Calf scours is a challenge that keeps cow/calf producers on edge, and for good reason. It’s the leading cause of financial loss in herds, hitting harder than any other health problem. What makes it so worrisome is how quickly it can show up and spread, much like wildfire sweeping through dry grass. To make matters worse, calf scours can be a bit of a puzzle, leaving many producers scratching their heads about what exactly they’re dealing with.
The tricky part about calf scours is that it isn’t just one disease—it’s a clinical sign linked to several different issues. No matter the underlying cause, the result is the same: diarrhea. This condition prevents the intestines from absorbing the fluids calves desperately need to stay healthy. Without proper intervention, this simple yet serious issue can escalate rapidly, making calf scours a significant concern for anyone raising calves.
Speaking to any seasoned producer, they’ll emphasize the severity of this issue. Calf scours is the leading cause of death for calves aged 2 to 30 days. The primary culprit isn’t the disease itself but the dehydration it causes. However, the good news is that calf scours are highly treatable with early and effective intervention. The key is to act swiftly and take the right steps to both treat and prevent it from wreaking havoc on your herd.
What causes calf scours?
As I mentioned above, not one disease will cause scours to show up. The known causes can be divided into two categories: non-infectious and infectious causes. The non-infectious are often referred to as contributing factors. Whatever you want to call them, there are interesting interactions between them. Preventing infectious causes is usually pointless unless you take profound control of the non-infectious causes.
Non-Infectious Causes: The Role of Management
Non-infectious causes of calf scours are often the result of how calves are managed and cared for rather than a specific pathogen or disease. These causes might not seem as urgent as infectious ones. Still, they play a significant role in setting the stage for scours to develop. It’s like creating the perfect storm. When calves are under stress or exposed to less-than-ideal conditions, their immune systems weaken, leaving them more vulnerable to infections. By addressing these factors, you’re not just avoiding scours but giving your calves the strongest possible start in life.
Poor nutrition, inadequate environments, and lack of attention to newborns are some of the most significant contributors to non-infectious calf scours. For example, suppose a cow doesn’t receive the proper nutrients during her last trimester. In that case, the quality and quantity of her colostrum may suffer. Without this vital first milk, calves miss out on critical antibodies that protect them from disease. Similarly, muddy, crowded calving areas and cold, wet weather can stress calves, making them less likely to nurse and more prone to illness. By focusing on these areas, you can dramatically reduce the chances of scours taking hold in your herd.
- Poor Nutrition for Pregnant Cows:
A cow’s diet during her last trimester directly affects the quality and quantity of colostrum. The calf is born with a weaker immune system if she doesn’t receive enough energy, protein, or vitamins (like A and E). This knowledge empowers you to ensure your cows get the proper nutrition, setting the stage for healthy calves.
- Stressful Environments:
Muddy, crowded lots or mixing calving cows with heifers can stress newborns, increasing their risk of infection. Cold, wet, or weak calves may struggle to nurse early, missing out on vital colostrum.
- Inadequate Calf Care:
Difficult births or bad weather can delay a calf’s first meal of colostrum. Since colostrum provides all the antibodies calves need to fight disease, any delay can make them more vulnerable to scours. Colostrum is the first milk produced by the cow after calving, and it is rich in antibodies that provide passive immunity to the calf. This early feeding is crucial in preventing calf scours.
Infectious Causes: What Pathogens Are to Blame?
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 is the single most important cause of bacterial scours in calves. The K99 strain causes diarrhea by impairing the intestines’ ability 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.
Rota virus, coronavirus, and a protozoan parasite called Cryptosporidia can damage intestine walls. Healthy cows and heifers carry these parasites 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 until the intestine wall is repaired.
Spotting the Symptoms: What to Watch For
As is well known, diarrhea is one of the main symptoms of scours. A pathogen damages the intestine, preventing it from absorbing water and nutrients. As a result, the calf loses a significant portion of its nutrients. Because of this, treating diarrhea is the main focus. Signs of dehydration, such as sunken eyes, weakness, and mouth dryness, are signs to look out for. Other symptoms include a loss of appetite, lethargy, and decreased body weight.
Acidosis is another sign that your calf might have scoured. The loss of salts creates an imbalance in the normal pH of the calf’s system, causing acidity to take over. In simpler terms, the calf’s body becomes more acidic than normal, which can lead to a range of symptoms. Calves with acidosis are weak and uncoordinated. 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. The calf cannot stand as it worsens and will become lethargic and sleepy.
Another common problem with calf scours in colder weather 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 it loses its ability to maintain body heat. Low blood sugar also contributes to weakness and lethargy-induced acidosis.
Treating Calf Scours: A Focus on Fluids
When it comes to treating calf scours, the primary treatment is replacing fluid losses from diarrhea. The intestinal wall will often 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 their mommas and have yet to begin eating more solid foods such as forages and feed. Another factor to consider is that, according to research from the Texas AgriLife Extension, a calf is approximately 70% water at birth.
The type of treatment you will need to use depends on the severity of the calf’s dehydration. You can use oral re-hydration solutions if the calf is light to moderately dehydrated. Severe dehydration will require an IV solution to get the calf back to where it needs to be. One thing to note is that even though the calf receives electrolytes, it will still need milk or milk replacement to supply it with energy and protein.
photo courtesy of Cargill
Feeding a calf too many electrolytes is nearly impossible, but giving them too little is a common problem. To calculate how much liquid they need, multiply the calf’s weight by the percentage of dehydration and divide by 2 to get quarts.
The ability to use antibiotics will depend on what is causing the scours. If rotavirus and the like are causing it, then it will be basically useless to use them.
Prevention: The Best Medicine
The economic benefits of prevention far outweigh those of treatment. Prevention is the most essential and cost-effective way to invest your time. There are three main areas to consider when it comes to prevention.
Using good hygiene will minimize exposure, which will prevent the disease. When it comes to improving sanitation, you can go with many things. The options include:
- Improving the general sanitation of the calving lots.
- Disinfecting calving pens between uses.
- Sanitizing calf treatment equipment.
Other ways to prevent scours
One essential step in preventing the spread of calf scours is isolating affected calves. Scouring calves can spread pathogens through their manure, contaminating the environment and exposing healthy calves to infection. By separating sick calves from the rest of the herd, you can minimize the risk of an outbreak spreading like wildfire. Isolation also allows you to focus on treating the sick calves without putting the rest of your herd at unnecessary risk. Think of it as creating a safe zone for your healthy calves while you work to get the others back on their feet.
Another critical prevention measure is ensuring that newborn calves receive enough high-quality colostrum. Colostrum is their first line of defense, providing essential antibodies that build up their immune systems. Without it, their risk of illness skyrockets, sometimes as much as three to ten times higher. This golden first milk is so important that it’s worth taking extra time to ensure each calf gets what it needs. If you’re curious to learn more about the power of colostrum, check out my previous post, “5 Astonishing Truths About Colostrum to Start Calves Right.“
Finally, vaccinating your cows before calving is a proactive way to protect your calves. Vaccines for diseases like E. coli, rotavirus, and coronavirus help boost the antibodies that the cow passes to her calf through colostrum. This boost gives calves a much-needed head start in their early days when they are most vulnerable. Vaccination is a straightforward step with huge benefits, helping to shield your herd from the potentially devastating effects of calf scours. By taking these preventative measures, you’re not just avoiding problems—you’re setting your herd up for long-term health and success.
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