bovine mastitis and production of quality milk (Donovan) Flashcards
(51 cards)
1
Q
alveoli
A
- milk synthesis
- oxytocin responsive smooth muscle
2
Q
ducts and ductules
A
collection of milk
3
Q
gland (udder) cistern
A
storage of letdown milk
4
Q
teat cistern
A
storage of letdown milk just prior to removal (milking or suckling)
5
Q
teat canal
A
- first and most important line of defense against invasion by patogenic bacteria
- smooth muscle
- squamous epithelium and thick layer of keratin
- keratin: bacteriostatic properties
6
Q
mastitis (def)
A
- inflammation within the mammary gland
- complex disease
- many causes
- varying intensity
- variable duration
- variable residual effects
7
Q
inflammation characterized by
A
- heat
- pain
- redness
- swelling
- disturbed function
8
Q
clinical forms of mastitis
peracute
A
- most severe form
- CS progres over 4-12 hour period
- local signs severe plus systemic signs
- fever
- anorexia
- dehydration
- depression
- muscle tremors
- +/- diarrhea
- death
9
Q
Clinical Forms of mastitis
acute
A
- all five gross signs of inflammation
- mild depression and fever
10
Q
Clinical forms of mastitis
subacute
A
- cardinal signs of mastitis subdued
- no systemica signs
- most common clinical form
11
Q
Clinical forms of mastitis
Subclinical
A
- inflammation in absence of gross signs (only detected in milk)
- Leukocytes, fibrin clots, serum in milk
- most common form of mastitis
12
Q
Clinical form of mastitis
Chronic
A
- inflammation persists over weeks/months
or
- periodic flareups that produce acute or subacute clinical signs
13
Q
Primary udder pathogens
A
- staph aureus
- strep agalactiae
- mycoplasma sp
- strep dysgalactia
14
Q
Environmental pathogen (major)
A
- Strep uberis
- Strep dysgalactia
15
Q
Environmental pathogens (minor)
A
- staph coag neg
- Colforms
- A. pyogenes
16
Q
Streptococcus agalactiae
A
- non tissue invader
- pathogenesis
- irritant accumulates
- decreased milk production
- inc som cell count
- susceptible to penicillin and others
- can be eradicated
- rare on farms
17
Q
somatic cell counts
A
- leukocytes
- epithelia cellular debris in milk
18
Q
Control of strep ag in a herd
A
- post milking teat disinfection
- dry cow therapy
- ID infected cows and treat
19
Q
Dry cow therapy
A
- at the end of 300/330 days
- infuse antibiotics into mammary gland
- routine on all dairy farms
20
Q
Blitz treatment
A
- post-milking teat disinfection
- dry cow Ab therapy
- treatment of all strep ag positive 1/4s
21
Q
only bug controlled by TX
A
strep ag
22
Q
Staphylococcus aureus
A
- contagious mastitis
- mainly subclinical and chronic
- micro-abscessation within the gland
- peracute form less common
- this leads to gangrene of udder
- reservoirs
- milk
- teat skin
23
Q
staph aureus
pathogenesis
A
- penetrates into tissue
- produces deep-seated foci of inflammation
- produces toxins
- coagulase
- hemolysis: gangrenous mastitis
- penicillinase
- beta lactamase
24
Q
staph aureus shed in
A
relatively low numbers
25
staph aureus causes moderate
increase in somatic cell count
26
staph aureus controlled by
* teat dipping
* prevention
\*can't be controlled by treatment
27
Mycoplasma sp
* **contagious** mastitis organism
* of most concern is M. bovis
* also causes penumonia, otitis media/interna & arthritis in calves
* often subclinical
* mastitis can spread to all 4 quarters
* white coffe-ground appearance to milk
28
difficulty in treating/detecting mycoplasma sp
* non-responsive to AB
* periodic shedding possible
* specialized culture media required
29
strep uberis &
strep dysgalactia
* environomental
* non susceptible to eradication
* opportunistic
30
S. uberis
* acute and chronic mastitis
* indistinquishable from strep ag
31
S. dys
* infections after teat injury
* enhanced by presence of teat lesions
* viral
* mechanical
* chemical
* chapping
32
95% rule
* 95% of mastitis due to
* strep ag
* staph aureus
* strep uberis
* strep dysgalactia
* coliforms
33
Coliforms
* environmental, opportunistic organisms
* E. coli, Klebsiella, Serratia, Aeromonas
* cause peracute to acute mastitis
* can kill cows
* low numbers of bacteria shed in milk
34
Herds wtih low SCC may be at inc risk of
* acquiring coliform infections
* protective effect of elevated SCC
35
one of the first signs of peracute mastitis
watery milk
36
coliforms mastitis
* characteriazed by
* sudden sweeling of affected quater
* fever, muscle tremors, rumen statis, dehydration, +/- diarrhea
* udder secretion serous w/o leukocytes (pus) or fibrin, and later with both in milk
37
Coliform pathogenesis
* Endotoxins
38
Monitoring and assessment of herd mastitis
* # clinical cases
* Bulk tank milk eval
* California mastitis test
* Individual somatic cell count
39
Goal for mastitis
* \< 3% of milking population/month
* 0.75%/week
40
consideration when counting # clinical cases
* stage of lactation
* geographic location
* parity (1st lactation cows...?)
41
contagious mastitis bugs
| (purist perspective)
* staph aureaus
* strep ag
* mycoplasm
42
coliform contamination from
feces
| (look at bedding)
43
regulatory limit of somatic cell count
450,000 cells/mL
44
California Mastitis test
* indirect measure of somatic cells in milk
* good screening test for subclinical mastitis in a herd
* good at IDing cows with high SCC (\>1,000,000)
* Not good for differentiating between infected (\>200,000) and non-infected cows (\<200,000)
45
Mastitis Control Program
1. **proper milking management**
2. environmental control
3. **dry cow therapy**
4. milking machine maintenance
5. **treatment protocols**
6. vaccination
46
Pre-milking management
* quietly bring cows into milking parlor to be milked
* avoid excitement
* thoroughly clean and dry udder and teats
* dry is preferable to clean
* dip (contact time)
* iodine (30 seconds)
* chlorine (5-10 seconds)
* strip (look for mastitis)
47
milking management
* avoid liner slips
* vacuum leak
* contributes to severe coliform mastitis
48
Post-milking management
* make sure cow is milked out
* dip all 4 teats
* send cow on her way to a feedbunk full of fresh feed and water
* keep them standing!
49
Environmental control
* bed freestalls at least once daily
* control heat stress
* dry cow therapy
* infuse AB into mammary gland
50
vaccinations against mastitis
* E. Coli
* core vaccine, only one that works
* Staph aureus
* Mycoplasma bovis
51
Summary
* Milk clean, dry teats
* post-milk disinfection
* dry, clean housing
