Milk L-lactate concentration is increased during mastitis

Area of Science:

• Veterinary Medicine
• Animal Science
• Biochemistry

Background:

• Mastitis is a significant concern in dairy cattle, impacting milk quality and animal welfare.
• Accurate and early detection of mastitis is crucial for effective treatment and herd management.
• Current diagnostic methods may not always provide rapid or cost-effective detection of subclinical cases.

Purpose of the Study:

• To evaluate milk L-lactate as a potential biomarker for mastitis in cattle.
• To correlate milk L-lactate levels with clinical and subclinical mastitis indicators like somatic cell count (SCC).
• To assess L-lactate changes in milk during different stages of lactation and infection.

Main Methods:

• Experimental induction of mastitis in cattle using Streptococcus uberis.
• Collection of foremilk samples from control and infected quarters for L-lactate and SCC analysis.
• Analysis of milk samples from a larger cohort of dairy cows with known mastitis cases on commercial farms.

Main Results:

• Milk L-lactate increased significantly (over 30-fold) in quarters with clinical mastitis, reaching 3.3 mM, alongside a rise in SCC to 1x10(7) cells/ml.
• Subclinical mastitis cases showed elevated milk lactate (0.7-1.5 mM) compared to control quarters (<0.1 mM), with SCCs ranging from 1.5x10(6) to 1x10(7) cells/ml.
• In commercial herds, L-lactate concentrations exceeded 2.5 mM in infected quarters, correlating with SCC levels, and were elevated postpartum, declining in early lactation.

Conclusions:

• Milk L-lactate is a promising indicator for both clinical and subclinical mastitis in dairy cows.
• The level of milk L-lactate response is closely related to the severity of infection and its impact on SCC.
• Further research could validate L-lactate as a routine diagnostic tool for mastitis management.