The effects of Trypanosoma brucei experimental infection on hormones during synchronized oestrous cycle and pregnancy, and pregnancy outcome were investigated using 39 West African Dwarf goats (3 bucks, 36 does). Bucks were kept separate in a pen and the does in groups of six. They were fed with concentrate at 0.25kg per head/day. Elephant grass and fresh water were provided ad libitum. Infected does were inoculated with 4.8×105 trypanosomes while synchronization was achieved through two intramuscular injections of 5 mg Lutalyse® 7 days apart. Venous blood was centrifuged at 3000g and serum was stored under ice in a chest freezer. Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), oestradiol and progesterone were evaluated using enzyme immunoassay. The differences between proestrual values of control and infected does for LH (0.25±0.10, 0.10±0.06) IU/L, oestradiol (0.31±0.04, 0.58±0.03 pmol/l) and progesterone (5.63±2.05, 17.60±0.68 nmol/l) respectively were significant (P<0.05), except for FSH (0.40±0.20, 0.40±0.07 IU/L). The differences between oestrual values of control and infected does for FSH (0.28±0.01, 0.11±0.04), LH (0.28±0.04, 0.11±0.61), oestradiol (0.69±0.04, 0.50±0.03) and progesterone (0.83±0.09, 11.63±6.13) were significant (P<0.05). Between control and infected does, the differences in dioestrual values for these hormones, and progesterone during pregnancy were not significant (P>0.05). Abortion occurred within 46 and 32 days in does infected during first and second trimesters respectively. The study showed that experimental Trypanosoma brucei infection caused fluctuations in hormone concentration during the proestrual and oestrual stages of the oestrous cycle, and abortion, to which the does were more vulnerable during the second trimester. 1365263763.php