Reptile & Amphibian Forums

I noticed that over the past two years, the first females in line to breed with 3 specific males had the smallest clutches compared to other females bred later in the season by the same males. Granted, it was the same females in the same order so it could just be that these snakes don't produce the largest clutches. My sample size isn't really long enough, nor were the results astounding, but here is what I was thinking...

Does anyone think that there is a possibility that the first few batches of sperm that a male snake produces in a new season are less effective/healthy then sperm cells produced after breeding season is underway and several ejaculations have taken place? I know that with many animals that breed seasonally (Horses most specifically) the first few ejaculations have low sperm counts or sperm that are frequently deformed etc. Horse breeders who use AI won't even attempt to use a stud the first few times.

I was thinking about this in terms of how long I leave my males in with the first females of the season. Usually I leave a pair together until I observe several copulations, usually no more then a few days to a week, then move the male on to a different female. If I don't see anything happen (which doesn't mean it didn't) I might give the same pair another try in a few days. This usually works well for me but this year I was thinking about leaving the first pair together longer then usual to see if that would change anything.

What do you guys think? Check your records... do you notice any similar trends or is this just a hodgepodge idea based on a coincidence?

Well, they're not quite duds if you're getting some fertile eggs but you can improve the fertility rate if you allow the male some time to generate fresh sperm before breeding. No sense using 2005 sperm cells in 2006.
I used to pull males and females out of the cooler at the same time, feed the daylights out of them and pair them off asap or after she shed, then noticed that late season breedings or those breedings that occured when the male came out a month before the female, had 100% (or almost) fertility rates.
Now I routinely pull the males out 2-4 weeks before the females and give them ample time to generate fresh sperm cells.
Did we get an R rating for this topic yet?
As far as egg size, I've seen no difference except older females tend to drop better quality eggs.
Can males be sterile? Absolutely yes.
Good luck with your breeding, Jeff

Thanks for the info. Its a good idea. I just brought my males and a few females up to temps but I think I will leave the rest of the females for another week or two like you suggest.

Also in case of any confusion from my above post, I meant that the first females dropped fewer eggs not that their eggs were any smaller or worse quality/fertility. I just felt that less motile healthy sperm would mean fewer ova get fertilized.

cheers

All sperm used in the 2006 spring breeding season were produced in late summer of 2005 and stored. That's when the wild snakes have the excess resources to devote to sperm production. On the other hand, the first sperm down the pike would also probably be the oldest.

I'd expect poor sperm to be reflected in high numbers of slugs. Good fertility rates but small numbers of eggs could be characteristic of an individual female. Or it might indicate that the female hadn't had a chance to feed well after brumation and didn't have the resources to mature a large number of ova.

It might be worth moving those females back in the roster. Then you can see if there was a change in the number of eggs that they produce and that the new early breeding females produce.

Paul Hollander