Location: Genetics and Animal BreedingTitle: Using genomics to measure phenomics: Repeatability of bull prolificacy in multiple-bull pastures
|Cushman, Robert - Bob|
Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2021
Publication Date: 6/28/2021
Citation: Bennett, G.L., Keele, J.W., Kuehn, L.A., Snelling, W.M., Dickey, A.M., Light, D.E., Cushman, R.A., McDaneld, T.G. 2021. Using genomics to measure phenomics: Repeatability of bull prolificacy in multiple-bull pastures. Agriculture. 11(7). Article 603. https://doi.org/10.3390/agriculture11070603.
Interpretive Summary: Prolificacy of bulls used in multiple-bull pastures for commercial beef production is often unknown because sires of calves are not identified. Sires can be identified by genetic markers but costs are often thought to be too high. Knowing whether a bull sired many or only a few calves could be helpful if prolificacy is repeatable over years. Bulls in multiple-bull pastures and their calves were genotyped to determine their sires. Bulls were used one to four years. Repeatability of bull prolificacy was moderate to high. A less expensive way of estimating prolificacy based on pooling DNA from calves was simulated incorporating pooling errors estimated from previous studies. It resulted in accurate estimates of bull prolificacy. Knowing a bull’s prior prolificacy obtained at a lower price could help predict future prolificacy for managing the breeding herd. More available estimates of bull prolificacy could also result in more on-farm and ranch research on breeding herd management as well as improved bull prolificacy through selection.
Technical Abstract: Phenotypes are necessary for genomic evaluations and management. Sometimes genomics can be used to measure phenotypes when other methods are difficult or expensive. Prolificacy of bulls used in multiple-bull pastures for commercial beef production is an example. A retrospective study of 79 bulls aged 2 and older used 141 times in 4–5 pastures across 4 years was used to estimate repeatability from variance components. Traits available before each season’s use were tested for predictive ability. Sires were matched to calves using individual genotypes and evaluating exclusions. A lower-cost method of measuring prolificacy was simulated for five pastures using the bulls’ genotypes and pooled genotypes to estimate average allele frequencies of calves and of cows. Repeatability of prolificacy was 0.62 ± 0.09. A combination of age-class and scrotal circumference accounted for less than 5% of variation. Simulated estimation of prolificacy by pooling DNA of calves was accurate. Adding pooling of cow DNA or actual genotypes both increased accuracy about the same. Knowing a bull’s prior prolificacy would help predict future prolificacy for management purposes and could be used in genomic evaluations and research with coordination of breeders and commercial beef producers.