First Pandiana - I do have confidence in gene marker testing. I agree that the ability to identify an actual gene is quite valuable. For example there are currently 2 tenderness gene tests available to industry. In combination the 2 genes seem to account for a large degree of differences in tenderness and they appear to act independently of influencing other traits.
I think the letpin test is useful, I don't however agree with the way it is being marketed as a solution to our marbling challenges. Leptin controls fat deposition, not marbling specifically, although it does provide a useful tool to manage feeding regimes. I am also pretty interested in how it relates to body condition, and fertility in cows because it controls fat, but no one has really gotten to the stage of investigating that yet, that I am aware of.
This leads to nerves question...
I think that homozygous TT cattle will in general put on more marbling with the same management as CC cattle. I also think that they will tend to give up some in the yield category. Depending on your market this may be good, bad or indifferent. I would like to see all breed associations collect as much marker data as possible on all markers and include it in their evaluations combined with field and research data. I know of a couple of breeds that are on the verge of doing this, and some that have used their research data to validate gene markers (basically using there data to prove that the gene actually impacts the trait it is advertised to impact). For example the American Simmental used their extensive shear force database to validate the tenderness genes for calpain and calpastatin.
not sure if this really answers your question. Obviously older cattle (eg: backgrounded then finished) should exhibit higher levels of marbling, however they should also produce larger carcasses. The key is going to be identifying what cattle do what things well, so that producers can mix and match to get the desired results.
I think the letpin test is useful, I don't however agree with the way it is being marketed as a solution to our marbling challenges. Leptin controls fat deposition, not marbling specifically, although it does provide a useful tool to manage feeding regimes. I am also pretty interested in how it relates to body condition, and fertility in cows because it controls fat, but no one has really gotten to the stage of investigating that yet, that I am aware of.
This leads to nerves question...
I think that homozygous TT cattle will in general put on more marbling with the same management as CC cattle. I also think that they will tend to give up some in the yield category. Depending on your market this may be good, bad or indifferent. I would like to see all breed associations collect as much marker data as possible on all markers and include it in their evaluations combined with field and research data. I know of a couple of breeds that are on the verge of doing this, and some that have used their research data to validate gene markers (basically using there data to prove that the gene actually impacts the trait it is advertised to impact). For example the American Simmental used their extensive shear force database to validate the tenderness genes for calpain and calpastatin.
not sure if this really answers your question. Obviously older cattle (eg: backgrounded then finished) should exhibit higher levels of marbling, however they should also produce larger carcasses. The key is going to be identifying what cattle do what things well, so that producers can mix and match to get the desired results.
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