Effects of abomasal wheat starch infusion on splanchnic metabolism and energy balance of lactating dairy cows

In lactating dairy cows infused abomasally with 1200 g wheat starch per d for 8 days the recovery of wheat starch, as increased net glucose absorption was 39%, whilst the recovery las increased liver glucose production) of starch infused into the rumen, was 26%. Starch infusion into either site decreased ammonia absorption, which probably reflects an increase in N use for rumen or hindgut fermentation. In separate cows, 14 day abomasal starch infusions decreased N digestion but tended to increase tissue N retention. Of the starch energy infused, 59% was recovered as metabolizable energy (ME), whilst 74% of the increased ME was retained as tissue energy.