Scours remains a persistent threat for beef producers who welcome calves into the world in cold conditions. Infectious agents that cause diarrhea in newborns tolerate low temperatures and wet ground, meaning that the onset of winter does nothing to reduce the prevalence of these pathogens on farms.

Viruses such as rotavirus and coronavirus, bacteria like E. coli, and parasites including Cryptosporidium are commonly present in adult cattle feces and they are spread through the calving environment when animals congregate and shed naturally as they approach parturition. These pathogens are not seasonal visitors; they are already present and can exploit any situation in which young calves have reduced resistance.

Cold weather compounds the biological challenge by undermining calf vigor and early nursing success. A calf that is born into wind, mud or snow needs to rise and suckle promptly to secure antibodies from colostrum, the first milk that delivers passive immunity. When chilling delays that process, the window for protection narrows and the calf enters a precarious state in which exposure to infectious agents more readily leads to illness.

Persistent dampness in calving grounds increases environmental contamination and calves that are delayed in nursing remain susceptible at precisely the time when pathogens are most concentrated at ground level.

Rural producers know that shelter and bedding are not luxuries in a winter calving program; they are practical defenses against disease transmission that can quickly escalate into a herd problem. Keeping calving areas dry and as free of manure as possible reduces the opportunity for fecal–oral contact that drives calf diarrhea outbreaks.

Careful management of cow nutrition and colostrum is central to disease resistance, as a properly fed cow is more capable of producing high-quality colostrum that delivers strong passive immunity to her calf. When that foundation is paired with timely veterinary involvement to identify and treat sick calves, producers are better positioned to control scours without depending on warmer weather to reduce disease pressure.