Abstract
This investigation was conducted to grasp the outline of occurrence of low fat milk in the field. About one hundred and twenty samples a month were collected from dairy farms in Noto area of Ishikawa Prefecture for one year and fat and solids-not-fat contents in milk were determined for each samples. Both fat and solids-not-fat contents in milk reached the highest 3.81±0.26 (mean±standard deviation) and 8.53±0.45% respectively in January, and the lowest 3.33±0.30% and 8.16±0.22% respectively in August. The milk of lower fat and solids-not-fat contents than 3.2% and 8.0% respectively appeared most frequently in summer months. It seemed that the major cause of low fat milk production was the heat stress in summer.
