KAFKAS UNIVERSITESI VETERINER FAKULTESI DERGISI, vol.15, no.6, pp.879-884, 2009 (SCI-Expanded)
The purpose of this study is to estimate the trend components and genetic parameters of 305-day milk yield and lactation length in Holstein Friesian Cattle. The phenotypic, genetic and environmental trends for 305 days milk yield and lactation length were found to be -23.59 kg/year and -0.486 days/year, 7.99 kg/year and -0.49 days/year, -31.58 kg/year and -0.976 day/year, respectively. The heritability and repeatability for 305 days milk yield and lactation length were 0.10, 0.11 and 0.27, 0.17, respectively.