IN VIVO ASSESSMENT OF GROWTH TRAITS AND MEAT PRODUCTION IN CHAROLLAIS AND KENT LAMBS*

The objective of this study was to determine the effect of lambing year, month of lambing, sex of lamb, sire effect, dam’s age effect, and effect of litter size on the indicators of meat production of Charollais and Kent breeds. The evaluation was conducted between the years 2009–2011, when 591 of Charollais and Kent lambs were monitored. The lambing year had a significant effect only on birth weight. Similarly, the month of lambing was manifested in significant birth weight differences. We observed a higher growth intensity in lambs born in spring (March, April). These ram-lambs had greater birth weight, live weight at 100 days of age, average daily gains from birth to 100 days of age, and musculus longisimus lumborum et thoracis (MLLT) depth compared with ewe-lambs. Similarly, a greater fat thickness was measured in ram-lambs. Comparing individual sires, the most significant differences were obvious in birth weight, in MLLT depth, and in fat thickness. On the other hand, the highest growth abilities and the lowest fat thickness were observed in sheep at the age of 4 years. Comparing litter size, the highest attributes were achieved in singles rather than in twins and triplets.