Moving Forward- Breeding for Resistance to Marek's Disease

[Nambroth]

We can still use either MDV1 or GHV2, or even just use "Marek's Disease" for the disease itself. Though to confuse it even more- an article or two uses GaHV2!

If the pathologist though was going to name a specific gallid herpesvirus, they should have known it was serotype 2 for Marek's Disease. Similar to a Ford salesman talking about "that Chevy over there, the blue Fusion". It would be OK for me to mix brand and models up- but a salesman that sells that model car?

Gotcha-- thanks for the information. It always seemed odd to me that they would abbreviate HVT the way they did, but Mareks was MDV? I of course do not know naming conventions, but still it helps to call it gallid herpesvirus now, when we are looking at it in depth, because it's important to remember it is indeed a species of herpes, and acts as such.

I'm sorry, I'm just rambling now!

 

[chooks4life]

To avoid cross-posting, I think you guys may want to check out this link and some info I found. I selected what seemed to be the most pertinent bits on that thread.
Quote:
Or, you could just skip straight to the source of that info: http://www.ncbi.nlm.nih.gov/books/NBK92750/

But it's a bit of a lengthy read.

Best wishes.

 

[seminolewind]

I understand wanting to breed for resistance. I do see that there's some who have. What has me

is the chickens that are resistant or don't get the tumors, but carry Marek's. And in carrying Marek's, can cause immunosupression. And then you get opportunistic illnesses. Which cause a chicken to waste. So how do we breed for resistance in a chicken to not carry Marek's, get immunosupressed , or give the virus to others?

 

[chooks4life]

I understand wanting to breed for resistance. I do see that there's some who have. What has me

is the chickens that are resistant or don't get the tumors, but carry Marek's. And in carrying Marek's, can cause immunosupression. And then you get opportunistic illnesses. Which cause a chicken to waste. So how do we breed for resistance in a chicken to not carry Marek's, get immunosupressed , or give the virus to others?

As far as I can see it, there's not really any way to be 100% sure without clinical testing, which is still beyond most of our reaches, as far as being able to affordably implement it regularly goes.

If you know for sure you have Marek's in your flock and you maintain infected birds for generations, and after sufficient decades they still show no obvious immunosuppression despite being exposed, you could reasonably state that your birds are not suffering that effect of it, to the best of your knowledge anyway. Whatever that's worth. I've seen no immunosuppression in mine, I wonder what causes it; possibly a different strain?

We still don't know what the average survivor presents as, because the focus is more on cull/vaccinate/replace, not preserve/perpetuate resistant stock/lines. What permanent or long term physiological changes do they exhibit?

I think it's probable that there are non-symptomatic survivors as well as ones that are mildly or severely symptomatic of something to do with the disease or the damage it causes, so possibly in breeding for resistance we should have a much more long-term view, i.e. an individual is only truly considered resistant if it goes on to die of old age and nothing else, barring perhaps an accident.

As for non-shedders, that to me sounds like something that would be quite hard to test for within the usual hobbyist's means, but, not impossible. To be sure, a lab must needs be involved though.

Best wishes.

 

[seminolewind]

I am very interested in breeding for resistance . But not just covering tumor growth. My interest is more along the lines of those Marek's exposed birds who appear to waste away at some point in their adult life and whether it's Marek's immunosuppression leading to opportunistic bacterial growth, or whether theses exposed birds' wasting is treatable.

From what I've experienced and results of 3 necropsies, they were older unvaccinated birds. The last one who was wasting and lethargic I immediately put on sulfadimethoxine (for over growth of cocci), wormed a 2nd time before that, and Tylan to treat for subclinical Clostridium ( also chronic low level effects.) In 5 days she became an eataholic and put on weight , and now clucks for treats.

I'll have to work on this more in the future.

 

[Northie]

[quote namecouldbolewind" url="/t/894589/moving-forward-breeding-for-resistance-to-mareks-disease/630#post_14340024"]I am very interested in breeding for resistance .  But not just covering tumor growth.  My interest is more along the lines of those Marek's exposed birds who appear to waste away at some point in their adult life and whether it's Marek's immunosuppression leading to opportunistic bacterial growth, or whether theses exposed birds' wasting is treatable.

From what I've experienced and results of 3 necropsies, they were older unvaccinated birds.  The last one who was wasting and lethargic I immediately put on sulfadimethoxine (for over growth of cocci), wormed a 2nd time before that, and Tylan to treat for subclinical Clostridium ( also chronic low level effects.)  In 5 days she became an eataholic and put on weight , and now clucks for treats. 

I'll have to work on this more in the future.
[/quote]

I think you could be caught on the idea that all birds with Marek's disease either grow tumors and die or are weakened and die from something else. It could just be something else alone. Not saying that it isn't exactly what you think you're seeing, but there's always the third option of death due to _____________, unrelated to Marek's.
I ment that to be read in a friendly tone.

 

[Michael Apple]

I think you could be caught on the idea that all birds with Marek's disease either grow tumors and die or are weakened and die from something else. It could just be something else alone. Not saying that it isn't exactly what you think you're seeing, but there's always the third option of death due to _____________, unrelated to Marek's.
I ment that to be read in a friendly tone.

That's a very good point. How many posts in the Emergencies section of the forum pertaining to leg paralysis could be due to a riboflavin deficiency in the diet, and not the common assumption of Marek's? How many nerve problems are due to calcium deficiency/absorption and not Marek's?

 

[speckledhen]

That's a very good point. How many posts in the Emergencies section of the forum pertaining to leg paralysis could be due to a riboflavin deficiency in the diet, and not the common assumption of Marek's? How many nerve problems are due to calcium deficiency/absorption and not Marek's?

YES, absolutely. I see much conclusion-jumping in Emergencies, especially with Marek's. Simple injuries, tendon damage, etc, are tossed into the Marek's pile. Even in birds with Marek's, there can certainly be things that happen to them entirely unrelated to the disease.

 

[chooks4life]

YES, absolutely. I see much conclusion-jumping in Emergencies, especially with Marek's. Simple injuries, tendon damage, etc, are tossed into the Marek's pile. Even in birds with Marek's, there can certainly be things that happen to them entirely unrelated to the disease.

All true. But when there's a common and very serious cause of certain leg problems, it makes sense to mention it just in case.

Lately some few people have been going around posting threads linking to or describing as many different causes of the same symptom as possible. It's great, I wish we had more threads like that, preferably stickied ones.

 

[speckledhen]

All true. But when there's a common and very serious cause of certain leg problems, it makes sense to mention it just in case.

Lately some few people have been going around posting threads linking to or describing as many different causes of the same symptom as possible. It's great, I wish we had more threads like that, preferably stickied ones.

Agreed.