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Originally Posted by DJ in WA
Reading other sites, I've heard comments that EPD's (expected progeny difference) numbers can be fudged. And in the thread on dairy bull disposition, sounded like AI companies were reluctant to consider temperament, even though it could ruin a herd.
So, do you trust numbers on bulls? Is there any outside verification of those numbers? Where do they get the data? From breeders own herds, or from people they've sold the semen to?
Just wondering if AI companies always have the end producers interests in mind.
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I'll only address the dairy bull side of things, as that's what I work with, and OxAnkle is doing a fine job of explaining the beef end of things.
On Temperament, it is not a factor north American Bull Studs(Companies) study or compile data on. The NZ Companies do. They call it Shed Temp - Which translated means Milking Shed(Parlor) Temperament. For example, on a bull proof for Sanrosa Royal Paul, on a scale of negative 1.0 to positive 1.0, he is rated a positive 0.2, which means they will "probably" be reasonable cows to work with. We have 7 of his daughters milking, and this assessment has proven accurate.
In the US Dairy industry, bull studs compile the numbers thru records from DHIA Testing and records from the Classification of a bull's daughters. This is done in actual working herds the studs have sold their semen to. Classification is a process whereby a qualified professional travels to a farm, evaluates a bull's daughters by comparing them to an ideal template, and then records their scores on a whole host of measurements.
By and Large, My Opinion would be that the system has integrity.
" So Do You Trust the Numbers?"---Yes, but you need to evaluate them based on the amount of repetition of data to support them.
To illustrate, I'll use examples.
From Select Sires, they have a fairly new Bull named 7H7463 Pontiac. His pedigree is DurhamXEmoryX Value, so one would expect reasonably good stock as they were good bulls. When we look at the Type Data compiled, it shows data came from 70 classified daughters.
Then we look at another Bull that has been around longer 7H5708 Blitz, whose Pedigree reads EmoryX Tesk with Blackstar in the Background. Again respectable Bulls, so one would expect good stock. However, his type data is compiled from 4,053 classified daughters.
So logic would lead to conclusion that the "data" would be MORE reliable, hence more trustworthy on the second bull.
Hope all this helps.