Don’t Fall Behind with Coccidiosis

Among the “biggies” of pathogens that cause scours in both pre- and post-weaned calves is coccidia, a parasitic protozoa that sets up shop in the intestinal tract of cattle. Eggs are produced internally and pass into the environment via shedding in manure.

Shedding of coccidia “eggs” or oocysts by infected calves and heifers usually peaks about 3 weeks after initial exposure. In one study the peak numbers of oocysts shed per day by untreated infected calves was 50,000,000 on day 21! Older, immune animals continue to contaminate their environment at a much lower — but consistent — rate. These facts tell us that from the moment a calf is born, she is very likely to get some of these oocysts in her mouth.

Don’t fall behind – reduce exposure of newborn and older calves

Once a newborn calf stands up, she is in a perfect situation to begin getting coccidia eggs in her mouth. Licking the dam’s hair coat, searching for a teat to suck, and licking on anything in her environment, unfortunately, all are generous sources of coccidia eggs. Moving her to a cleaner space does work to cut exposure.

Among older calves, we should think about ways to reduce their shedding rates (that is, the rate that she passes coccidia eggs in her feces):

  • Create clean, well-bedded resting space for calves.
  • Optimize ventilation in the barn and calf or heifer pens.
  • Provide adequate feed space per animal.
  • Minimize weight and age variation between animals in the group.
  • Avoid feeding on the ground unless it is at a bunk.
  • Provide 12″ of linear water space per 10 animals.
  • Treat infected animals.
  • Maximize time between successive occupants of the same pen.

Managing infections – building immunity

On nearly all dairies, all animals will eventually be exposed to coccidia. Through natural exposure, they will build immunity that suppresses infection. If the exposure of young calves can be managed to maintain a low level of infection, they can build immunity without excessive damage to their gut and loss of normal growth.

So, what can we do if natural exposure rates are uncontrolled (and likely to be high)? Use one of the feed additives that act to control coccidia activity in the calf after exposure. The four additives approved for use in the United States include:

  • Deccox®-M [decoquinate] – available in milk replacer, or powder, mixed with milk to make suspension
  • Bovatec® [lasalocid] – available in milk replacer, liquid additive to mix with milk
  • Rumensin® [monensin] – added to dry feeds like calf starter grain
  • Corid® [amprolium] – liquid can be added to milk or milk replacer, or dry crumble

When used as prescribed, all of these additives limit the population of coccidia in the gut. Their effectiveness is shown in studies in which the shedding rates have been reduced about 96 to 98 percent.

Preclinical use of the additives is recommended. Damage in the gut due to uncontrolled growth of coccidia will occur as early as 5 days after coccidia exposure. Thus, don’t wait until clinical symptoms are present to begin using the additive that you and your veterinarian believe is best for your situation.

What You Can’t Do With a VFD

For some time now, livestock producers and veterinarians have been gaining an understanding of the new Veterinary Feed Directive (VFD) rules. These rules went into effect on January 1, 2017, and as the year progressed, livestock producers have been confronting what those rule changes mean for their own operations. Before January 1, feed-grade antibiotics such as chlortetracycline (CTC) for their animals could be purchased and used by livestock producers without any input from a veterinarian. Now, in order to use those medications, a VFD form from a veterinarian must be obtained.

Understanding the New Rules

As all parties have quickly discovered, the VFD process is more than just having a vet’s signature on a scrap of paper. Because there is no allowance for using feed-grade medications in an “off-label” manner, veterinarians completing the VFD’s have had to pay exquisite attention to every detail on the label, including the dose, duration of feeding, reasons (disease treatment vs. control) for feeding, and the diseases the medication could be used for.

For many cattle producers, the fall of 2017 has been the first time they’ve encountered this new way of doing business. Issues with pneumonia post-weaning, or following arrival of feeder cattle have always been challenges. In past years, uses of CTC in cattle feed have been subject to very little oversight, and some of those uses, although well-intended, were off-label. With the onset of the new rules, producers are having to square their previous treatment methods with what a VFD can – or can’t – allow them to do.

  • Refills
    A VFD can’t provide for refills, like a prescription one might get from a family doctor. This means a producer can’t use the same VFD form to come back and get another quantity of medicine if it’s determined to be needed later on.
  • Expiration Dates
    All VFD’s have expiration dates, and that’s a point of confusion as well. A VFD actually expires when the treatment is done (or the expiration date is reached – whatever comes first). Even though a VFD might not expire until February (authorizing a treatment any time until then), if a 5-day treatment is finished in November, the VFD is finished too.
  • Repeat Treatments
    A VFD can’t contain a statement authorizing a “retreatment as needed” or “repeat treatment in xx days.” An animal can’t show up on a VFD form more than once. If another round of treatment is necessary, a veterinarian will have to issue another VFD for the second treatment. That means that some groups of cattle might need 2 or 3 separate VFD’s written for them.
  • Animals Covered
    A VFD can’t be written for more animals than the veterinarian expects you’ll have on the farm. The veterinarian is responsible for indicating the number and location of the animals to be treated. This might get a little tricky for producers who buy several groups of feeder calves over time. Veterinarians might decide to only write the VFD for what is currently on the farm, or they could write it for the number eventually expected, if they are confident that number will be eventually procured.
  • Pneumonia 
    A VFD can’t be written to treat or control pneumonia when there isn’t any pneumonia in the cattle. In the past, it was not uncommon for treatment doses of CTC to be fed to cattle to “get ahead of” an outbreak, or to “clean up” the calves’ respiratory tract in anticipation of problems. When treatment doses are authorized by a VFD, this implies that active pneumonia is present in the group. It doesn’t mean producers have to wait until each and every calf is sick – but clearly, CTC labels don’t allow for using treatment doses in a group of completely healthy calves. This is the veterinarian’s call. If their clinical judgement tells them there’s pneumonia present in the group, they can write the VFD.

In Summary

It’s understandable that some livestock producers are feeling pinched by what a VFD can’t do. However, these new rules can do one very valuable thing: giving livestock producers an opportunity to interact with the one local professional who can best guide them through health-related decisions about their animals – their veterinarian. Since the VFD’s implementation, many of these interactions have resulted in more effective and efficient use of these tools and consideration of disease prevention methods that preclude the need for antibiotics. These conversations are definitely a positive by-product of these new regulations.