When we get our bulls scanned, it takes about 2 weeks for the lab to interpret results and then send them to the association. Ours is the IBBA. Bulls are developed in so many different ways, I say go with the EPDs. ie. Breeders that creep can wean calves at 800#+...doesn't take long to get them to 1300#+ yearling with lots of IMF because they've been on grain pretty much their whole life. We prefer not to creep, let the cow do the work, then develop on a limited ration with forage as a major component. If they're the same genetics, how important is that actual data, especially when comparing cattle from different operations and different contemporary groups? You see a lot of AI sires with actual measurements that don't match their EPD's, and over time their calves increasingly prove those EPDs to be true. There are a few high accuracy low birthweight bulls in the breed who were anything but, themselves. Brad Wright has had a few interesting articles on this topic in the last several issues of The Ear.
I think the next "big thing" is genetically-enhanced EPDs. Basically provides the accuracy of an entire calf crop with a DNA test. We tried it for the first time on a group of virgin bulls a few months ago and had some surprising shifts. It will definitely help with peace of mind when selling bulls for heifers.
Can't speak on Herefords, other than my impression that carcass data doesn't seem too important to them. ??
