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Beef Cattle Paper
Gene Star Has Taken A Large Leap In The Beef Industry.
Introduction
Today’s beef market demands a consistent
product. The consumer demands a product that is juicy, tender, and highly
palatable. It is the producer’s job to produce beef products to be passed
to the packer for processing. The packer must then process the beef
carcass in a way that will be appealing to the consumer. All in all the
process of delivering beef to the consumer is catered to the consumer.
In 1991 the National Beef Quality
Audit showed that consumers rated palatability problems sixth and
toughness seventh and in 1995 tenderness problems ranked second and
palatability third (Bowser). If the product is tough, dry, or low in
palatability the consumer will turn to other meat sources. To keep the
consumer’s attention the beef industry must identify its problems or
concerns and immediately take action.
One of the beef industry’s current concerns is with Bos
Indicus breeds. These breeds are known for producing tougher, less
palatable meat. Bos Indicus breeds are known for carrying a specific
protein called Calpastatin which inhibits the calcium dependent neutral
proteases that play a regular role in muscle proteolysis and post-mortem
meat tenderization (Nonneman et al., 1999). Many tests have been
administered and many trials have been conducted to try to reduce the
calpastatin in post mortem meat. Dr. Jeff Savell said it simply “The more
calpastatin you have, the less opportunity you have for these calpains to
break the muscle down during aging and the more opportunity we have for
some tough meat (Bowser).”
Literature Review
The quality of a beef carcass is determined by several
measurements. Tenderness is measured by the Warner-Bratzler shear force
(WBS) test, the amount of marbling is measured and sensory evaluation is
done which include tenderness juiciness and flavor. A study conducted by
B.W. Woodward, S.K. DeNise, and J.A. Marchello (2000) showed that
calpastatin activity measured 24 hours postmortem in bovine longissimus
muscle (tenderloin) is correlated with Warner-Bratzler shear force (WBS)
measurements (2000). This team chose to prove that there was a correlation
between live animal measurements of calpastatin and those measurements
taken 24 hours post mortem. Biopsies were taken 2 days before slaughter
from the supraspinatus muscle on the anterior surface of the scapula. A
rib section anterior to the 12th and 13th rib
interface was collected from all animals tested 22 to 23 hours postmortem,
sensory panel was conducted, and WBS measurements were taken. Correlations
were found in the WBS measurements and the sensory panel results. Similar
calpastatin activity values are possible with ante- and postmortem tissue
samples, suggesting the possibility of using measurements from live tissue
biopsies from other than the longissimus muscle to predict end product
tenderness (Woodward et al., 2000).
Several studies have been done comparing Angus (Bos
Tarus) and Brahman (Bos Indicus) breeds on their tenderness.
One such study conducted by O’Conner et al. (1997) compared cattle
that were 3/8 Bos Indicus to those of Bos Tarus cattle and showed that
they had similar marbling scores but the Bos Indicus influenced cattle had
higher 24 hour calpastatin activities. A similar study was done by Pringle
et al. (1997). The researchers determined calpains and calpastatin
activities from fresh longissimus muscle samples using anion-exchange
chromatography. This study concluded that calpastatin activity increased
linearly with increasing percentage of Brahman breeding. The research also
showed a strong linear relationship between calpastatin activity and
marbling score. The higher the calpastatin activity the lower the marbling
score would then be for those cattle influenced by Brahman breeding
(Pringle et al., 1997).
Supplementation of Vitamin D has been suggested by many
as an answer to the tenderness problem brought on by some breeds of
cattle. This was the objective of an experiment done by Montgomery et al.
(2002). This team set out to determine the effect on doses of vitamin D on
feedlot performance and improvement of Warner-Bratzler shear force (WBS)
and panel tenderness. In this study a total of 67 steers were fed one of
six levels of Vitamin D. Results showed that calpastatin and calpain
activity were not influenced by treatment but muscle was increased.
Feeding Vitamin D did not increase carcass quality or yield traits,
however, the WBS measurement decreased and the sensory panel tenderness
was increased. Thus, feeding Vitamin D to steers will effectively improve
tenderness when cattle tend to be tough and have no impact on cattle that
produce tender beef already.
Another such study measured the likelihood of feeding
Vitamin D to cattle to improve tenderness in the finished product. Karges
et al. (2001) also fed steers varying amounts of Vitamin D over a pre
slaughter period of time. Carcass traits were compared, WBS measurements
were taken, calpastatin activity and water holding capacity were measured
and sensory characteristics of the muscles were conducted. The results
suggest that supplementing vitamin D in proper amounts will improve beef
tenderness though increasing blood plasma Calcium concentrations and water
holding capacity (Karges et al., 2001).
Improving the tenderness factor was the main focus of a
study conducted by Riley et at. (2003). This study evaluated the
likelihood of improving tenderness pre slaughter. Heritabilities for
calpastatin activity were very low and results indicated that improvement
in tenderness based on selection for favorable shear force sensory panel
tenderness or calpastatin activity would be slow and would therefore be
better intervened post slaughter (Riley et al., 2003).
However a company by the name of GeneSTAR is trying to
improve pre-slaughter selection. Currently GeneSTAR is doing the most
research and work continually on calpastatin activity and how to control
it pre-slaughter. Providing beef consumers with a guaranteed tender and
satisfying product took a large leap with the introduction of GeneSTAR
tenderness. This test detects two different form of the gene calpastatin,
one associated with increased tenderness and one associate with increased
toughness. Research has shown that pre-harvest tenderness selection tool
indicates that testing and selecting for differences in calpastatin gene
reduce the number of tough eating steaks by at least half. Their studies
also showed that Brahman breeds were more likely to be considered tough
and detected by the GeneSTAR tenderness tests. GeneSTAR Tenderness is a
powerful tool for seed stock and commercial producers concerned about
enhancing beef eating quality (Nonnenman et al., 1999).
Conclusions
Calpastatin is an enzyme that is naturally occurring in
a carcass. Calpastatin inhibits normal meat tenderization during post
harvest aging (Nonneman 1999). If calpastatin can be controlled in the
carcass, the carcass will become tenderer. However, calpastatin is a major
problem in today’s beef industry. Consumers demand a pleasurable product.
Many producers are trying to solve this problem and they have the
assistance of many researchers. Producers are turning to more Bos Taurus
breeds (Angus, Hereford, etc.) and avoiding Bos Indicus (Brahman,
Beefmaster, ect.) influenced cattle and have even tried to feed Vitamin D
supplements to improve the tenderness of beef. GeneSTAR has gone as far as
doing research and conducting experiments on cattle known for toughness
and developing indication tests to try and prevent tough cattle reaching
the consumer. GeneSTAR has take a large leap in the beef industry for the
better of the consumer. Due to their current experiments and test,
GeneSTAR has reduced the number of tough steaks presented to the consumer
by at least half (Nonneman 1999). With current steps being taken and
continuing research beef tenderness will no longer be a problem for the
consumer. The progress being made is phenomenal and we should continue to
look for improvement in beef for years to come.
References
Riley, D.G.,
C.C. Chase Jr., A.C. Hammond, R.L. West, D.D. Johnson, T.A. Olson, S.W.
Coleman. 2003. Estimated genetic parameters for palatability traits of
steaks from Brahman cattle. J. Anim. Sci. 81:54(7).
Montgomery,
J.L., M.A. Carr, C.R. Kerth, G.G. Hilton, B.P. Price, M.L. Galyean, R.L.
Horst, M.F. Miller. 2002. Effect of vitamin [D.sub.3] supplementation
level on the postmortem tenderization of beef from steers. J. Anim. Sci.
80:971(9).
Karges, K., J.C. Brooks, D.R. Gill, J.E. Breaszile, F.N.
Owens, J.B. Morgan. 2001. Effects of supplemental vitamin [D.sub.3] on
feed intake, carcass characteristics, tenderness, and muscle properties of
beef steers. J. Anim. Sci. 79:2844(7).
Woodward, B.W., S.K. DeNise, J.A. Marchello. 2000.
Evaluation of calpastatin activity measures in ante- and postmortem muscle
from half-sib bull and steers. J. Anim. Sci. 78:804(6).
Pringle, T.D., S.E. Williams, B.S. Lamb, D.D. Johnson,
R.L. West. 1997. Carcass characteristics, the calpain proteinase system,
and aged tenderness of Angus and Brahman crossbred steers. J. Anim. Sci.
75:2955(7).
O’Connor, S.F., J.D. Tatum, D.M. Wulf, R.D. Green, G.C.
Smith. 1997. Genetic effects on beef tenderness in Bos indicus composite
and Bos taurus cattle. J. Anim. Sci. 75:1822(9).
Nonneman, D., S. Kappes, M. Koohmaraie. 1999. Rapid
Communication: a Polymorphic Microsatellite in the Promoter Region of the
Bovine Calpastatin Gene. J. Anim. Sci.
Bowser, D. Tenderness Proves Tough Nut For Beef Industry to Crack.
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