Biological fertility and milk yield in Bulgarian Dairy Synthetic Population sheep according to breeding line

N. Stancheva, I. Dimitrova, S. Georgieva
Abstract. The aim of the study is to determine the parameters of the biological fertility and milk production of sheep breed Dairy Synthetic Population from herd of the Agricultural Institute, Shumen. The survey covers 851 ewes born in the period 2004 – 2008. Biological fertility of ewes is dependent on the order of lambing, and is the lowest on the 1st (1.24) and the highest on the 3rd lamb (1.52). In animals from line 51 (a cross breed with Chios) it is the highest on 2.5 years old –1.56, on 3.5 years old – 1.67, on 4.5 years old – 1.90, as fertility of the sheep of the leading pure-bred lines is 1.27, 1.42 and 1.49. The average milk yield for standard 120-day milking period of sheep in the flock is the highest in animals from line 51 and on the 1st lactation it is by 23.7% and on the 2nd by 15.07% higher than in pure-bred lines. The value of the heritability (h2) of the studied traits is low to medium.