Cereal grains represent 30 to 60% of the DM of many companion animal diets.
Once incorporated into a diet, the starch component of these grains can pr
ovide an excellent source of ME. However, crystallinity and form of starch
are variable and can cause incomplete digestion within the gastrointestinal
tract. Diets fed in this experiment included one of six high-starch flours
as the main source of carbohydrate. The flours originated from barley, cor
n, potato, rice, sorghum, and wheat. The diets were extruded and kibbled. S
tarch fraction concentrations of flours consisted of nearly 100% rapidly di
gestible starch (RDS) and slowly digestible starch (SDS) combined. Starch f
raction concentrations of diets paralleled concentrations in flours. Flours
varied widely in concentrations of CP, fat, starch, and total dietary fibe
r. Ileal OM and CP digestibilities were lowest for the potato flour treat-m
ent (74 and 64%, respectively). Ileal and total tract starch digestibilitie
s were different (P < .05) among treatments; however, the starch component
of all diets was nearly completely digested (> 99%). Total tract digestibil
ity of DM and OM was lowest for sorghum (80 and 84%, respectively) compared
to all other diets. Crude protein digestibility was highest for corn (87%)
. Wet fecal weights tended (P < .08) to be greatest for dogs fed the barley
treatment (175 g/d). However, dry fecal weights (dried at 55 degrees C) we
re greatest for dogs consuming the sorghum diet (51 g/ d). Fecal scares wer
e consistently greater (i.e., looser stools) for the barley treatment. Any
of these flours could be used without negative effects on digestion at eith
er the ileum or in the total tract. Fecal consistency data for dogs consumi
ng the barley treatment indicate that diets containing large amounts (> 50%
) of barley may not be advantageous for dog owners who house their animals
indoors for most of the day.