ANIMAL HUSBANDRY
Estimate the weight of livestock
K
nowing the approxi-
mate weight of one's
animals is useful in a
number of circumstances, for
example when calculating
doses of medication o r the
size of feed portions, or when
transporting them by vehicle,
but few smallholders have a
scale robust enough for the
task.
If you only have a few
animals to weigh and a high
degree of accuracy is not
needed, you can get a good
estimate of an animal's weight
using only a measuring tape
and a calculator.
In most cases you will be
measuring the heart girth and
the length of the animal and
then using a formula to
estimate its weight.
K Pigs
If you have a pig, this is what
you will do.
While the pig is busy eating
and completely uninterested
in what you are doing, place
the tape measure under the
pig just behind the front legs
over the pig's heart and
measure the circumference of
the pig's girth in metres (or
centimetres divided by 100).
This measurement is known
as the Heart Girth.
Then measure the Length of
the pig along its back from
the base of its ears to the base
of its tail, again in metres.
Then use the following
formula. Square the Heart
Girth to get the Girth Result.
Now multiply the Girth Result
by the Length and multiply by
69.3. You now have the
weight of your pig in Kg.
Example:
K Porky Pig has a Heart Girth
of 1.27m and a Length of
1.02m (127cm
35
www.sasmallholder.co.za
divided by 100 and 102cm
divided by 100).
K Square the Heart Girth
(1,27 x 1,27) = 1.6129 =
Girth Result
K Multiply the Girth Result
(1,6129) by the Length (1,02)
and multiply by 69,3 = 114
Kg.
This procedure is reported to
be accurate to within 3%.
Continued on page 37