Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10976183 | Journal of Dairy Science | 2013 | 7 Pages |
Abstract
We performed a comparative study on the development of mastitis induced by Mycoplasma arginini or Streptococcus dysgalactiae after challenging the cows. Mycoplasma arginini did not cause any clinical symptoms on its own, resulting in only a transient increase of somatic cell count (SCC; increase ranging from 0.5Â ÃÂ 106 to 0.8Â ÃÂ 106 cells/mL) and a slight decrease of milk production (10%) for 5 d. In contrast, Strep. dysgalactiae induced more severe clinical signs in animals and SCC increased to 1.60Â ÃÂ 106 to 2.11Â ÃÂ 106 cells/mL for 10 d. In addition, milk production decreased (22.9 to 27.0%) for 10 d. After 3Â mo (2Â mo after the first challenge), animals that were challenged previously with M. arginini were rechallenged with Strep. dysgalactiae. Severe clinical mastitis developed, with very high SCC (5.00Â ÃÂ 106 to 21.5Â ÃÂ 106 cells/mL), and a very significant reduction of milk production (28.6 to 68.7%), which lasted more than 4Â wk, was observed. The severe clinical mastitis developed not only in cows inoculated with Strep. dysgalactiae andM. arginini in the same udder quarter but also in cows infected in the quarter previously not challenged with mycoplasma. Cows challenged first with Strep. dysgalactiae and rechallenged with M. arginini 2Â mo later developed only slight changes in both SCC and milk production, similar to those when the cows were challenged with M. arginini alone. We conclude that M. arginini infection does not cause remarkable mastitis (characterized by decrease in milk production and increase of SCC) but it significantly predisposes animals to infection with Strep. dysgalactiae, leading to severe clinical mastitis.
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Authors
Laszlo Stipkovits, Maria Somogyi, Balazs Asvanyi, Agnes Toth, Susan Szathmary,