Categorize Neonatal Calf Enteritis to Guide Therapy Decisions
Millions of dollars have been invested in product research and development in the past decade to address neonatal enteritis. Even so, it remains the most common cause of illness and death in beef and dairy calves between 2 days and 30 days of age.
While veterinarians and cattlemen tend to lump infectious enteritis into a single group of problems, Dr. Franklyn Garry, College of Veterinary Medicine, Colorado State University advises a different approach1.
He characterizes calf enteritis based on two different groups of pathophysiologic conditions:
• Group 1 includes viral pathogens, rotavirus and coronavirus and the protozoal agent Cryptosporidium parvum. Garry says these are non-invasive, cause diarrhea with associated fluid and electrolyte losses that respond well to fluid therapy. They are not effectively addressed by antibiotic treatment.
• Group 2 includes bacterial enteric pathogens that cause different pathophysiologic changes including significant inflammatory response and invasion beyond the intestinal lining. The most common of these is Salmonella spp and enteropathogenic E. coli. Garry also includes clostridial enteritis in this group. Antibiotic use has a valuable role with this group.
“Of course, there are exceptions to any rule of thumb, but I have consistently found that categorizing calf enteritis problems like this (see figure 1) is helpful for establishing prognosis, guiding therapy, and developing preventive measures,” he says.
The Role Of Fluid Therapy
For Group 1 pathogens, Garry says fluid therapy is the key to successful treatment of calf scours.
“To correct these scours, the oral fluids you administer need to have the right composition of electrolytes, glucose or glycine to promote electrolyte and fluid absorption, and an appropriate concentration of an alkalinizing agent,” he says.
Be proactive in getting fluids to the calf, adds Corale Dorn, DVM, Dells Veterinary Services, PC, Dell Rapids, S.D. “Scours can happen quickly, and calves can die really fast, so you don’t want to wait on lab results,” she says. “Diagnostics are important, but (in the moment) take care of what’s right in front of you.”2
Even severely affected calves are often saved if given IV replacement fluids early enough, but too often beef and dairy producers commonly default to using oral antibiotics for Group 1 pathogens. This strategy is counterproductive and can cause harm — something producers need to be educated on from veterinarians, Garry says.
In some scenarios, veterinarians might find it difficult to use fluid therapy of any kind. In that situation, Andrea Lear recommends practitioners consider using an IV bolus of 100 milligrams per kilogram of dextrose along
with hypertonic bicarbonate bolus at one time.
“That gets some energy into them and resuscitates them, and then you can switch them over to oral resuscitation,” says Lear, DVM, Large Animal Clinical Sciences, University of Tennessee.3
A Severe Disease Threat
Group 2 pathogens have toxic and invasive capabilities and can produce inflammatory responses.
Garry says the calf’s intestinal tract will be affected. Feces will be abnormal, but usually not in the high-volume, fluid amount as with classic calf scours.
Instead, affected calves might have blood and protein in their feces or develop ileus and abdominal filling with minimal feces.
“Affected calves may die acutely without preceding signs of diarrhea,” Garry says. “Calves commonly show multisystemic signs such as pneumonia, meningitis, renal disease and septic arthritis.”
With disease from Group 2 pathogens, Garry recommends parenteral antibiotics, especially if there is vascular damage present.
“Some anecdotal evidence suggests that off-label oral use of penicillin for clostridial enteritis, or TMP-sulfa for salmonellosis may help, but I have not seen any published trials confirming the efficacy of these treatments,” he adds.
Regardless of the treatment method, Garry says the prognosis for calves affected by Group 2 pathogens, particularly those with septicemia, is guarded to poor.
Management To Minimize Pathogen Spread
On the farm, infectious disease outbreaks are a function of the level of resistance versus level of challenge.
“We see outbreaks of disease when resistance is low or challenge is high, or both,” Garry says.
Factors such as good adaptation to extra-uterine life, maternal care, nutrition, dryness and warmth and good colostrum consumption, especially, can help neonatal calves resist disease. Crowding, exposure to shedding animals and hygiene are also important considerations.
“Colostral transfer of immunoglobulin is particularly important for preventing severe disease,” Garry says. “Since these bacterial problems involve toxins and bacterian invasion, circulating IgG can be quite effective in limiting disease severity and occurrence of bacteremia or toxemia, such as clostridial exotoxin movement.”
Conversely, for calf scours manifested by viral/protozoal enteritis, colostrum acquisition and IgG transfer have a much more limited effect.
“While vaccination is important, good management practices that emphasize decreased dystocia, improved nutrition and protection from environmental pressures become more critical,” he adds. “These are reasons the Sandhills calving method and similar strategies to decrease calf exposure to contagious older calves are so successful.”
1Garry Franklyn. Differentiating causes of neonatal calf enteritis to enhance management and prevention. AABP Annual Conference Proceedings. Vol. 53, No. 2, September 2020.
2Dorn Corale. But what does it taste like? How to get your clients through a complete scour workup in their herd. AABP Recent Graduate Conference Proceedings. Vol. 54, No. 1, February 2021.
3Lear Andrea. On farm calf assessment and practical fluid therapy. 53rd Annual Conference American Association Bovine Practitioners. 2020; 53:344-345.