Blood Urea Nitrogen in Guernsey Cattle

Abstract

The blood urea nitrogen of 236 Guernsey cows was measured in each quarter for 2 yr. The 12-month mean was 11.83 mg per 100 ml blood plasma (range-2.9 to 22.4). Seasonal changes showed a significant (P < .005) peak in the spring corresponding to pasture; whereas, the lows were observed in the winter months. Advancing age and pregnancy were associated with a decline in blood urea nitrogen. There was no significant (P < .05) difference in mean blood urea nitrogen among daughters of seven sires. © 1966, American Dairy Science Association. All rights reserved.