Through the fall of 2007, the sale price for a five-weight calf averaged around $685. Early signs suggest this year’s calf and feeder market should remain strong as herd expansion has stalled.
Even in a poor market year, a calf that dies shortly after birth represents a significant loss, and a high mortality rate can mean the difference between profit and loss for a ranch. With that in mind, it becomes increasingly important for producers to use all available tools to assure the health of their calves and, particularly, to protect them from the pathogens that cause scours.
Kevin Hill, DVM, is a technical services veterinarian with Schering-Plough Animal Health, based in Utah. He says calf scours is the leading cause of death loss in calves, resulting in an estimated $50 million to $120 million annual loss to the cattle industry.
Labor and treatment costs and long-term performance losses for sick calves add to the expense for individual producers.
Fortunately, ranchers and veterinarians have opportunities, through planning and management, to minimize or even eliminate losses from calf scours. Hill says prevention of calf scours boils down to just two basic strategies.
1. Maximize the immune-system protection by improving the antibody production by the cow and by assuring adequate and timely colostrum intake by the calf.
2. Minimize the exposure of the calf to disease-causing organisms by eliminating contact with manure.
Begin with the cow
Hill notes that the fetus grows rapidly during the 60 days prior to calving, and the dam’s nutritional requirements increase sharply. “Research shows that substandard nutrition during that period can have a detrimental impact on quantity and quality of colostrum produced, reducing the newborn calf’s ability to withstand environmental stresses.
“Pay particular attention to energy, protein, mineral and vitamin levels,” Hill says. A medium-size cow should consume at least 11 pounds of TDN and 2 pounds of crude protein per day. “At a minimum, all minerals and vitamins should be supplied at NRC-recommended levels, with particular attention to copper, selenium, zinc and vitamin A, which can directly impact the immune function of both the dam and the calf.”
Vaccinating cows using products intended for scours prevention can improve the quality of colostrum and thus improve the passive immunity they pass along to their calves at birth. Hill explains that cows develop antibodies to organisms to which they have been naturally exposed or to those for which they have been vaccinated. Vaccination cannot prevent exposure, he says, but antibodies from colostrum help the calf’s immune system respond to infectious challenge and can significantly reduce sickness and death loss.
Hill notes that producers need to follow label directions carefully, vaccinating cows about six weeks before calving for good results. Thus, it probably entails extra animal handling but pays dividends, especially in herds with a history of calf scours. He stresses, however, that vaccines alone, without good nutrition and management, cannot guarantee protection.
Get it to the calf
Once you have addressed the cow’s immune system with good nutrition and vaccinations, the next step is to help her pass it on to her calf through colostrum management.
Calves, Hill says, cannot manufacture their own antibodies quickly enough to provide protection during the first few months of life, so their only chance is to get those antibodies from their dam through her colostrum.
The calf needs to absorb antibodies from colostrum into the bloodstream for lasting protection, and it needs to happen quickly. Within 12 hours after birth, the efficiency of antibody absorption in the gut of the calf has dropped by more than half, Hill says. By 24 hours after birth, little or no absorption will occur.
He stresses the importance of assisting any calf that has not stood to nurse within four to five hours of birth. If a calf requires assistance during delivery or has a stressful start, he suggests tube feeding colostrum as soon as possible. In the case of dystocia, he adds, you probably already have the cow restrained, so you can milk her out and feed the calf.
High-quality colostrum replacements can work, he adds, but are not as good as the natural product from the dam.
A high level of exposure to infectious bacteria, viruses and parasites can overwhelm the immune system of almost any calf, and good hygiene at calving is critical for scours prevention. Hill notes that the pathogens involved in calf scours are transmitted from one animal to another through manure. Calves can become infected through an open umbilicus if they are born on contaminated calving grounds, or by suckling dirty teats.
Reserving a suitable area for calving is critical, particularly when wet conditions create stress and increase the possibility of exposure.
Hill notes that most producers have selected calving pastures based on soil types, slope or other factors that provide good drainage and stay relatively dry during the calving season. A problem, he says, is that sometimes producers move all their cows to that “best spot” for the entire calving season.
He suggests there could be advantages to reserving that best spot for cows that calve during the periods of highest risk. In northern climates, for example, he says the ground often remains frozen through the first weeks of the calving season, meaning wet, muddy conditions are not a problem. Producers might keep their cows in other areas for calving through this period, then, as the snow melts and conditions turn sloppy, move the cows that have not calved to the clean, well-drained calving pasture.
Another potential problem, he says, is when producers move heavy cows into small pastures near the house for easy monitoring, or into a barn for calving during inclement weather. Manure, and thus pathogens, builds up in these confined areas, practically assuring exposure for later calves.
University of Nebraska Extension veterinarian David Smith agrees, saying producers need to weigh the risk of bad weather against that of scours. In a herd where scouring problems are rare, but where the location and calving season pose a high risk of adverse weather, a confined calving area might be a good choice. But in herds where scouring occurs, spreading cows out for calving becomes a higher priority than protecting them from the weather.
Segregate age groups
Forget the one-room schoolhouse — calves do better in classrooms with their own age group. Smith explains that pathogen levels are low when the season’s first calves are born, and scouring incidence is low. But once a few calves develop scours, they shed large numbers of pathogens onto the pasture. Calves born a week or two later have more exposure, and pathogen levels and incidence of scours tend to snowball as the season progresses.
At the same time, acquired or passive immunity tends to decline before a calf’s active immune system is fully developed. This creates a window of vulnerability and, Smith says, explains why most cases of scours occur during the second and third weeks of calves’ lives.
With these exposure and susceptibility concerns in mind, Smith and other veterinarians in Nebraska introduced the Sandhills Calving System in 2000. This system is designed to interrupt the cycle of infection by segregating calves by age.
The basic idea, Smith explains, is to use multiple calving pastures for a single cow herd. All the cows start out in pasture 1 as calving begins. After a week to 10 days, cows that have not yet calved move to pasture 2. This process repeats through the calving season, with cows moving to fresh pasture for calving and groups of pairs remaining on the pastures where the calves were born. Pairs can be co-mingled once calves reach 4 weeks of age.
Smith says producers who have adopted the Sandhills system have had excellent success in preventing scours, with some saying they have reduced their need to treat scouring calves to virtually zero. The first Nebraska ranch to incorporate the system back in 2000 still uses it today, as do most others that have tried it. Also, he says, interest is spreading as people realize the system is not just for Nebraska or for large producers. “People are figuring out ways to use it in smaller herds and in different areas,” he says.
Hill also advocates the Sandhills system, but adds that producers can adapt the general concept of separating older calves from newborns, even if they do not use the complete system. If land is limited, for example, he says a producer might use four calving pastures instead of the eight prescribed in the Sandhills system, moving cows every two weeks rather than every week.
Smith agrees that there are other ways to accomplish the same goal, but cautions cattle producers not to compromise on the basic principles to the point that the system fails. He says that in some cases ranchers have been successful moving pairs daily from a single large calving pasture into multiple one-week age-segregated pastures. In a large, lightly stocked calving pasture, this could reduce exposure for newborn calves, but doesn’t work as well in smaller calving lots where manure builds up quickly.
So, start early with cow nutrition and vaccinations, try to assure that every calf gets its colostrum, minimize exposure in the calving pasture and have a full complement of healthy calves to sell in the fall.
For more detailed information about the Sandhills Calving Method, including case studies
of ranches that have used the method, follow this link (PDF format).