Epd's

[jnowack]

Mike the accuracies increase as more data for a particular trait is reported. The ratios for each trait are what the EPD's are derived from. Ratios that fall outside the expected range still count towards the accuracy beacause they will influence the actual EPD number. The other thing about the accuracy of the EPD is that is a common misconception is that it does not account for consistency. Two bulls could have an identical BW EPD and accuracy and one could have a much wider range of BW which would make him much less predictable.

I don't know how much the formulas or the models used for EPD's have changed or even how much the formulas vary between breeds. It sounds like the different models used to account for heterosis are using different values and I am sure they will continue to adjust these as they collect more data.

 

[Tod Dague]

Well, the ones that don't weigh within the parameters of the projected EPD's go against the accuracies of those being calculated.

Mike

Are you talking about the accuracy of the epd model that they are using or an individual animal's accuracy?

The "Accuracy Value" of EPD's.

At first they are called "Interim", correct? I presume this accuracy value is simply calculated by averaging the sire and dam. A guess, for lack of a better term.

As more data is input, they are actually are given an "Accuracy Value".

Is the model itself adjusted from time to time?

I presume it is, using figures derived from input data.

Sorry Mike, we were talking about 2 different things. ;-)

 

[auctionboy]

Weaning; Charolais 38.8 = Angus 0
Yearling ; Charolais 53.1 = Angus 0

Mike, am I reading this wrong? So, what is the Charolais epd going to be when an Angus has a yw of 90?

38.8 more than the Angus=128.8

If I am interpreting your question correctly.

That 128.8 should be 143.1
I have a question. What is the 0 yw for angus in actual pounds and where is that information?

I know we have argued about this before on these boards; but there is no actual hard and set value for 0. Depending on who has the cow in their herd and what they are doing with that calf a herd of 100 Anguses with 0 yearling wt. EPDs could AVG within a 400 lb actual wt swing easily. All the EPD is telling me is that typically if I had 50 calves with a YEPD of +100 in a drylot with 50 calves with a YEPD of +0 then at an adjusted 365 day wt the +100 calves should normally weigh on AVERAGE 200 lbs more (the EPD is the breeding value of the animal so you multiply that by 2 too get the PREDICTION of actual performance for that individual). If I had the same calves on good forage the +100 calves would definitely be bigger than the +0 calves. Theoretically, even there they would be +200 lbs heavier though as the level of nutrition declines the actual performance difference would also decline. The breed association can crunch the numbers and get an actual weight value for 0; but the odds of consistently repeating that number in a real world herd is so slight as to be a practically pointless exercise.

You say that crunching the numbers to get 0 is pointless because it is not very exact, isn't that the main principal behind epds (trying to crunch the numbers for a prediction?) What 0 is was very interseting to read, but has turned me of epds even further. I believe in them, but I wont ever use them exstinsively.

 

[Brandonm2]

Ok, you can get a REAL number for 0 or for +100 if you want it; but it does not mean diddly squat. Somebody with a 500 acre fescue ranch in Missourri where the cows get hay and a few range cubes has one level of production, somebody with 10000 acres in Montana who drylots his cows for five months has another level of production, a 50 acre heavily fertilized picturesque farm in Ohio that creep feeds and gives every momma cow 7 lbs of scientifically mixed ration every day has another level of production, somebody near Disneyworld with a year round fly problem 100 days of 95 degree heat, plenty of rain, but poor forage quality has yet another level of production. Even if they are ALL using 1407 on EXT daughters, you can expect a different weaning wt. on each place. REAL 0 is going too mean something entirely different on each farm. The EPD lets you compare two animals' genetic worth mathematically. Two bulls with an avg +50 difference in the YEPD should mean 50 lbs of difference per calf if both used on the same set of cows; but if I told you that the EPD gave you a calculation of EXACTLY what a set of calves should weigh on Joe Bob's ranch in Podunk West Virginia I would be greatly exaggeratng their real worth, especially if I used Frankie's 1977 zero number as my basis.

 

[Jogeephus]

Good thread. This is by far the most intelligent, honest and real discussion on EPD's I have heard in a long time.

 

[auctionboy]

Instead of what zero is I wanted to know what the average ww and yw of angus in the usa are? Just curious.

 

[MikeC]

http://www.angus.org/sireeval/ahir_ave.html

 

[Frankie]

Instead of what zero is I wanted to know what the average ww and yw of angus in the usa are? Just curious.

Maybe this is what you want? Actual weights?

"AHIR Average Adjusted Weights and Measurements by Year"

http://www.angus.org/sireeval/ahir_ave.html

 

[CowpokeJ]

So, if you had a choice.....Better than average bull with average epds or average bull with better than average epds?

 

[DOC HARRIS]

So, if you had a choice.....Better than average bull with average epds or average bull with better than average epds?

So, Cowpoke- not attempting to prolong this discussion any more than is necessary - however it is necessary for any debate or discussion to be operable, I feel that some basic understanding must be established in order to make the rhetoric comprehendible. When you asked the 'talking point' question, ". . . Better than average bull with average epd's or average bull with better than average epd's?" we must determine the definition of the words "AVERAGE and BETTER. "Better" than . . . .What? And "Average" compared to . .What? In making choices, one must have a pattern or template by which to contrast one with another.

In this thread - we are again 'dancing around' the need to LINK the application of EPD's WITH a thorough knowledge of PHENOTYPE! The two factors MUST be inextricably joined as a Gordian Knot in order to be functional and effective. One is weak without the strength of the other!

DOC HARRIS

 

[auctionboy]

650# weaning average on the angus bulls. Not a bad average.