INDUCED DIARRHEA IN HORSES PART-1 - FLUID AND ELECTROLYTE BALANCE

Sodium, potassium and water balance, and measurements of acid-base sta tus, haematocrit, packed cell volume and plasma total protein, were st udied in four adult standardbred geldings following castor oil induced diarrhoea. Castor oil (2 mL kg(-1)) administration resulted in signs consistent with mild to moderate acute colitis. The total (combined fa ecal and urinary losses) losses of sodium and potassium ions were 2169 and 2864 mmol, respectively. Faeces constituted the major route for s odium loss, while urine was the major route for potassium loss at all times. Faecal dr): matter potassium concentration did not vary signifi cantly at any stage. Faecal dry matter sodium concentration increased significantly, coinciding with the onset of clinical diarrhoea. Faecal water loss increased significantly from 2.15+/-0.44 mL kg(-1) h(-1) t o 5.15+/-0.92 mL kg(-1) h(-1) while clinical diarrhoea was observed. W hile plasma volume (PV) did not vary significantly in this study, ther e was a trend for PV to decrease while horses were clinically dehydrat ed.