Metabolic responses of lactating goats to feed restriction and dietary 1,3-butanediol

Feed restriction and dietary 1,3-butanediol were used with lactating goats in an attempt to induce metabolic changes characteristic of bovine lactation ketosis and fatty liver. In Experiment 1, midlactation goats were fed 80, 102, or 114% of metabolizable energy requirements and 0, 50, or 100 g/d of 1,3-butanediol. Concentration of beta-hydroxybutyrate in blood plasma decreased with increasing metabolizable energy but was increased greatly at 2 h after goats were fed 50 or 100 g butanediol and remained elevated at 6 h postfeeding with 100 g of butanediol. Concentration of glucose in plasma was decreased at 2 and 6 h postfeeding in goats fed 100 g of butanediol. In Experiment 2, goats in early lactation were fed for ad libitum intake or were restricted to 70% of ad libitum intake with 1,3-butanediol included at 10% of diet DM. The treatment decreased milk production, increased concentrations of beta-hydroxybutyrate and nonesterified fatty acids, and decreased the concentration of insulin and the insulin to glucagon ratio in plasma. Concentrations of glucose, acetate, and glucagon in plasma were not affected. After 28 d of treatment, concentration of total lipid in liver was increased, but concentrations of glycogen and triglyceride were unaffected. Changes caused in goats by feed restriction plus dietary 1,3-butanediol were characteristic of subclinical lactation ketosis in cows, but the response was more moderate than seen previously in cows.