The effects of a strategic supplementation and prophylaxis on the reproductive performance of primiparous Fulbe ewes in the semi-arid zone of Cameroon

The semi-arid zone of Cameroon has 2.869 million sheep, representing 59 of the national population. Despite the important economic, traditional, social and religious roles they play, their productivity is seriously hampered by high mortalities due to mixed infections by 'peste des petits ruminants' (PPR) and gastro-intestinal helminthoses, and also by poor feeding and management. This study evaluated a combination of a protein supplement with a prophylactic plan on the reproductive performance of primiparous ewes, the growth and the viability of their lambs. A number of 164 ewes aged 12-15 months, were maintained in four flocks: supplemented and treated, supplemented, treated, and control groups. Protein supplementation consisted of feeding 200 g cottonseed meal per ewe per day. Prophylactically treated flocks were dewormed at the beginning and at the end of the rainy season, sprayed whenever ticks were found, and vaccinated against PPR. Results indicated no interaction between supplementation and prophylaxis for the reproductive, growth and mortality parameters. Supplementation increased ewes' body weight at lambing (P<0.001) and the fertility rate (P<0.05). Fertility increased with ewes' weight at mating, and a good prediction (P<0.001) was obtained with a logistic regression model. Lambs' birth weight increased (P<0.001) with supplementation and ewes weight at lambing. Supplementation increased (P<0.005) lambs' weight at weaning and reduced the mortality' rate (P<0.001). High mortality in lambs before weaning was related to lower birth weight, and was well predicted (P<0.001) with a logistic regression model. Total litter weight weaned was similar between all types of birth; consequently, there was no advantage of multiple births under our experimental conditions. This study implies that protein supplementation is an efficient strategy to reduce nutritional stress in premiparous Fulbe ewes and increase their productivity. However, factors affecting lamb mortality in multiple births need further examination.