The cow breeding sector is evolving continuously in response to the rapid growth in demand for livestock products. Increased environment temperature in summer season affect the overall clinical indicators and displays negative consequences on the production and reproduction of animals. In condition of our country, the greatest impact of heat stress in summer affect in the overall clinical indicators. Animal temperature increase by 0.2 to 0.4 ° C, frequency of breathing increases by 3.2 to 4.3 acts on the respiratory minute and the average value of the pulse increases to 2.4 to 4.1 pulsacione per minute. Under the influence of heat stress in the summer season varying the reproductive indexes. The duration of the oestral cycle is increased by 1.2 to 2.2 days, the time of oestrus decreases by 2 to 5 hours, the percentage of fertilization decreases by 20%, but the average time of the first heat show is not affected (before the service period).