Abstract
This paper presents a comprehensive and detailed study of the growth, live weight dynamics, body conformation traits, and zootechnical indicators of lambs born from Kazakh coarse-wool fat-tailed sheep (KG) and Kazakh fat-tailed semi-fine wool sheep (KPG) during the period from birth until they are weaned from their dams (4–4.5 months). The research was conducted at the “AkBas-Pavlodar” LLP farm in Pavlodar District, Pavlodar Region, at the “Ardak” and “Birlik” farms in Akkuly District, Pavlodar Region, and at the “Bepen” farm in Beskaragay District, Abai Region. During the study, the lambs’ live weight, absolute and average daily weight gains, body measurements, and key indices were carefully and systematically analyzed, with consideration of environmental conditions and feed quality. The methodology of the study was aimed at monitoring growth dynamics according to the lambs’ age, as well as evaluating their body structure, limb development, chest capacity, and skeletal growth. Analyzing live weight gain from birth to four months is particularly important in sheep breeding because this period is characterized by the most intensive growth, the establishment of future productivity, and high sensitivity to feeding, management practices, and environmental factors. The results showed that the growth rate and live weight of lambs were directly influenced by breed characteristics, sex, milk yield of the dams, and feeding quality, with pronounced sexual dimorphism observed. Lambs of Kazakh coarse-wool fat-tailed sheep had compact bodies, proportionally developed limbs, and well-formed chest cavities, whereas lambs of Kazakh fat-tailed semi-fine wool sheep had elongated bodies, strong limbs, and well-developed skeletons. Moreover, by 4–4.5 months of age, all lambs exhibited uniform body traits that fully met zootechnical standards for meat and fat productivity, making these characteristics important for further rearing, scientific evaluation, and production-oriented planning.