PW, I think I have already mentioned this to you, not sheep but goats, a doe had a single kid in January and twins (small) 17 days later. I suspect one ovary fertilised and the other on the next cycle. I wonder how many similar things we have all missed when lambing in the field or on the hill with bigger numbers.
Thanks for sharing these fascinating reports, guys! No doubt, as old mcdonald says, many things like this go unreported.
It’s not too difficult to envisage species with bicornuate uteri i.e. 2 fairly self-contained “limbs” to the uterus, like sheep and goats, to empty each horn separately some hours, or even a day apart.
When the distance apart is the length of an oestrous cycle, it is techically known as Superfetation [http://en.wikipedia.org/wiki/Superfetation] and very rare in farm animals.
When I was working as a vet in Yorkshire, a pig farmer showed me a sow that had given birth to a single piglet, then exactly 3 weeks later gave birth to several more – all healthy. Superfetation is very hard to explain in a sow, where a fall in ovary progesterone plays a key role in farrowing and the same hormone is essential to the maintainance of pregnancy.
farmerbill, Stay sceptical. You will be conned far less often than those who believe more. At the same time, I know what happened in my case this year. When I kept a lot of sheep I relied on numbered ear tags for posititve ID. I still do even with my handful of goats although I know most of them due to different colourations. The goats seem to know their own breeding well enough. We have to house them at night because of packs of stray dogs. After putting them in tonight I went back to find them all lying in their family groups, the majority have kidded and it is quite fascinating to see a couple of generations lying side by side with their new lambs, and in one case tonight 3 generations with the youngest adult still in-kid.
Granddads aunt swore she had a ewe lamb a single then 3 weeks later lamb another live single………way before my life started so I can’t vouch for it, but I never thought she made things up.
The oddest thing I ever saw with stock was when I had sheep. I had a Suffolk ewe lamb a dinky live lamb, and then a crescent shaped “thing” with a hoof on each end(just one digit, not an entire hoof) totally enclosed in lamb skin. I took the thing to the vet, he had a name for it, 20 years after the fact I cannot remember it. The other lamb lived about a month, never thrived and finally died. The ewe never lambed again.