Gram-negative bacterial infections of the mammary gland in cows

Todhunter, D.A.; Smith, K.L.; Hogan, J.S.; Schoenberger, P.S.

Gram-negative bacterial infections of the mammary gland in cows

1991

Todhunter, D.A. | Smith, K.L. | Hogan, J.S. | Schoenberger, P.S.

Naturally acquired gram-negative bacterial intramammary infections (n = 160) were studied in 99 cows over a 2-year period. Escherichia coli, Klebsiella spp, Serratia spp, Enterobacter spp, and unidentified gram-negative bacteria were isolated from 28.8, 39.4, 9.4, 5.0, and 11.2%, respectively, of infected mammary glands. A majority (61%) of intramammary infections were first detected during the nonlactating period. Gram-negative bacteria isolated during the first half of the nonlactating period were predominantly Klebsiella spp, Serratia spp, and Enterobacter spp. Onset of E coli intramammary infections was more prevalent during the second half of the nonlactating period and during the first 7 days of lactation. The majority (59%) of infections were <28 days in duration, but Klebsiella spp and Serratia spp infections were of significantly (P <0.05) greater duration than infections with E coli. The greatest percentage (47%) of gram-negative bacterial intramammary infections were first detected during the summer.

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