cowboy_nyk said:
Gonewest - I'm not sure that you have been told the whole story. My father in law has been quite involved with the limo association and the development of the docility EPD. I assume the simmi and Angus numbers are derived the same way.
The EPD in no way relates to the raw subjective number that the producer assigns to each calf. The only effect on the EPD is from the in-herd index. That eliminates (to some extent anyway) the confusion between what a "1, 3, or 5" docility is. As long as a producer is consistent in his herd, the index value will be useful to determine if the animal is more/less docile than the average animal.
I'm sure you know much more about the Limousin Docility EPD model than I do. But two things about that breed are that when the idea for the docility EPD was hatched there was a tremendous need for it in that breed. The association determined the number one area for needed improvement within that breed was in disposition. And since there are/were a much higher percentage of "nuts" in that breed, there are many more of the higher number scored animals. It was/is easier to define. The Angus and Simmental breeds contain a much higher rate of animals with good temperaments. Just like in any EPD there is more variation between breeds than within breeds.
But I assume what you say is true about the Limousin EPD model being designed to reflect only in herd scoring. And because of the relatively small number of Limousin cattle registered the vast majority of those cattle are registered by a few individuals. That means the EPD's are shaped by a relatively few samples. And even so, the data is still subjective. For EPD's to truly be accurate the data that they reflect must be objective and from a large sample size. I would submit that the reason the Limousin breed has had so much success in addressing the temperament problem is that there was so much improvement available to be made. in other words there was lots of room for improvement. And that the amount of poor disposition in the breed was so easily identifiable.
If your Angus herd was really, really lacking in performance categories, in a few generations you could make tremendous progress toward improving that. But if you already had a top performing herd, you couldn't make the same amount of improvement a herd can that was poor performing. Likewise the Angus and Simmental breeds aren't able to make the same progress on temperament that the Limousin breed has because there is not the same amount of progress to be made. I would submit that the progress has been made in the Limousin breed because breeders decided to put emphasis on a trait that is easy to identify. Not because someone devised an accurate way to measure it by using a number.
I don't know of any Simmental bulls in heavy use that consistently produce temperament problems. In the 70's and 80's there certainly were. Lacombe Achilles is the first one that comes to mind. But because there is so little progress to be made in the overall breed and the fact that the data is subjective, I think this is just another useless EPD dreamed up to help justify ones job as it pertains to the Simmental breed.