Caused by microorganisms (usually bacteria) that invade the udder, multiply, and produce toxins that are harmful to the mammary gland

Transcription

1 MASTITIS PA R T 1

2 MASTITIS Mast = breast; itis = inflammation Inflammation of the mammary gland Caused by microorganisms (usually bacteria) that invade the udder, multiply, and produce toxins that are harmful to the mammary gland Induces elevated somatic cell counts (SCC)

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4 Pathogen Mastitis Environment Host

5 WHY IS MASTITIS IMPORTANT? Affects milk quality, which cannot be improved once it leaves the farm Decreases yield for entire lactation Expensive Painful Increases culling rate Potentially fatal

6 INITIATION OF INFLAMMATION Video: (don t worry about the product being advertised)

7 INFLAMMATION Symptoms of inflammation as we know it are the same in the udder Body's attempt at self-protection Attempting to remove harmful pathogens and begin healing process Body's white blood cells released into udder to protect it Release of chemicals increases blood flow to udder = redness and warmth Fluid leakage into the tissues = swelling

8 SOMATIC CELLS Somatic = body Suggested by Prescott & Breed in 1910 Thought milk cells were detached epithelial cells By late 1960 s, somatic cell count (SCC) was accepted terminology

9 Tight junction Blood capiliary

10 Bacteria in alveoli PMNs leaving capillary

11 PMNs pushing through tight junctions to fight bacteria

12 PMNs in milk eating bacteria Leaky tight junctions Blood components leaking into milk through leaky tight junctions = changes in milk composition during mastitis that looks more like blood composition!

13 DO ALL COWS HAVE SOMATIC CELLS IN THEIR MILK?

14 WHAT IS NORMAL SCC? Remember these cells are a PROTECTIVE mechanism and aren t solely recruited during an actual infection Often, they take care of pathogens before the cow actually has mastitis At cow level < 200,000 cells/ml At quarter level < 50,000 cells/ml The major factor affecting SCC is infection

15 CELL TYPES IN NORMAL MILK Cell type % cells (range) PMN 0 11 Macrophage Lymphocyte Epithelial (milk producing) 0-7 Lee et al., 1980

16 Mastitis resistance depends on rapid migration of blood neutrophils into the mammary gland J.L. Burton, 2000

17 SCC IS IMPORTANT TO MORE THAN JUST COWS Legal SCC limit in the U.S. is 750,000 cells/ml Legal SCC limit in the E.U. is 400,000 cells/ml Actual limit in both is 400,000 cells/ml Milk buyers won t buy loads over 400,000 anymore because that is what consumers want and that is all that is allowed to be exported into areas that have a lower limit

18 2014 STATE SCC DATA

19 Chemotactic agents attract PMN into tissues & milk!

20 MILK COMPOSITIONAL CHANGES DURING MASTITIS Increased SCC Na Cl Whey protein (e.g. serum albumin, Ig) Decreased Lactose Casein K α-lactalbumin

21 TYPES OF MASTITIS Two types: Subclinical no visible signs of disease, but SCC will be elevated and bacteria will be present Clinical visible signs of disease are present; from flakes or clots in milk to a very sick cow

22 COW RESPONSE - + Subclinical no symptoms increased SCC bacteria milk loss reduced quality compositional changes Clinical flakes/clots Possible: abnormal milk swelling pain/heat/ redness fever appetite loss depression, etc. Peracute most severe even death

23 CLINICAL MASTITIS DETECTION Physical changes/udder palpation Swelling Heat Redness Sensitivity

24 CLINICAL MASTITIS DETECTION Milk changes Stripping Strip cup

25 CLINICAL MASTITIS

26 CMT

27 WMT

28 MASTITIS DETECTION METHODS CMT WMT Indirectly measures SCC in milk. Bromocresol-purple-containing detergent used to break cell membrane of somatic cells, which releases nucleic acid to form a gel-like matrix with a viscosity proportional to the leukocyte number Advantages: Cost-effective, rapid, use-friendly, can be used on-farm Disadvantages: Low sensitivity and relatively difficult to fully interpret Similar to CMT, but amount of gel that forms is measured in millimeters that remains in a calibrated tube Advantages: Cost-effective, rapid, gives actual SCC Disadvantages: Not done on-farm, difficult to use and interpret (must establish conversion chart based on actual SCC)

29 MASTITIS DETECTION METHODS Electrical conductivity Measures increase in conductance in milk caused by Na, K, Ca, Mg, and Cl ions during mastitis Advantages: Can be used on-farm Disadvantages: Non-mastitis related variations in EC can present problems in detection Cultures Lab-based tests using selective culture to identify different microorganisms involved in causing mastitis Advantage: Identifies specific pathogen causing mastitis Disadvantage: Can t be used on-site (with exceptions) and waiting time is days

30 MASTITIS DETECTION METHODS ph test Rise in milk ph due to mastitis can be detected using bromothymol blue Advantages: User-friendly, cost-effective, rapid Disadvantages: Not very sensitive Enzymes Assays are used to detect enzymes (e.g. NAGase and LDH) Advantage: Rapid results Disadvantage: Might be lab-based

31 MASTITIS DETECTION METHODS Fossomatic SCC Uses optical fluorescence; ethidium bromide penetrates and intercalates with nuclear DNA, and fluorescent signal generated is used to estimate SCC in milk Advantages: rapid and automated Disadvantages: expensive and complex to use

32 MASTITIS DETECTION METHODS Portacheck Uses esterase-catalyzed enzymatic reaction to determine milk SCC Advantages: cost-effective, rapid, user-friendly, cow-side Disadvantage: Low sensitivity at low SCCs Qscout st=pl2vm-bb_ggvk62cxiql- ORdHptJspEEFK&index=39&nohtml5=False Advantages: On-farm (not cow-side), lots of information Disadvantages: Expensive, difficult to use and interpret, not yet proven

33 DMSCC Direct Microscopic SCC Actual SCC Laborious procedure Requires training

34 QUESTIONS?