Mastitis Flashcards
What are the two presentations of mastitis?
ClinicalSubclinical
What is the difference between clinical and subclinical?
Clinical we can observeSubclinical only have a high cell count
What is subclinical mastitis not associated with?
Pain
What are the two different times mastitis are seen?
Dry periodLactation infection
What is the most common type of mastitis within dry period? Lactation?
Dry period - environmentalLactation - contagious and environmental
What is Orbeseal?
A plug stuck in the end of the teat preventing infection within the dry period - physical barrier
What is the difference between contagious and environmental mastitis?
Contagious occurs within the milking parlourEnvironmental occurs outside the parlour
What type of mastitis does E. coli mainly cause?
Environmental
What type of mastitis does Stapholococcus usually cause?
Contagious
What do the contagious typically look like compared to one another?
Genetically uniform
How do the environmentally causing mastitis bacteria appear?
Genetically different
What are the risk factors with mastitis?
HostEnvironmentAgent
What is the average incidence of mastitis per year?
35 per 100 cows per year
Which region of England has slightly higher cases of mastitis every year?
South-East England
What causes mastitis?
Multiple factors - not one single thing
What occurs with a lower bulk tank somatic cell count?
More severe cases of mastitis but less of them
What type of mastitis occurs with a high bulk tank somatic cell count?
Subclinical contagious mastitis
What does mastitis impact upon in the dairy?
Quanitity of milk lost (actual and potential)Quality of milk lost (residues and penalties for high SCC)
Why does a high SCC cause penalties to the farmer?
Enzymes in the milk reducing cell count as well as making it more difficult to use in cheese
When does clinical mastitis occur?
Exposure to pathogen and then enters teat and into mammary gland
What do you see in clinical mastitis?
Always changes in milk - composition/quality/dotsSometimes other signs
Describe grade 1 clinical mastitis
Milk change onlyDecreased milk yield
What does a microfilter do in the dairy?
Takes out milk spots allowing clinical mastitis to be detected
Why is pre-stripping the teat always important in the parlour?
Main way for checking clinical mastitis
Describe acute grade 2 clinical mastitis
AcuteMilk changesUdder changesMilk yield decreased
Describe chronic grade 2 clinical mastitis
Same as acute but persists
Describe grade 3 clinical mastitis
Same as grade 2 but with systemic sick cow
What are some of the main bacterial causes of clinical mastitis?
Strep. agalactiaeStrep. dysgalactieaStrep. uberisStaph. aureusE. coliOther agents
Describe sub-clinical mastitis
Elevation of somatic cell countPositive Californian Milk testReduced milk yield
What can be used instead of an official Californian Milk Test agent?
Fairy liquid - essentially detergent that breaks down membranes
What are we looking for in a Californian Milk Test?
Any change in composition of the milk - becomes more “gloopy”
What are the main bacterial causes of subclinical mastitis?
Staph. aureusStrep. uberisStrep. agalactiaeCorynebacterium bovis
What do we need to know from history with mastitis cases?
DurationDevelopmentStage of lactation and gestationAgeTreatment and its responsePrevious episodesSCC data
Describe the clinical exam for mastitis cases?
Systematic clinical examUdder exam - inspection, palpation, lymph nodesMilk examMilk sample (CMT)
What are the three choices of antibiotics for mastitis treatment?
SystemicIntramammary during lactactionIntramammary in a dry cow
Why should we check the intrammamary antibiotics before application?
Lactation ones in dry cows won’t protect long enoughDry ones in lactating cows will cause major financial problems
What other treatments can be used for mastitis?
Oxytocin - allows release of milkNSAIDs - reduces painCorticosteroids - toxic mastitis or new pathogen with inflammationFluid therapy - toxic mastitisCalcium - supportDextrose - support
What can’t you tell upon the presentation of mastitis?
Pathogen causing the disease
What does the choice of antibiotic depend upon in mastitis cases?
SensitivityPharmacokineticsAvailabilityCostsHerd historyWithdrawal time
What three cows do we sample when culturing for mastitis?
Recurrent casesPersisitent infectionRise in SCC
What are the three samples we can take for milk?
Bulk tankPooled one cow sampleIndividual quarter sample
Describe sampling an individual quarter
Cleanse udderSwab teat end until swab is clean2 pre-strips2ml in sterile containerLabel with name, number and quarter
Where do the organisms causing contagious mastitis live?
Prefer to live in the udder and teat skin
What type of infection do contagious mastitis organisms cause?
Subclinical
When is contagious mastitis spread?
Cow to cow at milking - human spread
Where does Strep. agalactiae live?
Exclusively within the udder - largely eliminated
Where does Strep. dysgalactiae live?
Tonsils, udder, teat, teat lesions
What is Staph. aureusresistant to?
Most antibiotics as persist and culling usually only option
Where is Strep. uberisusually picked up from?
Damp straw
What is unique about Strep. uberisamong mastitis causing pathogens?
Picked up environmentally but spread contagiously
What are two other minor pathogens that can cause contagious mastitis?
Corynebacterium bovisCoagulase negative staphylococci (CNS)
Where do environmental pathogens of mastitis live?
Environment sporadically gaining entry to udder
What do environmental pathogens of mastitis cause?
Nothing as rapidly eliminated or serious mastitis
What is the dry period of a cow?
Generally up to 60 days
When do environmental pathogens causing mastitis enter the teat?
Milking time
What is important in preventing environmental mastitis?
Housing design and managementCubicle design, yard management and scrapingDry cow housing also important
What are the main organisms that cause environmental mastitis?
E. coliStrep. uberisKlebsiella - wood shavingsColiformsBacillus cereusFungiYeasts
What are somatic cell counts not?
Bacteria - normal cells in milk (inflammatory, epithelial etc.)
When do epithelial cells increase?
Towards the end of lactation and are high immediately after calving
What is the normal lactation time in cows?
305 days
Why do somatic cell counts increase with infection?
Inflammatory cells increase
What shouldn’t SCC increase above?
200,000 cells per ml
How can elevated bulk tank SCC increase?
Usually high subclinical infection numbers
What is the bulk tank SCC an indicator of?
Mastitis prevalence
What is usually imposed on a farm with a SCC above 200,000 cells/ml?
Financial penalty
What is the main way to control contagious mastitis?
Eliminate reservoirs of infection
What should be used in dry cows to help prevent mastitis infection?
Dry cow therapy - don’t dry cow up but prevent subclinical infections and clearing persistent infections up
Describe the 5 points of the 5 point plan
1 - prompt detection and treatment of clinical cases2 - post milking teat dip3 - dry cow therapy4 - cull persistent offenders5 - regular servicing and maintenance of milking machine
Why is hygiene important in control of mastitis?
Prevents spread of mastitis from cow to cow in parlour
What should never be used in the milking parlour?
Udder cloths
What is the first thing that should be done after milking?
Keep them standing for 30-40 minutes after milking - teat orifice remains open
What are the two most common types of pre-milking teat dip?
IodophoresChlorine based
What do long acting antibiotics aim to do in dry cow therapy?
Remove existing sub clinical infections during dry periodPrevent further infections getting established in udder
What does teat sealant do?
Inert substance which is infused and blocks it preventing bacteria entering during dry period
Why is it important to record and mark dry cows?
Prevent cow getting milked by accident
What is a definition of a persistent mastitis offender?
3 cases or more during one lactationPersisitently high individual SCC which doesn’t respond to treatment
What are the three actions with problem cows?
Put in problem herd - milk at end of milking so as not to spreadTreatment at dry offCull
What is a “new” cow with high SCC value on the herd companion website?
The first time a high SCC has been recorded but not the first milk recording in this lactation
What is a “first” cow on the herd companion website?
Cow with both a high SCC and the first recording this lactation
What is a “repeat” cow on the herd companion website?
Cow that had a low SCC in the previous month but this is at least the second time the cow has had a high SCC
What is a “chronic” cow on the herd companion website?
A cow with a high SCC at this recording and the previous milk recording and possibly others
What is a “low to low” dry period cow?
Cow had low SCC when dried off and was still low when the cow was calved - ideal
What is a “low to high” dry period cow?
The cow had a low SCC at dry off but was high when calvingCow has become infected during the dry period - disaster
What needs to be looked at if there is a high proportion of “low to high” dry period cows?
Dry cow housing and management
What is a “high to low” dry period cow?
Cow was infected at dry off (high SCC) but by calving the infection had cleared (low SCC) - excellent
What is a “high to high” dry period cow?
Cow was infected at dry off and despite any treatment they were still infected at calving
Why can liners cause mastitis?
Get transferred from cow to cow - get cracked and can let pathogens into the liner and transmit disease
How many milkings do milk machine liners last?
Rubber - 2500Silicone - 10000
What is the equation for calculating the liner life?
(2500number of milking units)/(number of cows2)
What is the vacuum reserve?
How much extra vacuum there is in the vacuum pump
Why do we need a vacuum reserve?
To prevent reflux of milk back into the teat
How do we test that a constant vacuum is being applied?
Open 1 in 5 unitsIf vacuum drops by 2kPa it is insufficient
How quickly should the vacuum recover in the milking machine?
Less than three seconds
What is liner slip?
Air leks into the top of liner making a distinctive sound and causes reflux of milk back into teat and causes mastitis
What are the two main ways of controlling environmental mastitis?
Control environmentParlour factors - teat preparation, clean and dry at milk
How often should indoor cow housing be fully cleaned out?
Every 3 weeks
Describe a good cubicle for a standard dairy cow
2.3m long1.2m wideBarrier 1.7m from back on floor
What does a Bactoscan estimate and what is it not?
Estimates number of bacteria in milkNot actualnumber of bacteria
What are the 4 stages to herd health planning?
Where are we now?InvestigateImplement changesHave things improved?
What is the target for clinical mastitis cases on a farm?
30 cases per 100 cows per year
What must be kept to allow good herd health planning?
Accurate records
What are the two ways we can set a target for mastitis?
SCC in bulk milkClinical cases of mastitis
What does the bulk milk SCC indicate?
Prevelance of mastitis - subclinical
What does bulk milk SCC not usually include?
Clinical cases of mastitis as farmer tends to throw it away
What do we need to decide when investigating mastitis?
Contagious or environmental
Why is looking at the number of antibiotics intra-mammary treatments sold a good investigation of mastitis?
Number sold tells us how effective antibiotic treatment isToo high then treatment may not be effective or not recording effectivelyToo low then either over recording or not administering or using homeopathic treatment
Why should we look at problem cows?
Could be a reservoir of mastitis infection
What are the three options for problem cows?
CullIsolate into problem groupTreat
What shouldn’t we put problem cows with?
Calving herd
What should we do with a problem group of cows?
Milk the group last and house separately
Why should we stay a long time when observing milking routines?
To ensure that herdsman wasn’t just “putting on a show”
Why should we talk to herdsmen about milking routines?
Generally know what’s going on and can give you an insight into what could be the cause of the problem
What are ten things to check for when observing the milking parlour?
HygienePre dipStrip and wipe teatTeats clean and dryPaper towels/clothsStimulationLiner slipsOvermilkingPost dippingRelaxed cows
What is a very rare cause of stress in cows within the milking parlour i.e. why wouldn’t they want to go in?
Stray voltage - milking machine gives them an electric shock
What should we observe when checking the environment cows are housed in?
Look at cowsCow cleanliness scoreCubiclesComfort
What is the cow comfort index?
Proportion of cows which are standing one hour before milking - target is less than 15%
What is the requirement for the Bactoscan?
< 50,000/mlShould target to get <20,000/ml
What are the 4 sources of bacteria in the milk?
Mastitis cowContamination from faeces - dirty teat, wet teat, poor milking technique etc.Milking machine dirty - not washed properly causing bacteria growthFailure of refrigeration in bulk tank - 4 degrees C
When are samples taken?
At random by lorry driver at least once a week
What are tested in the samples taken?
Bulk SCCBactoscanFatProteinUreaAntibioticsWater
Why is urea results provided in a milk sample?
So farmer can manage herd - doesn’t get paid on itPurely a courtesy
What are the two ways water can get into milk?
Farmer runs a hose into the milk to bulk volume upTank hasn’t drained properly after washing out
What are the two tests that can be used to investigate mastitis?
California milk testSterile tube sample - culture
What is a main area we should investigate the udder on with mastitis?
Teat end
What are some of the key things we should do when investigating mastitis?
Spend time on farmLookListenTalk to farmer and staffAll about husbandry and peopleKeep going back
Where do most clinical cases of mastitis occur?
Lactating gland
Which bacteria causes disease in the dry cow and immature glands?
Trueperella pyogenes
What is the most common route of entry into the mammary gland?
Via the teat canal - galactogenic route of entry
What are the three routes of entry of microorganisms into the mammary gland?
GalactogenicHaematogenousPercutaneous
What are the three methods the teat canal has to resist infection?
Smooth muscle sphincterKeratin from epitheliumFurstenberg’s Rosette
How does Furstenberg’s Rosette help the teat resist infection?
Prevent physical entry into canalFatty acids and cationic proteins act as antibacterialsSubepithelial plasma cells produce immunoglobulin
What physical factors of the udder help resist infection?
Sphincter and keratin of teatFlushing action of milk
What are the soluble factors that help resist mastitis infection?
LactoferrinLysozomesComplementsCytokines
What are the cellular factors that help resist mastitis infection?
NeutrophilsMacrophages laterNatural Killer Cells
Which parts of the adaptive immunity help resist mastitis infection?
LymphocytesImmunoglobulins - mainly IgG
What are the three presentations of mastitis pathologically?
PeracuteAcuteSubclinical chronic
When do peracute mastitis generally occur?
Mostly occur around parturition and death within hours
What is the gross appearance of peracute mastitis?
Swollen painful quarterRapid progression to moist gangreneDark blue to black in colourBlistering and oozing serumBecomes cold to the touchVariable number of dark haemorrhagic lobules on cut surfaceVentral abdominal oedemaMay be comatose
How does acute mastitis appear microscopically?
Extensive interstitial oedema with neutrophilic infiltrationVacuolation and desquamation of acinar and ductal epithelium
How does acute mastitis progress to chronic mastitis?
Fibrosis obliterates aciniDucts obstructed by polyps - milk can’t be brought downRetention cysts anterior to blocked ductsAlso abcess formation depending on pathogen
What happens following chronic mastitis?
Involution - temporary loss of secretory tissueFibrosis - permanent loss of secretory tissue
Why should we consider just culling cows infected with Staph. aureus?
Really difficult to treat and cure due to botryomycosisArea of fibrous tissue surrounding bacteria making it very difficult for antimicrobials to penetrateCan flare up and shed causing infection of other cows so best option is to cull
What can occur with subclinical mastitis with further flare ups?
Can lead to fibrosis of ducts leading to drop in milk yield
What is the gross appearance of chronic subclinical mastitis?
Gland is hard and atrophic
What is the microscopic appearance of chronic subclinical mastitis?
Similar to chronic clinical mastitisPermanent loss of secretory tissue due to progressive destruction
What is the main cause of clinical mastitis?
Streptococcus uberis
What accounts for more than half the cases of clinical mastitis?
E. coliStrep. uberis
What are the four main causes of subclinical mastitis?
Coagulase negative staphylococciS. uberisS. aureusCoreynebacteriumOther
What are the 10 main organisms that cause lactating mastitis?
S. aureusE. coliS. uberisS. agalactiaeS. dysgalactiaeM. bovisC. bovisPseudomonas aeruginosaKlebsiella penumoniaeYeasts
Where does S. aureuslive?
Skin and mucous membrane of animals and humans
How does S. aureus enter the mammary gland?
Teat canal
What range of disease can S. aureuscause?
Subclinical through to severely gangrenous
What are 70% of S. aureus strains?
Beta-lactamase positive - resisitant to antibiotics
How does S. aureusavoid immune response?
Walls itself off using fibrous tissue preventing phagocytosisAlso hides inside epithelial cells
How can S. aureuscause further inflammation without invasion?
Hypersensitivity - immune response if previously exposed to pathogen
Is there a vaccine for S. aureus?
No
What are the seven pathogenicity factors with S. aureus?
Alpha toxin - necrotizing toxinBeta toxin - sphingomyelinaseTSST-1 - superantigenPolysaccharide capsuleProtein AEnzymesFibronectin-binding protein - allows adherence
What are the four pathogenicity factors of S. agalactiae?
Streptolysin SSTST-1 - superantigenEnzymesPolysaccharide capsule
What is the natural habitat of S. agalactiae?
Teat canal of the udder
Why is S. agalactiae no longer a real problem?
Only really lived in udder and infected animals have been culled out
What are the three pathogenicity factors with S. dysgalactiae?
STST-1 - superantigenEnzymesPolysaccharide capsule
What is the natural habitat of S. dysgalactiae?
Outside the udder teat and not host adapted
What does S. dysgalactiae require to cause infection?
Trauma or wound
What type of mastitis does S. dysgalactiae more oftenly cause and why?
Acute mastitis as not host adaptive
What is the natural habitat for S. uberis?
Environment (faeces) requiring wound or trauma to invade tissue
What type of mastitis does E. colicause?
Acute mild mastitis
What are the pathogenicity factors of E. colithat help make it antimicrobial resistant?
Alpha-haemolysinCNF-1EndotoxinIron acquisitionK-typesPili - allow attachment
Is there a vaccine for E. coli?
Yes - killed E. colistrain
Where does M. bovisgenerally live?
Genital and respiratory tract
What occurs with M. bovis?
Reaches udder by haematogenous spread causing a dramatic drop in milk yield
What are the primary agents involved in dry cow mastitis?
Trueperella pyogenesS. dysgalactiaePeptostreptococcus indolicus- anaerobe
Where do many lactating mastitis infections begin?
During the dry period
What are the main causes of mastitis in ewes?
Mannheimia haemolyticaS. aureusE. coliStreptococciMycoplasma agalactiae
