Which Ewes to Cull

[mezz]

We need to understand what goes on to get triplets to select for or against this occurrence.
Between 20 and 30% of ewes that scan twins shed 3 eggs. There is a genetic effect transferred from the sire that influences embryo survival that ranges from 67 -98% embryonic survival. Most ewes that scan triplets do not repeat triplets every pregnancy. To select against triplets is possible, but rams must also be retained for use out of that flock, or selection is only applied to the female side of that gene pool. However it takes a shepherd's lifetime to reduce tripleting incidence by 10%, economically just peanuts compared to selecting for many other more important traits such as Survival, Growth and Disease resistance.

Selecting for triplets is possible, but once flock scanning exceeds 210% the incidence of quads starts to rise and over 30% of triplets started as 4 eggs shed. This rise and replacement of ewes of lower order litter size reflect that of the incidence of triplets that rises quickly above a scanning of 165%. Having a high genetic ability to be prolific is advantageous as the ideal lambing % can be controlled by managing ewe live weight, or more specifically BCS. Far more achievable than culling.

The greater the proportion of larger litter size the greater the incidence of birthing problems. High litter size is more common in older ewes which compounds survival problems.

Hi Global Ovine, Are these percentages roughly the same for singles and twins as for twins and triplets? Thank you.

 

[Global ovine]

Hi Global Ovine, Are these percentages roughly the same for singles and twins as for twins and triplets? Thank you.

Proportionally similar, ie about 10 - 12% embryonic loss of twinning potential ending up as singles.

 

[Farmer_Joe]

Funny i get a group of the same ewes (not every one literally prob 30%) having triplets year on year, after scanning and batching i often recognise them from the year before.

 

[serf]

Does this work with goats?

No , you just end up with a pile of dead goats else !

 

[unlacedgecko]

Had one a week or two ago. Escaped by herself through a weak spot ìn fence. I fixed and put her back in. Next day she was out again and brought another two with her. Sporting a nice pretty red tag now for a bus pass later in the season.

Why wait till the end of the season? Ewes and lambs are a strong trade!

 

[Estate fencing.]

Why wait till the end of the season? Ewes and lambs are a strong trade!

I just had 2 welsh ewes and 4 lambs grazing the side of the road. There now locked in the shed and will go to market tomorrow, I don’t want them to teach the other 60 ewes and lambs how to run at 3 strand electric.

 

[DairyGrazing]

Friends father runs a 2 notch in ear system. No notches replacement ewe 1 notch terminal sire 2 notches cull

Notches for foot rot, lambing problems etc.

 

[Woolless]

Friends father runs a 2 notch in ear system. No notches replacement ewe 1 notch terminal sire 2 notches cull

Notches for foot rot, lambing problems etc.

Nice and simple

 

[unlacedgecko]

Friends father runs a 2 notch in ear system. No notches replacement ewe 1 notch terminal sire 2 notches cull

Notches for foot rot, lambing problems etc.

I do similar. Although this current high price means everything with 1 notch has gone! Last 39 being picked up tomorrow.

 

[Green farmer]

Why wait till the end of the season? Ewes and lambs are a strong trade!

Wouldnt like to offload anything that wasnt 100% to another farmer. I'll leave till end of season and straight to factory along with her lamb.

 

[TGM]

what about breeding and culling according to performance? with sheep now tagged with EID, the process of linking lambs to mothers at birth is not difficult on a good quality tag reader. weigh the lambs at 3 months old and judge according to the total 90 day production of lamb for each sheep. average over a number of years and you're breeding from the best most milky ewes. If you want a better picture judge also according to 56 day weight of the lambs, and if you want to go a bit further, weigh your ewes close to tupping and add in percentage efficiency in the mix where a 75 kg ewe producing 75 lamb at 90 days is 100% efficient and a 100 kg ewe producing 65 kg lamb at 90 days is 65% efficient. Pool that all together and your breeding selection of female lamb replacements from the best sheep is easy. throw in a final selection to only keep lambs from the rams which gave the best 90 day weights from his offspring t get the ram genetics for fast growth coming through and you're well on track to success. The question was which to cull - so the answer is the opposite of which to breed from - the ones with worst 90 day lamb weights, worst efficiencies, worst average lambs per lamb crop averaged over a few years etc. There's not a lot to this, it's a simple process - a half hour job at selection time for culling or breeding if you use decent software that does it all for you. - the biggest challenge is tagging the lambs at birth and linking to their mothers. If that fails, the performance recording process falls over. So you have to persuade the shepherds at a lambing time that this is something they must do. Again there's not a lot to it. Less than 1 minute to record a birth record on a good reader - ewe tag, lamb tags, sex of lambs, breed, weight of lambs, easy/ difficult birth etc.