Intravenous infusion of glucose and insulin in relation to milk secretion in the sow.

1. A comparison was made of the composition of milk from front and rear tetas in four sows. There were small and not significant differences in fat, protein and lactose contents, and in the fatty-acid composition of the milk fat with the exception of the 18:3 acid where the difference was also small but significant. 2. The effects of intravenous infusions of glucose and insulin in lactating sows on milk secretion and blood composition were investigated in two sows. 3. Intravenous infusion of glucose had no effect on blood plasma glucose concentration but increased the yields of lactose, protein and water. 4. Intravenous infusion of insulin depressed plasma glucose concentration and the yields of lactose and water. The yield of protein was unaffected. 5. It is concluded that differences between the non-ruminant (the sow) and the ruminant in the responses in milk secretion to glucose infusion may be related to differences in the sensitivity to insulin of mammary tissue.