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Mastitis, target for mastitis: 30 clinical cases/100 cows/year - Coggle…
Mastitis
pathogenesis
bacterial
staphylococcus aureus
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haemolytic, catalase positive and coagulase positive and produces several toxins including haemolysins and leucocidin (kills leucocytes).
It can persist in neutrophil lysosomal vacuoles and chronic infections often lead to the formation of scar tissue. Somatic cell counts may be raised or fluctuating and excretion of the organism from chronic cases may be intermittent
some strains produce β lactamase which confers resistance to β lactam antibiotics (penicillins and
cephalosporins).
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poor cure rates often lead to chronic infections (can persist in neutrophil lysosomal vacuoles, also scar tissue
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coliforms
Other environmental coliforms implicated in mastitis include Enterobacter, Citrobacter, Klebsiella, Serratia, Proteus, Pseudomonas, Hafnia and others.
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Pseudomonas aeruginosa is sometimes found in association with contaminated water sources, especially warm water header tanks, bore holes. Signs vary from chronic recurrent cases to acute gangrenous mastitis.
streptococcus uberis
Opsonisation and phagocytosis is poor, such that on occasion the organism can survive intracellularly, making antibiotic treatment important to achieve good cure rates. Certain strains appear to be more adapted to the udder, can set up chronic infections and spread from cow to cow i.e. behave as contagious pathogens. It has recently become possible to differentiate the contagious from the environmental strains through MALDI-TOF profiling.
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streptococcus agalactiae
gram positive, beta haemolytic coccus is highly contagious
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mycoplasma bovis
This very small, slow-growing bacteria lacks a cell wall and requires special selective culture (taking up to 14 days) or else PCR to diagnose.
The mastitis is usually unresponsive to antibiotic therapy, sometimes spreading to all 4 quarters and leading to agalactia even though the cow may not be systemically ill.
Although self-cure can occur, culling is often the best option due to the possibility of chronic infection and the risk of passing it on to other cows. Infections can be blood-borne, leading to polyarthritis and/or pneumonia. In addition, calves drinking infected milk can develop pneumonia, otitis media or arthritis although they may also become infected through respiratory spread. Interestingly, many herds with M bovis pneumonia in the calves never see it as a cause of clinical mastitis in the milking herd
E.coli
endotoxins (lipopolysaccharide from bacterial cell wall) are responsible for the toxic effects, but poor adhesion to the endothelium makes chronic infections unlikely
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infections usually through teat canal, but also through trauma or wounds
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PROTOTHECA
This is an algae which is widespread on farm, although unusual as a cause of mastitis. It is found in contaminated water and decaying plant matter/manure.
The mastitis may result in a swollen quarter with clots in milk but the cow not usually sick. It may be unresponsive to treatment
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summer mastitis
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hot, hard, swollen quarter with tense and enlarged teat
purulent foul smelling secretion, severe cases may burst and discharge
mild cases may calves in with blind quarter, fibrous core in teat
organisms sensitive to penicillin, but response to tx poor
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5 point mastitis plan
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post milking teat dip
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iodophores, chlorine based, chlorhexidine, quaternary ammonium compounds
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clinical mastitis
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peracute
rapid onset of severe inflammation, pain and systemic symptoms --> severely ill cows within a short period of time (6-12h post infection)
change of quarter and milk character (clots/flakes), pyrexia
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chronic
long term recurring persistent cases of mastitis with few symptoms between repeated occasional flare ups over a period of several months
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subclinical mastitis
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detection
testing milk for somatic cell counts (SCCs) (predominantly leukocytes) using california mastitis/milk test or automated methods
inflammatory changes and decreased milk quality may start with SCCs as low as 100,000 cells/ml
An SCC of over 200,000 cells/mL in a cow indicates a high likelihood of infection
the higher the SCC in a herd bulk tank, the higher the prevalence of infection in a herd
herd SCCs <200,000 cells/mL are desirable, lower counts can be attained
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mastitis patterns
contagious
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strep agalactiae, strep dysgalactiae, staph aureus, strep uberis
environmental
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E.coli, strep uterus, klebsiella, coliforms, bacillus cereus, fungi, yeasts
control
environmental mastitis
cubicles 2.3m long, 1.2m wide, barrier 1.7m from back on floor
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inflammation of the mammary gland with the possible pathological cardinal symptoms of redness, heat, hardening and pain
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