CARCASS DATA ?

We sold a bull at the iowa beef expo and the scanned him. i was wonder if anyone could tell me what the numbers mean and weather they are good or bad. He had a back fat of .24 ribeye 17.3 marbling 5.08. He was a 22 month old bull weight 2034.

Seems like pretty good numbers to me. As I understand it scanning works best in contemporary groups. If you take 2 yearling bulls.......one has been on full feed since he was 2 months old.....and one was weaned on cane and off a cow on a saw dust and sand diet....you CANNOT compare the two especially on imf. Also feedlot cattle are put on a least cost ration not on a 2,000$ per hrad feeding regiment per head. I think this makes a difference on scan data.

My experience with carcass data (actual and ultrasound) has been on finished steers and heifers so that would be cattle in 11-1350 range and mostly 14-18 mos of age. In my uneducated interpretation of the data on your bull, it's best use would be compared to other 2 yo bulls on comparable rations and same breed as the previous poster stated. As a rule of thumb you would expect a market animal to have a REA of 1sq in per 100# body weight. If that holds true in breeding cattle then I would say your bull had less than average rib eye for his weight. As a 2yo I would say back fat would be determined by his diet and marbling by his age as much as by genetics in either category. I would think a scan at 12-18 mos of age be be more useful as a predictor of carcass traits of a bulls offspring. As I stated, just my 2 cents and by no means an expert opinion.

i haven't seen too many comments on rib eye area on older animals.  at what point does it stop growing with relation to weight/age

After a fairly extensive web search I can't find a source that says the correlation of REA to weight is any different for a 2000# animal than it is for a 1000# animal. REA is rarely measured on slaughter bulls/cows as their carcass quality is expressed in % lean. I guess that is why most of the scans you see on bulls takes place around yearling age (pretty sure that is when the carcass EPD's are measured) to get an idea of what kind of carcass his market offspring might have. Not sure how much value a scan of a 2 yo or older bull has other than comparison against other 2 yo's of similar breeding and diet.

So selecting for total ribeye could simply be selecting bigger cattle. |I would think rib eye per 100 wt would be the only data to consider?

aj said:

So selecting for total ribeye could simply be selecting bigger cattle. |I would think rib eye per 100 wt would be the only data to consider?

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good point.  ANd generally the larger the rib eye, the harder doing the animal is. Rib eye and marbling are also generally negatively correlated.

-XBAR- said:

aj said:

So selecting for total ribeye could simply be selecting bigger cattle. |I would think rib eye per 100 wt would be the only data to consider?

Click to expand...

good point.  ANd generally the larger the rib eye, the harder doing the animal is. Rib eye and marbling are also generally negatively correlated.

Click to expand...

Where is the data to back that up? Interested to know. I hadn't ever heard that. If it's true , then I would be happy with hard doing cattle, because I like my ribeye.

Doc said:

-XBAR- said:

aj said:

So selecting for total ribeye could simply be selecting bigger cattle. |I would think rib eye per 100 wt would be the only data to consider?

Click to expand...

good point.  ANd generally the larger the rib eye, the harder doing the animal is. Rib eye and marbling are also generally negatively correlated.

Click to expand...

Where is the data to back that up? Interested to know. I hadn't ever heard that. If it's true , then I would be happy with hard doing cattle, because I like my ribeye.

Click to expand...

I would like to see that data also  The breed I raise (Galloway)  typically has 1.5 to 2 inches of REA/CWT and is highly marbled.  Galloways are known to be very feed efficient cattle, and are not large framed.

From my SWAG (Scientific Wild Ass Guess), I have determined that your bull should have a Required Rib Eye Area (RREA) of about 19.4, this being that he has a Dressing Percentage(DP) of 64%(could be much lower).  Side note- DP only used to determine Hot Carcass Weight (HCW).  If he has a back fat level of 0.24 in gonna take a stab and say that he has a 0.50-0.60 fat thickness over the 10th rib.  All this being said if you got a Yield Grade on him he would be around a YG 5, which is pretty bad, even though he is not fat the REA he has really messes up the calculations.  AGAIN this is just a guess at some numbers with out looking at the actual sheet or the animal itself.  He would NOT get a quality grade, meaning he could not grade: Prime, Choice, Select, Standard, Commercial, Cutter or Canner.  Bulls CAN NOT quality grade in today's industry.  These are just my calculations I did off of my head making up some numbers off of the information given.  So to answer your question the numbers are not so hot on this bull.

Thank you. like i said i had never had one scanned and was just kinda wondering they mean. I noticed on the sheet of the shorthorn bulls they scanned not many had a ribeye over 17 and most had a marbling under 5.

Hey...I think you've gotten SOME true information here, and at the same time, I think there have been some comments that are pretty far-fetched. Yes...carcass data is obtained at or around the yearling age because that's when the information is meaningful. We market cattle around 13-14 months of age, so...

Also true, this information is not real helpful without a contemporary group to compare to. And 100 other Shorthorn bulls born the same day as yours on 100 other ranches do not make up a contemporary group! Cattle have to be within an age range of each other and born in the same herd, managed the same way until the data is taken, in order to be able to compare them to each other.

I think the folks at IBE are just taking advantage of technology to try and tell the breeders and the buyers as much as they can about the genetics that are being offered. It can be useful to identify outliers, both good and bad, but you really can't compare the data to other cattle in the sale...you can take it for what it's worth.

As far as the ribeye / square inch of body weight, this is true in general as an average for market cattle at market weights. Like somebody mentioned, I'm not sure it applies to a 2,000 lb Shorthorn bull...maybe it does, maybe it doesn't. I would have to agree that there probably is a point where that correlation levels out and maybe isn't really applicable. In general, the marbling score of 5 sounds relatively high...it would mean a lot more if you had 50 bulls in a contemporary group with scores below a 5, but take it for what it's worth. Especially if there weren't many cattle in the sale that were higher than that. Again...not direct contemporaries so you can't draw too many comparisons. And same thing with the REA, but you really can't compare his 17 inch ribeye to a yearling with a smaller eye and say that's proof that your bull is heavier muscled.

In general, heavier muscled cattle ARE less likely to marble. This is true across breeds as well as within breeds. Look at the difference between Angus and Limousin, for instance... Or any British breed compared to the continentals. And while this is true IN GENERAL, it is NOT the case automatically. There are lots of cattle who disprove that rule, and that's what breeding and selection are all about. It can be done, but it doesn't just happen.

Doc said:

-XBAR- said:

aj said:

So selecting for total ribeye could simply be selecting bigger cattle. |I would think rib eye per 100 wt would be the only data to consider?

Click to expand...

good point.  ANd generally the larger the rib eye, the harder doing the animal is. Rib eye and marbling are also generally negatively correlated.

Click to expand...

Where is the data to back that up? Interested to know. I hadn't ever heard that. If it's true , then I would be happy with hard doing cattle, because I like my ribeye.

Click to expand...

You should look into Holsteins, they meet your criteria perfectly.