Rehydrating scouring calves with an oral electrolyte solutions
Reviews by Nappert (1999) and Constable (2002) reveals a net loss of fluid, sodium, potassium, and chloride in scouring calves. Physiologically, scours is due to one of two main causative conditions, namely hypersecretion diarrhoea (marked by a severe watery diarrhoea and alkaline faecal pH), or malabsorption diarrhoea (marked by a malodorous diarrhoea and acidic faecal pH).
The type of scour depends on the type of pathogenic microbes involved. For example, Eschirichia coli is an enterotoxigenic pathogen that produces cholera-type toxins that stimulate secretion of fluids into the lumen of the abomasum and proximal small intestine, to the extent that the capacity of the large intestine to re-absorb the fluid is overwhelmed, and scouring is evident.
Other pathogens, notably Rotavirus, Coronavirus, and Cryptosporidia, are associated with tissue damage to the intestinal villi, thus causing malfunctioning of digestion and absorption in the small intestine. The increased load of nutrients in the digesta flow causes an increase in the osmotic pressure of the lumen contents, thus exacerbating fluid loss, with a net influx of fluid into the large intestine (normally the site where excess fluid is re-absorbed).
Dehydration is the inevitable consequence of such fluid loss, but is not the main cause of death in scouring calves. Rather, calves die of the physiological consequences of dehydration, namely disturbances in the acidbase and electrolyte balance of the body. Scouring calves become dehydrated, and suffer from metabolic acidosis (low blood pH), hyponatremia (too low sodium), and hyperkalemia (too high potassium), hypoglycaemia (low blood glucose), and a disturbance of the microbial balance of the small intestine (overgrowth of gram negative bacteria). Hence, the design of an effective electrolyte for treatment of calf scours needs to reverse all of these symptoms. Coetzee (2007) advocates a simple decision tool for route of rehydrant administration: if the calf can stand, offer oral rehydrant; if not, give the calf a drip (parenteral rehydration).
Meadow Feeds Electrolyte contains the physiological profile of nutrients and nutrient concentrations to achieve effective rehydration of scouring calves. Use it as an oral rehydrant by dissolving 90 g electrolyte powder in water (at body temperature: 39-40 degrees C) and make up to 2 litres. Feed scouring calves 4 litres of electrolyte solution per day. Coetzee (2007) recommends that the electrolyte solution be added as an extra meal, while still feeding milk. The milk should not be mixed with the oral electrolyte though, because there may be interference with abomasal clot formation. Although feeding milk to scouring calves may initially lead to more scouring, milk contains a lot of energy and amino acids, thus helping the scouring calf to regain a positive energy and protein balance during electrolyte treatment.
Date published: 2007-12-10