Q.Name the methods employed in animal breeding. According to you which of the methods is best? Why?

The major methods employed in animal breeding are:

• Inbreeding: Mating of more closely related animals within the same breed for 4–6 generations. It increases homozygosity, helping evolve a pure line with desirable characters and exposing harmful recessive genes so they can be eliminated by selection. Continuous inbreeding, however, can reduce fertility and productivity (inbreeding depression) if not accompanied by careful selection.
• Out-breeding: Breeding of unrelated animals, which may be within the same breed but with no common ancestors on either side of their pedigree for 4–6 generations (out-crossing), or between different breeds (cross-breeding), or between different species (interspecific hybridisation).
  • Out-crossing usually produces offspring (called an 'outcross') that show improved yield and heals defects of inbreeding.
  • Cross-breeding allows desirable qualities of two different breeds to be combined; for instance, a high milk-yielding exotic breed can be crossed with a disease-resistant, locally-adapted indigenous breed to get progeny with both good yield and hardiness.
  • Interspecific hybridisation involves mating male and female animals of two different but related species; the mule (from a male donkey and a female horse) is a classic example, though such hybrids are often useful for specific traits rather than routine food production.
• Modern assisted reproductive techniques:
  • Artificial Insemination (AI): Semen from a genetically superior male is collected, stored and introduced into the female's reproductive tract, allowing the wide, controlled use of superior sires without the animals having to be at the same place.
  • Multiple Ovulation Embryo Transfer Technology (MOET): A cow is induced with hormones to produce multiple eggs (superovulation) instead of the usual one, which are fertilised (often by AI) and the resulting early embryos are recovered and transferred to surrogate mothers. This allows a genetically superior female to give rise to many offspring in a short time, rather than just one calf per year. …

List the methods in a logical order — inbreeding, out-breeding (with its three sub-types), then AI and MOET — with a one-line definition of each. For 'best method', argue i …

• Treating 'out-breeding' and 'cross-breeding' as the same term, when out-breeding is the broader category (out-crossing, cross-breeding, interspecific hybridisation are its sub-types).
• Declaring one method 'the best' without justification — the syllabus expects a reasoned, objective-dependent answer. …