British dairy farms missing out on milk production by failing to address heat stress

Dairy farmers could be losing milk production worth tens of thousands of pounds by failing to protect their cows from heat stress during the summer.

That was the message from independent vet consultant, Dr Tom Chamberlain from Chalcombe Ltd, at a Lallemand Animal Nutrition workshop at Total Dairy in Stratford-uponAvon.

A live poll run during the workshop indicated that 92% of farmers have seen heat stress on their farm and 86% thought they’d lost more than 50 litres/ cow during lactation as a result of this, with many suggesting they’d lost more than 150 litres/ cow.

To reiterate the impacts of heat stress, during the workshop Dr Chamberlain shared results of a study, carried out in conjunction with Lallemand, to assess whether heat stress is a problem in British dairy herds.

The study focused on nine farms in England in the summer of 2022 – from Cheshire in the north to Devon in the south – and temperature and humidity were measured inside cattle sheds and out at grazing.

“The study shows the amount of time cows suffered from heat stress during the trial period, which ran from April to October, was 57% for cows kept inside, and 22% for those out at grass,” said Dr Chamberlain.

He said the study suggests the average housed cow lost 139 litres of milk production due to heat stress during the summer, while the average cow out at grass missed out on 129 litres of production.

“Across those nine farms, the average loss of production from heat loss is £128 per cow, with herd losses ranging from £24,000 to £90,000,” added Dr Chamberlain.

He encouraged farmers to draw up a heat stress management plan for summer 2023 and suggested adopting a siesta management approach.

“This involves getting the cows in at 10am and keeping them in until after milking, before turning them out again at 4pm,” said Dr Chamberlain