Mastitis continued Flashcards
Streptococcus Agalactiae:
type of pathogen
Blood agar
A contagious mastitis pathogen
Gram positive cocci
non haemolytic
Forms very small pin prick colonies on blood agar
What type of mastitis does streptococcus agalactiae form?
mastitis graded at 1 and 2
Usuallt sub clinical = high Scc
Not associated with persistent infection
How does streptococcus agalactiae appear in the herd and how controlled?
- Failure of parlour hygeine OR introduced by bought in animal
- Control = good hygiene
Reduce existing infection - treat cases, cull chronic, dry cow therapy and prevent spread within herd:
Milking parlour
Wear Gloves
No common udder cloths/ wipes
Early detection and treatment
Post milking teat disinfection
Milking order
Maintain milking machine correctly (liners and vacuum)
What drug used to treat streptococcus agalactiae
Responds well to antibiotics (penicillin)
Streptococcus dysgalactiae
about
What shoudl you immediately think?
Gram positive coccus
Small pin point colonies on Edwards Medium Partial Haemolysis Green Zone
Alpha haemolysis
Udder adn teats are being damaged in some way to cause this
Streptococcus dysgalactiae source of infection
Udder, teat skin particularly when skin damaged, tonsils and so cows and heifers licking each others teats important
Streptococcus dysgalactiae What sort of infection does it cause?
Can cause persistent infections
If Streptococcus dysgalactiae is causing problems in herd what should you do?
particularly check teat condition as proliferates when damaged and look for milking machine pulsator or vacuum problems, check use of emollients in teat dips
Responds well to antibiotics (penicillin)
What is mycoplasma?
genus of bacteria that lack a cell wall around their cell membranes.[1] This characteristic makes them naturally resistant to antibiotics that target cell wall synthesis (like the beta-lactam antibiotics = penicillin).
Mycoplasmas are totally dependent on the animals they infect to provide the nutrients they require
Spread by aerosol
Types of mycoplasma we see in dairy?
M. bovis and M. californicum
What does mycoplasma bovis also cause, other than mastitis
infertility, metritis, otitis media in calves = head tilt, arthritis, keratoconjunctivitis, pneumonia in calves and adults. AGGRESSIVE mastitis where no cure
Interestingly, Often produce marked milk drop and swollen quarter although the cow is not systemically ill
Where do cows mainly catch M bovis from?
Highly contagious in parlour , aerosol spread and haematogenous (originated and carried in blood)
What pathogenesis to the udder do mycoplasma species cause and why?
Lipoprotein on outer surface stimulates host immunity alveolar epithelium degenerates massive leucocyte outpouring abscesses, alveolar hypertrophy, fibroplasias around ducts PUS
destroyed quarter
Can you ever be sure mycoplasma isn’t the cause of disease
No as can be sub clinical = reduced tield, high SCC, could alwasy be mycoplasmas
Can be shed for moths and even life!
Is mycoplasam easy to culture? and treat?
Difficult to culture; special medium; special request
In vitro sensitivity to several antibiotics , but success very poor = cull
Can we feed mastitis milk to calves?
Do not feed milk to calves as could cause disease in calves e.gg mycoplasma causes pneumonia/otitis
Control of mycoplasma
affected cows often culled
milking order (affected cows milked last)
Disinfect cluster thoroughly etc. to stop spread;
hygeine like spoken about before
What is Coagulase NEgative Staphylococci?
a minor pathogen that is only a problem in those herds that have good control of other pathogens.
Heifers are infected before claving. Causes mild disease including high SCC.
Spontaneous cure common
Treat with antibiotics; usually respond well to penicillin
Often regarded as the cause IF no other pathogens found
Repeat sampling or pure culture or number cases in herd may confirm importance
E coli
What type of pathogen?
Source?
What does it form on blood agar?
an environmental pathogen
source: bovine faeces however some evidence there may be udder adapted strains
Blood agar forms creamy white colonies
Haemolytic and non haemolytic
Gram negative rods
When is E Coli picked up?
When is it mostly commonly apparent disease?
and picked up any time in calving cycle- whole yr
Often picked up during dry period and induced when she goes from dry cow into environment where calves (peri-periparturient 3 weeks before and after))= most commonly where we see it as a systemic problem
Manifests as high SCC and clinical disease
What is a risk factor to ecoli?
Housed = risk factor
Build up of infection over housing period
wet, dirty, poorly ventilated conditions particularly bedding, cubicles, straw yards and calving boxes ,wet muddy fields
E coli pathogenesis
Contamination of teat end is followed by invasion of teat canal
Proliferates rapidly producing LPS endotoxin damages vascular and secretory tissue
Clinical outcome of the infection will depend on the quantity and speed of neutrophil influx:
Inadequate or too slow cow will develop endotoxaemia often fatal
not really a grumbling thing but acute bang
Clinical signs of E coli mastitis
All grades of clinical disease.
Grade 1
clots in milk (self cure)
Grade 2A
clots in milk, hard hot painful quarter
Grade 3 - COMMON
Very sick cow, endotoxaemic shock (usually post calving peri-parturient immunosuppression) udder variable can be cold or hot, hard or soft,
Milk varies from clots to blood
Important differential for downer cow post calving
Not commonly associated with subclinical mastitis and raised cell counts
< 15% become chronically infected
How to control E coli mastitis infections
in parlour
Pre-milking teat preparation - Remove the muck! pre dip
Loafing times after milking are contentious - half an hr after milking for teat to close but if main issue lameness then want to lie does asap
Appropriate dry cow therapy - sealent at start of dry cow period to stop infection getting in during dry period
Vaccine - Startvac- not eliminate disease, just reduce severity of clincial
