When the dairy cattle are genetically improved by embryo transfer, generation intervals can be reduced since sires are selected by their full-sister's records rather than by their daughter's records and selection intensity increases because only donor cows and sires for them are selected. In addition by embryo transfer many number of full-sisters and full-sisters are produced at the same time, resulting in the increase in the accuracy of selection.

• 정진관(축산시험장)