The Accidental Smallholder Forum
Livestock => Sheep => Topic started by: waterbuffalofarmer on September 05, 2016, 04:33:43 pm
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I know a few of you have said that you wouldn't buy them because they produce too many lambs, etc, etc. I discovered something today, which i should have seen last year. It was in the Lleyn society catalogue/book 2015, it talks about genotypeing sheep, if thats how its spelt ;D They talk about 2 types of Lleyn, which are within the Lleyn breed, The normal Lleyn and the gwynnedd Lleyn. It says here that the normal Lleyn ewes have a lambing percentage of 160-170% whereas the mature gwynedd ewes will lamb at 250%. They also say that if you want to breed for these qualities then you will have to have a flock of 75% normal ewes and 25% gwynedd ewes, the rams from these flocks will have a 200% prolificacy, you then must not put high prolificacy rams on high prolificacy ewes, as there is a big chance that the ewe lambs born out of them will be barren. Instead they say put high prolificacy rams on normal ewes to acheive a higher lambing %. Hope this makes sense, I am sure there is a lot more to it..... Anything anyone would like to add? Apparently they used a similar method, by also testing pedigrees for this type of fecX gene, to eliminate scrapie. :) The gene is most commonly found in older ewes which have had triplets
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You can genotype for any known marker gene for which there is a reliable test
The National Scrapie Scheme was a great example and managed to dramatically reduce the incidence of scrapie within the national flock
There are various fecundity genes which we know about including the Fec x , Inverdale & GDF9 genes
They are used to increase fecundity in low output/hill breeds but you have to bear in mind that lambs born does not equal lambs reared ;)
Also regularly ''genotyped'' are Myomax, Cold tolerance, footrot tolerance etc
We have recently identified an allele identified with worm resistance but there is plenty of work to be done before it has any chance of being validated
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That's very interesting, wbf, thanks for posting that
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You can genotype for any known marker gene for which there is a reliable test
The National Scrapie Scheme was a great example and managed to dramatically reduce the incidence of scrapie within the national flock
There are various fecundity genes which we know about including the Fec x , Inverdale & GDF9 genes
They are used to increase fecundity in low output/hill breeds but you have to bear in mind that lambs born does not equal lambs reared ;)
Also regularly ''genotyped'' are Myomax, Cold tolerance, footrot tolerance etc
We have recently identified an allele identified with worm resistance but there is plenty of work to be done before it has any chance of being validated
Is it true that a lot of the flocks in scotland/ireland have been bred for worm resistance? I was in contact with a Lleyn breeder who bought in a ram because they are breeding for worm resistance, the people he bought from. What methods would be used for doing that, I assume the similar method which they use for the myomax gene? How long would it take for those genes to be isolated and for the flock to become fairly worm resistant? Would it also depend on regions too?
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There is some work on worm resistance being done in the lleyn breed---those doing it are part of the lleyn performance recording group
We do it in the Exlana group too and have been collecting data for the last 8 years (I have been doing this for much longer but on a smaller scale and its scale that counts in statistics)
We take individual FEC when the lambs are between 6 and 9 month old and put this data into a BLUP analgise to get a FEC EBV which we use to make breeding decisions
Last year we did some trials to see how far we had got with this----the ewes in the top 25% for resistance were only excreting 50% of the eggs that those in the bottom 25% were
So it works and we are seeing very measurable results
There are other tests for worms including a saliva test that the Lleyn guys have been trialling with Glasgow Uni. ---they should have better validation at the end of this year
We have also looked at markers for worm resistance with Roslin Institute (6 year project), the report is due to be published very soon but the basic end message is that there are alleles we have identified with worm resistance but much more work needs to be done to see if they offer a worthwhile method of selecting for worm resistance
At the moment the best method seems to be by doing plenty of FEC and breeding accordingly----FEC has a good heritability --about the same as growth rate so is easy to select for
But it isn't an overnight fix, you have to incorporate it as a long term goal in a breeding program----I think it would be reasonable to get a flock with the potential to reduce egg output by 50% within 4 generations
The other problem is that in general farmers don't care about breeding for worm resistance---they have an easily accessible drug and will keep using it until they have no other choice
This is why I am in favour of some kind of restrictions on the availability of anthelmintics----prescription only? Not sure but we need to do something before it is too late
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I ink this was on country file 2 weeks ago
Maybe catch up on the iplayer