Back to Basics - Vasectomised Hobs - Can They Cut It?

June with Bracken 10kb Disturbing news has come to light on the subject of vasectomised hobs, writes Dr June McNicholas. Firstly, it seems that there is sometimes a little confusion about the differences between a vasectomised hob and a castrated hob and what this means for an owner and any other ferrets in the family. Secondly, it may be that using a vasectomised hob on an in-season jill is not a totally reliable method of avoiding unwanted litters, as a number of readers have reported this spring.

A vasectomy in a male ferret involves the severing of the ducts that transport the fertile sperm from the testicles to the penis. The ferret will still, technically, be fertile in that he is producing viable sperm. The only difference is that the sperm does not reach the penis and so mating a jill should not result in pregnancy. The hob will look, smell and behave as if he is an entire, sexually active, male. He may be aggressive to other males and he probably have a fairly pungent pong. He will be willing and able to mate with jills, despite the fact taht he cannot impregnate them.

Castration involves the removal of the testes and thus the production of the sex hormones. A castrated hob becomes sexually inactive, uninterested in jills, and loses most, if not all, of the inter-male aggression associated with rivalry for mating jills. He is incapable of making a jill pregnant. Lack of sex hormones also leads to less smell, a cleaner coat and a ferret who is more sociable and playful. Castration does not reduce working ability.

Until recently, vets were more accustomed to being asked for a hob to be vasectomised than castrated. It has been long recognised that jills need to be brought out of season to avoid the risk of aplastic anaemia, a potentially fatal condition. Since it is the act of mating that brings about ovulation in the jill, a mating with a vasectomised hob ends her season but does not result in pregnancy. The jill may go through a phantom pregnancy and six weeks later (the end of normal pregnancy) will usually come back into season and need to be mated again to the vasectomised hob.

Problems can occur when an owner simply asks for a hob ferret to be 'neutered'. The owner may want the ferret to be castrated, the vet may assume it is in for vasectomy. Mistakes like this shouldn't happen but it has been known. Several rescues have reported owners coming in to find companions for their 'neutered hob' only to find that it is a sex mad vasectomised hob with a lot more than a platonic friendship on its mind!

In most cases, a hob is vasectomised to bring jills out of season. Many ferret welfare organisations recommend this as an alternative to a jill jab or a permanent spay (ovariohysterectomy) operation on the jill. But many vasectomies can and do reverse themselves.

This year, I have had five incidents reported of vasectomised hobs apparently becoming fertile. Two have been in Scotland, one in the North of England, one in the South East and one in the Midlands. All resulted in unwanted litters. In two cases, the hob was lent out resulting in even more unplanned litters. Aside from the fact that every year there are too many ferrets and too few caring homes, there is the embarrassment of rescues who advise the use of a vasectomised hob and then find that they are indirectly responsible for dozens of unplanned kits.

Alarmingly, vasectomy reversal is more common than many people realise. After speaking to a number of rescues and vets, some feel the reversal rate may be as high as 70% in the two years following vasectomy. Although we have no hard statistics as yet, it offers some indications of the number of unplanned kits born each year as a result.

Why does it happen? One vet suggested that while the surgical procedure is, technically, quite uncomplicated it is often difficult to ensure that the sperm ducts are cut and tied adequately to be permanent. You are talking about tiny, tiny, pieces of tissue. Some will regrow enough to rejoin, and so the hob is again entire. Even if only one sperm duct rejoins, 'firing on one cylinder' is enough to make a jill pregnant.

The safest and most permanent thing to do is to have your jill spayed. If your vet is reluctant or quotes a price higher than, say, that charged for spaying a cat, contact your local ferret club, the NFWS or me and we will try to find you a vet who routinely spays jills at a reasonable rate.

A jill jab is another option. This is a hormone injection to suppress the jill's season, usually for the whole summer. The price varies widely, from a pound or two per jill to over 10. Some clubs have arrangements to reduce the cost. A word or advice though. Some people (including myself) have had some odd reations in jills after a jab. Some lose coats, others seem lethargic, others just are generally 'off' for a while. This may be down to the dose of hormone being a little too generous. The standard dose of Proligesterone is 0.5ml per kg and many owners and vets simply register this as a dose. However, there are lots of jills who weigh a good deal less than a kilogram so it is worth weighing your jill and asking your vet to adjust the dose pro-rata to her weight.

So are vasectomised hobs a waste of time? No, I don't think so, but we have been a bit too complacent in believing them totally reliable. Do not allow a newly vasectomised hob near jills for at least six weeks after the op. There is likely to be enough residual sperm in his interior plumbing to make a jill pregnant. He will be highly likely to be effective for his first year. It is from the second year onwards that we start to get reports of vasectomy reversals. A possibly safeguard is to limit the use of a hob until you are sure he is not fertile that year. This may mean not lending him out to other people or using him on just one of your jills at first. If this means paying out for a couple of jill jabs for others in season look on it as insurance cover. It cost more to rear unplanned litter for 6-8 weeks than it does to pay for a couple of jill jabs.

If any of you have had experience of unplanned litter as a result of putting your jills to a vasectomised hob please let me know. I, and the NFWS, are interested in compiling reports to try to identify how, why and when reversals are most likely to occur. In this way, we may be able to help to avoid future accidents.

(From Ferrets First Issue no. 19 - August/September 2004)

Articles from Ferrets First