Abstract

Climate change will become increasingly problematic for grazing cattle, with heat stress impacting both animal welfare and productivity. Genetic strategies are available to mitigate heat stress, some of which such as crossbreeding, have already been tested in tropical climates. Heat tolerance is a heritable trait in dairy cattle and genetic progress can be achieved using genomic selection, an approach adopted in Australia. Another strategy is to introgress the SLICK genetic variant from Senepol beef cattle into dairy cattle. This enables a 0.5 to 1.0 °C advantage in rectal and ruminal temperature, relative to control cows, when under a mild heat load. This variant has already been introduced into breeds of beef cattle by gene editing, an approach which promises to greatly accelerate gene introgression for single gene traits and lessen the potential impact of introgression on inbreeding in a population. Keywords: heat tolerance, dairy cattle, SLICK, breeding

Donkersloot, EG, Worth GM, McNaughton LR, Yeates A, Davis SR, and Spelman RJ

New Zealand Journal of Animal Science and Production, Volume 83, Rotorua, 8-10, 2023