Swipe to the left

Heat Stress - The New Normal?

Print
Heat Stress - The New Normal?
By Wynnstay Dairy Team 9 days ago

How molasses in your buffer feed can help!

The last few years have produced some challenging weather conditions for UK dairy farmers, with predictions suggesting extreme weather events may become more common place.With summer approaching, Wynnstay and QLF look at how molasses can help reduce your heat stress losses.

Cows suff ering from heat stress often see a drop in milk production and quality, linked to the cow’s innate instinct to utilise her glucose reserves to reduce her core body temperature through panting, saliva and sweating, thus excreting vital electrolytes required for health. These reserves would otherwise be partitioned for maintenance, production and fertility.

Early signs of heat stress will often include cows huddling around shady or breezy areas, with an unwillingness to lie down. This reduction in grazing and rumination time inevitably leads to a reduction in feed intake and, when associated with increased water intake filling the rumen, results in overall dry matter intake dropping. Problems can start to show in the herd from temperatures of 24˚C and can be exasperated if management changes are not put in place to reduce the challenge.

The effect of humidity on heat stress

Housing cows during the heat of the day and allowing access to grazing at night is growing in popularity, however attention needs to be given to the potential of rising humidity within the housing. Lactating cows producing heat in an enclosed and potentially damp environment without adequate air movement, might result in increased signs of stress including greater sweat production, increasing the risk of vital electrolytes such as potassium and sodium evaporating from, and acidifying the body.

Molasses – an overlooked asset!

As previously noted, the more sedentary heat stressed cow will have a reduced dry matter intake. Offering a buff er feed during the cooler morning and evening periods can help to alleviate the problem, however higher fibre buffers such as hay or older silage take longer to digest in the rumen, and the cow will produce more heat as a result. A higher quality forage is recommended, however, supplementing a QLF molasses product to any buffer will improve fibre digestibility and stimulate dry matter intakes.Center text

Maximising the intakes and digestibility of the forage with molasses, will benefit milk quality/butterfat levels. Molasses has also been shown to produce a greater amount of butyrate in the rumen, the fatty acid responsible for gut tissue growth, thus promoting a healthier and more efficient rumen.

Further to this, molasses-based products are naturally high in potassium, the electrolyte lost in the greatest amounts through the increased sweat and saliva production of heat stressed cows. Research has shown that supplementation with potassium can counter some of the yield losses experienced through heat stress, particularly if a sodium source, such as rock salt is also provided.

  • Consider humidity when housing cows in hot conditions; utilise fans in collecting yards and sheds
  • Buffer feed cows at cooler times
  • Include QLF molasses and rock salt to alleviate production losses


Temperature Humindity Index (THI) Relative Humidity (%)


Written by Bronwen Pihlwret - Regional Sales Manager with QLF UK