BLOOD BUFFERING IN SEDENTARY MINIATURE HORSES AFTER ADMINISTRATION OFSODIUM-BICARBONATE IN SINGLE DOSES OF VARYING AMOUNTS

Blood acid-base and electrolyte status was studied in four sedentary M iniature Horses treated with 200,300,400 and 500 mg of sodium bicarbon ate (NaHCO3) Per kg of body weight (BW). Arterial blood was collected before treatment with NaHC03 and each hour for 5 h after treatment. Al l treatments resulted in an increase in blood pH, bicarbonate (HCO3-) concentration and base excess (BE) by 1 h post-dosage, which continued through the 5th hour (P < .05). Treatment with 200 mg NaHCO3/kg BW re sulted in less elevated blood HCO3- concentrations (P < .03) and BE va lues (P < .01) when compared to the other treatments. Following dosing with NaHCO3, plasma Na+ concentrations increased among all treatments but declined to initial values by 3 h post-treatment. The 200 mg NaHC O3/kg BW dosage resulted in the smallest increases in plasma Na+ conce ntrations (P < .03). Both plasma K+ and Ca++ concentrations were lower (P < .05) among all treatment groups 1 h post-dosage but returned to initial values by 5 h and 3 h posttreatment, respectively, with no dif ferences (P > .05) among treatments. All NaHCO3 dosages increased bloo d buffering capacity as indicated by increased blood pH, HCO3- concent ration and BE. Maximum blood pH, HCO3- concentration and BE was reache d using a dosage of 300 mg NaHCO3/kg BW. Also, all treatments altered the plasma electrolyte concentrations.