Likelihood of New Infection Intensity of teat end exposure to pathogens (pathogen load) Likelihood of pathogens gaining entry to mammary gland Ability of pathogens to grow in mammary gland & survive host defense systems
Why New Infections Near Calving? Physiological stress associated with parturition Reduced concentration of nonspecific immune factors in secretions Edema & leaking of milk Components of colostrum that interfere with leukocyte function
Why New Infections at Beginning of Dry Period? Flushing of teat & ducts is terminated Increased udder pressure & leakage of milk Teat dipping & cleaning stopped Phagocyte function (immune cells) is impaired
Why Few New Infections During Middle of Dry Period? Low stress Decreased intramammary pressure Keratin plug Increased leukocyte concentration Increased concentrations of nonspecific immune factors (lactoferrin)
Exposure to Pathogens Contagious pathogens Reservoir - infected glands Milking equipment, hands, hygiene practices, teat conditions Environmental pathogens Exposure to teat surface is mostly between milkings
Control of Mastitis Teat dipping (post milking) Contagious pathogens mostly (50% reduction in new infections) Tested products only (Iodine or Chlorine based) Barrier dips Hazards/problems? Application methods?
Teat Dipping Techniques Cup Dipping Be sure to cover all the teat touched by the liner!!
Control of Mastitis Dry cow therapy Treat all cows/quarters Cures existing infections Decreases new infections at drying off (Strep. Ag. - not E. coli.) Does not impact new infections at calving Hazards/problems? Application methods?
Control of Mastitis Nutrition Vitamins (E is critical) Selenium (recommend.3 ppm) Keep cows standing after milking Feeding?
Control of Mastitis Vaccination Stimulate antibodies against mastitis Problem - many strains Coliform - J5 vaccines Reduces number of clinical events & severity (not fewer infections) Other vaccines (Staph. Aureus)
Mastitis Therapy Antibiotics 10-12 over the counter drugs 5-6 prescription drugs Extra-label use (need Rx) Careful with residues (withdrawl) Intramammary infusion or under skin
Mastitis Therapy - When & How to Use Subclinical mastitis (SCC or conductivity)? Clinical mastitis Know pathogens involved - critical Historical record is critical to success Severity is important
Mastitis Therapy - When & How to Use Coliform mastitis Acute or peracute - vet or intense treatment including fluid & anti- inflammatory Mild to moderate - oxytocin & milking Antibiotic therapy - not indicated Problems/issues?