Well well well. Here we are. It's Friday. And we've been talking about SPERM ALL WEEK.
What to do...what to do...
Nel-Themaat et al. "Quality and freezing qualities of ﬁrst and second ejaculates collected from endangered Gulf Coast Native rams" Animal Reproduction Science, 2006.
So it turns out that the people who wrote the study Sci covered the other week wrote ANOTHER one. Also, it turns out the eland is not endangered, but the other species they were working with, the Gulf Coast Native Sheep, IS endangered. Though it's a rather odd beastie, in that it originally was from a population of European sheep brought over to the US, which escaped, went feral, and is now considered its own variety. This is an important sheep to look at in particular because the Gulf Coast Sheep has become adapted to living in a moist environment (as some of you may be aware, the southeast of the US is very moist, in some areas is it entirely IMPOSSIBLE to get all the mildew out of your house EVER), being less sensitive to parasites and less sensitive to fungal problems like foot rot. This means that if you wanted to, say, work with sheep in humid environments (sheep are often introduced domestically for very poor areas, and the southeastern US is apparently trying to reintroduce them. It is Sci's hope that they might eat the dang kudzu), you might want to take a look at these Gulf Coast sheep, and maybe steal of their useful genes for your benefit. And of course if you are going to steal some genes and breed some of these Gulf Coast sheep into your stock you need...some sperm.
Multiple ejaculates. Because once is never enough.
Oh and also:
For those who don't know about kudzu. It SUCKS. A lot. There's a house under there, under the lump in the middle. Really. It was introduced (I think from Japan) as something for cows and sheep and stuff to forage on. Also, it was apparently ornamental (*snort*). There was only one problem with the plant.
Cows WON'T EAT IT. I mean, they'll eat it if they're STARVING, but they don't enjoy it. Goats don't either. NO ONE DOES. And kuzdu can grow like...kudzu. In the southeast, it takes over EVERYTHING. Every spring and summer becomes a war on the kudzu. A sheep that would eat this crap would get a grateful hug from Sci every day of it's little life. It would also get VERY fat.
Anyway. Back to semen. I know what you guys REALLY want to hear about.
Sci knows she's got a good paper when the results headings are things like "Semen collection", "Semen evaluation and cryopreservation", and "Evaluation of post-thaw semen quality". In this study, the authors took some sheep, and got them off twice in a row, storing the semen in the freezer, and then checking to see how the semen kept.
Now how do you get a sheep off? Particularly one that may not be best pleased with you? Well, you knock it out first (duh). Then you electro-ejaculate it. Take some electrodes. Attach near the perineum and prostate. In the case of the sheep, that means through the rectum. *ZAP* Ejaculation!
And you do this 10 minutes apart.
You might be wondering, why on earth would anyone jack off a sheep twice in 10 minutes?! Good reason. Say you're in the wild. You're trying to helping a declining population and you need some sperm. Chances are, any animal you catch isn't going to give you a lot of time, even if you DO knock it out. You need to get it off and get it off quick, as many time as you can, for as much usable sperm as you can. Simple.
But the question is: is it the same ejaculate every time? Is one ejaculate better or worse than another?
Well we're going to look. And for us to look, I'm going to have to GRAPH. Stupid tables. A picture is worth 1000 words, authors. Pictures!!!
Here we go then.
You can see there the 1st ejaculate in dark blue and the 2nd in light blue. The volume in mL is on the left, and the sperm count on the right. It's pretty obvious (I did the stats too, it's all for a love of data) that the second ejaculate isn't as good as the first in terms of both volume and sperm count (of course the lower volume contributes to the lower sperm count).
But what was interesting was when they cooled and froze and thawed the semen. This is important, as you're going to have to get it back, possibly save it for later, and then get it into a female. So they cooled, froze, and thawed their ejaculates, and looked at sperm motility, which is a good measure of whether the sperm have got it in them (and graphed it, good little scientists):
You can see up there that the second ejaculation (in the grey bars) actually survived cooling BETTER than the first ejaculate.
The authors conclude that this means that the second ejaculate is a good idea. Sci agrees that it's a good idea, but you also have to take into account that, even though the rate of survival was better in the second ejaculate, the sheer NUMBERS were lower. So how much is it really going to help?
Sci wants to see a bigger study. I want to see second ejaculates (from different sheep or different days) at 10 min, 30 min, and an hour. What if 30 min and an hour are much better as far as second ejaculate quantity? If another 20 minutes makes a difference, Sci says it's probably worth keeping the animal out for that long. An hour...well maybe try to catch it again? 🙂
And that's your Friday Weird Science. On Monday, we're back with...what might seem to be more weird science. Get ready, and ejaculation post is coming at you (oh yes, Sci went there).
NELTHEMAAT, L., HARDING, G., CHANDLER, J., CHENEVERT, J., DAMIANI, P., FERNANDEZ, J., HUMES, P., POPE, C., & GODKE, R. (2006). Quality and freezing qualities of first and second ejaculates collected from endangered Gulf Coast Native rams Animal Reproduction Science, 95 (3-4), 251-261 DOI: 10.1016/j.anireprosci.2005.09.014