Author: Arnold Ray HippenPublisher:
ISBN:
Category :
Languages : en
Pages : 276
Book Description
To test the hypothesis that glucagon will decrease the severity of fatty liver and prevent ketosis, glucagon was continuously infused via intravenous jugular catheters into dairy cattle in several physiological states. In preliminary dosage response studies, glucagon was infused into eight spayed Holstein heifers, four midlactation Holstein cows, and four early-lactation Brown Swiss cows in cross-over design trials at dosages of 20 mg/d or less for 48 h. Plasma glucose concentrations were increased by glucagon in a dose-dependent manner. Plasma nonesterified fatty acid and ketone body concentrations were not increased by glucagon at 5 mg/d or less, were increased in heifers at 10 mg/d, and increased in cows at 20 mg/d compared with preinfusion concentrations. Glucagon at 10 mg/d was the largest dosage tested in lactating cows that did not elicit a lipolytic or ketogenic response. Glucagon at 10 mg/d or vehicle then was infused for 14 d during a protocol to induce ketosis in 20 early-lactation Holstein cows already having fatty livers.