Annual losses to the beef industry from neonatal scours runs into the tens of millions of dollars. The losses come not only from calf mortality and treatment costs, but also from lost performance in the surviving calves.
The cause of scours ranges from infectious viral, bacterial and protozoan origins to nutritional imbalances and toxin consumption. The most important scours control factor is to ensure that calves receive an adequate amount of high-quality colostrum. This can't be stated enough.
In the first few weeks of its life, a calf's ability to react to stress isn't fully developed. It can't maintain body temperature as well as an adult or older calf. Wet conditions and wind are the two most severe weather stressors. A dry, comfortable, warm place for calves to rest, along with frequent nursing, are the main needs of a newborn calf.
The basic treatment of scours should be supportive therapy. This includes electrolytes, dextrose or glycine, probiotics and an alkalizing agent along with antibiotics as needed for secondary infections that may occur.
A common treatment has been to remove the calf from its milk source — whether that's the cow or a bottle — and give it only electrolytes. Electrolytes were designed to rehydrate the calf, reduce blood acidosis, provide some energy and restore chemical balance in the calf's metabolic system. They were never intended as a complete nutrient source.
The calf may survive a few days on only electrolytes and what little body fat it may have, but the calf needs an energy source along with a source of protein, minerals and vitamins for its metabolism. However, if the calf has not nursed for several days, then high-energy rehydration solutions are necessary for calf survival.
The best remedy for calf scours, however, is prevention. That means good pre-calving nutrition.
In one study, cows producing calves that died from scours had colostrum with lower levels of vitamins A and E, copper and zinc. Another study showed that calves with scours caused by E. coli had lower system concentrations of copper, zinc, magnesium and vitamin A.
We know that vitamin A is critical to maintaining a healthy surface lining of the bowel. Therefore, it stands to reason that vitamin A is important in calf scours. Stress and disease both increase the requirement for vitamin A.
It's also been shown that in some cases, oral vitamin E and selenium will reduce the occurrence of scours.
The one area of calf scour treatment that is grossly neglected is the resulting acidosis in scouring calves. Fecal losses of bicarbonate, as well as decreased blood flow and volume from dehydration, increases the production of lactic acid in diarrhetic calves. This limits the kidneys' ability to excrete waste products.
Scour therapy should include an alkalizing agent to buffer the system. Non-correcting of this acidosis may explain many death losses in scouring calves.
The main objectives of oral rehydration should address the following:
restoration of fluid volume,
replacement of lost electrolytes, especially sodium and potassium,
correction of acid-base imbalance and
maintenance of energy levels throughout the treatment period.
Restoring the fluid volume should be the first priority in treating calf scours. With increased fluids, blood pressure rises, enabling the calf to stabilize circulatory balance and also helping to maintain acid-base balance.
Typical therapy for a mildly dehydrated calf is about 2 qts. of fluid/dose. This needs to be repeated every five to six hours as the calf will lose another 5% of fluid in this time. We often mistakenly think that one treatment will take care of the problem. Generally, the calf needs about 10% of body weight or 1 gal. for an 80 lb. calf each day of treatment. Severely dehydrated calves will require more fluids.
Replacing lost electrolytes and adjusting pH is also necessary along with supplying some energy needs. These may be accomplished with the oral administration of a high-quality electrolyte solution.
The electrolyte solutions used should contain electrolytes, especially sodium, potassium, chloride and bicarbonate, and an energy source. Probiotics also may be beneficial, but this is controversial at this time.
The goal of rehydration is to keep the calf alive and functioning so that it may heal the gut. Just stopping the diarrhea may not be the cure.
David Wieland is a nutrition consultant specializing in cow/calf, feedlot and horses. Based in Shepherd, MT, he also publishes a subscription newsletter. Contact him at 406/373-5512 or [email protected].