DNA Studies of Meat Quality
a brief review about some genes controlling meat quality or grade in Canada
This webpage was last updated on June 28, 2006 by Sheila Schmutz email@example.com
|Canada grades beef primarily on the amount of marbling present within the steak. Ranchers try to breed for cattle of AAA or premium grade because they receive a payment bonus for delivering beef of such quality. Feeding is also important, of course, so that cattle are finished properly before slaughter. Marbling affects the flavor of the meat. It also adds juiciness, even when steaks are cooked well.|
One example of a gene that we found to affect carcass quality is leptin. Leptin is a hormone in the fat metabolism pathway that has been shown to affect the amount of fat deposition in beef. A DNA variant alters a critical amino acid which affects the folding of this hormone. The leaner cattle have a "C" and the more marbled cattle a "T" in the critical position. Therefore cattle are CC, CT or TT.
Leptin research began some years ago in our lab. Several cattle trials involving both purebred and crossbred cattle in several feeding situations have been conducted. Although the results vary in terms of the proportion that grade AAA or higher, the trend has always been the same: TT cattle have a much higher chance of AAA, or in the U.S. system "choice".
Because this T variant is inherited, a beef producer can try to purchase bulls that are TT and then know that every calf sired by such a bull will receive a T from him. The other allele of each calf obviously comes from its dam and so depending on the genotypes of the dams in the herd, calves could be TC or TT. Nevertheless the TT bull would ensure that all have a better chance of achieving a higher grade.
All of the cattle breeds that we have studied have both CC and TT animals. The proportion of these alleles does vary among breeds. The table below shows proportion of T in breeds where we have tested a sufficient number of purebreds to estimate this.
|Breed||Frequency of T variant||Proportion TT|
Articles in the Popular Press
....Who's the tenderest of them all? Western Producer, June 4, 1998. D'Arce McMillan.
Scientists Search Genes for Beef Tenderness,, Western Producer, March 16, 2000, p. 97. D'Arce McMillan.
DNA Research on Meat Quality. Cattlemen magazine, June/July 2001 issue. p. 18-19. Sheila Schmutz.
New DNA test could someday select sires for fat or lean. Cattlemen magazine, May 1999 issue. p. 20-21. Carolyn Fitzsimmons
A simple DNA test is available from Quantum Genetics 8 - 410 Downey Road, Innovation Place, Saskatoon, SK Canada S7N 4N1 306-956-2071 Fax: 306-956-2066
DNA can be collected from hair roots, blood, semen, milk, etc. It is marketed worldwide by Merial as Igenity-L.
for further information contact:
Department of Animal and Poultry Science
University of Saskatchewan
Saskatoon, Canada S7N 5A8
phone: (306)966-4153 fax: (306)966-4151