EPDs are great tools to cull potential animals, extremes and types that you do not want to use. They can be good tools to select a group of potential animals for possible use. Two words that get confused are precision and accuracy.
The buzzword for most on EPDs is accuracy which is built on numbers of observations or weights to give us the picture of what the average offspring might be like from X bull or Y cow. But if we buy clothes and dress for the average temperature of the place we live we will be hot 49.5% of the year, cold 49.5% of the year and comfortable 1% of the year. Precision is how closely the range can be narrowed, much like the year-round balmy breezes on a sea island with minimal temperature variations. (Old term = cookie cutter)
So, how do we deal with precision? One is breeder integrity: did the breeder have the internal fortitude to breed the potentially great new bull to average cows in the first year or did they cherry pick? Were the weights, observations and measurements correct? How many potential half sibs that looked bad or performed poorly were not reported? Often, bad EPDs are human problems and not cattle problems.
How widely the close genetics have been used in the main population of the breed is as big. We have a fairly closed herd and it is amazing how poorly particular EPDs represent the function of the individuals. In situations like these, the breeder's familiarity and recommendations and the viewing of functional traits and actual data wins out hands down. That must be where this Hereford bull falls.
The other thing that bothers me is the fallout rates on mainstream sires that I have used. I waited for them to get plenty of "accuracy" on things like HP and yet the fallout rate for daughters is too high for the numbers to be precise or accurate.
But the most deceitful and devious issue is not traits potentially represented by EPDs but the obvious faults that have to be known on proven sires, lines and families. I just shipped a 5 YO daughter of a highly proven AI bull that is late bred and calves like clockwork. Her feet look like clown slippers and her calves could be used to recreate miniature wooly mammoths. I tossed out the rest of that semen when I saw her feet as a springing 2 YO. Temperament, feet, legs, stifles, adequate SC and what else really makes a cow herd besides EPDs? Give me good traits and I can live and work on things related to EPDs.