A Case-Control Study: Comparing the Effects on Calf Health After Use of A Commercially Available Mycoplasma bovis Vaccine in Dairy Herds in Scotland

Mycoplasma Bovis is a common cause of bovine pneumonia in calves. Treatment and control of the disease are challenging. Treatment can be ineffective, and control is hampered by a lack of a licensed vaccine in Europe. Graeme Fowlie at Meadows Vets Centre outlines the proof of concept for the vaccine’s commercial use in the UK. Further work on assessing the effect of this vaccine in UK cattle herds infected with M. Bovis respiratory disease is warranted.

Extract:

‘A Case-Control Study: Comparing the Effects on Calf Health After Use of A Commercially Available Mycoplasma bovis Vaccine in Dairy Herds in Scotland’

Mycoplasma bovis (M. bovis) is a significant bacterial pathogen of cattle with rising significance in the UK (APHA 2020, Burr 2018). It has recently been cited as the most commonly identified pathogen in bovine respiratory disease diagnoses (APHA 2020, SRUC 2019). Morbidity and mortality rates from pneumonia outbreaks in calves have been reported up to 74% and 30% respectively (Maunsell 2009, Mahmood and others 2017).

M. bovis infection can cause acute disease and create chronic carrier animals. Clinical signs are varied: pneumonia, septic arthritis, otitis media, mastitis and less commonly meningitis, caesar wound seromas, keratoconjunctivitis and subfertility (Calcutt and others 2018, Maunsell and others 2011, Nicholas 2011, Nicholas and others 2006). Dudek and others (2013) found M. bovis infection facilitated systemic distribution and the immune system became ineffective in clearing M. bovis from the host. M. bovis spread in an endemically infected herd can be via aerosol, colostrum or milk (Dudek 2020). Calves can be infected from a young age: in one study nasal swabs from calves and vaginal swabs from their dams found 40% were positive for M. bovis at 4 days of age, suggesting possible pre or peri-partum infection (Stipkovits and others 2001).

Treatment of M. bovis is unreliable, treatment failures are high and increasing antimicrobial resistance patterns have been documented over the last 30 years (Gautier-Bouchardon and others 2014). M. bovis has no cell wall rendering penicillins and cephalosporins ineffective and M. bovis also has natural resistance to other antibiotics including trimethoprim-sulphonamides (Lysnyansky and Ayling 2016). Confirmation of the ability of M. bovis to produce a biofilm helps explain the lack of response to antibiotics and the hosts’ immune system (McAuliffe and other 2006).

Bovine mycoplasmosis is a challenging disease to firstly identify and then control. Bacterial culture can be unreliable, time-consuming and be affected by faster growing polymicrobial infections resulting in poor bacterial recovery rates (Calcutt and others 2018).

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