Six Holstein steers were used to evaluate the effects of increasing ruminal butyrate on
net nutrient production and absorption by the gastrointestinal tract and liver. Ruminal and
arterial concentrations and net hepatic flux of butyrate increased with increasing butyrate
infusion. Concentrations of glucose and a-amino-N in arterial blood decreased as butyrate
infusion increased. Of the ruminal butyrate infused, 24.5% appeared in portal blood as
butyrate. Acetoacetate, D-β-hydroxybutyrate, and a-amino-N were the nutrients most altered by
increasing ruminal butyrate.
