Guardian Now Provides Industry’s Only Six-Month DOI for E. coli

August 25, 2009 07:00 PM

Roseland, N.J. — Intervet/Schering-Plough Animal Health announces USDA approval of an important label extension for its Guardian scours prevention vaccine. The new label approval affirms that Guardian provides six-month duration of immunity (DOI) for E. coli K99 protection. This positions Guardian as the only multivalent bacterial and viral combination scours vaccine with six-month DOI for E. coli—the longest proven DOI on the market.
"Scours is the primary cause of death in neonatal dairy calves,” says Dr. Kevin Hill, Technical Services Veterinarian for Intervet/Schering-Plough Animal Health. "And E. coli is one of the most lethal bacterial agents causing calf scours. The new Guardian six-month E. coli DOI claim gives dairy producers additional confidence in vaccination at initial dryoff (five to seven weeks before calving), reducing the endotoxin stacking concerns that occur when multiple vaccinations are given closer to freshening. Producers have solid evidence that shows Guardian will provide E. coli protection when given as early as six months prior to calving.”
Neonatal diarrhea—or scours—is a symptom of infectious viral, bacterial or parasitic intestinal infection and is documented as the most common cause of calf sickness and death in dairy herds (USDA: APHIS: Vs, CEAH, National Health Monitoring System). Escherichia coli bacteria—or E. coli—are ubiquitous and capable of causing severe diarrhea and death within the first week of a calf's life. Economic losses come not only from calf mortality and treatment costs, but also from losses in future growth and production.
Sound management practices, including vaccination and environmental management, as well as ensuring calves receive adequate colostrum within the first two to six hours of life, can greatly reduce the incidence of scours. Administering a scours vaccine, such as Guardian, to pregnant cows and heifers helps transfer scours protection to the calf via antibody-rich colostrum.
According to Dr. Hill, efforts to achieve the new Guardian six-month E. coli DOI claim were successful for two primary reasons: the advanced subunit E. coli technology and a unique sustained-release adjuvant. He explains: "The K99 E. coli antigen in scours vaccines stimulates the production of protective antibodies, which is what we want. However, the E. coli cell wall is a source of dangerous endotoxin (bacterial toxin). The new Guardian production process harvests only the K99 pili and eliminates most of the cell wall material, thus providing a clean, more concentrated level of the vital K99 antigen. Subunit technology reduces exposure to potentially dangerous sources of endotoxins that can lead to adverse reactions. In addition, subunit technology provides a strong and extremely targeted E. coli immune response.”
Dr. Hill says coupling the Guardian subunit technology with its smooth, water-in-oil adjuvant translates into a safe, targeted and long-lasting immune response.
"Traditionally, water-based adjuvants are less reactive and oil adjuvants are longer lasting. The custom formulated water-in-oil adjuvant in Guardian provides the best of both worlds. It is long lasting with low reactivity.”

Guardian is a broad-spectrum scours vaccine for use in healthy pregnant cows and heifers that protects against the most relevant viral and bacterial causes of scours. It is labeled as an aid in the prevention of neonatal calf diarrhea caused by enterotoxigenic E. coli pilus type K99, bovine Group A Serotype G6 rotaviruses, enterotoxemia caused by Clostridium perfringens types C and D and as an aid in the control of neonatal calf diarrhea caused by bovine coronaviruses. Guardian has no negative effect (compared to control animals) on milk production when given to lactating cows (Intervet/Schering-Plough Animal Health Technical Bulletin).
"The fight against the costly effects of calf scours continues, but dairy producers now have another tool in their scours-management toolbox,” says Dr. Hill. "The new six-month E. coli DOI is just one more way Intervet/Schering-Plough Animal Health is advancing dairy calf health and productivity.”
Producers are encouraged to work with their veterinarians to design a calf scours management program appropriate for their herds.
Guardian is available through veterinarians or animal-health suppliers. For more information about Guardian, or to learn more about Intervet/Schering-Plough Animal Health's full line of innovative, high-quality cattle health products, visit or

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