Genetic evaluation for heat tolerance in Angus cattle

Because beef cattle are raised in extensive conditions, growth can vary across production environments. Within-breed genotype x environment interactions have been reported for weaning weight and yearling weight (Butts et al., 1971; Bertrand et al., 1987). When Hereford cattle were adapted to the Florida or the Montana climate, calves had 20 lb heavier weaning weights when grown in the environment they were adapted to (Butts et al., 1971). Genetic lines within a breed differ in their adaptability to specific regions. Thus, selection would be more accurate when using genetic predictions specific to a given environment.