Calf Scours - Rota/Corona/Crypto/E.coli

The majority of death losses from calf-hood diseases are caused by diarrheal and respiratory pathogens. While vaccination targets protection against specific pathogens, adequate consumption of high quality colostrum will provide broad-spectrum protection against most diseases prevalent on a dairy farm.


Colibacillosis - E. coli - Colibacillosis usually occurs in calves 1-10 days old. Typically, calves out of first calf heifers are more susceptible. Other associated factors include seasonal variation, overcrowding and poor sanitation which allow build up of organisms in calving pens. Milk pails and feeding equipment can become contaminated. Signs include frequent and effortless diarrhea, pasted rear quarters, fluid or semisolid malodorous feces with chunks of partially digested milk, rapid dehydration and weight loss, depression, anorexia, weakness, and death. Body temperature is normal at first but subnormal as the disease worsens. Death can occur in 3-5 days. Mixed infections can occur along with rota/corona virus and/or cryptosporidiosis. Illness can occur in up to 75 percent of calves on a farm, while death losses can range from 10 to 50 percent in unvaccinated herds.

Rota virus - Rota virus infections affects calves between 1 and 21 days old. The disease is characterized by sudden onset and rapid spread. Calves become reluctant to stand and nurse, mildly depressed, salivate, and have watery, yellow diarrhea. The diarrhea lasts 1-2 days and maybe longer with secondary infection (3-5 days). Under germ-free conditions rota virus infections are self-limiting and of short duration 6-10 hours (like the 24 hour flu). Serum antibodies do not protect calves from infection. As the level of colostral antibodies present in the intestines decline, calves become more susceptible.

Corona virus - Corona virus infections are similar to rota viral infections except, usually the clinical signs are more severe. Calves up to 3 weeks old can be affected. Clinical signs include sudden onset of diarrhea, moderate depression, reluctance to nurse, passage of feces containing mucus and milk curds. After 2-4 days of diarrhea, calves become severely depressed, weak, gaunt, and eventually die. Under germ-free conditions corona virus is more severe and can lead to death. Typically, corona virus is found along with other diarrheal disease agents.

Cryptosporidiosis - Transmission of cryptosporidia is by fecal-oral route. Within the intestines auto-infection can occur in immuno-suppressed calves. The entire developmental cycle can occur within 72 hours. Natural infection occurs in calves 1-3 weeks of age. Clinical signs include increased frequency of defecation, straining, anorexia, weight loss, depression, and dehydration. Diarrhea is profuse, watery, and has a yellow color. Usually many calves are affected but few die as a direct consequence of cryptosporidiosis. There appears to be a seasonal effect with more disease occurring during fall/winter or stressful periods. Affected calves need supportive care since the disease is self-limiting and the intestinal repair can be prolonged. Cryptosporidia oocysts are difficult to detect. Routine fecal tests will not find the organism. A special acid-fast stain is required to diagnose cryptosporidiosis. Oocysts do not survive freezing or temperatures above 150o F for 30 minutes, but will survive at 40o F in liquid slurries. Bleach nor alcohol are effective at killing the oocysts. Strong Lysol (5% solution available from hardware stores) can be used to disinfect contaminated surfaces. Cryptosporidiosis is a public health hazard! In humans, clinical signs include abdominal cramps, vomiting, diarrhea, and fever (flu-like symptoms).

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