2016 ACVIM Forum Research Abstract Program

A prospective random two-way crossover study design was implemented using 4 healthy adult Angus steers previously fitted with duodenal cannulae located orad to the bile and pancreatic ducts. The steers were fed alfalfa hay ad-lib and whole corn and soybean hull meal pellets at 4 lbs/head 12 hours apart. On Day 1, steers were administered either 0.4 mg/kg famotidine or an equal volume of saline via jugular catheters. Whole blood and abomasal outflow samples were obtained at intervals for a 12-hour period. On Day 2, steers were administered either 0.4 mg/kg famotidine or saline IV at time 0, 8, and 16 hours. After a 24-hour washout period, the opposite treatments were administered and the study repeated. Whole blood and abomasal outflow samples were obtained at intervals for a 24-hour period. Abomasal outflow fluid was tested for pH using a commercial bench top pH meter within 5 minutes of sampling. Fluid pH was analysed using a mixed model in SAS 9.4 with treatment, sampling hour, and treatment*hour as fixed effects and steer and treatment period as random effects. Least square means were separated using least significant difference. Serum was separated and stored at À20°C until pharmacokinetic analysis. Serum famotidine analysis was performed using tandem liquid chromatography mass spectrometry and pharmacokinetic analysis was performed using commercial software.