There are various reasons for spaying or castrating your Bitch/Dog ( or cat for that matter) but the obvious one must be to prevent pregnancies and thus, unwanted puppies. Below is a brief outline - professional Veterinary
Advice should always be sought

The Testis has two major functions - gametogenesis, the production of sperm and steroidogenesis, the production of hormones.
Sperm is produced in the seminiferous tubules. One of the hormones comes from the cells of Leydig which pack between the tubules. They produce Testosterone which is a hormone responsible for the development and maintenance of the reproductive tract and the accessory sex glands and for the secondary sex characters and sexual behaviour characteristic.

The ovary also has two functions - the production of ova (eggs) and the production of hormones.
Two hormones are produced - Oestradiol and progesterone
Castration (Dog)
Castration is the removal of the testicles (Testes) which is performed to prevent breeding, roaming, spraying (tomcats ) and sometimes to treat an over active sex drive (libido) or inter male aggression.
Some less common reasons are for treatment of testicular tumours, or to remove the source of hormones that stimulate certain disorders of the prostate gland and anal adenoma.

It may also be necessary to fully castrate monorchid dogs (having only one testicle in the scrotum). Veterinary advice should be sought in that instance.

This operation is the removal of the ovaries and uterus - its’ proper name being ovariohysterectomy.

The operation will render the bitch incapable of becoming pregnant. It will prevent both oestrrus (having a season) and the possible future development of *pyometra*.
Spaying is best undertaken after the bitches first oestrus and mid way between her second when her hormone levels are at a level to ensure the bitches maturation.
They should not be spayed during an oestrus or if heavily pregnant. It is also advisable not to spay during a false pregnancy.

This is a life threatening condition which requires immediate veterinary attention.
It cause is as a result of sterile or infected secretions within the uterus.
It usually occurs in the older bitch (or queen) who have never had a litter but who have just been in oestrus. Although it can occur after the birth of a litter (retained placenta causing infection)
Symptoms include frequent depression, vomiting and polydipsia (Excessive thirst). There may be a vaginal discharge - open pyometra, or the cervix may be closed - closed pyometra.

Both conditions require emergency intensive care and ovariohysterectomy.

If you are a new Boxer owner or the owner of another Deep Chested breed i.e. Great Dane, Blood Hound, and are planning to spay or castrate your pet then you need to visit this page Acepromazine

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The incision is made in the
middle, lower abdomen.

The abdomen is entered

The uterus is located and brought
through the incision.

The body of the uterus below the uterine horns is isolated and a number of sutures are placed around the blood vessels and the uterus itself.

The tissue beneath the skin and above the abdominal wall are sutured so that these subcutaneous sutures are buried beneath the skin. No external sutures are needed

Close-up view of a dog ovary.

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