Even the best cowboy will tell you that identifying a sick calf is a subjective process. Whether in the feedyard, wheat pasture or backgrounding lot, the art of pulling “sicks” depends on a rider's ability and experience in spotting a sick animal before the disease process negatively affects it.

But, good riders are in short supply, and training inexperienced riders is costly. Plus, it's not uncommon for a cowboy to observe 8,000 head/day. With so many animals to monitor, accurately assessing the health of each is difficult.

Management over medicine

Innovative technology used to detect a calf's susceptibility to disease may be just what ranchers, pen riders and veterinarians need in a new era of strategic cattle management.

Animal Profiling International (API), Portland, OR, has introduced an animal performance index to assess the risk of bovine respiratory disease (BRD), or “shipping fever,” in cattle. Estimates indicate BRD costs more than $1 billion annually, while a recent U.S. cattle study found total mortality rates rose from 10 deaths/1,000 in 1994 to 17.5 deaths/1,000 in 2003 — a 75% increase. Driving the trend was increased mortality in feedlots caused by BRD (see chart below).

Bruce Hoffman, DVM and API president, says API's mission is to identify and commercialize the most promising risk-assessment technologies for improving animal health management. The initial focus is analyzing oxidative stress biomarkers for cattle, derived from a simple blood draw. API's proprietary algorithm assigns each animal an index value that is used to evaluate and manage cattle.

“Our analytical tools enable veterinarians and producers to manage cattle more effectively,” he says. “We offer cattlemen a ‘management over medicine’ technique for increasing industry profitability.”

Human studies link oxidative stress to immune system weakness, cardiac disease and inflammation (see page 70 sidebar). Like all infectious disease, BRD has an inflammatory component. API has bled more than 7,000 head of cattle in different U.S. environments to design and validate its performance index.

When a calf is stressed, its body secretes hormones that positively and negatively affect bodily functions, Hoffman explains. Stress makes the entire body more prone to infection by allowing disease organisms easier entry, and by disarming some important defense mechanisms. In addition, stressful events, such as weaning, shipping and dietary and environmental changes, elevate oxidative stress.

Stress and performance

Scientific values provided by API's performance index help producers better identify at-risk cattle, better target treatment costs and improve performance. Samples are analyzed and returned within 24 hours of being received at the API lab.

“The rancher, stocker or feeder uses the values drawn from the index to sort high- and low-risk animals,” Hoffman adds. “One can then adjust metaphylaxis programs and rations, as well as shipping and confinement strategies.” Metaphylaxis is the group treatment of high-risk cattle with antibiotics before clinical signs of illness are present.

API also offers a screening test for animals persistently infected (PI) with the bovine viral diarrhea virus. API uses pooling techniques, in addition to the antigen capture ELISA method. Whole blood, serum and skin (ear notch) are all appropriate to identify infected animals.

“Positive animals can be retested 30 days after the original test to assure the PI state,” Hoffman adds. He says the test is 100% sensitive in determining a PI animal.

“The tests fit our mission of using quantitative assessment to identify animals before they get sick,” says Ray Rogers, API chairman and CEO. “Our focus is to use our technologies to prevent unnecessarily treating animals. That's where losses really add up, when you consider treatment costs, reduced weight and carcass performance.”

Rogers and Hoffman say other benefits include an improved ability to select low-risk animals for antibiotic-free beef programs, greater feed efficiencies and improved carcass quality.

“We utilize API in our research field studies to get a more objective baseline of the cattle being enrolled in our studies,” says Shaun Sweiger, DVM, Edmond, OK. “Our industry continues to face increasing scrutiny of such practices as metaphylactic use of antibiotics, and we must continue to research and develop such technologies to help us better manage cattle in our care.”

As a vet, Hoffman says his experience indicates it's far superior to employ effective management to preempt the need for treatment. Yet, the combination of today's treatments and enhanced management techniques isn't getting the job done, and health losses continue to increase.

“Our goal is to increase accuracy by using quantitative data over subjective evaluation,” he says.

Incorporating ID

The newest addition to API's analytical system is the WRITETAG system, which is unique in that it reads and writes data to the ear tag, Rogers says.

Each animal carries its own data, instant traceability. The encrypted source information will only be read in the event of a foreign animal disease outbreak or on a need-to-know basis. All data is held in strict confidence.

The system consists of WRITETAG, a low-frequency button-type tag; and the WRITETAG Writer, an inexpensive device designed for the small producer to write source, age and antibiotic treatment to the ear tag, Hoffman says. There is no software or extra gadgets in the system.

He says the WRITETAG system was designed as a cost-effective approach to verifying source and age, and documenting treatments for validation in natural beef programs.

“The data will be on the tag when the animal arrives at the next location,” he says. “Our tags are readable with all full-duplex readers, but only our readers will read the data on the tag.”

API also will have software versions for cow-calf and grower/stocker/feeder operations, designed to write a complete health and performance history to the tag.

“The WRITETAG IntelliWriter will be able to read, write and store data for the animal's complete history,” Rogers adds. “It also will allow users to review an animal's history in the field by using the corresponding visual tag to access it.”

API also has a chute reader, and is adding other innovations to read multiple tags at greater distances.

Jim Coakley, Coleman Natural Foods vice president, Sterling, CO, likes the read/write ID system idea. In fact, his company is considering providing an incentive, possibly in rebate form, to producers who use API's ID system.

API's initial focus on cattle is based on its experience in the industry, Rogers says.

“In addition, globalization is driving the industry to individual ID systems that enable health information about a specific animal to be collected and retained,” he says. “The ability to evaluate cattle's health history and current status can improve the animal's profitability, and provide a higher quality product to consumers.”

To learn more, go to www.animalprofiling.com/, or phone 503/819-8873 or 406/282-7414.

Death due to BRD as percentage of total feedlot death
1994 52.1%
1995 55.4%
1996 55.4%
1997 59.6%
1998 57.0%
1999 61.5%
2000 62.5%
2001 64.0%
2002 62.5%
2003 67.1%
Source: Loneragan et al. JAVMA, 2001; 219:1122-7 (1994-1999) and Dargatz (USDA:APHIS:VS:CEAH; 2000-2003.

Oxidative stress unplugged

Oxidative stress contributes to inflammation, cardiac disease and immune-system weakness. It's been found that stressful events elevate oxidative stress, such as weaning, shipping, and other dietary and environmental changes.

Oxidative stress unfolds like this: During cells' energy-producing processes, the body continually metabolizes oxygen. As a result of this activity, highly reactive molecules, called reactive oxygen species (such as free radicals) are derived. Because these molecules have unpaired electrons in their structure, they're very unstable. While “searching” for an electron, the free radicals react with other molecules, causing oxidative damage, and massive cell damage to proteins, membranes and DNA.

Antioxidants produced by the body and supplied in the diet neutralize these free radicals. Under normal circumstances, the body maintains equilibrium between pro-oxidants (free radicals) and antioxidants. A disturbance in the system's equilibrium — where pro-oxidants outweigh antioxidants — causes the body to lose its ability to neutralize free radicals, resulting in oxidative stress.

Free radicals also can be produced by inflammatory response, stress and environmental insult. When the free radicals aren't neutralized and the cell damage isn't repaired, cell death occurs, leading to a higher propensity for disease.

Through the use of Animal Profiling International's oxidative stress biomarkers, oxidative stress levels can be gauged before or during stressful periods.

During stress periods, hormones are released that also produce free radicals. In turn, the liver must detoxify the hormones, resulting in more free radicals. The animal's body is unable to neutralize the new large quantity of free radicals that are damaging cells, making it possible for pathogens to invade and cause disease.