With temperatures expected to surpass 30° in the coming days, the ongoing hot weather – while welcomed by many farmers – can cause heat stress to livestock and significant vigilance is advised.
Generally speaking, cattle enjoy the warm weather; but, relentless heat can also have a negative impact on livestock, causing heat stress, and particular attention should be given to cows and young stock such as calves.
Heat stress occurs when an animal’s heat load is greater than its capacity to lose heat.
The most visible symptoms tend to be elevated breathing rates, however, increased water intake and sweating, along with decreased feed intake, are other symptoms.
Key symptoms:
- Increased breathing rate;
- Increased water intake;
- Increased sweating;
- Decreased milk production;
- Change in milk composition – milk fat and protein percentages drop (seen in dairy cows);
- Change in blood hormone concentration (increased prolactin);
- Changed behaviour – crowding, heavy breathing and standing next to a water trough.
Preventing heat stress
To help prevent heat stress occurring, farmers must pay particular attention to water, feed, shade and management.
On a really hot day, cows can drink anywhere up to 110L/day and they can typically drink at a rate of 14L/minute from a trough.
With this in mind, farmers are encouraged to carefully consider trough location, as cattle don’t like to walk more than 250m to get a drink.
It’s also important to focus on the feed source.
Offering feed with a high fibre content can increase the heat of fermentation in the rumen, thus increasing the heat load of livestock.
Cattle should be given preferential access to paddocks with shade from trees and tall hedges during periods of hot weather.
If moving or handling cattle, farmers should minimise the time cattle are in holding yards and to reduce handling stress.
Where cattle do become affected by heat stress, it’s advisable to isolate the most severely affected animals and provide shade and cooling.