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Agriculture for Secondary Schools

(c) increase resistance of an animal against diseases.
(d) increase animal adaptability to environment.

It is important to know that the performance of the animal is not only affected by

genetic constituent but also by the environment in which it is reared. The environment
in this case includes feeding, housing condition, temperature surrounding it, water
availability, parasites and diseases as well as any other factor within the surrounding
in which the animal lives. However, inferior animals will not perform beyond
their genetic limits even if they get best feed and other management requirements.
Therefore, improvement of genetic make-up of animals is important at all levels of
management. For example, improvement in management in terms of nutrition and

health will be meaningful if the animals will be bred to produce an offspring that
has an ability to better utilise that feed type and adaptive to the given environment.

Selection
For a breeding system to give good results, it has to go together with proper selection
hence, selection and breeding systems are also termed as tools for improving genetic
make-up of livestock. In using these tools, different animal traits are identified,

selected, measured and the best ones are used as parent animals. In selection process,
certain individuals are chosen to be the parents of the next generation based on their
desirable characteristics. The principle is ‘keep the best and cull the poorest’. In
farms, various factors are considered in identifying the individuals to be selected
mainly on the basis of observable and measurable traits.

Factors considered in selecting the animals
(a) Age of the animal: Priority is given to young animals as they have longer
productive life than old ones because the efficiency of breeding declines with

age.
(b) Performance level: Animals with highest production records should be selected
first.

(c) Health status: Animals which are healthy, disease resistant and free from
abnormalities should be selected as they pass on to their offspring.
(d) Quality of products: Selected animals should come from those which produce
high quality products.

(e) Body conformation: Animals selected should be those with desired conformation,
e.g., wedge shape for dairy cattle and block shape for beef cattle.

Student’
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