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Agriculture for Secondary Schools

in the form of grass, hay or silage. These forages may not have enough nutrients
to meet the animal requirements. In such a situation, supplementary feeding is
provided in a form of concentrate mixture. In Tanzania, the common supplementary
feed mixture includes maize bran, wheat bran, rice polishing/bran, cotton seed cake,
sunflower seed cake, molasses and mineral-vitamin mixture as shown in Table 5.2.

Table 5.2: Ingredients commonly used in supplementary feeds
Common feed stuffs Type of nutrient

Cereal grains and cereal milling by-products Energy
Oil seed cakes, fish meal, blood meal, meat meal, green Protein
leguminous fodder and pulses

Bone meal, oyster shells, eggshells and mineral rocks Minerals
Mineral-vitamin mixture Vitamins and minerals

Feed formulation for supplementary feeding
Feed formulation requires the knowledge of requirements of the animal type and
class as well as nutritive value of the ingredients to be used. This information is
obtained from tables of feeding standards. When formulating a feed, one targets to
obtain a balanced ration for a given class of animal. A ration is the amount of feed that
an animal can consume and obtain all the nutrients required in 24-hour period. There
are several techniques for feed formulation. The commonest approach is the Trial-
and-Error and Pearson’s square. The linear programming method is an advanced
method where rations are balanced on the basis of Least Cost formulations. In this
section, you will learn about a simple approach of mixing two ingredients, popularly
known as Pearson Square method.

Example of Pearson Square method of formulating feed
Suppose you wish to have a supplementary ration for a high yielding cow containing
20 % Crude Protein (CP) by mixing maize bran and soya bean concentrates. The
following steps have to be followed.
Step 1: Find the value of CP in soya bean meal and in maize bran from feed tables:
(soya bean meal is shown to have 40 % CP and maize bran has 10 % CP).

Step 2: Place the required percentage at the centre of a square and values.
Soya bean 40% CP 10 parts of soya bean

20%

Maize bran 10% CP 20 parts of maize bran
30 Total parts

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