The trouble with calf scours is that it is not a single disease that causes it. Rather it is a clinical sign that is associated with several diseases. Despite it having many causes one common sign is your calves having diarrhea. Regardless of what is causing it diarrhea prevents the absorption of fluids in the intestines. It is because of this that the onset of calf scours is very serious.
As any producer will tell you it is something that is very serious. Calf scours is the primary cause of death in calves from 2 to 30 days of age. However, despite the seriousness of this disease, it is fairly treatable. The leading cause of death from this disease is dehydration from fluid loss. Let us look at some ways to both treat and prevent calf scours from taking their toll on your calf herd.
What causes calf scours?
As I have mentioned above it is not one single disease that will cause scours to show up. When it comes to the known causes they can be divided into 2 categories: Noninfectious and Infectious causes. The noninfectious are often referred to as contributing factors. Whatever you want to call them there are interesting interactions between the noninfectious and the infectious causes. Trying to prevent infectious causes usually is pointless unless you take serious control of the non-infectious causes.
Noninfectious causes
Your noninfectious causes are often what you might call shortcomings in calf management. Things like nutritional deficiencies, inadequate environment, and not enough attention to the calf. Or it could possibly be a combination of all 3 of these.
Nutritional deficiencies of the cow, especially in the last trimester, are a major cause. When the nutritional demands are not being met both the quality and quantity of the colostrum will be affected. The cow not getting enough energy and protein can cause this. Deficiencies in both vitamins A and E have also been associated with a greater incidence of calf scours.
Muddy lots, crowding contaminated lots, calving heifers and cows together, and weather factors can cause stress to the newborn calf. When they are stressed this increases their chance of being exposed to infectious causes. A cold wet calf will often lack the vigor to nurse sufficient colostrum early in its life.
Insufficient attention to the calf will be an issue during difficult births or bad weather conditions. When the calf is born they lack the antibodies to fight scours This is why it is important for them to drink its colostrum right after they are born. All of the antibodies they will need are based on that colostrum. The longer they take to drink it the less effective it will be.
Infectious causes
Scours pathogens are viruses, bacteria, and microscopic parasites. The damage that these pathogens do will be in the intestinal tract. They cause the cells of the intestinal lining to malfunction and die. When the linings are damaged it makes it difficult to absorb the milk that is ingested.
E. coli seems to be the single most important cause of bacterial scours in calves. The K99 strain causes diarrhea by impairing the ability of the intestines to digest and absorb milk nutrients. Most newborn calves will pick this up from the environment if sanitation is marginal. This particular strain, however, is only capable of causing scours when the calf is under a week old.
Rotavirus, coronavirus, and a protozoan parasite called Cryptosporidia can cause damage to intestine walls. Healthy cows and heifers carry them through their manure and release them into the environment. The scours they cause tend to be yellow and watery. Because they are not susceptible to antibiotics the only treatment is replacing the lost fluids in the calf till the intestine wall is repaired.
Symptoms
As is well known one of the main symptoms of scours is diarrhea. A pathogen damages the intestine, preventing it from absorbing water and nutrients. The calf loses a large portion of its nutrients as a result. Because of this treating the diarrhea is the main focus. The symptoms of dehydration, such as sunken eyes, weakness, and dryness of mouth, are signs to look out for.
Acidosis is another sign that your calf night has scoured. The loss of salts creates an imbalance in the normal pH of the calf’s system causing acidity to take over. Calves with acidosis are weak and coordinated, They will show a drunken kind of wobbly gait when they walk. When you make them nurse their suckle response is just a weak chewing motion. As it worsens the calf cannot stand and will become lethargic and sleepy.
In colder weather, another common problem with calf scours is low blood sugar. Having scours will prevent them from absorbing the milk’s nutrients, so they won’t be able to replenish their body’s sugar reserves. If a calf has low blood sugar it will generally develop subnormal temperatures as they lose its ability to maintain its body heat. Low blood sugar also contributes to weakness and lethargy-induced acidosis.
Treatment of scours
When it comes to treating calf scours the main treatment is replacing fluid losses from diarrhea. Oftentimes the intestinal wall will repair itself so you need to provide fluids to keep the calf healthy. Young calves are more prone to scours because of their liquid diet. They are still nursing off of their mommas and they have yet to begin eating more solid foods such as forages and feed. Another factor to consider is that at birth according to research like that from the Texas AgriLife Extension, a calf is approximately 70% water at birth.
The type of treatment that you will need to use depends on the severity of the calf’s dehydration. If they are light to moderately dehydrated then you can use oral rehydration solutions. Severe dehydration will require an IV solution to get them back to where they need to be. One thing to note is that even though they are receiving electrolytes they will still need milk or milk replacer to supply them with energy and protein.
photo courtesy of Cargill
It is nearly impossible to feed a calf too many electrolytes but giving them too little is a common problem. To calculate how much liquid they need, multiply the weight of the calf by the percentage of dehydration, and divide by 2 to get quarts.
Being able to use antibiotics will depend on what is causing the scours. If rotavirus and the like are what is causing it then it will be basically useless to use them.
Prevention
The economic benefits of prevention far outweigh that of treatment. It is the most important and cost-effective way to invest your time. When it comes to prevention there are 3 main areas to look at.
Using good hygiene will minimize exposure which will prevent the disease. When it comes to improving sanitation there are many things that you can go with. Improving the general sanitation of the calving lots, disinfection of calving pens in between uses, and sanitizing calf treatment equipment are options. Isolating scouring calves is another step.
When it comes to prevention making sure the calf gets enough colostrum is key. It is the single most important way to determine the calf’s immune system in early life. Not doing this can increase the calf’s risk of getting sick 3x-10x. I talk about the importance of colostrum in a previous post “5 astonishing truths about colostrum to start calves right”.
Lastly, vaccinate your cows prior to calving. Proper vaccination against E. coli and rotavirus and coronavirus is important. It will increase the antibodies that she will pass to the calf through her colostrum.