Characteristics of F1 crossbreeds obtained from crossing different sheep breeds in the Republic of Tuva

The aim of the study is to investigate the growth and development, wool productivity of crossbreeds obtained by crossing stud rams of the GornoAltai breed with ewes of the Tuvan shortfattailed breed. The studies were conducted in the Republic of Tuva in 2023–2024. For the comparative study, two groups were created: crossbreed GornoAltaiTuvan (experimental group, n = 18) and purebred young animals of the Tuvan shortfattailed breed (control group, n = 18). The dynamics of live weight from birth to 12 months (absolute, average daily and relative gains) were studied. The exterior parameters, constitution indices, length and fineness of wool fibers were determined. Statistical processing was carried out using the Snedecor V4, MS Excel programs. The crossbred lambs had a high live weight at birth of 5.16 kg, which is 1.2 times (P ≥ 0.999) more than that of their purebred peers. By 6 months, the crossbred lambs weighed 37.48 kg, which is 1.14 times more than that of purebred lambs (P ≥ 0.95). At 12 months, the crossbreds with a live weight of 40.71 kg exceeded the purebred lambs by 1.09 times (P ≥ 0.95). The relative increase from birth to 6 months is 1.05 times (P ≥ 0.95) higher in purebred young animals compared to crossbreds. The advantage of crossbred sheep over purebred ones in terms of measurements and body conformation indices at 6 months was: by hip width – by 1.37 times (P ≥ 0.99), chest girth – by 1.04 (P ≥ 0.95) and metacarpal girth – by 1.10 times (P ≥ 0.999); by the massiveness index – by 12.3 abs.% (P ≥ 0.95) and bone content by 2.0 abs.% (P ≥ 0.99). At 12 months. The superiority was noted in crossbred sheep in terms of height at the withers by 1.04 times (P > 0.99), chest depth by 1.09 (P ≥ 0.999), chest width by 1.12 (P ≥ 0.95), hip width by 1.19 (P ≥ 0.999) and chest girth by 1.14 times (P ≥ 0.999); in terms of massiveness indices – by 13 abs.% (P ≥ 0.95) and compactness – by 17.22 abs.% (P ≥ 0.95). The wool length and down fineness of the crossbred sheep exceeded the indicators of purebred sheep by 1.22 (P ≥ 0.999) and 1.11 times (P ≥ 0.999), respectively. Crossbreeding had a positive effect, since the fineness of down fibers in crossbred animals is close to the standard of the GornoAltai breed. The conducted crossbreeding significantly improved the productive indicators of sheep.