Harm of Heat stress response in Dairy cows

High temperature and heat in summer, when raising dairy cows, a little improper management will cause mature heat stress of dairy cows. Heat stress does great harm to dairy cows. If it is not dealt with in time, it will cause great losses for farmers. There are also many friends who do not understand what this heat stress does. Don't worry, let's have a look at the pro-agricultural network.

What is dairy cow heat stress?

Heat stress refers to the sum of the non-specific responses of dairy cows to the thermal environment in the high temperature environment. The purpose of heat stress is to mobilize the body defense function to overcome the adverse effects in the high temperature environment and maintain the stability of the body. The cow's normal body temperature is about 38.5 degrees, and the suitable feeding temperature is between 10 and 20 degrees. In this temperature environment, it does not need to consume the body's energy to regulate the body temperature, and its milk yield is the best. If the feeding environment is more than 25 degrees, it will consume energy to regulate body temperature, resulting in heat stress. If it is in a high humidity environment, heat stress will occur at about 23 degrees.

Harm of Heat stress in Dairy cows

1. Affect food intake

The suitable growth temperature of dairy cow is 4-20 degrees. The high temperature causes heat stress reaction, which leads to accelerated body temperature, respiration and heartbeat, increased metabolism and endocrine disorders, which will lead to a serious decrease in feed intake and affect milk production. When the temperature of the suitable environment reaches 27 degrees, the feed intake begins to decline; when the temperature is higher than 30 degrees, the feed intake of dairy cows decreases seriously; when the temperature reaches 40 degrees, the feed intake of dairy cows is 20% of the usual or no food intake.

2. Affect milk yield and milk composition.

Heat stress reaction will also lead to the decline of milk yield, the continuous rise of temperature, and the milk protein content of dairy cows is also decreasing. When the temperature increases by 10 degrees, the amount of protein synthesis decreases 0.1kg. When the humidity is higher than 70%, for every 10 degrees increase, the milk yield of the cow will be reduced by 2kg, and its milk protein content will be greatly reduced, affecting the quality of the milk.

3. Affect the fecundity

In the heat stress response caused by high temperature, the cow will mobilize everything in the body to regulate the body temperature and heat dissipation, its metabolism and blood circulation on the body surface will continue to increase, while the blood circulation of the internal organs of the body will continue to weaken, resulting in its nutrition will not be supplied, affecting the reproductive ability. according to data, the conception rate in summer is only 50% and 60% of that in spring and autumn.

4. Affect the resistance

Heat stress reaction will affect the body resistance of dairy cows, easy to cause disease, and summer is the fastest season for bacteria and microorganisms to reproduce. If the environmental hygiene of the enclosure is poor, dairy cows are easily infected with mastitis, uterine inflammation and other inflammation. The incidence of placenta retention in dairy cows is also higher than that in winter, and it is easy to cause abortion and stillbirth in dairy cows.

The above is the harm of heat stress reaction of dairy cows brought by pro-agricultural network. This is the end of the introduction about the harm of heat stress reaction to dairy cows. If you want to know more, please pay attention to pro-agricultural network.