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Reducing Tetanus Risks in Livestock

Susan Kerr

WSU NW Regional Livestock and Dairy Extension Specialist

     There was a long discussion thread about tetanus on an e-mail list serve for cattle veterinarians recently—a producer in the Midwest had lost several steers to tetanus after castration banding. With calving, lambing, and kidding (and therefore castration) season well underway, it is a good time to review this important but preventable disease.

 

     Tetanus is caused by a very potent toxin from a spore-forming, oxygen-adverse bacterium called Clostridium tetani. It is present in mammalian intestinal tracts and most soils, especially those with a history of manure deposits. The bacterium produces spores which are extremely hardy in the environment. If spores enter an animal’s body such as through a contaminated wound or into compromised tissue where they can avoid exposure to oxygen, the spores can germinate into active bacteria. These bacteria produce toxins that are some of the most potent known to exist. They interfere with the neuromuscular junction by causing continual muscular contractions and blocking muscle relaxation.

 

     Sheep, goats and horses are particular susceptible to this disease. Cases are less common in pigs and cattle, and much less common in dogs, cats, but certainly occur. Regardless of species, the signs of tetanus are similar: generalized muscular contractions and rigidity, erect tail and ears, pronounced third eyelids, inability to eat or swallow, increased sensitivity to noise and other stimuli, inability to stand, seizures, difficulty breathing and eventual death without treatment.

 

     Once an animal shows signs of tetanus, the odds of positive response to treatment are low; very early intervention has the highest likelihood of success. A veterinarian should certainly be consulted for best treatment outcomes. Surgical removal of dead tissue, tetanus anti-toxin, anti-inflammatories, IV fluids, specific antibiotics, and prolonged nursing care may save some afflicted animals.

 

     Prevention is much less expensive and has a much higher rate of success, of course. Tetanus protection is included in many Clostridial vaccinations such as 7- and 8-way products and C-D-T (Clostridium perfringens types C and D and Tetanus). It is not present in all such vaccinations, so be sure to read the label and purchase an effective product for tetanus protection. Here is a typical recommended vaccination schedule:

     Why is tetanus a special concern at this time of year? Many livestock producers use elastic bands to dock tails (lambs) and castrate animals (calves, lambs, kids). These bands cut off the blood supply to tissues past the band (tail and scrotum); these tissues fall off about 2 weeks later. As mentioned, C. tetani thrives in environments without oxygen and such dead tissue is a good place for this bacterium to start growing if spores are present. In addition to castration, docking, and wounds, tetanus cases have been associated with retained placentas (dead tissue) and hoof trimming that draws blood, allowing entry of spores into poorly-oxygenated tissue. It is never wrong to give a tetanus toxoid booster if injury or another condition puts an animal at increased risk of tetanus.

 

The moral of the story: never forget tetanus. Keep animals well vaccinated, booster at times of increased risk, keep good vaccination records, and PLAN AHEAD so tetanus never rears its ugly head as an unwelcomed—and deadly—surprise.

 

Terms to Understand

  • Passive immunity: protection against disease-causing agents imparted from another source, such as colostral antibodies, anti-toxins, or plasma transfusions. The animal has done no work to achieve this protection. It is immediate but short-lasting.

 

  • Active immunity: protection against disease-causing agents imparted by exposure to the agent naturally or in vaccine form. The animal’s immune system has responded to the threat to achieve this protection. It is slow to develop but long-lasting. After an initial vaccination series, immune levels can be increased quickly with booster vaccinations.

 

  • Anti-toxin: a commercially-prepared substance specific against a particular disease-causing toxin, such as botulism, enterotoxemia, or tetanus toxin. It consists of anti-bodies harvested from the blood of animals vaccinated with a toxoid against the disease agent. It imparts immediate and specific passive protection after injection, but protection is short-lived.

 

  • Toxoid: a commercially-prepared vaccine against a specific toxin produced by disease-causing bacteria, used to stimulate the host’s active immune response. An initial dose and a booster 2 to 4 weeks later are usually required, with annual or twice-annual boosters. This response is slow to initialize but strong and long-lived.

 

For More Info

http://www.merckvetmanual.com/mvm/generalized_conditions/clostridial_diseases/tetanus.html

 

 

 

 

 

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