving (R$ 0.32). The effects of all traits on profits are evidence that their selection may result in the economic and genetic progress of the herd if there is genetic variability.

Effectiveness of a New Recombinant antiGnRH Vaccine for Immunocastration in Bulls

Simple Summary

Castration of males is a common procedure in cattle production. Surgical procedures are most commonly used, but there is an increasing interest in non-invasive alternatives to avoid risk of infection, bleeding, pain, stress and to improve animal welfare. Immunization against gonadotropin-releasing hormone is currently being used in livestock, but there is only one commercially available vaccine for cattle and results regarding the number of doses needed to maintain castration are variable. The efficacy, safety, and production parameters of a new antigen for immunocastration in bulls was assessed. Results showed that two doses of the vaccine to 40 10-month-old bulls achieved testosterone suppression below productive performance. Live weight at slaughter and carcass yield was greater in immunized animals than in surgically castrated cattle. Castration effects of the vaccine were maintained until the end of the trial at 24 weeks.

Abstract

Castration by surgical techniques is common in livestock; however, post-surgery complications and concerns for animal wellbeing have created a need for new non-invasive alternatives. The objective of this study was to evaluate immunocastration in bulls using antigen GnRX G/Q; a recombinant peptide proved to be effective in laboratory and companion animals. A nine-month trial with 80 9-month-old Normand x Hereford bulls, kept in a pastured system, was conducted. The herd was divided in half with 40 bulls surgically castrated (SC) and 40 castrated by immunization against GnRH (IC). The antigen was injected on days 0 and 40 of the experiment. After the second dose, the IC group had elevated GnRH antibodies and decreased testosterone levels (below 5 ng/mL) that were maintained for 23 weeks. At slaughter on day 190, the immunocastrated group obtained a higher weight, hot carcass, and dressing percentage than the SC group. There was no difference in pH, color of meat, fat coverage, cooking loss, or tenderness between groups. The bulls showed no inflammatory reaction at the injection site or adverse side effects from the vaccine. Our results demonstrate that immunocastration with GnRX G/Q is an efficient and safe alternative to surgical castration in livestock. Additional work evaluating antigen effects over a longer period is needed to validate commercial viability.

Transcriptome profiling of longissimus lumborum in Holstein bulls and steers with different beef qualities

Previous research regarding Holstein cows has mainly focused on increasing milk yield. However, in order to maximize the economical profits of Holstein cattle farming, it is necessary to fully take advantage of Holstein bulls to produce high-grade beef. The present study aims to investigate different transcriptomic profiling of Holstein bulls and steers, via high-throughput RNA-sequencing (RNA-seq). The growth and beef quality traits of Holstein steers and bulls were characterized via assessment of weight, rib eye area, marbling score, shear force and intramuscular fat percentage of the longissimus lumborum (LL) muscle. The results indicated that castration improved the meat quality, yet reduced the meat yield. Subsequently, RNA-seq of the LL muscle from Holstein steers and bulls revealed a total of 56 differentially expressed genes (DEGs). We performed the functional enrichment analysis in Gene Ontology (GO) annotations of the DEGs using GOseq R package software and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis using KOBAS tool. Through the integrated analysis of DEGs with reported QTLs and SNPs, seven promising candidate genes potentially affecting the beef quality of LL muscle following castration were discovered, including muscle structural protein coding genes (MYH1, MYH4, MYH10) and functional protein coding genes (GADL1, CYP2R1, EEPD1, SHISA3). Among them, MYH10, GADL1, CYP2R1, EEPD1 and SHISA3 were novel candidate genes associated with beef quality traits. Notably, EEPD1 was associated with both meat quality and reproduction traits, thus indicating its overlapping role in responding to hormone change, and subsequently inducing beef quality improvement. Our findings provide a complete dataset of gene expression profile of LL in Holstein bulls and steers, and will aid in understanding how castration influence meat yield and quality.

Ante-and post-mortem strategies to improve the meat quality of high-value muscles harvested from farmed male common eland (Taurotragus oryx)

The effects of immunocastration, pelvic suspension and wet ageing on the meat quality of the longissimus lumborum et thoracis (LTL) and biceps femoris (BF) muscles of male common eland were evaluated. Ten subadult males were either immunocastrated (n = 5) or remained intact (n = 5) throughout a four-month growth trial, after which their carcass sides were randomly allocated to either pelvic- or Achilles-suspension. The LTL and BF were further aged for 14 days, measuring changes in the physical quality weekly. The sensory quality of the LTL and BF were determined after ageing (8/9 days, respectively). Immunocastration had minimal effects on the meat quality of male eland, but pelvic suspension decreased the shear force. All muscles reached minimum shear force after seven days of ageing, and the panellists ranked the pelvic-suspended muscles higher for tenderness traits. Incorporating pelvic suspension and wet ageing into the commercial processing of eland carcasses should be considered to improve overall meat quality.

Effect of Kisspeptin-54 immunization on performance, carcass characteristics, meat quality and safety of Yiling goats

This study aimed to evaluate the effects of kisspeptin-54 immunocastration vaccine on performance, carcass characteristics, meat quality, and safety of Yiling goats. Thirty buck goats were randomly assigned into three groups: PVAX-B2L-Kisspeptin-54-asd immunized (PBK-asd), control, and surgically castrated. PBK-asd immunization significantly stimulated serum anti-kisspeptin antibody production and reduced testosterone hormone compared with the control group (p < .05). Interestingly, PBK-asd plasmid did not integrate into the host genome and had no significant effect on growth hormone, body weight, and average daily gain (ADG). Conversely, surgical castration significantly reduced ADG and carcass weight compared to the control group. Furthermore, PBK-asd immunization did not affect carcass characteristics (dressing percentage, loin area, and fat thickness) and meat quality traits (pH, color, cooking loss, drip loss, and shearing force). These results indicate that the Kisspeptin-54 DNA vaccine is safe and has potential to be used as an alternative to surgical castration for goats without negatively affecting carcass and meat quality.

Yeast culture in the diet of feedlot steers: performance, carcass traits and feeding behavior

ABSTRACT This study aimed to evaluate the performance, apparent digestibility of diet, ingestive behavior which occurred in two moments, carcass traits, being evaluated constituent and non-carcass components, and also the effect the yeast culture could promote in the peripheral temperature of rumen, hull and body temperature. The diets consisted of a constant ratio of 50% forage (maize silage) and 50% concentrate. Thirty-six steers, ½ Angus Nelore, with average age of 11 months and average initial body weight of 339.5±10kg were used in the experiment. The inclusion of yeast culture promoted a higher daily dry matter intake (8.83 vs 9.35kg day-1) and, consequently, a better daily weight gain (1,143 vs. 1,325kg day-1) in the initial feedlot phase, with no difference in other periods. The apparent digestibility of the diet containing yeast culture was higher than the control diet (69.69 versus 68.32%, respectively), and its use did not interfere with the feeding behavior of the animals. Based on our findings, supplementation with yeast culture may bring positive results in the initial feedlot phase.

Replacement of a protein–energy supplement by a same-cost maize-based supplement on performance and product quality of pasture-finished Nellore heifers

Context In the largest beef-producing countries in the world, the slaughter of female cows accounts for ~30–40% of all beef produced. Aims The objective of this study was to evaluate the replacement of a protein–energy supplement (PES) by a same-cost maize-based supplement (MBS) on the performance and final product of Nellore heifers grazing Brachiaria brizantha cv. Marandu pasture during the wet season in Brazil. Methods Ninety-six Nellore heifers of bodyweight (BW) 281 ± 7.55 kg and aged 23 months were used. Six were slaughtered at the start of the experiment. The remaining 90 heifers received one of the following three supplements with their predominantly pasture diet for 133 days: control, mineral salt ad libitum; PES, with protein 250 g/kg dry matter (DM) and total digestible nutrient 600 g/kg DM, offered at 3 g/kg BW.day (as-fed basis); MBS, with crude protein 90 g/kg DM and total digestible nutrient 850 g/kg DM, offered at 7 g/kg BW.day (as-fed basis). The variables were evaluated in a completely randomised block design with 30 heifers per treatment. Key results Average daily gain and final BW were similar (P &gt; 0.05) in PES and MBS treatments, and relative to the control increased (P &lt; 0.01) average daily gain by ~24% and final BW by 7%. Pasture intakes were decreased, with substitution levels of 8.0% for heifers receiving PES and 10.4% for those receiving MBS. Carcass weight (kg/day) and carcass gain (g carcass/kg BW) were greater (P &lt; 0.001) for heifers receiving MBS and PES than for the control group. Backfat depth was greater (P &lt; 0.001) in heifers receiving MBS (7.91 mm) than in those receiving PES (6.25 mm), and the lowest (P &lt; 0.001) measurement was observed in the control group (4.85 mm). Conclusions Maize-based supplement (7 g/kg BW.day) provided the same growth rate as PES (3 g/kg BW.day) but yielded heavier and slightly fatter carcasses of pasture-finished Nellore heifers during the wet season (133 days) with a similar cost, and with more total digestible nutrients than pasture plus mineral salt. Implications Maize-based supplement provided to Nellore heifers on pasture may improve performance despite lower pasture intakes but needs to be evaluated carefully in terms of costs involved.

Effects of immunocastration performed at two live weights on the growth physiology, temperament and testicular development of feral beef bulls

The aim of this study was to examine the effect of administering an anti-gonadotropin-releasing hormone vaccine (Improvac^® , developed for pigs) on the performance, temperament, testicular development, and hormone and metabolite profiles of feral bulls (Bos taurus) vaccinated at two different live weights (LW). In all, 16 Serrana de Teruel animals were involved in this 2 x 2 factorial design using the factors LW (LIGHT vs. HEAVY) and vaccine treatment (control, C vs. vaccinated, VA). All animals received the same diet (ad libitum concentrate plus straw) over a 164-day fattening period. Temperament was assessed using chute and flight speed tests. Testicular diameter and subcutaneous fat thickness were recorded. Testosterone, IGF-1, urea, NEFA, and creatinine profiles were analyzed. Bull weight gain was reduced in VA compared to C animals, regardless of the initial LW. The vaccine did not affect the temperament tests, subcutaneous fat thickness or NEFA and creatinine concentrations and had minor effects on linear body measures. The vaccine inhibited testicular growth, reduced plasma testosterone to residual levels, and increased urea concentrations. LIGHT-C animals exhibited increased mean plasma IGF-1 concentrations compared to LIGHT-VA animals. In conclusion, vaccination reduced bull growth and sexual development irrespective of LW at immunization.

Prediction of hub genes associated with intramuscular fat content in Nelore cattle

BACKGROUND

The aim of this study was to use transcriptome RNA-Seq data from longissimus thoracis muscle of uncastrated Nelore males to identify hub genes based on co-expression network obtained from differentially expressed genes (DEGs) associated with intramuscular fat content.

RESULTS

A total of 30 transcriptomics datasets (RNA-Seq) obtained from longissimus thoracis muscle were selected based on the phenotypic value of divergent intramuscular fat content: 15 with the highest intramuscular fat content (HIF) and 15 with the lowest intramuscular fat content (LIF). The transcriptomics datasets were aligned with a reference genome and 65 differentially expressed genes (DEGs) were identified, including 21 upregulated and 44 downregulated genes in HIF animals. The normalized count data from DEGs was then used for co-expression network construction. From the co-expression network, four modules were identified. The topological properties of the network were analyzed; those genes engaging in the most interactions (maximal clique centrality method) with other DEGs were predicted to be hub genes (PDE4D, KLHL30 and IL1RAP), which consequently may play a role in cellular and/or systemic lipid biology in Nelore cattle. Top modules screened from the gene co-expression network were identify. The two candidate modules had clear associated biological pathways related to fat development, cell adhesion, and muscle differentiation, immune system, among others. The hub genes belonged in top modules and were downregulated in HIF animals. PDE4D and IL1RAP have known effects on lipid metabolism and the immune system through the regulation of cAMP signaling. Given that cAMP is known to play a role in lipid systems, PDE4D and IL1RAP downregulation may contribute to increased levels of intracellular cAMP and thus may have effects on IF content differences in Nelore cattle. KLHL30 may have effects on muscle metabolism. Klhl protein families play a role in protein degradation. However, the downregulation of this gene and its role in lipid metabolism has not yet been clarified.

CONCLUSIONS

The results reported in this study indicate candidate genes and molecular mechanisms involved in IF content difference in Nelore cattle.

Effects of immunocastration on the performance and meat quality traits of feedlot-finished Bos indicus (Nellore) cattle

This study aimed to evaluate the effects of immunocastration on the performance, testosterone concentration, carcass traits and meat quality of feedlot-finished Nellore cattle. Fifty-eight males (430 ± 36 kg bodyweight; 24 months old) were separated into three groups in a randomised complete design: surgically castration (n = 15), immunocastrated (anti-gonadotropin-releasing hormone (Bopriva®) vaccine, n = 21) and non-castrated (n = 22). The animals were housed in individual pens and fed ad libitum for 90 days with a common diet comprising 70% concentrate and 30% roughage (corn silage). The non-castrated animals had a greater average daily gain, feed efficiency, hot carcass weight and carcass yield than the surgically castrated and immunocastrated animals (P &lt; 0.05). Surgically castrated cattle grew faster and more efficiently than those castrated immunologically (P &lt; 0.05). The surgically castrated and immunocastrated animals had higher colour values L*, a* and b* and cooking loss than non-castrated animals (P &lt; 0.05). In conclusion, immunocastration decreased cattle performance compared with surgically castrated or non-castrated animals. However, immunocastration resulted in better meat quality compared with non-castrated, making it an alternative to surgical castration with no negative effects on animal welfare.

Influence of extending the pre-slaughter interval after second vaccination on the carcass cutting yield and the quality of meat from immunocastrated lambs

The influence of extending the vaccination-to-slaughter interval of immunocastrated lambs on carcass cutting yield and meat quality of the Longissimus thoracis (LT) muscle was investigated in forty Dohne Merino lambs (8.5 months old; 53.7 ± 4.8 kg). Immunocastration booster vaccination intervals of six (IC6; n = 10) and four (IC4; n = 10) weeks prior to the slaughter age were used, with two weeks between primary and secondary vaccinations. A further 10 lambs were Burdizzo-castrated at 6.5 months old (B). The control treatment remained intact (R; n = 10). Prime cutting yields, LT muscle area, LT subcutaneous fat thickness and instrumental meat quality were accessed. Both castration methods increased LT fat thickness and decreased meat CIE a* (redness) values. Extending the vaccination-to-slaughter interval of immunocastrates increased the gastrointestinal tract fat and decreased meat redness. Immunocastration of male lambs can thus be used to manipulate backfat without negatively influencing carcass weight, cutting yield or meat quality.

Hepatic transcriptional changes in critical genes for gluconeogenesis following castration of bulls

Objective

This study was performed to understand transcriptional changes in the genes involved in gluconeogenesis and glycolysis pathways following castration of bulls.

Methods

Twenty Korean bulls were weaned at average 3 months of age, and castrated at 6 months. Liver tissues were collected from bulls (n = 10) and steers (n = 10) of Korean cattle, and hepatic gene expression levels were measured using quantitative real-time polymerase chain reaction. We examined hepatic transcription levels of genes encoding enzymes for irreversible reactions in both gluconeogenesis and glycolysis as well as genes encoding enzymes for the utilization of several glucogenic substrates. Correlations between hepatic gene expression and carcass characteristics were performed to understand their associations.

Results

Castration increased the mRNA (3.6 fold; p<0.01) and protein levels (1.4 fold; p< 0.05) of pyruvate carboxylase and mitochondrial phosphoenolpyruvate carboxykinase genes (1.7 fold; p<0.05). Hepatic mRNA levels of genes encoding the glycolysis enzymes were not changed by castration. Castration increased mRNA levels of both lactate dehydrogenase A (1.5 fold; p<0.05) and lactate dehydrogenase B (2.2 fold; p<0.01) genes for lactate utilization. Castration increased mRNA levels of glycerol kinase (2.7 fold; p<0.05) and glycerol-3-phosphate dehydrogenase 1 (1.5 fold; p<0.05) genes for glycerol utilization. Castration also increased mRNA levels of propionyl-CoA carboxylase beta (mitochondrial) (3.5 fold; p<0.01) and acyl-CoA synthetase short chain family member 3 (1.3 fold; p = 0.06) genes for propionate incorporation.

Conclusion

Castration increases transcription levels of critical genes coding for enzymes involved in irreversible gluconeogenesis reactions from pyruvate to glucose and enzymes responsible for incorporation of glucogenic substrates including lactate, glycerol, and propionate. Hepatic gluconeogenic gene expression levels were associated with intramuscular fat deposition.

Castration methods in crossbred cattle raised on tropical pasture

The aim of this study was to evaluate the effects of castration methods (surgical or immunological – GnRH vaccine) on performance and carcass traits of beef cattle raised until slaughter on tropical pasture. On Day 0, 30 crossbred beef bulls (50% Aberdeen Angus × 50% Nellore) with a bodyweight (BW) of 233 ± 38 kg and age of 8 months were randomly divided into three groups: intact males (INT) – Control, surgically castrated (SUC; Day 1), and immunocastrated (IMC; Days 1, 84 and 237). Serum testosterone concentrations, scrotal circumference, average daily gain, and ultrasonic backfat depth were evaluated at 42-day intervals (eight evaluations). All animals were slaughtered for the evaluation of carcass traits on Day 336. The GnRH vaccine was efficient in suppressing serum testosterone concentrations (P = 0.02) and scrotal circumference (P < 0.01). No difference in performance was observed between IMC and SUC animals, in which average daily gain was reduced by 14% (P < 0.01) and final BW by 7% (P < 0.01) compared with the INT group. Regardless of the method used, castration improved carcass traits by reducing carcass drip loss during cooling (P = 0.02), by increasing hindquarter percentage (P < 0.01), and by tending to increase the proportion of noble cuts (P = 0.05) compared with the INT group. However, the surgical method was more efficient than the other treatments by increasing fat deposition in the carcass (P < 0.01). Anti-GnRH immunisation in beef cattle raised on tropical pasture can replace surgical castration, but both methods reduce performance. However, in this production system, castration could be an efficient method to add value to the carcass by increasing the hindquarter proportion and fat deposition.

Effects of immunocastration and β-adrenergic agonists on the performance and carcass traits of feedlot finished Nellore cattle

β-Adrenergic agonists (β-AA) are non-hormonal growth promoters which promote muscle hypertrophy in supplemented animals. The effects of two β-AA in combination with the immunocastration technique on the performance and carcass traits were evaluated using 96 feedlot Nellore males in a randomized complete block design with two sex conditions (immunocastrated (IC) v. non-castrated (NC)) and three treatments: CON (no β-agonists added), RH (300 mg of ractopamine hydrochloride/day, for 33 days) or ZH (80 mg of zilpaterol·hydrochloride animal/day for 30 days, removed 3 days for required withdrawal period). The trial was carried for 100 days where in the first 70 days animals did not receive β-AA (phase 1) and during the last 30 days they were treated with β-AA (phase 2). The performance and ultrasound measurements of longissimus muscle area (LMA), backfat thickness (BFT) and rump fat thickness (RFT) were evaluated in both phases. No sex condition v. treatment interactions were observed for any trait. The NC animals had higher average daily gain (ADG) and final BW than the IC animals, but they did not differ in dry matter intake (DMI) and feed efficiency (gain to feed). The NC animals showed greater LMA (P=0.0001) and hot carcass weight (P=0.0006), and smaller BFT (P=0.0007), RFT (P=0.0039) and percentage of kidney, pelvic and heart fat (P<0.0001) when compared with IC animals. The animals fed ZH showed greater ADG (P=0.0002), G : F (P<0.0001) and dressing per cent (P=0.0136) than those fed RH and CON diets. No differences in BW and DMI were observed. A interaction between treatment and time on feed was observed for LMA and BFT, in which the animals fed ZH diet showed greater LMA (P<0.01) and lower BFT (P<0.01) at 100 days than the animals fed RH and CON diets, whereas RH and CON diets did not differ. Immunocastration decreases muscle development and increases carcass finishing. In contrast, β-AA increases muscle and decreases fat deposition. The ZH has a higher action on the muscle metabolism than animals fed RH diet. However, RH diet achieves a better balance because it has an intermediary performance between non-supplemented and ZH animals and does not decrease the carcass fat.

Effect of immunocastration with Bopriva on carcass characteristics and meat quality of feedlot Holstein bulls

To evaluate the effect of immunocastration on carcass and meat characteristics, Holstein bulls aged between 7 and 8months with a live weight of 232±1.19kg were given two separate treatments, placebo (intact bulls) versus Bopriva, and then slaughtered after approximately 239days of fattening. While the testosterone levels in intact bulls remained at 0.42ng/ml throughout the study, by day 181, differences (P<0.05) were observed in immunized bulls, with values of 0.21ng/ml. The carcasses of animals treated with Bopriva recorded both a higher hot carcass weight (HCW) and a cold carcass weight (CCW), as well as higher dorsal fat density, marbling and KPH (P<0.05); however, no differences (P>0.05) were observed in the Longissimus lumborum area. No significant differences (P>0.05) were recorded between the treatments for pH, L*, a*, b* C* and H*. The carcasses of the animals treated with Bopriva were heavier, with higher dorsal fat density and marbling score.

Effect of anti-gonadotropin-releasing factor vaccine and band castration on indicators of welfare in beef cattle

Angus crossbred bulls (n = 60; 257 ± 5.4 d of age; initial BW 358.8 ± 3.78 kg) were used to study the effect of a vaccine against gonadotropin-releasing factor (GnRF) and band castration on behavioral and physiological indicators of pain. Cattle were randomly assigned to 1 of 3 treatments: bulls, band-castrated calves without pain mitigation (castrated), and immune-vaccinated animals administered an anti-GnRF vaccine (vaccinated). All animals were fitted with a radio frequency ear tag so that individual animal feed intake and feeding behavior were recorded daily over the entire trial using an electronic feed bunk monitoring system. Two doses of anti-GnRF vaccine were administrated on d -35 and 0 and band castration was performed on d 0. Animal BW was recorded weekly starting on d -36 until d 56. Visual analog scores (VAS) were measured on d -36 -35, -1, and 0, and salivary cortisol concentration was measured at -30, 0, 30, 60, 120, and 270 min on d -35 and 0 after castration. Saliva and blood were obtained on d 1, 2, 5, and 7 and weekly until d 56 for determination of cortisol and complete blood cell count. Video data were collected for pain, sexual, and aggressive behavior daily the first week and once a week until d 56. Data were analyzed with a mixed-effect model with castration, time, and their interactions as main effects. Vaccinated calves had reduced ADG and intake (P < 0.05 and P < 0.001, respectively) during the first week after vaccination. Band-castrated calves had reduced ADG and intake (P < 0.001) until the end of the study. No differences in salivary cortisol and VAS were observed among groups at d -35 after the first vaccination and before band castration. However, on d 0, castrated cattle had greater cortisol concentrations and VAS (P < 0.05 and P < 0.01, respectively) than bulls and vaccinated animals. Complete blood cell count did not differ (P > 0.05) between treatments on d 0, 1, and 2. At d 56, vaccinated calves had greater (P < 0.05) final BW than band-castrated calves and both had less final BW than bulls. There was no indication that vaccination caused any physiological or behavioral changes indicative of pain. In contrast, band castration resulted in elevated cortisol scores and VAS indicative of a pain response and behavior related to pain (P < 0.001) until d 42 of the study. The present study demonstrates that anti-GnRF vaccine is a viable animal welfare-friendly alternative to traditional band castration in beef cattle under North American feedlot practices.

Características de carcaça e da carne de bovinos mestiços não-castrados ou submetidos a diferentes métodos de castração

Objetivou-se com este estudo analisar os efeitos de diferentes métodos de castração de machos mestiços de raças de origem leiteira, sobre as características de carcaça e da carne, em comparação com animais não-castrados. Foram utilizados 84 machos, com idade média de dez meses, distribuídos em quatro grupos de 21 animais: castrados com o uso de burdizzo, por meio de incisão lateral na bolsa escrotal, por remoção do tampão (ápice da bolsa escrotal) ou não-castrados. O abate dos animais ocorreu em frigorífico comercial, aos 30 meses de idade. Animais não-castrados apresentaram maior peso de carcaça fria (208,0±6,2 kg) do que os castrados por diferentes métodos (média 192,0±6,4 kg). Não houve diferença para a espessura de gordura entre os grupos experimentais, mas quando a medida foi ajustada ao peso de carcaça, observou-se maior cobertura de gordura nos animais castrados com burdizzo (0,79±0,08 mm/100 kg) ou por incisão lateral (0,86±0,09 mm/100 kg) do que os não-castrados (0,61±0,05 mm/100 kg). A área de olho de lombo foi maior nos machos não-castrados (60,47±1,94 cm²) do que os castrados com burdizzo (50,41±3,18 cm²). Não houve diferença para as relações músculo/osso e músculo+gordura/osso entre os grupos, mas a relação músculo/gordura foi maior nos animais não-castrados em relação aos castrados pela remoção do tampão e estes superiores aos castrados por incisão lateral. Não houve diferença entre as características sensoriais da carne, mas o grau de marmoreio foi maior nos animais castrados com burdizzo (2,33±0,20 pontos) ou castrados pela remoção do tampão (2,39±0,20 pontos) do que os bovinos não-castrados (1,77±0,12 pontos). O método de castração em bovinos mestiços de origem leiteira abatidos com peso reduzido não promove alterações na qualidade da carcaça e da carne dos animais, mas animais não-castrados apresentam maiores peso de abate e peso de carcaça fria, alem de maior porcentagem de músculo na carcaça e melhor relação músculo/gordura do que os castrados.

Animal welfare and meat quality: the perspective of Uruguay, a "small" exporter country

Public sensitivity towards animal welfare has risen in recent years. Uruguay is a primary meat exporter. Therefore, it is compulsory not only to provide good quality and safe meat, but also to project a welfare friendly image. Uruguayan meat production systems are mainly based on rangeland pastures but, due to international meat prices and the opening of new markets, intensive fattening systems increased. These systems include a wide range of feeding alternatives between pasture and concentrate utilization, involving differences in terms of animal welfare, carcass and meat quality, that require to be studied. Accordingly, some husbandry practices associated mainly with extensive systems must be evaluated, as well as their applicability to international recommendations related to pre-slaughter handling which may not be suitable for local conditions. In the present paper we share scientific results related to the impact of different production systems, husbandry practices and pre-slaughter procedures associated to animal welfare and meat quality in Uruguayan conditions.

Immunocastration improves carcass traits and beef color attributes in Nellore and Nellore×Aberdeen Angus crossbred animals finished in feedlot

The objective was to examine the effects of immunocastration on carcass traits and meat quality of Nellore and Nellore×Aberdeen Angus male animals finished in feedlot. Surgically castrated, immunocastrated, and intact animals were finished in feedlot for 90 days. The animals were harvested, and carcass traits were evaluated. Carcasses were chilled, and one 2.5-cm steak was fabricated from Longissimus thoracis muscle. The steaks were individually vacuum packaged and frozen at -18 °C. Frozen steaks were thawed, and pH, instrumental color, cooking loss, and shear force were determined. Immunocastrated animals demonstrated greater (P<0.05) hot dressing percentage and cold dressing percentage than their surgically castrated counterparts. Furthermore, steaks from immunocastrated and surgically castrated animals exhibited greater redness (P<0.05) and lower darkness (P<0.05) than steaks from intact animals, indicating possible advantage in retailing. The results suggested that immunocastration may be utilized to improve carcass traits and beef color in feedlot-finished Nellore and Nellore×Aberdeen Angus males.

Immunocastration of Bos indicus x Brown Swiss bulls in feedlot with gonadotropin-releasing hormone vaccine Bopriva provides improved performance and meat quality

The objective of this study was to determine the effects of a GnRH vaccine on feedlot performance and meat quality in Bos indicus Zebu × Brown Swiss bulls. The study was a 2 × 2 factorial arrangement of treatments with 1,600 bulls allocated by BW into 4 groups of ≈ 400 animals. The GnRH vaccine (Bopriva) was injected on d 0 and 42, and anabolic implants given on d 0 (Component E-S) and d 84 (Synovex Choice). Group designations were: Con = placebo control; Imp = implants alone; Vac = GnRH vaccine alone; and Vac+Imp = GnRH vaccine together with implants. The second GnRH vaccination at d 42 resulted in elevated titers of IgG antibody and suppressed concentrations of testosterone in vaccinated groups (Vac and Vac+Imp) at d 56 (P < 0.001), with titers and suppressed testosterone persisting to d 147 (P < 0.001). Groups Vac and Vac+Imp had reduced testes weights at slaughter on d 147 (P < 0.001). Bulls in group Vac were not different in final BW, HCW, or ADG (d 42 to 147) relative to bulls in group Con. Bulls in group Vac+Imp had greater final BW than bulls in group Imp (P = 0.008) and greater BW than bulls in group Vac and group Con (P < 0.001). The HCW of Vac+Imp bulls was greater than the Vac or Con bulls (P < 0.001) but was not different to the Imp bulls (P = 0.294). Improved ADG was obtained by vaccination with the GnRH vaccine, in the presence of implants (group Vac+Imp compared with group Imp, P < 0.001) or absence of implants (group Vac compared with group Con, P = 0.028). Meat quality of bulls receiving the GnRH vaccine was improved irrespective of implant status, with a 1.6- to 2.6-fold increase in the proportion of bulls in groups Vac and Vac+Imp, respectively, grading as USDA Choice (P < 0.002) and with greater fat depth at the 12th rib (P < 0.001). Meat tenderness was improved in the vaccine groups (Vac and Vac+Imp) compared with groups Con and Imp (P < 0.004). Use of the GnRH vaccine Bopriva in Bos indicus × Brown Swiss bulls finishing in a feedlot under Mexican husbandry conditions can provide improved performance in combination with implants (increased BW and ADG) and improved meat quality, with or without implants, and in particular, better USDA carcass grading and loin fat cover.

Desempenho produtivo, características de carcaça e avaliação econômica de bovinos cruzados, castrados e não-castrados, terminados em pastagens de Brachiaria decumbens

Avaliou-se o efeito da castração sobre o desempenho produtivo e sobre as características de carcaça e realizou-se a avaliação econômica de bovinos terminados em pastagens de Brachiaria decumbens. Foram utilizados oito novilhos Canchim-Nelore com 14 meses de idade, sendo quatro animais castrados e quatro não-castrados, com média de peso corporal de 273,2kg. O delineamento foi inteiramente ao acaso com quatro repetições por tratamento. Os animais receberam, diariamente, 0,7% do PC de suplemento proteíco-energético e foram abatidos aos 26 meses de idade. O peso de abate e o ganho médio diário (GMD) diferiram entre castrados e não-castrados, com médias de 441,0 e 482,2kg e 0,6 e 0,7kg/dia, respectivamente. Não houve efeito da castração sobre as características avaliadas, com exceção do peso de abate, do peso da carcaça quente, 252,3 versus 229,9kg, da cor da carne, 3,25 versus 4,50 pontos e da espessura da gordura subcutânea, 0,6 versus 1,4mm, respectivamente, para não-castrados e castrados. A lucratividade por animal e por hectare foi de 14,5 e 15,8% para não-castrados e 4,5 e 5,8% para castrados, respectivamente. Sugere-se a utilização de bovinos não-castrados suplementados em pastagens de Brachiaria decumbens.

Reproductive characteristics of grass-fed, luteinizing hormone-releasing hormone-immunocastrated Bos indicus bulls1

Two field trials were conducted in Brazil to evaluate LHRH immunocastration of Bos indicus bulls (d 0 = 2 yr of age). In Study I, 72 bulls were assigned randomly to one of three treatment groups: LHRH0-immunized, castrated, and intact. Immunized animals (n = 25) received a primary and two booster injections of ovalbumin-LHRH-7 and thioredoxin-LHRH-7 fusion proteins on d 0, 141, and 287. Twenty-three bulls were surgically castrated on d 141, and 24 served as intact controls. All animals were slaughtered on d 385, at approximately 3 yr of age. In Study II, 216 bulls were assigned randomly to the same three treatments as in Study I; however, because of a drought in the area, bulls were kept on pasture an additional year, and a fourth treatment was added, in which one-half the LHRH-immunized bulls received an additional booster on d 639 (fourth immunization). All animals in Study II were slaughtered on d 741 (4 yr of age). Luteinizing hormone-releasing hormone antibodies increased following each immunization for immunized bulls, but they were not detectable in castrate or intact animals in either study. Consequently, scrotal circumference was suppressed in immunized bulls compared with intact controls in both studies. By d 287, serum concentrations of testosterone in LHRH-immunized bulls were decreased compared with intact controls (P < 0.01). In both studies, testes and epididymal weights at slaughter were greater (P < 0.01) for intact (500 +/- 17 and 60 +/- 2 g, respectively) than for immunized bulls (173 +/- 22 and 26 +/- 2 g, respectively) and fourth immunization bulls (78 +/- 23 and 20 +/- 2 g, respectively; Study II). At the end of each study, BW was greater (P < 0.01) for intact bulls than for castrated and LHRH-immunized animals. In these two studies, the efficacy of the LHRH fusion proteins to induce an effect similar to that of surgical castration was considered 92 and 93%, respectively. These data support the concept that immunocastration of bulls at 2 yr of age was successful and that it has practical application as a tool for producing grass-fattened bulls in Brazil.