Ultrasounding

[strojanherefords]

In another thread, ultrasound protocols were briefly discussed, but I think further discussion of the subject is warranted. My concern is that type of cattle that are scanned are different than steers on the rail.  Two bulls that would have produced identical carcasses as steers might have different scans had they been left intact due to differing levels of testosterone.

[timbernt]

My question is how meaningful the data is if the scanned animals are not "finished". After all, we are trying to establish what the carcass of a slaughter ready animal looks like. If we are looking at ultrasound data on an animal whose nutritional status is not 120 to 150 days of high energy feed do we really get meaningful data? Or, are we simply getting haphazard statistics to use in a marketing program? I am not trying to belittle those willing to go the extra mile to collect that data. I am trying to figure out if I should be directing some of my limited resources toward carcass ultrasound.

[shumakerherefords]

Don't know what others are scanning for. In my case I am trying to determine the genetics that will produce superior feedlot carcasses and profit. Now I only keep about 3 bulls each year and use the best performers so I don't have much scan data to compare to the feedlot steer carcass performance. I do keep about half the heifers till yearling. What I have learned over the years is that you have to feed them enough to allow them to express their genetic potential for REA and IMF. That is treading a fine line of not getting them too fat which depends a lot on how severe the winter weather is. The last couple of years I have managed to keep the rib fat below 0.20 with REA/cwt of 1.03 and IMFs of 3.5 to 4.25.

The cull heifers that go to the feedlot (over 90 lb birth weight or less than 95 WW Ratio) will usually grade 90 to 100% choice. The steers typically grade 75% choice or better. www.shumakerherefords.com/smfeedlot.html

The point about testosterone is interesting and certainly deserves study. Would suspect that if there is a correlation there would be an inverse relation to scrotal circumference.

[larso]

Good point Tim, I scan all my bulls that I'm selling or keeping for myself plus all the heifers regardless but they are all on a level playing field. To me as long as they are all on the same nutritional plane and diet there is no problem. Diet can effect REA,IMF and frame score and IMO this is the flaw that EBV's have, there is no way environmental differences can be calculated so once again "Bullsh.t goes in Bullsh.t comes out"

[kph]

It's certainly not a perfect system, especially when you consider the apparent differences in results from different technicians and see the allowable margins for error in data. The best data is always going to be finished hanging carcasses. I've been scanning for a few years now still think it's a good thing to do, but probably not as a "snapshot" of your cattle by just doing a few good bull calves. The larger the contemporary groups you can do the better and stick with it several years to identify trends. I DEFINATELY would recommend doing all replacement heifers if you are actually trying to make any improvement in your herd. It does get to be some sticker shock when you are doing 50 head or more, so it would be nice if they could come up with a more reliable way of doing it.

[strojanherefords]

Is there a formula to estimate the pounds of beef on the hoof from a live weights and scan data?

[shumakerherefords]

Interesting question. I have not seen the equation you are asking for. You might develop your own from this link: www.sdstate.edu/ars/students/activities/judging/evaluation/beef-grading.cfm

What you seem to be asking for is the dressing percent x live weight. Dressing percent normally runs from 60 to 64% but I have seen some outliers as low as 57% to as high as 66%.

However that could be misleading on the normal scans of yearling bulls and heifers that have not been pushed as hard as feedlot cattle.