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 Direct vs maternal calving ease

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df



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 10:25 am

Bootheel wrote:
df wrote:
Bootheel wrote:
df wrote:
Calving ease. Heifer calving ease EPDs were calculated using a multi-trait animal model including birth weight and calving score data. The result is a heifer calving ease direct and heifer calving ease maternal EPD, as defined below.



•Calving Ease Direct (CED): Calving Ease Direct EPD is expressed as percentage of unassisted births, with a higher value indicating greater calving ease in first-calf heifers. It predicts the average difference in ease with which a sire's calves will be born when he is bred to first-calf heifers.

•Calving Ease Maternal (CEM): Calving Ease Maternal EPD is expressed in percentage unassisted births with a higher value indicating greater calving ease in first-calf daughters. It predicts the average ease with which a sire's daughters will calve as first calf heifers when compared to daughters of other sires.


http://www.angus.org/Nce/Documents/CedCemEpd.pdf





Fair enough, but how is a plus 14 better than a 0. Is it 14 percent less calving trouble, or something else?

Yes, on heifers.


Matter settled, now what to fight about. Finally raining here, first rain since the flood, it is good.






Did you need rain?
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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 10:37 am

[quote="df

Matter settled, now what to fight about. Finally raining here, first rain since the flood, it is good.





[/quote]

Did you need rain?[/quote]

Nearly 30 days since any significant rain, with 95 plus temps......you betcha.
Nothing like folks out west, grass was still green, but it was becoming a concern.
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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 10:44 am

df wrote:
Hilly wrote:
df wrote:

What do you mean by "breed to the average"?

Is the statement of "decreasing the variance" in conflict with MK's post on Pinebank, stating that Mother Nature will preserver variation?

What I meant by "breed to the average" is that in any gene pool if you use an outlier that possess favorable number for a unfixed trait odds are that over time they will breed closer to the average of all the cattle in that population, however they most likely will settle on the favorable side of center for that particular trait but of course that comes at a cost to another.

As far as Mike thoughts on variation, I agree... Mother Nature looks after maintaining a level of variation whether we like it or not and I wouldn't consider the reduction in variance of traits if it was not part of a bigger picture to restore her favor on the more systematic way  back to the end product.

If the bull has a good assortment of genes, and he passes them on at random, we would expect him to sire calves that perform better than a bull that gets a poor assortment of genes.

Let's assume a bull is 20 lbs larger than the average of the group at yearling. Due to the heritability of the trait, he is considered to be superior but less than 20 lbs; probably closer to 8 lbs greater. Once progeny of this bull are evaluated, his EPD has just as much chance of going up as going down. It is called the Best Linear Unbiased Prediction (BLUP). It is called unbiased as the EPD has the same chance of going up as going down.

The reason he appears to be to be breeding closer to the average may be due to heritability of the trait. If the heritability was 1, then his EPD could start a full 20 lbs greater than the average.


I think you two are speaking different languages.....completely different, like Latin and Navajo.
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Hilly



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 11:35 am

DF wrote:

If the bull has a good assortment of genes, and he passes them on at random, we would expect him to sire calves that perform better than a bull that gets a poor assortment of genes.

Let's assume a bull is 20 lbs larger than the average of the group at yearling. Due to the heritability of the trait, he is considered to be superior but less than 20 lbs; probably closer to 8 lbs greater. Once progeny of this bull are evaluated, his EPD has just as much chance of going up as going down. It is called the Best Linear Unbiased Prediction (BLUP). It is called unbiased as the EPD has the same chance of going up as going down.

The reason he appears to be to be breeding closer to the average may be due to heritability of the trait. If the heritability was 1, then his EPD could start a full 20 lbs greater than the average.

Again we seem to be back to the more easily measured performance traits and it still too complicated for my simple mind, and apparently I am not alone as progress in the quality of the end product since the invention of these EPD formulas is negligible at best, and to maintain these misunderstood higher numbers requires a move from outcrossing to crossbreeding which like it or not requires breeds.
I am new to the beef business, and for myself I would find it useful to have EPD paired up with the consequential  trait, for better understanding of the trade offs... Gains in production will come at the cost of energy required.

DF in your example the +20 bull what is the high and low range of his offspring to reach the+8....
For some reason this example reminds me of when I told an order buyer to purchase 300hd of 5 weight calves and I had just enough 7's and 3's to make a pen of 5's

DF do you think progress In trait fixation will be helped or hindered by isolation of the population?

Maybe Bootheel is right and we best start looking for translators as I fear I am only coherent in my own mind Smile
scratch
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df



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 12:01 pm

Do you mean "progress" in phenotype or genotype? Progress in phenotype, such as marbling, may have a lot to do with the feeding of starch (normally corn). If genotype is your interest, then EPDs can help move in that direction. As has been stated before, single trait selection will often come with unintended consequences.

Heritability has a lot to do with how quick you can make progress in a trait. For traits such as growth, the Angus breed has shown remarkable change in the last 20 years. How that has impacted fertility is less clear, although we can all guess.

If you want to make lots of change quickly, it can be faster to go to another breed. This is the route that several on this and other boards advocate. If you want more muscle and less fat, CH should get you there in one generation. If you want to have cattle that shed hair, maybe another breed could be beneficial.


The possible change in yearling EPD is about 15 lbs for low accuracy bulls about 68% of the time. That means 32% of the time the change could be bigger than that so once in a great while, you will see a bull move outside of the expected range.

http://www.angus.org/Nce/Accuracy.aspx

I don't know if weaning and yearling EPDs have a lot of value compared to other traits such marbling and fertility. Weaning weight and yearling weights are pretty visible. Marbling and fertility are harder to get a handle on and producers should benefit from EPDs on those traits.

EPDs have been paired with dollar amounts into bioeconomic indexes. Or you can find a correlation chart to help show the tradeoffs. The following chart is not very complete; you can probably google to find one more complete.

http://www.angus.org/Nce/Heritabilities.aspx

Trait fixation can be helped via linebreeding. However there are two things to think about. One is that fertility traits tend to be effected quicker than a reduction in weaning weight. With time I think this one can be overcome. The second thing is that a lot of the variation you see within a herd is not due to genetics. So even reducing genetic variation may not improve phenotypic variation very much. I also suspect it will take some serious inbreeding instead of mild linebreeding to have much effect. Oh and the third thing is that "type" may be under the contol of few genes as opposed to weaning weight which many consider to be under the influence of >100 genes. Thus, a herd may exhibit similar type but still have lots of variation in weaning weight.

Stacking EPDs that are similar will probably not reduce phenotypic variation very much as the underlying genes that make up that variation may be very different.

What I find interesting is the type called the "Ohlde" type. While it appears the type is somewhat "fixed", and it appears the EPDs have been "stacked", there are still bulls well outside the expected range. Ohlde bought those cows in 1986; how long will it take? I am not intimate with the herd so may be saying more than is real. But that is what I gather from looking at bulls in a sire summary and that are promoted by Angus breeders.





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Hilly



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 2:09 pm

I mean progress in consumer satisfaction and the ability to change with their changing demands,while maintaining a decent profit.

It has also been stated before that single trait selection is quicker on the way to being deemed fix then multiple trait selection and fixation.

I appreciate the attempt of the charts but I am more interested in the joules and the cost of those joules in a given plate of beef.

Fertility does take a hit during fixation as do other economically important traits... Nothing is free.

But to me if I attempt to step back as Larry has and look for a more  overall efficient way to " more regularly produce beef animals which at the lowest possible cost and expenditure of labour give the highest possible and longest lasting net returns

He goes on to say on page 5 of Reflections 

" Basically, I wanted to demonstrate how we tend to make the simple so complicated....but even moreso, I wanted to emphasize how we cannot fix an ideal if we cannot accept the limitations of any ideal...or breed, both being isolated populations."

When you state that much of the variation within a herd doesn't have to do with genetics... I couldn't agree more so why measure it and pretend it does?

If you practice as you say "serious inbreeding" I would guess the phenotypical variation will increase, but the principles stay the same.
And regardless of how many genes are in control of what traits the isolation and concentration of these genes will reduce the variance, but you have to keep in mind that more consternation we cause Mother Nature the less we can rely on traditional forms of measurement on the seed stock and reserve those forms of measurement for the cross.

You state that stacking EPD's or genes will not likely reduce variation in phenotype which of the two will better reduce variation in genotype?

As to how long it will take I would think that would depend on the number of traits your breeding for, but in multiple trait selection scenarios we are talking life times but that simple problem didn't deter Larry or Gavin and others before them, although you can see how running in circles gives the illusion of fleeting progress, moreso then slow, steady and more sustainable progress.

To me this makes simple sense and I realize my lack of experience is nothing short of laughable... But just consider me a mad experiment geek

Trying to keep up with DF via iPhone due to my down server is beginning to be quite frustrating... Sorry for the lag in response...
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df



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 2:57 pm

Hilly wrote:
I mean progress in consumer satisfaction and the ability to change with their changing demands,while maintaining a decent profit.

It is a commodity; some will make a profit and some won't. Unless you direct market and own your customers, which some have been successful at doing just that.

It has also been stated before that single trait selection is quicker on the way to being deemed fix then multiple trait selection and fixation.

Depends on the number of genes involved in the trait and how that trait impacts the fitness or ability to reproduce in that environment.

I appreciate the attempt of the charts but I am more interested in the joules and the cost of those joules in a given plate of beef.

$W and $B might be useful to you.

Fertility does take a hit during fixation as do other economically important traits... Nothing is free.

Depends on the heritability of those traits and correlations to the traits you are selecting for or against.


But to me if I attempt to
step back as Larry has and look for a more  overall efficient way to " more regularly produce beef animals which at the lowest possible cost and expenditure of labour give the highest possible and longest lasting net returns

He goes on to say on page 5 of Reflections 

" Basically, I wanted to demonstrate how we tend to make the simple so complicated....but even moreso, I wanted to emphasize how we cannot fix an ideal if we cannot accept the limitations of any ideal...or breed, both being isolated populations."

When you state that much of the variation within a herd doesn't have to do with genetics... I couldn't agree more so why measure it and pretend it does?

You can't change (accurately) what you don't measure (accurately).

If you practice as you say "serious inbreeding" I would guess the phenotypical variation will increase, but the principles stay the same.
And regardless of how many genes are in control of what traits the isolation and concentration of these genes will reduce the variance, but you have to keep in mind that more consternation we cause Mother Nature the less we can rely on traditional forms of measurement on the seed stock and reserve those forms of measurement for the cross.

You state that stacking EPD's or genes will not likely reduce variation in phenotype which of the two will better reduce variation in genotype?

If you know the genes, it would be easier to fix genes if you are able to use sires that are homozygous for those genes.

As to how long it will take I would think that would depend on the number of traits your breeding for, but in multiple trait selection scenarios we are talking life times but that simple problem didn't deter Larry or Gavin and others before them, although you can see how running in circles gives the illusion of fleeting progress, moreso then slow, steady and more sustainable progress.

To me this makes simple sense and I realize my lack of experience is nothing short of laughable... But just consider me a mad experiment geek

Trying to keep up with DF via iPhone due to my down server is beginning to be quite frustrating... Sorry for the lag in response...
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Hilly



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 3:49 pm

That’s probably been my problem all along I didn’t realize I was dealing with a commodity...Idea

I guess the relevance of the measurements to my operation as a commercial producer has more often than not be subpar at best and as you say in a commodity market that’s not good enough unless subsidized by the unenlightened or the taxpayer.

The more I read the more confused I am as to where you’re headed and what your goals are... Unless you are on a crusade to save a few lost souls, and if that’s the case I’ll forewarn you, rumour has it there is a one man wolf pack run lose here... or is it a coyote I forget Wink
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df



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 4:04 pm

This is a site about " a reflective and futuristic view of cattle breeding from outside the registered mainstream". One perspective does away with breed associations, EPDs and Indexes.

I don't intend to save anybody; just debating the pros and cons of genetic evaluations in making "progress" in the cattle business.
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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 6:20 pm

Quote :
If you practice as you say "serious inbreeding" I would guess the phenotypical variation will increase, but the principles stay the same.

If the environment remains the same then what would be the purpose of inbreeding if the phenotype never stabilizes? Would you only then just pick type and call it good?

Quote :
What I find interesting is the type called the "Ohlde" type. While it appears the type is somewhat "fixed", and it appears the EPDs have been "stacked", there are still bulls well outside the expected range. Ohlde bought those cows in 1986; how long will it take? I am not intimate with the herd so may be saying more than is real. But that is what I gather from looking at bulls in a sire summary and that are promoted by Angus breeders.

What interests you about the Ohlde type and what does it link to in function from your experience and education? Are the EPD's stacked or is the type stacked? As the cattle have been more inbred do you see greater range in phenotype or less?
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Hilly



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 8:28 pm

EddieM wrote:
Quote :
If you practice as you say "serious inbreeding" I would guess the phenotypical variation will increase, but the principles stay the same.

If the environment remains the same then what would be the purpose of inbreeding if the phenotype never stabilizes? Would you only then just pick type and call it good?

The purpose of inbreeding in my mind would ultimately be to stabilize the genotype, not the phenotype... but phenotype is where we all tend and maybe need to start before we close down, if only a portion, of a population and start the long journey to understand what we can’t see.

Type to type in a open population will also increase frequency of a more traditional and therefore marketable preferred visible type at the cost of some extra heterosis, but that would be more useful to me the commercial producer than crossbred or more outcrossed type, matings.

I think you can close a population, regulate management and environment as best you can and increase the frequency of a learned phenotype and I would suggest this would be a more true level, that often in my mind gets mistaken for regression and probably mimics levels found in local populations of wildlife, difference being we view there visible form as normal as they had a head start Smile

But if you wind it up more to the point of regression, not a onetime high IBC but actual regression from the production level you come to expect after 30, 40 years of a closed population with consistent pressure from the breeders eye, I would not be surprised if the phenotypical variation would increase as nature’s way of preserving her preferred variation levels...

Just a guess though and to venture in that far I would think foolish without intimate knowledge of the ancestry gain over decades of working with your closed population, as the resulting phenotype may not function at a normal level resulting in blind acceptance until after restoration.
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df



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 8:54 pm

EddieM wrote:
Quote :
If you practice as you say "serious inbreeding" I would guess the phenotypical variation will increase, but the principles stay the same.

If the environment remains the same then what would be the purpose of inbreeding if the phenotype never stabilizes? Would you only then just pick type and call it good?

Is the environment the same each year?


Quote :
What I find interesting is the type called the "Ohlde" type. While it appears the type is somewhat "fixed", and it appears the EPDs have been "stacked", there are still bulls well outside the expected range. Ohlde bought those cows in 1986; how long will it take? I am not intimate with the herd so may be saying more than is real. But that is what I gather from looking at bulls in a sire summary and that are promoted by Angus breeders.

What interests you about the Ohlde type and what does it link to in function from your experience and education? Are the EPD's stacked or is the type stacked? As the cattle have been more inbred do you see greater range in phenotype or less?


I suspect the type is stacked in certain lines although the Focus cattle are different, IMO. I think the EPDs have been stacked via linebreeding to specific animals. Probably intentional on both counts.

I think Ohlde cattle are interesting from the standpoint that many people seem to do well with them, as evidence that Ohlde is still in business and I would guess much of it is repeat business.

I don't think they work everywhere but have their place.
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MKeeney
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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 9:45 pm

df wrote:
EddieM wrote:
Quote :
If you practice as you say "serious inbreeding" I would guess the phenotypical variation will increase, but the principles stay the same.

If the environment remains the same then what would be the purpose of inbreeding if the phenotype never stabilizes? Would you only then just pick type and call it good?

Is the environment the same each year?


Quote :
What I find interesting is the type called the "Ohlde" type. While it appears the type is somewhat "fixed", and it appears the EPDs have been "stacked", there are still bulls well outside the expected range. Ohlde bought those cows in 1986; how long will it take? I am not intimate with the herd so may be saying more than is real. But that is what I gather from looking at bulls in a sire summary and that are promoted by Angus breeders.

What interests you about the Ohlde type and what does it link to in function from your experience and education? Are the EPD's stacked or is the type stacked? As the cattle have been more inbred do you see greater range in phenotype or less?


I suspect the type is stacked in certain lines although the Focus cattle are different, IMO. I think the EPDs have been stacked via linebreeding to specific animals. Probably intentional on both counts.

I think Ohlde cattle are interesting from the standpoint that many people seem to do well with them, as evidence that Ohlde is still in business and I would guess much of it is repeat business.

I don't think they work everywhere but have their place.
place or preference?
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MKeeney
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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 9:48 pm

Hilly wrote:
EddieM wrote:
Quote :
If you practice as you say "serious inbreeding" I would guess the phenotypical variation will increase, but the principles stay the same.

If the environment remains the same then what would be the purpose of inbreeding if the phenotype never stabilizes? Would you only then just pick type and call it good?

The purpose of inbreeding in my mind would ultimately be to stabilize the genotype, not the phenotype... but phenotype is where we all tend and maybe need to start before we close down, if only a portion, of a population and start the long journey to understand what we can’t see.

Type to type in a open population will also increase frequency of a more traditional and therefore marketable preferred visible type at the cost of some extra heterosis, but that would be more useful to me the commercial producer than crossbred or more outcrossed type, matings.

I think you can close a population, regulate management and environment as best you can and increase the frequency of a learned phenotype and I would suggest this would be a more true level, that often in my mind gets mistaken for regression and probably mimics levels found in local populations of wildlife, difference being we view there visible form as normal as they had a head start Smile

But if you wind it up more to the point of regression, not a onetime high IBC but actual regression from the production level you come to expect after 30, 40 years of a closed population with consistent pressure from the breeders eye, I would not be surprised if the phenotypical variation would increase as nature’s way of preserving her preferred variation levels...

Just a guess though and to venture in that far I would think foolish without intimate knowledge of the ancestry gain over decades of working with your closed population, as the resulting phenotype may not function at a normal level resulting in blind acceptance until after restoration.

four reads and I agree...GOOD STUFF...
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MikeJ



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PostSubject: Re: Direct vs maternal calving ease   Sat Jun 18, 2011 11:21 pm

.


Last edited by MikeJ on Sun Jun 19, 2011 11:38 pm; edited 1 time in total
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outsidethebox



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PostSubject: Re: Direct vs maternal calving ease   Sun Jun 19, 2011 6:54 am

So tell me what it means when, in my 10 years at this, I have never pulled or assisted a birth in any way yet when I have sent bull calves to central test stations they have performed well to extremely well?
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PostSubject: Re: Direct vs maternal calving ease   Sun Jun 19, 2011 7:27 am

outsidethebox wrote:
So tell me what it means when, in my 10 years at this, I have never pulled or assisted a birth in any way yet when I have sent bull calves to central test stations they have performed well to extremely well?

did you breed the 2400 lb gridmaker son to heifers Warren? Right off the top of my head, my answer is standard to those who never have any problems...you`ve just not had enough cattle yet...
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outsidethebox



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PostSubject: Re: Direct vs maternal calving ease   Sun Jun 19, 2011 8:20 am

MKeeney wrote:
outsidethebox wrote:
So tell me what it means when, in my 10 years at this, I have never pulled or assisted a birth in any way yet when I have sent bull calves to central test stations they have performed well to extremely well?

did you breed the 2400 lb gridmaker son to heifers Warren? Right off the top of my head, my answer is standard to those who never have any problems...you`ve just not had enough cattle yet...

That would be "no". And, otherwise, your "standard" answer is applicable.
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PostSubject: Re: Direct vs maternal calving ease   Sun Jun 19, 2011 8:29 am

outsidethebox wrote:
MKeeney wrote:
outsidethebox wrote:
So tell me what it means when, in my 10 years at this, I have never pulled or assisted a birth in any way yet when I have sent bull calves to central test stations they have performed well to extremely well?

did you breed the 2400 lb gridmaker son to heifers Warren? Right off the top of my head, my answer is standard to those who never have any problems...you`ve just not had enough cattle yet...

That would be "no". And, otherwise, your "standard" answer is applicable.
Smile
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PostSubject: Re: Direct vs maternal calving ease   Sun Jun 19, 2011 3:40 pm

Quote :
Type to type in an open population...
So if you close the herd will you either avoid or use type to type matings to achieve a line? I do not think that any EPDs, if they were available, would tell me anything since they are a remote spec of the entire breed population. With the combination of a closed population and type to type matings would I expect a full spectrum of variation such as 4 frame score range, 1.5X on the mature weight, slick to wooly coats and whatever else? Would this be my typical generation year after year? Would I not impose a type and selection level that would skew the general population to become more similar to my chosen type? If not, what is one of the purposesof seeking and recoginizing prepotency? Is your suggestion to hold out some ugly heifers and a misfit bull or two from each generation to hedge my bets? I do understand the underlying random gene pairing and hope of a fixed genotype without creating an inbred crash of the population.

Quote :
I don't think they work everywhere but have their place.
I still do not know what you think is the place for Ohlde cattle? Are you envisioning their place by type or by EPDs? What do the places where they do not seem to work tell you about their type and EPDs? And are their in-herd, fully OCC EPDs beneficial to consider or do the outcrossed individuals tell us more of the true EPDs of the avearage OCC animal?
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Hilly



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PostSubject: Re: Direct vs maternal calving ease   Sun Jun 19, 2011 6:34 pm

EddieM wrote:
Quote :
Type to type in an open population...
So if you close the herd will you either avoid or use type to type matings to achieve a line? I do not think that any EPDs, if they were available, would tell me anything since they are a remote spec of the entire breed population. With the combination of a closed population and type to type matings would I expect a full spectrum of variation such as 4 frame score range, 1.5X on the mature weight, slick to wooly coats and whatever else? Would this be my typical generation year after year? Would I not impose a type and selection level that would skew the general population to become more similar to my chosen type? If not, what is one of the purposesof seeking and recoginizing prepotency? Is your suggestion to hold out some ugly heifers and a misfit bull or two from each generation to hedge my bets? I do understand the underlying random gene pairing and hope of a fixed genotype without creating an inbred crash of the population.

Quote :
I don't think they work everywhere but have their place.
I still do not know what you think is the place for Ohlde cattle? Are you envisioning their place by type or by EPDs? What do the places where they do not seem to work tell you about their type and EPDs? And are their in-herd, fully OCC EPDs beneficial to consider or do the outcrossed individuals tell us more of the true EPDs of the avearage OCC animal?

If I close a portion of my herd for seed stock production that portion would be of the same type to begin with and most likely a preferred type for a purpose, keeping in my mind that a form will follow function and that form may run roughshod over my preconceived notions.

In my minds eye I visualize the approximate position of the original type to type open population that I am starting with as being right of center on the mating systems chart and guesstimated size of the sphere in the spherical distributions chart in an attempt to gain some perspective as to the amount of heterosis I am looking at.

Once the population has been closed down it will drift to the left towards a more homozygous state which may affect the visual appearance to some degree of the population as a whole.

So when you talk about your preferred type, I just think we need to acknowledge that it may be unreasonable to expect the closed population to compete in every way with the original cows due to the loss of heterosis.

I believe from what I have seen that there is a level here in and around center of the matting systems chart that a population can be maintained by eye, just maybe not the traditional eye, at a higher frequency of selected traits due to the constriction of the sphere toward that center… too high of expectations at this point will be unsustainable, but the ability to visually hold the herd from moving farther left and the closed population reducing the movement to the right, in my mind maintains a more natural balance.

At this level I don’t see the need to use your “misfits” but recognize that they may hold more inner order then outer.

Further movement to the left and further constriction... I start guessing, but through conversation with more experienced, I gather evaluation of the genotype at these levels has to be done with a restoration test, not by the golden eye Smile

Thinking back to Larry’s experiment with the three bulls the smaller wasn’t the smallest and the middle wasn’t the average of them all but the biggest was the biggest if I remember right and Larry didn’t credit much of the size difference between the bulls as being the difference in homo vs. hetero but that the smaller bull may have just been more central and therefore less disruptive to his pool or strain.

That shared experience I feel stresses the importance of an open mind as we gain familiarity and experience with the functional form we prefer.

Here is a quote from Larry I may have shared before
“Rather than worry about "homo/hetero" percentage content, selection would seem to be more like increasing the gene frequency for specific traits while reducing any interacting predominance of others. Of course the less variation we have to start with, the quicker the results. If you recall my spherical distribution analogy. we might assume that the center of a population would be the most "balanced". Over time I have been selectiing for the maternal qualities in moderate sized cows. Since Bonsma believed extremes disrupted functional efficiency, I could presume a beneficial side effect of my selection was a more balanced endocrine system resulting in stronger sexual distinction. Perhaps the smaller bulls were more "central" to the female genotypes of my preferred type ... less disruptive..”

I wanted to put this up as I don’t want to sound like I am stuck on the “homo/hetero” % as being the guide to gene frequency of certain traits but more of a bearing finder when I overlay my favorite spherical distribution chart that I’m trying very hard to spare everyone from posting again Rolling Eyes

I don’t think I’m doing a very good job of explaining what I am wondering about, sorry if I am making it worst…Embarassed
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Grassfarmer



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PostSubject: Re: Direct vs maternal calving ease   Sun Jun 19, 2011 8:02 pm

I don’t think I’m doing a very good job of explaining what I am wondering about, sorry if I am making it worst…

On the contrary I think you have an excellent way of explaining these concepts that are difficult to comprehend let alone explain to others.
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Hilly



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PostSubject: Re: Direct vs maternal calving ease   Sun Jun 19, 2011 10:09 pm

Iain,
I’m glad you find some coherence in it... I will never forget the feeling of clarity I found within an hour of meeting Larry for the first time, and the answers were as simple as I always believed they would be.

But when I try to explain the same simple principals it ends up sounding so complicated it’s frustrating, and I worry I am doing more damage than good.
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PostSubject: Re: Direct vs maternal calving ease   Sun Jun 19, 2011 10:48 pm

Hilly wrote:
Iain,
I’m glad you find some coherence in it... I will never forget the feeling of clarity I found within an hour of meeting Larry for the first time, and the answers were as simple as I always believed they would be.

But when I try to explain the same simple principals it ends up sounding so complicated it’s frustrating, and I worry I am doing more damage than good.

We're all different Craig.....just think how screwed up the world would be if everyone was like TomD, or me for that matter. We need some science types, with charts and graphs to balance out the rest of the freaks and geeks. Sometimes I don't get you, Sometimes I don't get myself, just keep hammering and collecting ears.


Bootheel

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RobertMac



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PostSubject: Re: Direct vs maternal calving ease   Mon Jun 20, 2011 9:22 am

If genotype is made more consistent, why would phenotypic variation increase?
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