Analysis of population and heterosis effects in crossbred cattle of Czech Fleckvieh and Beef Simmental parentage for growth traits

Abstract. Genetic effects, e.f. population and heterosis effects have been estimated for: Czech Fleckvieh, Beef Simmental and various types of their crosses produced in beef cow-calf operations. The best genetic-statistical model was chosen for the analyze of these effects. The fallowing traits were analyzed: birth weight, weights at 210 and at 365 days of age as well as average daily gains between birth and 210 days, between 210 and 365 days and between birth and 365 days of age. Parameters for all the traits were estimated by the method of least squares means with fixed effects year of birth, herd, sex, type of birth (single or multiple), age of dam and genotype. Genetic models involved the means and two to four crossbreeding effects: i.e. direct and maternal population effect and direct and maternal heterosis effect. The results showed that the genetic model including the mean and all four crossbreeding effects was more accurate and advantageous that the others. For all growth traits crossbreds exceeded both purebred populations. Positive values were estimated for most direct and maternal population effects. Direct and maternal heterosis effects in global showed negative values.