AGB 211: Livestock and Poultry Breeding (2+1)

INTRODUCTION

• The purpose of animal breeding is not to genetically improve individual animals but to improve future generation of the animal population. The method used by the breeder to make long-term change in animals is called selection. Selection is the process in which certain individuals in a population are given an opportunity to produce offspring while others are denied this opportunity. It also decides about how many offspring it should produce and how long they should remain in the breeding population. Selection is an important tool for changing gene frequencies to better-fit individuals for a particular purpose. Selection is not an invention of modern man. It has been going on in nature since life existed in the world. Selection is choosing of individuals that will be parents of next generation.
• Effectiveness of selection depends on ability to recognize those animals, which possess superior inheritance. Those superior animals must be mated together for the production of offspring. The aids available to estimate the breeding value of an animal is through the phenotype of an animal or its relatives.

• Various aids available for selection are: (a) Individual selection or mass selection, (b) Pedigree selection, (c) Progeny testing and (d) Family selection and sib selection.
• Breeders always tend to go for selection of several traits at a particular time. Because, the net value of an animal would depends on several traits that may not be equally economically important. The desirable trait will depend on the economic value but only of real importance may be considered. If too many traits selected for one time there will be less progress in improvement of any particular trait. There are three methods of selection viz., tandem method, simultaneous but independent culling level method and selection index method.