LEPTIN

[librarian]

https://www.animalsciencepublications.org/publications/jas/articles/81/1/1
Leptin as a predictor of carcass composition in beef cattle.
Geary TW1, McFadin EL, MacNeil MD, Grings EE, Short RE, Funston RN, Keisler DH.

I need help understanding this paper. The two groups of cattle were managed differently.
I can't figure out how this is related to the leptin concentrations and if the study implies whether management or genetics account for the differences.

 

[cbcr]

From some of our research, Leptin is something that can be detected by a DNA test.  It seems that that Leptin has to do with the marbling and tenderness.

From our understanding from Igenity, when they run the beef profile, they do test for Leptin, but it is not displayed in the results.

With the Igenity Profile test, for $5 the result can be displayed on the report.

There was a topic on here a while back started by AJ about the A2.  But there are also some information in that topic about the Leptin and also concerning the "Cheese Test" (Kappa Casein, Beta Casein and Beta Lactglobulin)  These also seem to have an effect as to the growth and performance as well.

 

[librarian]

In another post on SP, the question was ask about A2 milk.  We have been looking into all of these things.  We were first contacted by a Geneseek rep back in July of last year about offering what they call a dairy profile test to our members and the dairy industry which is a test primarily for crossbred dairy animals.  Part of that test includes what we are calling the cheese test which is the Kappa Casein, Beta Casein and Beta Lactoglobulin, and their is an A2 test which is separate.

These traits which deal with cheese, yogurt, and other products that are manufactured by the dairy industry, they also can have an impact of beef cattle growth, rate of gain, carcass quality.  There is one other trait that is tested for but not shown and that is Leptin.  Leptin has to do with carcass quality and tenderness.

After months of communication since July of last year, we were finally able the end of December to get pricing for these test.  We have ran some evaluation test just to see what the results would be.  These Cheese test and the A2 test are not breed specific, but some of the other traits in the GeneSeek Dairy Profile are.

That was from a previous post.
Are these blood tests, or hair sample tests?
How are these tests offered to members of your registry and how are the results a available for comparison?

 

[cbcr]

The test can be either done with blood samples or hair samples.

We need to update our beef website, but the order form is on our dairy website.  Composite Dairy Cattle Registry www.dairycattleregistry.com and the actual link to the order form is http://dairycattleregistry.com/forms/igenity_submission_form.pdf.  Their is also a spreadsheet that owners can use to enter the information in that is also available.  It is on our Fees and Forms page under the Igenity order forms.

The test is available to anyone, their is no difference in price for our members vs non-members.  The prices are what Igenity/GeneSeek charges.

For beef producers, their is the Igenity Profile with covers about 12 or so traits ($40), a Beef Heifer Profile ($22), the Dairy Profile-CB ($30).  To have the Leptin test results displayed is ($5) and the A2 test is ($12).

The results can be emailed, mailed or faxed to the owners, if the A2 test is done, that test takes a few days longer.

If anyone does have any questions concerning the tests, they can give us a call 816-738-4179

 

[cbcr]

An article came out today on the Drovers Cattle Network titled "Marbling research shows healthy fat in beef has benefits", http://www.cattlenetwork.com/news/industry/marbling-research-shows-healthy-fat-beef-has-benefits

What was discovered is that cattle that marbled higher had increased Lipid (another term for intramuscular fat).

With this in mind and having read and researched about the Leptin gene, we tried to find our what is the relationship between Lipid and Leptin.  Unable to find a good definition, we called and visited with Dr. Stephen Smith, a Texas A&M AgriLife Research scientist and Regents Professor in the department of animal science at Texas A&M University, one of the researchers.

In conversation with him, he said that Lipid is the fat deposit where Leptin is in a marker in the gene makeup (DNA).  He did say that while their is a great difference between the two, the only comparison that can be made is that animals and carcasses that show and test higher for Lipid would also show to have a higher score on a Leptin marker test.  But, he emphasized that is about the best way to describe it,  and is as close as they are related.

When it comes to testing for cattle to find the so-called "magic bullet" when it comes to the pre-potency for cattle to marble or how well they will marble, their is none.  In his comments he said that in their study as is mentioned in the article is that the Waygu tend to keep marbeling where an Angus animal seems to plateau at somewhere around 20 months of age and at that time just puts on more external fat and then other breeds, mainly the continental breeds have a harder time with the levels of Lipid "intramuscular fat".  One reason why a crossbred animal of English / Continental is a good animals is because the Continental has a tendency towards better muscling and the English breeds have a tendency towards more fat.

As was mentioned, their is no "magic-bullet", and researchers have been trying for over 25 years to find one.  As our technology improves we will probably get closer.

In looking at research that has been done in the past and recently, their is probably more interconnection between genetic markers working together for animals that perform and finish better.

As we have posted before, Geneseek has the Beef Profile and on the dairy side they have the Dairy Crossbred Profile which included in the Dairy Profile is a test for the Kappa Casein, Beta Casein and Beta Lactoglobulin, and this test can also be used for beef cattle.  A separate test is available for the A2.  The presence for Leptin can be done for an additional cost.

Genomics are here to stay, whether we like them or not.  It is one of those things that if more producers were to become involved in their use, then the technology, accuracy and value of these would also improve.  Along with this, better test could be created.

Links to these test on our beef website Composite Beef Cattle Registry www.compositebeef.com and on our Composite Dairy Cattle Registry www.dairycattleregistry.com is under the fees and forms link.