Evaluation of the semen quality and reproductive performance of trypanotolerant Djallonké rams following an artificial infection with Trypanosoma congolense

Following an experimental infection with Trypanosoma congolense, the semen quality and reproductive performance of 17 mature Djallonké rams was studied during a period of 26 weeks. The rams were randomly divided into three groups, namely one control group (G1) and two infected groups (G2 and G3). During the 5 weeks pre-infection the normal semen parameters were assessed. Following infection, moderate clinical symptoms associated with trypanosomosis were seen among the infected rams. Thirteen weeks post-infection, diminazene aceturate was administered to group 3. Both the treated group and the control group had significantly better weights than the infected group in the period following the trypanocidal treatment. The impact of trypanosomosis on the reproductive performance of the rams was seen in reduced libido with a higher rate of refusals and on semen quality with some temporary effects on mass motility, percentage live sperm cells and minor sperm cell abnormalities. However, these temporary changes in semen parameters were not significant when analysed as impact of infection. From the present study it was concluded that reproductive performance was not significantly impaired following artificial T. congolense infection. In addition, the Djallonké rams also showed an important clinical tolerance. However, significant differences between rams indicated a large variation in clinical response and reproductive performance following trypanosome infection.