Enteritis in Cows: Causes of Intestinal Inflammation and Diarrhea

Enteritis is inflammation of the small intestine, and in cattle it commonly leads to diarrhea, fluid loss, poor nutrient absorption, and weakness. In calves, people often use the word scours for this syndrome. The problem is not always a single disease. Instead, enteritis is often the visible result of infection, feeding issues, environmental stress, or several factors happening at once.

In young calves, enteritis can become serious fast because they have limited energy reserves and lose water quickly. Merck notes that clinical signs of dehydration may not be obvious until a calf has already lost at least 6% of body weight in fluid. That is why a calf with ongoing diarrhea, reduced nursing, or depression should be assessed promptly by your vet.

Adult cattle can also develop enteritis, although the causes may differ. Some adult cases are linked to contagious conditions such as salmonellosis or winter dysentery, while others involve severe intestinal disease like hemorrhagic bowel syndrome. In lactating cows, diarrhea may also be accompanied by a sudden drop in milk production, abdominal pain, or dark feces.

The good news is that many cases improve when dehydration, electrolyte loss, and the underlying trigger are addressed early. The right plan depends on the animal's age, severity, herd history, and whether your vet suspects an infectious outbreak.

Enteritis in cattle has both infectious and noninfectious causes. In calves, common infectious triggers include rotavirus, coronavirus, Cryptosporidium parvum, Salmonella spp., and some pathogenic E. coli. Mixed infections are common, and they often make diarrhea more severe or longer lasting. Merck notes that cryptosporidiosis is especially important in calves 5-15 days old, while mixed infections with crypto, rotavirus, and coronavirus can lead to persistent diarrhea, emaciation, and death.

Management factors strongly influence whether exposure turns into disease. Inadequate colostrum intake, crowding, dirty calving areas, contaminated feeding equipment, wet bedding, cold stress, transport stress, and sudden feed changes all increase risk. Beef Quality Assurance guidance emphasizes that hygiene, infection control, environmental management, and timely colostrum intake are among the most important preventive measures for scouring calves.

Diet can also play a role. Overfeeding milk or milk replacer, inconsistent mixing, abrupt ration changes, poor-quality feed, or nutritional imbalance can contribute to diarrhea, especially in young calves. These cases may begin with a calf that still seems bright and hungry, but ongoing fluid loss can still become dangerous if the feeding issue is not corrected.

In adult cattle, causes broaden to include salmonellosis, winter dysentery associated with bovine coronavirus, and severe focal intestinal disease such as hemorrhagic bowel syndrome. Stress, high-density housing, contaminated water, and herd-level exposure can all contribute. Because some causes are contagious and some are zoonotic, your vet may recommend isolation and extra biosecurity while the cause is being worked up.

Your vet usually starts with the basics: age of the animal, duration of diarrhea, appetite, nursing behavior, hydration status, temperature, manure appearance, and whether other cattle are affected. A physical exam helps estimate dehydration, weakness, abdominal pain, and whether the problem looks limited to the gut or has become systemic.

A definite cause usually cannot be diagnosed from appearance alone. Merck states that clinical findings may suggest a presumptive diagnosis, but fecal testing or postmortem examination is often needed to identify the specific pathogen. Your vet may collect fresh feces from several untreated calves early in the course of disease, use calf-side antigen tests, or submit samples to a diagnostic laboratory for culture, PCR, parasite testing, or toxin evaluation.

Bloodwork can help assess how sick the animal is, even when it does not identify the exact cause. Electrolyte panels, blood gas testing, glucose, and hematology can show dehydration, acidosis, electrolyte imbalance, and hypoglycemia. These results help your vet decide whether oral fluids are enough or whether IV fluids, anti-inflammatory support, antimicrobials for systemic illness, or hospitalization are more appropriate.

If an adult cow has severe abdominal pain, scant dark feces, distension, or suspected obstruction, your vet may recommend ultrasound, rectal exam, exploratory surgery, or necropsy in herd outbreaks. That is especially important when conditions like hemorrhagic bowel syndrome, salmonellosis, or other surgical intestinal disease are on the list.

Prevention starts before diarrhea appears. Good dam nutrition, clean calving areas, prompt colostrum intake, and lower pathogen exposure are the foundation. Beef Quality Assurance recommends that calves receive colostrum in the first four hours after birth, and it highlights hygiene, infection control, and environmental management as key tools for preventing scours outbreaks.

Keep bedding dry, reduce crowding, clean bottles and feeding tools thoroughly, and separate younger calves from older sick animals when possible. Moist, contaminated environments allow many pathogens to spread more easily. This matters especially for Cryptosporidium, whose oocysts can survive for months in cool, moist conditions and resist many common disinfectants.

Work with your vet on herd-specific prevention. That may include reviewing colostrum quality and timing, vaccination of pregnant cows or heifers where appropriate, calf housing design, feeding consistency, water sanitation, and outbreak testing. Merck notes that total prevention is unrealistic in neonatal diarrhea, so the practical goal is to reduce exposure and improve calf resistance.

If diarrhea starts appearing in multiple calves, act early. Isolate affected animals, step up sanitation, track ages and symptoms, and contact your vet before losses mount. Fast response can protect both the sick animal and the rest of the herd.