Effect of barn airspace temperature on composition and technological parameters of bulk milk produced by dairy cows of Czech Fleckvieh and Holstein breeds

Abstract

On two farms (A and B), samples of bulk milk produced by dairy cows of the Holstein (H) and Czech Fleckvieh (CF) breeds were collected every week on the same day within the time interval of 36 weeks. The aim of this sampling was to determine the effect of barn airspace temperature on milk compositon and its technological parameters. The following average values of all bulk milk samples (n = 72) were recorded: barn airspace temperature (BAT) 12.08 °C; rennet coagulation time (RCT) 211 sec.; curd quality class (CQC) 1.53; titratable acidity (TA) 7.16 °SH; protein content (P) 3.46 %; fat content (F) 4.09 %; lactose content (L) 4.79 %; and solids non fat (SNF) 8.86 %. As compared with H, dairy cows of CF breed produced milk with statistically significantly higher (P < 0.01) contents of P (+0.27 %) and SNF (+0.26 %). The remaining differences were statistically insignificant (P > 0.05): BAT (−2 °C); RCT (−4 sec.); CQC (0 class); TA (+0.11 °SH); F (+0.05 %) and L (−0.03 %). As far as the effect of temperature was concerned, calculated correlation coefficients and plotted graphs indicated a marked effect of BAT on RCT; F and P. This effect was in all cases markedly negative: at lower BAT, F and P values were higher and RCT longer while at higher temperatures they were lower and shorter. These trends were similar in both breeds regardless to differences in average values of aforementioned parameters.