Chemical and Histological Characteristics of the M. Longissimus in Young Bulls Selected for Tenderness or Leanness

Abstract

Certain chemical and histological characteristics of the longissimus of seven yearling bulls selected for tenderness and seven yearling bulls selected for leanness were compared. Selection for tenderness in contrast to selection for percent trimmed round and loin since 1959 has not produced significant differences between the two groups for sarcomere length, fiber area, ultimate muscle pH, collagen content, labile collagen yield or proportion of α and β collagen sub-units in muscle. In addition, factors in epimysial tissue which have been associated with cross-linking of the collagen molecule were not affected. Muscle pH at 1 hr. postmortem was significantly lower in carcasses from the tender line of cattle when compared to those from the lean line. Both muscle pH and temperature at 1 hr. postmortem were closely associated with tenderness. Copyright © 1970. American Society of Animal Science . Copyright 1970 by American Society of Animal Science