Texel Scrapie and Micropthalmia Information

[easyram1]

I am a non active member of the Texel Sheep Society. Can someone who is an active member please explain the rationale behind the following email I have received from the Society. 'The restrictions on the registrations of males that carry the Scrapie VRQ allele or are Micropthalmia Carriers( C/G genotype) have been removed: meaning that all birth notified males are eligible for registration'. With lots of commercial sheep farmers keeping Texel x or Texel x Tex x or even Texel x Texel x Texel x ewes surely this is a totally irresponsible decision that ignores the mayhem that may be caused long term in the national ewe flock.?

 

[gatepost]

Couldn't really work that one out myself, our ewes and stock rams new and old are/were all resistant, but I can only assume some bloodlines are not totally and the respective owners maybe want to keep the line and have the opportunity to ,breed problems out? I thought only resistant rams were going to be eligible for registration from next year.

 

[Ysgythan]

Yes. DEFRA have brought in new interpretations of animal welfare regulations which mean you can’t refuse to register animals based on the tests, but you should publish the test results so that buyers can ensure animal welfare.

We’ve had to DNA test rams being registered for years. Now it seems the Society have been testing for micropthalmia. We asked for our results to be made public on iTexel when we found out they could do this.

This year the Society suggested vendors test rams for sale in advance of the sales as progeny of carriers would be ineligible for registration from next year. However it took 6-8 weeks as the samples had to go to NZ for processing. We only did a handful of pedigree potential lambs as a result as unsurprisingly there’s a cost.

Then DEFRA stepped in and said you can’t refuse registration. They said something similar to the Shorthorns, which resulted in their “U” class animals.

So yesterday, rather than it being up to the breeder or owner, the micropthalmia results were all made public on iTexel.

It’s now clear what bloodlines are problematic. There are some interesting findings. I’ll not go further on a public forum, if you’re interested enough and have a computer and an enquiring mind you’ll work it out.

Apparently the reason there’s a test in NZ is that’s it’s quite a problem there. From what I’ve seen it’s very limited in UK Texel lines. The rams forward at the Builth NSA will either be tested, or will have three to four generations of parentage tested.

I understand your concern on cross breeding, especially with NZ Texel lines, but source G/G resistant tups and the lambs will be fine even if the dams are carriers.

 

[easyram1]

Yes. DEFRA have brought in new interpretations of animal welfare regulations which mean you can’t refuse to register animals based on the tests, but you should publish the test results so that buyers can ensure animal welfare.

We’ve had to DNA test rams being registered for years. Now it seems the Society have been testing for micropthalmia. We asked for our results to be made public on iTexel when we found out they could do this.

This year the Society suggested vendors test rams for sale in advance of the sales as progeny of carriers would be ineligible for registration from next year. However it took 6-8 weeks as the samples had to go to NZ for processing. We only did a handful of pedigree potential lambs as a result as unsurprisingly there’s a cost.

Then DEFRA stepped in and said you can’t refuse registration. They said something similar to the Shorthorns, which resulted in their “U” class animals.

So yesterday, rather than it being up to the breeder or owner, the micropthalmia results were all made public on iTexel.

It’s now clear what bloodlines are problematic. There are some interesting findings. I’ll not go further on a public forum, if you’re interested enough and have a computer and an enquiring mind you’ll work it out.

Apparently the reason there’s a test in NZ is that’s it’s quite a problem there. From what I’ve seen it’s very limited in UK Texel lines. The rams forward at the Builth NSA will either be tested, or will have three to four generations of parentage tested.

I understand your concern on cross breeding, especially with NZ Texel lines, but source G/G resistant tups and the lambs will be fine even if the dams are carriers.

Thanks for your full explanation. As I said yesterday I cannot imagine anyone happy to use any ram in any breed that carries a V for Scrapie and the the micropthalmia issue sounds a bit scary particularly if one is 'inbreeding' or 'Line breeding' as master breeders in my previous life used to do! The DNA test for micropthalmia is one of the very many tests all our imported NZ Texels are subjected to whilst in quarantine pre export to the UK. No carriers are allowed and all rams have to be ARR/ARR

 

[Ysgythan]

Thanks for your full explanation. As I said yesterday I cannot imagine anyone happy to use any ram in any breed that carries a V for Scrapie and the the micropthalmia issue sounds a bit scary particularly if one is 'inbreeding' or 'Line breeding' as master breeders in my previous life used to do! The DNA test for micropthalmia is one of the very many tests all our imported NZ Texels are subjected to whilst in quarantine pre export to the UK. No carriers are allowed and all rams have to be ARR/ARR

I hope everybody involved is as straight as you in that case. I’m still struggling with DEFRA’s logic here. Test everything and cull any carriers. Even the basic maths, let alone animal welfare says that must be the way, doesn’t it?

 

[neilo]

Thanks for your full explanation. As I said yesterday I cannot imagine anyone happy to use any ram in any breed that carries a V for Scrapie and the the micropthalmia issue sounds a bit scary particularly if one is 'inbreeding' or 'Line breeding' as master breeders in my previous life used to do! The DNA test for micropthalmia is one of the very many tests all our imported NZ Texels are subjected to whilst in quarantine pre export to the UK. No carriers are allowed and all rams have to be ARR/ARR

What is microphthalmia and what does it do?

As for the Scrapie Genotype, everything here has been ARR/ARR for many years, but I don't publicise it, nor do I recall a single commercial ram purchaser ever asking about Scrapie genotype.

 

[Ysgythan]

What is microphthalmia and what does it do?

As for the Scrapie Genotype, everything here has been ARR/ARR for many years, but I don't publicise it, nor do I recall a single commercial ram purchaser ever asking about Scrapie genotype.

it’s only relevant to export really, which since Brexit and now Blue Tongue is buggered anyway.

 

[easyram1]

What is microphthalmia and what does it do?

As for the Scrapie Genotype, everything here has been ARR/ARR for many years, but I don't publicise it, nor do I recall a single commercial ram purchaser ever asking about Scrapie genotype.

I do not know precisely what happens when a carrier is mated to a carrier but some resulting lambs are born without eyes so really no one would want to be owning or selling carriers.

 

[Global ovine]

What is microphthalmia and what does it do?

Causes blindness by affecting the optic nerve and all the structures in the eyeball. Usually seen as very small eyes or virtually no eyes at all.

The single recessive gene was imported into NZ in the Texel consignments that came from Europe in the late 1900s. It was not noticed when these consignments were still in quarantine, but emerged at extremely low incidence when progeny where being bred on commercial farms. This may have been a result of large scale multiplication and mixing of imported blood lines that its very low incidence was noticed, as by then thousands of Texels were being born.
The Gene Testing Lab at Lincoln Uni soon made a test available after researching the cause of this rare problem introduced into the NZ national flock.
The NZ Texel breed Soc. to their credit pounced onto eradication of this disease. This has made it now a non event in commercial buyers minds nowadays, as stud breeders test their sires.

Fortunately the move to incorporate Texel genetics into the more recent Maternal Composites has been achieved with the guidance of having the Micropthalmia test available.

One could consider this disease introduction to NZ as "the one that nearly got away".