Influence of genotype and castration of rams on consumption and use of feed ration nutrients energy

The aim of the study is to assess the characteristics of energy consumption and digestibility by pure-bred and crossbred rams and wethers. Objectives: to establish the volumes of intake and the digestibility coefficient of gross energy of nutrients by young sheep of different genotypes, to determine the nature of the use of metabolic energy for maintenance, super-maintenance, product synthesis and the coefficient of its useful use. The scientific and economic experiment was conducted in 2020–2022 at OOO Kolos, Oren-burg Region. The object of the study is 4 groups (n = 15) of young sheep: I – purebred rams of the Tsigai breed; II – crossbred rams (½ Tsigai × ½ Edilbaev); III – purebred wethers of the Tsigai breed and IV – crossbred wethers (½ Tsigai × ½ Edilbaev). Crossbred rams (½ Tsigai × ½ Edilbaev) and wethers-analogues of the same genotype by origin exceeded purebred rams and wethers of the Tsigai breed in terms of gross energy consumption by 4.41 (P < 0.01) and 4.20 mJ (P < 0.01), respectively, in the level of digestibility – by 3.02 (P < 0.01) and 4.90 mJ (P < 0.01), in the value of the digestibility coefficient – by 0.80 and 1.30 %. Similar intergroup differences were noted in the level of digestible and exchangeable energy. At the same time, the crossbreeds surpassed their purebred peers in the value of the coefficient of digestibility of gross energy by 0.80 and 1.30 %, its productive use – by 5.23 and 5.72 %, and the produc-tive use of exchange energy – by 0.61 and 0.38 %. Wethers of groups III and IV were inferior to their ram analogues of groups I and II by origin in the value of consumed energy of nutrients and used it less effec-tively in metabolic processes.