Abstract
Closed-herd breeding plan by embryo transfer method (ETM) was presented and its genetic gain in breeding stock was compared with that by conventional method (CM). On the genetic progress of growth trait in CM, calculation was done under two circumstances, one, no female selection at all and the other, female selection rate at 67%. In the latter, it takes 8 years in ETM to improve one standard deviation unit on a growth trait, while 14 years in CM, assuming the genetic correlation between growth trait and carcass trait is zero. It takes 8 and half years and 15 years, respectively, in the case when the genetic correlation is -0. 2. To improve one half standard deviation unit on a carcass trait, 12 years are required by ETM, while 18 years by CM, assuming the genetic correlation between two traits is zero. On the contrary, negative correlated response pulls down the speed of genetic improvement of ETM on the carcass trait to the extent of CM, in case when the genetic correlation is -0.2. Hence, it was concluded that the breeding plan by embryo transfer would exceed the conventional one, by shortening the time per breeding cycle with introduction of sib test instead of progeny test and by increasing female selection rate as well on the growth trait.
