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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.