Find ways to beat the heat
Farmers were warned to provide shelter for their livestock from storms and harsh weather, including the hot sun.
“Infrastructure that will enable livestock to ride out the storm, or get out of the rain and wind, would be an appropriate form of shelter,” said Dr. Diane Phillips, a veterinarian with the Victorian Department of Agriculture.
Diane said some farmers reported livestock losses due to severe storms and rain over the past few months.
“Vulnerable groups of livestock suffer from extreme weather events,” she said.
“Severe weather can include high winds, concentrated rain, hail and sudden temperature changes.”
Dianne said farmers should ensure their livestock are up to date on routine stock health management, including drenching, vaccinations and disease monitoring.
“Good health helps animals better adapt to changing weather conditions,” she said.
Richard Smith, extension officer for AgVic Dairy at Tatura in northern Victoria, said dairy farmers should have heat stress management programs in place for their herds.
“Heat stress has been shown to reduce milk production by up to 25 percent, reduce feed intake by up to 20 percent, and negatively impact fertility, artificial insemination, natural conception rates and calf rates,” Richard said.
“Modelling has shown that when shade is provided, there are 53 percent fewer cases of moderate heat stress and 86 percent fewer cases of severe heat stress.
“Shade, sprinklers and air movement allow the milk to drain faster and provide greater incentive for the herd to walk to the dairy.”
He also recommended installing a shade structure over the feeding pads.
The Ellinbank Research Farm is conducting research into the impact of extreme weather events on cow production, including heat stress.
DataGene also conducts research identifying genetic patterns for heat tolerance.
“Since 2018, DataGene has implemented the value of heat tolerance,” said Matt Shaffer, CEO of DataGene.
“DairyBio has done some additional work and this information will be available to farmers soon.
“Australia is the first country to offer a heat-tolerant ABV product, and there are a fair number of growers across Australia using it.
“Debate about its effectiveness is growing in the northern states of Australia and beyond.”
Dairy Australia has produced resources to help identify when cows may be in distress and how to manage this.
Cows begin to manage their core body temperature effectively when it is below 5°C and above 25°C.
In hot weather, cows use methods to effectively disperse heat including standing in water, shade or the breeze. They also pant and reduce their feed intake.
As air humidity and temperature increase, the effectiveness of evaporation strategies used by cows rapidly decreases.
Heat affects reproduction and milk production and can lead to severe heat stress that may lead to death.
Trees planted in pastures or trails can reduce radiative heat load by 50 percent or more. Orienting the long axis of the pasture from north to south will help maximize shade throughout the day.
The dairy yard is another place that gets hot – cows stand close together and their body temperatures can rise quickly.
Use sprinklers, hoses or flood washers to pre-wet your dairy yard an hour before the cows arrive for afternoon milking.
Finish morning milking before 9am and delay afternoon milking until after 5pm on hot days.
Consider a shade structure and fans as your next dairy yard upgrade. At the same time, make sure there is an adequate supply of food and water nearby.
In hot weather, cows’ daily water consumption doubles to 200 liters or more. Standing in a hot environment and eating grains increases their need for water.
Water makes up 85 percent of dairy cows’ production.
When nights are warm, this reduces the amount of heat a cow can dissipate throughout the night, and means her temperature will rise the next day.