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Management of calves in the presence of cryptosporidia

Tom Whitten Published on 20 November 2013

Over the last decade, we have seen an increase in calf scours caused by the protozoan parasite Cryptosporidium parvum. There are other species of cryptosporidium that infect calves but are of lesser importance.

Protozoans are a class of organisms that have only a single cell and include the organisms that cause coccidiosis in calves (Eimeria zuernii and Eimeria bovis). Unlike the eimeria parasites, cryptosporidium are very difficult to kill once they infect a calf.

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They also persist for a long time in the environment and resist almost all disinfectants and cleaners. While these organisms are present on a majority of farms regardless of the method of calf raising, the incidence can vary greatly.

The fewer calves that have the disease will result in less spread and decreased scours and sickness. There is no vaccine to prevent the disease, but some general recommendations can help reduce the incidence and severity of cryptosporidiosis.

Recommendations:

1. Have a good vaccination program in place to ensure adequate colostral immunity to respiratory and diarrhea diseases.

In general, it is cheaper to vaccinate the cows for scour control, but the oral products given to newborn calves can also have a place on the dairy. Work with your veterinarian to devise a program to optimize immunity in your calves.

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2. Make sure calves get a gallon of high-quality colostrum in the first six hours after birth. Pasteurizing colostrum is preferred, but no matter what method is used, the colostrum and milk or milk replacer should be cultured periodically for monitoring pathogen load of bacteria.

3. Calves should be placed in clean, dry calf hutches that are well-bedded with straw in the winter and inorganic bedding such as sand in hot weather. Hutches should be spaced 3 feet apart to avoid calf-calf infection.

4. All pails, bottles and nipple feeders should be thoroughly washed with detergent and allowed to dry between feedings.

5. The maternity area and dam are normally considered reservoirs of infection, which is one reason that diligent sanitation of the calving area and prompt separation of calf from the cow is so important.

6. It is generally recognized that the nutrient requirement of a diseased or chronically stressed animal is higher than normal, although no exact nutrient requirements have been established. This may be due to decreased absorption or increased demand for nutrients (or both).

I advise that calves not be removed from milk or replacer feedings for longer than two feedings. A partial feeding of milk may be of benefit, but if calves are off milk too long, they can starve.

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7. The feeding of a probiotic for the first two weeks of life may benefit calves raised in an environment where cryptosporidium are present.

It would seem that the probiotic bacteria colonize the gut before infectious agents like E. coli or cryptosporidium can have a negative effect. Some of these probiotics are combined with enzymes and vitamins that can aid nutrient absorption and support the immune system.

8. The latest treatment protocols address electrolyte balance, compensate for metabolic acidosis resulting from long-term fluid losses, address energy balance and partially address protein balance by incorporating milk or milk replacer feedings between electrolyte treatments.

There are big differences between commercially formulated electrolytes. Work with a knowledgeable veterinarian or nutritionist to decide on your choice.

9. Avoid the temptation to indiscriminately treat calves that have diarrhea with antibiotics. Antibiotics will kill the beneficial bacteria as well as any harmful bacteria. Use antibiotics judiciously and observe all withdrawal times.

10. In cold weather, consider the use of calf blankets to keep calves warmer and reduce stress and energy needs. Bedding with deep straw will help calves retain heat.

11. Calves should be allowed access to clean fresh water at all times, even if they have diarrhea.

12. While electrolyte therapy is the cornerstone of scours treatment, other ancillary measures can be of benefit. Such measures might include oral treatment with kaolin or pectin, B vitamins to maintain appetite and vitamins A, D and E for immune support.

13. In the last few years, there has been some interest in egg antibodies that specifically bind Cryptosporidium parvum. These antibodies are found in eggs of chickens injected with cryptosporidium oocysts.

These specific egg antibodies are called IgY or immunoglobulin Y (the Y stands for yolk) and can bind to the crypto and help remove them from the animal. Some research has shown these IgY antibodies can help aid in the reduction of cases of cryptosporidium.

Research has also seen some benefit when the IgY is combined with other ingredients that also can bind to crypto when fed to calves. Look for therapies that might include chicken egg proteins (IgY) as part of their formulations.

14. Do not bring calves from another farm onto your farm to replace a calf that died. This can serve as a way to bring new diseases into your herd.

One of the reasons infections with cryptosporidium have gained so much attention is due to their ubiquitous nature and the long duration of the diarrhea.

Cryptosporidium is primarily an oral-fecal spread pathogen, but it can also be aerosolized and inhaled. Some calves can re-infect themselves and the potential for transmission to farm workers is great (zoonotic potential).

To date, no approved treatment exists for cryptosporidium but some avenues of research, such as the chicken egg IgY approach in combination with other binding agents, do show promise in prevention and treatment.

As always work closely with your veterinarian or health adviser to develop a sound program to prevent diarrheal diseases. PD

00_whitten_tom

Tom Whitten
Veterinarian

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