Breeding involves applying genetic principles to improve economically important traits in domestic animals. The goal is to produce individuals with superior traits and characteristics, and to develop new traits. Common breeding methods include hand mating, pair mating, and harem mating. Inbreeding involves mating closely related individuals over several generations to develop lines for commercial use. It increases homozygosity but also risks inbreeding depression. Outbreeding introduces new genes by mating distantly related animals. Crossbreeding and backcrossing are used to combine desirable traits from different breeds. Grading up and mutations can also be used to improve animal stock over generations.

1. BREEDING
“It is an application of genetic principles to improving
heriditory for economically important traits in domestic
animals.”
Ex: Improving of milk production in dairy animals
Egg production in chickens

2.  Produce individuals with superior merits
 Improvement of the characteristics.
 Production of new traits.
Advantages

3. Methods
Hand mating
Pair mating
Harem mating

4. Hand mating: In this method male and female are
brought together for a brief period and then separated
once the mating is over.
Ex : Rabbits and Hamsters are mated by this
method

5. Pair mating : This is the method in which male and
females are mated together rest of their breeding life.
In this method in case of mice one male mated with
one female , and left together for the rest of their
breeding life.
In the case of rats, pregnant females should be
isolated prior to delivery.

6. Harem mating : In this method males and females are
run together , but separated prior to parturition
In this method four females are regularly mated with
one male.
The female is separated soon after the pregnancy is
established, and replaced by fresh females.
Ex : guinea pigs are mated by this method.

7. Breeding methods
In breeding
Close breeding
Line breeding
Out breeding
Out crossing
Cross breeding : Criss crossing
Triple crossing
Back crossing
Grading up
Mutations

8. INBREEDING
“The crossing of two closely related genes is called
inbreeding.”
In this individuals are mated 4-6 generations.
Objective
Develop lines which commercially used.
Inbreed should have at least 50% coefficient of inbreed.

9. Advantages
 It is used to return desirable genetic characters.
 Identify harm full genes.
 Increase frequency of homozygocity .
Disadvantages
 Higher susceptibility to genetic disorders.
 Risk of inbreeding depression I . e infertility , delayed
maturity , slow growth , decrease egg production.
 hybrid vigor and fertility were lost due to repeated
inbreeding.

10. Line breeding : This is the breeding of animals that share
common ancestors but are not closely related.
 Line-breeding over successive generations will result
in more variations of physical appearance
Close breeding : In this mating the breeding is done
between brother-sister , dam-son etc.

11. Out-breeding
 The crossing of distantly related animals is called
Out -breeding.
 In this method it is possible to breed a desirable type
of animal with a less desirable type and then to
increase the degree of desirable traits.
Advantages :
 New and high yielding genes can be introduced into
the population through out -breeding.
 They produce some valuable traits
 Can create new breeds
 Can produce a hybrid of superior vigor and value.
Disadvantages :
 Introduction of new genes into population.

12. Out – crossing : It is system of mating where un related
animals with in the same breed.
Cross breeding :
a) Criss cross : Mating of two different breeds
alternatively.
In pigs
Hampshire Vs Landrace
Progeny 1 Vs Hampshire
Progeny 2 Vs Landrace
It can produce pigs with different levels of inheritance.

13. b)Triple crossing : mating of three different breeds in
rotational manner.
 Cross breeds have different proportions for all three
breeds.
Hampshire Vs landrace
• Progeny 1 Vs large black
Progeny 2 Vs Hampshire
Progeny 3 Vs Landrace

14. c)Back crossing : Mating of cross bred animals to one of
pure bred parents which were used to produce them.
Aa Vs AA
2AA , 2Aa
Grading up:
 It is the system of breeding purebred sire to non
descript breed generation after generation.
 Level of exotic breed inheritance increase upgraded
stock up to 99% in the 7th generation.
 Selection and breeding are two main tools to produce
superior individual.

15. “sudden change in the genetic material”
The new traits into populations can also be induced
through mutations.
Most of the mutations are harmful and the process of
induction of this method of improvement of animals is
impractical.
Eg : poultry that is resistant to white diarrhoea ,
increased egg production in fowls, increased fat
content in milk and better meat yielding in Turkeys etc.
Mutations

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