Moving Forward- Breeding for Resistance to Marek's Disease

[speckledhen]

Quote: I relate. I hate to think I would have to go back to hatchery stock just to get the "good" MD vaccine, not after years of letting them all leave one by one and trying to get better stock and breeding from them. Mine may be pets, but I want well-bred pets, ones that look like the breed they are supposed to be. I want layers, yes, but I like having something a little better than "just" layers. Even good quality heritage old-line stock lays eggs. Call me selfish but I want both.

 

[tridentk9]

Any change in a bird's routine could be considered stress, but it is unlikely to have an impact. Sustained stress like drastic changes in the weather, being transported, and being relocated etc. is real stress.

Good management means a lot. Healthy and happy birds are generally problem free. If breeding, being especially mindful of health and vigor means a lot. That comes first.

Yes. And it is what they consider stress. A different food, someone in their spot, a moved lawnmower. OMG- a hat! Stranger Danger! LOL- try raising African Greys, they're notorious for stressing about change. Level of reaction to stress is individual.

Happy things are stressing too. Little bits of stress spaced out so A- the cortisol levels, etc go back to baseline and B- the individual learns how to deal with (or live through) stress are good though. Ups and downs. Not too far up and time between to relax and think.

 

[gjensen]

Apparently inhaling the MDV is worse than the injections typically used in lab testing. The full article is free. http://www.tandfonline.com/doi/abs/10.1080/03079450601156075#/doi/full/10.1080/03079450601156075
L6 is the resistant line, L7 is the susceptible line. These birds were pathogen free, had never been in contact with nor vaccinated against MDV. Most of the L6 birds infected by intra-abdominal injection were still alive when the study ended 70 days post infection. Some interesting results with dosage of infection.

Chicks get their maternal antibodies mostly from yolk and some from albumin that is eaten at hatch. It was explained by one of the contributors to Avian Immunology by Schat, et al http://www.sciencedirect.com/science/book/9780123969651 I'll have to look for the write-ups on maternal antibodies.


Quote:

I agree that it "shouldn't" happen, but it does. That is part of the reason I said that it is not that simple, and used this as an example. The inheritance of disease resistance is not as cut and dry as color genetics. I found a few examples skimming through poultry genetics books that are meant for the commercial industry. Both modern and outdated. If it was that simple, the commercial poultry industry would have their problems solved. There is plenty of economic incentive to do so. They also have the money and scale to do it. It isn't as if they have not done any work on it.
I am no expert on this subject and will not pretend to be. It is an interesting topic.

This *might* be true of other viruses such as Marek's. The part about inactivation by the host's innate response can be true of MDV. And .... that leads to the question below.

Does anyone know if there is a commercially available titer test for Marek's? It would certainly help with some of the questions of exposure and resistance. IDDEXX doesn't list one. http://edis.ifas.ufl.edu/vm102

 

[Nambroth]

I do not know what everyone does or does not. I know what you are saying though.

I am not going to look away concerning type and color. I do believe that health and vigor comes first. It has to. Everything else is for naught otherwise. Not to mention that a vigorous flock has a way about them that makes that much more enjoyable.
My birds are not "pets", but I enjoy them as if they were.

I would say that if you found a breeder of a breed that has been successful over a long period of time, you would do well. That level of commitment by someone usually means a sincere breed enthusiast that wants to do well by the breed. Well bred birds tend to have good long term health.
I can think of a few good ones off the top of my head. The catch is what you mentioned. You may have to vaccinate the young birds yourself. That is if you want them vaccinated, or need them vaccinated.

Sorry if my post was confusing. I just meant that a good strong, healthy bird is more valuable to me, personally, than one that is perfect to its breed. I am confident there are breeders out there that meet both expectations!

 

[gjensen]

Sorry if my post was confusing. I just meant that a good strong, healthy bird is more valuable to me, personally, than one that is perfect to its breed. I am confident there are breeders out there that meet both expectations!

I did not take it as a negative. People are people and we tend to drift to one extreme to another. That is as true for people keeping and breeding poultry as anything else.

And there are excellent breeders out there. I stressed long term breeders, because it takes time to swallow it all. It takes time to learn what the breed is. There are a lot of particulars to learn with poultry. Then trial an error, backtracking from mistakes etc. Getting it in our heads, and putting into practice is another matter all together. I am trying to learn breeding the color buff, and though it is a single color, it is a challenging color. It is a color that no one will ever quit learning. And that is the color alone.
I admire the achievements that some have made and sustained over a period of time. Particularly, if the birds are healthy and productive. There is not a lot of them around. Many of us ride the shirt tails of what others have achieved.

Anyways. I do not want to interrupt this thread. I will leave it alone. I commented because I think the topic is an interesting topic.

 

[seminolewind]

Quote:

I relate. I hate to think I would have to go back to hatchery stock just to get the "good" MD vaccine, not after years of letting them all leave one by one and trying to get better stock and breeding from them. Mine may be pets, but I want well-bred pets, ones that look like the breed they are supposed to be. I want layers, yes, but I like having something a little better than "just" layers. Even good quality heritage old-line stock lays eggs. Call me selfish but I want both.

Don't be too worried about hatchery stock. I think we need to pick our hatcheries. I believe Meyer (?) is the one who sells their juvies vaccinated with everything-which is pretty good and thoughtful. Seems that my hatchery birds live the longest. I've only had one EYP that I know of, and probably because most of my chickens are not known to be egg machines.

I lost a rooster yesterday-just flipped over and died.

I lost a Polish last night, possibly to coccidiosis or enteritis. She was the 3rd of 3 that were from resistant parents. I think that Marek's exposed birds seem prone to other common ailments that most birds build a resistance to. I am moving the other 4 out of that pen and letting it rest for now.

Fern is weak and has trouble standing. I will be sending her for a necropsy. I think I'm using the necropsies now to try to figure out what I'm not doing right.,

Does anyone feel that rotating pens would help in some way? Or make things worse?

 

[chooks4life]

Don't be too worried about hatchery stock. I think we need to pick our hatcheries. I believe Meyer (?) is the one who sells their juvies vaccinated with everything-which is pretty good and thoughtful. Seems that my hatchery birds live the longest. I've only had one EYP that I know of, and probably because most of my chickens are not known to be egg machines.

I lost a rooster yesterday-just flipped over and died.

I lost a Polish last night, possibly to coccidiosis or enteritis. She was the 3rd of 3 that were from resistant parents. I think that Marek's exposed birds seem prone to other common ailments that most birds build a resistance to. I am moving the other 4 out of that pen and letting it rest for now.

Sorry for your losses. Polish in particular do seem to be on average very susceptible birds.

Fern is weak and has trouble standing. I will be sending her for a necropsy. I think I'm using the necropsies now to try to figure out what I'm not doing right.,

Does anyone feel that rotating pens would help in some way? Or make things worse?

Are you treating the soil with anything? Controlling pathogen overload is more likely to help you than rotating pens in my opinion... But, of course, treatment using natural means may take some time depending on what you use, and you could lose more birds in the meanwhile, so moving them may be right for you.

All my birds were always kept on the same ground year after year, in a completely mixed flock, and that ground was only treated with lime, not the caustic sorts either. Well, that and the deep litter composting method, which controls a lot of problems all on its own. I always kept infected birds among the flock, even when there were chicks around, and never had any issues due to that.

Just lost a few very susceptible individuals to Marek's over the years, one here, one there, never an outbreak or anything like that, never any 'inbetween' cases which showed symptoms but recovered; all I ever saw were occasional severely susceptible ones which died, but looking back, they were birds with a few problems, not just one; once I weeded out the family lines responsible for leukosis I stopped having Marek's deaths (I know, they can look similar) which seemed to only happen to random descendants of those family lines; in particular a cross between two unrelated lines produced those birds despite both parent lines appearing robust and resistant, and all their other offspring with other lines being healthy... Always good to keep records, so many things make sense only in retrospect!

Anyways. I do not want to interrupt this thread. I will leave it alone. I commented because I think the topic is an interesting topic.

If you have thoughts or information to offer, then it's not interrupting. We're all working towards a common goal here, even though we're approaching it from different angles and perspectives.

On one of your earlier posts, you mentioned breeding for resistance being a long term project and of variable ratios of success etc; I thought I'd just point out that this has already happened with mongrels and is still happening, so those comments about breeding for resistance you made apply more to purebreds. I agree, it's not an easy job for such breeders especially.

One of the benefits of mongrels is that they've been traveled all over, just about nobody practices biosecurity or prophylaxis with them, and they've been exposed to multiple strains of everything, then mixed, and remixed, and plenty of them have also been left neglected to try to survive without additional feeding or care, so only the fittest survived to breed.

Best wishes.

 

[seminolewind]

Thanks, Chooks. I moved them all to a different coop with a wire floor and nice pen. I saturated everything with Virkon and scrubbed everything. I have them on sulfadimethoxine just in case. The pen in question will be empty for a while. Maybe caustic lime would be good in there. It's a closed pen.

With my BR, Fern, I think her illness is a chronic one, not acute. She's been lethargic on and off for a year, but always had an appetite.

My gf said to me "You have 32 chickens? You mean you'll be going thru this 32 more times???" (mourning)
Is that the truth!

 

[speckledhen]

Don't be too worried about hatchery stock. I think we need to pick our hatcheries. I believe Meyer (?) is the one who sells their juvies vaccinated with everything-which is pretty good and thoughtful. Seems that my hatchery birds live the longest. I've only had one EYP that I know of, and probably because most of my chickens are not known to be egg machines.

I lost a rooster yesterday-just flipped over and died.

I lost a Polish last night, possibly to coccidiosis or enteritis. She was the 3rd of 3 that were from resistant parents. I think that Marek's exposed birds seem prone to other common ailments that most birds build a resistance to. I am moving the other 4 out of that pen and letting it rest for now.

Fern is weak and has trouble standing. I will be sending her for a necropsy. I think I'm using the necropsies now to try to figure out what I'm not doing right.,

Does anyone feel that rotating pens would help in some way? Or make things worse?

It's not that I'm worried about hatchery stock as far as vaccinations. I don't want hatchery stock because most of them, the Barred Plymouth Rock comes to my mind first and the Delaware second, do not look like what the breed should look like. They are below par in what they ought to be, even aside for all the disease factors. It was all my hens from Ideal who had EYP/salpingitis/internal laying. The breeder stock fared much, much better. Even the daughters of hatchery stock did somewhat better than their mothers did. Hatchery Barred Rocks, Wyandottes, Rhode Island Reds and Buff Orp all died with the same couple of things. The best luck I've had with hatchery stock is my Buff Brahma. Before that, only one hatchery hen died of what I feel was just old age, one of the Buff Orpingtons at 6 1/2 years old, the last original.

I want to open up every one from now on and at least look at the livers, but DH balks at that. He is softer hearted than I am on that count. He doesn't want his last memory of a hen he loved to be splayed out on the table that way. I understand, but if I have any question, she's being opened up by either me or the lab.

 

[gjensen]

If you have thoughts or information to offer, then it's not interrupting. We're all working towards a common goal here, even though we're approaching it from different angles and perspectives.

On one of your earlier posts, you mentioned breeding for resistance being a long term project and of variable ratios of success etc; I thought I'd just point out that this has already happened with mongrels and is still happening, so those comments about breeding for resistance you made apply more to purebreds. I agree, it's not an easy job for such breeders especially.

One of the benefits of mongrels is that they've been traveled all over, just about nobody practices biosecurity or prophylaxis with them, and they've been exposed to multiple strains of everything, then mixed, and remixed, and plenty of them have also been left neglected to try to survive without additional feeding or care, so only the fittest survived to breed.

Best wishes.

I think there is some validity in what you are saying, but many points you raised (I can speak for myself) happens within a breeder's flock. What "nature" does for a land race "breed", I do for my flock. Instead of nature being the pressure, I am. If I apply pressure to a point where I only retain the fittest examples, then over time I have a flock more tolerant of my environment. But in addition to health and vigor, I have the opportunity to select good typed animals that are productive.

Another point that I would add is that just because a flock of "wild mongrels" are surviving, does not make them necessarily more resistant. I am going to use the Key West chickens as an example. Obviously they are surviving. They have adapted and are continuing to adapt to their environment. They also are not withstanding heavy exposure. They are being exposed, but the level of that exposure is relevant. Those same bird's offspring in close confinement would likely be just as susceptible as a "pure breed" that has been carefully selected on the same Island.
In my area wild Turkeys are a good example. Obviously they are very rugged, and able to thrive within their environment. They begin to have problems when they are kept within close proximity of each other. Feeding or baiting Turkeys is illegal here. A good reason not to do it is that it makes them more susceptible to disease and parasites. It is not that there is a change in their tolerance. There is a change in their level of exposure.
Management is important.

Concerning the trade of mongrels. Is there a trade in mongrels? What I have seen is mixed breeds being traded within a given area where the pressures are more or less uniform. I am not aware of mongrels being shared cross country, and if they are, it is a recent occurrence. I am not certain what you mean by all over.There is haphazard trading of birds in my area. Usually it is hatchery stock, and sometimes they are mixed hatchery stock. They are not anymore resistant to disease (as a whole) than any other. The owners usually have more problems with disease, but the problem is usually rooted in the management of these birds.

I think your point is valid when you compare extremes. The land raced breeds of tropical Africa are better suited for their environment, than mine would be. Mine are originally from Peru by the way. Still if those land raced birds, if bred to fix type and color, would be no more or less resistant because they were. They would only become more or less resistant if the breeder used birds that were susceptible or more resilient. They are only removed from the gene pool if they die. If they succumb and recover they breed, and if they are resistant they breed. A breeder has the opportunity to remove a susceptible bird from the gene pool. A breeder has the opportunity to make faster progress on this one point because he/she has control over specifics.
The points you used with asserting that mongrel flocks would be more resistant could be used for pure breeds to. Some yes and some no. Many do not treat, trade their birds across country, and expose them too many birds at the shows etc. Some of course, do treat their birds and coddle them along. The variation is in the variety of breeders, as much as there is variation within breeds and strains.

There are some breeds and strains that are notorious for being highly susceptible to some pathogens. Then there are some that have a reputation for being especially tough. Most would fall in between. I would not disagree that some flocks of mongrels would be more resilient than the average bird. I also do not believe a bird is necessarily more resilient just because it is a "pure breed", or a mixed breed either.

A good thing about chickens is that they are tough and adaptable. They would not be around the globe if they were not. Properly managed they generally do pretty good. I have not had a sick bird in 6-7 years.

I never intended to say that we could not or should not breed for resistance. I prefer to call it breeding for health and vigor because I want to be realistic with my expectations. I would manage a flock of mixed breeds or a flock of pure bred birds the same. My expectations would be the same.
I am for or against neither. I have a grading project, and a "modified" grading project on my yard. I am no purist. At the same time, I realize that if I let a flock of mixed breeds breed haphazardly on my yard, they would quickly become very inbred.