Trypanosomosis and reproduction: I. Effect of Trypanosoma vivax infection on the oestrous cycle and fertility in the ewe

Ten West African Dwarf ewes were inoculated with Trypanosoma vivax and, at varying intervals, treated subcuratively with diminazene aceturate to maintain the infection. Soon after infection all ewes had anoestrus for 40 to 96 days and 5 died by day 110 post infection. Compared to control animals, infected ewes had prolonged low levels of plasma progesterone until recovery or death. However, no gross or histological lesions were detected in the endocrine or reproductive organs. Of the survivors, the 5 that were aparasitaemic subsequently became pregnant and had normal gestations.