Strategies for Breeding with limited Gene Pool

Discussion in 'Exhibition, Genetics, & Breeding to the SOP' started by HeritageHenNut, Nov 11, 2016.

  1. HeritageHenNut

    HeritageHenNut Chillin' With My Peeps

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    I recently came into possession of a quad of Crevecoeurs, and in Canada...the gene pool is particularly shallow. I would love to dedicate my time to helping this breed recover & breed towards its traditional purpose as a table bird. Looking for any suggestions.
     
  2. Wappoke

    Wappoke Chillin' With My Peeps

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    With only 4 birds to breed, (as you said) you have a limited gene pool to work with. What characteristics are not found in the birds that you want to improve?

    If I was in your shoes, I would do some crossing between the birds and see if I could improve a characteristic. When you do your crosses, you will have to produce a bunch of chicks (100) at once or a bunch over time. Keep accurate records of which chicks came from which parent.

    For example, if you cross the male bird ( I am assuming you have only one male) with hen A and you produced 100 chicks. From this 100, you have two females that are larger than the parent hen and one male larger than the parent male- you know which hen carried the autosomal or sex-linked gene(s) that when paired with the parent male produced a larger bird.

    The next step to do a cross between the larger male offspring and his two sisters. Produce a bunch of birds and analyze the results. Determine if size has improved or not.

    If the first cross only produces female offspring that are larger, you know that a sex chromosome carried by the male may be responsible for the larger size and some locus on the chromosome may be responsible for the larger size. (this would be true for subsequent crosses also)

    If the first cross only produces larger males, then the female carried a sex chromosome that when combined with one or both of the male sex chromosomes carried the growth factor locus. (this would be true for subsequent crosses also)

    If size is a problem, you have to remember- size usually takes a large number of crosses to obtain a goal. Size like dwarfism is usually associated with a single locus and that can be sex-linked or autosomal. In either case, the dwarfism is pleiotropic ( effects a number of characteristics and systems) and is due to reduced amounts of a growth factor or reduced number of receptors for the growth factor.

    You will want to go in the opposite direction. You will want to increase the things that cause the bird to grow faster and larger, This could be something like the bird is hungry most of the time and eats more food or the bird has a thinner lining on the intestine that will allow for the blood stream to absorb more nutrients. It could be that the bird inherits a locus that increases the amount of growth factor produced by a gland or the brain.

    Today's table birds grow fast and can obtain large sizes in a very short time. This is accomplished through quantitative loci. In other words, a number of different genes and parts of the DNA in a bird are all working together to produce the rapid and large growth.

    Many people think only genes control characteristics but there are also parts of DNA that control the expression of a gene. So when breeding, it may not be a gene at all that is causing an outcome but a part of DNA that is controlling the gene expression (larger size). Sometimes it is a gene regulator that is needed to increase growth and not a gene.

    If you want to out cross, that is a possibility if your birds do not have the genetic makeup to grow larger.

    If you outcross to a different breed, there are a number of different ways to accomplish the goal.You just have to get started and go from there. I would be glad to work with you on your project. You can PM me and I will give you my email address. I have worked with broiler crosses in the past and have read up and studied the subject.
     
    Last edited: Nov 12, 2016
  3. 3riverschick

    3riverschick Poultry Lit Chaser

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    My Coop
    Laws governing the breeding of standard fowls; a book covering outbreeding [!] inbreeding and line breeding of all recognized breeds of domestic fowls, with chart, 1912
    by Card, Wetherell Henry,
    https://archive.org/details/cu31924003158312
    Here, read this book, it will tell you how to breed the four and start a family of birds. Judge Card was a renowned poultry man. He created the White Laced Red Cornish breed. Judge Card had an exceptional gift for making complicated topics simple. Could often be found at poultry shows with a circle of listeners as he expounded and made simple various breeding topics. Note these in the book are Laws. Not opinions or theories. if you do this, then that will happen. I love this little book and go back to it often.
    Best,
    Karen
     
    1 person likes this.
  4. HeritageHenNut

    HeritageHenNut Chillin' With My Peeps

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    Thank you! I've been searching high and low for breeders up here but so far just a few people that used to have them :-( I'll definitely follow the book and maybe get these guys on track up here.
     
  5. ejcrist

    ejcrist Chillin' With My Peeps

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    I was looking at that book and have a question for the chart on page 15. In the second block (middle) it says on top of the chart, "Cockerel from 1914 mating of 1911 dam to 1917 pullet from 1911 sire". Is that second part of the sentence, "...1917 pullet to 1911 sire" supposed to be, "1914 pullet to 1911 sire?" I think it is because the 1917 offspring hasn't been born yet. I'm thinking it being an old re-print maybe the resolution is bad, or I'm just not understanding it correctly.

    I'm reading as much a I can about breeding because I'm trying to design my first breeding programs for next spring, and I have a trio and a quad of two breeds and a single pair of another (Buff Orpington's) so line breeding is of particular interest in the case of the BO's since I only have the one pair. I guess though it's applicable to all my cases because it might make better sense to line breed the females of the trio and quad for at least three years before deciding if I should cross the other lines. I just don't know at this point - I'm a bit overwhelmed.
     
  6. ejcrist

    ejcrist Chillin' With My Peeps

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    Sorry - I meant to direct this question to 3riverschick.
     
  7. ejcrist

    ejcrist Chillin' With My Peeps

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    I went back and reviewed a book I had read earlier called The Mating and Breeding of Poultry, and in one of the beginning chapters it explains line breeding much better so that I can understand it. Maybe it's just me but the chart didn't seem to match up with the linebreeding example given in "Laws Governing the Breeding of Standard Fowls." I also have the short book put out by the Livestock Conservancy but it's mainly an overview without specific examples. I wish there was a more recent book on poultry breeding strategies and when each one makes sense but I've never found anything like that. The older books are good but I'm sure there's probably been some developments since they were written.

    Did everyone here make a detailed plan when they first got involved with breeding to the SOP? If so, did you start with good stock and went with line breeding by default or did you choose some other method? I was reading about clan breeding a little while ago where you toe punch all the offspring from a given mother and then avoid breeding two birds with the same toe punch going forward. I believe that was a good method if you have mediocre stock to start with and you're not trying to fix a line until you you develop birds with the best traits first. If anyone has any comments on this method as well I'd be glad to hear.
     
    Last edited: Nov 22, 2016
  8. miss heny

    miss heny Genetic Expert in learning Premium Member

    I myself was given that book and I suspect that even within the concept of line breeding people have different "views". Myself I would probably attempt to either meld the methods or use one that looks the most appealing to me.
     
  9. ejcrist

    ejcrist Chillin' With My Peeps

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    Thanks for the input miss henny. I'm with you on that. Since I have excellent birds to start with I'm going to line breed each pair separately, and then if I end up with offspring out of that mating that when put together could produce an even better result I'll mate them. So I guess I'll be doing line breeding and spiral breeding when it's beneficial. I see what you mean about melding methods.
     
  10. miss heny

    miss heny Genetic Expert in learning Premium Member

    :thumbsup I am going to be breeding offically Swart Honas, using three out of the four birds I own so I plan on using line breeding to develop my strain until I aquire a good quality rooster to sire a secondary line.
     

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