dth: 0px; "> Gonadal and extragonadal sperm reserves of 12 Yankasa rams aged 18-24 months, were determined following experimental Fasciola gigantica infection over a 12 week study period. Seven out of the 12 rams serving as the infected group were orally inoculated with 800 Fasciola gigantica metacercariae while the remaining 5 rams serving as control were orally give normal saline, and monitored for 12weeks before removal of the testes by open castration. The dimensions of the testicles and epididymis were recorded, gonadal and extragonadal sperm reserves of Yankasa rams were determined using haemocytometer. Mean (±SEM) sperm count in testes and epididymides were 136.0±70.0a and 55.4±43.5a and 377.0±0.0b and 284.7±0.0b respectively for infected and control groups. The mean (±SEM) of the caput, corpus, and cauda of the infected and the control rams were 53.5±53.5a, 16.0±8.0a, 95.0±69.0a and 310.0±0.0b, 140.0±0.0b, 404.0±0.0b respectively. This study revealed a significant decrease (p<.0.05) in gonadal and extragonadal dimensions and sperm reserves of Yankasa rams infected with Fasciola gigantica when compared to the control.