Summer conditions see dairy farmers in hot areas looking at ways to help cows handle hot, humid weather.
December's release of Australian Breeding Values from DataGene was a good opportunity for farmers to think about adding breeding to their tool kit for managing heat in dairy herds.
Michelle Axford, from DataGene, said the Heat Tolerance ABV enabled dairy farmers to identify high genetic merit animals that were more able to tolerate hot conditions with less impact on milk production.
"Environment and management will always be important with managing hot conditions, but genetics also plays a role and farmers are rapidly having a lot more breeding choices," Mrs Axford said.
"When the Heat Tolerance ABV was released in 2017 there were very few high genetic merit bulls with more than 100 for Heat Tolerance. Now there are more than 275 Holstein Good Bulls that meet those criteria. And the top two proven Holstein bulls for BPI are average or above average for heat tolerance."
To breed for improved heat tolerance, look for bulls with the combination of a high Balanced Performance Index (BPI) and a Heat Tolerance ABV of greater than 100. If using the Good Bulls App, set a filter to screen out bulls with a Heat Tolerance ABV below 100.
"Heat tolerance is favourably linked with fertility and unfavourably linked with production, so it's important to look for the exceptional bulls that are strong for both Balanced Performance Index or production as well as heat tolerance. And always use a team of bulls to spread risk," Mrs Axford said.