AGB 211: Livestock and Poultry Breeding (2+1)

METHODS OF CROSS BREEDING

Single two way cross or Single cross

• Two different breeds are crossed with each other to produce an F₁ which is useful for production purposes and not for breeding.

 

Breed A and Breed B : Straight bred

F₁ progeny AB : Crossbred

Three way crosses (A,B, C)

• The first generation crossbred females are crossed with females of the third breed, then using the hybrid vigor of dam.

Double cross or Four way cross

• There are four breeds are involved in this type of crossbreeding programme. First two breeds are crossed to get F₁ and second two breeds are crossed for getting another F₁ the both F₁s are crossed to produce F₂ which having 25% of genes each from four different breeds, so all the different characters are combines well. By inter-se mating the selected characters are fixed in the four way cross

Systematic cross breeding

• Back cross (AB)
• Usually the F₁ females are back crossed to one of the parent breeds. In this cross, the maternal heterosis is exploited.

• Criss crossing (Reciprocal back crossing)
• Breeds A and B are crossed to produce F₁ generation, then F₁(AB) females are back crossed to B and F₁ (AB) males back crossed to breed A and so on.

Three way rotational cross

• Commercially used in pig industry.
• Breeds A, B, C are crossed in tradition.

• Three way rotational crossing maintain a high degree of heterozygosity. For three way rotation, frozen semen/sire can be used without maintaining purebred population.