Bull fertility and semen quality are not correlated with dairy and production traits in Brown Swiss cattle

Abstract

Undisturbed reproduction is key for successful breeding of beef and dairy cattle. Improving reproductive ability can be difficult because of antagonistic relationships with other economically relevant traits. In cattle, thorough investigation of female fertility revealed unfavorable genetic correlations with various production phenotypes. However, the correlation between male reproductive ability and production traits remains poorly understood. Here, we investigated the genetic relationships among and between male fertility characteristics and economically relevant traits in a population of Brown Swiss cattle. We performed GWAS with imputed genotypes at nearly 12 million sequence variants for semen quality (sperm head and tail anomalies, motility, concentration, and volume), male fertility, and 57 production phenotypes. Allele substitution effects were then correlated on a trait-by-trait basis to estimate genetic correlations. Correlations between male reproductive characteristics and traits of economic value were small and ranged from −0.0681 to 0.0787. Among the semen quality parameters, sperm motility was negatively correlated with anomalies (head: r = −0.7083 ± 0.0002; tail: r = −0.7739 ± 0.0002) and volume (r = −0.1266 ± 0.0003), whereas volume was negatively correlated with concentration (r = −0.3503 ± 0.0002). Sire nonreturn rate was negatively correlated with sperm anomalies (head: r = −0.1640 ± 0.0002; tail: r = −0.1580 ± 0.0002) and positively correlated with motility (r = 0.1598 ± 0.0002). A meta-analysis of male reproductive traits identified 2 quantitative trait loci: a previously described region on chromosome 6 showed pleiotropic effects and a novel region on chromosome 11 was associated with sperm head anomalies. In conclusion, our results suggest that selection for economically important dairy and production phenotypes has little impact on semen quality and fertility of Brown Swiss bulls.

ProAKAP4 Semen Concentrations as a Valuable Marker Protein of Post-Thawed Semen Quality and Bull Fertility: A Retrospective Study

“…Reproductive failure consequences include increased calving intervals and decreased milk production, both leading to a loss of productivity and significantly increased economic costs for breeders [ 1 ]. Despite the male reproductive ability to fertilize having a significant economic impact on the dairy industry, the relationship between production and male fertility is not well understood [ 2 , 3 ]. The success of artificial insemination is affected by multiple variables, including the age of the bull, sperm quality of the frozen-thawed semen [ 4 , 5 , 6 , 7 ], the breeder’s technical skills, and the genetics of the herd, but also the quality criteria or standards of the semen proposed by the sire’s center [ 8 ].…”

“…Bull semen, which can allow genetic improvement, must be as fertile as possible to improve breeding rates [ 10 ]. Cattle fertility has a low heritability and the selection of bulls by their progeny’s fertility is difficult [ 3 , 11 , 12 ]. For sperm production, bulls are selected first on the basis of their genetic ability and fertility, and then the quality of the semen is tested for each pack of produced straws; sperm must be of good quality to maintain its fertility [ 13 ].…”

A 1-bp deletion in bovine QRICH2 causes low sperm count and immotile sperm with multiple morphological abnormalities

“…The differences in semen quality between carriers and non-carriers of the haplotype were only statistically significant for ejaculate volume (P = 0.017, Wilcoxon test). However, mixed model-based association testing between semen quality and dense markers did not reveal any QTL for semen quality in this genomic region [32]. Thus, we assume that the observed difference in ejaculate is due to factors other than the 1-bp deletion.…”

“…We examined historic semen quality records from a semen collection centre in Switzerland as part of our ongoing efforts to investigate inherited variation in male reproduction in Brown Swiss bulls [1,4,32]. Among 1343 Brown Swiss bulls that produced 70,990 ejaculates, we identified seven bulls from which all ejaculates (between 5 and 28 per bull) were rejected due to immotile (asthenozoospermia), morphologically abnormal (teratozoospermia), low concentration (oligozoospermia), or absence of (azoospermia) sperm, or a combination of these anomalies.…”

Deciphering the genetic basis of male fertility in Italian Brown Swiss dairy cattle

“…The significant region detected on BTA6 harbors the gene WDR19, a very strong candidate gene for service sire fertility in Brown Swiss cattle. Indeed, previous studies using bull fertility data from Swiss, German, and Austrian Brown Swiss cattle populations identified a synonymous variant in WDR19 significantly associated with various semen traits, including sperm motility and sperm abnormalities, and insemination success 21 , 22 . Gene WDR19 is a constituent of the intraflagellar transport complex that is essential for the physiological function of motile cilia and flagella, including sperm motility 23 .…”