Benefits of spaying or neutering

Why Do It?

Spaying and neutering should be the natural choice for all pet owners. Apart from population control, there is clear evidence that early neutering is better for the health of the individual animal.

When to Do It?

The latest recommendations from surgical staff at UCD are that neutering should be carried out at an earlier age than has previously been suggested.

It is now recommended that:

Both male and female cats should be neutered/spayed at 4-5 months of age
Both male and female dogs should be neutered/spayed at 5-6 months of age.

What is the Evidence for Health Benefits of Spaying or Neutering?

For female dogs spaying obviously prevents pyometra, but the effect on mammary cancer is the most significant health reason for early spaying of bitches (before their first season).

Mammary cancer is the most common type of cancer in the bitch (52% of all tumours)
Around 50% of mammary tumours are malignant
Spaying a bitch at a young age dramatically reduces the risk of mammary cancer.

Statistics showing the percentage risk of mammary tumours developing in the spayed bitch compared to the intact bitch:

Neutered prior to first oestrus: 0.05%
Neutered between first & second oestrus: 8%
Neutered after second oestrus: 26%
Neutered after 2.5 years or 4 oestrus cycles: No effect

Therefore, if a bitch is neutered before her first season, she is 2,000 times less likely to develop mammary cancer than if she is left entire until she is three years of age.

Urinary Incontinence

Urinary incontinence is more likely to occur in bitches that are spayed at any age compared to bitches that are not spayed. However, the majority of cases respond well to simple treatment, and most people agree that this risk is much less serious than the alternative risk of malignant mammary cancer.

Much research has been carried out on the effect of the timing of spaying on urinary incontinence and there are conflicting results. Some reports suggest that incontinence is less likely if bitches are spayed before their first season, while others suggest that the opposite is true.

Male Dogs

Testicular neoplasia is the second most common tumour in the male dog. As well as preventing this, early neutering also prevents prostatic disease (benign prostatic hyperplasia, prostatitis/prostatic abscesses, prostatic cysts and paraprostatic cysts). Prostatic hyperplasia starts at 1-2 years of age with 95% of dogs affected by 9 years of age.

Female Cats

Mammary cancer is the third most common form of neoplasm, though with a lower risk than in female dogs.
80% of feline mammary tumours are malignant.
Entire cats are seven times more likely to develop mammary cancer than those spayed at puberty.