Maharashtra Board Class 11 Animal Science And Technology Chapter 11 Animal Breeding And Selection PDF Download

11. Animal Breeding And Selection

Can you recall?

Terms: Breed, breeding and selection

11.1 Systems Of Breeding

The animal breeding programmes involves selection of superior animals and mating them to obtain progeny with better genetic potential.

The combination of effective selection with proper mating / breeding system is essential for success of any breeding programme.

Objectives Of Animal Breeding

1. To increase production of milk, meat, egg and wool.

2. To improve growth rate.

3. To improve quality of milk, meat, egg and wool.

There are two main systems of breeding:

1. Inbreeding.

2. Outbreeding.

11.1.1 Inbreeding

Inbreeding is the mating of related animals.

Advantages

1. It increases homozygosity and decreases heterozygosity.

2. It helps in producing seedstock (elite animals) for crossbreeding.

3. It helps in development of families or inbred or purebred lines.

4. It helps in elimination of undesirable recessive genes.

5. It increases uniformity of productive characters.

6. It helps in selection of desirable animals and also culling of undesirable animals.

Disadvantages

1. It decreases growth rate, body size and body weight.

2. It reduces reproductive efficiency and production performance of the progeny.

3. It slows testicular development, reduces vigor in males and delays puberty in both sexes.

4. It increases early embryonic death rate and mortality in progeny.

Teacher's Note

Inbreeding helps make animals uniform and pure. For example, farmers in India use inbreeding to make better milking cows in their village herds.

Exam Trick

Remember: Inbreeding = related animals mating = more uniform but weaker babies. Just like if cousins marry, the children may look the same but could be sickly.

Points to Remember

Inbreeding means mating of related animals.
It increases homozygosity in the progeny.
It helps find and remove bad genes.
It causes inbreeding depression when used too much.
It can make animals weak and sick over time.

Remember

The decreased growth and reproductive efficiency due to inbreeding is termed as inbreeding depression.

The inbreeding depression results from homozygosity.

Introduction To Scientist

The origin of animal breeding lays in the United Kingdom. Robert Bakewell (1727-1795), who introduced keeping accurate records of performance of animals so that objective selection and breeding became possible. He was the first scientist to improve animals for meat production and carcass quality.

Teacher's Note

Robert Bakewell was the father of modern animal breeding. He kept records of which animals produced better meat, just like farmers today keep records of which cows give more milk.

Exam Trick

Remember: Robert Bakewell = record keeping = the start of modern breeding. Think of him as the first farmer to write down which animals were best!

Points to Remember

Robert Bakewell was born in 1727 and died in 1795.
He started keeping animal performance records.
He worked with animals for meat production.
He improved the carcass quality of animals.
He made objective selection and breeding possible.

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