GROWTH OF LAMBS OF THE ILE-DE-FRANCE BREED FROM BIRTH TO WEANING AND FACTORS AFFECTING IT.

The present study examines the growth of lambs of the Ile-de-France breed from birth to weaning (at 70 days old). The research involves 1662 lambs born in the period 2017-2018. The animals are bred under similar technological conditions in three farms located in Northern Bulgaria which are controlled by the Ile-de-France Breeders Association in Bulgaria (AILFB). It has been ascertained that the male lambs are born with an average live weight of 4.531 ± 0.042 kg, they reach 14.90 ± 0.078 kg at 30 days old, and 27.31 ± 0.155 at 70 days old, while the female lambs - 4.462 ± 0.043, 14.74 ± 0.085, and 27.56 ± 0.158, respectively. The gender is not a reliable source of variation regarding this parameter. The farm, year, season and month of birth, father and mother factors have a complex interrelationship but, as a whole, the farm and the father are the factors which influence significantly the live weight of lambs at birth and their growth until 70 days old. It has been established that it is possible the growth of lambs to be regulated by modelling the genetic and environmental factors influencing it. [ABSTRACT FROM AUTHOR]