Mastitis: Therapies Flashcards
Why is dry cow therapy used?
Clear persistent infections
* Sub clinical
* Staph-aureus- intracellular
* High cell counts
Protect against new infections
* Acute E coli
* Summer mastitis
What pathogen causes summer mastitis with:
1. Necrosis
2. Foul smell
How is summer mastitis managed?
- Arcanobacter pyogenes
- Peptococcus indolicus
Pyrethrin pour on- flies
What are the disadvantages of dry cow therapy?
- Lower cell count
- New infections from poor hygiene
- Spectrum required to protect against enterobacteriaecae
- Cost
- Consumer pressure
- Farm assurance schemes
What is selective dry cow therapy?
- Teat sealant only to some cows
- Used with AB tubes based of bulk milk, mastitis incidence, outbreak type
What are teat sealants made from?
How do they work?
4g suspension containing 65% bismuth subnitrate
Remains as a paste within the base of the teat cistern and teat canal until stripped at calving
What cows should be selected for selective dry cow therapy?
SCC
* > 200,000
* > 125,000- first lactation
* Clinical case
* CaliMT before drying off
* Check teat ends- damaged AB?
What are the problems with teat sealants?
Black spots in cheese
* Bismuth subnitrate and hydrogen sulphide
Risk of infection with poor hygiene
Describe intra-mammary tube application
- After milking and cleaning of parlour
- Clean gloves
- Pre-dip- 30s
- Surgical spirit and cotton wool
- Clean teat end until no more dirt
- Insert and deposit
- Post dip- some repeat sailt
- Loafing 30min
- Feed restriction- reduce milk production
How is formulation of AB dry tubes varied?
What difference does it make?
- Type of AB
- Salt of AB
- Particle size
- Short duration- short dry period or repeat treatments
- Standard
- Extended protection
How should AB tubes be selected?
What are common combinations of ABs?
Target staph then broaden out
- Cloxacillin ± Ampicillin
- Penicillin ± framycetin ± penethamate,
- Cephalosporins- critically important (C&S)
What are the milk times after calving of AB dry cow tubes?
- Usually 96h post calving
- Some 156
- Some 24
Influence of other conditions- milking frequency, milk fever
What other treatments can cow recieve at drying off?
Other then mammary tubes
- Tylosin
- Tilmicosin
Authorised for pneumonia in beef
* Draxxin
* Zactran
* Zuprevo
Why do not all mastitis cases need treating?
- Culture negative
- Yeast
- Self cure
What can cause mastitis treatment failure?
- AB resistance
- Bacterial dormancy (treatment duration- 10 life cycles)
- L-forms
- Biofilms
- Reduced host response- steroids, stress
- Reduced phagocytosis
- Re-infections
- ABs problem- too low, too long dose interval, too short tx period
- Pharmacokinetic limitations- absorption, disposition, elimination
Does E.coli need AB therapy?
Likely to be self-resolving
