Unraveling genetic sensitivity of beef cattle to environmental variation under tropical conditions

Abstract

Background Selection of cattle that are less sensitive to environmental variation in unfavorable environments and more adapted to harsh conditions is of primary importance for tropical beef cattle production systems. Understanding the genetic background of sensitivity to environmental variation is necessary for developing strategies and tools to increase efficiency and sustainability of beef production. We evaluated the degree of sensitivity of beef cattle performance to environmental variation, at the animal and molecular marker levels (412 K single nucleotide polymorphisms), by fitting and comparing the results of different reaction norm models (RNM), using a comprehensive dataset of Nellore cattle raised under diverse environmental conditions. Results Heteroscedastic RNM (with different residual variances for environmental level) provided better fit than homoscedastic RNM. In addition, spline and quadratic RNM outperformed linear RNM, which suggests the existence of a nonlinear genetic component affecting the performance of Nellore cattle. This nonlinearity indicates that within-animal sensitivity depends on the environmental gradient (EG) level and that animals may present different patterns of sensitivity according to the range of environmental variations. The spline RNM showed that sensitivity to environmental variation from harsh to average EG is lowly correlated with sensitivity from average to good EG, at both the animal and molecular marker levels. Although the genomic regions that affect sensitivity in harsher environments were not the same as those associated with less challenging environments, the candidate genes within those regions participate in common biological processes such as those related to inflammatory and immune response. Some plausible candidate genes were identified. Conclusions Sensitivity of tropical beef cattle to environmental variation is not continuous along the environmental gradient, which implies that animals that are less sensitive to harsher conditions are not necessarily less responsive to variations in better environmental conditions, and vice versa. The same pattern was observed at the molecular marker level, i.e. genomic regions and, consequently, candidate genes associated with sensitivity to harsh conditions were not the same as those associated with sensitivity to less challenging conditions. Electronic supplementary material The online version of this article (10.1186/s12711-019-0470-x) contains supplementary material, which is available to authorized users.

Development of a genetic evaluation for hair shedding in American Angus cattle to improve thermotolerance

“…In the four phenotypic regressions of calf weaning weight on dam hair shedding score, dam hair shedding while grazing toxic fescue was estimated to have the largest effect on adjusted weaning weight, but not on unadjusted weight. When contemporary grouping is fitted as a fixed effect in BLUP, the resulting contemporary group solution can be interpreted as a metric of environmental stress [ 52 , 53 ]. Larger contemporary group solutions indicate a greater advantage to the phenotype from the environment, including plane of nutrition and management practices.…”

Powerful detection of polygenic selection and evidence of environmental adaptation in US beef cattle

“…Ideally, we could exploit within breed variation to produce pure Bos taurus individuals suited to the full range of environments in the US without sacrificing performance for growth, maternal, or carcass traits. Previous work has identified the presence of extensive GxE in beef cattle populations [78][79][80] , but limited work exploring the genomic basis of local adaptation has occurred 81 .…”

Uncovering Sub-Structure and Genomic Profiles in Across-Countries Subpopulations of Angus Cattle

“…This genomic region was previously identified as a QTL associated with resistance to viral load in Holstein cattle 58 , and it comprises genes that showed differential expression between susceptible and resistant hosts to cattle tick (KIF3A) 25 , mange infested and uninfested animals (IL4, IL5 and IL13) 59 , healthy and with mastitis cows (IL4) 60 . In addition, this selection signature was associated with the adaptation of taurine breeds to harsh environments 61 and of indicine breeds to not so harsh, but still challenging environmental conditions 62 .…”