Analysis of factors affecting the electric conductivity of cow's milk--breed, locale, season

The problem was studied in a set of 678 mammary glands of 212 cows - crossbreds between the Holstein-Friesian breed with the Slovak Spotted cattle, crossbreds of the Black-Pied Lowland and Bohemian Spotted breed, and three-way crossbreds of the Black-Pied Lowland, Swedish White and Bohemian Spotted cattle. The confrontation of the confidence intervals of milk conductivity (MC) in healthy mammary glands at alpha = 0.05 showed that in the crossbreds of the Black-Pied Lowland cattle the MC was statistically significantly higher than in the breed types of the Holstein-Friesian cattle. The MC values decrease when there is a larger proportion of the blood of beef-and-dairy cattle (Slovak Spotted and Bohemian Spotted breeds). The locality where the stock was kept was found to act as an important factor underlying MC only in cases when both the geographical conditions and breed proportions were different. In a set homogenized with respect to the breeds, statistically significant differences in MC were demonstrated between the spring and summer season, spring and autumn, summer and autumn, and autumn and winter season.