Koohmaraie of the USDA comments on Piedmontese-myostatin
affects on tenderness:
Quoted from this research
"Heritabilities and Phenotypic and Genetic
Correlations for Bovine Postrigor Calpastatin Activity,
Intramuscular Fat Content, Warner- Bratzler Shear
Force, Retail Product Yield, and Growth Rate"
D. Shackelfordts, M.
Koohmaraie, L. V. Cundiff,
K. E. Gregory*, G. A.
Rohrer", and J.
W. Savell *Roman L. Hruska
U.S. Meat Animal Research
Center, ARS, USDA, Clay
crosses had the lowest WBS (Warner Bratzler Shear
Force*) despite having the second-lowest amount
of IMF. Additionally, Piedmontese crosses had
the fourth most calpastatin activity. Thus, these
data suggest that the extreme tenderness of
muscle-hypertrophied [Piedmontese] cannot be
explained by variation in CA [Calpastatin] or
Further studies to elucidate the mechanism responsible
for the extreme tenderness of muscle-hypertrophied
[Piedmontese] cattle must be conducted."
lower the WBS, the more tender the meat.
this study, Piedmontese ranked as most tender,
followed by Pinzgauer, then Hereford, out of
11 breeds compared in the USDA-MARC GermPlasm
Evaluations. Further – Piedmontese crosses
had the highest retail product percent, and the
second lowest IMF in this comparison.
the full report HERE (opens
as a large PDF file - download will be slow on
note on Calpastatin
a calcium-dependent protease, has been
recognized as a key player in postmortem
tenderization of skeletal muscle (Koohmaraie,
1996). Calpastatin is a widely distributed
endogenous inhibitor protein that specifically
acts on calpain. The calpain system, and its inhibitor, calpastatin, is believed to
be the primary proteolytic enzyme system
involved in postmortem tenderization of
aged beef (Koohmaraie et al., 1991). Koohmaraie
(1996) indicated that the degradation of
structural muscle proteins by calpain is
responsible for meat tenderization during
postmortem storage of meat. Calpastatin
activity at 24 h postmortem is inversely
proportional to postmortem tenderization
and accounts for a greater proportion of
the variation in beef tenderness than any
other single variable (Koohmaraie, 1994).