Neutering

There are several reasons to neuter male rodents. At first there are aggressive or already seperated bucks, such as those of fancy mice, but also males of some exotic rodents would fight without being neutered.
Neutered bucks can be kept togehter with females without a population explosion you would have to fear keeping unneutered bucks with females.
But there are also some medical indications for neutering. That might be a testicular rotation or cancerous mutations of the testicles for example. Then the vet sometimes decides for an operation.
Some people have their bucks neutered, especially those of fancy mice, because of the odor. This as the only reason is not acceptable, since neutering is a large, changing surgery for the buck.

Mice are usually very small, lightweight animals. This makes the surgery more difficult than that of larger animals, since among other things the anesthesia is difficult to dose. So take care to choose an experienced vet who often does this operation on such small animals. Let the buck give an inhalation anesthesia as far as this is possible, because this tolerated better. The vet should advise you about the operation. You can also ask him/her about his/her experience and his/her successes. Choosing the right vet and the proper anesthesia is crucial for the life of your buck!
Debilitated, very young, very old and obese animals and rodents with some deformations have a significantly increased risk of dying of anesthesia.
Please note: The compatibility of anesthesia gas is not the same for all species! Therefore here is a short list of species which had already been anesthetised successfully at a vet:

• acacia rats (are very deep in anesthesia, meter it carfully!)
• bushy-tailed gerbils
• cotton rat
• deer mouse
• fancy mouse
• fat-tailed gerbil
• four-striped grass mouse
• Indian gerbil
• Mongolian jird
• natal rat
• pale gerbil
• Shaw's jird
• Sinai spiny mouse
• steppe lemming (very sensitive, dose carefully, aim on a short anasthesia)
• striped grass mouse

Usually only male rodents are neutered, since for this surgery female rodents are too small and the operation is too dangerous. Whereas neutering of males just means an surgical intervention at the scrotum, to sterilize a female means, that the vet needs to open the abdominal cavity, a much more complicated procedure.
For fancy mice the follwoing applies: The buck should be at least 12 weeks old and weigh between 30 and 50g. The age for neutering is limited up to 12 to 14 months.
For other rodents the following rule of thumb applies: The rodents shouldn't be older than half to two thirds of the average life span of the species and it shouldn't have a significant over- or underweight.

The costs depend on the vet, the form of anesthesia and the region where you live. They range from about 20 Euros up to 60 Euros and more.

Unlike many other mammals mice cannot vomit. So they can and should eat until short before the surgery. This is also important for the rapid metabolism of the small rodents to reduce the risk of hypoglycaemia, dehydration or similar complications to a minimum. Take the buck to the vet with its used bedding, feed, water (in form of cucumber or a water dish, etc.) and a house in the transport box. Thus, the buck still has a familiar surroundings and is stressed lesser than with new, unknown things around.
If you take shy exotic rodents to the vet, brief him/her how to deal with the animals the right way. Putting a gas bell on the whole rodent to anesthetise it has proved best for such shy patients. This will avoid stress of catching and fixing for both: the vet and the patient. Above that, it reduces the risk of unintended injuries. Moreover this minimizes the risk that the buck escapes and runs all across surgery.
For tame individuals the vet may also inject a mild anesthetic, so that the patient won't experience a special phase of the anesthesia consciously that is connected to fear.

During the operation, the buck is fixed on the back and the vet cuts a small hole into the scrotum. Then the adipose tissue surounding the gonads and the testes themselves are removed. Afterwards the ends of the spermatic cords are closed by a thread. Concluding the wound is closed by stitching it up or spraying a band-aid on it. Which is used depends usually on the size of the wound.
The buck usually gets an antibiotic after the operation to prevent it from infections.

After the operation, the bedding is removed from the box and replaced by kitchen roll to reduce the risk of an infection of the wound. The vet or a veterinary nurse watches the buck while waking up. Never take still sleeping mice home! During the waking up complications such as circulatory collapse may occur. Then a vet should be in reach to help immidiately. So take only fully awoken mice with you home.
During the operation, the animal begins to cool, which also persists after the surgery. Therefore it should be also warmed after the operation. Control the body temperature and make sure that the buck won't cool on the way home or during the first hours at home by using an external heat source.
The buck can and should be eat and drink right after waking up.
Leave the buck at home in a cage for some day that is prepared with kitchen roll. When the wound is closed completely you can offer normal bedding again.
In general the threads needn't be removed. Either the vet uses resolutive threads (usually purple) or the buck himself removes it after some days.

Never take an unneutered buck from his group, if not urgently necessary. His friends usually won't chew at the wound. Always take the whole group to the vet especially when they are uneasy, even though only some members are to be neutered. The patient(s) should only be separeted from the groups for the surgery and the waking up.
If you want to introduce neutered males to females, you'll have to wait for at least 3 weeks because the males are still fertile just after the operation.
The introduction of neutered males with neutered males or of neutered males with unneutered ones is much more problematic than an introduction with females. More about it you can find out HERE.
Please note: Recently neutered males, which live together in a group, may be noticably more aggressive for 14 days after the operation. Aggressions might be more frequent and more intense than before. Then the group will calm down according to the slowly reducing hormone level.