Dynamics of lingual antimicrobial peptide, lactoferrin concentrations and lactoperoxidase activity in the milk of cows treated for clinical mastitis.

The aim of the present study was to examine changes in innate immune factors in the milk of mastitic dairy cows treated with antibiotics. Cows in the antibiotics group (n = 13) were infused into the mammary gland with cefazolin on the sixth day after mastitis was diagnosed (the day of the mastitis diagnosis = day -6). The control group (n = 12) was not treated. Milk samples were collected once every 2 days from days -6 to 12 and somatic cell count (SCC), lingual antimicrobial peptide (LAP), and lactoferrin (LF) concentrations and lactoperoxidase (LPO) activity were measured. SCC and LF concentrations in the antibiotics group markedly decreased after the antibiotic treatment. When cows in the antibiotics group were divided according to SCC on day 0, LAP concentrations and LPO activity in cows with a lower SCC on day 0 (<5 × 10(6) cell/mL) were significantly higher and lower than those in cows with a higher SCC, respectively. These results suggest that LF concentration decreased with decrease in SCC after treatment and that LAP concentration and LPO activity differed depending on the severity of mastitis. This is the first report to reveal the dynamics of innate immune factor in milk of cows treated for clinical mastitis.