Multiple trait genomic evaluation of conception rate in Holsteins

Area of Science:

• Animal breeding and genetics
• Reproductive biology
• Dairy science

Background:

• Conception rate (CR) is a crucial trait in dairy cattle breeding.
• Accurate genetic evaluations are needed to improve CR in US Holsteins.
• Traditional methods may not fully leverage all available data.

Purpose of the Study:

• To assess the feasibility and accuracy of using integrated phenotypic, pedigree, and genomic data for CR genetic evaluations.
• To compare the performance of a single-step procedure (SSP) with regular BLUP.
• To estimate genetic parameters for CR across parities.

Main Methods:

• Utilized a national dataset of artificial inseminations in US Holsteins.
• Employed regular BLUP and a unified single-step procedure (SSP) for genetic evaluations.
• Estimated genetic parameters (heritability, genetic correlations) for CR in the first three parities using New York State data.

Main Results:

• Heritability estimates for CR were approximately 2%, with high genetic correlations (>0.73) between parities.
• The SSP achieved R(2) values nearly double those of regular BLUP.
• SSP computation was feasible within 2 hours, though 33% slower than regular BLUP.

Conclusions:

• A multiple-trait evaluation of CR using the SSP is both feasible and advantageous.
• The SSP offers superior accuracy for genetic evaluations of conception rate.
• Integrating diverse data sources enhances breeding program effectiveness.