FALLIBILITY OF FECAL CONSISTENCY AS A CRITERION OF SUCCESS IN THE EVALUATION OF ORAL FLUID THERAPY FOR CALF DIARRHEA

It is often said that tile success of oral rehydration in humans depen ds on the adequacy of the improvement in tile composition and volume o f extracellular fluid, not reduction of faecal output. Indeed, the lat ter may increase initially. Such increases do not prevent tile treatme nt from being effective but they may, falsely, undermine its acceptabi lity to patients or those caring for them. This paper provides data to show that standard oral rehydration solutions used to treat experimen tally induced calf diarrhoea procure identical improvements in plasma volume during the first 48 h, whether faeces improve or not, and those cah es whose faecal consistency improved actually showed greater dete rioration of extracellular fluid volume. While it is important for thi s to be appreciated by clinicians and explained to owners, it is absol utely imperative that those responsible for the approval of new therap eutic products for registration understand and accept that faecal cons istency offers no reliable insight into the effectiveness of oral rehy dration therapy for calf diarrhoea. It was, however, interesting that there was some relationship with correction of acidosis-perhaps becaus e some of the contributing factors arise from colonic dysfunction.