Ultrasonographic monitoring of artificially stimulated ejaculation in three rhinoceros species (Ceratotherium simum, Diceros dicornis, Rhinoceros unicornus)

Manual massage of the penis and rectal electroejaculation methods have been minimally effective for collecting semen from the rhinoceros. These two me thods for stimulating ejaculation were evaluated by rectal ultrasonography. One individual each of three rhinoceros species (Ceratotherium simum simum , Rhinoceros unicornis and Diceros bicornis) was stimulated by manual massa ge of the penis and two black rhinoceroses (Diceros bicornis) were electroe jaculated. On ultrasonography, neither manual massage nor rectal electroeja culation affected the accessory glands. The pelvic urethra remained empty d uring manual massage of unconditioned animals; however, this area was fille d before commencement of massage of conditioned animals. The pelvic urethra also filled during electroejaculation. Semen accumulated in the pelvic ure thra during pauses between electrical stimulations and was moved distally i nto the penile urethra by rectal and penile massage. The volumes of seminal fluid recovered from electroejaculation in this study exceeded previously reported attempts. This study demonstrated the potential of transrectal ima ging for improving the recovery of semen by these methods.