The effect of the age аt conceiving on the productivity traits at dairy ewes in Bulgaria

The aim of the research was to study the effect of the age at conceiving on the productivity traits of sheep from Synthetic population Bulgarian milk in Bulgaria. The experiment was conducted with 20 ewes traditionally conceived at the age of 18 months and 20 ewes conceived as ewe lambs at the age of 11 months on first lactation and their lambs (47) reared in IAS – Kostinbrod, Bulgaria. The 120 days milking milk production and that after 120 days until the end of lactation were determined by the AC method of ICAR. The days after the standard period until the end of lactation were registered. The milk composition was measured by milk analyzer Ekomilk, Bultech Company, Bulgaria. The live weighs were measured. The fecundity was determined. With the exception of the fecundity and the standard 120 days milking milk production the age at conceiving influences significantly the live weigh before conceiving, birth live weight of lambs, the duration of the milking period and the milking milk yield (P is less than 0.01; P is less than 0.001). The traditionally conceived ewes had significantly higher live weight before conceiving (52.31 kg), of newborn lambs (5.05 kg), the duration of milking period (187 days) and milking milk yield (130 L) than the early conceived (40.53 kg; 4.16 kg; 120 days; 80.24 L) (P is less than 0.01; P is less than 0.001). For the fecundity and the standard 120 days milking milk production no significant differences were found between the groups (1.08% and 1.25%; 92.27 L and 80.24 L). Significant difference in the milk composition of the ewes conceived at 18 month age compared to the conceived at the age of 11 months (P is less than 0.05; P is less than 0.001) was found. The obtained results provide useful information for the implementation of suitable management decisions for early conceiving of the ewes from Synthetic population Bulgarian milk for production of lambs and milk at the farm practice.