Causative agents
1. Contagious pathogens
Staphylococcus aureus
Streptococcus agalactiae
Corynebacterium bovis
2. Environmental pathogens
Streptococci other than Str.agalactiae
Coliforms
Coagulase negative staphylococci (CNS)
- Arcanobacterium pyogenes, Yeast-like fungi,
Pseudomonas aeruginosa occasionally found
particularly in clinical cases
Differential diagnosis
Nonspecific (aseptic) mastitis
(No microorganisms isolated from milk samples)
1. History taking
- high SCC herds
- milking procedure and milk hygiene
- milking system
- herd management
2. Clinical examination
Clinical mastitis
- the infected quarter swollen, painful to touch
- the milk visibly altered by the presence of clots,
flakes or discolored serum and sometimes blood
Subclinical mastitis
- apparently normal udder and milk
- However, microorganisms and WBC (somatic
cells) found in elevated numbers in milk
3. Bacterial isolation
Sampling
- Before sampling, teats swabbed with 70% Alcohol
- Quarter milk samples separately collected
- Milk samples immediately chilled .
- Each quarter milk sample identified as A,B,C and D
Culture on 5% Sheep Blood agar plates
- One plate for one cow by quadrantizing the plates
- 10 µl of each quarter sample is streaked
|
- Incubated aerobically at 37°C
- Plates examined after 18 hours and reincubated
for 18-24 hours
4. California Mastitis Test (CMT)
- Estimation of somatic-cell counts (SCC) in milk
Table : CMT reaction and SCC
| Reaction |
|
Gelling |
Somatic cell count |
| Neg |
: |
None |
<100,000 |
| Trace |
: |
Slight |
>300,000 |
| +1 |
: |
Slight-moderate |
>900,000 |
| +2 |
: |
Moderate |
>2,700,000 |
| +3 |
: |
Heavy |
>8,100,000 |
The results not necessarily correlating with bacterial examination
Control
1. Contagious mastitis pathogens
(Spread from cow to cow during milking. Disease
prevalence correlates with aging and lactation
period)
Spread control:
- separate infected cows
- milk uninfected cows first
- use effective sanitizer in wash water
- wash and dry teats with clean towels
- dip teat immediately after milking
Reservoir control:
- Str. agalactiae
- primary pathogen in udder
-can be eliminated from herd
- very susceptible to penicillin
- Sta. aureus
- adhere firmly to epithelial cells
- may develop resistance to antibiotics
2. Environmental mastitis pathogens
(Infection spreads anytime. Irresponsible to age.
Predominantly around calving)
Spread control:
- Clean and dry teats
Reservoir control
- Clean, dry, hazard-free environment
|
