Mastitis therapeutics Flashcards
Does mastitis self-cure?
Depends on type of bacteria
Not treating mild cases due to gram negative organisms now being advocated
Which drugs can be given to reduce bacterial counts in the udder?
Oxytocin
Antibiotics
Why can dry cow neglect occur?
- Does not make farmers money
- Can set the farmer up to lose money
- Dry period is the time to set the cow up for a successful lactation
How long is a typical dry period?
60 days
- consider shorter if worried about drying off at high yields
What is Xtra in Bovaclox Xtra that isn’t in Bovaclox ?
600 mg Cloxacillin vs 500 mg
300 mg Ampicillin vs 250 mg
Is this the same “Xtra” that is in Orbenin Xtra but not in Orbenin ?
NO –no Ampicillin in either Orbenin
But still 600 mg Cloxacillin vs 500 mg
When do 50% of clinical mastitis cases occur due to acute enterobacteriae?
In the first 100 days acquired during the dry period
How is summer mastitis managed?
Fly management - pyrethrin pour-on
Describe selective dry cow therapy
Teat sealant only to some cows
Can also be used in combination with antibiotic tubes
Which products can be used for selective dry cow therapy
Orbeseal
Boviseal
Ubroseal Blue - includes a blue dye
Noroseal - includes Povidone iodine
How does Orbeseal work?
Remains as a paste within the base of the teat cistern and teat canal until stripped out at calving
Remain in situ for the entire length of the dry period even in dry periods of up to 100 days
How can you select which cows are treated with dry cow therapy?
- Bacteriology
- SCC
- California mastitis test before drying off
What must be ensured when administering dry cow therapy?
Needs to be sterile
If not sterile then cows will get sick (and could die!) a few days after infusion
How can teat sealants affect milk products?
Black spots in cheese
Bismuth subnitrate + hydrogen sulphide
from maturing cheese = bismuth sulphide
What cows in a herd would you select for dry cow therapy?
L low threshold of last somatic cell count
No recent history of mastitis
Good health and no teat damage
Before drying off, how can you check that a cow is still suitable for dry cow therapy?
Milk can be tested the day before drying off with a California mastitis test to ensure the cow has not become infected since the last recording.
What are the legal requirements for antibiotic dry cow therapy usage
Must be prescribed by the practicing vet based on the individual animal and be supported by an appropriate diagnostic test
Describe an appropriate protocol for preparation of intra-mammary tube application
Hygiene vital
- Do after milking and cleaning of parlour
- Clean gloves, washed between cows
- Pre-dip and allow kill time of 30 secs+
- Loads of surgical spirit and cotton wool
- Clean teat end until no more comes off
- Get a new bit of cotton wool and do it again!
Describe an appropriate protocol for application of an intra-mammary tube
- Teat order - Back then front then treat front to back?
- Nozzle design - teat penetration may damage canal seal – short nozzle only in tip of teat?
- Post dip: some repeat dip daily
- Barrier external teat sealant?
- Loafing for 30 min
- Re-check daily
- Feed restriction to reduce milk production
- Dry cow management – do not neglect
What is the aim of products used intra-mammary?
Short duration products
- short dry period or repeat treatments
- MC tubes
- 33 days now minimum
What is the issue of the product having too short of a duration?
Risk of re-infection
What is the issue of the product having too long of a duration?
If they calve early - discard milk or bulk milk fail
What are the milk witholds after calving following dry cow therapy?
Usually 96 hour post calving milk withhold
Some now extended 156 hours
What are the meat witholds after calving following dry cow therapy?
10 - 30 days - most 28 days
How can drying off be appropriately managed?
- Set dry period: management decision - early / late
- Batch dry off: get organised, identify cow, less mistakes
- Abrupt: intermittent milking - cell counts increase
- Cow should not go through parlour again -> milk let down = risk of antibiotic in milk
List some other drugs that may be given at drying off?
Tylosin
Tilmicosin
Other longer acting Macrolides
Why do you not need to treat all mastitis cases?
Some culture negative
Some due to yeast
Some will self-cure
Some farms using on farm culture systems and not treating mild gram –ve infections during lactation
List the reasons that mastitis treatments fail
- Antibiotic resistance
- Bacterial dormancy
- L-forms
- Biofilms
- Reduced host response: steroids, stress
- Reduced phagocytosis
- Re-infections
Why do L-forms lead to mastitis treatment failure?
Insensitive to beta-lactams
AB’s may not reach the site of infection in adequate concentrations due to what factors?
- Too low a dose
- Too long a dose interval
- Too short a treatment period
List some pharmacokinetic limitations that can lead to mastitis treatment failures
- Absorption, disposition, elimination
- Sequestration due to ionisation (pH trap)
- Diffusion barriers in intramammary treatment (oedema, blocked ducts, abscesses, fibrosis)
- Poor delivery of AB across blood/milk barrier in parenteral treatment
- Binding of AB to milk or serum protein
- Intracellular parasitism
How can milking cow therapy be administered?
Intramammary
Systemic
Both
How can you broaden antibiotic spectrums?
Use combinations of antibiotics
Where do you want the antibiotic to target for staphylococcus aureus
Some to milk/ducts
Mostly to udder tissue
Where do you want the antibiotic to target for coliforms
Some into milk/ducts
Mostly systemically
Where do you want the antibiotic to target for Streptococcus agalactiae?
All to milk/ducts
List some antibiotics that get to the site via the teat well
Macrolides
Phenicols
Fluoroquinolones
Penthamate
Aminopenicillins
Which antibiotic doesn’t reach the site well via the teat?
Streptomycin
Orbenin in LA contains which AB?
Cloxacillin
Synulox contains which drugs?
Amoxicillin and Prednisolone
Name two licenced combinations that cab be used as injections and in tubes
Cobactan
Synulox
Describe why pain relief is given to mastitis cases
Increased sensitivity to touch, hyperalgesia, increased kicking, increased heart, respiratory rate, and rectal temp
NSAIDS also anti-endotoxic
Eat more, milk more, recover better
Name some current NSAID options for cattle
Flunixin meglamine
Ketoprofen
Meloxicam
Carprofen
Aspirin - Not for use in animals producing milk for human consumption
What are the factors involved which determine the change of mastitis treatment success
How chronic?
History – cases this lactation, quarter SSC, palpation
Organism isolated
Age of animal
Stage of lactation
Concurrent diseases
How would you treat the following mastitis case:
- Young, first case this lactation, high SCC previous month
IM (+ systemic)
How would you treat the following mastitis case:
End of lactation, high SCC
Dry off and treat with dry cow therapy (+/- systemic)
How would you treat the following mastitis case: Old and 3rd case this lactation, chronic high SCC
Cull
How would you treat the following mastitis case: Young, first case, low SCC previous month
No treatment - watchful waiting
How can you prevent mastitis?
- Remove predisposing factors
- Milking machine
- Environment for lactating and dry cows
- or re-infection is inevitable - Sources of infection:
- Environment
- Cows
- Quarantine / test new stock
- Records = cull / treatment policy
- Quarter cell counts
- Clinical cases per lactation
