There are absolutely intact female rabbits that live long lives without getting uterine cancer. I too get annoyed that so many veterinary clinic  web sites state varying degrees of risk (one in 25 does at age 2, 40% at age 3-4, 80% at age 6 and so on), without stating the source of this intel. It is however not a myth that uterine cancer and other reproductive tract disorders are common in intact female rabbits, but the exact numbers do seem up for some debate, and like you, I would like to actually delve into the science behind all these numbers that get thrown around.

We do see intact girl rabbits with reproductive tract disorders here, but that of course is the nature of internet forums, people tend seek out forums when they are faced with a problem of some sort. There’s no mystery about why female rabbits are prone to cancer and other reproductive tract disorders.  I quote: “Evolution has equipped rabbits with the capacity to breed fantastically fast, but in doing so, the female reproductive tract is so “overactive” that the uterine wall undergoes metaplasia (cells changing form) and then neoplasia (formation of tumours). The most common (unquote cancer form unquote) is an aggressively malignant uterine adenocarcinoma.” https://vethelpdirect.com/pet-health-library/rabbit-uterine-tumours/

I’m glad your bun is happy 🙂 It is a good sign. One of the early signs of reproductive tract disorder can be that the bun develops grumpiness and aggression. This can be due to high levels of sex hormones circulating in the bloodstream, or to discomfort/pain. If you notice that, do take her in for vet assessment.

Sadly many rabbits show no early signs of something being wrong until cancer has already formed,but mood changes is definitely something to be aware of.

I would still recommend desexing girl rabbits, but it’s always up to the owner to decide what is best for the individual bun.

Hi @Harps

I second all that Bam said. 🙂 It is great how she is behaving well for you, shows a sweet bun. 😉 My girls were sweet before too. I had all three of my ladies happily bonded, they showed not the slightest bit aggression, they were all the cuddliest buns you could ever ask for. 😀 Until one day, I had to separate them all, for hormones hit hard. I noticed little things from them, chasing, nipping, humping was most common. I knew that mounting was common for rabbits, so it didn’t worry me too much as first, but, ah, it continued to go worse, so I separated them. 🙁

When they were all separated, they each had at least one false pregnancy. Silver had three, OB had two, and Smokey had one. They were so stressed out, and my heart just cried for them, so I had them spayed as soon as possible. 🙂 Now they are going through the bonding process, and are the sweetest buns you could ever ask for. 😀

I do not mean at all to come across as aggressive, I just want to share my story and thoughts in the hopes that they will help you or someone else reading this. 🙂 I think that your girl is living a very spoiled life, and she sure is cute! 😉 Again, I’m happy she’s happy, she reminds me of my Smokey. Smokey is the most optimistic bun of them all. 🙂  Wishing you the best of luck, and easy thinking! 🙂

I agree with Bam and HipHop and would very much advice you to get her spayed anyway to prevent reproductive cancer.

Also, you might want to reconsider letting her run loose in the park. It’s great that you’re trying to provide her with that outside playtime and stimulation. However, if this is a public park, you don’t know if someone is going to let their dog run wild, birds of prey could grab her, so many things could go wrong and with your bun running around off leash you have no control whatsoever. If something does happen it will be too late for you to interfere or pick her up. Public parks usually get sprayed with pesticides as well, which would be bad for your bun. Picking up diseases or parasites (especially from other animal’s droppings) is a concern as well. Personally, I wouldn’t take her to a public park at all, but at the very least I think you should use an x-pen with a cover to keep her as safe as possible.

I have seen the actual published studies, I am trying to find them again now for everyone’s reference. It is certainly not a myth and the numbers are not inflated. Rates of cancer go up with age, and vary by breed. So the lifetime cumulative risk is quite high (that’s that 80% number you’ll see), but people might choose to quote one age or another.

On a personal level, a 6 year old unspayed bun just came into the shelter with metastatic uterine cancer. The vet hopes they removed it all, but there you go. My female bun growing up that was unspayed died at 7, while her brother lived to be 9 or 10. Of course we can’t say why, but I suspect uterine cancer was likely the cause since their care was identical and they were related.

How old is your bun?

Ok, I re-found the long term study that is where people get the numbers most often quoted (short term studies are misleading, since most lab and meat rabbits don’t live long enough to get cancer):

http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC2032762&blobtype=pdf

“Thirty-seven percent of tumor-bearing animals had second primary tumors elsewhere. Ingalls et al discovered 353 uterine tumors among 1735 rabbits of the Phipps colony, which was observed for 30 years. The incidence of tumors increased with age, reaching approximately 60% in animals over 4 years of age, in both colonies cited, and 79% in Greene’s colony of 5-year-old animals.”

Here are some additional references that talk more about pathology etc. Let me know if you can’t access and I can send you pdfs. There is really a lot of research on this so this is just a selected few.

Baum, B., & Hewicker-Trautwein, M. (2015). Classification and epidemiology of mammary tumours in pet rabbits (Oryctolagus cuniculus). Journal of comparative pathology, 152(4), 291-298.

do Carmo Silva, H., de Oliveira, A. R., dos Santos Horta, R., Moereira, B. S., Silveira, T. L., Cassali, G. D., & Dantas, M. C. (2019). Mammary gland malignant myoepithelioma in a domestic rabbit (Oryctolagus cuniculus). Acta Scientiae Veterinariae, 47.

SAITO, K., NAKANISHI, M., & HASEGAWA, A. (2002). Uterine disorders diagnosed by ventrotomy in 47 rabbits. Journal of Veterinary Medical Science, 64(6), 495-497.