Intravenous solutions for fluid therapy in calf diarrhoea

Five commercially available parenteral solutions were compared for their effectiveness in correcting the disturbances associated with diarrhoea induced by Escherichia coli. Each solution (saline, Hartmann's, Darrow's, Plasmalyte +/- glucose) was tested on eight Jersey calves less than a week old and weighing approximately 25 kg. Each calf received 8.5 litres over three days, at about 20 ml kg-1 h-1. Solutions such as saline or Plasmalyte which had higher concentrations of sodium were more effective at correcting dehydration and electrolyte disturbances than those with less sodium (Darrow's, Hartmann's) but only those with bicarbonate precursors (lactate, acetate, gluconate) were effective in correcting metabolic acidosis. The additional potassium in Darrow's was predictably unhelpful in correcting hyperkalaemia and the additional glucose in Plasmalyte-glucose, despite some beneficial effects, undermined its effectiveness in correcting acidosis. These results suggest that solutions for intravenous treatment should probably contain about 150 mmol litre-1 Na+, 5 mmol litre-1 K+ and about 50 mmol litre-1 of a mixture of bicarbonate and precursors. Neither of the commonly used solutions (saline or Hartmann's) is thus ideal.