Abstract
Abstract. Direct and interactive effect (individual and maternal heterosis) was estimated using data from rotational crosses between Holsteins with Iranian native breeds. Traits of interest were milk yield, fat yield, fat percent and milk days. Complete data were available on 155240 animals from 1991 through 2003. Direct additive’s effect, individual heterosis, maternal heterosis and recombination (interactions between presences of Holstein gene in two parents) effects were estimated by multiple regression method in SAS 8.2 with mixed models procedure. The least squares means of milk yield, fat yield, fat percent and milk days were 2722.68±1 541.12 kg, 122.97±47.40 kg, 3.97±0.73 percent and 260.10±89.51 days respectively. All direct and indirect genetic effects are significant in milk and milk days traits (P<0.05). Individual and maternal heterosis and recombination effect are not significant on fat yield and fat percent traits. The individual and recombination effect were negative effect on milk yield. The result suggested that the Holstein is a favourable breed for crossbreeding program in developing country as Iran.
Highlights
With the increasing population in worldwide and need to increase milk production, the introduction of high-yielding breeds (i.e. Holstein-Friesian) plays an important role in protein needs supplying
The overall least squares means for milk yield, fat yield, fat percent and milk-days traits were 2 722.68±1 541.12 kg, 122.97±47.40 kg, 3.97±0.73 percent and 260.10±89.51 days respectively which were in agreement with the means reported by Rekui (2000) and Naji (1996) in Holstein Friesian × Golpaigani cows
The effects are Ghorbani and Salamatdoustnobar: Estimation of non additive effects on milk production traits presented with their SE and P-value obtained directly from the regression models
Summary
With the increasing population in worldwide and need to increase milk production, the introduction of high-yielding breeds (i.e. Holstein-Friesian) plays an important role in protein needs supplying. Crossbreeding as a mating system optimizes the additive genetic and nonadditive (heterotic) breed effects of Bos taurus and Bos indicus cattle in sustainable breeding systems (Gregory & Cundiff 1980). Knowledge of the maternal contribution to the performance of the offspring is necessary in planning sound breeding programs (Cassady et al 2002, Solnker 1993, Vostry et al 2008). Despite the high population of crossbred’s cattle, a little estimates of breed and heterosis effects on productive traits have been reported, Rekui (2000) carried out first estimates of heterosis effects on the
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