WEIGHT GROWTH OF ILE DE FRANCE LAMBS ACCORDING TO THE GENEALOGY LINE

The aim of the study was to compare the weight growth and average daily gain of Ile de France lambs of different sex and type of birth according to the genealogy line. The study was conducted with 153 Ile de France lambs reared in the Institute of Animal Science – Kostinbrod. The lambs were offspring’s of three imported rams (№ 3015, 3127 and 3323) founders of the genealogy line in the fl ock. The weight growth of 63 male and 90 female lambs born as single (62) and twins (91) was traced. The lambs were divided in three groups according to their origin: I group – of ram № 3015, II group – of ram № 3127, III group – of ram № 3323. 612 measuring of live weight at birth, at 10 days, at 30 days and at 70 days (± 2 days) were made. The average daily gain between 10–30 days and 30–70 days was calculated. The age to measure the weights and defi ne the average daily gain considered the selection requirements of the specialized meat breeds. The obtained information was evaluated by the methods of variation statistics. The parameters of the live weight and the average daily gain of Ile de France lambs from three genealogical lines at different ages, sex and type of birth were established as a result of the present study. No essential differences in the live weight and the average daily gains of the different ages in the male and female single and twins from the studied genealogical line were observed. The average values of the weight at birth, at 10, 30 and 70 days (4.89 kg, 7.72 kg, 13.19 kg and 24.53 kg) and the average daily gain between 10-30 days and 30-70 days (0.270 kg and 0.285 kg) respond to the standard of the breed and showed that appropriate selection was done in the particular conditions of rearing in IAS – Kostinbrod.