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97 Cards in this Set

  • Front
  • Back
What is mastitis?
Inflammation of the milk secreting tissues of the mammary gland caused by microbial infection of 1 or more quarters
Is mastitis a dz of humans?
Yes
What economic losses are caused by mastitis?
Decreased milk production
Milk dumped due to treatment
Veterinary and drug costs
Labor costs
Culling and death losses
Lost quality premiums
Bacteria that cause mastitis enter from where?
generally enter through the teat canal
What are the risk factors for mastitis?
-cow characteristics
-milking procedure
-milking machine
-environment
-infectious organisms
What is the first line of defense against bacteria in the mammary gland?
Teat canal
-epithelium
-keratin plug
-teat sphincter
-length/width of teat canal
-leucocytes in fore milk
After milking, the teat canal can remain open for 2 hours, what should you do with the cow during that time?
have her stand
What somatic cells are found in the healthy udder?
The mastitic udder?
Macrophages in healthy udder
Neutrophils in mastitic udder
What is the normal somatic cell count?
Normal somatic cell count < 100,000 cells/ml
Why do neutrophils struggle to exist in the mammary gland?
-Milk has lactose NOT glucose
-No energy source for PMNs
-Deficiency of opsonins and complement in milk
-Casein coats the outside of the neutrophil
-Loss of PMN pseudopods due to ingestion of fat
-Decrease in supply of hydrolytic enzymes within the PMN following ingestion of fat and casein
Immunoglobulins provide what defense to the udder?
-enables phagocytosis
-can prevent adherence of bacteria to epithelial cells
What role does lactoferrin play?
Prevents multiplication of iron-dependent bacteria
Which cytokines are defense mechanisms for the udder?
Interleukins
Interferons
Tissue Necrosis Factor
Colony Stimulating Factors
Why do most new cases of mastitis develop at or near the time of calving?
Lowered defenses
High circulating cortisol levels!!
Neutrophil function is depressed
Macrophages are not as efficient at phagocytosis
Milk leaking
Concurrent illness
LDA, metritis
Coliforms in calving area
Previous Staph
What are the signs of clinical mastitis?
Signs of infection
Udder shows signs of inflammation
Milk is abnormal
Flecks, gargot (clots), off color, bloody
What is a sign of subclinical mastitis?
No evidence of abnormality except milk positive on special tests
How does mastitis decrease milk production?
Decreases milk production by causing tissue damage, reduced lactose production and scar tissue formation in the udder
How does mastitis affect milk composition/quality?
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.
Bacteria, blood cells and enzymes
Proteolysis
Lipolysis and globule breakdown
Off flavors
What does a proper examination of the mammary gland include?
You have to visually examine it AND palpate the entire gland and associated lymph nodes
What are the cardinal signs of inflammation of the mammary gland?
Rubor
Calor
Tumor
Dolar
Loss of function
What changes do you look for when visually examinin the udder?
Loss of symmetry
External lesions
When palpating the udder, what changes do you look for?
Fibrosis
Enlarged lymph-nodes
Abscess
Hot, painful, swollen
Macroscopic changes in milk secretion include what?
Flakes
Clots
Gargot
Clumps
Watery
Bloody
What is gargot?
Flakes of fibrin, cells and calcium produce chunks
What stall side test can be used to check for mastitis?
CMT-checks for subclinical mastitis
What other dx test help monitor the herd for mastitis?
DHIA
SCC
Milk Cultures

Ultrasound!
Abscesses
Nonfunctional quarters
What is the basis for the CMT?
Cow side test
Alkyl arylsulfonate and bromcresol purple
Lysis cells and polymerizes DNA
Gel is formed by the DNA
More gel = more nucleated cells.
What conditions can affect the results of a CMT?
Colostrum
Late lactation (at dry off time)
Illness leading to abrupt decrease in milk
First strippings of milk from teat
Residual milk
Trauma to udder
What 2 types of milk samples can be collected for bacteriology testing?
-individual
-bulk tank
When do you perform an individual bacteriology collection/test
used to screen herd for infected cows
When do you perform a bulk tank bacteriology test?
Used to screen or monitor herd for contagious mastitis (Strep ag, Staph aureus, Mycoplasma)
90% of mastitis is caused by a contagious spread or by infection from the environment?
Contagious, animal to animal
By what methods is contagious mastitis spread?
Is spread from cow to cow, primarily during milking by milk-contaminated fomites at milking, sponge, milker's hands, milking machine
What are the BIG 2 organisms that are responsible for contagious mastitis?
Staphylococcus aureus, Streptococcus agalactia
What is meant by acute mastitis?
Rapid and severe onset
High temperature
Serious condition
What is meant by acute gangrenous mastitis?
Same onset as acute, but then mammary gland becomes cold and cow rapidly deteriorates
What is chronic mastitis?
Persistent subclinical form
Can chronic mastitis still affect production and become a problem?
yes
Bulk tank SCC >250,000
>15% of cows on DHIA have a linear score >4.5
>2% new clinical cases per month
What are the characteristics of Staph aureus?
Facultative anaerobic
Gram positive cocci
Grape-like clusters
“Golden” appearance
Coagulase positive
Staph aureus is the most important cause of mastitis, where does it live?
On the skin
(is drug resistant, highly invasive and host adapted)
Gangrenous mastitis from S aureus is more common in which type of cow?
First calf heifer
What is the pathogenesis of S aureus?
Colonize teat skin and enter through sphincter
Early lactation
Gangrenous mastitis in cows, goats sheep
Chronic infections are the rule
What is the end result of a S aureus infection?
Invades the milk producing tissues
Attaches to the alveoli tissue
Abscesses form
What are the clinical finding of a S aureus infection?
Initial systemic response
Subsequent relapses are mild
Milk is thin with yellow flakes/clumps
What is the number 1 way that S aureus is spread?
man, milking machine
How can Staph infections be prevented?
Pre & post milking teat dipping
Milkers wear gloves
Separate paper towel for each udder
Milk infected cows last
Dry cow treat all cows
Cull cows with long standing infections (chronic)
Screen replacements (home & purchase animals)
What are the characteristics of Streptococcus agalactia?
-beta hemolytic (wide area of hemolysis on blood agar)
Gram positive
Predominatly facultative anaerobic
Where does S agalactia live?
Obligate intramammary
Short life outside the gland
Which age of cows are more susceptible to S agalactia?
older
What is the pathogeneis of S agalactia?
Spread is cow to cow or fomite
Enters through teat sphincter
Colonizes teat skin
Inflammation occurs in 4-5 days
Fibrin clots can block ducts
What are the sources of S agalactia infection?
Major source is the infected cow
Injected into udder during milking
Contaminated floors and stalls
Newly purchased cows
Heifer calves suckling penmates
Milking personnel as carriers
Generally, does S agalactia produce clinical or subclinical mastitis?
generally non-clinical, but produces high somatic cell count (SCC) and reduces milk production.
What are the clinical findings of S agalactia infection?
Initially fever, depression,off feed
Subsequently mild episodes
Milk is thin with white flakes and clumps
Can S agalactia be treated?
Susceptible to penicillin
How can you prevent S agalactia infections?
Pre & post milking teat dipping
Separate paper towel
Milk infected cows last
Dry cow treat all cows
Screen replacements
How do you provide protection against S aureus to the herd?
Culture and treat all positive cases
Repeat in 30 days
Institute contagious mastitis control program
What makes Mycoplasma bovis difficult to deal with?
Between a bacteria and a virus
No cell wall so antibiotics are generally ineffective
Selective media needed
What changes does M bovis cause in milk?
Characterized by sandy granules and tan colored milk
How is M bovis spread?
Spread through contaminated antibiotics, syringes milking units, common cloths, etc. 
How do you know if a mastitis is caused by M bovis?
An increase in severe clinical mastitis cases that resist treatment, but with little other effect on the cow.
The involvement of more than one mammary quarter, sometimes all four.
A marked drop in the milk production of affected cows.
Abnormal udder secretions that may vary from watery milk with a few clots to a colostrum-like material. Chronically infected cows may show a tannish secretion with sandy or flaky sediments that resembles cooked cereal in a whey-like fluid. Udder secretions may become purulent and last for several weeks.
How do you treat a M bovis infection?
You don’t!
Cull the cow and get her off the farm ASAP!!
DO NOT feed Mycoplasma mastitis milk to calves!!!
How can mycoplasma be prevented?
Pre & post milking teat dipping
Milk infected cows last
Cull infected cows or segregate infected cows
Culture replacements (home & purchase animals)
Culture bulk tanks or know herd history
What signs are seen that should make you suspect M bovis in the herd?
Mastitis following respiratory problems in herd
2. Young calf joint swelling and lameness
3. Young calf head tilt - inner ear infections
4. New knee and hock swelling on cows
5. multiple quarters with clinical mastitis
What environmental organisms can cause mastitis?
Coliforms:
-e coli
-klebsiella
-enterobacter
all Gram neg
When does enivronmental mastitis occur?
Usually occurs periparturient
Late dry period
Early lactation
How does environmental mastitis occur?
Occurs because teat sphincter does not keep out fecal contaminants
Where in the environment can klebsiella be found?
Wood shavings- for bedding
What can happen to a cow with environmental mastitis?
Cow can spontaneously recover from infection

Cow can succumb to endotoxemia
What are the clinical signs of coliform mastitis?
Acute to subclinical infections
Yellow to watery secretion
Subnormal temperature
Quarter can be hard and swollen
Egg drop soup
E coli are fecal organisms, how does e coli spread?
Poor hygiene (not cow to cow)
Higher incidence in hot summer (July-Aug)
Does e coli produce acute or chronic mastitis?
Acute/toxic (15% will be severe & life threatening)
Rarely chronic (Klebsiella more common)
What is the pathogenesis of e coli mastitis?
Coliform bacteria do not adhere to the mammary epithelial cells
If the cow has a strong immune system, the bacteria can be eliminated quickly
-Coliform bacteria quickly multiply and die in the mammary gland
-Bacteremia develops – hematogenous spread of bacteria to lungs and heart may lead to pneumonia and vegetative endocarditis

These cows experience mild udder inflammation and temporary decrease in milk production
When neutrophil influx into the udder is delayed or if the PMNs are not fully functional, the bacteria quickly multiply and the cow becomes systemically ill
What are the clinical signs of endotoxemia?
Dehydration
Fever followed by subnormal temperature
Tachycardia
Tachypnea
Injected sclera
Rumen atony
Worse cases, death
Clin path will show what in a case of endotoxemia?
Severe neutropenia
Elevated fibrinogen
Azotemia
Hypocalcemia is common
How is e coli mastitis treated?
IMM antibiotics vs frequent stripping
Systemic antibiotics

Supportive care:
Fluids
NSAIDs
Calcium
Vitamin C??
Steroids??
How can e coli infections be prevented?
Clean & dry bedding
J-5 vaccination in dry period
Feed cows at milking (time for teat sphincter to close)
What are the clinical signs of a Klebseilla infection?
Similar to e coli:
Acute to subclinical infections
Yellow to watery secretion
Subnormal temperature
Quarter can be hard and swollen
Where in the environment if Klebsiella found?
Associated with soil contamination
Grows well in wood products
Switch bedding
Maintain high pH in bedding
What are some other environmental organisms that can cause mastitis?
Pseudomonas
Protheca
Yeasts
where are Pseudomonas,Protheca and
Yeasts found?
Pseudomonas:Contaminated water, pipes, heater, wash hoses, teat dip

Protheca:algae, wet soil mud

Yeasts:excessive abx tx, Contaminated infusions
How can environmental pathogens be controlled?
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)
What management steps can be taken to reduce exposure to environmental mastitis?
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
What types of tx are available for mastitis cows?
IMM Therapy
..Injection of antibiotics into udder
Systemic Therapy
..Antibiotics IV, IM, or SubQ
Supportive Therapy
..Remove toxins – Frequent milkout
..Treat dehydration, swelling and pain
...Know bug
Dry Cow Therapy
Larger dose, longer acting product
What are the 8 things to consider when developing a mastitis tx plan?
Consider the pathogen
Consider the cow’s history
Consider the severity
Consider the alternatives
Institute treatment promptly
Choose Appropriate Antibiotics
Realize the limitations of antimicrobial sensitivity testing
Consider the pharmaconkinetics and pharmacodynamics
What steps can be taken to prevent contagious mastitis?
Proper Milking Techniques
Predipping
Maintain milking equipment
Milk contagious cows last
What steps can be taken to prevent environmental mastitis?
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
when plating milk samples for bacteriology, what plate type should be used?
Selective agar tri-plate (Blood agar, TKT agar, MacConkey agar):
Which organism causes mastitis in beef and dairy heifers?
Staph aureus (caused by flies on the end of teats)
What are the primary pathogens of mastitis in sheep and goats?
Staph aureus
Mycoplasma
Rule out CAE/OPP
Is mastitis common in camelids?
No
What are the predisposing conditions of udder edema?
Genetics
Nutritional management
Obesity
Lack of exercise
What is udder edema?
Not usually painful and occurs when pitting edema develops symmetrically in the udder prior to parturition
Can become a chronic condition and persist throughout lactation
How do you tx udder edema?
Treatment should be initiated if swelling threatens the udder support apparatus, or if the edema interferes with the ability to milk the cow
Massage, repeated as often as possible, and hot compresses stimulate circulation and promote edema reduction
Diuretics
Corticosteroids
Reduce salt in diet
What is the cause of bloody milk?
Small vessels rupture as a result of trauma or in conjunction with udder edema
Milk appears light pink or brown
No treatment necessary
Occasionally severe mastitis will cause bloody milk – guarded prognosis
What is in colostrum?
Immunoglobulins
IgG1 is present in the highest concentration in colostrum and milk
IgG1 concentrations decrease in maternal plasma 2-3 weeks before calving; from this time until parturition, maximum concentrations of IgG1 are present in lacteal secretions
Ruminants are agammaglobulinemic at birth
Colostrum can be absorbed across the intestinal epithelium during the first 24 hours of life
What factors affect colostrum quality?
Older cows have higher IgG levels
High producing dairy cows can have lower quality colostrum
Leaking milk before parturition

The cow produces colostrum for 72 hours
Colostral IgG concentrations are highest at the first milking after parturition and quickly decrease
How do you tell good colostrum from bad?
Colostrometer
Measures the specific gravity
Not an actual measurement – can only determine poor quality from acceptable quality
Milk must be at room temperature for reading to be accurate