GENETIC PROGRESS AND RATE OF INBREEDING IN A CLOSED ADULT MOET NUCLEUS UNDER DIFFERENT MATING STRATEGIES AND HERITABILITIES

Monte Carlo simulation was used to investigate genetic progress and rate of inbreeding in a closed adult MOET (multiple ovulation and embryo transfer) nucleus breeding scheme under different mating systems, different nucleus sizes and various amount of information for evaluation. Simulation results showed that the factorial mating design, where each dam is mated to more than one sire, will increase genetic progress without much effect on the rate of inbreeding. Rate of inbreeding was decreased by selecting more than one male from a full-sib family. The best response with low rates of inbreeding was achieved when applying these two strategies simultaneously. Adding further information via progeny tests from outside the nucleus or later lactation records had only a moderate effect on the rate of inbreeding. It affected the genetic progress especially under factorial mating design and most clearly when the heritability was low. A combination of juvenile and adult MOET breeding schemes proved to be the best scheme for high heritability traits, but lead to higher rate of inbreeding than the conventional adult MOET scheme.