Whole-genome scan reveals significant non-additive effects for sire conception rate in Holstein cattle

Abstract

BackgroundService sire has a considerable impact on reproductive success in dairy cattle. Most gene mapping studies for bull fertility have focused on additive effects, while non-additive effects have been largely ignored. The main goal of this study was to assess the relevance of non-additive effects on Sire Conception Rate (SCR) in Holstein dairy cattle. The analysis included 7.5 k Holstein bulls with both SCR records and 57.8 k single nucleotide polymorphism (SNP) markers spanning the entire genome.ResultsThe importance of non-additive effects was evaluated using an efficient two-step mixed model-based approach. Four genomic regions located on chromosomes BTA8, BTA9, BTA13 and BTA17 showed marked dominance and/or recessive effects. Most of these regions harbor genes, such as ADAM28, DNAJA1, TBC1D20, SPO11, PIWIL3 and TMEM119, that are directly implicated in testis development, male germ line maintenance, and sperm maturation.ConclusionsThis study provides further evidence for the relevance of non-additive effects in fitness-related traits, such as male fertility. In addition, these findings may point out new strategies for improving service sire fertility in dairy cattle via marker-assisted selection.

Genetic dissection of bull fertility in US Jersey dairy cattle

“…; Nicolini et al . ). This knowledge, however, cannot be transferred directly to Jerseys because this breed may exhibit differences in the pool of causative mutations, the extent of linkage disequilibrium, the phase between markers and causative mutations and the effects of the causative mutations.…”

“…Indeed, our recent study revealed significant dominance effects for SCR on Holsteins (Nicolini et al . ). Here, using an efficient two‐step mixed‐model‐based approach, we identified two genomic regions on BTA11 (2.6 Mb) and BTA25 (19.2 Mb) with significant recessive effects.…”

“…In addition, we recently reported significant non‐additive effects on BTA8, BTA9, BTA13 and BTA17 (Nicolini et al . ). Notably, all these genomic regions harbor genes with known roles in sperm physiology and male biology.…”

Genomic prediction of bull fertility in US Jersey dairy cattle

“…In fact, the relatedness encoded as spatial genetic distance between individuals is expected to capture some of the complexity of the genome, including nonadditive effects . It should be noted that Nicolini et al (2018) and Rezende et al (2018) have identified significant nonadditive effects underlying SCR in both Holstein and Jersey breeds. The better performance achieved by the Gaussian kernel can be due to its ability to capture the heterogeneous nature of this multi-breed reference population, including nonoverlapping major additive effects and important nonlinear effects.…”

“…On the other hand, and despite its importance, the genetic improvement of dairy bull fertility has received less attention. Our group has recently identified candidate genomic regions, individual genes, and biological processes underlying bull fertility in Holstein cattle (Han and Peñagaricano, 2016;Nicolini et al, 2018), as well as reported promising results for predicting Holstein SCR values using genomic data (Abdollahi-Arpanahi et al, 2017).…”