Gerald Hauer, DVM
Bison Production Specialist
Alberta Agriculture, Food and Rural Development
Bison Centre of Excellence, Leduc, Alberta.
Phone: (780) 986-4100
Reprinted from The Tracker, volume4, issue 3, March 2000
Neonatal diarrhea (calf scours) can be a devastating disease in many types of farm animals if they are not managed properly. Bison calves may be affected if they are exposed to the conditions that are favourable for the disease to occur. Learning how to control these conditions is the key to prevention.
Calf scours (neonatal diarrhea) has plagued beef and dairy farmers for years and is now affecting some bison and elk producers as well. It is frustrating to deal with and can be devastating to the newborn calves. A little understanding of the disease can help prevent it from occurring in your herd and save you a lot of headache in the end.
Calf scours is caused by many different agents. Some of these agents are considered primary pathogens and have the ability to cause diarrhea all by themselves. E. coli bacteria, rota and corona viruses, and coccidia are examples of primary pathogens. Other agents such as Cryptospoidia and Giardia don’t cause much of a problem on their own but have the ability to make scours much worse if the calf is already infected with a primary pathogen. In these cases the diarrhea is more severe, lasts longer, and is more difficult to treat than if only one agent is causing the problem.
The pathogens generally survive in the adults and are shed in the feces in low numbers which serves as a source for infection for the newborn. The organisms are ingested and then colonize the lining of the intestines of the newborn calf. The organisms cause diarrhea in a number of ways. One method is to stick to the intestinal wall and produce a toxin that causes the intestinal cells to secrete copious amounts of fluid into the intestines. Another method is to attack and destroy the intestinal cells which causes fluids from the calf’s tissues and blood stream to pour into the intestine. Often there is a mixed infection of pathogens and more than one process occurring at the same time.
Illness and death occurs in calves due to a number of events that take place in the calf’s body. Dehydration occurs due to the loss of fluids in the diarrhea. Electrolyte imbalance and acidosis (lowering of the bloods pH) occurs due to the loss of electrolytes in the diarrhea. Secondary bacterial infections are common because the damaged intestinal lining can’t keep bacteria from entering the blood stream from the inside of the intestines. All three events can occur at one time and can make the calf very ill in a short time.
Treatment is aimed at preventing death cause