Reproductive biology of donkey. I. Testicular measurement and sexual behaviour at semen collection

Abstract

Testicular measurements and sexual behaviour at semen collection of six donkeys of the “Pega” breed, ranging from 3 to 9 year of age were studied. The average testicular lenght, widht and height were, respectively, 10.12 x 7.38 x 7.68 cm for the left testicle and 10.35 x 6.73 x 7.12 cm for the right one. No statistical difference was found between left testicular volume (x = 201.36 cm³) and right testicular volume (x = 182.34 cm³) of the same sire. The reaction time (measured from the first visual contact with the female to ejaculation) ranged from 2 to 45 minutes and the overall mean was 10.98 ± 6.48 min (n=68). During the teasing period some reactions, considered characteristic of donkeys by others investigators, was observed. These included mounting without penis erection or with partial penis erection, flehmen and mastigatory movements of the type described as an oestrous symptom in jennets.