Top tips to minimise risks of heat stress in dairy herds

With temperatures tipping the scales at well over 30°C in parts of the UK recently, dairy farmers are being warned of the high risk of heat stress in cattle, with potential for a significant impact on performance and fertility.

“While we have seen extremes in the last week, cattle can be affected by heat stress at far lower temperatures than those recently experienced,” explains KW ruminant technical manager, Charlotte Ward.

“Crucially, fertility can be affected well before cows show any behaviour of heat stress, or before production is impacted.”

Charlotte advises to take precautionary steps to minimise the risks, preparing five ‘top tips’ to help guide the dairy farmer.

• Provide adequate drinking water

At least 15 per cent of the herd should be able to drink at the same time, so allow for adequate trough space. Also, check refresh rates and watch cows in the afternoon when water points are under pressure. Cows drink between 60-120 litres per cow, per day, so provide fresh, clean water to encourage intakes.

• Apply careful herd management

Reduce stocking density where possible and make sure shading is available for grazing animals. Consider grazing at night.

• Adopt building management procedures

Opening vents or shed sides can improve ventilation, being sure to clear away anything blocking airflow. Carefully consider the placement of fans.

• Adjust feed management

Mix rations just before feeding out, so feed is always fresh. Adjust volumes if required and clear away refusals. For housed cows, feed 60% of the ration between 8pm and 8am.

• Change ration formulations

Dry matter intake is reduced in periods of heat stress, so to maintain the cow’s nutrient intake, the nutrient density of the diet needs to be increased, and the ration made as palatable as possible.

KW advises feeding high quality forages or high energy forage replacers, and to feed a greater ratio of concentrates to forage, as part of a carefully planned ration formulation.

“Forage produces seven times more heat than concentrates,” explains Charlotte, “but ensure a good quality digestible fibre source such as sugar beet feed or soya hulls is fed to maintain rumen health.

“Your nutritionist can advise on the best ways of achieving the desired ration formulation and getting best results. For example, introducing liquid or moist feeds such as brewers grains as a forage replacer, will also improve palatability, drive intakes and reduce sorting.”