By Agriculture Victoria district veterinary officer Dr Jeff Cave
As we head into the height of summer, heat stress in livestock can become a major issue both for production levels and animal welfare.
By making some minor management changes and taking a little extra care of your livestock in extreme hot weather, the effects of heat stress can be substantially reduced.
The ideal temperature range for cattle is between 5°C and 25°C, and for adult pigs is 18°C to 20°C.
High producing livestock, such as dairy cows, are the animals most sensitive to heat stress.
Poultry have been known to perish due to heat stress on very hot days.
As temperatures rise, livestock divert energy away from production to cool themselves. This is done via heat loss through their skin surface and respiratory tract.
Feed intake is also reduced and a decrease in milk production may be observed.
Humidity also plays a significant role, and for any given temperature, the degree of heat stress increases as the relative humidity increases.
Heat stressed livestock will seek out shade, drink more, eat less, stand rather than lay, pant, produce less milk and potentially be less fertile.
On hot days, livestock should be given access to shade and good quality, cool drinking water.
High quality feed should be given during the evening when it is cooler, and livestock are likely to have better intakes.
The yarding and moving of livestock should be avoided during the hottest part of the day. Your fire plan may need to be enacted on such days.
For further information, contact your local veterinarian, Agriculture Victoria veterinary or animal health officer, or go to: agriculture.vic.gov.au/extremeheat
For more information, visit: coolcows.dairyaustralia.com.au/