The Importance of Glucose Supply at the Initiation of Artificial Lactation in the Ewe

Abstract

Ewes induced to lactate artificially were given continuous intravenous infusions of either saline or glucose in saline during the first 5 days of lactation. Glucose-infused ewes secreted significantly greater (P < 0·05) amounts of milk than control ewes during the first 10 days of lactation. On the tenth day of lactation glucose-infused ewes secreted approximately twice as much milk as control ewes (c. 320 v. 160 g/day). Plasma concentrations of glucose and insulin were significantly higher (P < O· 05) on the first 2 days of lactation for glucose-infused than control ewes.The results suggest that glucose supply to the mammary gland at lactogenesis may be rate-limiting for milk production during early lactation.

Glucose Turnover and Hepatocyte Glucose Production of Starved and Toxaemic Pregnant Sheep

“…The constraint is lifted after parturition when much higher rates of glucose production are needed to support milk production (Bergman 1973). Support for this hypothesis is that the poor rates of milk production seen after the artificial induction of lactation (Gow et al 1981) can be increased by an intravenous glucose infusion of 0·22 mmoljmin (Leenanuruksa and McDowell 1982). We therefore suggest that, during pregnancy, the liver is prepared for high rates of glucose production during lactation but its manifestation is somehow constrained by the presence of a live foetus.…”