Identification of subclinical mastitis caused by Mycoplasma spp. from screenings of bulk tanks

S.F Joaquim,A Salina,H Langoni,F.F Guimarães,E.N Gomes,N.B Junqueira

doi:10.1590/1678-4162-9982

Abstract

ABSTRACT Mastitis caused by Mycoplasma spp., regardless of species, are considered highly contagious pathogens and, usually was not responsive to antimicrobial therapy. Five dairy herds, comprising 489 animals and 1,956 mammary glands, were used in this study. Milk samples were obtained from bulk tanks and subjected to polymerase chain reaction (PCR) for the identification of Mollicutes, Mycoplasma spp., and Mycoplasma bovis. Moreover, individual samples from cases of clinical and subclinical mastitis in quarters of the dairy herds’ animals that yielded a positive PCR upon bulk tank analysis were subjected to molecular analysis. Only one bulk tank was positive for class Mollicutes by PCR. All positive samples classified as mastitis teats had their DNA extracted and tested by PCR for both class Mollicutes and M. bovis. Of these, two (2.08%) were positive for Mycoplasma genus, although none was positive for M. bovis. This result suggests that the PCR of bulk tanks is a viable tool in monitoring and preventing mastitis infections caused by Mycoplasma spp.

Highlights

Mycoplasma spp. are considered highly contagious pathogens that cause bovine mastitis
Among the species of Mycoplasma, M. bovis is responsible for most mastitis outbreaks in dairy herds
Duplicate milk samples were aseptically collected from all mammary glands that tested positive on the screening tests for microbiological examination

Summary

Introduction

Mycoplasma spp. are considered highly contagious pathogens that cause bovine mastitis. The transmission of these pathogens occurs primarily during the milking period (Fox and Gay, 1993). These microorganisms are considered a worldwide problem (House et al, 2011). Among the species of Mycoplasma, M. bovis is responsible for most mastitis outbreaks in dairy herds. Mastitis caused by Mycoplasma spp., regardless of the specific species, usually is not responsive to treatment with antibiotics (Owens and Nipper, 2008). Being a highly contagious microorganism, Mycoplasma spp. can be disseminated as an aerosol or through secretions by animals with respiratory and genital disorders and during milking. The milk obtained from an animal with Mycoplasma spp. mastitis may be brownish to brown and, when allowed to settle, can have the appearance of sandy granules (Kirk et al, 1994)

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Conclusion