Effect of genetic and environmental factors on the phenotype characteristics of lambs

The aim of this study was to determine the influence of environmental factors affecting body weight variability of lambs in two crossbreed groups: Pirot x W?rttemberg and Sjenica x W?rttemberg. Both populations were managed under the same farm conditions. The data were analyzed to determine the effect of age of the dam, weight of dam, birth type, sex, year and season, on the birth weight and weaning weight of crossbreed lambs. Statistical analysis was performed by GLM procedure using the SPSS statistical package program. The average birth weight of Pirot x W?rttemberg lambs was 3.56 kg while Sjenica x W?rttemberg lambs was slightly higher at 3.69 kg. The difference on birth weight between the two crosses was not statistically significant (P>0.05). The average weaning weight of Pirot x W?rttemberg lambs was 23.54 kg while Sjenica x W?rttemberg lambs had higher weight at 24.37 kg. The difference of 0.83 kg on weaning weight was statistically significant (P <0.05). Body weight, depending on the environmental factors, ranged from 3.17 to 3.96 kg at birth and from 22.12 to 24.18 kg at weaning in Pirot x W?rttemberg lambs. Body weight of Sjenica x W?rttemberg lambs ranged from 3.39 to 3.99 kg at birth and from 22.69 to 25.44 kg at weaning. Statistical analysis showed that the differences were statistically significant (P<0.05) and highly significant (P<0.01).