Estimation of phenotypic and genetic parameters of milk yield and fertility traits of simmental cattle reared Gökhöyuk state farm

In this research, fertility and dairy production traits of Simmental cattle breeds reared at Gokhoyuk state farm in Turkey were evaluated. The data relating to milk yield traits in the period of 2007-2014 of a Simmental herd reared Gokhoyuk state farm used Preliminary analyses were performed to identify signifi cant fixed effects on milk yield and fertility traits using Minitab (Version 12) statistical program. Estimation of variance components and genotypic parameters for milk yield traits and reproductive traits were obtained by using "MTDFREML" breeding program. Means for actual milk, 305 day milk yield (305-dmy) lactation length, calving intervaland service period were determined as 4363.01 64.790 kg, 4181.47 60.122 kg and 322.92 2.432 days, 367.37 2.840 and 116.45 3.433 days respectively. The heritabilities of actual milk yield, 305-dmy, lactation length, calving interval and service period were, 0.17±0.080, 0.18±0.015, 0.02±0.035, 0.02±0.010 and 0.01±0.0035, respectively. Repeatabilities of the same characteristics were found as; 0.19, 0.20,0.03, 0.02 and 0.02 respectively. The genetic trend for 305-dmy of Simmental cattle were 30.3 kg/year, respectively. Consequently, it can be said that the determined variance components, genetic parameters and breeding values could be used as selection criteria and to in crease the success of the selection in breeding researchs for Simmental herds in Turkey. Keywords: Simmental, Genetictrend, Heritabilities, Repeatabilities,