Understanding how to weaken Clostridium perfringens’ effects on calves
Using the “epidemiologic triad” to understand calf illnesses caused by Clostridium perfringens is helpful in keeping calves healthy. To recap the explanation in the last column, the “epidemiologic triad” is a big-picture view of animal diseases. It’s the recognition that the germ, the animal, and their environments all interact with each other to determine whether an infectious disease will rear its ugly head or not.
Clostridium perfringens infections are pertinent examples of how the three parts of the epidemiologic triad interrelate. This germ is very common and persistent in manure and soil. It does its damage by producing toxins that damage the gut and sometimes other organs. The “animal” corner of the triangle helps us understand that calves can gain immunity against the effects of clostridial toxins. And, as is the case with calf gut germs in general, the environment of the calving lot or barn is an important aspect too.
Now that – thanks to the epidemiologic triad – we better understand how Clostridium perfringens causes calf illness, we can potentially start to understand what to do about it.
Let’s start with the germ itself. Could we just get rid of Clostridium perfringens in our cattle operations? Not a chance. As mentioned last time, some types of Clostridium perfringens have adapted to survive very well in pens, lots, and dirty bedding. Even if calves and cows are put into a sterile environment, the premises would quickly become contaminated by the germs normally shed in cattle manure.
How about the animal itself? Could we bolster the calf’s immune system so it’s not affected by these commonly-encountered germs? It turns out that might be possible. Calves get more resistant to the effects of Clostridium perfringens Types A, C, and E as they get older. But before that, immunity definitely plays a role.
Young calves gain immunity against harmful germs in one of two ways. First is the colostrum they get from their mother during the first hours of life. This first milk is rich in antibodies that attack specific germs, protecting the calf during its first weeks and months. The antibodies in colostrum reflect those made by the cow’s immune system, so we can affect their amount and variety by vaccinating the mother during late pregnancy with “scour shots.”
Clostridium perfringens Types C and D are common components of these vaccines. They provide protection against beta and epsilon toxins – not the alpha toxin produced by the frequently-identified Clostridium perfringens Type A infections. A separate Type A vaccine is marketed for that purpose. To protect against all those types of toxins, both vaccines are necessary.
What about vaccinating the baby calf itself? While most vaccines don’t work very well in days-old calves, evidence suggests that Clostridial vaccines might be an exception. Even so, vaccines still take time to work: vaccinating a day-old calf might only be useful in preventing infections seen later in life. Typical “7-way” vaccines aren’t formulated to protect against alpha toxin. A separate Type A vaccine is considered necessary to protect against that version of the germ.
The final corner of the triad is the environment. While we can’t rid our cattle lots of Clostridium perfringens, we can cut down on their numbers. Regular cleaning of pens, lots, and calving sheds should be part of our efforts to minimize the influence Clostridium perfringens has on our calves.
There’s another environment to consider for Clostridium perfringens, too – the environment inside the calf’s gut. When a calf’s milk intake changes erratically or rapidly, Clostridium perfringens can exponentially grow and produce the harmful toxins. While it would be impractical to influence milk intake in our beef calves, producers can at least be aware of those conditions. The story is different for calves on milk replacer, for which we can directly work to eliminate sudden changes in milk intake.
One person in your community who has dealt with issues such as Clostridium perfringens is your veterinarian. When it comes to the specific challenges your operation faces with this and other germs this calving season, there’s no one better to lay out the possible solutions. Make sure you enlist their advice and experience when you suspect Clostridial problems in your calves this season.
Russ Daly, DVM, is the Extension veterinarian at South Dakota State University. He can be reached via e-mail at firstname.lastname@example.org or at 605-688-5171.