Influence of individual paratype factors on the variability of the development of lambs in postnatal ontogenesis

Abstract

Goal. To study the influence of the number of lambs in the offspring and the age of the mothers on the absolute indicators and variability of their live weight and growth intensity in the early postnatal ontogenesis. Methods. The research was carried out on lambs at birth and after they reached 120 days of age using generally accepted methodological provisions and methods of biometrics and statistics in animal husbandry. Results. The regularity of the variability of the live weight of lambs determined by the type of birth was established: with an increase in the number of individuals in the offspring, its indicators decrease. Singles showed the highest variability — 15.0%; in twins, it decreased to 13.8%, and in triplets — to 11.9%. A sufficiently high probable influence of the factor of mothers’ age on the variability of this trait in lambs born as singletons and twins was established. An increase in the number of lambs raised by a mother ewe from one to three leads to a decrease in their live weight at 120 days of age by 9–10%. Variability indicators compared to the previous period are growing almost twice. At the same time, the pattern of variability related to the increase in the number of lambs in the offspring remains similar to the previous age. Regardless of the age of the mothers, a general feature of the variability of the index of average daily weight gain of lambs is a significant advantage of twins over singles. Conclusions. The type of birth of the lambs, as well as the age of their mothers, likely influences the parameters of the homogeneity of the population based on the live weight of the young animals at birth and 120 days of age. At the same time, the variability tends to decrease with the increase in the number of lambs born and raised by the ewe. Indicators of the average daily growth of lambs are marked by significant variability, although its parameters are higher in twins. More homogeneous young animals according to the investigated characteristics can be obtained from ewes whose growth has already been completed, that is, from 4–6 years old animals.