Mastitis Flashcards
1
Q
How does mastitis cause money loss?
A
- decreased milk production
- costs associated with clinical disease
- increased SCC
2
Q
What is somatic cell count?
A
indicator of mammary gland inflammation
linked to decreased milk shelf life and cheese yeld
3
Q
What is the regulatory limit of SCC in canada?
A
400 000 cells/ml
4
Q
What is the limit of bacteria in canada?
A
50 000 bacteria/ml
5
Q
What are the clinical signs of mastitis?
A
mild: abnormal milk, normal gland, systemically healthy
moderate: abnormal milk, abnormal gland, systemically healthy
severe: abnormal milk and gland, systemically sick
subclinical: increased SCC, destruction of alveoli and ducts, decreased production long term
6
Q
What are the two groups of mastitis pathogens?
A
contagious, environmental
7
Q
What is the reservoir of contagious pathogens?
A
mammary gland
8
Q
When are contagious pathgens transmitted?
A
at milking
9
Q
What are contagious pathogens?
A
S. aureus, s agalactiae, mycoplasma, corynebacterium bovis
10
Q
What is the reservour for environmental pathogens?gens?
A
environment
11
Q
What is the transmission of environmental path
A
between milkings
12
Q
What are environmental pathogens?
A
e. coli, s uberis, other coliforms, pseudomonas
13
Q
What are opportunistsi?
A
s. dysgalatiae
coagulase negative staph
14
Q
What is the prevalence of pathogens?
A
s. aureus most common isolated
e. coli
s. uberis
coagulase negative staph
15
Q
What are the features of s. aureus?
A
- most common contagious pathogen
- primarily subclinical (some clinical episodes)
- fluctuating scc and bacterial shedding
- gram positive coccus, coagulase and catalase positive; frequently hemolytic
16
Q
What are the characteristics of strep agalactiae?
A
very RARE as it is very sensitive for antibiotics
obligate udder pathogen
subclinical mastitis with periodic flareups
gram positive coccus
catalase negative
17
Q
What are the features of mycoplasma?
A
- severe clinical mastitis
- agalactia for rest of lactation
- primarily contagious
- some environmental reservoirs exsit
- young and mature asymptomatic carriers (calves)
18
Q
What are the features of clinical disease of mycoplasma?
A
the quarter stops producing milk for rest of lactation
19
Q
How can mycoplasma access the udder?
A
systemically (other body sites are affected)
20
Q
How many species of mycoplasma are there?
A
at least 5
21
Q
why should you inform lab you are worried about myoplasma?
A
because very slow
22
Q
What are features of corynebacterium bovis?
A
controlled by teat dip
primarily colonizes teat canal
23
Q
What are features of prevention and control of mastitis?
A
a. decrease exposure
b. increase resistance
5 point plan
1. post-milking teat disinfection
2. blanket dry cow therapy
3. clinical mastitis therapy during lactation
4. proper milking machine maintenance
5. cull chronically infected cattle
24
Q
What is the 5 point plan for mastitis prevention? (will ask this question)
A
- post-milking teat disinfection
- blanket dry cow therapy
- clinical mastitis therapy duing lactation
- proper millking machine maintenance
- cull chronically infected cattle
25
What is the most important mastitis prevention step?
post milking teat infection
26
What are the features of post-milking teat dinsifection?
```
1. decreases incidence of new IMI by 50-90%
iodine
chlorhexidine
organic acids + emolients-
quarternary ammonium
sodium hypochlorite
```
27
what is the problem with quaternary ammonium?
inactivated by organic material
28
What is a good feature of chlorhexidine?
it works in presence of organic material
29
What is the benefit of blanket dry cow therapy?
eliminates infection
| prevents infection
30
Is there a treatment for mycoplasma mastitis?
no
31
What are the steps in machine maintenance?
1. daily equipment inspection
2. regular service and parts replacement
3. complete machine evaluation (once a year)
32
What is a chronically infected cow?
1. repeated clinical episodes
2. repeated positive milk cultures
3. high chronic scc
33
What is the commercial vaccine for staph aureus, e. coli, coagulase negatieve staph?
TOPVAC
34
How long is the meat withdrawal for TOPVAC
60d
35
Why don't contagous mastitis vaccines work?
clearance of mastitis pathogens dependent on presence of sufficient neutrophils
every contagious
high neutrophils = mastitis
mastitis vaccine has to cause mastitis
36
What is therapeutic cessation of lactation?
infuse udder with povidone-iodine
chlorhexidine
welfare issue!
withhold period not established
37
Why is it not that useful having cow segregation for separating s. aureus carriers?
hard to ID all animals
38
What is control measures for mycoplasma?
remove from herd, segregate/milk last
take care when purchasing animals
prevent spread n milking parlour
39
What are the features of e. coli mastitis?
1. primarily clinica, fatal mastitis, local clinical signs
low prevalence
short duration of infection
50%
40
What are other causes of coliforms besides e coli?
```
klebsiella
enterobacter aerogenes
serratia
pseudomonas
proteus
```
41
What is kelbisiella traditionally associated with?
sawdust bedding
poor environmental management--standing water, poor cleanliness scores
80% of cattle shed klebsiella in feces
42
What are the cure rates for klebsiella?
poor cure rates in response to treatment
infections last for long periods
may be subclinical
43
Features of peracute coliform mastitis?
1. highly severe disease, high case fatality rates
2. quarter not always as swollen and warm as expected!!!!!
3. rapid course of disease--milk can go from normal to serum over course of an 1hr. Get sick very quicklyt
44
If an animal overcomes peracute coliform mastitis what are the consequences? (prognosis)
1. survival (>50%)
2. return to production (can be questionable)
3. side effects of recumbency
45
What is treatment of peracute coliform mastitis?
1. supportive care (fluid and electrolytes, management of recumbency)
2. appropriate antimicrobial and anti-inflammatory therapy
46
Why are antimicrobials in coliform mastitis contriversial
1. endotoxin causes disease
2. clinical signs after peak bacteria!!!--bacterial death--endotoxin
3. most forms self-limiting
4. endotoxin release
47
Do treatment trials show benefit of antimicrobials in coliform mastitis
no. esp with long term productivity. cost vs treatment efficacy?
48
What antimicrobial may be effective for coliform mastitis?
ceftiofur (but should we be treating anyway?) Have to manage the effect of a bunch of endotoxin being released into the cow
49
What are treatments for coliform besides antimicrobials?
maybe oxytoxin and milking frequently? no benefit likely
fluid and electrolyte therapy--peracute mastitis (hypocalcemic, hypochloric, hypertonic saline) 4mL/kg f can get oral fluids in them after
anti-inflammatories--meloxicam labelled for this. flunixin, ketoprofen, counteract effects of endotoxin. not directly endotoxin
50
How do you control coliform mastitis?
1. contact between udder and environment
2. environmental cleanliness is key
3. focus on EARLY DRY--still secrete milk not getting rid of it and transition periods--immunocompromized
4. premilkinng teat disinfection may play a role
5. other control measures: diet, vaccination
51
What are diet modifications used to reduce severity and duration of coliform mastitis?
Vit E or selenium
| copper supplementation also decreases duration
52
What are vaccines for coliform mastitis?
commercial vaccines based on J5 strain (mutant e coli that does not have O side chains--endotoxin--cause peracute signs; also means it is genus specific level so good cross protection)
systemic immunization
not preventing infection, just prevent severe clinical disease
53
What is the efficacy of TopVac? (coliform mastitis)
did not prevent clinical disease
54
Does the Jvac work for coliform mastitis?
yes prevents clinical dz
55
What are the features of streptococcus uberus dz?
1. clinical and subclinical disease
2. problem in low SCC herds
3. permanent colonization
4. straw bedding or pasture housing=major risk factors
5. gram positive, catalase negative coccus
6. 2nd most commonly isolated environmental pathogen
56
How do you treat environmental strep?
susceptible in vitro to antimicrobials
clinical cases respond well to antimicrobials
subclin cases in late lactation can wait until dry off
cures in 1st 100 days of lactation--economic benefits
oxytocin and frequent milk out actually cause relapses, decreased cure rates--teat end damage?
57
How do you control environmental streptococci?
```
minimize exposure of teat ends
dry sand is best bedding option
sand not good for alley scrapers
pre-milking teat disinfection
dry cow antimicrobials--more effective against environmental strep or coliforms
```
58
What are the features of opportunist pathogens?
1. may behave as both contagious and environmental pathogens
2. strep dysgalactiae
3. coagulase-negative staph
59
What are the features of strep dysgalactiae?
1. clin and subclin dz
2. usually environmental
3. can become permanently colonized
4. risk factors straw or pasture
5. treatment strategies similar as S. uberus
6. gram positive catalase negative coccus
60
What are the features of caogulase negative staph?
1. historically incidental
2. reservoir skin microflora
3. may increase milk production, may be related to prolactin; may decrease milk production
4. should evalute the species separately! not lump them together
61
What is a way that s. aureus can shield itself from antibiotics?
can form microabscesses
62
How are coagulase negative staph controlled?
1. depends on reservoir!
| 2. focus on the milking system but consider that could be environmental pathogen
63
What are minor mastitis pathogens?
1. tueperella pyogenes
2. pasteurella
3. nocardia
4. mycobacteria
5. bacillus
6. serratia
7. listeria monocytogenes
64
What does trueperella pyogenes cause?
1. sporat episodes of suppurative mastitis
2. "summer mastitis"
3. common on pasture
65
What are the bacteria involved with summer mastitis?
1. trueperella pyogenes as primary pathogenes
| 2. secondary anaerobic infection: peptostreptococcus indolicus, S. dysgalactiae
66
What is the prognosis for summer mastitis?
poor
67
What fly transmits summer mastitis?
hydrotoea irritans
68
What are the features of pasteurella mastitis?
1. more common in small ruminants
2. sporatic dz
3. toxemia, recumbency, swllen udder, watery red-tinged milk
4. susceptible to tetracclines
69
What are the features of nocardia mastitis?
1. uncommon sporadic dz
2. mastitis is either acute or subacute or granulomatous!
3. extensive tissue damage, udder will be fibrotic after infection!! big tissue damage!
4. common soil contaminant
5. chlorhexidine teat dips ineffective
6. doesn't respond well to antimicrobials
70
What are the features of tuberculous mastitis (mycobacterium bovis)
1. induration and hypertrophy of udder
2. large supramammary lymph nodes
3. administratrion of oil-based intrammmarmy infusions
4. hypertrophy of quarter
5. no effective treatment
6. reportable dz
7. call CFIA district vet
71
What are the features of bacillus mastitis?
if see in a milk culture without appropriate clinical signs then likely a skin contaminant!
The clinical signs are acute haemorrhagic mastitis--then start think that is real
peracute to acute dz
seen as contamination following teat injuries and surgery
contaminated dry cow therapy
broad specturm antimicrobials for treatment and supportive care
72
What are the features of serratia mastitis?
is a coliform but wimpy causing
mild chronic swelling of udder
periodic apperaance of clots in milk
responds to antimicrobial treatment
73
What are the features of listeria monoctogenes?
1. major zoonotic implicaions
2. subclin mastitis
3. very high SCC
4. generally resistant to penicillins
74
What are algaes that could cause mastitis?
prototheca trispora
P zopfii
chronic mastitis
induration of affected quarter etc
75
How do you investigate mastitis problems?
1. problem oriented approach
2. signalment (size of farm, breed)
3. history
4. physical exam
5. define problem, further testing
76
What are methods of diagnostics for mastitis?
1. SCC vs etiological agent
2. milk cultures (new culture technologies, bulk tank sampling)
3. ELISA
4. PCR
5. cow-side systems
6. in-line diagnosis
77
What are the features of california mastitis test
1. detergent reacts with DNA as a proxy for WBC
2. Sensitivity and Specificity approximately 0.6 but very poor correlation. just look for reaction or not
3. might be useful in screening animals--negative predictive value
78
What are the features of the somatic cell SCC test?
1. add reagent to milk, precipitation occurs
2. read SCC based on liquid remaining
3. manufacturer claims agreement with SCC of 90%
4. no peer reviewed studies
79
What are the features of milk culture for checking of mastitis?
1. plate sample on blood agar
2. incubate for up to 48hr at 37 degrees
3. freezing samples may enhance bacterial recovery--e.g. staph aureus like to live in cells--if milk is fresh, intracellular bacteria does not touch agar, does not grow. if freeze thaw then let staph aureus out.
4. be aware of cyclical shedding
5. ~30% of clinical isolates may be culture negative
6. special conditions required to grow mycoplasma spp
80
What are the features of petrifilm?
3M microbiology
on farm milk culture system
sample ready selective media
81
What are features of bulk tank cultures?
1. samples entire herd AND milk system
2. standard plate count
3. coliform count--usually from maure contamination
4. laboratory pasteurized count
5. mycoplasma count
82
What are the features of PCR?
1. speed, culture negative mastitis cases
2. CanWest DHI, pathoproof mastitis PCR assay
3. only 2 pathogens IDed--staph aureus, strep agalactiae, mycoplasma, proteus
4. bulk tank? usefulness?
5. samples often collected nonaseptically--e.g. DHI sampler, cow coming in could contaminate every next cow?
83
What is in-line diagnosis?
in automatic miknig systems
1. eletrical conductivity--not that good
2. impedance spectrometry--better--doesn't tell if clinical or not
3. lactate dehydrogenase part of herd navigator system--doesn't tell if clinical or not
84
What causes the highest prevalence of clinical disease in sheep and goats?
s. aureus
85
What is more common subclinically in sheep and goat mastitis
coagulase negative staph
86
Intramammary infection is more common in who?
goats more than sheep
87
What are etiologies of mastitis that are more common in small ruminants?
listeria
salmonela
lentiviruses
mycoplasma
88
What are contagious etiologies of mastitis in sheep and goasts?
```
s aureus
CNS
s agalactiae
t pyogenes
m haemolyticsa
```
89
what are environmental etiologies of mastitis in sheep and goats?
enterobacter
enterococci
pseudomonas
90
Why is CMT not useful in small ruminants?
because the SCC is higher in small ruminants than in cattle
91
What may increase SCC in sheep and goats?
lentiviruses
92
Is SCC highier in sheep or goats?
goats
93
Why might one be reluctant to treat mastitis in sheep and goats?
cost of treatment may be similar to cost of replacement
| little data on efficay of treatment
94
Why is there more selective dry off treatment than blanket ddry off?
cost of treatment
| iatrogenic udder contamination due to the fact that treatment not designed for intramammary in small ruminants
95
How is mastitis contrnolled in small ruminants?
post milking teat disinfection
| milking order important
96
What kind of vaccines are out there for small animal mastitis?
autogenous
| no J-5 vaccine trials
97
What is important to remember for control of environmental mastitis?
suckling lame as fomite
