88.
Q U A L I T A T I V E C H A R A C T E R I S T I C S O F T H E ElEAT A N I H A L
AS I N F L U E N C E O B Y P H Y S I O L O G I C A L M A T U R I T Y E Q U I V A L E N T S
J.
I.
JI.
GUENTHER
Introduction
Before attempting t o suggest, describe or d i s c u s s any r e l a t i o n ship, d i r e c t cause and e f f e c t or otherwise, between q u a l i t y a t t r i b u t e s of
t h e meat animal and p h y s i o l o g i c a l maturity, we need t o d e f i n e t h e s e terms
or a t l e a s t e s t a b l i s h c r i t e r i a for t h e i r r e s p e c t i v e d e f i n i t i o n and/or
assessment. This w i l l enable us t o coordinate our thinking and keep us i n
t h e same b a l l p a r k , a t l e a s t , during t h e subsequent d i s c u s s i o n which, it i s
hoped, w i l l produce t h e g r e a t e s t u l t i m a t e b e n e f i t from t h i s p r e s e n t a t i o n .
Now, we have a l l been exposed t o t h e terms "Quality" and
"Physiological Maturity". They a r e i n common usage i n our a r e a of a c t i v i t y ,
and we a l l know p r e c i s e l y what i s meant by each term. Or do we?
11. Q u a l i t a t i v e C h a r a c t e r i s t i c s of Meat Animals
L e t ' s begin our d e f i n i t i v e chores w i t h t h e term "Meat Q u a l i t y "
or a s t h e t i t l e suggests, " Q u a l i t a t i v e C h a r a c t e r i s t i c s of t h e Meat Animal",
This t e r m , of course, has various connotations, depending upon
o n e ' s p o s i t i o n i n t h e meat Industry. To c r e a t e some semblance of order,
then, l e t ' s p o i n t out t h e s e various p o s i t i o n s or product q u a l i t y l e v e l s and
suggest what "Quality" e n t a i l s a t each l e v e l ,
F i r s t t h e r e i s t h e Live Animal Level. Which might a l s o be c a l l e d
t h e Producer, Show Ring or Auction Ring l e v e l . What f a c t o r s determine
"Quality" here? When I posed t h i s question t o a f e w of our t o p Live Animal
Judges I got t h e impression t h a t q u a l i t y a t t h e Live animal l e v e l i s a
r a t h e r vague e n t i t y , which i s very h a s t i l y , s u b j e c t i v e l y and i n d i r e c t l y
I'm
assessed, i f a t a l l . Now I ' m not being c r i t i c a l of t h e s e Judges
simply implying t h a t " Q u a l i t y C r i t e r i a " a t t h i s l e v e l a r e extremely
nondescript
-
.
The following i s a synopsis of t h e "Quality" f a c t o r s considered
a t t h e Live Animal Level or i n t h e judging of market animals,
(1)Type
- S i z e f o r weight,
( 2 1 Soundness
legs, etc.
-
s t y l e and eye appeal.
No obvious d e f e c t s , i . e . ,
crooked hind
(3) Expected c a r c a s s merit - involves an estimate o f :
( a ) Expected c u t a b i l i t y or y i e l d of high-priced
c u t s ; muscle t o f a t r e l a t i o n s h i p ; amount of bone, e t c .
( b ) Expected q u a l i t y i n t h e meat, This i s determined
89.
by estimating Carcass Grade, which i n t u r n i s estimated
from t h e f a t content. The f a t content i s determined by
estimating t h e f a t cover over t h e ribs and back (1/2"
1"
maximum). I s animal f a t enough t o grade choice but not
too f a t ?
-
Comments by Judges - "We recognize t h a t a prime c a r c a s s can
have only .3" f a t cover, but t h i s i s t h e exception r a t h e r
It
11
If an animal i s not f a t enough t o grade
than the rule.
choice and appears t o be an e x c e l l e n t y i e l d e r of l e a n c u t s ,
t h e animal may be placed up."
It appears t h a t a t t h e Live Animal Level we a r e guessing c a r c a s s
grade and hoping t h a t t h i s w i l l s u f f i c e a s f a r as e a t i n g q u a l i t y i s concerned. Also, I b e l i e v e it i s obvious t h a t q u a n t i t y i s a major considerat i o n a t t h i s l e v e l and t h a t an assessment of Q u a l i t y i s accomplished only
i n d i r e c t l y and, a t b e s t , i s obscured or confounded w i t h t h e Q u a n t i t y
evaluation. Thus making, i n e f f e c t , q u a n t i t y of l e a n , f a t , and bone a n
i n t e g r a l f a c t o r of q u a l i t y ,
Secondly, t h e r e i s t h e Carcass of Packer Level.
include t h e R e t a i l Level here.
We might a l s o
A s evidenced by t h e f a c t o r s determined i n assigning a f e d e r a l
grade t o a carcass, q u a l i t y a t t h i s l e v e l involves two major considerations.
(1)An estimate of t h e y i e l d of high p r i c e d c u t s and t h e r a t i o of l e a n t o
f a t . This i s done simultaneously when t h e r a t i n g f o r Conformation i s
given. ( 2 ) An e v a l u a t i o n of t h e p o t e n t i a l p a l a t a b i l i t y or e a t i n g q u a l i t y
of t h e carcass. This i s accomplished by s u b j e c t i v e l y a s s e s s i n g and
i n t e g r a t i n g t h e following f a c t o r s : blaturity
a.s evidenced by c e r t a i n
c h a r a c t e r i s t i c s of bone and c a r t i l a g e ; Marbling
a s evidenced by t h e amount
and d i s t r i b u t i o n o f "flecks of f a t " i n t h e exposed longissimus d o r s i , r e c t u s
abdominis, diaphragm, i n t e r c o s t a l and p e c t o r a l muscles, a s w e l l a s i n o t h e r
s t r a t e g i c c a r c a s s l o c a t i o n s , F i n a l l y , t h e color, amount, t e x t u r e s and
firmness of l e a n , u s u a l l y assessed from t h e exposed longissimus d o r s i
muscle, i s considered. It might be pointed out t h a t i f t h e s e l a t t e r f a c t o r s
a r e deemed " s a t i s f a c t o r y " t h e carcass can be quickly graded on t h e b a s i s of
t h e conformation, maturity and marbling r a t i n g s . Curiously enough, t h e s e
f a c t o r s determined from t h e longissimus d o r s i muscle can be o b j e c t i v e l y
evaluated with some degree of p r e c i s i o n . Yet t h e y a r e of seemingly minor
importance. With t h e exception of conformation, t h e aforementioned f a c t o r s
a r e w e l l understood and uniformly assessed. Also, d e f i n i t e l i m i t s a r e
imposed upon t h e s e f a c t o r s . Here again, however, considerable "hoping"
i s practiced.
-
-
Notwithstanding t h e f a c t t h a t " h a 1 Grading" - which supposedly
is
removes t h e Q u a n t i t a t i v e considerations from Q u a l i t y e v a l u a t i o n
a v a i l a b l e and i s used t o a l i m i t e d degree, it seems t o me t h a t , taken a s a
whole, t h e i n d u s t r y i n t i m a t e l y intermingles q u a n t i t y w i t h q u a l i t y a t t h i s
level also.
-
Thirdly and l a s t l y , t h e r e i s t h e Consumer Level, which I l i k e t o
d i v i d e i n t o (1)t h e uncooked or r e t a i l c u t l e v e l a n d m t h e cooked o r meat
entree level.
90.
A t t h e r e t a i l - c u t consumer l e v e l t h e q u a l i t y a t t r i b u t e s i n c l u d e :
r a t i o of l e a n t o ''waste f a t and bone"; c o l o r of l e a n ; marbling; t e x t u r e and
firmness of l e a n ; and odor ( e s p e c i a l l y i f unpackaged). I t h i n k t h a t t h e r e
i s a l s o an assessment made h e r e of t h e water-holding c a p a c i t y of t h e c u t ,
b u t t h i s i s evaluated i n d i r e c t l y a s t h e amount of d r i p or exudate i n t h e
package.
A t t h e cooked cut o r meat e n t r e e l e v e l q u a l i t y i s judged p r i m a r i l y
i n terms of tenderness, j u i c i n e s s , f l a v o r f u l n e s s and aroma. There i s every
reason t o b e l i e v e , however, t h a t t h e consumer a l s o considers t h e c o l o r of
t h e cooked product, t h e water-holding c a p a c i t y (again, t h i s i s i n d i r e c t l y
assessed as, "shrinkage"), and t h e amount of "waste f a t and bone" remaining
on t h e p l a t e .
A s we r e f l e c t on t h e s e meat q u a l i t y a t t r i b u t e s it becomes apparent
t h a t , a t a l l product l e v e l s , t h e q u a n t i t y f a c t o r o r r a t i o of l e a n t o f a t and
bone i s , i n e f f e c t , considered a s an i n t e r g r a l p a r t of meat q u a l i t y , Also,
muscle color and water holding c a p a c i t y appear t o be important across-theboard considerations.
A s meat S c i e n t i s t s , our i m e d i a t e concern l i e s w i t h t h e q u a l i t y
a t t r i b u t e s a t t h e consumer l e v e l s , Yet, we a r e bound and t i e d by t h e
f a c t o r s considered a t t h e l i v e animal and c a r c a s s l e v e l s and consequently we
cannot a f f o r d t o be d i s i n t e r e s t e d i n what i s being c a l l e d "Qpality" a t
these levels.
Our q u a l i t y r e s e a r c h a t t h e consumer l e v e l must be p r o j e c t e d
backwards and t i e d i n more c l o s e l y w i t h measureable a t t r i b u t e s a t t h e s e
upper l e v e l s , i f we a r e going t o make s i g n i f i c a n t progress.
When we consider t h e g r e a t number of f a c t o r s , such a s , breed, sex,
age, s t r e s s , management regime, plane of n u t r i t i o n , s l a u g h t e r procedure,
post-mortem handling and environment, anatomy of t h e c u t , cooking method,
e t c . , which can and do influence t h e q u a l i t y of a meat product, d o e s n ' t it
seem a l i t t l e u n f a i r t h a t t h e consumer's senory mechanism ( a s v a r i a b l e a s
it i s ) only r e a c t s t o t h e product f o r a few f l e e t i n g moments? I f we
couple t h i s w i t h t h e world population vs. a v a i l a b l e farmland problem, t h e
q u e s t i o n a r i s e s , "Would we be b e t t e r o f f i f we concentrated our e f f o r t s on
improving t h e t o t a l q u a n t i t y (of l e a n ) and production e f f i c i e n c y i n our meat
animals, t h e n v i a post-mortem measures influence a s favorably a s we can
product e a t i n g q u a l i t y ? ' ' O r one might a l s o ask, "Is t h e e f f i c i e n t , w e l l
muscled animal a l s o t h e q u a l i t y animal?" Are t h e determining f a c t o r s
mutually r e l a t e d ?
L e t ' s t u r n our a t t e n t i o n now t o p h y s i o l o g i c a l maturity.
111.
Physiological Fmturitx
This term, along w i t h i t s companions p h y s i o l o g i c a l age, chemical
age and maturity i s f r e q u e n t l y encountered i n meat and animal science a r e a s ,
I ' v e o f t e n remarked t h a t i f one i s hard pressed t o e x p l a i n an unusual
experimental r e s u l t , he can always a t t r i b u t e it t o d i f f e r e n c e s i n physiol o g i c a l m a t u r i t y , And i f y o u ' l l scan t h e l i t e r a t u r e , y o u ' l l f i n d t h a t t h i s
t a c t i c i s i n common usage.
91.
I n attempting t o d e f i n e and s e t l i m i t s on Physiological Maturity,
I f i r s t conferred w i t h a number of ''Pure" Physiologists. These f o l k s
claimed t h a t they had never heard o r encountered t h e term used i n t h e i r
area, and while admitting t h a t one could probably e s t a b l i s h c e r t a i n
c r i t e r i a f o r i t s d e f i n i t i o n and measure, t h e y h a s t e l y , b u t graciously,
excused themselves.
Subsequently, I polled a few Animal S c i e n t i s t s . They d i d o f f e r
some suggestions but I got t h e impression t h a t p h y s i o l o g i c a l m a t u r i t y was
X people he
a r a t h e r a b s t r a c t , nondescript e n t i t y and t h a t i f one asked would receive X d i f f e r e n t i d e a s .
-
I n checking w i t h our Medical f r i e n d s , I found t h a t t h e y too a r e
Witness t h e following comments.
"Throughowt 15 years of Conferences on aging sponsored by t h e Macy foundat i o n we never came t o an agreement 2.s t o what i s meant by aging ....r. re a l l
have only a vague idea of what we mean....The g e n e r a l consensus i s t h a t
aging i s t h e progressive l o s s of f u n c t i o n a l capacity of an organism a f t e r
it has reached reproductive puberty....Yet,
some s t e a d f a s t l y maintain t h a t
aging commences with t h e onset of c e l l d i f f e r e n t i a t i o n . I '
i n t h e same dilemma regarding human aging,
Since t h e word physiological r e f e r s t o t h e h e a l t h y functioning of
an organism and maturity denotes t h e s t a t e of being f u l l y developed, a
b a s i c d e f i n i t i o n might be " t h a t occasion i n a n a n i m a l ' s l i f e when a l l
components a r e f u l l y developed and functioning i n a normal, healthy manner.
Thus, p h y s i o l o g i c a l m a t u r i t y i s a f u n c t i o n of age.
Unfortunately, a l l components of t h e animal do not reach t h i s
point simult,aneously, and i n t h i s animal t o animal, organ t o organ v a r i a b i l i t y l i e s t h e d i f f i c u l t y i n a s s e s s i n g physiological maturity. A c a l f might
be considered p h y s i o l o g i c a l l y mature as soon a s it i s capable o f functioni n g as a ruminant, C e r t a i n l y t h e h e a r t must mature during t h e embryonic
s t a t e . Whereas, a muscle might not be considered mature u n t i l it can perform
maximum work.
This gives r i s e t o many questions such a s , what i s normal?
abnormal? What does f u l l y developed mean? I s it t h e p o i n t a t which t h e
s y n t h e s i s of p r o t e i n i s f o r r e p a i r m d maintenance r a t h e r t h a n f o r growth?
Perhaps we can r e c o n c i l e t h e s e d i f f i c u l t i e s , a s a conference, during t h e
d i s c u s s i o n period.
The q u e s t i o n might even a r i s e as t o t h e a d v i s a b i l i t y of expending
considerable research time i n d e f i n i n g and e l u c i d a t i n g p h y s i o l o g i c a l maturity.
I b e l i e v e t h a t t h e obvious r e p l y i s yes - i f we can u l t i m a t e l y c o n t r o l o r
influence it t o our advantage. O f course, t h i s w i l l remain unknown u n t i l
t h e t a s k i s undertaken. If t h e t a s k i s broached and f a i l u r e encountered,
t h e n we've simply had some wonderful academic exercise. E i t h e r way, I l d
say t h e green l i g h t should be on, so l e t ' s proceed.
Where do we s t a r t ? Well, it seems obvious t h a t we cannot b e g i n
t h e quest with t h e i n t a c t animal, p e r se, because it i s t o o complex. Thus,
we need t o subdivide t h e animal, l o g i c a l l y , so t h a t When we a t t a c k t h e
problem with massed i n t e l l e c t u a l a r t i l l e r y , our e f f o r t s w i l l a t l e a s t be
coordinated. I b e l i e v e t h a t a l o g i c a l d i v i s i o n of t h e animal would be on
t h e b a s i s of i t s major t i s s u e s a s follows:
92.
-
-
Epithelial tissue
simple and s t r a t i f i e d
Their f u n c t i o n
i s t o cover t h e body surface, l i n e body c a v i t i e s , and t o
form t h e a c t i v e p a r t s of glands.
-
Connective t i s s u e
General f u n c t i o n i s t o bind o t h e r
t i s s u e s together. They a l s o lend form and s t r e n g t h t o
organs and serve f o r p r o t e c t i o n and leverage. Types of
connective t i s s u e a r e : ( a ) Collagenous - White f i b r o u s ;
( c ) Aerolar - provides
(b) Elastic
o r yellow c . t . ;
cushioning ( i . e . around blood v e s s e l s ) ; ( d ) R e t i c u l a r c . t .
framework of c e r t a i n organs; ( e ) Adipose c . t .
fat;
( f ) Cartilage
hyaline, e l a s t i c , f i b r o c a r t i l a g e ; ( h )
Bone
cancellous ( spongy), compact bone.
-
-
-
-
-
-
Functions i n t h e t r a n s p o r t a t i o n o f
Fluid Tissue
n u t r i e n t s and waste products.
-
Muscular t i s s u e
striated.
Nervous t i s s u e
-
Work, s p e c i a l i z e i n c o n t r a c t i o n
-
smooth,
Conduct nerve impulses.
( A c u t of meat can include a l l of t h e s e ) .
What do we i n v e s t i g a t e about t h e s e t i s s u e s ? Well, we a r e
i n t e r e s t e d i n t h e i r amount, and p h y s i c a l and chemical makeup; haw t h e y a r e
a l t e r e d during growth and development of t h e animal; changes w i t h time;
and t h e i n f l u e n c e of various treatment s t i m u l i , a s w e l l a s breed and sex
d i f f e r e n c e s . I might add t h a t much research has been conducted along
t h e s e l i n e s , b u t not w i t h t h e i n t e n t of i d e n t i f y i n g a p h y s i o l o g i c a l m a t u r i t y
end p o i n t . Also, much of t h i s work i s confounded w i t h many o t h e r v a r i a b l e s ;
consequently s t r a i g h t - l i n e e f f e c t s a r e d i f f i c u l t , i f not impossible, t o
determine.
IV.
Possible Physiological Maturity Indeces
Let us now review some measures which have been suggested or might
be suggested t o a s s e s s p h y s i o l o g i c a l maturity. We a r e i n t e r e s t e d i n t h e
change-rate curves of t h e following e n t i t i e s and would have t o e s t a b l i s h
t h i s f o r each specie.
(1) Hexoseamine: Collagen r a t i o - I n s t u d i e s on t h e growth of
collagen and mucopolysaccharides of t h e femur and s k i n
( r a t s ) during aging, it was observed t h a t t h e r a t e of
d e p o s i t i o n of collagen exceeded t h a t of t h e mucopolysaccharides (determined a s hexoseamine).
(2)
S u s c e p t i b i l i t y of E l a s t i n f i b e r s t o enzyme o r chemical
During maturation collagen f i b e r s degrade
Hydrolysis
t o form a m a t e r i a l d e f i c i e n t i n Hydroxproline, which
gives r i s e t o e l a s t i n f i b e r s which a r e s u s c e p t i b l e t o
enzyme hydrolysis.
-
93.
Ketosteriod: Corticoid r a t i o - Adrenal c o r t i c o i d s have an
a n t i - a n a b o l i c a c t i o n . Androgens of t h e a d r e n a l and t e s t i c u l a r organs a r e anabolic. Urinary androgens diminish w i t h
age, while t h e e x c r e t i o n of c o r t i c o i d s i s l e s s a f f e c t e d
by age.
Changes i n a c t i v i t y of Respiratory enzymes,
cytochrome and s u c c i n i c oxidases.
Especially
Changes i n i n s o l u b l e and soluble p r o t e i n s . These change
with aging, b u t t h e e x t r a c t i o n conditions must be r i g i d l y
specified.
Water: p r o t e i n r a t i o . Water content of muscle decreases
w i t h age while t h e p r o t e i n content increases.
Albumin:
globulin r a t i o .
Increases with age.
Changes i n p r o t e i n content of blood. There i s a r a p i d
i n i t i a l i n c r e a s e followed by a period of slow change.
Changes i n dimensions of various anatomical u n i t s , i . e .
sarcomere, f a s c i c u l a , e t c .
Closing of epiphyseal p l a t e s . This c o n t r o l s t h e amount
of long bone growth and i s a f f e c t e d by female hormones.
Other bone c h a r a c t e r i s t i c s , i.e.,
composition e t c .
hardness, chemical
Weight of eyeballs. This has been used i n s t u d i e s on t h e
maturation of w i l d animals,
P r o t e i n c h a r a c t e r i s t i c s of t h e I r i s .
v i a electrophoresis.
Could be determined
Nuclear number. A n end p o i n t of physiological m a t u r i t y
might be determined when t h e parameters of nuclear number
( a s D.N.A.)
show no s i g n i f i c a n t increase.
No doubt, each of you could add t o t h i s l i s t . Whether any or a l l
of t h e s e measures would prove t o be v a l i d from o u r viewpoint i s B matter of
conjecture. Perhaps, a s a conference, we could resolve t h i s . It seems t o
me t h a t t h e f i r s t t h i n g we should do i s t o e s t a b l i s h c e r t a i n c r i t e r i a f o r
an index of p h y s i o l o g i c a l maturity.
V.
C r i t e r i a for an index of Physiological Maturity
I n order for a phenomenon t o serve a s a measure of p h y s i o l o g i c a l
m a t u r i t y it should possess t h e following c h a r a c t e r i s t i c s .
(1) We must be a b l e t o measure it w i t h a high degree of
p r e c i s i o n . It would be d e s i r a b l e i f we could determine
t h e e n t i t y on t h e l i v e animal.
94.
It must change w i t h m a t u r i t y ( t i m e ) and be d i r e c t l y
a s s o c i a t e d w i t h t h e maturing process (cause and e f f e c t
relationship).
The change ( i n 2 ) must be i r r e v e r s i b l e o r proceed i n only
one d i r e c t i o n under normal circumstances.
The change must occur w i t h i n c e r t a i n time l i m i t s (8-24
months f o r c a t t l e , s h o r t e r span f o r sheep and hogs).
This could be a major problem.
It must be r e p r e s e n t a t i v e of t h e whole r a t h e r t h a n a
p e c u l i a r i t y of a p a r t .
VI.
Q u a l i t a t i v e C h a r a c t e r i s t i c s and Animal Maturity.
Now t h a t we have reviewed some a s p e c t s of t h e terms Q u a l i t y and
Physiological Maturity, I ' d l i k e t o spend t h e s e l a s t few minutes, i n
summarizing some of t h e r e s e a r c h on t h e influence of m a t u r i t y ( i n most
cases age)on meat q u a l i t y . I have omitted t h e a d j e c t i v e Physiological
here because I do not b e l i e v e t h a t t h i s e n t i t y has been p r e c i s e l y
i d e n t i f i e d i n t h e works I have studied. However, I do t h i n k t h a t it has
been c l o s e l y approximated i n t h e r e s e a r c n u t i l i z i n g bone c h a r a c t e r i s t i c s
a s t h e c r i t e r i a f o r maturity.
1. Ratio of l e a n t o f a t - Since we've s a i d t h a t q u a l i t y
includes q u a n t i t y , l e t ' s begin here. This r a t i o changes w i t h i n c r e a s e s
i n body weight and age. It becomes smaller and l e s s d e s i r a b l e a f t e r a
c e r t a i n point i n t h e animal's development o r maturation. Our d a t a show
t h i s t o be a t ea. 75# of body weight o r 10-11months of age, or when
about 87% of t h e l e a n p o t e n t i a l i s deposited. Level of n u t r i t i o n simply
a l t e r s t h e r a t e of change (1-3 months
depending on r a t i o n ) . T o t a l
change w i l l be very s i m i l a r .
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-
2.
Color of l e a n
The appearance of t h e cut meat surface
depends upon t h e q u a n t i t y , and chemical and p h y s i c a l s t a t e of i t s p r o t e i n aceious pigment myoglobin. Color i s o f t e n expressed a s Hue, Chroma, and
and
Value, and may be influenced by a v a r i e t y of f a c t o r s , both a n t e
post-mortem.
(Specie, breed, sex, age, anatomical l o c a t i o n of c u t ,
e x e r c i s e , n u t r i t i o n a l l e v e l , marbling, e t c . ) The ante-mortem f a c t o r s
c o n t r o l t h e amount of pigment, while t h e post-mortem f a c t o r s determine
i t s chemical or p h y s i c a l s t a t e .
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I n general, beef becomes darker a s m a t u r i t y advances, The redness of Hue i n c r e a s e s w i t h age b u t t h e Value o r b r i g h t n e s s tends t o
decrease. I n many s t u d i e s t h e intra-muscular f a t content has had a profound influence on c o l o r r e s u l t s .
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3. Marbling
When we consider n u t r i e n t demand during growth and
development, t h a t i s 1st f o r bone, 2nd f o r muscle, 3rd f o r f a t , it would
seem t h a t d e p o s i t i o n of intra-muscular f a t s would d e f i n i t e l y be r e l a t e d t o
animal maturity. The a c t u a l influence of marbling, per se, on meat
p a l a t a b i l i t y i s t h e s u b j e c t of much debate. I do not f e e l t h a t t h e i n fluence of marbling, a s a s e p a r a t e e n t i t y , has ever been adequately
elucidated.
4. Water holding capacity - Since it a f f e c t s t h e appearance o f
t h e meat before cooking, i t s behavior during cooking, and i t s j u i c i n e s s
a f t e r cooking, t h e WHC of meat i s very important. Many f a c t o r s , such as,
specie, age, muscle function, P.K g l y c o l y s i s and u l t i m a t e pH have been
shown t o a f f e c t W C . I n g e n e r a l IdHC diminishes a s t h e animal matures.
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5. J u i c i n e s s
There has been much d i f f e r e n c e of opinion concerning t h i s q u a l i t y a t t r i b u t e and i t s influence by age o r maturity.
Some workers r e p o r t a.n i n c r e a s e i n j u i c i n e s s w i t h maturity o r age, while
o t h e r s r e p o r t opposite r e s u l t s . I b e l i e v e t h a t t h i s c o n f l i c t i s due t o
t h e f a c t t h a t j u i c i n e s s i s influenced not only by t o t a l moisture b u t a l s o
by f a t , aroma, f l a v o r . Thus while a young animal may have more t o t a l
moi st ure it d o e s n ' t have t h e f a t and consequently aroma t o s t i m u l a t e t h e
s a l i v a r y glands for a sustained " j u i c y sensation".
definite
due t o a
increase
however,
de t r a c t s
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6. Flavor and aroma
Apparently animal age o r m a t u r i t y has a
enhancing e f f e c t on f l a v o r and aroma. This, however, could be
l a r g e e x t e n t on t h e increased f a t content of o l d e r animals. The
i n f l a v o r w i t h advanced m a t u r i t y i s not a s t r a i g h t l i n e d event,
and t h e r e i s a p o i n t (18-24 mos.) beyond which age a c t u a l l y
from f l a v o r .
7. Tenderness - Perhaps more e f f o r t has been expended i n t h e
study of t h i s e l u s i v e c h a r a c t e r i s t i ? than any o t h e r q u a l i t y a t t r i b u t e .
Tenderness i s influenced by a l l o t h e r q u a l i t y a t t r i b u t e s , e i t h e r d i r e c t l y
o r i n d i r e c t l y , a s well as by t h e s t a t e o r a r c h i t e c t u r e of many anatomical
t i s s u e s . I n g e n e r a l tenderness decreases with age o r maturity, b u t , t h i s
decrease i s by no means s t r a i g h t l i n e d .
The c o n f l i c t i n g r e s u l t s which appear i n t h e l i t e r a t u r e on
q u a l i t y research a r e t o be expected, For, many of t h e q u a l i t y a t t r i b u t e s
of meat, as w e l l as t h e f a c t o r s influencing them, have never been p r e c i s e l y
determined. The x a j o r d i f f i c u l t y stems from t h e f a c t t h a t no one a t t r i b u t e
has ever been assessed independently of another. Perhaps t h i s i s impossible.
Thus s t a t i s t i c a l methods must be u t i l i z e d t o remove t h e influence o f a '1cov a r i a b l e ; " and i n so doing we introduce another problem. We cannot a s s e s s
each v a r i a b l e w i t h t h e same degree of p r e c i s i o n o r accuracy. Thus, t h e
mathematical c o r r e c t i o n may be i n v a l i d , from a b i o l o g i c a l standpoint.
The problem b o i l s down t o t h e fa.ct t h a t we simply do not know
enough about t h e behavior o f t h e animal during growth and development.
Also, our methodology
Physical, Chemical, and S t a t i s t i c a l
needs t o be
coordinated. To me, t h e coordination of r e s e a r c h e f f o r t should be one of
t h e major f u n c t i o n s of our a s s o c i a t i o n .
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One of t h e t h i n g s t h a t has s e r i o u s l y hampered Q u a l i t y research has
been t h e f a c t t h a t it has been a by-product of n u t r i t i o n and g e n e t i c experiments. This has caused much confounding of t h e v a r i a b l e s which a r e of
i n t e r e s t t o t h e meat s c i e n t i s t . If we a r e r e a l l y going t o answer our quest i o n s on q u a l i t y and p h y s i o l o g i c a l maturity, we must work from t h e ground up.
We need t o s e t a s i d e a breeding herd and produce and manage t h e animals so
t h a t we have t h e b a s i c experimental u n i t s necessary t o study animal behavior
during growth and development and t o adequately a s s e s s and r e l a t e animal
q u a l i t y a t t r i b u t e s and p h y s i o l o g i c a l maturity.
96
.
DR. ZINN: To l e a d t h e d i s c u s s i o n t h i s afternoon, I have
D r . J. L. McBee, West Virginia University, t o be your d i s c u s s i o n
asked,
l e a d e r . I ' m s u r e he w i l l f i e l d t h e questions t o t h e r i g h t person t o
answer them a t t h i s time. Jim.
DR. McBEE: Harold has presented a review paper covering a wide
range of work which has been done on meat animal growth and composit i o n , p o i n t i n g out t h e way we have been going i n t h i s type of work.
J i m has covered q u a l i t a t i v e r e l a t i o n s h i p s of meat animals as
influenced by p h y s i o l o g i c a l maturity, and during h i s p r e s e n t a t i o n
has r a i s e d a number of i n t e r e s t i n g questions. These two speakers
pointed out t o me before t h e y began t h e s e s s i o n t h a t t h i s was t o
be a period of r e c i p r o c a t i o n not of i n t e r r o g a t i o n . However, we
would l i k e t o r e c e i v e opinions of anybody, questions t h a t anybody
i n t h e audience has and t o r e a l l y r a i s e some d i s c u s s i o n during t h e
a l l o t t e d time. 'who has t h e f i r s t question o r comment?
DR. HUFFMAN: There was a question r a i s e d a t t h e r e c e n t
conference a t t h e University of Missouri t h a t has bothered me and
I ' v e discussed it w i t h s e v e r a l o t h e r s . I wonder i f you would speak
on it very b r i e f l y . You may remember t h e discussion. It centered
around t h e problem, i s body water i n a normal "physiologically
mature" animal a constant?
DR. GUENTHER: I'll answer you t h i s way. The d i s t i n g u i s h e d
group t h a t attended t h a t conference d i d n ' t come t o a d e c i s i o n on
t h i s , and I d o n ' t t h i n k I can. Laugh.
DR. McBEE: I t h i n k t h a t answers your question.
t h e next question? Anybody have any comments t o make?
Who has
MR. SULZEACHER: I h a t e t o see t h e afternoon g e t t i n g so
d u l l so, I ' m going t o ask a f o o l i s h question. Why a r e we i n t e r e s t e d
i n measuring p h y s i o l o g i c a l maturity? (Laugh).
DR. GUENTHER: Foolish questions deserve a f o o l i s h answer.
Like t h e o l d Prof. a t Oklahoma S t a t e d i d one time when he asked an
i n d i v i d u a l how he placed a c l a s s of hogs. Kid says, "Well, Prof.,
what do you t h i n k about it?" Prof. says, "I d o n ' t t h i n k , I knowlll
Kid says, "I d o n ' t t h i n k I know e i t h e r . " (Laugh), I b e l i e v e i f you
r e f l e c t upon t h a t which i s s a i d i n j e s t , t h e r e may be a l o t o f t r u t h
i n it. But a s I t r i e d t o p o i n t out i n my p a r t of t h e p r e s e n t a t i o n ,
B i l l , we won't know whether i t ' s worthwhile u n t i l we can a s s e s s it
and run some r e l a t i o n s h i p s . I b e l i e v e t h a t ' s t h e way w e ' l l have t o
l e a v e it.
DR. McBEE: Who e l s e has something t o comment on? If t h e r e
a r e n ' t a l o t of questions or comments a t t h i s time, we w i l l t u r n t h e
program back over t o President J. W. Cole. (Applause).
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