Zoetis has released new surveillance results which show that Mycoplasma bovis is becoming an increasingly significant pneumonia pathogen in cattle1.
In more than 2,500 samples submitted by vets for analysis during 2014, 45% were positive, compared with 41% in 2013.
According to Dr Tim Potter MRCVS from Westpoint Veterinary Group, Mycoplasma bovis has emerged as an important pathogen of calves worldwide2. He said: "It is associated with a number of clinical presentations including respiratory disease, otitis media and arthritis.
"The role of Mycoplasma bovis in pneumonia is well established and there are a number of reports in the literature of respiratory disease outbreaks where it was the predominant bacterium isolated. However, as with most causes of pneumonia, colonisation by Mycoplasma bovis alone is not always sufficient to cause disease and it may present in combination with other respiratory pathogens."
For other pathogens, the surveillance found 83% of samples positive for Para-influenza 3 virus (Pi3v), 76% Bovine Respiratory Syncytial virus (BRSv), 32% IBR, and 25% for BVD. Apart from BVD, which saw a three-point reduction from 28% the previous year - these show little change from 2013.
According to Zoetis vet Carolyn Hogan, in pneumonia outbreaks involving Mycoplasma bovis, many of the clinical signs are similar to those caused by other pneumonia pathogens: coughing, raised temperature, rapid breathing and lethargy.
She said: "This can make it difficult for farmers and vets alike to identify Mycoplasma bovis as a possible cause of disease based on clinical signs alone, unless calves are also showing some of the other distinguishing signs associated with Mycoplasma infection.
"These include ear infections, head shaking or tilting, and arthritis. Poor response to treatment, with resulting chronic respiratory cases, may also be suggestive of Mycoplasma infection. For a definitive diagnosis, of course, analysis of blood or respiratory tract mucous is required."
Whilst vaccination protection is available against the viruses (BRSv, Pi3v, BVD and IBR) and Mannheimia (Pasteurella) haemolytica, Carolyn points out that there is no ‘off the shelf’ vaccine available for Mycoplasma bovis. She adds that treatment can be challenging due to the insidious nature of disease, and lack of effectiveness of some antibiotics.
Once Mycoplasma bovis is present on a farm, Carolyn cautions that eradication can be very difficult. "It can be transmitted in milk from carrier cows, and in saliva among calves, particularly when multiple animals suckle the same teat feeders.
"Minimising this pathogen's impact on health and productivity relies on reducing its exposure to susceptible animals and maximising their resilience against it. For a comprehensive programme of control measures, farmers should consult their vet."
Carolyn suggests that such a programme is likely to include: testing the farm's Mycoplasma bovis status; effective biosecurity; not feeding infected milk; ample ventilation for adults and youngstock alike; rapid spotting of sick animals, isolation and vet-prescribed treatment; vigilance for poor response to treatment and development of chronic cases; vaccination against main viral pneumonia pathogens; and low stress through good stockmanship.
References
Photo: By Y tambe (Y tambe's file) [GFDL, CC-BY-SA-3.0 or CC BY-SA 2.5-2.0-1.0], via Wikimedia Commons
PS: Whilst you're here, take a moment to see our latest job opportunities for vets.