Sexual Behavior and Hormonal Profiles in Arab Stallions

One hundred ninety ejaculates were collected from 16 healthy Arab stallions (5–18 years; 12 normal and four slow breeders) over 12 months, and sexual behavior parameters were recorded. Serum samples were collected from stallions for determination of testosterone, estradiol-17β, cortisol, and glucose. The results revealed that the time to first mount, latency to erection, latency to mount, and number of mounts per ejaculate were significantly (P < .001) shorter in normal breeders (61.12 ± 5.18, 49.45 ± 3.78, 82.54 ± 6.39, and 1.32 ± 0.04, respectively; n = 12) than in slow breeder stallions (259.82 ± 42.66, 228.26 ± 50.48, 371.95 ± 36.27, and 2.63 ± 0.35, respectively; n = 4). Sexual behavior abnormalities constituted 10.42% of all trials. Season exerted a significant (P < .05) effect on all sexual behavior parameters except latency to ejaculation, which was the shortest during spring in the normal breeders. Sexual behavior abnormalities were significantly (P < .05; 37%) higher in all stallions during autumn. Both serum estradiol-17β and cortisol levels rose significantly (P < .05) after semen collection in all stallions. Serum estradiol-17β level was significantly (P < .05) increased during spring and summer in all stallions. Cortisol levels were significantly (P < .05) higher during autumn in both normal and slow breeder stallions (2,121.15 ± 115.55 and 69.37 ± 21.84 pg/mL, respectively). In conclusion, sexual behavior parameters in normal breeders were shorter in duration than that recorded in slow breeder stallions. Season affects sexual behavior parameters and serum estradiol-17β levels, with the highest values found during spring and summer. Estradiol-17β and cortisol were the two hormones responsible for sexual behavior in stallions. The best sexual behavior was accompanied by low levels of serum testosterone.