Why neuter (castrate/spay)?

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

When should you neuter?

The latest recommendations are that spaying and neutering should be carried out in most cases at an earlier age than has previously been suggested. It is now recommended that:

• Both male and female cats should be neutered/spayed at four months of age. This is earlier than has previously been recommended, but it is now the expert international recommendation (see http://www.thecatgroup.org.uk/)

• Both male and female small dogs should be neutered/spayed at 5-6 months of age - i.e. before a female dog’s first season/heat.

• Some animal rescue groups are spaying juvenile animals at even earlier ages for practical and cost-saving reasons.

• Both male and female large breed dogs should be spayed/neutered at approximately 9 months of age (after a female dog’s first season) to ensure these larger breeds are more skeletally mature - e.g. Old English Sheep Dog, Doberman,

Weimaraner, Springer Spaniel, Rottweiler, Irish Setter, Golden Retriever etc.

• It is currently believed it is beneficial to delay neutering/spaying male and female giant breed dogs until at least one year of age - i.e. after a female dog has had at least one season. Again, this allows them to be more skeletally mature

before neutering and may help to reduce the likelihood of osteosarcoma in these breeds.

• All bitches should have a pre-op check prior to neutering. It is not recommended to spay bitches when in season or while they are lactating. Ideally, if a bitch has had a season, neutering should be performed 10-12 weeks after the end

of the last season to reduce the risk of post-spaying false pregnancy. If a bitch has had a litter, it is generally safe to spay about 10 weeks post whelping. Neutering may also be delayed by medical issues such as juvenile vaginitis or a history of urinary incontinence.

The above suggestions are guidelines only. Every animal should be assessed as an individual and the pros and cons of neutering must be weighed up in every case with a risk-benefit analysis tailored to the individual cat or dog - e.g. social issues, convenience, dogs coming into season etc.

The Latest Facts about Spaying and Neutering

Is there evidence of any adverse effects of spaying or neutering in dogs?

• While it is true that castration is associated with an increased risk of bladder and prostate cancer, the incidence of these cancers remains very low compared with testicular cancer and other prostatic diseases in entire dogs.

• Spayed and neutered animals are more likely to become obese (changes in the sex hormone levels after neutering may slow down the animal’s metabolism), but this can be easily prevented or treated by following sensible nutritional advice.

• There is recent evidence that spaying and neutering before skeletal maturity increases the risk of bone tumours (osteosarcoma) in large and giant breeds of dog, a factor which should be taken into account when advising owners of these types of animals.

• A recent on-line paper has suggested that Golden Retrievers neutered before 1 year of age are slightly more prone to certain diseases than their non-neutered counterparts, e.g. hip dysplasia, cranial cruciate ligament tear, lymphosarcoma,

haemangiosarcoma and mast cell tumour. However, the number of dogs analysed in the study was small, and the study was limited to patients at a referral hospital only, so it is difficult to know if these results could be extrapolated to the general population. The issue of causality is also a problem in this study e.g. did neutering cause hip dysplasia in these dogs, or were the dogs neutered at an early age because they showed evidence of poor confirmation and gait, while animals with sound gait may have been kept entire for the purpose of breeding? Thirdly, the incidence of many of these diseases increases with age and in this study, most of the neutered animals were older than their entire counterparts, e.g. haemangiosarcoma is much more common in dogs aged 7 or over, compared to dogs of only 2-3 years of age.

• Urinary incontinence is more likely to occur in bitches that are spayed at any age (4-20%) compared with bitches that

are not spayed (0.3%) and can occur soon after a spay or after a delay of several years. Urinary incontinence is commonly called ‘spay incontinence’ and is caused by urethral sphincter incompetence. However, the evidence for a causal relationship between spaying and urinary incontinence is weak, although there is some evidence that the risk of urinary incontinence may decrease as age at spay increases up to 12 months of age, after which, there is no evidence of an effect of age at spay. 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. There is still debate over whether spaying before the first season marginally increases or decreases the risk of this problem.

• Some studies have made tentative links between neutering and cardiac haemangiosarcoma, hypothyroidism, progressive

geriatric impairment, urinary tract cancers, orthopaedic disorders, adverse vaccine reactions, splenic haemangiosarcoma, recurring urinary tract infections, urinary tract tumours recessed vulva, vaginal dermatitis and vaginitis if spayed before puberty. However many of these studies had skewed study populations, did not have a substantial study population size and are relatively old studies, so further studies would be required to substantiate them.

Is it controversial to recommend spaying & neutering as a general policy?

• The driving force behind the SpayAware campaign is to tackle the massive pet overpopulation problem in this country.

Vets have an important role to play in challenging Ireland’s established “non-neutering” culture. If we can generate the widespread understanding that neutering is normal, then we stand a greater chance of getting this message to those whom we do not currently find it easy to reach. An ambiguous approach on this issue breeds confusion. If we take a “maybe” stance that openly invites choice, then the choice that will most readily be made is the one that involves taking the least action and spending the least money. As a result, many bitches and dogs will remain entire and countless further unwanted puppies and kittens will be born and subsequently destroyed. It is the opinion of the SpayAware team that there are issues for discussion with concerned clients who wish to understand the risks of neutering and to weigh them against the benefits. Debate should be welcomed: spaying or neutering may not be the most appropriate decision in all cases.

• In recent years new methods of data collection and computerised analysis, together with increased research in this area,

has greatly increased our knowledge of the effects of interventions such as spaying/neutering. Hopefully with time, any uncertainty pertaining to neutering will be resolved. For example, a current UK study is looking into the effects which early neutering may have on dog behaviour, so we can look forward to learning more about this complex issue over the next couple of years.

Spayaware Campaign.pdf (size 628.2 KB)

Dog Spayaware Poster.pdf (size 395.2 KB)

Dog Question & Answer.pdf (size 314.8 KB)

Cat Spayaware Poster.pdf (size 307.6 KB)

Cat Questions & Answers.pdf (size 587.6 KB)