Metabolic profiles in Virginia dairy herds of different milk yields.

This study examined metabolic profiles of commercial dairy herds differing in milk production. Thirty herds were selected with 10 herds averaging more than 7258 kg milk, 10 herds between 6350 and 7258 kg, and 10 herds averaged below 6350 kg. In each herd, 28 cows were selected for blood sampling, which was collected every 3 mo during 12 mo. Cows varied in estimated relative producing ability. Metabolic profiles were established for 19 blood components. Differences among treatment means were significant between high and low producing herds and little between profiles for milking and pregnant nonlactating cows. Metabolic profiles of problem herds remained within normal ranges for all herds except one. Profiles of herds with breeding or mastitis problems remained in the normal range. Metabolic profile testing was of limited value in screening a dairy herd for potential problems or deficiencies.