They've been around for years and have saved thousands of cattle. Used properly, they offer customized treatment at a reasonable cost. Used improperly, they may offer no help at all.

"They" are autogenous biologicals. They're defined by the American Veterinary Medical Association (AVMA) as vaccines, bacterins or toxoids prepared from cultures of microorganisms which are inactivated and non-toxic and provide a practitioner with a unique opportunity to control certain infectious diseases.

Though they may agree on this definition, not all animal health professionals are in agreement about the role of autogenous biologicals in any treatment regimen. Some rely on them. Others scourge them.

If your herd has a health problem that can't be cured by existing licensed products, a veterinarian can develop a biological product specifically for your herd. The veterinarian takes samples from an infected animal, uses the infectious agent and develops a biological that impacts the illness.

What They're For Primarily, autogenous biologicals can be developed to cure a problem in specific herds in certain geographic regions. For example, if you and your neighbors are experiencing the same problems in cattle and have tried everything possible, an autogenous biological may do the trick.

"There are a lot of factors involved in developing autogenous biologicals," says Mark Wood, DVM. He serves as director of scientific affairs for the Animal Health Institute.

"In addition to strain variations that are present, you have to consider management practices," Wood says. "These may include shipping, commingling and sick pen segregation. There may be management problems that need to be addressed as well as immunological criteria.

If vaccines aren't administered properly, they'll fail. Sick and/or stressed animals often don't have the immunological competence to elicit a protective response," Wood says.

According to USDA's Animal Plant Health Inspection Service (APHIS) Virus-Serum Toxic Act of 1985, these biologicals are to meet emergency conditions in limited markets or local situations. Only licensed veterinarians can legally prescribe autogenous products.

Autogenous Vs. Non-Autogenous While autogenous biologicals may be a godsend in many cases, they're not regularly licensed products.

"Autogenous products do have a streamlined licensing process," Wood says. "Pre-licensing efficacy and potency testing, and in some cases, host animal safety testing, aren't required. However, when an autogenous biological is needed within 72 hours or less, there isn't enough time to perform all those tests."

Safeguards "A producer can't assume that just because a product has a label produced by some company that the product will be effective," says Donald Sawyer, veterinarian and professor emeritus of Michigan State University and chairman of AVMA's Council on Biologic and Therapeutic Agents.

"Producers must become informed as to the efficacy and potency of the biological," he says. "And, neither may be verifiable because of the circumstances in which the biological was made available."

He adds that while an autogenous product may fit a specific occurrence, it's up to the producer to be sure he understands why it's applicable to his exact situation.