Some Biological Characteristics and Prediction of Sheep Productivity at Different Variants of Breed Selection

摘要

The paper presents the findings on the morpho structural diversity of sheep placenta, depending on such factors as age, exterior and physique characteristics, breeds, ewes prolificacy that are fundamental in assessing progeny viability. The experiment involved the ewes of the Caucasian and North Caucasian meet-and-wool breeds inseminated by the rams of the same breeds as well as the Texel, Poll Dorset, Edilbay and their progeny. The biomaterial for the research was the placenta and blood of the experimental animals. Ewes aged 2.5 and 3.5 years had the lightest placenta – 165 and 172 gr, ewes aged 4.5 and 5.5 years had the heaviest placenta – 230 and 247 gr. It has been also determined that the most favourable age for gestation in ewes is 4.5-5.5 years. Interrelation of the placenta morphostructural parameters (placenta weight, the number and size of cotyledons) and the lambs live weight and productivity has been established. This allows us to view placenta as a bioscopic material for assessing and prediction of future sheep productivity at early age.