marbling and tenderness genes

[BRG]

I kind of agree with mntmn. I know that the average commercial man is already confused with all of these epds and figures we have now. Then we keep adding new ones all the time. I hate to admit it, but I don't really understand all of them myself. I don't really know what the outcome will be for single gene selection. But I have an idea it probably isn't a real good idea to do it either, just like you should never single trait select.

 

[MikeC]

Conclusion

PCR single-strand conformation polymorphism analysis of the calpastatin gene was not useful for prediction of calpastatin activity, myofibril fragmentation index, or meat tenderness. However, other studies have shown calpastatin activity to be highly related to meat tenderness. It is possible that other variations at the calpastatin locus could be used to predict calpastatin activity and meat tenderness in marker-assisted selection programs. In addition, at the molecular level, studies should focus on gene expression and marker typing in unrelated populations to evaluate candidate genes.


A link to the entire study:

http://ohioline.osu.edu/sc170/sc170_3.html

 

[dph]

Frankie:

Always like your posts. One thing I would point out. They were only using one marbling gene in their tests. I think as they add genes it will become a much better predictor. I think adding the second gene would improve its standing quite a bit should they run the test again.

I hear you about single trait selection. While marbling is single trait selection, isn't selecting for more and better meat on the rail the ultimate goal of all producers? Another concern is that in the Angus breed there is one predominant sire that is producing offspring that tests high in the GeneStar program. Gardens Prime Time will be found somewhere in almost every 9-10 star pedigree. It would be terrible if the focus comes on just a few bloodlines.

Mike, I will be honest. I didn't really understand your conclusion you posted. It was over my head. All I know is that breeders in the industry are constantly looking at trends and trying to sort out the fads. They also look at science and how it can help them improve their herds. Several breeders that have historically been the most adept at distinguishing trends from fads and implementing new uses for science in their program seem to be looking at gene testing. While we probably seldom realize the genetic potential for a given animal, the animal can't perform beyond his genetic potential. The whole focus of breeding has been to maximize the potential in the breed. I fail to see how genetic testing won't become paramount in that effort.

Help me out on carcass EPDs. I know Jeff Johnson of Summitcrest and Henry Bergfeld favored their marbling EPDs over IMF ultrasound results and they had the data to prove it. Their marbling EPDs are based on a huge number of carcass data from their own steers (i think they still lead the breed in carcass data collection), and recently their marbling EPDs for each steer were a better predictor of final marbling than the ultrasound IMFs on each steer that they had slaughtered. It's my understanding that based on the number of steers they harvested, they were pretty disappointed in how the ultrasound IMF data correlated to the actual marbling when harvested. They used two different ultrasound technicians, each with similar results. Does a breeder, like Summitcrest, with a huge ammount of carcass data, have more accurate carcass epds than the breeder who has no idea how their own steers are grading? Wouldn't collecting data on all those steers make their marbling EPDs extremely valuable?

Another breeder was commenting on how easy it was to change IMF results, he mentioned withholding feed, increasing their water intake, and others as ways to significantly change the how animals tested. He mentioned that actual IMF ultrasounds were only good to compare bulls within the group tested, and that even then there may be reasons other than marbling why a given bull may not test as well as one of his counterparts. Is this correct?

Learning a lot, thanks guys.

 

[OKJeanne]

We agree with those folks that say single trait selection
is a bad, bad, bad idea.

We simply require(first of all) that the seedstock animal
have the favorable tenderness genes(the known ones
at the time)....then we go down a checklist of other
things....but tenderness propensity is the first requirement;
not the only one. We have a couple of cows that have
perfect tenderness DNA scores that we use as recipients
because they are not built quite right.

 

[TSR]

Question: Even with 0 markers for tenderness, if I am selling sides of beef to independent consumers, why can't I just tell them to age the beef for a little longer. Doesn't aging in the cooler promote tenderness asthe beef goes through the natural deterioration process?

Marbling on the other hand, cannot be enhanced by the aging of beef, in my opinion, its either there or not.

Also when testing any breed for these genes, wouldn't one have to take into account the population of the specific breed being tested- greater the population the more that need to be tested in that particular breed to obtain accurate results. Especially when there is no randomness to the prior tests. jMHO

 

[thommoos]

With respect to marbling more often than not the more marble area the lower the average daily gain. Remember Fat weighs less than muscle, therefor when gaining weight the more muscle the more weight gain. if you want to find a good source for marbling and tenderness look at the ultra sound scores and research the Beef Cattle Improvement Test. I had a ADG bull of 4lbs. with a feed Eff of 5.69. but scored low in the fat area of only 1.83 while the top angus scored 3.22. So my beefmaster put on more weight with less feed which equals dollars at the feed lots. i raise beefmasters.

 

[andybob]

As more reasearch is done to map these genes,we are bound to find different genes affecting tenderness in different genotypes, for example, the same degree of tenderness in a Bos Indicus, British beef breed and a Sanga breed may well be totally different,complicating the selection criteria for the commercial beef producer with a crossbreeding programme.
The advantages, would be apparent when the heterosis effects come into play for the planned crossbreeding programme.

 

[clem]

8) I keep checking this thread, and it is so interesting, can't sort it all out, but, certainly a lot to think about, thanks for all the info, Clem! ( I've been waiting on a response from Dun, I respect his input), most of the other people whos' posts I enjoy have responded. Most people who do what we do are opinionated and stubborn, as I am, but this is not the place to show your a$$. This board is a good thing, but, lately, the petty BS is taking away from it! Lets treat each other the way we treat our cattle. ( Better thnan we've been treating our cattle) I HOPE! Wish your moms Happy Mothers Day, Clem :cboy:

 

[Frankie]

With respect to marbling more often than not the more marble area the lower the average daily gain. Remember Fat weighs less than muscle, therefor when gaining weight the more muscle the more weight gain.

I'd have to disagree with this. We send most of our bulls to performance test. Over the years some of the highest gaining bulls at test have also been high marbling bulls. B/R New Design 036 comes to mind. I've seen his sons gain over 5 lbs per day, over 3 for marbling, and reasonable backfat. We look for Angus bulls that will gain and marble.

if you want to find a good source for marbling and tenderness look at the ultra sound scores and research the Beef Cattle Improvement Test. I had a ADG bull of 4lbs. with a feed Eff of 5.69. but scored low in the fat area of only 1.83 while the top angus scored 3.22. So my beefmaster put on more weight with less feed which equals dollars at the feed lots. i raise beefmasters.

Feed efficiency of 5.69 is good. What were the off test weights of your bull and the top Angus? Where is the Beef Cattle Improvement Test? Are the results online? I'd like to look at them. Thanks....