Mastitis Flashcards
Wholesome product
No adulteration/contamination
Drug residue issues
Welfare
Freedom from pain, injury, disease
Processor perspective
Number of bacteria impacts shelf life
Abx interfere with cultures
Mastitis changes milk composition and increases pH
Producers perspective - cost of mastitis
Lost milk production
Direct tx costs
Indirect cost of premature culling
Loss of quality bonuses
On farm
Cooled to 10c within 4hrs or less. 7c within 2hrs after completion of milking.
Traditional pasteurization
(72C) 161F for 15sec before rapid cooling
Destroy M. Tuberculosis, coxiella burnetti, brucella abortus
Refrigerated life of 2-3wks
Ultra pasteurization
> 280F for at least 2sec
Allows for extended shelf life under refrigerated (4-8wks)
Aseptic processing
Hold milk at 280F for at least 2sec
Can be stored unopened and unrefrigerated for long periods of time
Peracute mastitis
Sudden, severe
May include shock, septicemia, loss muscle coordination, cold extremities
Subclinical mastitis
Not detected visually Elevated SCC causes great economic loss Clinical and subclinical can become chronic Lose $1billion annually
Clinical mastitis
Summer in SE (heat stress, humidity)
Causes of mastitis
Invasion of microorganism through teat canal
Trauma or injury to udder
Chemical irritation
Cow defense against mastitis
Streak canal and muscle sphincter
Keratin plug, somatic cells
Ab and other soluble factors
Flushing action
Somatic cells
Primary defense once bacT breech streak canal
3 main types: epithelial cells, macrophages, PMNs
Indicates amount of inflammation
Factors driving SCC
Infection status, stage lactation, cow age, season of year, location, level of milk, time of collection
CMT
California mastitis test
Rapid, subjective for subclinical mastitis
Legal SCC limit in US
750,000/ml
Contagious pathogens
Strep agalactiae
Staph aureus
Mycoplasma species
Environmental pathogens
Strep species
Coliforms
Contagious pathogens
Cow to cow spread
Udder main source, spread at milking time
Presents as subclinical usually
Strep agalactiae
Gram + cocci. Only survives short periods in environment. Causes high SCC
Easiest organism to control, responds well to lactation and dry cow therapy. Post milk dipping reduces by >50%
Staph aureus
Gram + cocci. Very contagious. Source of infection: infected mammary glands, colonized teat ducts, infected teat lesions
Potentially body/udder skin. Usually presents as chronic subclinical. Can have severe clinical - gangrenous, fresh 1st lact. See blind quarters. Heifers prime source of infection, control flies
Cure rate poor with abx
Mycoplasma spp.
BacT with membrane, highly contagious. Economic impact. Frequently more than one quarte involved. Milk appears sandy or brownish. Often very high SCC. Can survive in semen. Shed intermittently. Once pos, always pos. direct plating on special media, limit is 100CFU. differentiate types by FA typing
When suspect mycoplasma problem
No response to tx and negative cultures
Spreads from one quarter to anothe
Clinical flare ups
Don’t wait for classic grainy appearance
Strep Uberis and dysgalactia
Environmental. Many new infections occur during 1st 2wks following dry off and last 2-3wks prior to calving.
Gram neg- e. coli
Highest incidence in early lactation
Seasonal. Most infections short duration.
CS: fever, shock, milk clots, watery, bloody
J5 vaccine -$60 return on investment
Klebsiella
Typically more severe than e. coli
More difficult to treat, green sawdust shavings
Management
Treatment Dry cow therapy- often most effective Mailing order- contagious last Culling Vaccination
Teat canal open/dilated
1/2 hr after mailing
Provide feed immediately after milking
Keratin teat plug
Absorbs bacT and shed at milking
Mastitis control program
- Clean environment 2. Proper nutrition 3. Proper maintenance of equipment 4. Proper pre milking prep. 5. Apply and remove machine properly 6. Post dip 7.tx and record cases 8. Routine surveillance 9. Segregation/culling 10. Dry off therapy
Predip contact time
45-60sec
Machine attached within
1-1.5min of priming
Why abx fail
Fail to reach site of infection
Resistance
BacT dormancy
Reinfection issues
No need to treat
Mycoplasma - doesn’t work
Sources of bacT in raw milk
From environment
Within udder
In milking system
Causes of high lpc- lab pasteurized count
Improper sanitation of equipment
Cause of high coli count
Milking wet cows
Pi - preliminary incubation count
Measure of raw milk keeping quality
Cause of high PI count
Improper sanitation of milking equipment before or after milking
