Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2019
Publication Date: 6/27/2019
Citation: Cole, J.B., Null, D.J. 2019. Short communication: Phenotypic and genetic effects of the polled haplotype on yield, longevity, and fertility in US Brown Swiss, Holstein, and Jersey cattle. Journal of Dairy Science. 102(9):8247–8250. https://doi.org/10.3168/jds.2019-16530.
Interpretive Summary: This study examined the relationship of the polled (no horns) haplotype to phenotypic and genetic merit for traits of economic importance in U.S. Brown Swiss, Holstein, and Jersey cattle. Effects were generally small and few were statistically different from 0. Selection for hornless cattle in these three breeds should not have a detrimental effect on yield, fertility, or longevity.
Technical Abstract: Phenotypes from the December 2018 US national genetic evaluations were used to compute phenotypic effects of the polled haplotype in U.S. Brown Swiss (BS), Holstein (HO), and Jersey (JE) cattle on milk, fat, and protein yields, somatic cell score (SCS), single-trait productive life (PL), daughter pregnancy rate (DPR), heifer conception rate (HCR), and cow conception rate (CCR). Lactation records pre-adjusted for non-genetic factors and direct genomic values (DGV) were used to estimate phenotypic and genetic effects of the polled haplotype, respectively. No phenotypic or DGV effects were different from 0 for BS, but the sample size also was very small. Holstein carriers of the polled allele had higher phenotypic protein yields of 2.36 +- 0.69 kg (P < 0.0028) than non-carriers. Direct genomic values for milk and fat yields were also higher by 23.68 +- 7.30 and 1.04 +- 0.27 kg, respectively. There were no significant phenotypic effects in JE, although DGV for DPR were higher in polled carriers (2.85 +- 0.95 %; P < 0.0028). Selection for polled cattle in these three breeds should not have a detrimental effect on yield, fertility, or longevity.