Authors: ZAFER ULUTAŞ, NUMAN AKMAN, ÖMER AKBULUT
Abstract: In this study, the data consist of 305-day milk yield, calving intervals and pedigree information regarding Holstein cows raised on the Gelemen state farm and calved between 1982 and 1997. Estimates of genetic parameters and variance components of 305-day milk yield and calving intervals were obtained by restricted maximum likelihood analyses fitting an animal model. Heritabilities of milk yield and calving intervals were 0.16 ± 0.055 and 0.058 ± 0.0436, and the replications of the same traits were 0.35 ± 0.031 and 0.058 ± 0.040, respectively. While the genetic correlation between 305-day milk yield and calving intervals was high (0.69 ± 0.300), phenotypic correlation was rather low (0.18 ± 0.033). High, positive correlation between 305-day milk yield and calving intervals was interpreted as an increase in 305-day milk yield causing a decrease in calf number per time unit.
Keywords: Genetic parameter, calving intervals, 305-day milk yield, Holstein-Friesian
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