A Whole-genome Association Analysis of Noncompensatory Fertility in Holstein Bulls

Increasing fertility in dairy cattle is an important goal. Male infertility represents a part of the overall infertility in dairy cattle and can be partitioned into compensatory and noncompensatory components, where compensatory refers to infertility that can be overcome by increasing sperm number and noncompensatory infertility represents the remainder, presumably due to molecular and genomic defects. Through estimation of single nucleotide polymorphism (SNP) association with noncompensatory bull fertility, it is possible to identify regions of the genome influential to this trait. Use of this information in selection can allow for an increase in cattle fertility, resulting in economic benefits. In this study, high-density SNP genotypes and noncompensatory fertility data from 795 Holstein sires were used to examine SNP associations with fertility. A Bayes B analysis was performed to develop information for genomic selection and to identify genomic regions associated with noncompensatory fertility. A cross-validation approach was used to assess the effectiveness of the models within the original set of 795 bulls. Correlations of predicted and observed fertility values were approximately 0.145 in cross-validation.