Pasteurella (Madi)

Pasteurella Setswana name = Madi) is a type of bacterial that commonly infects the respiratory tract of calves causing bovine respiratory disease. Pasteurella multocida is one of the most common bacteria isolated from calves suffering from shipping fever pneumonia.Pasteurella is usually a secondary bacterial invader, meaning that a virus or some other disease first weakens the immune system thus allowing Pasteurella to invade. Pasteurella is found throughout the environment and within the upper respiratory tract of cattle, but it usually does not cause disease in otherwise healthy animals.


  • clinical signs of infection start with depression, and decreased appetite. This progresses to complete loss of appetite, lowered head and ears, mucopurulent nasal (containing mucus and pus) discharge and a high fever and labored breathing.
  • Breathing is painful for these animals and they will often show a moist cough, rapid shallow respiratory rate and reluctance to move around.
  • If the animal is not treated by this stage of infection, the lungs can become irreversibly damaged, and the calf will often die.


  • On physical exam, the above clinical signs will be noted. Auscultation of the cranioventral lung field often reveals increased bronchial sounds, crackles, and wheezes.
  • Necropsy of an affected animal will show small amounts of fibrin exudation, some thromboses, limited lung necrosis, and suppurative bronchitis and bronchiolitis.
  • A diagnosis of Pasteurellosis relies on bacterial culture. Given that pasteurella multocida is a normal inhabitant of the upper respiratory tract, it is helpful to collect bacterial culture samples from within the lung tissues of a dead calf being necropsied. Otherwise, bacterial culture samples can be collected via transtracheal wash, bronchoalveolar lavage, or tracheal swab.


  • The outcome of treatment depends significantly on the stage at which disease is detected. Early recognition of pasteurellosis is critical and is associated with a better outcome.
  • Antibiotic treatment is necessary to stop the progression of disease caused by bacterial invasion of the lungs. Bacterial culture and sensitivity can help select an appropriate antibiotic. Long-acting antibiotics have been developed specifically to treat bacterial pneumonia in cattle because it is very important that the antibiotic treatment continue beyond the point at which the animal has apparently recovered.


  • The most important measure in preventing pasteurellosis is preventing stress and viral disease associated with fever.
  • Providing adequate nutrition and internal parasite control,
  • Establishing an effective and early immunization program (preconditioning)
  • Maintaining biosecurity by minimizing exposure to diseased and unfamiliar cattle.
  • The calf’s immune system, when functioning properly can prevent most infection with Pasteurella multocida. There are some newer vaccines available that can help prevent disease. There vaccines include live bacterial cultures and subunits.
  • Vaccination should be done 3 weeks prior to shipping calves to a feedlot and in dairy cows, vaccination of the dam prior to calving can help increase antibodies within the colostrum.