Castration of male mice

Introduction

Recently, there is complete misinformation in the mouse world about the procedure of castration of male mice. Of course you can have your own opinion on anything. However, it is worth supporting them with facts, and in the case of "mouse experts" apply that it is even necessary. Even though the opinions are based on the old and well-known "I don't know, I'll tell you." In this text, I will provide information from the perspective of a performer with over four years of bacterial culture and over three years of experience in castration of male mice.

What is the effect of current disinformation?

Firstly, limiting access to new end-users for adoptive males - because scaring people running houses limiting "large applicable death" and "complications of operation" dissuade these people from castration of males. The same often in temporary homes until death, thus blocking the place for other needy rodents for up to 2 years. They do not block the usual cages, and sometimes others, assuming that they themselves come from the example of two "kindersurprise" litters. Let's face it - having the power of possession, mice want to have a regulatory herd of 2-3 students, not one male, which, due to aggressive behavior, cannot be combined with certain other males (risk of controlled biting, including legal biting), and due to on fertility - no connection with a female (unless someone wants to die like the legendary king Popiel).

Secondly, the demonization of people who are ready to castrate their male mice and the campaign against such people. It does not matter whether castration is decided by a private person, a person and a temporary home, or offered to a mouse. “But how could you expose your student to such a huge risk of death?!?!?! You are irresponsible/irresponsible!!!”. Such opinions are unfair and untrue, which they explain in a detailed part of the text.

What is this "terrible" and "risky" procedure of castration of male mice and why is it shrouded in great mystery and horror?

Until the last, apart from laboratories, no one decided to castrate males for the necessity of performing. You write about "large scale" I have hundreds of fighters. No wonder - hardly anyone has to leave with typical modules, and if they somehow came out of them uncastrated males, a determined person who is not available to castrate them all. Unfortunately, the procedure in veterinary treatment is not the cheapest, its cost oscillates between PLN 100 and PLN 200.

In addition to other people, they decided to castrate their mouse pupils, and a few cases were confirmed as a confirmed procedure - testicular cancer, abscesses, testicles prolapsed from the scrotum (usually as a result of being bitten by another male), acquisition of a pair of sex sections was detected, inability to separate the herd of males into cages when they are subject to aggressive behavior towards each other. Treatments are not carried out and still are not used in control tools, because they usually lack knowledge and practice (insufficient education in the field of knowledge about rodents in the veterinary study program), and learning to perform this procedure is simply unprofitable: you have to have "who" the owner (which may result in higher mortality and complications, and thus - the veterinarian getting a bad opinion among rodent owners), and the number of people who applied for such an approach is a negligible consequence. Veterinarians cannot be blamed for not using the male mouse castration tool. The procedure for an experienced person is trivial, and for someone without experience with rodent surgery, performing it can surpass with a miracle.

Key male castration at a glance:

Anesthesia of the animal for the procedure - and with it is associated with the greatest risk of death during castration.
Removal of the gonads (testicles)
Depending on the mouse - with or without the administration of arousal drugs and proper veterinary care. Some mice wake up very quickly after surgery, and there is no need for such drugs

If the procedure seems so easy, why is it so difficult and risky?

The doses of anesthetic drugs given in veterinary textbooks are usually far too high. Most often, I came across the recommended dose of as much as 200mg of ketamine per kilogram of mouse body weight. The result was that out of the first 10 males subjected to castration, as many as 4 did not survive it due to an overdose of anesthesia. In practice, a dose several times lower than in the veterinary literature is a dose sufficient to anesthetize mice for the time of the castration procedure. For 2.5 years, 100% of my mice without any disease (cancer, metastatic cancer, respiratory infection) subjected to ketamine and xylazine anesthesia wake up after the procedure. Inhalation anesthesia is not required for the castration procedure. Sometimes the same dose of anesthetics used in mice from the same litter may be too much/too little for one sibling. Each animal reacts differently to medications, even when administered according to the manufacturer's instructions, which is why the experience of a veterinarian anesthetizing the animal and his observations are so important.
The dose of wake-up medication is too high. With a small dose of anesthetics, administration of wake-up drugs is usually pointless. When dosed correctly, the mouse usually wakes up 10-15 minutes after castration is complete. Excessive administration of arousal drugs (and, as with all drugs in mice, they are easily overdosed) can lead to the death of mice, possibly due to tachycardia, ventricular fibrillation, and sudden cardiac arrest. In practice, I recommend using stimulant drugs only in case of an overdose of anesthetic drugs, to reverse their effects.
Incorrect surgical technique - many can be mentioned here: too fast, too hard, inaccurate, careless. Mice are small creatures and surgical procedures on small rodents just require "something" and/or years of practice.
Incorrect aftercare. After the procedure, the mouse should be in a quiet place until it wakes up, on a heating pad (or in a special incubator), with access to oxygen, on paper towels (after which you can also notice possible bleeding from the postoperative wound, indicating periprocedural complications). She should be given a drip if deemed appropriate by the vet and an antibiotic to prevent infection in the wound. Too low temperature can lead to hypothermia, the lack of a drip can (but does not have to) prolong the recovery time, the lack of an antibiotic can lead to a scrotal abscess, and then to sepsis and death.
Difficulties in reliably assessing the health of a mouse undergoing surgery. In fact, before the procedure, each animal should be thoroughly examined physically, have blood tests, and a thorough interview with the owner should be collected. The animal must be of the right age and size to minimize the risk of complications during the procedure. Any active infection, poor blood test results, too young/too old age, too small body size (and especially testicles) are an increased risk of complications after the procedure. In addition, there are genetic predispositions to the occurrence of defects in the heart, respiratory system, hypersensitivity to anesthetics and wake-up agents - if any of the above were present in the mouse family, the risk of the procedure is higher.

Is the procedure really dangerous and high risk?

There is no definite answer and anyone who is 100% for or against does not know what they are talking about. Each mouse case should be considered individually. The animal must be thoroughly examined before each procedure, and in the case of castration, it must be completely healthy. The vet must be experienced, it is best to go to someone who has already performed many such procedures successfully. If the family health and disease history of a given mouse is known, especially their survivability of anesthesia, the veterinarian must assess the risks of anesthesia. Appropriate post-operative care must be provided after surgery.

Considering all the above facts, it is ignorant to unequivocally say that "castration is evil."

Why is it sometimes worth opting for castration? Why did I, as a breeder, decide to castrate?

In nature, mice live in large family herds, both males and females are strongly gregarious. Males tolerate their sons and brothers if there are clashes between them and one of the males with a lower position feels threatened, or simply decides to start his own herd - he has virtually unlimited possibilities to move away from the family and find his own territory, or he can move away from the dominant male enough not to provoke aggression.

By domesticating the mice, we took away their freedom to move away from the herd. This results in frequent aggression of males towards each other when kept together in too small an area (let's face it, we are not able to provide any of the rodents kept at home with the conditions that they would have in nature), bullying and biting weaker individuals, which can even lead to their death.

It is quite selfish, therefore, to keep herd animals alone, condemning them to only human company. One male will tolerate it better, not openly showing that he lacks the company of mice (in nature, he would live in a herd of females), the second will be apathetic, "very calm" for the rest of his life, which we may not interpret as pathological behavior, the third will fall into stereotypy and, for example, manic rod-biting, and the fourth, after losing the family pack (for example, after the death of a brother), will manifest depressive disorders and shortly after the death of a mouse close to him, he will fall ill or "die for no apparent reason". Of course, there are mice that will never accept the company of another mouse, regardless of gender or castration, but these are exceptions to the rule and in home conditions they can be considered pathological cases (perhaps in nature such individuals would behave differently).

What does castration give to males kept in home conditions, deprived of the opportunity to fully display their natural behavior?

Aggression towards other males in the vast majority of cases is caused by high levels of the hormone produced by the testicles - testosterone. Removal of the testicles cuts off the main source of testosterone production. In small amounts, it is also produced by the adrenal cortex, so castration will not completely stop the production of this hormone. Testosterone in males is a hormone important in development until adulthood, so it is worth waiting with castration until the mouse reaches full sexual maturity. Expectation, unfortunately, is associated with the risk that aggressive behavior towards other males will be fixed in the animal's psyche. In practice, I have come across only a few such cases, about 400 neutered males from my breeding lines (at the time of writing this text). Usually, castration of even a 1.5-year-old male completely eliminates aggressive behavior towards other males.

It is mainly testosterone that drives male mice to fight for territory, females and dominance in the herd. Testosterone is also largely responsible for the unpleasant and very intense smell of males, which rejects their adoption. Castration in most cases eliminates the male scent, it becomes comparable, and sometimes even less intense than the female scent. At home, when two testosterone-fueled males meet in a small cage, the meeting can end tragically. Let's face it, mice that are supposed to be only pets, that are never supposed to breed, such a high level of testosterone is simply not needed, and sometimes even prevents healthy functioning with other mice. So we face a choice: condemn a male to live alone without a family herd, condemn two or more males to the risk of constant quarrels and fights, and thus the possibility of biting one of them, or assess the risk of castration and allow him to live with other mice. Again, each case must be considered individually.

Why do some kennels and temporary homes decide to mass castrate male mice?

To be completely honest - largely due to space, time and finances. Most of us do not have a house made of rubber, unlimited time and financial resources. Practically in each litter a male will be born, sometimes even a dozen of them will be born. Assuming that the breeding produces 3 litters per month, it can be assumed that at least 3 males will be born, and if the breeder is unlucky, more than 30. Uncastrated males are usually very problematic in breeding. Kept in herds, they can horribly mutilate each other, sometimes even kill. Chapped tail tips, torn ears, abscesses usually on the back, and sometimes tearing of the scrotum and prolapse of the testicles are the norm. There is almost always a problem with releasing unneutered males to a new home, because practically no one wants them, even for free. A large part of non-neutered males have a very oppressive smell and sooner or later get into fights with their brothers or father, and unrelated males are not recommended at all for inexperienced and mentally unstable people to the possible consequences of mating. The need to separate aggressive males from those that live politely in the herd leads to the occupancy of breeding containers intended for mating pairs, and at some point to stopping the implementation of breeding plans mainly due to lack of space, but also increased financial outlays on food and bedding and the need to spend more time for more animals. There are few ways to get out of the stalemate of many surplus and adult males: giving males up for adoption for free (which is not so easy), giving males for food for other animals, euthanasia and disposal in a veterinary clinic, suspending breeding and keeping males to their natural death and... castration. After castration, males usually find new homes in mouse herds without any problems. Some breeders prevent "smuggling" with males by putting male pups to sleep within a few days after birth. If anyone thought that the kennel smells of violets and consists in babysitting little mice, then I am correcting the mistake. When breeding, one must be ready for the presence of death in the breeding process.

Luckily, foster homes are increasingly opting for castration for reasons similar to breeding reasons. There are a lot of mice looking for homes. Pregnant females often end up in temporary homes, and the temporary guardian decides to raise and adopt litters. We cannot cheat nature, males are still being born, and there are no more people willing to adopt them. As a result, unneutered males lock up foster homes for months, leaving other needy mice with nowhere to go. Of course, castration of mice of unknown origin carries a greater risk than castration of males from a proven breeding line. Here, however, every temporary home must ask itself a question - is it worth taking the risk and giving males more opportunities for adoption by permanent homes, or not risking and blocking space for other rodents in need.

A common reason for breeders and foster homes is awareness of the nature of mice. As I have already written, they are herd animals and only a few individuals, often on the verge of pathological behavior, will not enjoy the company of potential friends. Males, when given the opportunity, display really beautiful and elaborate herd behaviors and relationships, groom each other, dig sawdust together in search of sweets, build nests, play, and often take care of a sick individual. Mice fathers often take care of their offspring with care and often spend as much time in the nest with the young as mothers of the litter. I can't count the cases when castrati from my breeding, released to herds, fell into apathy and depressive disorders when the herd or even a single companion was missing. After more than 3 years of neutering males born to me, I would no longer decide to issue males (neutered or not) to live alone and take away their choice of life in the herd.

Why did I decide at some point in the breeding to start neutering males born to me?

I fell into the novice grower trap. I did not euthanize some of the born males right after they were born, I naively thought that they would find new homes without any problems. When the breeding started to work more dynamically, about 5 litters were born per month, after 3-4 months I had about 50 unneutered males, for whom I could not find takers, and half of them tried to kill each other. Every now and then one of the males had his tail and back severely bitten, he lost a piece of his ear. At one point, I was so desperate that I begged a veterinarian friend to perform castration, although he had no experience with anesthetizing mice. As I wrote - castration of rodents requires practice, and the guidelines in the veterinary literature do not make this procedure any easier. Unfortunately, by the time we figured out what doses of anesthetic drugs are actually safe, and not just indicated in textbooks, about 12 males out of more than 50 have died from overdoses of ketamine or wake-up drugs. In retrospect and with the amount of castrated males, do I think the loss was worth the risk? Yes. If I hadn't taken the risk, all these unneutered males would have continued to live with the stress of being bitten and dominated by the stronger ones, most of them would probably never have found homes, I would have stopped breeding, and I suspect it would be a long time before someone else desperate like me would take the risk of castrating his mouse pets. For the last 2.5 years, I do not recall losing any males as a result of castration, and several hundred males under my care have been neutered. Taking this risk allowed many males, not only those born to me, to find their herd in which they could / can carry out their social behavior. I may have encouraged the castration of some temporary homes. Thanks to this decision, I was never forced to "dispose of" unwanted males in any way. Whether it's putting them to sleep at the vet or giving them food for other animals.

Is castration of male mice just a whim of the owner?

I don't think so - I personally see very clear behavioral indications for this procedure, and why should behavioral indications be less important than medical indications?

Dear Reader, Reader. I am grateful to you if you have made it or made it this far. I hope that the information I have presented to you will allow you to make a rational and thoughtful decision about castration of your male mouse, if you are faced with such a choice. I hope that thanks to them your opinion on castration will not be only your "whim", but you will be able to base it on facts, not on coded fears or statements of people who have seen a castrated male at most in a photo on the Internet, rather than taking care of him from the beginning to the end of his life.

Text: Anna Kaźmierczyk, kennel "z Gryzakowa"
Veterinary consultation: veterinarian Martyna Dąbek
Date: 03/03/2020