It might be fair to say that female cats are more likely to feel permanently less optimistic and less calm after the spaying operation. I explore the mood effect in this article. The spaying of female domestic cats is completely accepted by people. It’s considered mandatory to prevent unwanted cats. It’s perceived as a physical alteration of the cat and veterinarians normally say that it improves the female cat’s health. It is promoted. In medical language, it is a ovariohysterectomy in which the ovaries and uterus are removed completely in order to sterilise a female cat.
“A spayed female makes an outstanding pet” (Cat Owner’s Home Veterinary Handbook). That’s the point. The operation makes female cats better for people but does it improve the life of the animal in terms of mental health or achieve the opposite? We often don’t know because we can’t get into the head of cats accurately. We guess at their mood and feelings.

Scant recognition is given to how a female cat feels in the longterm after being sprayed. There is a discussion about whether cats put on weight after being spayed or neutered (male cat castration) but it has always occurred to me that such a major operation which deprives the female cat’s body of hormones such as oestrogen and progesterone, must have an effect on the way the cat feels.
Nature, through millions of years of evolution, gave the female cat these important hormones for a good reason. For example, oestrogen in people has many roles including contributing to cognitive health, bone health, the function of the cardiovascular system and other body processes. It affects a woman’s moods. Low oestrogen levels are linked to depression, anxiety and mood swings. Oestrogen is linked to mood disruptions such as premenstrual syndrome, premenstrual dysphoric disorder and postpartum depression.

The conclusion is that in humans, oestrogen affects a woman’s moods and the way she feels. Progesterone is referred to as a calming, mood, sleep and bone enhancing hormone. These hormones are removed from the cat after the operation.
So how does the removal of these hormones from a female cat affect her? It seems to me that most websites brush aside the emotional changes as if they are minor and incidental. They say that female cats get back to normal and are healthier after the spraying operation. There is no more yowling and wild behaviour. There are no personality changes.
But why are there no personality and emotional changes in female cats after the removal of her ovaries when there are significant changes in the way a female person feels after the same operation? Female women can suffer from depression and anxiety and have memory problems after both ovaries are removed.

Perhaps people have got this wrong. There seems to be little research on how cats feel after the spraying operation. Perhaps there is no research and/or it is too difficult to try and find out. In terms of animal research on how they feel after the spraying operation you can find some studies such as those on monkeys. One website tells me that spayed monkeys ate and drank more and groomed and had sex less. Because they groomed more it indicated that they suffered from more stress than normal. The researchers believe that the presence of ovarian hormones help to keep female macaque monkeys calm and socially engaged.
With respect to tests on mice, they found that mice without ovaries often refuse to explore and they failed the sink-or-swim test. This test measures how depressed a mouse is. They force mice to swim and if they give up more quickly they are more depressed or perhaps less optimistic and committed. So once again it appears that for mice the removal of hormones produced by ovaries results in a mood which is likely to be depressed from the normal.

I’m asking questions. I’m asking them as I write this. I don’t know the answers but if you dig around and ask the questions you are driven to the conclusion that (1) people are not focusing enough on a female cat’s mood after spaying and (2) my guess is that female cats’ emotions are less good after the spraying operation than they were before it.
Female cats may be less optimistic after the ovariohysterectomy although they will be healthier and they won’t produce offspring. It’s the last objective which overrides everything else because spraying a female cat is done for the benefit of people.
P.S. the spaying operation is not a minor one. It can go wrong. People are putting a cat through a major procedure. I am not suggestion that we stop spaying cats. I wish to recognise the whole affect of the operation and for people to take responsibility for what they do and not underrate or casualise it.
P.P.S. Is it reasonable to equate the affect of hormonal removal in humans to that of cats? Yes, because the fundamental anatomy is the same.
Thanks. I support spaying and neutering but it seems a failure in the human-to-cat relationship. We can only accept modified animals.
After a great deal of soul searching – we live in a very remote area – and one unplanned pregnancy (four absolutely gorgeous kittens) we have just had our female cats spayed. I hate it. I understand all the arguments and the reality that the world as we have made it requires it, but however one dresses it up, it is a mutilation and a betrayal, to my mind. I very much appreciated your thoughtful approach and would truly love to see such mindfulness applied by vets and cat owners. It is important to realise the enormity of what we are doing instead of trying to normalise and negate it for our own convenience.
Thank you for delineating this overlooked subject so clearly.