SF 229
M85
Copy 1

The Estimation
of Condition in Cattle.

BY

J. ALAN MURRAY, B.Sc.

Lecturer wn Agricultural Chemistry at University

College, Reading.

READING :
CHARLES Exssury, 25, Mint LANg.

1914.

PRE ACE:

The following paper was read at the Meeting of the British
Association in Australia this year, but owing to the outbreak of
war and other causes it has not been reported in the papers.
This is the more regretable because the paper was not designed
to settle the question, but to open it—to invite criticism and
co-operation. The author has, therefore, deemed it advisable to
reprint it 7 extenso with this object in view. He will welcome
any public or private criticism either of the general proposition
or of details, such as the best method of making the measure-
ments, expressing results, etc.; and he will be extremely glad to
receive or to have his attention called to any data bearing on
the subject.

Jneaer vie

READING,
24th October, 1914.

By trausfe)
APR 29 1919

Che Estimation of Condition in Cattle,

BY
J. ALAN MURRAY, B:Sc.,

Lecturer in Agricultural Chemistry at University College,

Reading.

HE verbal terms used by farmers to describe the “condition”
of animals, e.g., “fat,” ‘“ half-fat,” « store,’’ etc., are vague
and indefinite. They are, however, in common use, and

it would be futile to suggest that they should be changed or
abandoned; but it is not, perhaps, inopportune to enquire
whether a more definite signification might be ascribed to them.
In order to ascertain what these terms connote in the ordinary
language of those who use them, it is convenient first to con-
sider the noun (condition) before attempting to deal with the
adjectives.

The condition of cattle is usually judged by the appearance
of the animals, the flexibility of the skin and so on: but these
indications are not entirely satisfactory. The vagueness of the
terms used to describe condition is, no doubt, due in large
measure to the difficulty of judging it. The only exact method
of expressing all the various degrees of condition is by means of
numerical values, and if these are to be employed, the condition
must be determined in a different manner.

The live weights are expressed by numbers. These vary with
the condition of the animals, but they cannot be used as a
general test of condition because they also vary with the size
(extension of the frame). Thus, if two animals were in the
same condition but one of them was bigger than the other it
would weigh heavier. If two animals were of the same size
but one of them was in better condition than the other it
would weigh heavier. But if two animals were of the same
size and in the same condition they would have the same
weight.

4

It appears, therefore, that the term condition, as used in this
connection, may be interpreted to mean that quality which is
measured by the ratio of live weight to size. This view is more
concisely expressed by the equation

where M is the live weight, S is the size, and C is a number
which expresses the condition of the animal.

This proposition is not entirely novel, but, so far as the author
is aware, it has not previously been expressed in exactly this
form. It is well known that the weight of dressed carcass can
be estimated, with more or less accuracy, from the size as
determined by measurement of certain dimensions, viz., the
length and girth of the animal. Several rules are given by
which the result may be worked out. Most of them, however,
apparently aim at simplicity rather than accuracy. Only one
of them attempts to take into account the condition of the
animal. This rule is generally rendered as follows: “the girth
squared multiplied by the length (both in feet) and the product
multiplied by a factor (:23, :24, -25, or -27) according as the
animal is moderately fat, fat, prime fat, or very fat, gives the
weight of dressed carcass in imperial stones.” If the factor
which varies with the condition of the animal be designated by
the symbol C and the length, girth and live weight by L, G and
M respectively, the rule may be expressed in the form of an
equation as follows:

M = Cx ly x5Ge

It is generally considered that this rule, though better than
any of the others, is not altogether trustworthy. This is
attributable partly to the difficulty of making exact measure-
ments and partly to the fact that the rule itself is radically
unsound. Thus, if the factor C be evaluated in terms of the
others by the usual methods we obtain

M
C=

LG?

Stated in this form it will be seen that the equation involves
a contradiction in terms. When an animal becomes fat the
girth increases to a certain extent (and C should become greater) ;
but since G occurs in the denominator, any increase in the
value of G tends to diminish that of C; and since G is squared,
the error thus introduced may be considerable.

~

9)

The object of the foregoing discussion was not primarily to
criticise this particular rule, but to show that the proposition
C = M/S is an accepted idea. Incidentally it appears that S
may be rendered by L x G (or some function of the same)
provided that G represents the girth in store condition; in the
case of fat beasts some allowance must be made for the increase
of girth due to fattening. The equation may, therefore, be
written provisionally as follows:

In order to test the matter, and if possible to determine X,
observations of the length, girth and live weight were made upon
a number of animals, and these data, together with certain
others derived from them, are given in the table below.

TABLE: TT:

STORE CATTLE.

Mavic: anes | Length. Girth. i - | 7 Pee
a | © (G) L Ei | G aa
pounds. | inches. | inches. ve | a
371 882 52 72 1385 | 16°96 | 12°25 4:71
370 | 924 | 52 72k | 1:394 | 17-77 | 12°74 | 5-08
359 952 48 71 1-479 | 19°83 | 13-41 6:42
365 | 952 | 46 70% | 1:533 | 20-69 | 13°53 7-16
MopERATELY Fat Breasts.
318 1148 48 17 | 1:604 | 23-91 | 14-91 9:00
302 1232 54 | 78 1-444 | 22-81 | 15°80 7-01
305 1400 by, 1) 382 1-439 | 24:56 | 17-07 7:49
185 1428 58 | 81 1:396 | 24-62 | 17-63 6-99

The data are arranged in the order of the live weights, and as
it happens that this is practically the same as the order of
fatness when ultimately worked out it might be inferred that
the live weight is, by itself, a reliable index of condition. It is
true that when animals are fully grown any change in their

6

weight (+ or —) indicates a change of condition and is an exact
measure of the same, because the size remains constant. This,
however, does not apply to growing animals, nor does it enable
us to compare one with another. It will be seen, on reference
to the table, that Nos. 359 and 365 have exactly the same weight,
but the latter is 2in. shorter and 4in. less in girth, 2.e., it is
altogether a smaller animal and could not, therefore, have the
same weight unless it were in better condition,

It may be assumed that in any given animal the ratio of girth
to length is a constant quantity, 2.e., that it is not affected by
growth as apart from fattening, and that the length 1s indepen-
dent of condition. If this be so, the size of the animal may be
gauged by the latter dimension alone, and any change in
condition (+ or —) will be determined by the variation in the
ratio M/L. It should be possible, therefore, in this way, to
compare the condition of the animal at all stages of growth, but
not necessarily to compare one animal with another.

When two or more animals are to be compared it cannot be
assumed that the ratio of girth to length is the same in all.
The few examples given in the table show that it is not, and the
ratio M/L cannot, therefore, be regarded as a reliable index of
condition for the purpose of comparison. Thus, if two animals
were of the same length, but of unequal girth, that which had
the greater girth would weigh heavier and would show a higher
ratio of live weight to length, though there was no difference in
condition. The variation in the ratio G/L is, however, less than
might be supposed. In the case of the store animals it ranged
from 1:385 to 1:533, and in the case of the fat beasts from 1:°396
to 1:604. The ratio M/L does, therefore, reflect the condition,
and may even be regarded as a fairly approximate estimate of it.

Referring again to the table, it will be seen that the ratio
M/G is always less than M/L, because, of course, G is always
greater than L, but it varies in much the same manner. The
order of fatness judged by either of these two ratios is the same.
At first sight it appears as if the condition were reflected with
equal accuracy by either, but as G is not independent of condi-
tion it is clear that such is not the case. It will also be noticed
that though the ratio M/G varies in much the same manner as
M/L, it does not vary in the same degree. The difference
between them is greater in the case of fat beasts than in stores.
This is probably attributable to the increase in girth which takes
place when the condition of the animal improves. Any increase
in the value of G diminishes the ratio M/G and so tends to
increase the difference between M/L and M/G.

An attempt to estimate the increase in girth in this way
showed that when the animals are moderately fat it is about

7

four per cent.; but when the method was applied to similar
data from other sources it was found to be unsatisfactory.

Upon consideration, it seems clear that the increase must be
some fractional part or percentage of the girth observed, 7.e., it
must be 1G/100. Now the ratio M/L varies with the degree of
fatness, and, though not itself a reliable test of condition, it
should afford a fairly close approximation to the value of I.
Thus, when the animal is in store condition, 7.e., when there is
no increase due to fattening, M/L = 17, and since, in that case,
Tis 0, 1 = (M/L — 17). Again, when the animal is moderately
fat, M/L = 25, and since, in that case, the value of I is about 4,
1.e., about half the difference between 25 and 17, I = 0°95
(M/L — 17). The expression G/200 (M/L — 17), theretore
represents the increase in girth due to fattening, and the original
girth—which the animal would have had had it remained in
store condition—may be found by subtracting that amount from
the girth observed. In short, the expression G/200 (M/L — 17)
represents the value of X in the provisional formula (page 5).

If the value of C be now worked out in each case it will be
found that owing to the accident of the particular units em-
ployed (pounds and inches) the results are fractional numbers.
For purposes of comparison it is more convenient to take the
condition of the leanest animal-—assumed to be a typical store—
as 100, and that of the others pro rata. The factor required for
this purpose is 424-4. The revised formula may now be written
as follows:

494°4 M
(tees ae anes epee ee
| G |
ee == — = (Ni = ine
| 200

The original girth and present condition of each of the animals
calculated by this formula is shown in the table below.

TasuE II.
STORES. Fat BEASTs.
No. git) OHI conattion, | Now | (Stthg| Eine! conation
871 72 72 1000 || 302 | 77 75-7 197-4
370. | 72:5 | 72:3 104:5 || 318 78 74°3 136°5
359 | 71 70 1202 || 305 | 82 | 789 | 1821
365 | 70:5 | 69:2 | 1292 | i85-| 81 | 77:9 | 1844
| }]

8

It is noticeable that according to these results, Nos. 359 and
365, though classed as stores, are in nearly as good condition as
those classed as fat, and there seems to be no reason to doubt
the truth of this inference. The policy of maintaining an animal
in the condition of No. 865 at that stage of growth cannot be
discussed here; but it may be said in passing that one of the
arguments by which it is sometimes supported—the more rapid
increase in the live weight of young animals—-seems to be
beside the question. The additional weight which a young
animal puts on is mainly, if not entirely, due to growth. There
is nothing to show that a young animal puts on true fattening
increase more rapidly or more easily than one which is fully
grown. In the absence of some means of estimating condition
—gsuch as that now proposed—the question is a difficult one to
investigate.

From a purely practical standpoint the condition of animals
is of interest chiefly in regard to its bearing on the question of
valuation. When animals are sold by weight, the rate by which
the price is determined is fixed at so much per cwt., according
to the condition of the animals. This rate, of course, fluctuates
in accordance with the laws of economics, but it is suggested
that if an animal whose condition is 100 be worth 28/- per cwt.,
then one whose condition is 130 should be worth 36/5 per cwt.
In other words, if the rate for the typical store be 28/- that for
any other animal of known condition should be 0°28 C.

When the rate per cwt. is fixed it is only necessary to multiply
by the live weight (in cwts.) to find the actual price. If the
live weight be given in pounds, this would be expressed as
follows :

0:28 C x M
P= SS
112

or, if the formula be substituted for C:

0-28 x 4944x MxM 1-061 M2
pes cea RS ee ot Jee try
| G Tees G )
Hees = OE AD) eS ieee
| 200 200

The rate per cwt. and corresponding price of each of the
animals, calculated by this formula, are shown in Table IIT.

Tt will be seen that No. 302, though classed as fat, is valued
at a slightly lower rate per cwt. than No. 365, which is classed

9

as store. The former, however, is estimated to be worth over
£4 more than the latter because, of course, it is much bigger.

TABLE. IIL,

STORES. Fat BEAstTs.
| Rate | Price. = Late | Price.
No. per Cwt. £33. ds No. per Out, £ nae d.
371 | 28/- i= 0) 6 302 35/8 19 12 5
370 | 29/38 10° ie 5 318 38/8 | 1911 9
359 | 33/8 14 6 1 305 37 /- 93 2 6
365 36/2 1b 7 6 185 37/6 93.18 9

It was not originally the intention of the author to enter upon
the discussion of such practical matters at all. The object was
merely to find some means of testing the condition for purposes
of scientific experiment. Oxen are not infrequently put up to
fatten before they are fully grown, and in such cases any
inferences drawn from the increase in live weight must be of
doubtful validity unless a distinction is made between true
fattening increase and that due to growth.

The question of maintenance rations is also involved. The
feeding standards quoted in the text-books are presumably based
on the requirements of animals in “store” condition, whatever
that may be. It is tolerably certain, however, that more food
is required to maintain an animal in the fat or half-fat condition.
If the rations of a fat beast were reduced to what is required to
maintain it in store condition it would ‘“ go back,” 7.e., it would
lose weight and become thin again. At all events, the results
obtained by different observers cannot be regarded as strictly
comparable unless there be some assurance that the animals
were at least approximately in the same condition. The ques-
tion of maintenance rations is not only of considerable interest
in itself, but it is of fundamental importance in connection with
all feeding trials for any purpose whatever.

Though not favourably situated for collecting data of this
kind, the author has obtained a few additional examples from
three different sources. From the figures given in Table IV it
will be seen that these broadly confirm the conclusions previously
arrived at.

Special importance is attached to the results in group A
(milk cows) because the observations were made by a trusted
*eolleague in the presence of the author, and every precaution

+ Mr. Sidney Pennington, B.Sc., M.R.C.V.S., Lecturer on Agriculture
and Manager of the Farm at University College, Reading.

10

was taken to ensure accuracy. The condition of the animals
was described by practical experts in the following terms: the
bull, very fairly fat; Rose, very good condition; Cherry, good
condition ; Countess, medium fair; Duchess, rather poorer, but
It was considered that the
figures very fairly indicated the relative condition of the animals.

above the average for milk cows.

TABLE LY. ADDITIONAL EXAMPLES.
Group A.—Mu1LK Cows.
Mark. | gilte, | tenet. [oS] — | — | OMe Concition
pounds. | inches. | inches. inches. iar
Duchess 1116 ayy W25 21°46 15:39 70:9 128°5
Countess IB 59 78 DBROINS 17:60 75:6 130°6
Cherry 1456 58 79°5 25°10 18°31 76:3 139°6
Rose 1680 60 86 28:00 19°53 81:3 146:°2
Bull 9044 67 89 80°51 22.97 83:0 156°0
Group B.—SToREs.
il 920 50°5 F(A 18:21 12°96 70°6 109°5
%) 920 50:5 Uf PAO15) 18°21 VETO oak 107°3
3 840 49°5 68 16°95 12°35 | 68:0 105°9
4 896 53:0 72 16:90 12°39 72:0 99-6
5 808 Eile () 68 15°84 11°88 68:4 98:5
6 808 44:0 68 18°36 11-88 67°6 115:9
Group C.—Fat Cows.
1 1995 | 50:5 | 84 | 94:95 | 14:58.) 81-0 ||) ier
y) 1230 49 | 84 95°10 | 14:64 | 80:6 132-2
3 1079 48 } fe botss 22°49 14:48 72°5 Ist loy/
4 1129 48 he DBO IL 15:68 69°7 143°3
5) BES 50 Th) 24:70 15:93 74:5 140°7

* Compared with No. 371 in Table I taken as 100.

In the case of No. 5, group B, it will be noticed that the
In other words it is slightly inferior

condition is less than 100.

to that of No. 371, which was selected merely because it was
the leanest in the first set of data obtained.

If this animal be

dial

accepted as a truly typical store, then the condition of No. 5 is
below par. The average condition of the animals in group B
is 106, and if that be taken as the normal (100) then the con-
dition of No. 371 would be 94:3, and that of No. 5 only 92:9.
The only positive inference that can be drawn is that more data
are required.

In the case of the milk cows (group A) the length was
measured between two vertical standards, one of which was
placed against the point of the shoulder and the other in line
with the extremity of the buttock. In the other cases it was
measured by means of a tape along the back in the usual way.
The latter method is far from satisfactory. It is possible that
the several observers did not determine the points in exactly the
same manner. In that case the different sets of data would not
be strictly comparable one with another, though each set might
be consistent in itself.

So far as it goes, however, the evidence is favourable to the
principle of the method; but, for the present, the formula proposed
(page 7) is offered merely as a hypothesis to be tested. The
essential conditions of such a test are (1) to devise some method
or apparatus for the measurement of length by which exactly
the same results would be obtained by different observers, and
(2) to accumulate a considerable mass of data relating to typical
store and fat animals of different ages and breeds.

Neither of these conditions appears to present any insuperable
difficulties, but they require the co-operation of expert judges of
cattle whose words would be accepted. It is not anticipated
that in order to obtain reliable results it will be found necessary
to take very elaborate precautions such as would render the
method useless to ordinary farmers; but even should this prove
to be the case, the method, if definitely established, would still
be invaluable to scientific investigators and to those who are
called upon to advise farmers.

IBRARY OF CONGRESS

NAIN