The Macalister Research Farm was the venue for a field day to discuss heat stress in cows and how to mitigate hot weather impacts in the herd.
The research farm is 64 hectares, milking 234 cows in a herringbone dairy.
The farm is heavily vegetated with shade trees and irrigated by sprinklers and flood irrigation.
“We’ve got quite a lot of trees around here,” Jasmine said.
“We’ve got a lot of gum trees and cypress trees, and then we’ve got quite a lot of tree breaks.
“Having the shade helps us a lot.”
Unfortunately, the old dairy was built without consideration for shade in the yard.
During hot weather, Jasmine has monitored the air temperature, and chosen to milk the herd early in the morning, then delay afternoon milking until late.
“On hot days this summer, I just kept walking out to the dairy and going, the air doesn’t feel right yet,” she said.
“I didn’t have a time in mind. We normally start milking cows at 3pm, but we didn’t get cups on until 5pm.
“Before then we hosed the yard to cool it down before the cows arrived.”
Jasmine has also chosen strategic paddocks with shade for the herd to graze and shelter in during the day.
“We also keep them in paddocks closer to the dairy so they don’t have to walk very far to and from the dairy,” she said.
“We also opened up a second paddock, that had already been grazed, to provide a second water trough for the cattle. That meant the herd could access water more easily.”
Veterinarian Lauren Foster said environmental changes had the largest positive effect on cows during hot weather.
“Over time, cows will get better at tolerating hot weather if it’s hotter all the time,” she said.
“But when you get a few hot days, then it cools down, then heats up again, that’s when you’ll really see cows knocked around.
“The best thing you can do is invest in shade for your cows.
“Changing your breeding for better heat stress, that’s going to take a long time to see the effects of, and has about a one per cent difference.
“Changing your feeding strategy has about a five per cent difference.
“The infrastructure you invest in to provide shade, all that type of stuff is what makes the most difference for your cows on a day-to-day term and long term.
“Get them into paddocks with shade and a couple of water troughs.
“And cool down the dairy platform before the cows arrive, by washing it down, using sprinklers, fans and shade infrastructure such as shade sails or roofs,” Dr Foster said.
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