Genetic and environmental effects on growth to 1 year and viability of lambs from a crossbreeding study of D'man and Sardi breeds

Abstract

Genetic effects were estimated for growth to 1 yr and viability to 90 d of 882 lambs from a diallel cross of Sardi (S), D'man (D), and D'man x Sardi (DS) male and female parents. Sardi direct genetic effects were significantly higher than those of D'man for weights at birth and up to 2 mo, but the difference decreased thereafter and was in favor of D'Man at 6 mo. Sardi maternal ability was better than that of D'man for weights at all ages. Estimates of individual heterosis were small and negative for weight at birth, weight at 1 mo, and lamb viability and positive for other body weights; the estimate was significant for 12-mo weight. Estimates of maternal heterosis were small and did not approach significance for any trait. Epistatic recombination effects were generally small, but negative for all traits and significantly so for viability to 30 d. In general, the results, combined with those on reproduction and total lamb production of ewes of these groups, reported elsewhere, indicate that a population produced by inter se mating of animals 50% D, 50% S breeding is expected to have higher total lamb production than either purebred.

Some reproductive and growth traits of crossbred genotypes produced by crossing local sheep breeds of Kivircik x White Karaman and Chios x White Karaman in steppe conditions

“…That the survival of C-sired and Ksired lambs in steppe conditions were similar to W lambs are beneficial for lamb production. Lamb survival was lower for lambs from young ewes than from ewes at intermediate ages, in agreement with the results of majority of the published studies (BOUJENANE et al, 1991;BUNGE et al, 1995;AKCAPINAR et al, 2000;UNAL et al, 2002b). In this study, male and female lambs did not differ in terms of survival rate, in agreement with the results from other studies (BOUJENANE et al, 1991;UNAL et al, 2002b) although a more common pattern is for lower survival for males (GALLIVAN et al, 1993;BUNGE et al, 1995;AKCAPINAR et al, 2000).…”

“…Booroola Merino sired F 1 ewes and Finnsheep sired F 1 ewes had more litter size and longer breeding season than hair breeds sired F 1 ewes. The crossbred ewes produced from prolific D'man breed and indigenous Sardi breed had higher total lamb production than either purebred (BOUJENANE et al, 1991). OZCAN et al (2001) reported that Chios x Kivircik F 1 ewes had higher reproductive performance than Kivircik ewes.…”

“…Lamb survival was greatly influenced by litter size. In general, an increasing litter size increases losses in a more or less exponential way, especially when the environmental conditions are unfavorable (BOUJENANE et al, 1991;UNAL et al, 2002b;KALLWEIT and BAULAIN, 2001). Higher ovulation rate generally leads to higher embryonic mortality.…”

Productivity of Timahdite and D’man × Timahdite ewes lambing in the autumn, spring and summer in Morocco

“…The low birth weight of D × T progeny may be due to their higher litter size, which is the result of genes inherited from their D'man maternal grand-sire. Boujenane et al [4] found that the birth weights of twin and triplet lambs were 79% and 63%, respectively, of the birth weight of singles. Moreover, Boujenane et al [4] reported that the linear regression coefficient of birth weight on percentage of D'man inheritance was -18 g. Likewise, El Fadili et al [10] observed a decrease in birth weight in relation to the percentage of D'man breeding.…”

“…Boujenane et al [4] found that the birth weights of twin and triplet lambs were 79% and 63%, respectively, of the birth weight of singles. Moreover, Boujenane et al [4] reported that the linear regression coefficient of birth weight on percentage of D'man inheritance was -18 g. Likewise, El Fadili et al [10] observed a decrease in birth weight in relation to the percentage of D'man breeding. Also, Cochran et al [8] found that lambs from 1/4-Finnsheep, 3/4-Dorset ewes were 0.64 kg lighter at birth than lambs from purebred Dorset ewes.…”