5.11 Breeding animals

Understand that animals with desired characteristics can be developed by selective breeding

Cow ---> Desired character = milk yield

Earliest farmers noticed that a few cows (A) would produce a small amount of milk each time, for example, 50 ml. A few other cows (B) would produce a 150 ml of milk. Most © would be producing a 100ml of milk.

The farmer will collect all the milk, but it would be cows C that he would choose to become his breeding cows. 

In the next generation of cows, we find that a few cows are producing 100 ml, a few with 200 ml (D) , and most with 150 ml of milk. 

The farmer then will select cows (D) as his breeding cows. 

Cows that produce high yield becomes the breeding population --> selected for the desired characteristic.

In the 3rd generation, it would be ranged with 150 --> 200 --> 250. 

As we progressively select, we change the desired characteristic. We are able to develop the desired characteristic by selective breeding. 

For this to work, recall that milk yield must be under the control of genes (genetic).