Question

What is the difference between inbreeding and outbreeding in cattle? State one advantage and one disadvantage for each one of them.

Answer 1

Hint: Inbreeding means mating of individuals of the same breed or of the closely related individuals. Outbreeding means mating of individuals from different populations, breeds, or species.

Complete Answer:
The difference between inbreeding and outbreeding includes:

Sl.No	Inbreeding	Outbreeding
1.	It means mating closely related superior males with superior females	It is the breeding of the unrelated animals
2.	It occurs within the same breed for nearly 4-6 generations	Two unrelated individuals of the same breed which do not have a common ancestor for the past 4-6 generations are mated.
3.	It helps in maintenance of homozygosity, thereby helping in maintenance of purity of a race	It results in production of hybrids
4.	Repeated inbreeding may lead to a decline in productivity	Repeated cross breeding helps in maintenance of the superiority
5.	The offsprings are not superior to the parents	The offsprings are superior to the parents

Advantages:
Inbreeding increases homozygosity and it is used for developing pure lines (where animals or plants have certain characteristics that are the same through generations). Outbreeding produces hybrids with any desirable character.

Disadvantages:
- Inbreeding in small populations increases the risk of extinction, especially for species that don’t inbreed normally.
- Continuous inbreeding within closely related species, eventually decreases fertility and productivity, and it is called - Inbreeding depression.
- Outbreeding between populations with chromosomal incompatibilities or those adapted to different environmental conditions can also increase the risk of extinction.
- When mating between two genetically different groups or populations results in the reduction of productivity and fitness, it is called - Outbreeding depression.

Additional information: 

There are two more ways by which outbreeding can be carried out: 
- Out-crossing is when Crossbreeding means mating between a superior male of one breed and a superior female of another breed to give an offspring with their combined qualities.
- Interspecific hybridization is when males and females from different related species or species that are incompatible sexually, are mated.

Note: Apart from the routine breeding techniques, to improve the chances of obtaining successful hybrids, programs like Multiple Ovulation Embryo Transfer Technology (MOET) are used.