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One Shot (Canada)

This page contains information on One Shot for veterinary use.
The information provided typically includes the following:
  • One Shot Indications
  • Warnings and cautions for One Shot
  • Direction and dosage information for One Shot

One Shot

This treatment applies to the following species:
Company: Zoetis

Mannheimia Haemolytica Bacterin-Toxoid

PRODUCT DESCRIPTION: One Shot is a bacterin-toxoid for vaccination of healthy cattle as an aid in preventing bovine pneumonia caused by Mannheimia haemolytica type A1. One Shot is an inactivated freeze-dried product prepared from whole cultures propagated to increase the production of leukotoxin and capsular and cell-associated antigens. A sterile diluent containing adjuvant to enhance the immune response is used to rehydrate the freeze-dried bacterin-toxoid.

DISEASE DESCRIPTION: Pneumonia caused by M. haemolytica type A1 has resulted in substantial economic losses in the cattle industry.1 The disease condition, known as shipping fever, often prevents optimal weight gain in infected cattle and may result in death. Clinical signs may include difficult breathing, nasal discharge, reduced feed intake, fever, and increased pulse rate.

M. haemolytica type A1, a normal constituent of the bovine nasopharynx, increases greatly in number when an animal undergoes stress (transport, change in climate, viral infections). This rapid increase in bacterial population adds to the deposition of organisms in the lungs. In the lung, M. haemolytica type A1 may grow rapidly and produce a leukotoxin which incapacitates leukocytes (alveolar macrophages and polymorphonuclear neutrophils).2 When the bacterium is engulfed by a weakened leukocyte, the leukocyte is unable to destroy the bacterium, allowing the bacterium to produce leukotoxin, which kills the leukocyte. As the leukocyte dies, it releases enzymes that add to the fibrinopurulent consolidation and local areas of necrosis characteristic of pneumonia caused by M. haemolytica type A1 (shipping fever).

SAFETY AND EFFICACY: One Shot is considered safe in cattle of all ages. Following vaccination, animals remained alert, and they exhibited no signs of pain or soreness.

The product was observed to cause moderate swelling at the injection site in some animals, primarily in dairy calves. Resolution occurred in most cases within 14-28 days; while in a few animals, small swelling was noticeable 60 days postvaccination.

Efficacy of One Shot was demonstrated in challenge-of-immunity studies. Cattle (400-550 lb) vaccinated with 1 dose of One Shot were subjected to severe experimental challenge at 2 weeks postvaccination with a heterologous strain of M. haemolytica type A1. Six days postchallenge, animals were necropsied and individual lungs were evaluated for lung damage and lesions characteristic of M. haemolytica type A1 infection. Subcutaneous vaccinates demonstrated statistically significant reduction in lung damage compared to placebo controls.

Directions For Use

1. General Directions: Vaccination of healthy cattle is recommended. Aseptically rehydrate the freeze-dried bacterin-toxoid with the accompanying adjuvant-containing sterile diluent, shake well, and administer 2 mL subcutaneously. In accordance with Beef Quality Assurance guidelines, this product should be administered subcutaneously. Healthy cattle should be vaccinated a minimum of 14 days prior to weaning, shipping, or exposure to stress or infectious conditions.

2. Primary Vaccination: Administer a single dose to healthy cattle. Only a single dose is necessary to confer active immunity. Good management practices support revaccination whenever subsequent stress or exposure is likely.

3. Good animal husbandry and herd health management practices should be employed.


1. Store at 2°-7°C. Prolonged exposure to higher temperatures may adversely affect potency. Do not freeze.

2. Use entire contents when first opened.

3. Sterilized syringes and needles should be used to administer this vaccine.

4. Do not vaccinate within 21 days before slaughter.

5. As with many vaccines, anaphylaxis may occur after use. Initial antidote of epinephrine is recommended and should be followed with appropriate supportive therapy.

6. This product has been shown to be efficacious in healthy animals. A protective immune response may not be elicited if animals are incubating an infectious disease, are malnourished or parasitized, are stressed due to shipment or environmental conditions, are otherwise immunocompromised, or the vaccine is not administered in accordance with label directions.


1. Martin S, Meek A, Davis D, et al: Factors associated with mortality and treatment costs in feedlot calves: The Bruce County Beef Project. Can J Comp Med 46:341-349, 1982.

2. Berggren K, Baluyut C, Simonson R, et al: Cytotoxic effects of Pasteurella haemolytica on bovine neutrophils. Am J Vet Res 42(8):1383-1388, 1981.

Technical inquiries should be directed to Zoetis Inc. Technical Services, (888) 963-8471 (USA), (800) 461-0917 (Canada).

For veterinary use only

U.S. Veterinary License No. 190

Zoetis Inc., Kalamazoo, MI 49007, USA


Presentation: Available in 10 dose and 50 dose vials.

CPN: 1198066.6

Order Desk:   800-663-8888
Technical Services Canada:   800-461-0917
Technical Services USA:   800-366-5288
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