When does it become inbreeding?

Discussion in 'Sheep' started by ONThorsegirl, Oct 17, 2005.

  1. ONThorsegirl

    ONThorsegirl Fergusons Family Farm

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    I have a question about pedigrees. I was wondering about the whole inbreeding situation.

    on the papers when they have the same names on the paper in what spot on the papers do you concider to close together.
    This might sound confusin but here it goes. If grandfather (father of both sire and dam) is the same for the sire and dam is that too close together?

    How about the Great Grandfather? If there is the same Grandfather on both sides (Sire and Dam)

    Melissa
    Sorry if I confused to many of you's!!
     
  2. minnikin1

    minnikin1 Shepherd

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    My opinion is admittedly cynical but:

    All these are conditions are considered "inbreeding" UNLESS

    a self appointed "expert" first blesses them with the "okie dokie".

    Mind you, 99.9 percent of okie dokies result in profits for the "expert".

    This is not knowledge I have gleaned solely from observing breeders of sheep, but rather, from breeders of whatever. The trend holds true from species to species.
    I consider myself an expert on this phenomenon, BTW.
     

  3. ONThorsegirl

    ONThorsegirl Fergusons Family Farm

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    Ok So I understand that this inbreeding, butto what extent is it just way to close for the lines to cross. I kind of understand what you are say except for that, What do you think? It shoudln't be done? or is it alright? Sorry I just couldn't completely understand.

    Melissa
     
  4. kesoaps

    kesoaps Well-Known Member

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    Do you mean the sire and dam are half brother/sister? Then yes, I'd say that this would be too close, at least for my comfort zone. Some people will purposely breed this close if they know their genetic line well enough, and they're willing to take the gamble. Others would wait a couple more generations.

    Here's the thing with sheep or cattle...if it doesn't work you just eat them. That doesn't exactly happen with horses or dogs (well...not usually.) So if you give it a shot, and it doesn't work, you just don't do it anymore.

    More often than not you get dwarf/stunted offspring before you end up with severe birth defects. If you were to continually cross like this, you'd progress beyond small deviations towards the larger, easier to spot troubles often associated with line/inbreeding. So even if you get a good cross the first time, you're going to want to outcross those offsrping. HTH
     
  5. eieiomom

    eieiomom Well-Known Member

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    From what I have been told by sheep professionals (University "professionals"), and what has been written up in magazine articles such as in "The Shepherd", it is safe to breed back (line breed), if the bloodlines are at least two generations away, also better on just one side -not both.
    I also have been told that smaller size would be the main characteristic that would show up if breeding was too close.
     
  6. Celtic Herritag

    Celtic Herritag Celtic Heritage Farms

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    I do believe that line breeding refers to one generation, father to daughter, son to dam, any further besides that and it is considered inbreeding. Not all inbreeding is bad though they do it to resurect (sp?) many old dying breeds or outcross for undesireable qualities. This is done very scientificaly though with both "partners" undergoing gene mapping to determine what the cross will get.

    Your problem seems like you got half siblings that were bred together. So you have a lamb that has 50% concentrated blood. In linebreeding you have 75% concentrated blood. Since they were half siblings and not exact siblings I'd say that your sheep would be an okay producer, but breed it with entierly different lines.
     
  7. ONThorsegirl

    ONThorsegirl Fergusons Family Farm

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    Ok I will make something up and then put it on here so you can all see and tell me what you think.

    Melissa
     
  8. Ross

    Ross Moderator Staff Member Supporter

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    Line breeding is a controlled form of inbreeding using inbreeding co-efficients calculated from a multi-generational pedigree. A father daughter breeding would be inbreeding plain and simple. An Aunt/Nephew could be an acceptable line breeding, it kind of depends on just how related beyond that they are! Wright's co-efficient of inbreeding is the old school method, there's a better one now and I'm sorry to say I'm just too tired to think straight and remember details tonight. I'll try to post more tomorrow
     
  9. ONThorsegirl

    ONThorsegirl Fergusons Family Farm

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    Dam
    Krammer - Cherway Lionel 12E​
    - Effie 73E​

    Lane Luba - KWASI​
    - Effie 73E​

    Sire
    Lucky - Cherway Lionel 12E​
    - Century Lane Joanne​


    So what do you think of this out come if it were to happen? To close are should it be fine? I don't have sire information for the Sire. All of the names mentioned are realy names.

    Melissa Sory I had no Lines to show you exactly where the names go but I hope you have the idea.
     
  10. OregonGuys

    OregonGuys Well-Known Member

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    Inbreeding/linebreeding, along with selection and heaving culling, is a powerful tool used to create excellent family lines within breeds of animals. Inbreeding increases the odds that any existing good genes will pair up and express themselves. However, it also increases the odds that any existing bad genes will pair up. Since most bad genes are recessive, they only exhibit themselves when there are two copies. Inbreeding does NOT create problems. Inbreeding forces hidden recessive bad genes to the surface where they can be culled. Outbreeding / outcrossing simply hides the bad genes and passes them on to the next generation.

    A novice breeder, especially those without a good eye for selection and those unwilling to cull heavily, should stay away from inbreeding themselves, BUT should be happy to acquire excellent animals from an expert’s inbreeding/linebreeding program.

    Animals from a well-managed inbreeding/linebreeding program are likely to be homozygous for excellent traits and likely have had most negative traits culled out. These inbred/linebred animals are considered prepotent. Because they have two copies of good genes, they will definitely pass those good genes to their offspring.

    So in answer to the original question, if you are considering breeding two related animals, consider these questions: Are those two animals top quality to begin with? Does the common relative have some outstanding characteristics and few flaws? Do you have an eye for excellence? Can you spot flaws? Are you willing to ruthlessly (and humanely) cull the rejects? If you answer yes to these questions, then you should not be afraid of inbreeding. If you answer no to any of them, then you should stay away from inbreeding/linebreeding (especially if you are unwilling to heavily cull).

    Hope this helps...
     
  11. ONThorsegirl

    ONThorsegirl Fergusons Family Farm

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    Ok Thanks, That helps and I think it will be fine as anything that doesn't turn out with the results will be used for meat so I think we will be fine.

    Thanks, Melissa