Avoid heat stress in dry cows

By Sophie Baldwin

A Murray Dairy workshop on the effects of heat stress in dry cows held last week delivered some surprising information to the farmers in attendance, offering some food for thought when it comes to management.

Presented by Geoff Dahl from the University of Florida, the workshop was held at Allenby Pastoral Co at Bamawm.

Mr Dahl is involved in the university’s Department of Animal Science and has been studying the effects of heat stress on cows for years.

He said while most farmers were well aware of the effects on the milking herd, dry cows were often forgotten.

‘‘The effects of heat stress on a dry cow will have significant impacts on the next lactation and the next generation,’’ Mr Dahl said.

Studies by the University of Florida have shown heat stress can reduce production in a lactating cow by 5litres/day and perhaps even more interestingly, calves born to heat-stressed cows show reduced growth rates and go on to produce less milk as mature cows.

Mr Dahl said he believed preventing heat stress in dry cows was even more important than in the milking herd.

‘‘The response on heat-stressed calves is there for life.

‘‘A heat-stressed calf in-utero will never catch up and that is passed down onto their progeny — they always seem to be sitting on the lower limit of normal.

‘‘I would be developing on-farm infrastructure to keep cows cool as my priority.

‘‘You will always get the most bang for your buck by keeping dry cows cool,’’ he said.

He said while shade was certainly better than nothing, fans and sprinklers were preferable. He urged farmers to bring their dry cows up with the milking herd and put them under the sprinkler as well.

Calivil dairy farmer Jade Clymo said the presentation had definitely given him pause for thought when it came to managing his dry cows.

‘‘It certainly is a lot more important than I realised and this has given me a lot to think about when it comes to the future management of my dry cows,’’ Mr Clymo said.