Control of mastitis Flashcards
CONTAGIOUS mastitis - where does organism tend to live? How does it cause infection? When?
Organisms prefer to live in the udder and teat skin
Often cause subclinical infection
Mostly spread from cow to cow at milking
Examples of contagious mastitis pathogens 4
S.agalactiae
S.dysgalactiae
S.aureus
(S.uberis - but originally an environmental organism)
Be aware there are others!
Minor pathogens include:
Corynebacterium bovis
Coagulase-negative Staphylococci (CNS)
Unlikely to be pathogenic. May have protective function.
ENVIRONMENTAL mastitis - where does organism tend to live? How does it cause infection? When?
Live in the environment
Sporadically gain entry to the udder
Tend to either be rapidly eliminated or cause very serious mastitis
But if quarter is infected during dry period can persist and cause problems in early lactation
From dirty environment but can gain entry at milking tie.
Other important factors:
-housing design and management
-cubicle design
- yard management
- scraping of dung
- dry cow housing
Which environmental organisms are most responsible for environmental mastitis cases? 7
Coliforms and E.coli
Also S. uberis and Klebsiella
Rarely but possibly Bacillus cereus, fungi and yeasts
Which cells make up a SCC? 2 When are these high? 2
inflammatory (increase with bacterial infection) and epithelial (these increase towards the end of lactation and are high immediately after calving)
What is the SCC for a.) clinical mastitis b.) subclinical mastitis?
a. ) millions of cells/ml
b. ) >200,000 cells/ml
Outline the features of subclinical mastitis
tends to go undetected and survive in quarters for long periods, causes prolonged mildly elevated SCC of quarter >200,000, tends to spread at milking time, can get many quarters in the herd infected each with a high cell count, tends to be contagious organisms, a high number of subclinical infections will cause elevated bulk tank SCC, so bulk tank SCC is an approximate indication of the proportion of quarters that are infected, indicator of the PREVALENCE of mastitis
Define BMSCC
Bulk milk somatic cell count
What are the important values of the BMSCC (4)?
Target = 200,000/ml
Milk cannot go for human consumption by EU law if > 400,000/ml
What are the important features when trying to control CONTAGIOUS mastitis?
Control spread at milking time
Eliminate reservoirs of infection (dry cow therapy, culling and identify infected cows (subclinical) using individual cell counts)
DO THIS WITH THE 5 POINT PLAN
What is the 5 point plan?
For the control of contagious mastitis:
- ) Prompt detection and treatment of clinical cases
- ) Post-milking teat dip (PMTD)
- ) Dry cow therapy
- ) Cull persistent offenders
- ) Regular servicing and maintenance of milking machine
How should cases be promptly detected?
Detect in parlour, do fore milking (make 4-5 strips to make a visual assessment of the milk; also aids milk let down and flushes out the milk most laden with bacteria), Consider milk over floor (Strip Cup) and splash back
Important parlour hygiene tips - 4
Use individual paper towels - one per cow
Never use udder cloths
Wear gloves
Can use pre-milking teat dips to further improve hygiene.
What is PMTD? Why do this?
Post-milking teat dipping
WHY = teat orifice remains open for 30-40 minutes after milking, keep cows standing after milking to allow sphincters to close before they lay down as bacteria can be transferred onto teat skin during milking and bateria multiply and invade milk canal
What to use to PMTD?
Disinfectant which coats teat skin and kills bacteria. Also can aid in maintaining teat skin in good condition. EXAMPLES: IODOPHORES CHLORINE BASED CHLORHEXIDINE QUATERNARY AMMONIUM COMPOUNDS Several other agents too
