How are Angus EPD's established?

[Cormac]

Been looking at Bulls lately. Low birth weight is very important to me. Growth is important, as is Milk. If a young bull has never produced offspring, how do they arrive at numbers? Do they initially simply average the parents EPD's? I ask this after looking at a bull whose sire had a birth weight of 3.9 and the dam had -.2. This bull is listed with a BW of .3. This would be right in line with what I am looking for if it was accurate. What I do not want is a close to 4 BW bull. BW accuracy numbers listed .36.

 

[Scotty]

http://www.angus.org/sireeval/accuracy.htm When you get here read. It will be easier for you. But your right. 1st or interem come from an average of the parents. 2nd is from the bull idividual performance (unless he was an embrio transfer) then 3rd it is from his offspring.

 

[Aero]

Scotty:

ET calves can be factored in if out of a registered recip.

the basic process is:

1. average out the parental EPDs (BW EPD: 3.9 + -.2 = 3.7 / 2 = +1.9)
Accuracy will be .05

2. if the calf has a high or low ratio, the EPD will move that direction (he must have ratioed pretty low for birth weight, so his EPD came down quite a bit to +.3
Accuracy will be in the .25 - .36 range unless he is an ET calf out of a comm recip

3. with his first calf crop, the ratio of his calf crop compared to others will move his EPDs up or down.
50 calves will get Acc up to .50 - .70

*this isnt very precise and there are some other small factors, but it is basically right

 

[Cormac]

The above referenced bull has never sired offspring so who comes up with the initial numbers listed in the Angus EPD's, The Angus Assoc. or the breeder of the bull. If it is the breeder, isn't there temptation for some to "fudge" numbers. To come up with the BW listed, it certainly is not the average of the Sire and dam (3.9 and .2). With my math it averages 2.05 not .3

 

[dun]

Personally, I'm leery of any BW in the frist several generations that could cause a train wreck. Breeding 2 extremes won;t give you a trueaverage ver time. They will tend towards one side or the other of the extreme.

dun

 

[Frankie]

The above referenced bull has never sired offspring so who comes up with the initial numbers listed in the Angus EPD's, The Angus Assoc. or the breeder of the bull. If it is the breeder, isn't there temptation for some to "fudge" numbers. To come up with the BW listed, it certainly is not the average of the Sire and dam (3.9 and .2). With my math it averages 2.05 not .3

Accuracies also reflect any data available on siblings, aunts, uncles, etc, of the animal. If his sire is, for example, EXT, then he has thousands of half sibs on record. If his dam is, for example, a 602C cow, there'll be hundreds of records there, too. All the data from those half sibs, cousins, etc., will go into creating his EPDs, along with his own performance.