LAMB AND MILK-PRODUCTION OF AWASSI AND EAST-FRIESIAN SHEEP AND THEIR CROSSES UNDER MEDITERRANEAN ENVIRONMENT

Data on lambs born per ewe put to the ram (LB/EP), lambs born per ewe lambing (LB/EL), milk production through lactation and lactation lengt h up to six lambings of 603 Awassi (A), East-Friesian (EF), A x EF (F1 ), F1 x F1 (F2), EF x F1 (1/4A), 1/4A x F1 (3/8A(1)) and 3/8A(1) x 3/8 A(1) (3/8A(2)) ewes bred in the same flock in the years 1956-1971 were analysed, The data were obtained from 2293 ewe-years, 1993 lambings a nd 1698 lactations. Genotype, age at lambing and sire within genotype had an (P < 0.05) effect on each trait. Effect of year of birth, genot ype by age at lambing interaction and genotype by year of birth intera ction were significant (P < 0.05) for milk production but not for lamb production. The effects of litter size on milk yield and lactation le ngth were not significant, Least squares means (LSM) of LB/EP were hig hest in 3/8A(2) (1.48) and lowest in Awassi (0.98), LSMs of LB/EL were highest in EF (1.60), and lowest in Awassi (1.11). The LSMs of milk y ield of A, F1, F2 and 3/8A(2) were similar, ranging from 223 to 248 1. The milk yield of EF was the lowest: only 161 1. The LSMs for lactati on length were similar in all genotypes, about 198 days except for 1/4 A and EF which had shorter (P < 0.05) lactations. The Awassi-transmitt ed effects were positive (P < 0.001) for lactation length and milk yie ld, and negative (P < 0.001) for LB/EL, Heterosis (P < 0.001) was foun d for LB/EL, milk yield and lactation length, Recombination effect was not significant for any trait.