Age characteristics of reproducive and maternal qualities of sheep of the prekos breed

Abstract

The studies were carried out during 2020-2021 on ewes (515 heads) of the Kharkiv intrabreed type of the Prekos breed (KhTP) and their offspring in the conditions of the breeding plant of the State Enterprise of the Experimental Farm Gontarovka of the Institute of Animal Sciencе of the National Academy of Sciences of Ukraine.
 It was established that for 45 days during artificial insemination, the fertility of sheep (OP), calculated according to the results of their lambing, averaged 91.8 %. The highest rate was characterized by sheep that had the third lamb - 97.3 %. According to the results of 4-6 lambs, a relatively stable high fertility of queens was noted - 93.4-95.3 %. Significant downward deviations of this indicator were observed in ewes used for reproduction in the first and second years, and especially in animals with 7 and 8 or more lambing. Analysis of variance found that the age factor of ewes is highly likely (p<0.01) associated with their fertility, and the strength of its influence ŋх 2 is 0.491.
 The factor of individual rams-producers also influences (OP) ewes. The variability due to the influence of this factor varied from 87 to 95.1 %.
 Different (OP) of ewes, due to their age, had a corresponding effect on the indicators of their multiple pregnancy (P), calculated per 100 inseminated heads. This indicator in ewes for the first fifth lamb ranged from 113 to 150 lambs. At the same time, there is a clear trend of its growth due to the increase in the number of reproductive years. However, this trend is not linear and is valid for animals with 1-6 lambs. Ewes with 7 and 8 or more lambs worsen their reproductive ability rather sharply.