EFFECTS OF NON-GENETIC FACTORS ON PRE-WEANING GROWTH TRAITS IN DORPER SHEEP MANAGED INTENSIVELY IN CENTRAL MEXICO/Efectos no genéticos sobre características del crecimiento predestete de corderos Dorper manejados intensivamente en el centro de México

The objective of this study was to determine the non-genetic factors which aect growth traits in Dorper lambs under intensive conditions. Nine hundred and ninety birth weight records and 851 weaning weight data from a commercial sheep farm were used. A model containing the eects of year of birth, season of birth, litter size, dams' age and gender was used for identication of factors aecting growth traits. Birth weight was highest (p < 0.05) in summer and lowest in winter and spring. Male lambs excelled females in birth weight, weaning weight, and average daily gain. Young dams produced ospring with a lower (p < 0.05) birth weight and weaning weight than older ewes As a conclusion, important inuences of environmental factors on growth traits were identied for Dorper lambs.