[DartmoorLiz]

Hi , 
I'm a bit of a newbie (except for some posts on Devon hedges a while ago) and I love this forum which seems full of kindred spirits  .  My question is does any one know if or how a ram influences his wives to produce twins  ? 
I only ask because we've got about 20 scottish black face ewes and 15 lleyns and I put them all to a lleyn ram this year.  After scanning we had more than usual twins among the black faces and my friend who sold me the lleyn ewes said that was because of the influence of the ram.  I just don't understand how the ram can persuade the ewe to ovulate 2 eggs    and I was hoping someone here might know.
Thanks
Liz

[Big Light]

Genetic selection may be made for breeding stock that are more prolific but in the end its the ewe that produces the eggs and natures general rule is to release more eggs when times are good as there is a greater chance of animal survival. So if the females fit and are well ( but not over) fed ( can be from grass) at the correct time of the year then there is a better chance of more lambs than if the sheep are malnourished. Would be interested if any one can tell me otherwise i.e they smell the ram through the fence etc

[Rosemary]

My understanding is that prolificacy comes from the ewe - ie the ability to release multiple eggs, implant multiple embryos and sustain multiple pregnancies. So in any year, not influenced by the ram.

But using a tup that is a  twin / triplet, and retaining his daughters that are twins / triplets is selection for prolificacy.

The increased prolificacy in the Blackies will be down to better grazing and forage - on the hill, a healthy single is the aim due to the harsh conditions but twins from Blackies on lowground isn't unusual.
 

[Marches Farmer]

I think twinning has low heritability but I guess there's also a possibility of low fertility in the ram having some effect.

[SallyintNorth]

My understanding is the tup passes on the genetics for multiple births to his daughters (and presumeably for passing the same on to his sons) but that in a given tupping any genetic effects are all on the ewes' side.

Many nutritional and seasonal effects also come into play, affecting both ewes and tup.  For maximum lambing percentage, both parents should be in good (not fat) condition and on a rising plane of nutrition going into tupping.  Note also that the subsequent treatment of the ewes can influence implantation.

However, one could imagine that a tup with highly active sperm might manage more multiple fertilisations / implantations than one with less of a less active sperm? 

What causes an egg to split for indentical twins, I don't know.

Jaykay might know more when she checks in.

[DartmoorLiz]

Thanks for your replies so far .  I had not thought of multipul births being a case of implantation and supporting twins as well as 2 fertile eggs.  And the thought that active sperm find more eggs is intriguing (like my spelling, sorry).  I have been told that identical twins (ie one fertilised egg splitting into 2 babies) is down to chance in humans and not heritable so I suppose that's the same for sheep.
 
Please keep your replies coming, I can't get enough sheepy stuff.

[VSS]

using a tup that is a  twin / triplet, and retaining his daughters that are twins / triplets is selection for prolificacy.

Exactly.

Using a ram that is one of twins or more will have no effect on the number of lambs conceived in the first generation BUT his daughters will generally be more likely to have multiple births.

Increasing prolificacy in this way is a slow process. If you want to improve more quickly, keep female lambs that themselves are one of twins - that way you might get some improvement in two years rather than four. If you doo both, you should get a significant increase in litter size.

Beware though that you don't go too far - no one want too many sets of triplets as then there are not enough teats to go round!

[Big Light]

The perverse thing is that the best looking tups are singles !

[SallyintNorth]

We prefer singles and find it hard to buy tups that aren't twins or even triplets

We actively don't flush, keeping the ewes on hard ground before and during tupping and not giving them minerals until after tupping.  In our system, ewes rearing one lamb well with little help works as well or better than ewes rearing twins, needing more input and the lambs usually being much later away, meaning more costs and usually lower prices for them.  If it's a good year for grass we may buy in some store lambs to eat the grass and make a little money after Christmas - but in a bad year we aren't overstocked.

[Marches Farmer]

Yes, it's one of the attractions of sheep farming - there's no one right answer and you can make up your own flock plan to suit your land, climate, schedule and needs.  The saying round here is "Better a good single than poor doubles".

[VSS]

I don't disagree with you Marches - it all depends on what your land will hold. On reasonable land I would say that the ideal scenario is to have every ewe rearing twins, but if your ground is harder then that could be too many sets of twins. This year our ewes scanned at nearly 170%  - very high for welsh mountains, and rather more than I would like.

Sally re not flushing - I know where you are coming from and in some ways to not actively flush would reduce our twin numbers, but on the other hand, havin a very tight compact lambing period is very important to us, especially as we have to have ewes lambing during the set period of our lambing course. We just wouldn't get the same tight lambing of we didn't flush, so I guess we have to put up with the extra twins.

As you say, no right or wrong answers when it comes to flock management- horses for courses is what it is all about.

[SteveHants]

We prefer singles and find it hard to buy tups that aren't twins or even triplets

We actively don't flush, keeping the ewes on hard ground before and during tupping and not giving them minerals until after tupping.  In our system, ewes rearing one lamb well with little help works as well or better than ewes rearing twins, needing more input and the lambs usually being much later away, meaning more costs and usually lower prices for them.  If it's a good year for grass we may buy in some store lambs to eat the grass and make a little money after Christmas - but in a bad year we aren't overstocked.

And on the other side of the coin - I like my ewes to be able to rear triplets and select for those that can. I expect to get them away off grass by the end of the year. This is the south of England though on chalk downland mostly. I would be slightly worried if I had a lot of trips though, the singles go first, then twins, leaving the last of the autumn flush of grass for the trips. Some trips will inevetably go as stores because I have not perfected it yet.


Having said that, because of the nature of my grazing, it is impossible to flush (unless I used energy buckets or something, but I'm too tight fisted for that) ewes. Most of my ewes have Lleyn in them somewhere (aside from the pure Wilts Horns)....

[Marches Farmer]

With the unusual weather we've had over the past two years I'd feel rather cautious about putting ewes on poor ground with a view to flushing them pre-tupping.  Just been through my lot and normally it's a battle to keep condition off the Southdowns but not with the poor quality of grass over the last year or so.  Several single-bearers have had to go in with the twinners for feeding - usually it's the other way around.

[SallyintNorth]

Yes, this time around, 'not flushing' has included feeding concentrate from the start of tupping right through, whereas normally we wouldn't cake until after Christmas.  We do have a higher proportion of twins this time than usual, though, so we obviously erred on the side of generous.  But the ewes are mostly in good shape, so we're pleased we fed as we did.

[SteveHants]

Equally - I have no way of separating ewes with multiples etc. They just have to do on what they have. Works okay so far....