Rodent Desexing

Desexing Mice and Rats

Most people think of desexing as a means of controlling pet over-population. This is equally true of mice & rats, but there are also significant health issues to consider with regards to rodent desexing.

Female rats, in particular, are very prone to mammary and uterine cancer. The first of these is far more common and fortunately the cancer is usually benign. However the cancers can become incredibly large – so much so that we often refer to curative surgery as “removing a rat from a lump”! The rat on the left has just been anaesthetised prior to the first of two surgeries to remove multiple mammary tumours. Although both operations were successful, they could have been prevented by desexing.

Uterine cancers, while less common, are a different matter. They are usually malignant and very advanced by the time they show themselves as blood in the urine and a bloody discharge from the vulva.

Male rats and mice can become quite aggressive to other animals if there is a female rat present, and for this reason desexing is recommended to prevent or curb the aggression.

Desexing is usually performed at 4-6 weeks, before sexual activity begins and before the animal becomes fat.

Males are castrated – i.e. both testicles are completely removed through an incision over each testicle. The inguinal canal – the hole in the abdominal muscles where the spermatic cord goes down to the scrotum – has to be closed to prevent post-operative hernias.

Female rats have their ovaries and uterus removed completely through a small incision near the umbilicus. We normally do not desex female mice because of their small size.

Both rats and mice frequently chew at their stitches after the surgery, but we can minimise this through the use of painkillers. Your pet will be given painkillers before and after the surgery, and sent home (usually the same day) with more painkillers for you to give over the next few days.

Desexing rats and mice is an effective means of preventing health and behavioural problems. The West Toowoomba Vet Surgery is experienced in this procedure, and strongly recommends it. To make an appointment, simple ring the Surgery on (07) 4636 2027. Remember, because they cannot vomit, it is not necessary (and sometimes dangerous) to fast rats and mice before surgery.