What's wrong with chasing numbers?

[pdfangus]

Thought I would add that there are a lot of desirable traits that epds do not reflect or predict.

don't make a list or someone will start creating epd's for em.

[Third Row]

Has any association actually released the methodology used in calculating EPDs? I've tried on several occasions to find out (to model for an educational tool) but always came up blank.

[KNERSIE]

Has any association actually released the methodology used in calculating EPDs? I've tried on several occasions to find out (to model for an educational tool) but always came up blank.

Its probably considered intellectual property.

[3waycross]

Has any association actually released the methodology used in calculating EPDs? I've tried on several occasions to find out (to model for an educational tool) but always came up blank.

Its probably considered intellectual property.

Well I gues on any given day THAT would have to be considered an Oxymoron.

[alexfarms]

Has any association actually released the methodology used in calculating EPDs? I've tried on several occasions to find out (to model for an educational tool) but always came up blank.

I think the mathematics used to be written at the beginning of the old sire summaries, when they used to be in print. If you have access to any of the early APHA sire summaries I believe it would be in some of them. It used to be done by the University of Georgia, they may still be involved in it.

[bigag03]

The math behind the calculation is called BLUP (Best Linear Unbiased Prediction). It is a series of matrices that combine individual performance, parent performance, full and half sib performance, and most importantly, progeny performance. It is a weighted calculation where obviously, progeny data is the most heavily weighted. The larger the database is behind the data, the stronger the math is and the more reliable the predictions are (this is why Angus EPDs are the most reliable...there is more data).

The common misconception with EPD's is that they represent some given value (1.0 BW = 75 lbs)...NOT TRUE. The truth is that they only express the average of calves compared to the average of some other bull's calves. A set of EPD's by themselves mean nothing...they have to be compared to something (e.g. another bull or breed average). As the accuracy of an EPD increases, the variability in production never changes, but we become more confident in how that bull's average compares to others.

[WichitaLineMan]

>>As the accuracy of an EPD increases, the variability in production never changes, but we become more confident in how that bull's average compares to others.<<

Good post.