Abstract
Two hundred Djallonké ewes were subjected to natural mating to measure the impact of ram weight selection on offspring. The animals were divided into 10 groups of 20 ewes each, and were allocated rams from the National Sheep Selection Programme and other non-selected rams acquired on the local market. The genetic type (selected or non-selected) of rams had no significant effect on the weight of their offspring, except for weight at 80 days of age. The interaction between type of birth of lamb and genetic type of ram had a moderate (P<0.05) effect on 80- and 180-day weight. Genetic type and its interaction with lamb sex and birth type had an important effect (P<0.05) on daily weight gain between 30 and 80 days. On average, lambs from selected rams were 300, 800 and 500 g heavier than lambs from non-selected rams at 30, 80 and 180 days, respectively. This was equivalent to an average genetic gain of 5.6, 9.3 and 3.5%, respectively. From birth to 30 days and from 30 to 80 days of age, daily weight gains of lambs from selected rams were respectively 9 and 10 g higher than those of lambs from unselected rams. This represented a genetic gain of 7.8 and 15.6%, respectively, compared to average daily weight gains of lambs from unselected rams.
