Heat stress in dairy cows can occur when temperatures go over 24°C and relative humidity is above 80%.
These conditions are likely to be present in the early days of this week and follow on from very warm weather on Saturday and Sunday.
Moderate heat stress is likely when temperatures go above 24°C, with more severe heat stress when temperatures go above 26°C.
Essentially, heat stress is when the cow needs to work harder to cool down.
The hotter the temperature, the harder she needs to work and the more energy she will have to partition to cooling rather than production.
The most important thing over the next few days is to make sure cows have enough fresh and clean water.
High water intake
Water intake will be exceptionally high during this period and you will see cows gathering around the water troughs.
Shade is also important, particularly at the warmest parts of the day.
However, where animals are grouped together tightly, then the ambient temperature can increase.
It could be wise to delay evening milking by a few hours which may be beneficial for the cow and the milker
This is important to keep in mind where cows are waiting to be milked in the collecting yard.
It could be wise to delay evening milking by a few hours, which may be beneficial for the cow and the milker.
Ambient temperature is an important consideration for farmers who keep cows indoors.
While outside temperatures may be in the mid-20s, the temperature in the shed could be closer to 30°C and a high relative humidity due to poor ventilation.
Increasing ventilation in the shed should be considered before mechanical ventilation will be required.
The signs of heat stress include panting and a drop in milk yield and reduced rumination, which could lead to acidosis, particularly where a lot of concentrates are being fed.
Feeding high-quality, highly digestible grass will help to reduce heat stress, as the feed will be digested quicker and with less energy and heat generated.
If bulls are still with cows, it would be sensible to use AI alongside bulls, as bull fertility and semen quality can drop in warm weather.