Heat Stress in Cattle - Full newsletter here

The temperature comfort zone or 'thermoneutral zone' for a cow ranges from -15°C to +25°C. Outside this range, cows have to use coping mechanisms to maintain a stable core temperature. It's not all just about temperature though, when the humidity is high cows will suffer a lot more from heat stress. Check out the full newsletter to see the effect of humidity on temperature at which cows suffer from heat stress. When the humidity is high, cows can become heat stressed at temperatures as low as 22°C. 

Clinical signs of heat stress include:

- Increased respiratory rate and effort.

In more severe cases open mouth breathing can be observed with extended head, potentially with the tongue protruding

- Profuse salivation

- Wider stance to increase lung volume

- Increased heart rate

- High rectal temperatures

- Diarrhoea

- Huddling

- Death

Aside from the above, feed intake will be decreased when cows experience heat stress. Fertility is negatively affected and milk production drops. It doesn't only affect a cow's milk production, but it is also found that the offspring of cows that have experienced heat stress late in their pregnancy will have a reduced milk yield and overall a shorter life span.

Heat stress can also lead to cows standing more, which may result in increased feet problems.