Variation - bell shaped curve

Bob H wrote:

Mike I would not know but Larry would the conversation that I have with him is I need bulls that will keep me in bussiness. I suspect that by useing multiple sire's from Shoshone on a volume of cows would be one of the adavantages that we enjoy. Larry should be watching and maybe will comment .

I`m teasing Larry a little Bob, and jerking a little at those who believe a 60 day calving season improves genetic fertility...readily admtting, it can`t hurt anything but the wallet

I guess Larry knows what he's doing, but 6 60 day calving seasons -- he might as well just breed year-round.
Geniuses are hard to understand,I guess.

I'm probably a idiot, but if a cow was in heat on the 65 day wouldn't it have been beneficial to have the bull in the pasture rather than having to replace her. I don't preg check, don't pull the bull till the cows start calving and calved out in 36 day except for 1 which calved on day 64 or 28 days behind the second to last one. Of coarse I'm also not on range land and on most years the cows have very good grass at turn out. If they were stressed I may have some opens. I think fertility is related to my management rather than my genetics, but I'm also not going to change management to test it.

this is pretty tongue in cheek stuff about the 6 times 60...kinda a joke bewteen LL and I...Shoshone Angus is not always where the college kids taking Livestock Management 101 would need to go; cows are seldom the priority...neither is Keeney Angus...Larry`s reason is time; my excuse is time

Why are y'all wasting so much time on "one point" on a bell curve when it says nothing about the variation of the data used to derive the "one point"?

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Why are y'all wasting so much time on "one point" on a bell curve when it says nothing about the variation of the data used to derive the "one point"?

Robert, tell us where we've failed and we might act like we will repent.

let's try this as a beginning postulate...

The range of variation that can occur is the square root of the heterozygous alleles at all of the individual loci that determine a particular trait...

discuss, add or correct as you see fit...

What in an epd tells us the range of variation?
How are environmental effects taken into account?
Would not a change in environment skew the epd and increase variation?
Would not epds be most useful in a herd that has been closed for many generations?
Aren't epds used more as a marketing tool rather than a breeding tool?
A lack of data makes epds rather useless in my breed, which probably explains my attitude!

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What in an epd tells us the range of variation?

The accuracy.

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How are environmental effects taken into account?

The ones that stay alive on your farm are the best.

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Would not a change in environment skew the epd and increase variation?

Math is math. Survival is for the fittest unless you prop them up.

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Would not epds be most useful in a herd that has been closed for many generations?

Ony for your herd. They will get less connected to the outside portion of the breed over time.

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Aren't epds used more as a marketing tool rather than a breeding tool?

It depends on whether you are a marketer or a breeder.

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A lack of data makes epds rather useless in my breed, which probably explains my attitude!

Without data you would have low accuracy to compare to the general population. If you do not have data why are you worried about other folk's EPDs?

EddieM wrote:

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What in an epd tells us the range of variation?

The accuracy.

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How are environmental effects taken into account?

The ones that stay alive on your farm are the best.

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Would not a change in environment skew the epd and increase variation?

Math is math. Survival is for the fittest unless you prop them up.

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Would not epds be most useful in a herd that has been closed for many generations?

Ony for your herd. They will get less connected to the outside portion of the breed over time.

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Aren't epds used more as a marketing tool rather than a breeding tool?

It depends on whether you are a marketer or a breeder.

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A lack of data makes epds rather useless in my breed, which probably explains my attitude!

Without data you would have low accuracy to compare to the general population. If you do not have data why are you worried about other folk's EPDs?

I agree fully except for point one...accuracy merely pertains to the accuracy of the average, not the range of the variation...

MKeeney wrote:

EddieM wrote:

. If you do not have data why are you worried about other folk's EPDs? Good question...must be my Scottish heritage that makes me argumentative.

I agree fully except for point one...accuracy merely pertains to the accuracy of the average, not the range of the variation...

The average of 10 numbers is much more likely to change than the average of 1000 numbers...simple math. The larger the data field the more stable the average of the data field will be...that is epd accuracy.

epd with variation

animal 1...YW +50;+or-5 lbs
animal 2...YW +50;+or-20 lbs.

I think I agree ... I need a cup of coffee!

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I agree fully except for point one...accuracy merely pertains to the accuracy of the average, not the range of the variation

Maybe I have missed more than I know about, but if an animal gains more accuracy, just use BW EPDs and instead of the expected +2 BW before proof, his offspring prove that he is more accuately a -2:

Is there absolutely no change in the range of variation on BW?
Does the bell curve move to the left?
Does the bell curve hold a fixed base width and grow taller?

P. S. I'm dangerous after a couple of cups of coffee!

6,6,4,4,2,2 ,0,0...average 3.... and has more accuracy than....
6,4,2,0 average 3....
that`s the extent of the use of accuracy...

In reality, do "curve benders" bend the curve, or straighten it- due to increased variation?

Keystone wrote:

In reality, do "curve benders" bend the curve, or straighten it- due to increased variation?

hmmmm...any curve bender has at least two traits that can move either way....hmmmm...i guess straighten it...
a little off thread here...another "data set"...beef sales determined by the groceries selling all their hamburger buns over the 4th weekend

Better than expected clearance of beef over last weekend, spurred cattle futures and raised asking prices from cattle owners. Packers are attempting to purchase cattle at steady money to last week but most sellers raised asking prices to $116. THE CATTLE REPORT reported early week that many locations were sold out of hamburger buns last weekend. The actual clearance numbers were confirmed with many stores reporting better than expected sales of beef over the weekend.

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6,6,4,4,2,2 ,0,0...average 3.... and has more accuracy than....
6,4,2,0 average 3....
that`s the extent of the use of accuracy...

What about a young unproven animal with a low accuarcy +2 on BW based on parents so no data like 6,6,4,4,2,2,0,0 available. Then the data does come in: 6,2,2,1,0,0,0,-2,-1,-2,-5. Do I not see a shift of the curve?

What if data is 1,0,-1,-1,-1,-2,-2,-2,-2 and it stays in a smaller range? Is this one of the roles of linebreeding or can it be accomplished by type breeding?

I'm not needing to argue, I just am trying to see if there is a way to determine a control of range of values and understand accuarcy vs changes in the expected.

Where's df when you need him?