Mart McNutt knows what progress is in combating neonatal calf scours. The Tryon, NE, rancher has hacked calf death loss due to scours in his 800- to 900-head, March-calving, cow herd from a 1995-1999 average of 8-10% to zero in 2000-2004. In fact, the last calves he treated for scours in the system were four head back in 2000.
What's more, treatment expenses incurred during his past four calving seasons have averaged $128.83/year. That's just 4% of the $3,114.18/year his herd had averaged over the 1995-1999 calving seasons. McNutt estimates his change in calving management provides $40,000 to $50,000/year in added revenue by virtue of more weaned calves, better calf performance and reduced treatment expenses.
What's the secret? Healthier calves? Cleaner environment? Reduced disease load? Actually, it's a combination of all those factors, says Dave Smith, DVM.
Neonatal calf scours is a multifactorial disease, says the University of Nebraska-Lincoln (UNL) Extension veterinarian. The ideal scenario for an outbreak is to have susceptible hosts (naïve calves) existing in an environment (infected communal calving area) that's conducive to the proliferation of (and continued exposure of the host to) the disease agent, be it E. coli, Salmonella, rotavirus, cryptosporidia, etc.
Smith says even the healthiest calf can fall prey — particularly in the wet, muddy conditions common to spring calving periods — if the pathogen load is high enough, or the exposure long enough, to overcome the passive immunity provided by the calf's mother.
And that's the idea behind the UNL-developed Sandhills Calving System (SCS). Named after the Sandhills area of north-central Nebraska where it was tested, SCS is a system that utilizes a series of calving pastures to minimize newborn calves' contact with disease agents. The idea is to minimize both the disease load and newborns' exposure to the disease agents until their immune systems have sufficiently matured to better withstand them.
“We're trying to recreate the conditions of the first week of calving season during each of the remaining weeks of the calving season. We want a clean calving area without the presence of older calves that may be shedding pathogens,” Smith says. “I like to say we're creating eight, one-week seasons rather than one, eight-week season.”
Adopted in 2000, SCS consists of a series of large contiguous pastures. Learn more about the SCS system at: http://vbms.unl.edu/extension/ext_beef.shtml. Here's how it works:
Cows are turned into the first calving pasture (see Figure 1 on page 84) as soon as the first calves are born, and calving continues for two weeks.
After two weeks, the cows that haven't calved are moved to Pasture 2, with cow-calf pairs remaining behind in Pasture 1.
After a week of calving in Pasture 2, the cows that haven't calved are moved to Pasture 3, and cow-calf pairs born in Pasture 2 remain in Pasture 2.
With each subsequent week, cows that haven't calved are moved to a new pasture, and pairs remain in their pasture of birth.
The result, Smith says, is multiple pastures, each with calves within one week of age of each other. Cattle from different pastures can be commingled after the youngest calf is four weeks of age.
The segregation of calves by age prevents the transfer of pathogens from older to younger calves. In addition, moving pregnant cows to new calving pastures helps minimize the pathogen load in the environment, as well as a newborn calf's contact time with those pathogens.
“We had E. coli, crypto, coronavirus. We had it all. We put disease on top of disease in our old calving scheme,” McNutt says. “Then we stressed the calves even more by moving the day-old pairs to new pasture.
“With the Sandhills system, we're seeing a lot healthier calves. We're calving one week later than before but still branding at the same time in mid May and maintaining weights,” he says.
A Controlled grazing test
A second SCS trial was conducted on Gail Nason's rotational grazing operation, also near Tryon. She calves 400 cows in 60 days or less beginning in mid May as cows are moved through a series of pastures every two to four days. Both Nasons and McNutt's herds utilize the services of the same veterinarian, Tim Knott of the Sandhills Veterinary Clinic in Arthur, NE.
In the 1999 and 2000 calving seasons, prior to SCS adoption, Nason's herd posted a 6.5% death loss rate (28 deaths in 433 births), and 11.9% (48 deaths in 402 total births), respectively. Neonatal scours caused by rotavirus was found to be the main culprit (see Figure 2).
“I was at my wit's end,” Nason says. “Dr. Knott told me of the Sandhills system, and we brought Dr. Smith on board. Through trial and error, we developed our program. Since 2003 we've lost only one calf to scours. I'd never do anything else. It's the most beneficial practice I've ever seen.”
Nason says implementing SCS, not counting the labor and treatment savings, has probably meant an extra $10,000 in revenue just in the value of the calves saved.
To integrate SCS into her intensive pasture system, Nason continues to move groups of cattle throughout the calving season as necessary for proper forage utilization. However, every 10 days, or whenever 100 calves are born, she divides the herd by sorting out cows that haven't calved from the cow-calf pairs of the preceding group.
The result is that the number of calves in any pasture group never exceeds 100 and all calves within a group are within 10 days of age. The pasture groups are commingled after the youngest calf turns four weeks old.
While the application details of SCS differ between the two herds mentioned above, Smith says the key component is constant. That's the age segregation of calves and the movement to new pastures of cows that haven't calved rather than moving pairs.
“Segregating calves by age prevents the transfer of pathogens from older calves to younger calves,” Smith says. “Meanwhile, routinely moving heavy cows to new pastures prevents pathogen buildup in the calving environment over the course of the calving season, which would result in the exposure of the latest-born calves to an overwhelming dose load of pathogens.”
Smith has conducted a series of six SCS workshops for producers since January. He says the response has been very positive, with 55% of attendees in the first meeting indicating they intended to implement SCS in their herd “soon.”
Though the SCS concept hasn't been tested outside Nebraska, Smith says its applicability should be widespread. He knows of about a dozen operations in Nebraska and neighboring states that have practiced SCS for at least one year or more.
“The program was designed for beef operations typical of western Nebraska — larger herds on larger acreages,” Smith says. “But the age segregation of calves is the most important factor, not the number of acres and stocking density, so it should work for smaller herds on smaller acreages, as well.”
Implementing SCS isn't without its challenges, however, he points out. In some cases, cross-fencing is necessary. Making sure there's water access for the groups is another concern.
“Feed delivery in a spring-calving operation might entail more labor, as well,” Smith points out. “And, we like to encourage such producers to vary their feeding locations within any given pasture.”