THE INFLUENCE OF PARAGENETIC FACTORS ON LAMB BIRTH WEIGHT AND PRE-WEANING GROWTH IN SJENIČKA PRAMENKA

Abstract

The investigation of the influence of paragenetic factors (farm, year of birth of the ewes, birth order, type of lambing, sex, as well as the interaction between farm and year of birth and between farm and birth order) on lamb body weight at birth and at 30 and 90 days of age was conducted on 268 ewes of the Sjenička Pramenka breed distributed across three farms in the municipality of Gornji Milanovac, born in the period from 2015 to 2023. The study of lamb growth during the suckling period (birth weight and body weight at 30 and 90 days of age) was carried out on a total of 1,399 lambs. Farm, type of lambing, sex of lambs, the interaction between farm and year of birth, as well as the interaction between farm and birth order had a highly significant effect (P<0.01) on lamb body weight at birth and at 30 and 90 days of age. Year of birth had a highly significant effect (P<0.01) only on lamb body weight at 30 days of age, while birth order had no significant effect (P>0.05) on birth weight, but had a highly significant effect (P<0.01) on body weight at 30 and 90 days of age. The coefficients of determination were highly significant (R<0.01), amounting to 0.273 (27.3%) for birth weight, 0.400 (40.0%) for body weight at 30 days of age, and 0.127 (12.7%) for body weight at 90 days of age.