[SallyintNorth]

When I arrived here in North Cornwall in October, we had a lot of grass everywhere.  (My lot must have thought they'd come to Heaven, I think! )

Anyways, as the month wore on and we were thinking about lambing, Margot started to suggest which field we might use for tupping.  We were going to tup 11 - 4 Zwartbles and 7 fleece girls. 

She suggested one area which had been clear of stock for some months and had a good thick covering of lush green grass.  "How many triplets are you wanting?", I asked.  So we tupped in a field that wasn't bare, but which had had sheep on it for a wee while.  After tupping we made sure they had good grass, salt and minerals, hay when the grass flagged, and so on, to give them the best chance of doing well with whatever embryos were by then growing in them.  Praise be, all the Zwarts had twins .  Two of the fleece girls had triplets  (but I'd said that all mine were being flushed simply by being in Cornwall instead of Cumbria!). Quincy the black Wensleydale had a single again - I think perhaps she's one who does that, though.  (She produces and rears one cracking lamb; this year's is called Bumper  ). So 23 lambs from our 11 sheep.

Anyway, my thinking is that most ewes these days seems to produce two eggs unless things are really hard, so flushing just increases the prevalence of triplets.  As long as the sheep are very well cared for from immediately after they're tupped, so that both eggs implant and grow, I shall continue to actively not flush at/before tupping.

[landroverroy]

 I would tend to agree there.
Many years ago, when new to sheep and well read up on how essential flushing was, I read that adding zinc to the diet increases the number of eggs produced. So I gave my ewes a high zinc feed block at tupping time. Result - far too many triplets. So now they just go on good grass and a standard feed block and the triplet count is only 1 or 2 sets a year.

[Marches Farmer]

I aim to keep my ewes at the correct score for their breed all year round.  The Southdowns sometimes start and end their productive life with singles but produce twins for most of it.  The Badger Face have produced mostly twins this year, more than usual but that may be down to the tup.  I had a SD bloodline that regularly produced triplets but culled it out.  I prefer the ewes to do the work from the start, rather than faff around with adopting onto singles and possibly bottle feeding.

[landroverroy]

.  The Badger Face have produced mostly twins this year, more than usual but that may be down to the tup..

Multiple births are governed by the number of eggs produced by the ewe. The tup should produce  millions of sperm, but if there's only one egg from the ewe, then you can only get one lamb! So it doesn't matter how persistent your tup is - he can't fertilise eggs that aren't there.

[Marches Farmer]

But if he has top quality sperm and his timing is spot on more of the little chaps might make it to the eggs ....

[landroverroy]

You don't need masses of the little chaps to get there - just one/egg is all it takes!
And it's fairly irrelevant how many of his top quality sperm make it if the ewe has only produced one egg.

[SallyintNorth]

I have long wondered whether there could be something to do with how eggs implant that's affected by the sperm, possibly mitochondrial DNA or something, which would account for the apparent difference in hit rate of some tups.

I'm sure that biologicallly speaking it's possible, but not aware of any research into it.

[landroverroy]

Can't say I've ever noticed any particular difference with different tups. I've seen more difference due to yearly variations in quality and abundance of grass at tupping time.  So if you change your tup fairly regularly you might put a couple of particularly good lambing years down to the tup when in fact it's due to the unpredictability of farming conditions.