Long-term effects of an experimental infection with Trypanosoma congolense on reproductive performance of trypanotolerant Djallonke ewes and West African Dwarf does

Ten West African Dwarf (WAD) does and 12 Djallonke ewes were artificially infected with a West African strain of Trypanosoma congolense and observed over two years. The infected animals showed a chronic anaemia together with a persistent parasitaemia but very low mortality and increase in body weights was not significantly different from the control. In the infected sheep significant differences were found in offspring production at three and five months due to a higher mortality among the lambs. The infected goats had more abortions and stillbirths and period to first kidding, total number of parturitions, production at birth, one, three and five months were significantly different from the controls. A productivity index was calculated and revealed that a chronic T congolense infection significantly decreases the productivity of WAD goats during two years whereas in Djallonke sheep, the loss in productivity is recovered after one year. Although both species are regarded as trypanotolerant, the Djallonke sheep show a better tolerance to a chronic T congolense infection that the WAD goats.