Non-genetic factors affecting milk and reproductive traits of Swedish Red and White cattle raised organically in Turkey

The data on breeding and performance records of Swedish Red and White (SRW) cows kept in a private organic dairy farm in Kelkit, Turkey, during the period from 2006 through 2009 were used to study the effect of some non-genetic factors such as calving year, calving season, parity, age of dam and sex of calf on the various milk and reproductive traits. The actual lactation milk yield, daily milk yield, peak daily milk, days to attain milk yield and lactation length averaged as 5887.2 +/- 94.9 kg, 19.9 +/- 0.3 kg, 31.5 +/- 0.3 kg, 79.4 +/- 2.7 days and 302.5 +/- 3.2 days, respectively. The actual lactation milk yield, days to attain peak milk yield and lactation length were significantly affected by calving year and calving season. The effect of the parity on the daily milk yield, peak daily milk yield and days to attain peak milk yield were significant (P<0.01). The least squares means for calving interval and gestation length were 380.2 +/- 4.3 days and 275.4 +/- 0.6 days, respectively. Age of dam and calving season significantly (P<0.01) affected the days open. Mean age at first calving of SRW cows raised organically was 26.4 +/- 0.2 months and was significantly affected by the calving years. Significant (P<0.01) and positive phenotypic correlations of the actual lactation milk yield with daily milk yield (r = 0.71), peak milk yield (r = 0.53), lactation length (r = 0.53), days open (r = 0.43), calving interval (r = 0.36) and days attain to peak milk yield (r = 0.14) (P<0.05) were determined. In conclusion, the significant effects of environmental variables must be taken into consideration when developing and comparing models to be used in adjusting data to provide the best estimates of genetic values and parameters in evaluation of SRW cattle reared organically in Turkey.