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Hilly



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PostSubject: Re: Inbred selection   Fri Feb 11, 2011 11:08 am

Mean Spirit wrote:
I wonder how you'd know when a strain is regressed to its base core?

I'd guess that mating two different highly inbred strains having the same phenotypes in some traits of interest would probably result in a uniform group of calves. The parents would be themselves very likely quite homozygous if they were both (1) inbred by pedigree and (2) significantly phenotypically depressed. And you might assume that the two strains are pretty alike genotypically if the same phenotype is a good proxy for genotype. So the progeny would be pretty homozygous too, and would breed like that-- predictable.

But--
(1) If the two strains are alike genotypically, why would you do the cross? There shouldn't be any hybrid vigor, and there wouldn't be any complementary traits if the cattle are alike. If your goal was to just change the names in a pedigree, it'd work, but I don't think that'd be your goal.

(2) If the two strains are not alike genotypically, why would you do the cross? You might be making a new breed, or something like a new breed, but I'm not sure why you'd go to the trouble. Will the new "breed" be any better at anything than the parent strains?


Good points, I have ask the same questions many times scratch .

I dislike the terms regression and depression as they seem misused I prefer to think of the average of the center of the following chart as a more true expression of the population in visual production values.
Production values would be depressed or regressed left of center,on average, there will be exceptions or outliers here as well I would think. But how many of us have closed the herd and bred cattle long enough to even find out what our average True value looks like...




With the mainstream seed stock breeding practices we have became accustom to closer to 75% heterozygosity a area of the chart that should be reserved for commercial beef production of seedless fruit as the underlying genetic chaos at this level of production is unsustainable without the more stable parts on the opposite end of the spectrum being used as seed stock.
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MKeeney
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PostSubject: Re: Inbred selection   Fri Feb 11, 2011 1:14 pm

Mean Spirit wrote:
I wonder how you'd know when a strain is regressed to its base core?

I'd guess that mating two different highly inbred strains having the same phenotypes in some traits of interest would probably result in a uniform group of calves. The parents would be themselves very likely quite homozygous if they were both (1) inbred by pedigree and (2) significantly phenotypically depressed. And you might assume that the two strains are pretty alike genotypically if the same phenotype is a good proxy for genotype. So the progeny would be pretty homozygous too, and would breed like that-- predictable.

But--
(1) If the two strains are alike genotypically, why would you do the cross? There shouldn't be any hybrid vigor, and there wouldn't be any complementary traits if the cattle are alike. If your goal was to just change the names in a pedigree, it'd work, but I don't think that'd be your goal.

(2) If the two strains are not alike genotypically, why would you do the cross? You might be making a new breed, or something like a new breed, but I'm not sure why you'd go to the trouble. Will the new "breed" be any better at anything than the parent strains?

what if udder`s were a strength of one strain, feet a weakness... and feet were the strength of the other strain; udders a weakness?
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Mean Spirit



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PostSubject: Re: Inbred selection   Fri Feb 11, 2011 1:28 pm

That would be a reason to do the cross. But you wouldn't be increasing the homozygosity in the traits that fixed udders and feet, would you? And if you weren't fixing those traits, wouldn't that likely limit how much "good" the bull buyer gets re: the unfixed traits?

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pitchfork

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PostSubject: Re: Inbred selection   Fri Feb 11, 2011 10:25 pm

Mean Spirit said "That would be a reason to do the cross. But you wouldn't be increasing the homozygosity in the traits that fixed udders and feet, would you? And if you weren't fixing those traits, wouldn't that likely limit how much "good" the bull buyer gets re: the unfixed traits? "


It seems to me that that cross could be done and of course would likely be more heterozygous for both desirable udder and feet structure, thus limiting it's initial usefulness a a prepotent line for those traits. However with careful selection and fixing of traits with inbreeding/linebreeding the desirable traits could be eventually be concentrated.

Ken Nimrick
Western Illinois
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MKeeney
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PostSubject: Re: Inbred selection   Sat Feb 12, 2011 12:45 am

I guess what `i`m fishing for here is best exemplified by the two sheets of paper with holes in them, each representing a strain...put the two together and they cover{complement} each other`s holes...can the strains combined, then cover more holes in the next cross, than if we used only one of the single strains?
I`m wanting the answer to be yes...but the only thing I have right now is an IMHO Smile Smile Smile


Last edited by MKeeney on Sat Feb 12, 2011 6:33 am; edited 1 time in total
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Kent Powell



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PostSubject: Re: Inbred selection   Sat Feb 12, 2011 2:53 am

I would guess that is where the pre-testing of the combining ability of the lines would be necessary.


There is a little breed based heterozygosity article in the new ACJ.

http://chicattle.org/
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Kent Powell



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PostSubject: Re: Inbred selection   Sat Feb 12, 2011 3:54 am

http://books.google.com/books?id=noYZAQAAIAAJ&dq=galloway kyloe cross&pg=PA197#v=onepage&q=galloway%20kyloe%20cross&f=false

Pages 197 and 215




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MKeeney
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PostSubject: Re: Inbred selection   Sat Feb 12, 2011 7:43 am

Keystone wrote:
http://books.google.com/books?id=noYZAQAAIAAJ&dq=galloway kyloe cross&pg=PA197#v=onepage&q=galloway%20kyloe%20cross&f=false

Pages 197 and 215




good stuff Kent... I gotta feed and come back to reading the argument tonight...yelp, there`s nothing new under the SUN Smile
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Mean Spirit



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PostSubject: Re: Inbred selection   Sat Feb 12, 2011 9:21 am

Keystone wrote:
I would guess that is where the pre-testing of the combining ability of the lines would be necessary.


There is a little breed based heterozygosity article in the new ACJ.

http://chicattle.org/

That's kinda interesting Kent. But I'm a little doubtful of the timeliness of the underlying data (it says 2001). I wonder if the data on the black continentals is based on older (and less Angus-y) animals? I think it would be pretty surprising if the black continentals of 2011 aren't much more closely related to Angus cattle than more traditional continentals ( such as white Charolais or Red Maines or Yellow Simmentals).

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Mean Spirit



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PostSubject: Re: Inbred selection   Sat Feb 12, 2011 9:23 am

MKeeney wrote:
Keystone wrote:
http://books.google.com/books?id=noYZAQAAIAAJ&dq=galloway kyloe cross&pg=PA197#v=onepage&q=galloway%20kyloe%20cross&f=false

Pages 197 and 215




good stuff Kent... I gotta feed and come back to reading the argument tonight...yelp, there`s nothing new under the SUN Smile

That guy doesn't care too much for that Bates character and his minions. But he makes some pretty good points.
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Grassfarmer



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PostSubject: Re: Inbred selection   Sat Feb 12, 2011 9:59 am

Keystone wrote:
http://books.google.com/books?id=noYZAQAAIAAJ&dq=galloway kyloe cross&pg=PA197#v=onepage&q=galloway%20kyloe%20cross&f=false

Pages 197 and 215


Interesting read Keystone. One thing that surprised me a bit was the mention of Red Galloways. I'll be honest, apart from the North American ones I don't think any such cattle exist. I grew up in the heart of Galloway country, with Galloway cattle and went to school with kids whose ancestors registered Galloways in the first herdbook of the breed in Scotland. Not once did I ever see, read about, or hear even circumstantial evidence of the existence of Red Galloways. I know it's said here that "they are just like the black Angus with the red recessive gene" I simply don't know if that's true or an invention to cover up the creation of a pseudo breed by some other breeding means (crossing with something red). Anyone know any more about the subject?
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Tom D
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PostSubject: Re: Inbred selection   Sat Feb 12, 2011 8:44 pm

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Grassfarmer



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PostSubject: Re: Inbred selection   Sat Feb 12, 2011 10:44 pm

Tom D wrote:
http://books.google.com/books?id=EAoCAAAAYAAJ&lpg=PA437&ots=Bg38at1ppl&dq=celtic%20cattle%20history&pg=PA435#v=onepage&q=celtic%20cattle%20history&f=false

Iain, check pages 439 and 440.

Which book are these the pages of? the one it links to doesn't have a preview.
TIA
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Tom D
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PostSubject: Re: Inbred selection   Sun Feb 13, 2011 1:11 pm

It appears to be from a research paper on "The Inheritance of Coat Color in Shorthorns" published in a turn of the century scientific journal "Biometrika". The paper begins on page 427 of the journal. Amazing what you can find on the world wide net with the old google machine. Things sure get muddy fast when you start researching the history of all these "pure" breeds. Iain, how would you explain the family tree of british breeds?
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Grassfarmer



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PostSubject: Re: Inbred selection   Sun Feb 13, 2011 3:10 pm

I'm maybe stupid but how do you get to read the pages you quote? scratch
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MKeeney
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PostSubject: Re: Inbred selection   Sun Feb 13, 2011 8:40 pm

Hilly wrote:
Mean Spirit wrote:
I wonder how you'd know when a strain is regressed to its base core?

I'd guess that mating two different highly inbred strains having the same phenotypes in some traits of interest would probably result in a uniform group of calves. The parents would be themselves very likely quite homozygous if they were both (1) inbred by pedigree and (2) significantly phenotypically depressed. And you might assume that the two strains are pretty alike genotypically if the same phenotype is a good proxy for genotype. So the progeny would be pretty homozygous too, and would breed like that-- predictable.

But--
(1) If the two strains are alike genotypically, why would you do the cross? There shouldn't be any hybrid vigor, and there wouldn't be any complementary traits if the cattle are alike. If your goal was to just change the names in a pedigree, it'd work, but I don't think that'd be your goal.

(2) If the two strains are not alike genotypically, why would you do the cross? You might be making a new breed, or something like a new breed, but I'm not sure why you'd go to the trouble. Will the new "breed" be any better at anything than the parent strains?


Good points, I have ask the same questions many times scratch .

I dislike the terms regression and depression as they seem misused I prefer to think of the average of the center of the following chart as a more true expression of the population in visual production values.
Production values would be depressed or regressed left of center,on average, there will be exceptions or outliers here as well I would think. But how many of us have closed the herd and bred cattle long enough to even find out what our average True value looks like...




With the mainstream seed stock breeding practices we have became accustom to closer to 75% heterozygosity a area of the chart that should be reserved for commercial beef production of seedless fruit as the underlying genetic chaos at this level of production is unsustainable without the more stable parts on the opposite end of the spectrum being used as seed stock.

Craig, just an excellent post of thoughts here...the graph really pretty much explains what will happen at whatever level we proceed...
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Hilly



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PostSubject: Re: Inbred selection   Sun Feb 13, 2011 10:52 pm

MKeeney wrote:
I guess what `i`m fishing for here is best exemplified by the two sheets of paper with holes in them, each representing a strain...put the two together and they cover{complement} each other`s holes...can the strains combined, then cover more holes in the next cross, than if we used only one of the single strains?
I`m wanting the answer to be yes...but the only thing I have right now is an IMHO Smile Smile Smile

That is an interesting question Mike... I would think using the sheet theory you would cover more holes moving forward with the cross. But I would think that it would be undeniable that the distributions would increase as well and crossing of the sheets can only happen if they exist.

I believe that it is still be better than current mainstream seed stock as I can put it into some context with my own personal experience. As I have related in the past I am relatively new to the beef industry and in my search for a smaller sort on my replacements I toured a number of herds, a trend that I began to see was the crossing of two closed herds produces very useful cows. I proceeded to use bulls from such crosses and reduced my on farm sort from the days of using bulls from long term breeders with open herds.

I am convinced if more breeders simply closed down a portion of their herds and bred their own cattle, eventually exposing the True production value of the herd as well at the same time, beginning to tame the deviation.... even if they stayed away from the regression of tighter bred cattle it would be a big step forward. They could still run the majority of the herd on the right side of the chart and I would think preferably out crossed with another breeder’s complementary closed strain as opposed to the random bull lottery... IMBlueSkyO Smile
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EddieM



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PostSubject: Re: Inbred selection   Mon Feb 14, 2011 9:55 am

Quote :
Can similar in type and purpose, but non-related, inbred strains regressed beyond phenotypic acceptance, be crossed and the single cross product be a parent stock improvement in consistency and predictability to the industry over what currently exists?

I'm slow, but what's new? Would the black baldies of the 60's be anything like this as an example? Prior to a lot of AI, more of herd breeding, a push had been made to make them beltbuckle sized, so it was about as close as the industry came to two sheets and random holes as far as I know. I'm still trying to figure if I want to be humble about this or not. I'll get back on that after I see what kind of answers I get!! pale
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