Bovine respiratory disease

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Bovine respiratory disease (BRD) - (Shipping fever/Pneumonic pasteurellosis) - is a well-recognised stress syndrome in cattle worldwide[1].

BRD is one of the most common causes of morbidity and mortality in housed cattle and is caused by a combination of stress and disease causing agents, including viruses and bacteria.

Environmental factors (eg, weaning, transport, commingling, crowding, dust, and inadequate ventilation) serve as stressors that adversely affect the immune and nonimmune defense mechanisms[2].

Causative infective agents include:

- Histophilus somni[3] (also causes Thromboembolic meningoencephalitis)
- Pasteurella multocida
- Mannheimia haemolytica (formerly Pasteurella haemolytica)
- Mycoplasma bovis and M. dispar[4]
- Infectious bovine rhinotracheitis
- Parainfluenze virus (PI3)
- Bovine respiratory syncytial virus
- BVD virus
- Adenovirus
- Rhinovirus
- Herpes virus I, type 2[5]
- Enterovirus
- Malignant catarrhal fever virus
- Reovirus

These viruses spread via nasal secretions and primarily affect young cattle, with calves aged 1 – 4 months being the most susceptible. Mannheimia haemolytica and Pasteurella multocida are often secondary bacterial invaders. M. haemolytica is frequently isolated from pneumonic lungs in cattle, and P. multocida secondary to other pathogens (viruses, bacteria, mycoplasma). These two bacteria are considered as part of the normal bacterial flora found in the upper respiratory tract of most cattle but are not considered as normal flora of the lungs.

Under conditions of impaired pulmonary defenses, a severe necrotizing fibrinous pleuropneumonia develops. Spread of these organisms is by direct contact, or by ingestion of feed and water contaminated by nasal and oral discharges from infected cattle.

Aside of infectious causes, stress and environmental factors such as weaning, temperature, stocking density, dust, humidity, transportation and inadequate nutrition are also important co-factors in development of disease[6].

Clinical signs

Clinical signs include nasal and eye discharges, coughing, fever, anorexia, depression, droopy ears and open mouthed breathing. Pneumonia associated with either M. haemolytica or P. multocida can progress very rapidly.

Diagnosis

Diagnosis is based on presenting clinical signs supportive by diagnostic tests such as blood tests, percutaneous lung biopsy[7], ultrasonography[8], ELISA and PCR[9].

Treatment

Treatment of acutely affected cattle involves supportive fluid and electrolyte therapy. Antimicrobial drugs may be beneficial. Enrofloxacin and ceftiofur have been shown to be beneficial for the treatment of relapse of undifferentiated fever/bovine respiratory disease in feedlot cattle[10]. Additional drugs such as Tulathromycin and Tilmicosin have also been reportedly effect in cattle[11].

Preventative measures in feedlot situations include vaccinating at risk cattle with IBR, PI3 and BVD viruses, avoiding co-mingling of cattle from different sources during the first week of introduction of new stock, arranging pens and feeders to keep new cattle close to the feed and water supplies. Overcrowding should be prevented as much as possible.

References

  1. Ellis JA (2001) The immunology of the bovine respiratory disease complex. Vet Clin North Am Food Anim Pract 17(3):535-550
  2. Merck Vet Manual
  3. Elswaifi SF et al (2012) The role of lipooligosaccharide phosphorylcholine in colonization and pathogenesis of Histophilus somni in cattle. Vet Res 43(1):49
  4. Pardon B et al (2011) Prevalence of respiratory pathogens in diseased, non-vaccinated, routinely medicated veal calves. Vet Rec 169(11):278
  5. Prysliak T et al (2011) Respiratory disease caused by Mycoplasma bovis is enhanced by exposure to bovine herpes virus 1 (BHV-1) but not to bovine viral diarrhea virus (BVDV) type 2. Can Vet J 52(11):1195-1202
  6. Snowder GD et al (2006) Bovine respiratory disease in feedlot cattle: environmental, genetic, and economic factors. J Anim Sci 84(8):1999-2008
  7. Burgess BA et al (2011) The development of a novel percutaneous lung biopsy procedure for use on feedlot steers. Can J Vet Res 75(4):254-260
  8. Abutarbush SM et al (2012) Evaluation of the diagnostic and prognostic utility of ultrasonography at first diagnosis of presumptive bovine respiratory disease. Can J Vet Res 76(1):23-32
  9. Thonur L et al (2012) One-step multiplex real time RT-PCR for the detection of bovine respiratory syncytial virus, bovine herpesvirus 1 and bovine parainfluenza virus 3. BMC Vet Res 8:37
  10. Abutarbush SM et al (2012) Comparison of enrofloxacin and ceftiofur sodium for the treatment of relapse of undifferentiated fever/bovine respiratory disease in feedlot cattle. Can Vet J 53(1):57-62
  11. Michael GB et al (2012) Increased MICs of gamithromycin and tildipirosin in the presence of the genes erm(42) and msr(E)-mph(E) for bovine Pasteurella multocida and Mannheimia haemolytica. J Antimicrob Chemother' 67(6):1555-1557