 |
||||
|
||||
|
|
||||
Color and ossification, or bone hardness, are the two factors used by the USDA to determine the maturity of a carcass. A West Texas A&M University researcher said it may be time to look at the system again. Dr. Ted H. Montgomery, a meat scientist at WTAMU, said the system has been in place for 75 years. It depends on a meat grader's judgment as the carcass moves along the chain. Montgomery said a better way may be with dentition, or using the animal's teeth to determine age. At the very least, it is a more objective measurement, he said. Montgomery found during research, using Mexican cattle in a panhandle feedyard and dentition, cattle which had a wide age range were still being given an A-maturity rating. "This was really startling to me," Montgomery said. "If the dentition means anything, these cattle are 36 months of age. We say that A-maturity cattle go from nine months to 30 months. These cattle were over the line." This means the industry is putting some very old cattle into the mix and is still classifying them as A-maturity. "This has to add a lot of variability to the mix as far as those cattle are concerned," Montgomery said. Overall, he said, there was a decline in A-maturity cattle and an increase in C-maturity cattle. Many of these cattle were not eligible for Choice Grade, yet they were probably under 36 months of age. These cattle were clearly older than the intended maximum for Choice and added variability to the population, he said. Researchers have compared USDA maturity scores to Wamer-Bratzier shear force values and taste panel tenderness evaluations. The results vary from no relationship to a highly significant one. Many found no relationship between maturity and tenderness and a few found no differences in shear force value or taste panel tenderness when looking at A and B maturity classes. A 1974 study discovered small tenderness differences in the loin between A and B maturity groups and concluded tenderness was not related to advancing physiological maturity. That study also determined the separation between B and C maturity groups could not be justified on the basis of tenderness. A 1983 study showed maturity classes A, B, C, and D had no effect on sensory properties or shear force values of the loin area. A 1998 study found no significant correlation between tenderness and skeletal or overall maturity of the loin area. Several studies in the 1960's had mixed reports on the relationship between maturity and tenderness. One study found USDA maturity scores had an insignificant effect on loin tenderness, however, steaks from less mature carcasses were preferred by a taste panel evaluation. Today, researchers are finding inadequacies in grading systems where maturity is determined by the evidence of skeletal ossification, lean texture and color. While there are conflicting conclusions relating carcass maturity to tenderness and palatability in several studies, Montgomery speculated the major factor relating to these disagreements is the subjectivity of the USDA maturity scoring system. When the standards were developed in the early 1920's, the thought of using dentition may have never been considered since all grading was performed after the carcass was chilled. At that point the grader had only one means of scoring maturity -- ossification. Over the next seven decades the subjectivity of scoring maturity by ossification has remained. The subjectivity of the system can be accounted for through USDA guidelines for determining skeletal maturity. The lines between maturity are not distinct and many graders making these subjective calls have their own opinions about where the maturity class lines should be. Normally, Montgomery said there are given time frames in the chronological age of cattle to the eruption of the permanent incisors. However, contrary to Montgomery's data, a 1991 study concluded that the number of permanent incisors is not a reliable source to indicate chronological age. Further research is needed to know for sure. |
||||
|
|
||||
|
|
||||
|
All information is copywrited by Feed Lot magazine and cannot be printed or re-printed
without the publishers express consent. Please contact
Feed Lot Magazine for reprint and copy authorization.
|
||||