Influence of Some Management Practices and Season Upon Freezing Point of Milk

A group of 12 cows fed a low-forage ration produced milk which had a freezing- point 0.003C colder than a similar group of cows fed the normal amount of forage but less grain. Milk from all cows had a colder freezing point toward the end of their lactation and all showed warmer freezing points during July. Lactations were completed in August to November. The weighted average freezing point of individual cows’ milk had a slightly lower freezing point than the composite taken from the bulk tank but as the milking process continued, the weighted average and the composite freezing points were closer together. Movement of milk from the weigh jar to the bulk tank was found to cause a change in the freezing point equivalent to addition of approximately 0.1% added water. There was no significant difference in freezing-point depression of milk from cows fed three different types of hay. Milk from cows consuming high-moisture silages (corn and sorghum) had a significantly warmer freezing point than those fed a low-moisture silage (alfalfa).