Mastitis in Dairy Cattle

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Mastitis in Dairy Cattle

• AVS 346
• Dairy Cattle Technology

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Mastitis

• An inflammation of the milk secreting tissues of
  the udder, caused by microbial infections in one
  or more quarters.
• Disease of Humans
• Affects 25 to 30 percent of all quarters
• The most costly disease of dairy cattle
• 200 /cow/year
• 2 Billion annually

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Mastitis Affects on Profitability

• Decreased milk production
• 70 of total costs
• Not visible to producers
• Milk dumped due to treatment
• Veterinary and drug costs
• Labor costs
• Culling and death losses
• Lost quality premiums

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Determinants of Mastitis
Resistance, nutrition, stress
Host
Infectious Agent
Environment
Pathogenicity, virulence, number
Housing, equipment, hygiene, weather, bedding
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Mastitis Infection

• Almost always caused by bacteria that generally
  enter through the teat canal.
• Four ways for cow to get mastitis!!
• The environment inside the udder is warm and
  moist with plenty of available nutrients, so
  bacteria multiply rapidly.

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Mastitis Terminology

• Clinical Presence of clinical signs
• Signs of infection
• Udder shows signs of inflammation (Rewdness,
  swollen, tender, hard, etc.)
• Milk is abnormal
• Flecks, gargot (clots), off color, bloody
• Goal lt2 per month
• Subclinical
• No evidence of abnormality except milk positive
  on special tests.
• CMT, SCC, Sterile milk culture, etc.

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Mastitis in a Herd
Clinical
Subclinical
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Detecting Subclinical Mastitis

• Increased Somatic Cells
• Bulk Tank SCC
• DHI Individual Cow SCC
• Direct Count, spectroscopy
• CMT
• Sterile Milk Culture
• Find mastitis causing organisms
• Electrical Conductivity
• Antibody ELISA
• NAGase
• N-Acetyl-B-D-Glucosaminidase

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Mastitis Terminology

• Acute
• Rapid and severe onset
• High temperature
• Serious condition
• Chronic
• Persistent subclinical form

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Mastitis Affects on Milk Composition

• Milk Production Decreases milk production by
  causing tissue damage, reduced lactose production
  and scar tissue formation in the udder.
• Milk Quality and Composition
• Increasing somatic cell count
• Polymorphonuclear neutrophils
• Decreasing lactose, casein, and fat production,
• Increasing blood components such as Na, K, Cl,
  bicarbonate, IgG and serum albumin.
• Electrical potential disrupted
• Bacteria, blood cells and enzymes
• Proteolysis
• Lipolysis and globule breakdown
• Off flavors

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Effect of SC on Milk Composition
Source John C. Bruhn, Extension Food
Technologist, U.C.-Davis, 1983.
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Effect of SCC on Cheese Yield
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Types of Mastitis

• Contagious
• Environmental

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Contagious Mastitis

• Primary habitat bacteria live on/in the udder and
  teat lesions
• Poor survival of bacteria in the environment
• Is spread from cow to cow, primarily during
  milking by milk-contaminated fomites at milking,
  sponge, milker's hands, milking machine
• Staphylococcus aureus, Streptococcus agalactia,
  Mycoplasma bovis and sometimes streptococcus
  uberis are contagious mastitis causing organisms.
• Usually chronic, subclinical mastitis

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Test Dont Guess!!!
Know the bug your dealing with!!
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Streptococcus agalactiae

• Strep Ag
• Gram positive
• Inhabits ducts and cisterns
• Does not survive in environment
• Inflammation blocks duct
• Leads to decreased milk production, increased
  somatic cell count and involution
• Few enzymes/toxins produced
• Antibiotic sensitivity

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Strep Ag - Continued

• Common Old Form
• Still common in poorly managed herds
• Causes 20-40 subclinicals for each clinical
• Susceptible to penicillin
• Can eradicate from herd with Test Treat
  program
• Well managed herds have eradicated it
• Dry cow treatment highly effective
• Proper sanitation and milking procedures prevent
  cross infection

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Sources of Strep Ag

• Major source is the infected cow.
• Injected into udder during milking
• Squawking
• Contaminated floors and stalls
• Newly purchased cows
• Heifer calves suckling penmates.
• Milking personnel as carriers

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Staphylococcus aureus

• 1 cause of mastitis in US
• Many forms
• Acute, chronic, subclinical (chronic, subclinical
  predominates)
• Produces many enzymes/toxins (catalase,
  coagulase)
• Invasive-hyaluronidase
• Resists phagocytosis immune system
• Forms abscesses may result in fibrosis
• Facultative intracellular pathogen
• Decreased milk production and increased somatic
  cell count

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Staphylococcus aureus

• Antibiotic resistance resulting from genetic
  mutations
• Difficult to eliminate
• Some environmental survival
• Skin, bedding
• Transferred via milking machine and milker
• Hands - Gloves
• May be isolated from mammary gland of heifers
• Found in combination with other bugs
• Early detection critical to successful treatment

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Mycoplasma

• Between a bacteria and a virus
• Characterized by sandy granules and tan colored
  milk
• No cell wall so antibiotics are ineffective
• Control by biosecurity
• Spread through contaminated antibiotics, syringes
  milking units, common cloths, etc. 
• Teat dipping is a good preventative
• Isolation and culling
• Usually in well-managed herds
• NYS Study 10 of herds have infected cow
• Maine BT Study 2002 3 of herds

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Control of Contagious Mastitis

• Dip teats in germicide after pre and post milking
  
• Treat quarters with dry cow antibiotics at end of
  lactation
• Milking order or separate claw for infected cows
• Flush milk claws (hot water or germicide) after
  milking infected cows (backflushing)
• Individual cloth/paper towels to wash/dry teats
• Clean hands, latex gloves
• Culture new cow additions
• Cull persistently infected cows
• Minimize teat end lesions
• Dry treat heifers before calving

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Environment Mastitis

• Environment to cow
• Incidence increases as the incidence of
  contagious mastitis decreases
• Primary habitat of bacterial is in the
  environment (feces, soil, bedding, water)
• Environmental contact at milking time or between
  milkings

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Environmental Mastitis

• Organisms from the bedding, stalls, corrals, etc.
  gain entrance through fatigued teat canals after
  or during milking to cause infection.
• Streptococcus dysgalactia, Streptococcus uberus,
  and Coliform (E. coli, Klebsiella) are a few the
  organisms that live in the environment.

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Got Mastitis??
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Coliforms

• E. coli, Klebsiella spp., Enterobacter spp.,
  Citrobacter spp.
• Gram negative
• Feces, bedding, wet dirty udders
• Transient peracute/acute mastitis
• Endotoxin
• Very sick - death
• More prevalent in warm, wet weather

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Sources

• Infection occurs when contaminated material
  contacts and enters teat canal
• Infections occur at any stage
• Sediment from unclean surroundings, flank, and
  udder
• Manure
• Polluted water (barnyard)
• Unclean equipment
• Wet bedding, especially green sawdust
• Infected quarter of other cows

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Eschericha coli

• Clinical signs include
• Acute to subclinical infections
• Yellow to watery secretion
• Subnormal temperature
• Quarter can be hard and swollen
• Inhabitant of GI tract
• Wet milking
• Septic infusion into udder
• Antibiotics of little help
• Supportive therapy
• Fluids, steroids, antihistamines,
  antiprostaglandins

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Klebsiella

• Clinical signs similar to E. coli
• Acute to subclinical infections
• Yellow to watery secretion
• Subnormal temperature
• Quarter can be hard and swollen
• Associated with soil contamination
• Grows well in wood products
• Switch bedding
• Maintain high pH in bedding

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Streptococcus species

• Strep non-ag, Environmental streps
• ie. Strep uberis, dysgalactiae, bovis
• Inhabitants of GI tract
• Infection rates highest before calving
• Behave like traditional mastitis organisms with
  chronic infections and high SCCs
• Clinical signs
• Similar milk infections with clots and flakes
• Moderate swelling
• High SCC
• Only mastitis organisms that elevate bulk tank
  plate count
• Prevention
• Milking sanitation, milk clean dry teats,
  predipping, clean up environment of dry cows,
  switch to sand bedding.

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Other Staph Organisms

• CNS Coagulase Negative Staphylococcus
• Sometimes called Environmental Staphs
• Not all species live in the environment
• Many live on the skin and in the teat canal
• 20 of milk samples will be positive with no
  signs of mastitis
• May actually prevent other forms of mastitis
• Common in well managed herds
• 3-10 of clinical cases
• Clinical and subclinical infections
• More common in first lactation cows and in early
  lactation
• Heifers havent had dry treatment
• Up to 73 spontaneous cure rate
• Treatment not recommended
• Dry cow therapy, teat dipping and milking
  procedures important in prevention

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Other Environmental Organisms

• Pseudomonas
• Gram negative, ubiquitous
• Contaminated water, pipes, heater, wash hoses,
  teat dip
• Antibiotic resistance
• Protheca
• Algae
• Wet soil and mud
• Yeasts
• Excessive antibiotic therapy
• Contaminated infusions

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Control of Environmental Mastitis

• More difficult to control than the contagious
  pathogens
• Most are resistant to germicides in teat dip and
  antibiotics in dry cow therapy
• Key is to ID source and remove (bedding, ponds,
  mud)
• Clip or flame udders
• Milk only clean dry teats
• Clean parlor, stalls, bedding
• Barrier dips
• Predip teats with germicide before milking No
  water
• Keep cows standing after milking - feeding
• Sterile single-dose infusion products
• Sterile infusion techniques (alcohol swab)

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Teat Sealant
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Orbeseal
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Orbeseal data
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Timing of Infection
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Somatic Cell Counts - SCC

• Epithelial cells and white blood cells
• Changes with milk production, infection, age,
  stage. 
• Measures the level of udder stress/damage/irritati
  on
• Individual Cows
• Under 240,000 /ml uninfected
• Over 240,000 /ml considered infected
• Not a measure of  actual mastitis infection
• Do not treat based solely on SCC!
• Bulk Tank
• Legal limit 750,000/ml not very stringent
• Easy way to assess the mastitis level in a herd
• Excellent mastitis management tool
• Highest correlation with milk production of any
  DHIA measure
• SCC probably can't be too low
• Not the SCC but response to infection which is
  important

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Factors that Influence SCC

• Minor Factors
• Age of the cow
• Stage of lactation
• Season
• Stress on the gland
• Breed
• Genetics
• Milking fraction
• Major Factor
• Mastitis infection

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CMT
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Somatic Cell Score - SCS

• Log of the SCC
• Used on DHIA sheets
• Fewer digits
• SCC of 1,000,000 versus SCS of 6.4
• Starts at 12,500 equals SCS of 0
• Doubles from 0 to 1, 1 to 2, 2 to3 etc.
• SCS of 4 or greater Infected
• Corresponds better to lost milk production

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Milk Production Losses
Eberhardt, et. al. 1979
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Early Lactation Mastitis Increases DO
Schrick et al. 1999. NMC Proceedings. P.189-190
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Mastitis Treatment

• IMM Therapy
• Injection of antibiotics into udder
• Systemic Therapy
• Antibiotics IV or IM
• Supportive Therapy
• Remove toxins Frequent milkout
• Treat dehydration, swelling and pain
• Know bug
• Lactational Therapy
• Likelihood of success?
• Dry Cow Therapy
• Larger dose, longer acting product

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Mastitis Treatment

• IMM Therapy
• Probably treat more cows than we need to
• Use an approved product
• Use proper technique
• Have culture reports and sensitivities
• Make best guess on first drug
• Cow history, treatments and results
• Dont give up on a certain antibiotic, often
  response is seen with longer course of therapy
• Have a standard protocol

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Mastitis Treatment Protocols
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Supportive Treatment

• Treat the symptoms
• Pain, temperature, swelling, dehydration etc.
• Reduced risk of antibiotic residues
• Organic herds
• Oxytocin / Stripping
• Eliminates toxins and bacteria food
• Not effective against contagious bugs
• Aspirin, Antihistamines, Anti-inflammatory
• Fluids dehydration

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Mastitis Prevention

• Environmental
• Keep cows clean!
• Proper Bedding
• Clean and dry
• General farm housekeeping
• Manure, water, flies
• Udder flaming, tail docking
• Cow comfort Stalls
• Post dipping
• Barrier dips

• Contagious
• Proper Milking Techniques
• Procedures, training, monitoring
• Predipping
• Maintain milking equipment
• Milk contagious cows last

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Diagnosing a Herd Problem

• Bulk Tank SCC dairy plant
• ID Herd problem
• Individual SCCs
• ID Cows
• CMTs
• ID Cows
• Check reasons for culling
• Infected cows may be gone!
• Sterile Milk Culture
• ID bug
• Determine treatment and prevention procedures

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Flow of DHIA Data
DART, Raleigh, NC
USDA-AIPL Associations AI Studs
LOOP - Ithaca, NY
Supervisor Upload
Components Lab
Mail or Download
Data Milk Samples
Farm
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DHIA Individual Cow SCC

• Level of new infections
• Low (lt4) last month - high (gt4) this month
• Benchmark lt2 cows
• Level of chronic infections
• High last month - high this month
• Benchmark lt10 of cows
• First lactation animals affected
• When are infections happening?
• At calving? Later lactation

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Culling
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Graph of Previous SCS vs Current SCS
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Average SCS by Lactation
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Number of Cows in Herd with Score of 7-9
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Avg SCS Lactation1, DIM lt40
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SCS Throughout Lactation