Strategies to Combat Calf Scours
Strategies to Combat Calf Scours
Calf scours is the single most significant health threat to a calf in its first month of life, and it represents a direct correlation to your on-farm profits. For this reason, getting calves off to a healthy start should be a high priority during the upcoming calving season. Scours pose an economic threat to your dairy operation’s future. It is not just a frustrating event; it is a health setback that compromises the calf’s growth and, crucially, her performance once she joins the milking herd. Understanding the true, researched cost of scours is the first step toward building an effective defense.
Current veterinary and dairy science knowledge shows us that the impact of calf scours extends far beyond the initial treatment and potential death loss. Research has now led to the long-term damage caused by scours.
According to reports from the USDA National Animal Health Monitoring System (NAHMS), scours accounts for over 50% of all pre-weaning calf mortality. This high percentage shows how dangerous scours can become, and it is a greater threat to calf survival than any other disease, including respiratory illness (pneumonia), which is the second most common cause. Because scours is often a “multi-factorial” disease driven by a combination of pathogen exposure and possible weak immunity (colostrum failure), a large percentage of these losses are considered preventable through effective management intervention.
The High Cost of Calf Scours
One of the most critical findings for dairy producers is the impact on future milk production. Research consistently links a single case of calf scours to a reduction of approximately 700-750 pounds of milk in the first lactation alone. This reduction is believed to be a consequence of the damaged intestinal tract, which limits nutrient absorption and long-term growth potential.
Additionally, scours survivors often suffer from stunted growth, resulting in lower average daily gains (ADG) during the pre-weaning phase. This developmental delay means these heifers take longer to reach the target breeding weight. Studies indicate that heifers treated for scours are significantly more likely to calve after 24 months of age, substantially increasing your replacement heifer costs.
Prevention is Key
It’s easier to implement some preventative measures than to battle a case of scours going through your calves. First, you want to get a plan together. A successful program requires a multi-layered approach that both promotes strong calf immunity and drastically reduces the environmental pathogen load.
This starts with making sure the calf receives good colostrum within the first couple of hours. The transfer of passive immunity via colostrum is the most critical factor in a calf’s survival and future health. In fact, according to the USDA, calves that do not receive colostrum are up to 50 times more likely to die within the first few weeks of life, primarily due to scours and pneumonia. The calf’s ability to absorb the crucial antibodies from colostrum is highest immediately after birth and then declines dramatically after a couple of hours. Dairy producers should routinely test all colostrum using a Brix refractometer, aiming for a concentration of immunoglobulin G (IgG) that corresponds to >22% Brix for high-quality defense.
If you have a cow lacking in colostrum, be ready to substitute some. This could include drenching, or if you have some extra frozen, have that on hand and thawed. When born, the calf’s gut closure is open and ready to quickly absorb colostrum. The calf’s gut closure begins rapidly after birth, meaning the ability to absorb crucial antibodies begins to decrease after 2 hours, and plummets after six hours. The first four quarts of colostrum must be delivered within 1 to 2 hours of birth to ensure maximum absorption.
The next step in prevention is keeping a sanitary and clean environment. Environmental management is key to breaking the cycle of infection by reducing the pathogen dose-load. Do this by keeping calving areas clean and sanitized. The calving pen must be a clean, dry, and well-bedded environment for every birth; it should never be used as a sick pen. The calf should be removed promptly after birth to a clean, individual pen to limit exposure to pathogens.
Sanitation
Furthermore, colostrum is the perfect growth medium for bacteria, which can interfere with IgG absorption. All collection buckets, bottles, and tube feeders should be thoroughly sanitized and dried after every use to minimize bacterial counts. Not only do you want to get colostrum to calves as soon as possible, but you also want to do it in a clean environment to prevent further sickness.
For both scour prevention and BVD prevention, sanitize feeding equipment. All equipment used for feeding milk or replacer, including nipples and tubing, requires complete scrubbing, disinfecting, and drying after every single feeding to eliminate the persistent threat of biofilm and pathogenic buildup. All of these prevention methods do take some time, but the time is justified by having healthy calves and more productive cows in the future.
By reducing the incidence of scours, you immediately slash costs associated with treatment, including medication, electrolytes, and the intensive labor required to nurse sick calves. So, while you may be putting in some labor on the prevention side of things with more cleaning, you should put in less labor than it would take to nurse sick calves back to health.
Later, we see this financially pay off. Calves that avoid scours maintain a healthy gut lining, leading to better feed efficiency and optimal average daily gain. We also see healthy cows that have not had scours go on to produce more milk when compared to cows that have had scours.
Focusing on colostrum management and top-notch cleanliness and hygiene ensures that your calves thrive, providing a healthy foundation for the next generation of highly productive milking cows.
By Jessica Graham
January 2026
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