Heat stress: How ER can change the composition of milk

High temperatures are a major challenge for dairy cows. Cows can develop initial heat stress even at temperatures well below 20°C. This not only affects the health and well-being of the animals, but also the quality and composition of the milk. But how exactly does milk change during periods of heat?

1. milk yield decreases due to heat stress

One of the most noticeable effects of heat stress is the reduced feed intake of cows. Less energy intake means that milk production is reduced by 10 to 25 % decreases. The cows can no longer optimally convert the energy they consume into milk.

2. fat content of the milk decreases

Heat stress affects fermentation in the rumen and reduces the production of acetic acid, which is crucial for fat formation. This reduces the fat content of the milk by 0.2 to 0.5 %which has a direct effect on milk quality and processing properties.

3. protein content reduced under heat stress

As the cows have to use more energy for body cooling, less energy is available for protein production. This leads to a protein loss of 0.1 to 0.3 % in the milk in the milk.

4. higher lactose concentration

As the amount of milk decreases, the concentration of lactose contained in the milk increases slightly. This can affect the palatability and technological properties of the milk.

5. cell counts and germ content increase

A weakened immune system and higher temperatures promote bacterial growth in the milk. This leads to:

• Increased somatic cell count (SCC) – an indicator of inflammation in the udder.

• More free fatty acidswhich reduce the shelf life of the milk.

• Higher total bacterial countswhich increases the hygiene requirements for milk production.

This keeps the milk quality stable

Effective measures are needed to minimize the negative effects of heat stress:

• Optimum barn ventilation: Hose ventilation systems such as CAT3000® ensure an even supply of fresh air.

• Shading & water supplyCooling areas and sufficient water help the cows to cool down better.

• Adapt feed managementMore crude fiber and less easily digestible carbohydrates can optimize digestion.

Conclusion: Proactive management ensures milk quality

Heat stress has a serious impact on milk yield and composition. With well thought-out solutions such as hose ventilation, feed optimization and a good water supply, farmers can counteract this and ensure consistently high milk quality.

Would you like to reduce heat stress in your company? Contact us for individual advice on ventilation solutions!