Selection and Genetic Parameters for Productive Performance of Sheep (Ovis Aries) of Trans-Baikal Breed of the Khangil Type

The research study was conducted to estimate the selection and genetic parameters for productive performance of the Trans-Baikal Khangil (TBKhT) fine wool sheep to improve selection efficiency. The relationships between the selecting traits (live weight and wool clip) and the body conformational and constitutional characteristics were revealed with correlation and regression analysis. Among the estimating parameter set, the greatest variability in the animal body mass (11.9–19.4%), wool yield (9.9–11.1%), and horizontal linear body measurements (8.2–12.4%) were observed. With respect to the body conformation indices, the rams were different from the ewes in their greater leg-length, better-developed chest, and stronger bone structure, while a broad longer body with a better-developed posterior part was typical of the ewes. The rams’ live weight and wool yield values correlated with the linear body measurements higher than that in the ewes. It was revealed that the live weight and the chest girth were stronger correlated in both rams and ewes (±0.916, p < 0.001 and ±0.740, p < 0.001, respectively), while the wool yield correlated more significantly with the chest depth in rams (±0.737, p < 0.001) and the distance between tuber coxae bones in ewes (±0.469, p < 0.001). The use of the distance between tuber coxae bones, longer by 1 cm, may predict the TBKhT ram live weight increase by 5.50 kg (r = 0.839; p < 0.001). In ewes, it is indicated that live weight tends to increase by 1.04 kg as chest girth increases by 1 cm (r = 0.740; p < 0.001). The analysis of the pairwise regression equations can indicate that the TBKhT sheep live weight variable is most dependent on the chest girth linear measurement, by 83.9 and 54.7% for rams and ewes, respectively, while the values for the other factor effects comprise 16.1 and 45.3%, respectively. In addition, the multifactor regression model results indicate that the effects of the linear measurement system can explain 94.3 and 74.7% changes in body mass, while the other factors affect the rest of proportion.