Sources of sire-specific genetic variance for birth and weaning weight in Bruna dels Pirineus beef calves

Abstract

This research investigated two sources of sire-specific genetic effects on the birth weight (BWT) and weaning weight (WWT) of Bruna dels Pirineus beef calves. More specifically, we focused on the influence of genes located in the non-autosomal region of the Y chromosome and the contribution of paternal imprinting. Our analyses were performed on 8130 BWT and 1245 WWT records from 12 and 2 purebred herds, respectively, they being collected between years 1986 and 2010. All animals included in the study were registered in the Yield Recording Scheme of the Bruna dels Pirineus breed. Both BWT and WWT were analyzed using a univariate linear animal model, and the relevance of paternal imprinting and Y chromosome-linked effects were checked by the deviance information criterion (DIC). In addition to sire-specific and direct genetic effects, our model accounted for random permanent effects (dam and herd-year-season) and three systematic sources of variation, that is, sex of the calf (male or female), age of the dam at calving (six levels) and birth type (single or twin). Both weight traits evidenced remarkable effects from the Y chromosome, whereas paternal imprinting was only revealed in WWT. Note that differences in DIC between the preferred model and the remaining ones exceed 39 000 and 2 800 000 DIC units for BWT and WWT, respectively. It is important to highlight that Y chromosome accounted for ,2% and ,6% of the total phenotypic variance for BWT and WWT, respectively, and paternal imprinting accounted for ,13% of the phenotypic variance for WWT. These results revealed two relevant sources of sire-specific genetic variability with potential contributions to the current breeding scheme of the Bruna dels Pirineus beef cattle breed; moreover, these sire-specific effects could be included in other beef cattle breeding programs or, at least, they must be considered and appropriately analyzed.Keywords: Bruna dels Pirineus, sire-specific genetic variance, birth weight, weaning weight ImplicationsDespite the fact that sire-specific genetic effects are typically ignored in genetic evaluation models, their real impact remains almost unknown in livestock species. Both Y chromosomerelated effects and paternal imprinting effects were evaluated on birth and weaning weight (WWT) in the Bruna dels Pirineus beef cattle breed. Whereas Y chromosome effects influenced both traits and accounted for ,2% and 6% of the phenotypic variance, respectively, paternal imprinting effects restricted to WWT (,13% of the phenotypic variability). Our results highlighted the relevance of these sire-specific sources of variation in beef cattle, and provided relevant information to optimize genetic evaluation models for weight traits.

Consequences of paternally inherited effects on the genetic evaluation of maternal effects

“…Furthermore, when both effects were fitted in the estimation model (AMS), the maternal effects contributed less to the total variation than the paternal gametic effects. A similar reduction in the maternal contribution on weaning weight was also found in the Bruna dels Pirineus beef cattle breed when paternal gametic effects were considered in the estimation model [ 33 ]. Indeed, more evidence for the presence of parent-of-origin variation is derived from the fact that when Model SD was used, a very low correlation between paternal and maternal gametic effects was obtained.…”

High energy diet of beef cows during gestation promoted growth performance of calves by improving placental nutrients transport

“…However, lower maternal energy intake decreases the birth weight and immunity of calves. In beef cattle production, higher birth weight of calves is favorable to future productivity ( 31 ). On the other hand, high energy diet during late gestation can induce difficult labor.…”