Goot, H., Institute of Animal Science, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
Eyal, E., Institute of Animal Science, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
Folman, Y., Institute of Animal Science, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
Foote, W.C., International Sheep and Goat Institute, Utah State University, Logan, UT 84322, United States

Results based on contemporary comparisons of F1 progeny by Finnish Landrace and Romanov rams out of Mutton Merino and Awassi ewes are given. Within the four genotypes thus produced, the F1 females were mated to F1 males to produce F2 progeny. Mutton Merino crosses were carried through the first lambing and the Awassi crosses through two lambings. All animals were housed and lambs reared on ad lib. concentrates and hay. There were no significant differences between sire breeds in the performance of their F1 progeny except for wool traits. Awassi crossbred females at 1 year old exceeded the Mutton Merino crosses in proportion lambing (74 vs 65%); lambs born per ewe mated (1.15 vs 0.95); birth weight (5.1 kg vs 4.2) and 150-day weight (46 kg vs 43). Lamb mortality up to 150 days was similar at around 24%. For the Awassi crossbreds at the second lambing the F2 progeny with finn blood were heavier at birth and grew faster to weaning than those with Romanov blood (4.1 kg and 233 g/day vs 3.6 kg and 198 g/day). Romanov rams either introduced or greatly increased the incidence of pigmented and kemp-like fibres in the wool of their progeny; in the cross with Mutton Merinos they also adversely affected breed type, character and handle. © 1979.