The Bagpipe - American Highland Cattle Association

species. Another vaccine is given orally to the calf at least one hour before it has consumed any colostrum, as
colostrum will neutralize the attenuated virus used in the vaccine. This method of prevention requires meticulous
diligence to management of newborn calves.
Coronavirus diarrhea: This virus causes a severe and long-lasting disease with a high morbidity (the number of
calves affected) and moderate mortality (the number of calves that will die). Fortunately this virus appears to be less
widespread than rotavirus. The calves are commonly affected between 5 and 21 days of age but when the virus is first
introduced into the herd, calves up to 6 weeks may be affected. Depression is not as severe as that seen in rotavirus
infection. Diarrhea and dehydration progress though a course of 4-5 days with the calf becoming moribund. Severe,
watery diarrhea is not a feature of this disease, although mild respiratory signs may be seen if the virus is present
in the air and inhaled. Diagnosis depends upon laboratory methods.
There are several vaccines available against coronavirus including one given to pregnant cows in combination
with rotavirus and ETEC. Likewise, an oral vaccine given prior to colostral intake by the calf is also available.
Efficacy of both is questionable.
Importantly, there may be a synergism between coronavirus and prepatent (before maturation) coccidia infection.
This may explain the severity of the illness attributed to coronavirus alone. If this is truly the case, then anticoccidial
treatment may become a significant method of controlling morbidity and mortality of coronavirus infection.
Coccidiosis: This disease is caused by protozoa, single-celled organisms that invade the intestinal tract of animals.
Only certain strains cause disease in cattle. This organism causes disease in calves usually older than 3 weeks of age
and often occurs 7-14 days after being moved from calving lots onto pasture. Coccidiosis is often considered a disease
of intensive animal husbandry and overcrowded conditions but free ranging animals are also at risk. Older cattle are
carriers of coccidia and typically contaminate pastures. The organism is resistant to disinfectants and can remain
viable in moist shady areas for years. However, sunlight, freezing temperatures and desiccation will destroy the
oocysts. Severity of disease varies with the number of oocysts ingested. If the calf is exposed to just a few, it may
develop immunity and never show any signs of disease. Moderate numbers may induce mild disease before complete
immunity is reached. Ingestion of large numbers of oocysts usually results in severe disease and occasionally death.
Signs include bloody diarrhea, rectal straining and discomfort, loss of appetite, slight fever and debility. A typical sign
of coccidia is finding calves with diarrhea smeared across their rumps as far as their tail will reach. Diagnosis is
based on clinical signs and finding oocysts during microscopic examination of manure. Treatment of disease consists
of using amprolium (Corid) or a sulfonamide. Other medications are used prophylactically as a preventative for
coccidiosis and are not suitable for treatment of acute disease.
Cryptosporidiosis: Cryptosporidium parvum is a protozoal coccidian parasite and is a very important zoonosis
(disease that affects both animals and humans). Four hundred thousand people contracted this disease when oocysts
(eggs) contaminated the Milwaukee water supply. Infections can easily spread from calves to humans. Persistent and
fatal diarrhea can affect both calves and humans.
Signs of the disease are nonspecific and vary from depressed appetite with mild diarrhea to protracted, watery
diarrhea and debilitation. The diarrhea is nonresponsive to medication as this organism is resistant to conventional
antimicrobials, including those routinely used for treating coccidia. This usually affects 1-3 week old calves.
Dehydration may not be a factor but weight loss leading to emaciation is virtually certain. The diarrhea may last 6-
10 days, with maximum oocyte detection occurring at 12 days of age. This is the ideal age to sample calves to detect
the presence of C. parvum as this can be a difficult pathogen to find. The organism is destroyed by freezing but is
extremely resistant to disinfectants.
Unfortunately at this date, there are no practical treatments for C. parvum. Paromomycin and azithromycin
(Zithromax) are used in human cases but are prohibitively expensive. Lasolocid (Bovatec) does help prevent infection
but at doses so high they could cause death in 50% of the calves treated.
Clostridium perfringens type C enterotoxemia: This disease is caused by the toxin produced by a ubiquitous
organism commonly found in the gut of many mammals including cattle. Disease occurs when the organism
proliferates and produces one or more toxins. This is usually seen in calves less than 2 weeks old. Death may occur
so rapidly that signs of abdominal pain and depression are never even noticed. Diarrhea, if it is seen, would be
profusely hemorrhagic, many times looking like pure blood. Diagnosis is usually made at autopsy, the presence of
extensive hemorrhage in the small intestine (purple gut) is highly suggestive. Treatment is extremely difficult due to
the rapid onset and course, with a poor prognosis regardless of signs. Hyperimmune serum, massive extra label doses
of penicillin intravenously, rapid IV fluid therapy and anti-inflammatories to combat endotoxic shock may be
successful if started early enough.
Prevention is vaccination of the cow with the appropriate clostridial toxoid two times and then on a yearly basis.
The calf, of course, must consume adequate colostrum.
Salmonellosis: This disease probably gets more attention because it is associated with illness in humans. There are
over 1000 types of salmonella; virtually all can cause disease. In cattle, it is capable of causing high rates of disease
in both calves and adults. This organism produces a potent endotoxin within its own cells. When the organism is
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