By Victoria G. Myers
Progressive Farmer Senior Editor
For Brian Marshall, the clock starts the minute a new calf hits the ground. Within the first four or five hours, this Missouri producer makes sure newborns are given an immunity-building bolus to head off scours and pneumonia, and lessen stress.
Marshall manages the cattle side of Marshall and Fenner Farms, a family operation at Malta Bend. Today, this operation, which started around 1950, is home to four generations. Marshall and six family members run the farm, which includes 2,700 acres of row crops (soybeans, corn and wheat) and a cattle operation.
Most of the cows here are black Angus, with about 400 head making up the registered and commercial herd. The farm has developed a reputation for high-quality replacement females, as well as bulls. That means every calf represents a serious investment in both time and genetics.
This is both a spring- and a fall-calving operation. Artificial insemination (AI) is used on almost 90% of cows, with a majority of the herd employed to carry embryo transplants from the best quality cows.
"We have 12 donor cows, and we've been doing embryo transfers for about 10 years," Marshall said. "Over the past three years, we've also started doing some in vitro fertilization. It's pretty wild. But the turnover on the herd, the improvement in genetics, is so fast. It's 10 times faster than developing a herd traditionally."
The in vitro work is being done with one nearly 10-year-old cow, SAV Elba 4436, a high-valued investment whose calves are highly sought after in the Angus breed. Marshall said thanks to the in-vitro work, she has already produced 160 calves. Compared to a 12-year-old cow that carried 10 calves naturally in her lifetime, it's easy to see how much more productivity can be gained with the technology.
"With superior animals, this allows you to sort of push the button and try to get more of the better ones," Marshall says. "We use the commercial cows to carry those embryos, and our genetics just get stronger and better. Everything pushes forward faster."
PROTECTING THE INVESTMENT
Given the lengths this operation goes to for quality calves, it's easy to see why Marshall doesn't like to lose one. Unfortunately, like many other cattlemen, he's had to deal with scours in his spring calf crop.
"We lose some calves to scours every year, I think everybody does. But it can add up quick, you can lose 15 or 20, and that's what we want to avoid," he said.
Once scours hits an operation, it usually will be hardest on calves around 2 weeks of age. Dams and their calves have to be gathered up, treated with an antibiotic and often given oral fluid treatments to replace electrolytes and rehydrate affected calves. In some cases, a laboratory diagnosis may be needed to identify which pathogen is at the root of the outbreak.
Rotavirus and Bovine coronavirus are commonly associated with scours in calves. Parasites that cause problems include Cryptosporidium (crypto) and coccidia, and bacteria that can lead to scours include Escherichia coli (E. coli), Salmonella and Clostridium perfringens. Scours agents stay in the ground and can transfer to calves, especially under wet conditions.
MULTIPLE LINES OF PREVENTION
Marshall said in his experience, wet, damp and muddy conditions can be a trigger for the onset of scours. It's not a problem when the sun is shining and the ground is dry and warm. But in any spring-calving operation, those conditions aren't something you can order up.
"Being spring calvers, there are times we have to calve in the barn. We'll bed them with corn stalks and change those every two to three days to keep them dry. It's labor-intensive work calving in the barn, but these are valuable calves, and I don't want them in a snow drift somewhere."
He said the best option to head off problems is being able to switch pastures and keep calves on fresh ground. In some cases, that's not an option, so he adds other lines of prevention.
"We really believe prevention is just as easy as treatment, and it means you'll lose fewer calves. We vaccinate cows prior to calving, plus, we give the calf a preventative bolus," he said.
For cows, he uses Guardian, a vaccine that stimulates production of antibodies in the cow to infectious agents that can cause scours. The antibodies are then in the colostrum the newborn consumes shortly after birth. Guardian requires the first treatment three months prior to calving, and a booster five to seven weeks prior to calving.
Once calves are born, Marshall uses a bolus, First Defense. This supplements the immune protection with concentrated antibodies that go to the gut, bind and neutralize diarrhea-causing agents. It's then absorbed into the bloodstream for extended immune protection.
In addition to these steps, Marshall works to separate newborn calves by age, to the extent his facilities allow.
"When we're calving, once we get to around 25 calves, we'll move cows that haven't calved to fresh areas. This way we keep all the calves that are the same age together. If an outbreak occurs, it doesn't spread through the entire calf crop. Typically, the younger ones are more at risk."
What Marshall is describing is an adaptation of a method called "The Sandhills Calving System." "Here in Missouri, we don't have as much room, but the idea works the same," he said. Marshall's constraints include pastures that are an hour away from the main headquarters. Calving areas are located near feed and facilities.
"There is no perfect plan for calving, especially if you are worried about scours," Marshall said. "The most you can do is plan ahead and take preventative steps where possible. It's hard work, and more than a little stressful at times, but nothing comes for free."
What puts any cattle operation more at risk for scours? Craig Payne, University of Missouri Extension veterinarian, said there are several things his experience has shown him can add to the risk.
-- Concentration and Contamination. There's a higher risk of a scours outbreak when cattle are calving in concentrated areas. These areas become harder to keep clean the longer the herd stays there. Clean calving pastures are often key to reducing scours problems.
-- High Number of Heifers. It's possible more calves with scours come from heifers. This is an idea many researchers and veterinarians consider feasible for several reasons. Some heifers' colostrum quality/quantity may not be as good as older cows'. Heifers are more likely to have difficulty calving, another risk factor for the development of calf scours. And heifers, especially purchased replacement heifers, may be naive to pathogens on the new farm, so their colostrum may not yet include antibodies to those pathogens.
-- Spring Calving. Calves born into cold, wet or even snowy conditions may be slower to get up and nurse, compromising colostrum intake. This, along with the adverse environmental conditions, can be stressful for a calf and make it more susceptible to infection. When it's wet, cattle tend to congregate more around hay feeders and look for something dry to lay on. This will concentrate pathogens areas. Moving feeding areas around to reduce pathogen levels at calving time can offset this problem.
-- Cow Body Condition. At calving time, a cow should be at a 5 or 6 body condition to assure she has the ability and the energy to produce adequate quantity/quality colostrum. This also goes to the concept of fetal programming, where the nutritional status of a cow dictates the health of her offspring.
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