UTICAJ NEGENETSKIH FAKTORA NA MASU JAGNJADI PRI ROĐENJU, SA 30 I 90 DANA STAROSTI KOD SJENIČKE PRAMENKE

Abstract

Overall sheep production is influenced by certain factors, genetic and paragenetic. Fertility traits of sheep are more influenced by non-genetic systematic factors, whether they are discontinuous in nature (year of birth, season of birth and lambing, partus in order, type of birth, sex of lambs) or continuous (age at first insemination, etc.). The research included 180 sheep of the Pramenka breed, Sjenica pramenka in the breeding areas of three municipalities: Priboj, Prijepolje and Nova Varos. Data on the growth of lambs in the lactation period were analyzed, as follows: weight at birth, weight at the age of 30 and 90 days of age. The influence of fixed paragenetic factors such as: breeding area, year of birth of ewes, lambing in order, type of lambing, sex on the manifestation and variability of the observed characteristics of lamb growth in the lactation period was observed. The breeding area and type of birth had a significant effect (P <0.01) on the weight of lambs from all three age categories. The year of birth of lambs and the interaction of the breeding area and type of birth had a highly significant effect (P <0.01) on the mass of lambs at birth and at the age of 90 days, and significantly (P <0.05) on the mass of lambs at 30 days of age. Lambs in a row and a half of lambs did not significantly affect any trait of lamb growth in the lactation period. The coefficients of determination for the observed traits were high and very significant and ranged from 0.775 (77.5%) in the mass of lambs at birth to 0.397 (39.7%) in the mass at 30 days.