Upgrading breeding refers to the use of pure-bred males on inferior females, to genetically improve the progeny.
Upgrading = Use of purebred males to genetically improve inferior females
Take cattle as an example:
A rural farmer with inferior and mixed bred cows can obtain purebred Bonsmara bull for upgrading of his flock.
The genetic improvement by using a purebred Bonsmara bull with continuous crossings happens as follows:
|
Generation |
Bull (% Pure) |
Cow (% Pure) |
Progeny (% Pure) |
|
1 |
100 |
0 |
50 |
|
2 |
100 |
50 |
75 |
|
3 |
100 |
75 |
87.5 |
|
4 |
100 |
87.5 |
93.75 |
|
5 |
100 |
93.75 |
96.875 |
|
6 |
100 |
96.875 |
98.4 |
|
7 |
100 |
98.4 |
99.2 |
Taking into consideration that the first generation (F1) is already 50% improved, and within 3 seasons (F3) the flock improved to 87.5% pure, the following advantages of an upgrading system become clear:
Advantages of upgrading
- It is economically a cheap method of herd improvement
- One good quality male is obtained instead of a whole flock of females
- It is a fast and effective method of improvement
- No expert knowledge is needed
Disadvantages of upgrading
- Male progeny is not suitable for breeding and causes low-income potential
- Improvement decreases after 3rd mating
- 100% pure animals cannot be bred
Weak recessive genes (aa) are dominated by heterozygous (Aa) results using dominant (AA) male genes, for example:
