6 heat stress management tips for dairy farmers

Minimising the impacts of heat stress should be at the front of dairy farmers’ minds as highs above 30C and in-shed night-time temperatures of above 20C become commonplace.

This is according to Wynnstay dairy specialist Beth Parry, who says extreme heatwaves have been common this year, and should prompt action.

Mrs Parry’s advice comes during an amber warning of extreme heat issued by the Met Office for most of the southern half of the UK, which lasts until the end of Sunday.

See also: Water abstraction ban a ‘devastating blow’ for Fife veg growers

“As a result of the high temperatures in the day and staying overnight, cows will struggle and performance and fertility may be affected,” she says.

“When the 24-hour daily average temperature humidity index is 65 or more (achieved when hitting only 21C and 60% humidity), then conception rates, days open and anestrus will be impacted.

“This can affect not only cows being served on the day, but also those served up to three weeks ago, and those to be served in the next three weeks.”

Met Office predictions suggest extreme weather events may become the norm, says Mrs Parry. Ventilation and fans are long-term solutions that require investment, but will bring major benefits.

Management techniques to try now

Mrs Parry suggests six management techniques that farms can start doing straight away which will help through warm weather spells.

  1. Limit standing times: Working with smaller groups of cows at milking can limit standing time, help parlour cow flow and help competition with feed and water in the shed after milking
  2. Watch manure consistency: Heat stress leads to loose muck and lost nutrients caused by decreased gut motility and rumen fermentation. Ask your nutritionist about reformulating rations in case dry matter intake drops
  3. Check troughs and water flow and natural sources of water: Cows need 90-150 litres on a normal day, so in extreme heat they need plenty of clean water. Monitor any natural sources, as lack of rain is affecting water levels
  4. Supplementation can help yield loss: Seek advice on a sodium source, such as rock salt, and potassium supplementation, to counter some yield losses. Molasses is high in potassium, which is lost in the greatest amounts through sweat and saliva in heat-stressed cows
  5. Ensure dry matter intakes are maintained: Make a conscious effort to drive dry matter. This may involve molasses, which has been shown to produce a greater amount of butyrate in the rumen. Butyrate is the volatile fatty acid responsible for gut tissue growth, promoting a healthier and more efficient rumen
  6. Offer a buffer feed during cooler times of the day: Feeding a buffer in the early morning and late evening can help alleviate issues with yield drops. However, watch fibre levels as higher-fibre feed will take longer to digest in the rumen and the cow will produce more heat as a result.