Effect of heat stress on the reproductive capacity of dairy cows and the method for its improvement
DOI:
https://doi.org/10.25930/2687-1254/007.2.15.2022Keywords:
beef cattle breeding, breed, Aberdeen Angus, servicing bulls, first-calf heifers, reproductive organs, reproductive qualities, scrotal size, calf crop, sexual dimorphismAbstract
High ambient temperature leads to heat stress in dairy cattle. First of all, the negative impact on the body of cows is manifested by a decrease in reproductive function.
The efficiency of insemination decreases. The duration of the service period increases. The ovaries of animals are reduced in size. They have firm consistency. There are no follicles. Such clinical signs indicate hypovarianism.
The article presents data on the incidence rate of hypovarianism of Black Pied cows of the SEC collective farm “Pole Star” in the Kochubeyevsky District of the Stavropol Territory during the summer grazing period. It was found that the incidence rate of cows from May to October ranged from 17.0% to 40.6%. The highest incidence rate – 37.2% and 40.6% was observed in July and August, when the maximum air temperature during the daytime reached
+34 -+36°С. The least spreading of hypovarianism in experimental animals was in May and September, when the temperature did not exceed +24°C – 17.0% and 21.1%, respectively. In order to determine the effectiveness of the medicine Iodinol for the treatment of hypovarianism, a control and experimental groups of animals were formed. There were 14 head in each group. The treatment was not carried out in the control group. As for the experimental group, the medicine Iodinol was used at a dose of 5 ml, intramuscularly, three times, with an interval of 10 days. It was found that the use of the medicine Iodinol allows to regenerate the capacity of the ovaries in 92.8% of Black Pied cows and successfully inseminate 78.5% of the animals. The insemination index in experimental animals was 1.36 versus 1.75 in the control.
