Performance of Djallonke sheep under an extensive system of production in Faranah, Guinea

A total of 147 ewes, 4 rams and 188 lambs of their progeny of the Djallonke breed of sheep were used to study the factors affecting reproductive and g rowth traits and the causes of lamb mortality. Data on ewes were collected during a 12-month period, while those on the lambs born to 123 of the ewes were collected until they were 12 months of age. The average fertility and abortion rates were 0.84 and 0.09. The fertility rate increased and the abo rtion rate decreased with increasing age of the ewes (p<0.05). The number o f lambs born per ewe joined, litter weight at birth per ewe joined and litt er weight at weaning per ewe joined were 1.28, 3.5 kg and 17 kg, respective ly. The average numbers of lambs born per ewe, lambs born alive per ewe, la mbs born dead per ewe and lambs per ewe that died between birth and weaning were 1.53, 1.43, 0.03 and 0.3, respectively. The age of the ewes significa ntly (p<0.05) affected all these traits except the number of dead lambs and the index of fertility (94%). The age of the ewes significantly (p<0.05) a ffected the birth weight and the weight at 6 and 12 months of age, whereas the lambing season significantly (p<0.05) affected all the growth traits st udied. The type of birth was the most important source of variation in body weights of lambs. Sex had no significant (p>0.05) effect on the growth tra its studied. The complex `starvation-bad management-light body weight at bi rth' caused 48% of the lamb mortality between birth and weaning, while diar rhoea, pneumonia and internal and external parasites caused approximately 5 2% of the lamb mortality over the same period. The seasonal raw mortality r ate of the lambs before weaning was highest in the humid season.