Victorian dairy farmers are being urged to do all they can to keep their cattle cool as hot humid conditions cross the state.
Temperatures are forecast to hit over 40C, at Mildura, in the north-east, to 38C in Melbourne.
Dairy Australia has a that gives farmers advice on how to prevent heat stress and a loss of milk production in their herd.
Dairy Australia consultant, Steve Little, says the website also provides a new tool that factors in the effects of wind speed and the amount of direct solar radiation on cattle.
He says it will help farmers make those day-to-day decisions about how to care for the cows.
"How do I change my paddock rotation? Should I have the sprinklers on in the dairy in the morning as well as the afternoon milking," he said.
"How hot it is and what the relative humidity is, the amount of wind, the amount of air movement because that really helps with evaporation."
© ABC 2012
13:25 EDT After a fairly cloudy morning, Sydney's skies are clearing nicely for a starry but cool night for Carols at the Domain.