Abstract

The solid fat content of milkfat has a major influence on the hardness of butter produced at dairy factories. The aim of this work was to study the variation in the solid fat content of milkfat from thirty herds in the factory collection area on a single dayto determine the extent of variation in the milk supply. The solid fat content of the milkfat at 10°C varied from 49.6% to 59.8% between the individual herds. This variation in the milk from different herds is as large as the entire seasonal change observed in the bulked factory silo milk, indicating significantvariation in the properties of the milkfat within the factory supply on a single day. Low solid fat content at 10°C was correlated with milk of low fat percent (r = 0.78, P< 0.0005) and high protein-to-fat ratio (r = -0.75, P< 0.0005). Though there was substantial variation in the solid fat content within the breeds, milkfat from Friesian herds had a significantly lower solid fat content than milkfat from Jersey herds (mean ± S.E., 54.4 ± 0.6 and 57.1 ± 0.6 respectively, P = 0.004). There appears to be considerable potential for exploitation of the natural variation in the properties of milkfat inherent in the New Zealand dairy herds.

RA, Sherlock, LA Smith, and RS Mitchell

Proceedings of the New Zealand Society of Animal Production, Volume 56, , 228-229, 1996