Equids are obligate hindgut fermenters and thus are equipped with a large cecum and voluminous proximal colon for microbial fermentation of plant cell wall fiber components. Suids are also hindgut fermenters; however, because they have evolved consuming highly diverse diets, they are also classified as omnivores. Suids share similar gastrointestinal anatomical features with equids, and therefore may be a useful model of gastrointestinal nitrogen and carbohydrate metabolism. Important differences exist in the kinetics of glucose transport between equine and porcine small and large intestinal tissues, and these differences shed light on the divergent ability of these 2 species to absorb dietary carbohydrates. In contrast, the 2 species share distinct similarities in intestinal Lys transport kinetics. In both species, the large colon apical membrane is capable of Lys transport via a high capacity and lower affinity transport process that is higher than that of the small intestine. Lys transport across the pig and the pony jejunum is 1.14 and 1.16 $\rho#$moL/mg tissue (V_max), respectively, and uptake by the pig and pony colon is 0.84 and 0.91 $\rho#$moL/ mg tissue (V_max), respectively. In both species, the large colon has a lower affinity for Lys compared with the small intestine (i.e., 0.89 and 1.05 K_M, pig and pony, respectively). The broader capacity of Lys transport in the large colon is indicative of the potential role it plays in the uptake of Lys. It is proposed that the porcine model may be useful to predict amino acid requirements for maintenance and digestibility in equids.