A testicle or testis is the male gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testicles are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone, whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone.
Castration is any action, surgical, chemical, or otherwise, by which a male loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy, while chemical castration uses pharmaceutical drugs to deactivate the testes. Castration causes sterilization ; it also greatly reduces the production of hormones, such as testosterone and estrogen. Surgical castration in animals is often called neutering.
A gelding is a castrated male horse or other equine, such as a pony, donkey or a mule. The term is also used with certain other animals and livestock, such as domesticated camels. By comparison, the equivalent term for a castrated male bull would be ox, or a wether for rams and billy goats.
Testicular cancer is cancer that develops in the testicles, a part of the male reproductive system. Symptoms may include a lump in the testicle or swelling or pain in the scrotum. Treatment may result in infertility.
Cryptorchidism, also known as undescended testis, is the failure of one or both testes to descend into the scrotum. The word is from Greek κρυπτός 'hidden' and ὄρχις 'testicle'. It is the most common birth defect of the male genital tract. About 3% of full-term and 30% of premature infant boys are born with at least one undescended testis. However, about 80% of cryptorchid testes descend by the first year of life, making the true incidence of cryptorchidism around 1% overall. Cryptorchidism may develop after infancy, sometimes as late as young adulthood, but that is exceptional.
A hydrocele testis is an accumulation of clear fluid within the cavum vaginale, the potential space between the layers of the tunica vaginalis of the testicle. It is the most common form of hydrocele and is often referred to simply as a "hydrocele". A primary hydrocele testis causes a painless enlargement in the scrotum on the affected side and is thought to be due to the defective absorption of fluid secreted between the two layers of the tunica vaginalis. A secondary hydrocele is secondary to either inflammation or a neoplasm in the testis.
Neutering, from the Latin neuter, is the removal of a non-human animal's reproductive organ, either all of it or a considerably large part. The male-specific term is castration, while spaying is usually reserved for female animals. Colloquially, both terms are often referred to as fixing. In male horses, castrating is referred to as gelding. An animal that has not been neutered is sometimes referred to as entire or intact.
Orchiopexy is a surgery to move and/or permanently fix a testicle into the scrotum. While orchiopexy typically describes the operation to surgically correct an undescended testicle, it is also used to resolve testicular torsion.
An inguinal hernia or groin hernia is a hernia (protrusion) of abdominal cavity contents through the inguinal canal. Symptoms, which may include pain or discomfort especially with or following coughing, exercise, or bowel movements, are absent in about a third of patients. Symptoms often get worse throughout the day and improve when lying down. A bulging area may occur that becomes larger when bearing down. Inguinal hernias occur more often on the right than left side. The main concern is strangulation, where the blood supply to part of the intestine is blocked. This usually produces severe pain and tenderness of the area.
Monorchism is the state of having only one testicle within the scrotum.
Persistent Müllerian duct syndrome (PMDS) is the presence of Müllerian duct derivatives in what would be considered a genetically and otherwise physically normal male animal by typical human based standards. In humans, PMDS typically is due to an autosomal recessive congenital disorder and is considered by some to be a form of pseudohermaphroditism due to the presence of Müllerian derivatives.
Polyorchidism is the incidence of more than two testicles. It is a very rare congenital disorder, with fewer than 200 cases reported in medical literature and six cases in veterinary literature.
The paired gubernacula, also called the caudal genital ligament, are embryonic structures which begin as undifferentiated mesenchyme attaching to the caudal end of the gonads.
A colt is a male horse, usually below the age of four years.
A stallion is a male horse that has not been gelded (castrated). Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" neck, as well as a somewhat more muscular physique as compared to female horses, known as mares, and castrated males, called geldings.
Veterinary surgery is surgery performed on non-human animals by veterinarians, whereby the procedures fall into three broad categories: orthopaedics, soft tissue surgery, and neurosurgery. Advanced surgical procedures such as joint replacement, fracture repair, stabilization of cranial cruciate ligament deficiency, oncologic (cancer) surgery, herniated disc treatment, complicated gastrointestinal or urogenital procedures, kidney transplant, skin grafts, complicated wound management, and minimally invasive procedures are performed by veterinary surgeons. Most general practice veterinarians perform routine surgeries such as neuters and minor mass excisions; some also perform additional procedures.
Horse behavior is best understood from the view that horses are prey animals with a well-developed fight-or-flight response. Their first reaction to a threat is often to flee, although sometimes they stand their ground and defend themselves or their offspring in cases where flight is untenable, such as when a foal would be threatened.
Orchiectomy is a surgical procedure in which one or both testicles are removed. The surgery can be performed for various reasons:
Male genital examination is a physical examination of the genital in males to detect ailments and to assess sexual development, and is normally a component of an annual physical examination. The examination includes checking the penis, scrotum, and urethral meatus. A comprehensive assessment of the male genitals assesses the pubic hair based on Sexual Maturity Rating and the size of the testicles and penis. The exam can also be conducted to verify a person's age and biological sex. The genitourinary system can also be assessed as part of the male genital examination. During a genital examination, the doctor can detect any of the following: structural abnormalities, urethral opening abnormalities, problems related to not being circumcised, lumps, tumors, redness, excoriation, edema, lesions, swelling, cancer, hair-related issues, and many others. In some instances where a physical examination of the male genitals is not sufficient to diagnose an individual, then an internal genital examination using imaging or ultrasounds will be needed for further evaluation.
Zeuterin (zū-tur-in) is the trade name of an injectable product containing zinc gluconate and the amino acid arginine, which is used for sterilizing young male dogs without the removal of the testicles. The product is injected directly into the testicle, where the zinc gluconate destroys the sperm and causes inflammation, which leads to fibrosis and causes sterility. Sperm production continues for up to 60 days after product administration, and in some dogs does not stop completely, although the product is 99.6% effective when given to dogs aged 3-10 months of age. Following administration, the testicles atrophy; the degree of atrophy may vary noticeably between testicles. The male hormone, testosterone, is produced in limited quantities following treatment with Zeuterin, but after two years, testosterone production is similar to that in untreated dogs. The continuing presence of testosterone means that, unlike surgical castration, chemical castration does not remove the risk of testosterone-associated disease, such as prostatic disease.
