Performance of 407 yearlings representing 7 genetic groups born in February - March and mated at 8-9 months of age was evaluated. Romanov
 (R) first cross (FC) and backcross (BC) ewe lambs were the heaviest at birth (3.9 and 4.1 kg) followed by Booroola (B) and Flnnsheep (F) crosses, respectively. They were also the heaviest groups at 50, 100 and 365 days of age followed by F then B crosses. Fertility for R, FC (987.)
 and BC (94%) was significantly higher than that of F (88 and 78%) and B crosses (51 and 68%), respectively. Prolificacy was highest 1n R, FC. Booroola and F, FCs were similar In lamb production. The same tendency was observed 1n BC. Lamb survival ranged between 93 and 97% at birth and
 between 85 and 92% between birth and weaning. The heaviest Utters at birth were those of R, FC (6.4 kg), for the other groups the weight varied between 5.2 and 5.8 kg. Litter weight at weaning ranged between 25 kg for R, FC and 19 kg for B crosses. In FC, Booroola yearlings produced 3.7 kg of wool compared to 3.2 kg for F and R. In backcross F and R clipped 3.1 kg, 0.3 kg lighter than B.

M. H Fahmy

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume XV. Beef cattle, sheep and pig genetics and breeding, fibre, fur and meat quality., , 369–372, 1990
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