Male horses, known as stallions, possess a prostate gland as a normal part of their reproductive anatomy. This gland is classified as an accessory sex gland, similar to those found in other male mammals, including humans and dogs. Its existence is tied directly to the production of seminal fluid, which is necessary for successful reproduction. This organ performs a specialized function and is susceptible to specific health issues that can affect the stallion’s fertility.
The Equine Prostate Gland: Location and Structure
The equine prostate gland is situated deep within the pelvic cavity, lying in the retroperitoneal region. It is located at the neck of the urinary bladder and surrounds the cranial portion of the pelvic urethra. Anatomically, the stallion’s prostate is considered a compact type of gland, differing from the more diffuse structure seen in some other species.
The gland consists of two distinct lateral lobes connected by a band of tissue called the isthmus. These lobes are positioned dorsal to the pelvic urethra, sitting at the junction where the bladder empties into the urethra. A healthy prostate lobe typically measures about 7 centimeters long, 4 centimeters wide, and 1 centimeter thick. The connecting isthmus is approximately 3 centimeters in length.
Primary Function in Reproduction
The primary role of the prostate gland is to contribute a significant portion of the seminal plasma, the non-sperm fluid component of the ejaculate. This fluid is discharged alongside secretions from other accessory sex glands to form a complete ejaculate. The prostate’s secretion acts as a vehicle, providing a liquid medium that aids in the transport of spermatozoa through the female reproductive tract.
The fluid contains specific biochemicals essential for sperm viability and function. Prostatic secretions include various electrolytes, citric acid, and zinc. These components buffer the environment, protecting the sperm from the naturally acidic conditions of the urethra and the female tract. The secretions also provide metabolic support and energy sources for the sperm cells, maintaining their motility and survival after ejaculation.
Common Equine Prostate Health Concerns
Prostatic disease is less common in horses than in dogs or men, but several conditions can affect the gland, potentially compromising fertility and urinary function. The most frequently observed issue is prostatitis, the inflammation or infection of the prostate tissue. This condition is often bacterial and can occur in both sexually intact stallions and geldings, though it carries greater significance for breeding animals due to its impact on semen quality.
Another condition is benign prostatic hyperplasia (BPH), the non-cancerous enlargement of the gland typically associated with aging and hormonal influences. Though rare, neoplasia, such as adenocarcinoma, can also affect the equine prostate. Owners might observe clinical signs such as difficulty or pain during urination or defecation, resulting from the enlarged gland pressing on the urethra or rectum. In stallions, symptoms can also include decreased libido, pain during ejaculation, and a decline in semen quality.
Veterinarians diagnose prostatic issues using a combination of methods, including a rectal palpation to assess the gland’s size, symmetry, and texture. Transrectal ultrasonography provides detailed imaging of the prostate structure and can identify inflammation, abscesses, or abnormal growths. Treatment varies based on the specific condition, involving antibiotics for infection or, for BPH in non-breeding animals, castration to induce glandular regression.