| Abstrakt: |
The effects of ration on postprandial serum glucose and insulin were determined in 12 lactating Holstein cows. Six were fed a high grain ration of 15% hay and 85% concentrate (dry basis) and the other six a control ration of 55% corn silage, 10% hay, and 35% concentrate. High grain feeding increased flucose and insulin at all hours postfeeding as compared to control cows. In the cows fed high grain, glucose increased from 63.3 to 72.2 mg/100 ml and insulin from 19.2 to 25.6 muunits/ml serum just before feeding to 3 h postfeeding. Values for 2, 3, and 4 h samples were greater than for other sampling times. Serum glucose was 55.5 mg/100 ml at 1 h in control cows which was above other samples. Serum insulin followed a pattern similar to glucose in controls but was not significantly different with time. The blood changes due to high grain feeding are probably related to low milk fat production. |
