Endocrine Response Tests for Fertility Assessment in Awassi Rams in Jordan

The obective of this study was to determine testosterone profiles in fertile and subfertile Awassi rams, and to develop endocrine response tests for investigating subfertility. Nine Awassi rams were divided equally into three groups: low (LF), medium (MF) and high (HF) fertility groups. Semen quality, testicular and epididymal ultrasonic images and testosterone (T) profile were examined for all rams. Results indicated that both ultrasonographical images of testicles and semen parameters did not differ significantly among groups. Motility and concentrations of the sperms were lower in the LF (58.8±13.3 % and 0.9±0.5×109/ml, respectively) group. Testosterone concentrations were significantly higher in HF (2.7±0.1 ng/ml) group compared to the other groups (0.99±0.2 and 0.7±0.1 ng/ml for LF and MF, respectively). Three small doses of Gonadotrophin Releasing Hormone (GnRH) and Human Chorionic Gonadotrophin (hCG) injections resulted in significantly lower testosterone concentrations in LF (3.2±0.2 and 2.9±0.3 ng/ml, repectively) group than the other ones. In conclusion, T profile and hCG response tests can be used to determine subfertile rams that passed breeding soundness exam