RESUMEN
Biweekly Grade A and manufacturing grade herd milk samples were collected from April 1, 1985, to March 31, 1986, from 203 herds in the Sioux Falls, SD, area and were analyzed to compare composition. The average herd milk composition was 3.70% fat, 3.24% protein, 4.80% lactose, 0.63% ash, 8.67% solids-not-fat (SNF), and 12.37% total solids (TS). Grade A milk had higher % lactose (4.83 and 4.76), % SNF (8.70 and 8.61), and % TS (12.41 and 12.30) than manufacturing grade milk. These compositional differences between grades were consistent throughout the year. Grade A milk has more value in the production of dried dairy products (nonfat dry milk and whey powders) and ice cream than manufacturing grade milk due to its higher lactose and SNF content. New milk pricing plans for protein and other constituents should consider compositional differences (lactose, SNF and TS) that exist between grade A and manufacturing grade herd milk before implementing them.