I am a longtime horse breeder, and that is what I write about here on Substack.
I am interested in general things like calculating coefficients of inbreeding, to simplify things for my readers. I would do it by Wright's formula, but I am finding it difficult to explain. Any thoughts? Have you already done an article on this?
What coefficients are realistic for poultry breeders to use as their "limit?"
Hi, Jeanette - Thanks for commenting. I want to write something much longer to explain how I work, but in short, I don't really use inbreeding coefficient calculations. I find they are too abstract, not rooted enough in reality. I have never used any of the mathematical formulae too much, as I find them all very static and theoretical, not always really reflective of the reality no the ground, though certainly, most o the researchers I have worked with did use various mathematical approaches. My approach is to evaluate each individual situation, observing its particular reality and go from there. I am not concerned with inbreeding, unless there are observable deleterious genes or obvious inbreeding depression. When there is no issue visible, I inbreed, always carefully observing for any problems that may arise and then figure out what to do, what reasonable or best new direction to take or outcross to use, once the problems start to arise.
In other words, every mating I do is a test mating, and I rely on test mating results to make all determinations for that particular line or mating. When there are few or no deleterious recessives in a line, and the line can produce exceptional individuals for all the intangible traits I am paying attention to, with no or only slight obvious problems, I prefer inbreeding to strengthen those good traits. In other instances, if I am working with a line deriving from recent outcrossing, I am also not too concerned with inbreeding, and again, treat every mating as a test mating and then make evaluations based upon the actual results, the facts on the ground. Once I am well into a line and have a good understanding of its positive and negative traits, I may then apply some of the mathematical formulae, but I don't rely on them, as they are two dimensional, in my opinion, as what looks right on paper may not prove out in reality. Just my take, and I certainly don't think it is wrong to use the maths, but I trust my observations of the actual results of test matings over formulae.
I haven't written any articles on this, but it is something I will be tackling in a future video. Thanks again for your comment! I hope this gives something helpful, but if not, let me know if you have any other questions, as perhaps I can fine tune what I am trying to convey.
Hello Brian
Thank you for your articles.
I am a longtime horse breeder, and that is what I write about here on Substack.
I am interested in general things like calculating coefficients of inbreeding, to simplify things for my readers. I would do it by Wright's formula, but I am finding it difficult to explain. Any thoughts? Have you already done an article on this?
What coefficients are realistic for poultry breeders to use as their "limit?"
Hi, Jeanette - Thanks for commenting. I want to write something much longer to explain how I work, but in short, I don't really use inbreeding coefficient calculations. I find they are too abstract, not rooted enough in reality. I have never used any of the mathematical formulae too much, as I find them all very static and theoretical, not always really reflective of the reality no the ground, though certainly, most o the researchers I have worked with did use various mathematical approaches. My approach is to evaluate each individual situation, observing its particular reality and go from there. I am not concerned with inbreeding, unless there are observable deleterious genes or obvious inbreeding depression. When there is no issue visible, I inbreed, always carefully observing for any problems that may arise and then figure out what to do, what reasonable or best new direction to take or outcross to use, once the problems start to arise.
In other words, every mating I do is a test mating, and I rely on test mating results to make all determinations for that particular line or mating. When there are few or no deleterious recessives in a line, and the line can produce exceptional individuals for all the intangible traits I am paying attention to, with no or only slight obvious problems, I prefer inbreeding to strengthen those good traits. In other instances, if I am working with a line deriving from recent outcrossing, I am also not too concerned with inbreeding, and again, treat every mating as a test mating and then make evaluations based upon the actual results, the facts on the ground. Once I am well into a line and have a good understanding of its positive and negative traits, I may then apply some of the mathematical formulae, but I don't rely on them, as they are two dimensional, in my opinion, as what looks right on paper may not prove out in reality. Just my take, and I certainly don't think it is wrong to use the maths, but I trust my observations of the actual results of test matings over formulae.
I haven't written any articles on this, but it is something I will be tackling in a future video. Thanks again for your comment! I hope this gives something helpful, but if not, let me know if you have any other questions, as perhaps I can fine tune what I am trying to convey.