Market share for semen and cloned embryos in dairy herds.

Use of cloned embryos from desirable genotypes (commercial clone lines) enables faster dissemination of superior genetics to dauy producers. Under optimal purchasing strategies of milk producers, the annual proportion of replacement cows from commercial clone lines indicates the market share of cloned embryos compared with semen. Relevant factors affecting this market share were studied. To produce the next generation of commercial cows, the nucleus provided semen from the best sire and cloned embryos from the best female genotype, were selected for a trait associated with lactation. A commercial cow was inseminated if net returns from her expected offspring were higher than net returns from an expected contemporary clone. Net returns equaled net milk returns minus the costs required to breed an expected offspring. If not inseminated, a cow could be used for implantation of a cloned embryo. An increase in the genetic difference between cloned embryos and semen or in the annual additive genetic response achieved in the nucleus increased market share of cloned embryos. Market share decreased as the difference in costs required to breed an offspring from AI or implantation increased. In addition, market share was affected by characteristics of the commercial cow population before the introduction of clones.