USE OF A BREATH TEST TO DETERMINE THE FATE OF SWALLOWED FLUIDS IN CATTLE

Objective-To investigate a [C-13]octanoic acid breath test as a means of detecting reticular groove contraction in cattle. Animals-19 adult dairy cows with fistulated rumen, 10 yearling bulls, and 6 yearling st eers. Procedure-Cows were given 200 mg of [C-13]octanoic acid in the c audal portion of the rumen, reticulum, or omasum/abomasum through the reticulo-omasal orifice, or were given the same dose of label with a d rench of water or sodium bicarbonate. Collected breath was analyzed fo r C-13 in CO2 for up to 3 hours. Breath of yearlings was analyzed for C-13 in CO2 over 20 minutes after drenching with 200 mg of [C-13]octan oic acid with water or sodium chloride and after sucking 200 mg of [C- 13]octanoic acid with molasses and water. Results-in cows, enrichment of C-13 in breath CO2 peaked at 20 to 30 minutes after placement of [C -13]octanoic acid through the orifice, compared with a lower peak at 6 0 and 90 minutes after placement in the reticulum and rumen, respectiv ely. The maximal increase in enrichment after placement of [C-13]octan oic acid in the reticulum did not overlap with the minimal increase wh en placed through the reticulo-omasal orifice. Enrichment values in co ws after drenching were consistent with values obtained after direct p lacement of [C-13]octanoic acid. in yearlings, the inclusion of sodium chloride in the drench greatly increased enrichment, compared with wa ter, but enrichment was greatest after sucking of the molasses, water, and [C-13]octanoic acid combination. Conclusions and Clinical Relevan ce-This breath test provides a simple, repeatable, nonradioactive, and noninvasive means of detecting the fate of swallowed fluids in cattle , thus revealing the route taken of orally administered therapeutic ag ents or nutrients.