﻿ Regulation technology of heat stress by YeaVita R in dairy cows - Animal nutrition - Angel Yeast


Regulation technology of heat stress by YeaVita R in dairy cows

March 19th, 2019

By Xiao Xiangqian, Angel Animal Nutrition, China

Dairy cow heat stress refers to a state in which the cow can not release excess heat from the body when it is stimulated by excessive high temperature which exceeds its ability to regulate body temperature, so that it can not maintain normal body temperature。 Holstein dairy cows are characterized by large size, poor heat dissipation area per unit body weight, better cold resistance of body hair and tissues, poor sweat excretion ability and poor heat dissipation ability of body surface, which lead to their cold and heat resistance and extremely sensitive to high temperature in summer。 The ideal ambient temperature of dairy cows is - 0。5 - 21 ℃, and the optimum ambient temperature of lactating cows is 5 - 25℃。 When heat stress is stimulated, dairy cows show a series of physiological reactions, i。e。 heat stress syndrome, mainly including heat asthma, heart rate acceleration, membrane system damage, thyroid and adrenal function enhancement, slow oxidation metabolism in vivo, increase of peroxides, slow metabolism of substances, decrease of immunity, disturbance of water and electrolyte balance, increase of urination, increase of ion loss and so on。 The decrease of feed intake, milk production, milk quality, reproductive performance and a series of diseases induced by adult cows have reduced the economic benefits of farming。

Judgment of heat stress in dairy cows

Heat stress in dairy cows is caused by many external and internal factors. Therefore, the evaluation of heat stress in dairy cows is mainly based on external environmental factors (THI), combined with physiological (respiratory rate, rectal temperature, heart rate, pulse), biochemical indicators (heat stress protein, cortisol, thyroxine, etc.). In actual production, THI is used as an important index to determine whether cows are under heat stress in summer, especially as an important index to evaluate the effects of heat stress on production performance, physiological and biochemical indicators of dairy cows. For dairy cows, THI > 68 means heat stress.When THI reached 68, cows breathed more than 60 times per minute, rectal temperature exceeded 38.5 C, and began to lose milk.When THI reached 70, the respiratory rate exceeded 70 breaths per minute and the rectal temperature exceeded 39 C, which was characterized by mild heat stress。When THI reached 80, the respiratory rate exceeded 85 breaths per minute, rectal temperature exceeded 40 C, showing moderate heat stress.When THI reached 90, the respiratory rate was 120-140 breaths per minute, rectal temperature exceeded 41 C, which was characterized by severe heat stress。

Technical measures of dairy cow heat stress regulation

Physical environmental regulation technology

1. Reducing solar radiation


Reducing solar radiation

2. Cooling system


Cooling system1

Cooling system2

Technical Measures of Feeding Management

1。 It is advisable to control the feeding density of the herd。 The area occupied by each adult cow in the cowshed is about 5 m2, and the area occupied by each adult cow in the sports ground is 15-20 m2。

2。 Increase feeding times, prolong feeding time, avoid noon, try to arrange more feeding in the morning and evening, less feeding at noon。

3。 According to the local climate change characteristics, avoid milking during the peak temperature period。



Technical Measures of Feeding Management

Technical Measures of Nutrition Regulation

1. Provide adequate and clean drinking water.


2. Increase the ratio of fineness to roughness.

The proportion of concentrate can be increased appropriately under heat stress, but it should not exceed 60%。 Provide high quality, palatable green juicy feed, such as alfalfa, ryegrass, etc。 During the period of heat stress, dietary CF content was about 17%, NDF content was 25%-28%, ADF content was 18%-19%。 Excessive fiber content reduces feed intake and low fiber content affects rumen fermentation of dairy cows and reduces feed utilization rate。 TMR feeding technology can be used in production to achieve a balanced supply of concentrate and roughage。

3. Increase the energy level in the diet.


4. Increase the protein level in the diet.


5. Increase the level of minerals in the diet.


6. Increase the level of vitamins in the diet.

Because of the decrease of intake during heat stress, the vitamin concentration should be increased accordingly。 Especially the content of VA and VE can be 3-5 times of the constant, and the content of VC can be increased to 0。04%-0。06% of the dairy cow diet。

7. Use anti-stress products.



About Angel Animal Nutrition:

Fubon is a brand of Angel Animal Nutrition。 Fubon is committed to developing natural, efficient microbial feed derived from yeast with Angel's leading technology in yeast industry, providing the best service solutions for the nutrition and health in animals。 Angel Animal Nutrition creates value for global feed and animal agriculture customers through continuously upgraded products and professional services。

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