Management of Anejaculation in a Stallion Associated With Neurologic Deficits

Anejaculation is the most common cause of ejaculatory dysfunction in the stallion.1 A 9-year-old Andalusian stallion was presented with a history of normal libido, but refusal to either mount the phantom or inability to ejaculate when mounted on the phantom. The stallion had a two year history of hind limb weakness, intermittent urine dribbling, and inability to completely void his bladder. He tested negative for equine protozoal myeloencephalitis (EPM) in October 2011.
A lameness examination was normal, but a neurologic examination identified hind limb incoordination, including cross-cantering and 1.5/5 and 1/5 ataxia on the right and left pelvic limbs, respectively. At presentation, the stallion did not ejaculate on the first two attempts and was weak when dismounting (knuckled over at the fetlock and slid off the phantom). Attempts at ground collection and chemically induced ejaculation were not successful. Four days after admission, the stallion did not urinate within a 24 hour period. Transrectal ultrasonography revealed a greatly distended bladder (>12cm depth). The bladder was catheterized and drained (12 L). Multiple ejaculates were subsequently obtained using a combination of a live jump mare, a long Missouri AV and hot towels, concurrent with administration of phenylbutazone (BID). In addition, imipramine hydrochloride (1.0g PO) and gonadltropin releasing hormone (GnRH; 50µg IV) were given two hours prior to collection, with a similar dose of GnRH given one hour prior to collection.
Anejaculation is a relatively common condition in stallions and can be caused by neurologic deficits. This stallion exhibited neurologic limitations manifest by an inability to urinate, incoordination, and hind limb ataxia. Despite the deficits, accommodations to enhance sexual arousal such as imipramine,2 GnRH,3 and a live mare mount combined with enhanced penile stimulation (hot towels) were introduced that allowed semen to be collected routinely.