Increase of lactoferrin concentration in mastitic goat milk

Lactoferrin concentration (LFC) in normal and mastitic milk of dairy goats were examined. LFC in bulk milk collected from 70 dairy goat farms and individual milk samples from 10 goats with mastitis were measured by enzyme-linked immunosorbent assay (ELISA) and their reaction time in methylene blue reduction test (MBRT) monitored. Bulk milk samples were categorized into three grades, such as high, normal and low, based on the reaction time in MBRT. The mean LFC in milk that was considered high quality (167 mug/ml) was significantly lower than that of those graded as normal (218 mug/ml) and low quality (304 pglml), while mean LFC in mastitic milk was 587 mug/ml. The correlation coefficient between milk LFC and MBRT time was found to be -0.7. Three goats were inoculated with Staphylococcus aureus into one of their udder halves. The mean milk LFC was found to be significantly higher (1500 mug/ml) than the control (30 mug/ml). These findings suggest that milk LFC may be useful as an index for intramammary infection in goats.