Understanding heat stress in livestock and ways to prevent it

17 February 2026

Dr Jeff Cave, Senior Veterinary Officer

As warm summer temperatures continue across Victoria, farmers are urged to take extra care of their livestock to prevent heat stress, a condition that can severely impact both animal welfare and production.

Cattle are most comfortable in temperatures between 5°C and 25°C, while adult pigs prefer a narrower range of just 18°C to 20°C.

High-producing animals, such as dairy cows, are especially vulnerable, and poultry have been known to succumb to extreme heat on scorching days.

When the mercury rises, animals divert energy to cooling themselves, which can lead to reduced feed intake, slower weight gain, and lower milk production. Fertility may also decline.

Humidity adds to the problem, intensifying heat stress even at moderate temperatures.

Signs of heat stress include panting, standing rather than lying down, seeking shade, increased drinking, and decreased appetite.

Farmers are advised to check their stock daily during hot weather and take steps to keep them comfortable.

Key recommendations include:

• provide unlimited access to shade or shelter

• ensure cool, clean drinking water is always available

• avoid animal movement during the hottest part of the day or on extreme heat days

• offering high-quality feed in the cooler evening hours

• have a fire plan ready and ensure someone checks on stock if you're away.

By making small adjustments to daily management, producers can significantly reduce the impact of heat stress and protect both animal welfare and productivity.

For more advice, contact your local veterinarian, Agriculture Victoria animal health staff, or in New South Wales, your Local Land Services.

For information bushfire support visit www.agriculture.vic.gov.au/bushfires

For information on drought support visit www.agriculture.vic.gov.au/drought