Therapeutic effects of lactation treatment of bovine subclinical Staphylococcus aureus mastitis with penicillin
Treatment of subclinical Staphylococcus aureus mastitis is often delayed to dry-off, increasing the risk for chronic infection. The aim was to evaluate cure after lactation treatment of subclinical mastitis caused by penicillin-susceptible S. aureus with penicillin. Ninety cows from seven herds were given either a combination of intramammary (IMM) benzylpenicillin and intramuscular (IM) penethamate hydroiodide, sole IMM benzylpenicillin or no treatment. Treatment efficacy was evaluated based on bacteriology on day 7, 14, 28 and 56 after treatment, daily milk yield and inline measurement of either composite somatic cell count (ICSCC), measured with Delaval Online Cell Counter (OCC) or Lactate Dehydrogenase (LDH) measured with DeLaval Herd Navigator®, until 56 days after treatment.