The size of the genetic improvement from generation to generation depends on the technique used to select animals for breeding. Introduction of new selection techniques made it possible to select the best animals for breeding more accurately and efficiently. Especially the introduction of reproduction techniques like artificial insemination (AI), that made it possible to have (very) large numbers of offspring per sire , made it possible and to select only the very best males for breeding. In females techniques like embryo transplantation (ET) or ovum pickup have made it possible to produce much larger number of offspring of excellent females than with normal reproduction techniques in this species where normally only one or few offspring per year were feasible. The wide use of these reproduction techniques resulted e.g. in a steady increase of the milk production per cow.
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