Influence of birth type on body weight of lambs from birth to weaning in various strains of sheep pramenka

The dynamics of increasing of bodyweight of lambs is conditioned by genetic factors, environmental factors and their interaction. The aim of this work was study variability of bodyweight of lambs related to type of birth of lambs in sheep genotype of four different strains of pramenka type and four growth stage: at the birth time, at the 30, 60 and 90 days of age after birth. For this investigation used lambs of four strains (Svrljiski, Pirotski, Sjeni?ki, Sarplaninski) of sheep type Pramenka (450 lambs per strain) for study dinamics of bodyweight at the time of birth, 30, 60 and 90 days after birth during three years of experiment (2011-2013). The results showed that the bodyweight of lambs born singles was higher than bodyweight of lambs born twins in studied four sheep genotypes i.e. Pirotski (4.00 kg : 3.40 kg), Svrljiski (3.90 kg : 3.79 kg), Sjeni?ki (3.73 kg : 3.61 kg), Sarplaninski (3.81 kg : 3.74 kg). The differences of bodyweight between lambs born singles and twins was significant for genotypes Pirot pramenka and Svrljig pramenka, on the level of significance for Sjenica pramenka and was not significant in Sarplanina pramenka. At the age of 30 days, the influence of birth type on the bodyweight of lambs was not statistically significant in any of the examined strains. The difference of bodyweight between singles and twins was statistically significant at the 60 days old of lambs in Svrljig pramenka and in lambs at 90 days old of Svrljig pramenka. On the base of results is established that type of born associated with significant differences of bodyweight at the birht time expressed later at the 60 and 90 day old lambs.