Differences in reproductive efficiency between female sheep of the Queue Fine de l'Ouest purebreed and their first cross with the D'Man

Abstract

Ovarian status at 8 months of age, attainment of puberty, fertility and litter size were compared for Queue Fine de l'Ouest (QFO) ewes and their D'Man × QFO contemporaries. At 8 months of age, the percentages of ewe lambs cycling as indicated by the presence of corpora lutea were 91.6 and 20.0% for the D'Man × QFO genotype and the QFO breed respectively (P < 0.001 ). In a second trial, the cumulative percentage of ewe lambs ovulating at least once up to 10 months of age were 54.5 and 6.2% for the D'Man × QFO genotype and the QFO breed respectively (P < 0.01). Breed of sheep had the most significant effect (P < 0.001) on fertility following early breeding of ewe lambs with values of 83.8 and 33.3% for animals of the D'Man × QFO genotype and the QFO breed respectively. For animals of the two breeds mated at either 18 or 30 months of age, lamb production increased by 0.29 lambs per ewe lambing in D'Man × QFO ewes as compared with QFO. It is concluded that crossing with D'Man improves reproductive performances of the native QFO ewes under semi-arid, grazing systems.