Effects of in vivo administration of growth hormone on milk production and in vitro hepatic metabolism in dairy cattle

• Published in: Journal of dairy science Vol. 69; no. 3; pp. 713 - 720
• Main Authors: Pocius, P.A, Herbein, J.H
• Format: Journal Article
• Language: English
• Published: United States Am Dairy Sci Assoc 01.03.1986; American Dairy Science Association
• Subjects: Acetoacetates - blood; ACIDE GRAS; ACIDOS GRASOS; Alanine - metabolism; Animals; Blood Glucose - analysis; BOVIN LAITIER; Butyrates - metabolism; Cattle - metabolism; COWS; DAIRY CATTLE; FATTY ACIDS; Fatty Acids, Nonesterified - blood; Female; FOIE; GANADO DE LECHE; GLUCOSA; GLUCOSE; Growth Hormone - administration & dosage; Growth Hormone - blood; Growth Hormone - pharmacology; HIGADO; HORMONAS PITUITARIAS; HORMONE HYPOPHYSAIRE; Hydroxybutyrates - blood; Insulin - blood; Lactation - drug effects; LIVER; Liver - analysis; Liver - drug effects; Liver - metabolism; METABOLISM; METABOLISME; METABOLISMO; MILK PRODUCTION; OXIDACION; OXIDATION; OXYDATION; Palmitates - metabolism; PITUITARY HORMONES; Pregnancy; PRODUCCION LECHERA; PRODUCTION LAITIERE; Prolactin - blood; Propionates - metabolism; VACA; VACHE
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(86)80460-X

Bovine growth hormone (50 IU/d) or placebo injections were administered for 11 consecutive d to Holstein cows (four per treatment) in midlactation. Growth hormone injections increased milk yield, efficiency of milk production, and concentrations of growth hormone and free fatty acids in plasma. Concentrations of beta-hydroxybutyrate and acetoacetate in whole blood and glucose in plasma were not affected by treatment. Liver biopsies were taken from both groups of cows 8 d prior to and on the last day of injection. Liver slices were used for in vitro incubations with carbon-14-labeled propionate, alanine, butyrate, and palmitate. Rates of substrate metabolism before and after placebo treatment were similar. Compared with pretreatment, however, liver slices from cows receiving growth hormone had significantly higher rates of propionate conversion to both glucose and carbon dioxide. There was also a nonsignificant increase in rate of alanine conversion to glucose and carbon dioxide. Growth hormone treatment did not change in vitro production of ketones or carbon dioxide from butyrate or palminate. Results indicate that growth hormone increases hepatic capacity for propionate metabolism and supports the concept that growth hormone partitions fatty acids for preferential use by mammary tissue.