Characteristics of lambs and milk productivity of Tsigay breed ewes and F1 and F2 crosses with Assaf dairy sheep

This article presents data on the growth and development of lambs from birth until weaning, from their mothers of the Tsigay breed, as well as crossbreeds F1 ♀Tsigay X ♂Assaf, F2 ♀ Tsigay 25% X ♂Assaf 75%, and F3 ♀Tsigay 12.5% X ♂Assaf 87.5%. The measurements of udder size, udder volume, milk productivity for twenty days after lambing, fostering and milking periods, and overall lactation were recorded. Additionally, the average daily milk yield, milk composition, fat, and protein content in the milk were analyzed. The average weaning weight of F3 lambs from their mothers was 32.81±0.99 kg, F2 was 29.40±1.78 kg, which is 3.41 kg lower, and F1 was 28.56±1.11 kg, significantly lower (P ≤ 0.01) by 4.25 kg. In the first 20 days after lambing, the milk productivity of F2 ewes was 64.09±7.85 kg, higher compared to F1 ewes by 15.41 kg and by 27.87 kg (P ≤ 0.01) compared to purebred Tsigay ewes. The largest udder volume was found in F2 ewes, measuring 2275.20±257.90 cm3, which is 785 cm3 less than in F1 ewes and 943 cm3 less than in purebred Tsigay ewes. The difference between the two groups is statistically significant (P ≤ 0.05). Over 208 days of lactation, crossbred F2 ewes produced 268.38±33.67 kg of milk, which is 62 kg more than F1 ewes, who produced 206.00±26.86 kg in 207 days, and 126 kg more than purebred Țigay ewes, who produced 141.72±13.83 kg in 198 days. The difference is statistically significant (P ≤ 0.01). Regarding the chemical composition, there were slight differences between purebred Tsigay ewes and F1 ♀Tsigay X ♂Assaf crossbreeds, while the fat and protein percentages were the same (9.03 and 8.91, respectively). In F2 ♀ Tsigaiy25% X ♂Assaf 75%, fat, protein, and fat +protein content was higher.