Neutering

by **Eleanor** Sun Feb 09, 2014 5:25 pm

Due to the greatly mixed opinions regarding the subject of castration and spaying, the following information will be factual, rather than personally opinionated. Information and statistics on all sides of the neutering debate will be considered equally.

Neutering is the process of sterilisation of a dog, male or female, by removing its reproductive organs, either partially or entirely. It is also known as ‘fixing’, ‘de-sexing’, ‘castrating’ (male) and ‘spaying’ (female).

Female spaying involves the removal of the ovaries and/or uterus through abdominal surgery. Male castration involves the removal of the testes.

Neutering may be done for the following reasons:

Reduction of hormone levels in order to prevent or eliminate certain undesirable sexually dimorphic behaviours, such as mounting (‘humping’), testosterone-related aggression (males – often when a bitch is in heat), scent marking, etc..
Reduction of health risks, including the risks of developing mammary cancer (female), testicular cancer (male), ovarian cancer (female), prostate infections (male), pyometra (female), etc..
Elimination of reproduction.
Elimination of seasons and metrorrhagia or ‘spotting’ (female).
Elimination of false pregnancies, also known as phantom pregnancies, hysterical pregnancies and pseudopregnancies (female).
Reproductive control in rescue dogs.

Advantages and disadvantages or neutering

Advantages:

Provision of birth control.
Hormone-related sexually dimorphic behaviours reduced.
Weak evidence to suggest that neutering reduces the risk of mammary tumours and/or cancers when done before thirty months (female).
Prevention of pyometra, although stump pyometra may still develop (female).
Elimination of Uterine cancer (female).
Elimination of testicular cancer (male).
Elimination of ovarian cancer (female).
Neutering may reduce the risk of dogs being stolen for breeding purposes.
Elimination of unwanted litters (female).
Elimination of false pregnancies (female).
Elimination of metrorrhagia (female).

Disadvantages:

The risks of anaesthetic during the neutering procedure, whilst usually low in healthy dogs, may increase in dogs with pre-existing health problems.
Risk of infection, inflammation and adverse reactions to various parts of the procedure.
Increased risk of the development of hyperthyroidism.
Association with a very slightly higher risk of developing urinary tract cancers.
Evidence to suggest that early neutering may contribute to metabolism changes, with variation between breeds, possibly leading to weight gain unless counterbalanced by exercise and correct diet.
Association with increased risk of developing urethral sphincter incontinence (male).
Weak evidence to suggest that the risk of urinary incontinence increases with neutering, particularly when carried out before three months of age; risk decreases with age (female).
Evidence to suggest that early neutering (prior to five months of age) may present a higher risk of developing hip dysplasia and cranial cruciate ligament rupture.
Risk of developing osteosarcoma (bone cancer) multiplies by approximately twofold, with risk increasing with large breeds.
Risk of developing hemangiosarcoma cancer shown to be five times greater in spayed females and approximately two times greater in castrated males, according to various studies.
Increased risk of anywhere between 20% and 40% of suffering from adverse reactions to vaccines and booster vaccines, although the risk is still slight.
Evidence to show that approximately 2% of castrated dogs develop prostate cancer at some point, in comparison to the 0.6% in intact dogs (male).
Testosterone in intact dogs has been suggested to slow the development and progression of cognitive impairment conditions; studies have shown that neutered dogs have a higher risk of developing these conditions.
Progesterone, a calming hormone, is no longer produced after spaying, which has been known to escalate aggressive behaviour towards humans and other dogs (female).
Growth plates, which need exposure to testosterone and oestrogen in order to close properly; early neutering slows the closure of the growth plates, affecting the growth of the dog and possibly (un-tested theory) increases the risk of fractures later in life.
Androgenised bitches generally settle into a more feminine state after their first two or three seasons; this process is halted with early neutering, which has strongly been linked to aggressiveness and lack of social skills with other dogs and humans (female).

Misconceptions about neutering:

Bitches need to have a litter before they are spayed – there is no scientific evidence to suggest that there are any advantages to allowing a bitch to have a litter.

Allowing a bitch to have a litter will eliminate aggression – maternity for a dog is purely instinctual, rather than emotional; it is not a cure for aggression. Allowing an aggressive dog to have a litter may actually pass on aggressive qualities to the pups.

Neutering fixes all behavioural problems – actually, neutering only affects sexually dimorphic behaviour; behaviour such as mounting, territorial scent marking, territorial aggression, etc.. Many behavioural problems, such as fear aggression, will not be improved by neutering.

Neutering removes the protective instinct of a dog – the majority of a dog’s personality is formed and moulded to a greater effect by genetics and environmental factors, rather than hormones. A dog may still display protective behaviour after neutering.