Breeding for disease resistance

[Poultry Friend]

I am wanting to do this with my birds, but I am not sure the best way to do it. From what I can figure, this is what I should do. Am I right?

Option 1

1. Any bird that gets sick at all gets instantly culled.

Problems with this option

If there is a disease like mareks that is highly fatal, no birds may survive.

Option 2

1. Keep sick birds to see who survives. Breed these birds in hopes that they pass on this resistance.

Problems with this option

I might not have many birds for long.


I think long term this will pay off. I plan on raising heritage birds and these birds were bred to be mainly ignored and would survive with little intervention. I feel if I breed these birds to need tons of help to live (special diet, incubation, drugs, ect) that I am not really preserving the breed.

Could someone who has done this give me some pointers?

 

[Kevin565]

I have very little insight but IMO option 2 would be a big mistake. Breeding those birds wouldn't allow for disease resistance. The birds still got sick. They were just strong enough to survive. Meaning your breeding the strongest weaklings.

 

[Poultry Friend]

Well, my thoughts on that is based on human immune response. Once you 'survive' an infection, you have resistance. For some diseases that have a very high mortality, I would assume that by keeping the birds that can survive and get better, you would be keeping the genetics with the best immune response.

In the short run, it would be pretty horrid, but after 4 of 5 generations, I would *hope* the birds would have pretty rocking immune systems.

If I kill all the birds that get sick I am not guaranteed that the birds that did not get sick are immune. They might just have avoided getting sick. (so they would be lucky)

By keeping the birds that got sick and recovered, I would hope that those birds would have a stronger immune system and that they could genetically pass that on. By repeating this with their chicks, I would refine the pool more. I would expect that any birds that got sick would recover even quicker. Eventually, I would want any bird exposed to a disease to show no symptoms at all.

Again, this is based on mammalian genetics, so it could be flawed.

 

[Poultry Friend]

Found this: http://www.bifconference.com/bif2006/pdfs/Snowder.pdf

Looks like there are a few issues with doing this:

1. Breeding a highly effective immune system can result in an overactive immune system that attacks healthy cells.

2. Breeding a bird that is highly immune to one disease may make the bird very susceptible to another disease.

I still want to do this, but it looks like it will be much harder then I thought it would be.

 

[Poultry Friend]

"Immune responsiveness, challenging an
animal with an antigen or vaccine and
measuring antibody response or production, has
been useful in poultry (Lamont et al., 2003)"

Not sure I would be able to measure antibody response, but AP microbiology was my favorite class, so I might look into how it could be done. Crossing my fingers it can be done with some tools I can buy online and a microscope! LOL

 

[Poultry Friend]

Found more articles.

http://ec.europa.eu/research/infocentre/export/success/article_693_en.html

http://www.crcnetbase.com/doi/abs/10.1201/NOE0824706326.ch10

http://www-naweb.iaea.org/nafa/aph/stories/2010-chicken-breeds.html

This one is really good! http://www.biomedcentral.com/1471-2164/10/20/

Turns out having a chicken with blood type B15/B15 (homozyous for B15) gives it greater resistance for Mareks, at least when it is also combined with some natural resistance already.

 

[Poultry Friend]

Now this is interesting!
http://www.ncbi.nlm.nih.gov/pubmed/6306630

This abstract shows that B15/B15 is also highly susceptible to Mareks, which leads me to believe that there could be a variation between the MHC (Major Histocompatibility Complex) within this type that would allow for some birds (the ones that are from lines that show some resistance to Mareks) and are homozygous and birds that show no resistance and are homozygous to show such differing mortality rates.

While searching out B15 type would be desirable, it would only be so if you can also find the other genes which would impart some resistance to begin with, otherwise those same birds would seem to be more prone to die from the disease!

 

[Poultry Friend]

http://journals.tubitak.gov.tr/veterinary/issues/vet-00-24-5/vet-24-5-2-9901-7.pdf
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[Poultry Friend]

Sorry for posting so much, but I figure that if I am interested in this, someone else might be too at some point, and as I find this info, I want to share it!

http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=41901



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So this might be what is happening with the homozygous B15 birds. They are more prone to mortality with Mareks, but with some antibody response, they are better protected.

Now I just have to figure out how to blood test my birds! LOL

 

[Poultry Friend]

http://birdflubook.com/a.php?id=72



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I guess if I want nice disease resistant birds I also need to make sure I don't breed with too much emphases on super high egg production or meat. I have dual purpose birds and I need to keep them like that if I want healthy birds.



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Wow! This really changes how I will cull chicks! I might decide not to cull the lower weights and instead let them mature and see which is the healthiest birds. I might be killing the ones with the strongest immune systems!