Mastitis in Cattle Flashcards
What are the 2 possible sources of pathogens causing mastitis?
- environmental
- contagious
What are common environmental pathogens causing mastitis?
- Gram-positive pathogens
- Environmental Streptococci, commonly Streptococcus uberis, Enterococcus spp.,
- Others such as Bacillus spp.
- Gram-negative pathogens
- Coliforms (E. coli, Klebsiella spp., Serratia spp. and many others)
- Non-coliform bacteria such as Pseudomonas spp.
What are common contagious pathogens causing mastitis?
- Gram-positive pathogens
- Staphylococcus aureus,
- Streptococcus agalactiae,
- Streptococcus dysgalactiae
- Mycoplasma spp.
What treatment is often used to treat mastitis in high cell count herds?
- Typically, bulk milk SCC>200 cells/ml
- More than 20% of cows with SCC>200 cells/ml
- Consider narrow spectrum intramammary
- Category D, good activity v Gram-positive
- Benzylpenicillin, (e.g., “Ubropen”)
- On label up to 5 days treatment
What treatment is often used to treat mastitis in low cell count herds?
- Typically, bulk milk SCC<200 cells/ml
- Less than 20% of cows with SCC<200 cells/ml
- Consider broad spectrum intramammary
- Category C, good activity v G+ and G- (penicillin and an immunoglycoside)
- Cefalexin & kanamycin, (e.g., “Ubrolexin”)
- Potentiated amoxicillin, (e.g. “Synulox”)
- Cephapirin, (e.g., “Mastiplan”)
How can we measure infection status after we treat clinical mastitis events and monitor “cure rates”?
using white blood cell counts in milk (“somatic cell count” or SCC)
How do you manage high cell count cows in lactation?
- Treatment of subclinical infections during lactation is generally associated with a poor chance of cure…and is poor antibiotic stewardship
- Most high cell count infections will cure during the dry period with antibiotic dry cow therapy
- “Chronic” infections (cows with multiple SCC>200), in older cows less likely to cure and may be suitable for culling
How do you manage high cell count cows at drying off?
- Antibiotic dry cow therapy products
- Published evidence that the chance of cure is increased if we combine antibiotic dry cow antibiotic with a non-antibiotic internal “teat sealant” when drying-off cows with SCC>200,000 cells/ml
Why use internal teat sealant at drying off?
- Was designed for use in uninfected cows
- No inherent antimicrobial activity
- Infused into the teat cistern
- Original UK work showed dramatic reduction in risk of new infection during the dry period using internal teat sealants
What is the selective dry cow therapy concept?
- uninfected cow with low cell count in last 3 milk recordings or no clinical mastitis in last 3 months will only have teat sealant at drying off
- infected cow with high cell count or clinical mastitis event in last 3 months will have intramammary antibiotic and teat sealant at drying off
What is the dry cow summer mastitis complex?
- Complex environmental pathogen aetiology
- Arcanobacterium (Trueperella) pyogenes
- Peptococcus indolicus
- Streptococcus dysgalactiae
- Disease of dry cows and heifers
- Transmission by sheep head fly (Hydrotea irritans) often implicated …
- Hot, hard, swollen, painful quarter
- Characteristic foul smell
- Dry cow often lame – noticed first?
- Can lead to abortion (pyrexia)
- Prognosis poor, quarter often lost
How can you manage the dry cow summer mastitis complex?
- Intra-mammary antibiotics useless
- Injectable broad spectrum (e.g. amoxicillin)
- Strip out affected quarter - may need to drain quarter by vertical incision into teat (below)
- Very likely to lose the affected quarter
- Prevention by reducing risk most important
- Fly avoidance (specific pastures, woods, streams)
- Fly control (spray, pour-ons etc.)
- Teat Sealants (Internal and External)
- Stockholm Tar, micropore tape etc applied to teats
How can you prevent spread of environmental mastitis in lactating cows?
- Clean bedding applied to any lying areas at least daily
- Scraping any faeces off the backs of the cubicles twice daily
- Access to outside (feed) areas?
- Scraping collecting yards after every milking
- Well-ventilated buildings (stack effect, outlet and inlet provision)
- Pre-milking teat disinfection
- “Living space” per cow
What 5 things can be done to prevent contagious mastitis spread in lactating cows?
- Prompt treatment of clinical mastitis events
- Antibiotic dry cow therapy for infected cows at the end of lactation
- Culling or segregating chronically infected cows
- Maintenance of the milking machine
- Post-milking teat disinfection
When is the mammary gland most likely to develop mastitis infections?
- before calving (transition) - colostro-genesis, reduced immune function, keratin plug breaks down
- after drying off (involution) - cisternal pressure, phagocytosis of fat cells, casein inhibits leucocytes
How can you prevent spread of environmental mastitis in dry cows?
- Clean bedding applied to any dry cow lying areas at least daily
- Bedded area per cow 1.25m2 per 1000 litres yield for loose yards
- Cleaning out calving pens between cows
- Cleaning any dry cow cubicles at least daily
- Well-ventilated buildings (stack effect, outlet and inlet provision)
- Aseptic infusion of dry cow therapy, esp. internal teat sealants
- Moving groups of dry cows every 2 weeks if managed at pasture
How can you recognise severe clinical mastitis?
- The cow will be systemically unwell
- Cow will be not eating
- Cow will be dull and may not present to the parlour
- Cow may even be “down” (i.e., recumbent)
What should you include in the clinical exam of a down cow?
What are 3 risk factors for severe clinical mastitis events?
- negative energy balance
- dry cow therapy in low cell count cow
- cow cell count
What is the treatment plan for severe clinical mastitis events?
- NSAIDS (IV or IV)
- fluids (hypertonic IV followed by oral fluids)
- Systemic antibiotics (broad spectrum)
- excellent nursing care
- supportive care (oxytocin and calcium)
How can we prevent severe clinical mastitis event?
- Environmental management at housing
- AIM: Reduce pathogen load and pathogen survival - Example = improve bedding management
- Reduce risk of opportunistic infection at key stages,
- Immune function support
- AIM: Avoid significant negative energy balance and excessive fat mobilisation around calving time - Example = avoid any constraint on dry matter intake (DMI)
- Improve neutrophil response to opportunistic infection…
- Supplements - Vitamin E and selenium
- Evidence that these improve white blood cell function
- Vaccination - “Startvac” (HIPRA) J5 core antigen vaccine
- Reduces risk of severe clinical mastitis events in dairy cows
