Özet:

In the summer months, low pregnancy rates are observed in milk cows applied to artificial seed due to heat stress. The aim of the presented study is to determine the achievement of a higher rate of pregnancy from some synchronization methods in cows exposed to heat stress. The study material was made by 112 Holstein-Friesian breeds, who had a small birth in a milk cattle plant in the province of Shanlıurfa, ranging from 3 to 7 years of age. There were no measures taken against heat stress in the business. Working groups to apply ovulation synchronization protocols to be included in Group I (Ovysnch method), II (Cosynch method) and III (Ovysnch + progesterone method) cows were randomly selected in 30 pieces in each group and artificial seeding was applied within the protocol. The cows, which belong to the control group Group IV, were selected from the observed cows (n=22) without any synchronization method during the period of the study, and the artificial seed process was applied on the day they showed estrogen. The study was carried out in the province of Sanlıurfa, where the temperature moisture index was calculated in July-August, it was seen that there was a serious heat stress from the point of view of milk cattle. The difference was significant for the observation of symptoms of estrus in the first three groups where ovulation synchronization methods were used (36.67% in Group I, 16.67% in Group II and 40% in Group III) (p<0.001). After the 30th. Daily transrectal ultrasound pregnancy tests found that there was no difference in pregnancy rates between groups (23,33,20,26,67 and22,73) (p>0.05). As a result, milk livestock in Sanlıurfa and its surroundings were seen to be exposed to severe heat stress in the summer, and the hypothesis was made that the methods of ovulation synchronization in heat stress can be used to obtain reproductive efficiency.

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