Recurring calf scours can be a real killer for cow-calf beef operations. It ranks among the top causes of mortality for young calves across the nation. Cattlemen know that scours can range from mild conditions with loose stool, all the way to severe dehydration and death.
Halden Clark, DVM at the Great Plains Veterinary Educational Center, spoke at a Jan. 5 University of Nebraska Beefwatch webinar about ways to understand scours and prevent it from taking a toll in the herd.
There are numerous pathogens that can cause scours, including but not limited to rotavirus, bovine coronavirus, E. coli, salmonella and cryptosporidium, among others.
“Sick calves can be infected with more than one of these at one time,” Clark said. “Several of these pathogens are zoonotic, and they can infect people. You need to wear gloves and be careful when handling a sick calf.”
The risk factors for scours include wet, cool weather and mud that promotes the survival and spread of the pathogens. “High stocking density causes a higher pathogen load and more effective contacts,” Clark said. “Effective contact occurs when a susceptible calf contacts a calf that is actively shedding pathogens.”
He noted that early spring calving has more incidences of scours than late spring. Fall calving herds also experience less scours on average.
“The dairy industry prevents scours through sanitation,” Clark said. “They use calf hutches to prevent exposure of young calves to pathogens from other calves.” Pathogens causing scours can be picked up from fecal matter. “It could come nursing on a contaminated teat from their mother, or off the ground, at a water tank or through feedstuffs,” he explained.
“A severe outbreak can hit up to 100% of the calves in a herd,” Clark said. “Death rates can be up to 15% or higher, and it can be pretty horrible at times.”
Treating scours takes labor and expense, along with personal infection risk and an emotional cost of losing calves that were previously seemingly healthy. “There have been documented cases of 80% death loss in beef calves,” Clark added.
About 20 years ago, several ranch managers were experiencing severe annual scours outbreaks in their herds. One ranch, with 800 to 900 cows, had 7% to 14% death loss over a three-year period, and veterinary costs of about $3,000 a year dealing with these outbreaks.
Sandhills Calving System
The ranchers approached University of Nebraska-Lincoln researchers asking for solutions. In studying how the outbreaks occur, the researchers found something interesting. Early calves in those herds with outbreaks typically did not get sick, but later calves in the same herds exhibited significant signs of the disease. They figured out that there was a sequential buildup of pathogen loads over time.
Early calves may have had small amounts of pathogens, but through the course of the calving season, the pathogen loads increased through contact between calves until the later calves contracted larger pathogen loads that overwhelmed the immunity they received from their mother’s colostrum and their own immunity.
Out of this newfound knowledge, the Sandhills Calving System was born. “They designed this system to essentially restart the calving season every week on fresh ground,” Clark explained. “This system requires multiple calving pastures, and they need to be clean with no cattle exposure for weeks or months.”
Simply put, all cows and calves are placed in the first calving pasture for a week. After one week, the cows with calves stayed in that pasture, and the “heavy” pregnant cows were moved to the next calving pasture.
After another week, those that had calved stayed with their calves in that pasture, but the heavy cows were moved on to another calving pasture.
“If you had a two-month calving season, you would need eight pastures,” Clark said. The system very basically keeps fresh calves away from older calves entirely, protecting them from potential pathogens.
“All of the calves remain with their one-week cohorts until the youngest calves are 1 month old, before they can regroup the entire herd again,” Clark said.
When the ranch previously mentioned adopted the Sandhills Calving System in 2000, the results were immediate. Through three years of implementation, they had no calves die of scours during that period, and treated very few, if any. The ranch owner estimated that the move to this new system saved him $40,000 to $50,000 because he had more calves at weaning time and saved on veterinary expenses.
More than 40% of the Nebraska ranches with more than 200 cows have adopted some version of this calving system, in one form or another. In the central U.S. states, more than 27% of ranches have adopted a version of the Sandhills method. “I believe uptake has been remarkably rapid across the industry, which speaks to how well this system functions,” Clark said.
“This Sandhills Calving System is an example of how manipulating the system can cause the outcome to change dramatically,” Clark said. “It is possible that the same system would work for pen-calving, but we just don’t have the same level of data on that yet.”
View the entire webinar and numerous others from UNL Beefwatch by visiting beef.unl.edu.