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D Hixon

Publications and source records attributed to D Hixon.

3 recordsLinked to original sources
PubMed1997

Tenderness variation among loin steaks from A and C maturity carcasses of heifers similar in chronological age.

Fifty-two Angus x Gelbvieh rotationally crossed virgin, ovariectomized, or single-calf heifers were slaughtered after 100 d on a high-concentrate diet. Heifers from each treatment were approximately 31, 33, or 35 mo of age, and they produced 31 A, 5 B, and 16 C maturity carcasses. Because of the small number, B maturity carcasses were not included in this study. Number of A maturity carcasses decreased as age increased. No differences (P > .05) in slaughter weight, total weight gain, dressing percentage, longissimus muscle area, or kidney fat percentage existed between carcass maturity groups, but C maturity heifers had 3.56 mm more fat (P < .01) over the longissimus muscle than A maturity heifers. Marbling scores of slight79 and small0 for A and C maturity carcasses, respectively, did not differ (P > .05). The A and C maturity heifers had similar amounts of collagen and hydroxylysyl-pyridinium crosslinks in metacarpal bone cortex and in longissimus muscle. Neither means for panel tenderness nor Warner-Bratzler shear values differed (P > .05) between maturity groups. Coefficients of variation for tenderness were slightly higher in steaks from C maturity carcasses, but CV for shear values between A and C maturity groups were similar. Because inconsistent meat tenderness is a recognized problem in the beef industry, more research on tenderness variability within maturity and marbling groups is needed. This information, in addition to pooled SEM and differences between means, should aid in finding ways to reduce beef tenderness variability.

Aging↗
PubMed1996

Growth, carcass, and tenderness characteristics of virgin, spayed, and single-calf heifers.

Fifty-three Angus/Gelbvieh rotationally crossed heifers were slaughtered after 100 d on a high-concentrate diet. The average slaughter age for each of three different groups was 31, 33, or 35 mo, which falls within the USDA's 30- to 42-mo age range for animals producing "B" maturity carcasses. Each age group consisted of five or six heifers that had never been bred (virgin), six heifers ovariectomized at 1 yr of age (spayed), and six heifers that had weaned calves approximately 120 d postpartum (single-calf). Slaughter weight was higher (P < .05) for the virgin heifers but total weight gain in the feedlot was similar among the three groups. Single-calf heifers fed 100 d after weaning calves tended to be fatter than virgin or spayed heifers. Carcass maturity scores for the single-calf, virgin, and spayed heifers were different (P < .05); single-calf heifers produced carcasses that appeared older and spayed heifers produced carcasses that appeared younger. Maturity scores coupled with lighter and shorter metacarpal bone weights indicated single-calf heifers matured earlier (P < .05) than the other groups. Panel tenderness and Warner-Bratzler (WB) shear values of rib roasts from virgin, spayed, and single-calf heifers were determined. No differences among groups of heifers existed but scores within each group varied greatly. Marbling score was correlated (P < .05) with panel tenderness and shear force and the hydroxylysylpyridinium (HP) crosslink of muscle collagen was correlated (P < .05) with shear values. Because no significant (P < .05) correlation existed between HP in bone collagen or HP or WB shear values in muscle, we concluded that collagen maturation processes in muscle and bone occur independently. With the exception of differences in bone maturity scores, few meaningful differences in characteristics of virgin, spayed, and single-calf heifers existed, but these maturity differences could change carcass grade and influence value.

Amino Acids↗