Two-, three- and four-breed rotational crossbreeding of beef cattle: reproductive traits

Non-antibiotic approaches for disease prevention and control in beef and veal production: a scoping review

Livestock producers are encouraged to reduce the use of antibiotics belonging to classes of medical importance to humans. We conducted a scoping review on non-antibiotic interventions in the form of products or management practices that could potentially reduce the need for antibiotics in beef and veal animals living under intensive production conditions. Our objectives were to systematically describe the research on this broad topic, identify specific topics that could feasibly support systematic reviews, and identify knowledge gaps. Multiple databases were searched. Two reviewers independently screened and charted the data. From the 13,598 articles screened, 722 relevant articles were charted. The number of relevant articles increased steadily from 1990. The Western European research was dominated by veal production studies whereas the North American research was dominated by beef production studies. The interventions and outcomes measured were diverse. The four most frequent interventions included non-antibiotic feed additives, vaccinations, breed type, and feed type. The four most frequent outcomes were indices of immunity, non-specific morbidity, respiratory disease, and mortality. There were seven topic areas evaluated in clinical trials that may share enough commonality to support systemic reviews. There was a dearth of studies in which interventions were compared to antibiotic comparison groups.

Detection of Bovine TMEM95 p.Cys161X Mutation in 13 Chinese Indigenous Cattle Breeds

Simple Summary

Chinese indigenous cattle are economically important cattle breeds for animal husbandry development. The promotion and development of Chinese cattle breeds is essential. A previous study found that a nonsense mutation (rs378652941, c.483C > A, p.Cys161X) in bovine transmembrane protein 95 gene (TMEM95) seriously reduced reproductive performance in male Fleckvieh cattle; therefore, this locus was considered a candidate genetic marker in bovine marker-assisted selection (MAS) breeding. Until now, no study has identified this mutation in Chinese cattle breeds. Herein, we detected this c.483C > A mutation in 13 Chinese cattle breeds. Importantly, we found that this mutation did not exist at this locus in our analyzed breeds. Interestingly, we first identified a frameshift insertion/deletion (indel) mutation (NC_037346.1: g.27056998_27057000delCT) in the bovine TMEM95 gene in 11 cattle breeds. Together, the results of this study suggest that the mutation c.483C > A cannot serve as a genetic marker for molecular breeding among Chinese indigenous cattle breeds.

Abstract

Chinese indigenous cattle breeds have abundant genetic resources, which are valuable for the molecular breeding of cattle around the world. Thus, identifying important candidate genes and their genetic markers is very important for cattle molecular breeding. A previous study found that a nonsense mutation (rs378652941, c.483C > A, p.Cys161X) in the bovine transmembrane protein 95 gene (TMEM95) seriously reduced the reproductive performance in bulls, but few studies have detected this mutation in Chinese indigenous cattle breeds. Since the mutation c.483C > A may serve as a potential genetic marker for selecting higher fertility bulls, in the present study, using tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR), forced PCR restriction fragment length polymorphism (forced PCR-RFLP), and DNA sequencing methods, the mutation c.483C > A was detected in 765 individuals from 13 Chinese cattle breeds. However, the results showed that this mutation did not exist at this locus in our analyzed breeds. Interestingly, we identified a newly frameshift insertion/deletion (indel) mutation (NC_037346.1: g.27056998_27057000delCT) in the bovine TMEM95 gene in 11 cattle breeds, which changed the location of the termination codon and changed the 16 amino acids in the C-terminal to 21 amino acids. Combined with previous studies, our study provides evidence that in Chinese cattle breeds the mutation c.483C > A cannot be used as a genetic marker in molecular breeding.

Genetic parameters for calving rate and calf survival from linear, threshold, and logistic models in a multibreed beef cattle population1

Generalized mixed linear, threshold, and logistic sire models and Markov chain, Monte Carlo simulation procedures were used to estimate genetic parameters for calving rate and calf survival in a multibreed beef cattle population. Data were obtained from a 5-generation rotational crossbreeding study involving Angus, Brahman, Charolais, and Hereford (1969 to 1995). Gelbvieh and Simmental bulls sired terminal-cross calves from a sample of generation 5 cows. A total of 1,458 cows sired by 158 bulls had a mean calving rate of 78% based on 4,808 calving records. Ninety-one percent of 5,015 calves sired by 260 bulls survived to weaning. Mean heritability estimates and standard deviations for daughter calving rate from posterior distributions were 0.063 +/- 0.024, 0.150 +/- 0.049, and 0.130 +/- 0.047 for linear, threshold, and logistic models, respectively. For calf survival, mean heritability estimates and standard deviations from posterior distributions were 0.049 +/- 0.022, 0.160 +/- 0.058, and 0.190 +/- 0.078 from linear, threshold, and logistic models, respectively. When transformed to an underlying normal scale, linear sire, mixed model, heritability estimates were similar to threshold and logistic sire mixed model estimates. Posterior density distributions of estimated heritabilities from all models were normal. Spearman rank correlations between sire EPD across statistical models were greater than 0.97 for daughter calving rate and for calf survival. Sire EPD had similar ranges across statistical models for daughter calving rate and for calf survival.

Evaluation of beef cattle genotypes and estimation of direct and maternal genetic effects in a tropical environment. 3. Fertility and calf survival traits

Data from a crossbreeding experiment were analysed to compare various breeds in a tropical environment. Data included male fertility [scrotal circumference at yearling age (YSC) and at 18 months of age (FSC)], female fertility [calving success (CS) and days to calving (DTC)], and calf survival [survival of calf up to 1 week after birth (WKS) and up to weaning (PWS)] traits. Male fertility traits were analysed as traits of the progeny generation, whereas female fertility and calf survival traits were analysed as traits of the dam (parental generation). Tropically adapted British breed bulls and taurine crossbreds (British × Sanga) had higher YSC and FSC than Zebu and its crosses when adjusted for their body weights. Large negative direct and maternal additive effects on scrotal circumference for Zebu relative to the British breed also suggested reduced scrotal circumference and fertility in Zebu and Zebu-derived crosses. Direct dominance effects for YSC and FSC were only significant when an adjustment for body weight was not included in the model, emphasising that the heterosis observed was only due to the increased body weight. In general, CS was higher in non-lactating cows and maiden heifers than in lactating cows. The advantage to crossbred genotypes was more pronounced in lactating cows. Among lactating purebreds, CS was significantly (P < 0.05) higher in Belmont Adaptaur (Hereford–Shorthorn, HS) than in Belmont Red (AX), Belmont Brahman cross (BX), and Brahman (Bh). Lactating crossbreds with a common dam breed of HS, AX, BX, and Bh had 19, 33, 21, and 14% greater CS than their respective purebreds. Boran-sired crossbred dams had higher CS than Brahman-sired crossbreds, indicating higher fertility levels of Borans. Significant direct dominance effect for CS in lactating taurine–indicine crosses and in non-lactating taurine–taurine crosses signifies the importance of use of appropriate breed crosses in improving female fertility. Significantly negative (desirable) direct dominance effects for DTC in indicine–indicine and taurine–indicine crosses suggest an advantage from crossbreeding in achieving early calvings. High mortalities were recorded in calves born to HS dams from matings with Brahman bulls due to dystocia. This resulted in low WKS and PWS for HS dam breeds. All additive and dominance effects for calf survival traits were non-significant except for the direct dominance effect in taurine–indicine crosses for PWS. Moderate percentage heterosis estimates in lactating cows for CS and desirable, significant, but low percentage heterosis estimates for DTC were observed. Percentage heterosis estimates for calf survival traits were low and non-significant.