Heat Stress in Dairy Cows

Following the record high average mean temperatures in June, and the heatwave of summer 2022 heat stress in dairy cows is at the forefront of everyone’s minds.

Heat stress occurs in dairy cows when they have more heat than they can get rid of, and this leads to more stress, lower milk production and a higher rate of diseases. Temperature and humidity levels determine when a cow may start feeling heat stressed.  The ideal temperature for a dairy cow is between 5 and 25°C, however this range is affected by many variables, therefore a cow can be susceptible to heat stress at temperatures above 20°C.

Animals exhibiting signs of heat stress will become lethargic and inactive and will often stand with heads bowed. They will often pant in an attempt to increase heat loss. Cows suffering heat stress will often move closer together and stand in tightly packed groups.

Cattle will automatically reduce their feed intake during hot weather.  Early lactation cows are most severely affected.  The decreased forage intake alters the composition of the rumen, which can lead to poor health and reduced performance.  If a cow reduces their intake during heat stress, maintaining adequate nutrient intake becomes critical to avoid loss of milk production and it may be necessary to modify the diet and to supplement forage with higher nutrient feeds. 

Ways to prevent heat stress include:
Clean Water*
Ensure there is adequate access to clean water.  If possible, provide additional water sources during hot periods.

Ventilation*
Provide fans and adequate ventilation in holding areas to increase airflow. If all sides of the barn are closed in, it may be practical to remove side paneling to allow the air to flow more easily.  Increasing the roof ventilation is another option.   

Provide Adequate Shade*
Where possible paddock cows in tree lined paddocks to provide natural shade. Provision of mobile sunshades.

Prevent Bunching of Cows
When cows are suffering from heat stress they instinctively bunch together, creating additional stress.

If your herd is suffering with the increased temperatures we are currently experiencing in the UK, DBL can assist with sourcing large volume water troughs, fans and feed supplements. *Some of these items may be available through future FETF Animal Health and Welfare schemes.

For further advice regarding heat stress and assistance with sourcing products to help prevent heat stress please contact Louise Cox on 07943 684215 or e-mail louise@dgblbuyinggroup.co.uk