Crossing Indian cattle with foreign breeds is done in many ways.
1. Forming a new gene pool.
Some cattle from the two breeds are mated to form new group of breeds with
desired proportion of foreign blood (genes). Again, the cattle of the new gene
pool group (in the next generation) are mated with one of the two first breeds
to form another gene pool.
2. Systematic crossing
In this method, each generation the breeding animals of both Indian and foreign
cattle are mated to form the new breed. Also, three-way crossing of cattle with
a second stage of crossing is also done. This is called terminal crossing. Also
rotational crossing techniques are used to mate alternately. Male parents
(sires) of the temperate and tropical breeds are used in alternate generations.
3. Crossing the cross-bred sires
The half-bred sires are produced in each generation. Those are mated to
enhance the grade of Indian female cattle. So the female population with
foreign blood will increase.