Fertile After Neuter?

I was just curious about the topic, because I know there is some debate as to how long a buck is fertile after being neutered.

How is it that they can stay fertile for a month or more? I'm just curious to the biology behind it.

Thanks!

I have no idea, this is the same for boars (guinea-pigs) this is also what I would like to know.....!!?
:?

(thinking how to put this :lol I think it's because there can be little swimmers left in the plumbing - best I can explain because we have some young members :lol:

My vet said a month when I had Simba neutered but I waited 6 weeks before introducing him to Tinkerbell, just to be sure!

part of the spermatic cord [vas deferens] is not entirely removed at castration and hence sperm can be stored there for up to 6 weeks

There was a debate about this recently, I'll see if I can dig out the link!

In essence, there was an old 1920s (ish) experiment which showed that sperm remained viable for several weeks after neutering - although personally I am unconvinced by this, because the technique they were using involved tying off the tubes rather than removing the testicles. This means that the testosterone is still present, and could help to keep the sperm viable for longer.

In castration now, they totally remove the testicles so the testosterone level in the rabbit drops off a lot more quickly. So the only sperm remaining would be those in the tubes. Personally I am sceptical that this remaining sperm could live for longer than a fortnight at most, but obviously not wanting to create unnecessary babies we seem to err on the side of caution and recommend several weeks before putting a newly castrated male with an unspayed female.

Edit: here's the link to the other thread http://forums.rabbitrehome.org.uk/showthread.php?t=172985&highlight=sperm

mine was able to get my doe pregnant at 9 weeks after the op!

*lily* said:

My vet said a month when I had Simba neutered but I waited 6 weeks before introducing him to Tinkerbell, just to be sure!

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yeah six weeks sounds right Joey has been done a month but is deff still hormonal

I know somebun who escaped after his neuter 7 weeks previous and managed to 'knock up' several unspayed females. So it definitely does stick around for a fairly long time.

youngbunny2 said:

mine was able to get my doe pregnant at 9 weeks after the op!

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I have to say that I side with Santa on being a little skeptical concerning these cases where the buck is still fertile after 6 weeks or even less. Are you sure that buck was the one who got your doe pregnant? Were there any other bunnies and when did the doe give birth?

I guess the ultimate question is how long does sperm stay viable inside a rabbit who has had their testicles completely removed. 2 1/2 months seems quite long, especially considering that rabbits are meant to breed frequently and quickly, not to hold their sperm for a long time. I would assume sperm should be more about quantity here than long-term quality. But, of course, there are dangers in the assumptions I'm making.

(Also, I saw the question in the other thread asking about how it's done in the US. I can't speak for the whole country, but at least where I am around Seattle, the testicles are completely removed and the inguinal ring is shut. I think my vet mentioned tying tubes as well, but I was kind of freaking out thinking about my darling under the knife and didn't listen as well as I should have. )

I asked my vet this because I had a bit of a worry with my buck humping my 12 week old doe 19 days post castration!! She said 2 weeks is normally enough time...but if putting together wait 4 weeks!!

fionabisset said:

(thinking how to put this :lol I think it's because there can be little swimmers left in the plumbing - best I can explain because we have some young members :lol:

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:lol: Swimmers in the plumbing