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Lymphocyte blastogenesis inhibition by milk whey as an indicator of mastitis
O Barta1, V D Barta, M V Crisman
1Virginia Polytechnic Institute, Blacksburg 24061.
Insights
Milk whey from cows with mastitis contains factors that inhibit lymphocyte DNA synthesis. This inhibitory activity increases with mastitis severity and is linked to milk somatic cell count and electrical conductivity.
Area of Science:
- Veterinary Immunology
- Bovine Mastitis Research
Background:
- Bovine mastitis significantly impacts dairy animal health and milk production.
- Understanding the immunological effects of mastitis is crucial for developing effective management strategies.
Purpose of the Study:
- To investigate the presence and characteristics of factors in milk whey that inhibit DNA synthesis in lymphocytes.
- To correlate this inhibitory activity with clinical mastitis severity and indirect indicators like somatic cell count (SCC), electrical conductivity, and bacterial load.
Main Methods:
- Collected milk whey samples from dairy cows with a history of mastitis.
- Assessed the ability of whey to inhibit DNA synthesis in cultured lymphocytes stimulated by mitogens (Concanavalin A, phytohemagglutinin P, pokeweed mitogen).
- Compared inhibitory activity with milk SCC, electrical conductivity, pH, and colony-forming bacterial counts.
Main Results:
- Milk whey exhibited significant inhibitory activity against DNA synthesis in lymphocytes.
- Inhibitory activity correlated positively with clinical mastitis severity and indirect indicators.
- Increased inhibition and electrical conductivity changes lagged behind somatic cell count increases.
- Whey from severely affected quarters (high SCC) demonstrated potent inhibition (69-100%) of lymphocyte DNA synthesis.
Conclusions:
- Milk whey from mastitic cows contains potent inhibitors of lymphocyte DNA synthesis.
- These inhibitors are linked to mastitis severity and may play a role in the cow's immune response.
- Bacterial numbers showed the weakest correlation with the observed inhibitory activity.
Abstract:
Sixty milk whey samples prepared from quarters of five cows with a history of mastitis were tested for their ability to inhibit DNA synthesis in mitogen-stimulated lymphocytes. The inhibitory activity was compared with milk SCC, electrical conductivity, pH, and the number of colony-forming bacteria in the milk. Milk whey contained factors that inhibited DNA synthesis in cultured lymphocytes. Inhibition of mitogen-induced DNA synthesis increased with the clinical severity of mastitis and with increased values of indirect indicators of mastitis. The increases in inhibition and electrical conductivity were delayed past the increases in SCC. Milk whey (10 microliters) from quarters with clinical mastitis and from quarters with SCC greater than 900,000 inhibited 96 to 100%, 84 to 100%, and 69 to 100% of DNA synthesis in 3-d cultures of lymphocytes stimulated with Concanavalin A, phytohemagglutinin P, and pokeweed mitogen, respectively. The numbers of colony-forming bacteria correlated least with the inhibitory activity.
