Impact of ticks on the growth rate of the Djallonke lambs.

The effect of ticks infestation on growth rate in naturally infested lambs was studied during eight months (September 1997 - April 1998). Sixty three lambs were used, which were divided into three groups containing each 21 an imals (6 males and 15 females). Ticks were collected every day on animals o f group 1 and monthly in group 2. Group 3 was used as control group. Body w eights were recorded weekly. Ticks identification revealed the presence of Amblyomma variegatum and Rhipicephalus sp. which represented 80.9 % and 19. 1 % of the total (735 parasites) respectively. Lamb growth varied from one group to the other : 50.4 +/- 1.2 g, 42.5 +/- 8 g and 42.2 +/- 7 g in group s 1, 2 and 3 respectively; the difference was significant (P < 0.01) betwee n group 1 and the other groups. The study indicates that growth, especially before weaning, seems to be reduced by ticks.