ESTIMATION OF
LIVE WEIGHT OF FARM ANIMALS USING
THEIR BODY
MEASUREMENTS
The estimation of
liveweight of farm animals is essentially required for various purposes such as
for calculating feed requirements, for estimating gain or loss in body weight,
for finding out rate of growth in younger animals, and for determining
show-ring classification. The use of weighbridge, etc., for this purpose is not
only cumbersome and costly but also the weighbridge may not be available at all
places. Therefore, only such methods that are cheap, simple and yet accurate
can be useful for extensive use even under field conditions.
Given below are some of the formulae
developed by various workers for the estimation of liveweight of farm animals
using their body measurements:
G2 x L
i) W =
 |
Where,
|
300
|
|||
W
|
=
|
liveweight of cattle in pounds;
G = heartgirth in inches, and
|
|||
L
|
=
|
length of
cattle from the point of shoulder to the point of pin bone
|
|||
ii)
|
W
|
=
|
(G + L)²
|
||
x
|
|||||
Where,
|
|||||
W
|
=
|
estimated weight of goats in
pounds,
|
|||
G
|
=
|
girth of goats in inches, L =
length of goats in inches, and
|
|||
X
|
=
|
17.0 when the girth ranges from
15-19 inches,
|
|||
X
|
=
|
13.5 when the girth ranges from
20-25 inches, and
|
|||
X
= 12.0
when the girth is more than 25 inches.
iii)
a)
For Murrah calves
r
= 0.084X1
+ 0.306X2 + 1.723X3
– 30.247
b)
For
Sahiwal calves
r
= 0.259X1
+ 1.198X2 + 0.448X3
– 17.024
Where,
r = birth
weight (kg), X1 = length in
inches,
X2
= height in inches and X3
= girth in inches.
iv)
a)
For
Damani sheep
Y
= -79.2496 + (1.1737) X1
+ (1.9096) X2 + (1.6343)X3
b)
For
Thali sheep
Y
= -234.6704 + (14.6005) X1
+ (5.5723) X2 + (9.2750) X3
Where,
Y
|
=
|
liveweight in pounds, X1 = height in inches,
|
X2
|
=
|
girth in inches and X3 = length in
inches.
|
a)
Two
to five years old:
Y
= -1697.226 + (16.761) X1
+ (23.947) X2 + (0.514) X3
b)
Six
to eight years old:
Y
= -1604.790 + (1.268) X1
+ (30.902) X2 + (3.960) X3
c)
More
than 8 years old;
Y
= -1263.663 + (8.060) X1
+ (18.924) X2 + (8.565) X3
Where,
Y
= Liveweight in pounds, X1
= height in inches, X2
= Girth in inches, and X3
= length in inches.
In taking body
measurements such as height, heartgirth, length, it is important that the
animal be kept off feed and water for several hours prior to measuring it; the
animal stands with all four legs squarely under the body and with the head held
up in a normal position and that the measuring tape be passed around the body
just back of the shoulders at the smallest circumference and pulled up
reasonably.
A weight tape is a simple and effective
way to estimate a horse’s weight at fraction of the cost of a weight scale and
with minimal effort.
The weight is determined by wrapping the
tape around the heart girth of the horse, directly behind the elbow,
overlapping the ends of the tape, and reading the resultant weight. The reading
should be taken with the tape snugly in place, at the time of respiratory
expiration.
Tape accuracy is
dependent on the user, the breed of horse and age. They are useless on
miniature horses and foals. They are also inaccurate on high withered horses.
However, on the average horse, they estimate the weight of a horse more
accurately than most owners.
Body
Measurements Using Weight Tape
Various body
measurements are used single or together to estimate the body weight of horses.
The weight tape normally uses the girth measurement. The girth measurement
alone has a correlation of 0.87 (P<0.01), while girth and length has a
correlation value of 0.90.
Adult horses
|
||
Wt. (kg)
|
=
|
[(girth)² x length] ÷ Y
|
Where Y
|
=
|
11900
|
(measurements are in
centimeters)
|
||
Foal weight
0-60 days
|
||
Wt. (kg)
|
=
|
[heart girth
in inches -25] ÷ .07
|
The average
Thoroughbred foal will double its weight in the first 28 to 35 days.
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