Revue d’Elevage et de Médecine Vétérinaire des Pays Tropicaux (Jan 2005)
Numerical and Weight Productivities of Crossbred D’man by Local Queue Fine de l’Ouest Ewes
Abstract
Productivity of F1 crossbred ewes between the prolific D’man and the local Queue fine de l’Ouest breeds (D’man x QFO) mated with terminal sires of the Brune noire de Suisse (BNS) breed was evaluated and compared to that of (i) QFO and D’man ewes respectively mated to rams of the same breed in a research station (ESAK) and of (ii) QFO ewes mated to rams of the same breed in a commercial farm (El-Mabrouka). In ESAK station, data collected between 1995 and 2003, and related to 343, 168 and 323 lambings of QFO, D’man, and F1 crosses D’man x QFO ewes, respectively, were used. At birth, the mean litter size was 1.17 ± 0.37, 1.76 ± 0.71, and 1.40 ± 0.54 for ewes of the QFO, D’man, and crosses D’man x QFO genotypes, respectively, whereas at 90 days after lambing, the corresponding figures were 1.13 ± 0.40, 1.65 ± 0.70, and 1.31 ± 0.54. The year of lambing, genotype of the ewe as well as their interaction were significant sources of variation of all litter sizes. At 10 days after lambing, the weight productivity of QFO ewes was 7.3 ± 2.5 kg, and was thus significantly higher (p < 0.05) than that of D’man (6.6 ± 2.7 kg), and D’man x QFO (7.0 ± 2.3 kg) ewes. This trend was reversed 90 days after lambing with weight productivity of D’man x QFO, and D’man ewes reaching 22.9 ± 7.7 and 22.5 ± 12.0 kg, respectively, and that of QFO sheep 19.5 ± 6.7 kg. With the exception of the age of the ewe, all other sources of variation highly influenced (p < 0.001) most weight productivity traits. In El-Mabrouka farm, the data used concerned 1048 and 529 lambings of QFO, and D’man x QFO breeds, respectively, that occurred during years 1999, 2000 and 2001. The year of lambing, genotype of the ewe as well as its age were highly significant sources of variation for the litter size at birth. Crossbred ewes produced on average 0.2 lamb more than QFOs (p < 0.05). Difference in productivity at 70 days after lambing was approximately 3 kg in favor of D’man x QFO ewes and sources of variation retained in the model significantly affected (p < 0.05) productivity traits. The achieved levels of improvement in the productivity might not justify the adoption of such a crossbreeding scheme, which is laborious to implement and requires a lot of strictness at the field level.
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