Detrimental effects on villus form during conventional oralrehydration therapy for diarrhoea in calves; alleviation by a nutrient oral rehydration solution containing glutamine

This paper examines the possibility that treatment of diarrhoea with conventional oral rehydration solutions (ORSs) may be detrimental to villus structure by imposing nutrient deprivation and that such detrimental effects may be reduced or avoided by using a nutrient ORS. A conventional WHO-type ORS (W) was compared with two nutrient solutions (N and G) both containing high glucose concentrations and the latter containing glutamine; their effects on enteric structure were assessed by morphometric analysis of samples obtained from diarrhoeic calves after 96h treatment. Comparisons were also made with samples from controls and diarrhoeic calves at the stage where oral rehydration would have begun in the treated groups. As in our previous ORS studies, diarrhoea was induced with enterotoxigenic Escherichia coli (09:K30:K99). We measured villus length and width, crypt depth and width and calculated villus surface area in proximal, mid and distal small intestine (PSI, MSI, DSI), using standard morphometric techniques. Proximal and distal spiral colon samples (PC, DC) were examined for crypt depth and width; mitoses per crypt were counted in samples from all regions. Non-diarrhoeic calves showed the expected gradient of villus length through PSI, MSI and DSI, hence data for each region are normalized as a percentage of the control value for that region. PSI showed the greatest loss of villus length and surface area (50%) with diarrhoea. In MSI and DSI the villus loss was greater with solution W and N or G, as were increased mitoses and crypt depth. Crypt depth and mitoses also increased in the colon with solution W. Colonic crypt width increased with diarrhoea and conventional oral rehydration but less so with G; there is reason to believe that such changes have functional significance. Crypt changes in colon, MSI and DSI were least with solution G. The changes developing in diarrhoeic calves prior to treatment were thus less apparent in those treated with a nutritional ORS, particularly if it contained glutamine.     

Sodium in health and disease: a comparative review with emphasis on herbivores

This review aims to illustrate the relationships between a number of basic and clinical aspects of sodium metabolism with special emphasis on herbivores, particularly ruminants. These animals provide a challenge to some traditional views based essentially on humans, dogs and laboratory rats reared on liberal sodium intakes. Detailed attention is focussed on two central issues; the magnitude of sodium requirement and the relative importance of the kidney and the gut in regulating body sodium. Both provide strong reasons to question accepted beliefs.     

Student selection: time to reconsider?

The fate of most aspiring veterinary surgeons is determined not by their professional examinations but by their A-level results. Anything less than two As and a B and the outlook is bleak, though not irretrievable. In this article, Dr Robert Michell examines the system by which students are selected, and suggests that the system is ripe for re-evaluation.     

Epidemiological studies of pig diseases: 1. Use of French protocols for risk factor assessment to predict the health status of Australian herds

Objective To determine in Australian pig herds the accuracy of French protocols for risk factor assessment.
Procedure Data on health indicators and risk factors were collected for three syndromes, 'pre-weaning diarrhoea', 'post-weaning diarrhoea' and 'respiratory problems', using the French protocols. The protocols were used on 118 occasions in 32 Western Australian pig herds during 3 years (1988 to 1991).
Results There was a wide variation in pre-weaning performance, for example growth rate was 107 to 273 g/day (< 200 g/day in 33% of herds). Respiratory lesions at weaning were associated with poor pre-weaning performance. Post-weaning (21 days after weaning) growth rate was 114 to 408 g/day (< 250 g/day in 54% of herds). In the grower herds, 91% of herds had pneumonia, and growth rate was 439 to 625 g/day (< 550 g/day in 54% of herds). Pleurisy as well as pneumonia was associated with reduced growth rate. The risk factor most closely associated with respiratory health status was air volume per pig.
Conclusion Risk factors were most accurate at predicting the health status in post-weaning problems. A weaning weight of at least 7.9 kg and weaning age of 30 days optimised weaner performance. Stocking densities and shed designs providing at least 3 m³ air volume and 0.6 m² floor space per pig throughout the growing phase should be considered for an improved respiratory health status. Australian pig sheds often do not provide a satisfactory environment for optimum health. The technique of risk factor assessment as an aid to the maintenance of health in pig herds is applicable in Australia, but further research is necessary to determine the most important Australian risk factors.     

Effect of oestrogen and progesterone on sodium, potassium and water balance in sheep

The effects of oestrogen and progesterone, injected alone or during successive periods, were studied in mature ovariectomised ewes on sodium intakes ranging from 1 to 4 mmol kg-1 d-1. Progesterone had no effect on fluid and electrolyte balance. Oestrogen (17 beta oestradiol) inhibited drinking but had little effect on water excretion whereas it reduced both food intake and urinary potassium concentration. Since the resulting changes in potassium intake and excretion were very similar, oestrogen had little net effect on potassium balance; neither change lasted beyond the treatment period. Oestrogen had a biphasic effect on urinary and faecal sodium excretion, an initial enhancement of salt loss being followed by sodium retention. Faecal sodium retention and the biphasic effect on renal sodium excretion were independent of changes in food intake. These observations are discussed in relation to the pattern of change of electrolyte balance during the reproductive cycle and the influence of changes in food intake and factors affecting sodium preference. The fact that a variety of responses is involved in a coordinated change of sodium balance is emphasised and its possible importance is considered.