Neutering You Cat: Dealing with Increased Appetite Caused by Sterilisation

Being a pet owner brings responsibilities as well as privileges. One of the most important responsibilities is making education decisions about what is best for your pet.

For most cat owners, sterilisation (neutering) is one of these educated decisions. In fact around 90% of cats in the UK are neutered (Murray, 2009).

The reason sterilisation is so popular within the UK cat population is due to the desirable behavioural changes and the improvement in health that comes with neutering. However, neutering is not without its problems.

Why and When to Neuter Your Cat

Cats reach sexually maturity at around 5 – 8 months of age. Upon reaching sexual maturity, cats start to exhibit new sexual behaviours, such as increased territorial behaviour, aggression in males and ‘calling’ behaviour in females.

At sexual maturity, it becomes possible for females to conceive. Due to the relatively free roaming lifestyle of cats (compared to dogs for instance), the short gestation period and frequent fertility cycles, an unneutered female can quite easily give birth to multiple litters in a lifetime.

For the majority of cat owners, there is no interest in breeding and therefore a pregnant queen can bring with it a number of problems, most obviously, finding a home for all the new kittens!

With this in mind, it is quite easy to see why owners would want to consider spaying their female cats. It is also why responsible owners of male cats should have them neutered (castrated). However, there are two more primary reasons as to why sterilisation is a good idea:

  • Reduce Sexual Behaviour – Neutering involves the removal of male or female sex organs (such as the ovaries or testes). Their removal decreases the amount of sex-related hormones, which are largely responsible for behaviour such as aggression and ‘calling’.
  • Decrease the Risk of Diseases – Uterine infections, mammary tummors and other genital tract disease or infections are more likely in an intact cat (and dogs too!). Neutering reduces the risk of these disease leading to a longer, healthier life for your pet.

Problems Associated with Neutering

The main problems people have with neutering are the cost, welfare issues and the possibility of weight gain post operation.

In terms of cost, it is financially more economic to spay your female than pay the vet fees associated with possible multiple pregnancies as well as the costs associated with raising a litter of kittens! Castrating your male cat is also cheaper than multiple visits to the vet due to injuries sustained as a result of aggression.

Essentially there are no welfare issues, in fact, there are probably more welfare issues associated with not neutering your cat. The operation is done under anaesthesia and the large majority of cats recover from the operation quickly.

The final point, weight gain, is somewhat justified. After the operation, there is a tendency for cats to put on weight. A study found that the risk of obesity is actually tripled (Scarlett, 1998)!

Sterilisation and Obesity

As mentioned earlier, sterilisation involves the removal of hormone producing sex organs. Certain hormones produced by the sex organs have a role in the regulation of appetite, the removal of these hormones therefore reduces the ability of the neutered individual to regulate their appetite appropriately.

Typically, the castrated male or spayed female requires less energy than the intact male or female, however, instead of consuming less food, the neutered cats are actually inclined to eat more!

Decreased energy demand, coupled with increased appetite is almost certain to result in unwanted weight gain. Obesity is a serious medical condition, primarily due to the extra strain put on the body by the additional weight. Obesity can increase the risk of heart disease, joint damage, diabetes and numerous other health issues.

With this in mind, it is important that we control the neutered cat’s diet. Fortunately, sterilisation specific diets, such as Royal Canin’s Sterilised Appetite Control make this an easier task than it might sound!

A Feline Sterilisation Diet

Raising a perfectly healthy sterilised cat is more than possible with regulation of the diet. However specific diets can make the task at hand a little easier. So what makes a sterilisation specific diet different to a normal diet?:

  • Age specific selection of diets, catering from the recently neutered (5 – 8 months) to the geriatric neutered cat
  • Reduced energy density, meaning fewer calories per serving, helping to maintain an optimal body weight
  • High quality protein and L-Carnitine, both of which help to reduce the deposition of fat tissue and increase lean muscle mass
  • Complex fibre content to ensure that each serving leaves the appetite satisfied

Murray JK, Roberts M A,Whitmarsh A, Gruffydd-Jones TJ. Survey of the characteristics of cats owned by households in the UK and factors affecting their neutered status. Vet Rec. 2009Jan 31;164(5):137-41.

Scarlett JM and Donoghue S. Associations between body condition and disease in cats. J Am Vet Med Assoc1998. 212 (11), 1725-1731

About James Watts

BSc Bioveterinary Science. Editor of PetSci. When I'm not writing, learning, discussing, or reading about animals, you know it's the weekend! Currently developing PetSci HealthTrak, the fast and easy way to monitor your pet's weight and calorie intake. HealthTrak offers a simple way to track your pet's progress, helping them achieve a healthy weight and a long, happy life.

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  1. Hairless Cat Girl

    Hi James,

    Cats do reach physical maturity at an early age, you’re right.

    And you’re also right that the male aggression can lead to emergency vet visits. I’ve seen it on more than one occasion outside of my own household. Males get territorial and restless. That creates a tendency to cause fights.

    The females can have a litter at a very young age and it can be a bit hard on their health. There can also be birth defects if she gets pregnant just after reaching sexual maturity. Population explosion is another problem.

    Good point on overcoming objections to getting spayed – pregnancies do cost more than a single spay. Likewise with neutering – injuries can be costly to treat.

    Looks like you have quite a few solid arguments in favor of spaying and neutering.

    Well done James,

    =^-^= Hairless Cat Girl =^-^=

  2. Can the cat adjust to a reduced diet or does the lack of appetite regulation persist?

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