| Autor: |
Crouse, John D., Dikeman, Michael E., Allen, Dell M. |
| Zdroj: |
Journal of Animal Science; February 1974, Vol. 38 Issue: 2 p264-270, 7p |
| Abstrakt: |
Visual appraisals of 452 slaughter steers of 14 breeding groups, representing a wide range in biological type, were made to evaluate criteria for characterizing body composition and carcass quality. Animals were fed and managed under the same conditions and independently evaluated before slaughter by three experienced appraisers. Steers were slaughtered in three groups after 215, 243 and 271 days on feed. U.S.D.A. quality and yield grades were determined on carcasses and the right side of each carcass was cut into semi-boneless, closely trimmed retail cuts. Correlation and regression analyses were used to determine the predictive value of live-animal traits studied.Carcass quality grade was more difficult to predict than carcass quantitative traits such as yield grade and percentage of retail product. Simple regression equations involving live-animal estimates of quality grades accounted for 13% of the variation in carcass quality grades on an overall subclass basis and 5% of the variation in carcass quality grades within breeds and slaughter groups. Addition of live-animal estimates of fat thickness improved the predictive value of the equation. Live-animal estimates of carcass yield grades accounted for 51 and 65% of the variation in carcass yield grade and percentage of actual cutability on an overall subclass basis. The accuracy of a developed equation, which included factors found in the U.S.D.A. yield grade equation, was improved (P < .05) by the addition of scores which estimated muscling. However, this improvement was small and the practical importance questionable. Live-animal estimates of the 12th rib fat thickness were found to be important in all carcass quantitative equations. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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