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 15th century Ottoman medical illustration by Sabuncuoğlu Şerafeddin depicting an operation for castration
The Castration of Uranus: fresco by Vasari & Cristofano Gherardi (c. 1560, Sala di Cosimo I, Palazzo Vecchio, Florence)
The procedure of castration as punishment during the 16th century
An Italian soldier who was castrated and emasculated during the Second Italo-Ethiopian War.
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.
Feline uterus
Closed spaying incision on a female dog, taken 24 hours after surgery
Surgical incision site of a female cat
Closed castration incision on a male dog, taken 12 hours after surgery