Milk yield, age at first calving and service period in brown swiss and holstein friesian cattle in Turkey

In this research, milk and reproductive yield records of Holstein - Friesian and Brown- Swiss cows of 15 breeding herds in Turkey were evaluated. Least squares means withstandard errors for actual milk yield, 305-day milk yield, lactation length of Holstein Friesianand Brown Swiss cows were, 7160.6±33.0 and 6548.9±47.9 kg, 6729.2 and 6249.4±48.3,330.3±1.5 and 337.5±2.2 day, respectively. Least squares means with standard errors for ageat first calving and days open of Holstein Friesian and Brown Swiss cows were, 845.8±6.6and 908.3±8.6 day, 125.6±3.3 and 127.5±4.1 day, respectively. It was found that herd, parity,breed, calving year and season had a significant effect on actual milk yield (P= 0.00) and 305-day milk yield (P= 0.00). However, the effect of breed on lactation length was insignificant(P= 0.10). The effect of days open on actual milk yield, 305- day milk yield and lactationlength was also found significant (P= 0.00). The effect of days open*breed on actual milkyield (P= 0.85), 305-day milk yield (P= 0.30) and lactation length (P= 0.10) was insignificant.Keywords: Holstein-Friesian, Brown-Swiss, Milk Yield, Age at First Calving, Service Period