Genoveva Staykova1, Margarit Iliev2 and Todor Tsonev3
1 Agricultural Academy, Agricultural Institute – Shumen, 9700 Shumen, Bulgaria
2 Agricultural Academy, Institute of Agriculture – Karnobat, 8400 Karnobat, Bulgaria
3 Agricultural Academy, Research center for Agriculture – Targovishte, 7700 Targovishte, Bulgaria
Staykova, G., Iliev, M. & Tsonev, T. (2025). Effect of different sources of specific variance on the weight development of sheep from The North East Bulgarian merino breed. Bulg. J. Agric. Sci., 31(5), 1032–1038
This research aims to determine the effect of different sources of specific variance on the weight development of sheep from the North East Bulgarian Fine Fleece breed (NBFF) – Shumen type. The subjects of the study were 820 sheep, born between 2013 and 2020 and raised at the Scientific Center for Agriculture in Targovishte. The following traits were analyzed: live weight at weaning (90 days), at 9 months, and 1.5 years. Average daily gain from weaning to 9 months and from 9 months to 1.5 years was calculated. The influence of the factors—year of birth, type of mating, and breeding line — was researched. An analysis of variance was performed using a multivariate linear statistical model for each age group studied. It has been established that the year of birth has a highly significant influence on the live weight and the average daily gain at all ages and periods studied in sheep from the North-East Bulgarian Fine Fleece breed (NBFF) – Shumen type. The type of mating had a significant influence on the live weight at weaning and on the average daily gain from 9 months to 1.5 years. Linear affiliation had a substantial effect on the average daily gain from 9 months to 18 months. It has been established that the average live weight of sheep from the North-East Bulgarian Fine Fleece breed (NBFF) – Shumen type at weaning was 28.751 kg, at 9 months – 42.033 kg, and at 18 months was 53.617 kg. The average daily gain from weaning to 9 months was 0.074 kg and from 9 months to 1.5 years was 0.045 kg.