Managing cow heat stress to cut production losses

 

Big producing Australian dairy cows are more susceptible to heat stress than ever before, but scientists have proven that a multifaceted approach is the best way to stem milk losses.

This comes after University of Melbourne researchers at its Dookie campus in northern Victoria were able to limit the effects of heat stress to a production decline of only 11 per cent, thanks to employing a range of heat mitigating practices.

Previous industry research in climate-controlled chambers recorded milk yield drops of up to 30 per cent in heat stressed dairy cows.

The 120- head Holstein herd at Dookie was milked in a robotic dairy and monitored by researchers for signs of heat stress across the summer of 2018-2019.

The University of Melbourne Faculty of Veterinary and Agricultural Sciences Senior Lecturer Dr Surinder Singh Chauhan was the research project leader.

He said the herd, which included early, mid and late lactation cows, had access to trees for shade, water, sprinklers and misting fans.

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Approaching the heat management from different angles was the key to balancing animal welfare while maintaining production.

“There’s no single strategy that is going to work,” he said. “You have to help cows reduce their direct exposure to heat, that’s why shade is really important, but you also help the animal to be able to dissipate heat from their body. Providing them with shade and water enables them to lose heat from their body, by cooling their body down, but there’s also their metabolic heat production which is managed by their nutrition. It’s the three things in combination.”

Dr Chauhan said heat stress was an evolving issue in the dairy industry because of the rising number, and duration, of heatwaves as well as the continued selection for milk production of modern dairy cows.

He said cows bred for higher milk production were not necessarily the best at handling hot conditions and farmers needed tools to maintain optimal animal welfare and milk production while waiting for the outcomes from recent genetic heat stress solutions.

 

Last year the Australian dairy industry released the world first Heat Tolerance Australian Breeding Value, developed by DairyBio– a joint initiative between the Victorian Government and Dairy Australia, with funding from the Australian Department of Agriculture and Water Resources.

The Heat Tolerance ABV allows farmers to identify animals with a greater ability to tolerate hot conditions with these conditions having less of an impact on milk production.

As part of the study at Dookie, researchers observed that almost 95 per cent of the cows were seeking shade and had suspended grazing on days where the temperature was 32 degrees Celsius or more. Up to 60 per cent of the animals chose preferential access to water on these days too.

Providing shade and a climate-controlled environment to maintain dry matter intake during hot conditions underpinned many farmer queries to dairy shed installation company Entegra.

Entegra marketing coordinator Adam Smith has fielded lots of queries from dairy farmers across the country seeking improved productivity and animal welfare through housed-cow farming.

 

“Entegra has built several barns in the past year and these farmers have calculated the return on their investment through increased production and less feed wastage,” he said. “They know their herd will be protected from the summer heat in a shed and this means they have more energy to put into milk production.”

 

Dairy farmers looking to make the most of the Woolworths Dairy Innovation Fund, which offers grants of up to $100,000, have also contacted Entegra about shed construction.

These applications close on February 16, but Mr Smith said Entegra was prepared to work fast to prepare a quote for any farmers considering applying.

Queensland dairy farmers Chad and Carita Parker and their children Klara 10 and Cooper 6 installed an Entegra Ridgeback barn just over three years ago.

They haven’t looked back.

“It’s easier to milk 600 cows with a shed and infrastructure than it was to milk 200 without,” Chad said.

The couple first became aware of Entegra sheds at International Dairy Week in Victoria, interested in the benefits that housed cow farming would deliver for both heat stress and wet conditions.

At Kenilworth, on Queensland’s Sunshine Coast, where they farm, summer temperatures can get to 40 degrees Celsius and humidity’s also an issue.

They saw immediate results from the barn, which lifted profitability, from housing their Jersey herd.

“The test (butterfat and protein) went up immediately,” Chad said. “There was a 0.2 per cent average increase across the fat and protein. They were eating more feed, obviously because they were more comfy. We had budgeted on the milk (litres) going up but didn’t budget on the test going up.”

 

Inside the climate controlled Ridgeback ™ Dairy Barn which has a concave roof that increases air exchange by at least an additional 20 per cent

 

In November, the Australian Lot Feeders’ Association estimated 60 per cent of the industry feedlot capacity had shade for animals.

According to ALFA there are 400 accredited feedlots in Australia, 60 per cent are in Queensland. At any one time the peak industry body said 2-3 per cent of Australia’s total cattle population are in feedlots.

From January to September 2020 there was slightly more than 1 million cattle on feed in Australia

With a goal of installing shade in all feedlots by 2026, ALFA is working with the livestock industry on research to demonstrate the benefits of shade for individual enterprises and the entire industry.

It’s also provided feedlot operators with information on shade design, standards and construction while highlighting financing opportunities through Federal and State low interest loans and asset write-off incentives.

 

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