Does It Matter What Age You Neuter Your Kitten?

What science - and vets - say about early vs normal age spay/neuter for kittens.

What age should you neuter your kitten? There are several reasons for early spay/neuter as this article shows. Photo shows two cute kittens

By Zazie Todd, PhD

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What is the best age to get your kitten spayed or neutered? For most pet owners, is recommended to spay/neuter kittens by 5 months of age in order to prevent unwanted litters, according to the American Animal Hospitals Association.

There are so many cats without homes that some shelters neuter kittens early, at 8 – 12 weeks old, so they are neutered prior to adoption. This is the only way they can guarantee that a kitten will be neutered. These days, the early neutering of kittens from 6 - 14 weeks old is supported by organizations such as the American Association of Feline Practitioners (many vets set a weight limit of at least 1kg).

In the past, cats were normally neutered at 6 – 8 months old. But even kittens can have kittens, so this does not prevent unwanted litters. It comes as a surprise to many people that even a 4-month old kitten can have kittens.

Kittens, like puppies, have a sensitive period that is an important socialization opportunity; if not properly socialized during this time, they will be more fearful as adults. Therefore some people worry that early neutering could cause behaviour problems because it happens during the socialization window.

To find out, Natalie Porters et al (2014) of Ghent University in Belgium studied a sample of 800 shelter kittens. Half of the kittens were assigned to an early neutering group, and half to be spayed/neutered at the traditional age. There were approximately equal numbers of male and female kittens in each group.

The people who adopted the kittens were asked to take part in the study. They completed a daily diary for the first 30 days as a short-term follow-up, and were surveyed on several subsequent occasions up til 24 months later. 480 cats were included in the final analysis, which is a very high rate of participation from the owners.

The questionnaires asked about potentially undesirable behaviours such as inappropriate elimination, fearful behaviour, aggression, destruction, sucking on fabric, and vocalizing too much. Whether or not these behaviours are actually problematic depends on the owner’s viewpoint, so if the cat did any of these things, the owner was also asked to say if it was a problem. (Unsurprisingly, inappropriate elimination was always considered a problem).

The results are good news for shelters that want to spay/neuter kittens early: behaviour problems were not more common in cats where this was done at an early age compared to those who had the op at a more traditional age.

The short-term follow-up found that if owners reported use of physical punishment, their cats were 12 times more likely to show inappropriate elimination. In the first 30 days after adoption, if owners used verbal or physical punishment, they were also more likely to report play-related aggression, destructive behaviour and a fearful response to noises or movement.

This is in line with studies in dogs that find positive punishment is linked to behaviour problems (e.g. Herron et al 2009). However, because the data is correlational, it doesn’t tell us what the cause is. For example, it’s possible that the new kitten pees on the carpet and then gets punished; or that the kitten is punished, becomes stressed or fearful and then pees on the carpet. Perhaps people who use punishment for misdemeanours don't know how to house-train a cat, and so learning to use the litter box proceeds at a slower pace.

"if owners reported use of physical punishment, their cats were 12 times more likely to show inappropriate elimination."

Incidentally if your new kitten needs help with house-training, put them in the litter box just after eating and scratch in the litter with your finger to give them the right idea. They may need to be restricted to one room until they’ve got the hang of things. There’s an excellent chapter on litter problems in kittens and cats in Pam Johnson-Bennett’s book Think Like a Cat: How to Raise a Well-Adjusted Cat--Not a Sour Puss.

The short-term follow-up also found that cats in multi-cat households were less likely to be fearful or to be aggressive in play, and cats whose owners spent more time with them were less likely to be fearful or eliminate inappropriately. Kittens who were friendly to a stranger prior to adoption were less likely to be fearful or aggressive to family members later on.

This suggests that it’s a good idea to choose a kitten that is friendly to you, instead of shy or fearful, when you meet it for the first time.

Over the long-term, physical and verbal punishment were linked to increased destruction and more non-play-related aggression to people. However these cats were also less fearful, which may be that owners of fearful cats sensibly did not punish them. Being in a multi-cat household was linked to less destruction.

But there is a puzzling finding that when cats had 2 or 3 positive interactions with the owner during the day, they were rated as more likely to show destruction, fear or play-related aggression (e.g. attacking hands whilst playing). Is it that the owner was around more to notice these behaviours, or that from the cat’s perspective the interactions were not quite so positive? In one study, cats whose owners played with them for at least 5 minutes a day were less likely to have behaviour problems (Strickler and Shull 2014).

This is an excellent study because it involved a large number of cats and followed them up over both the short and long-term. The authors say, “from a behavioural point of view, pre-pubertal gonadectomy can be recommended for shelter cats.” An update to the study in 2018 also found no additional behaviour problems in cats that had had an early spay/neuter (Moon et al 2018).

The findings about punishment, multiple cats in the household, and time spent with the owner are all worthy of follow-up. I would love to know more about how aspects of daily life with the owner affect feline behaviour.

For tips on how to care for your kitten, check out my book Purr: The Science of Making Your Cat Happy

Is your cat spayed/neutered, and if so what age was it done?

Zazie Todd, PhD, is the award-winning author of Wag: The Science of Making Your Dog Happy and Purr: The Science of Making Your Cat Happy. She is the creator of the popular blog, Companion Animal Psychology, writes The Pawsitive Post premium newsletter, and also has a column at Psychology Today. Todd lives in Maple Ridge, BC, with her husband, one dog, and two cats. 

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References American Association of Feline Practitioners (2011) Position statement on early spay and neuter.
Herron, M., Shofer, F., & Reisner, I. (2009). Survey of the use and outcome of confrontational and non-confrontational training methods in client-owned dogs showing undesired behaviors Applied Animal Behaviour Science, 117 (1-2), 47-54 DOI: 10.1016/j.applanim.2008.12.011  
Moons, C. P., Valcke, A., Verschueren, K., Porters, N., Polis, I., & de Rooster, H. (2018). Effect of early-age gonadectomy on behavior in adopted shelter kittens—The sequel. Journal of veterinary behavior, 26, 43-47.
Porters, N., de Rooster, H., Verschueren, K., Polis, I., & Moons, C. (2014). Development of behavior in adopted shelter kittens after gonadectomy performed at an early age or at a traditional age Journal of Veterinary Behavior: Clinical Applications and Research, 9 (5), 196-206 DOI: 10.1016/j.jveb.2014.05.003  
Strickler, B., & Shull, E. (2014). An owner survey of toys, activities, and behavior problems in indoor cats Journal of Veterinary Behavior: Clinical Applications and Research, 9 (5), 207-214 DOI: 10.1016/j.jveb.2014.06.005 

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