On-farm milk culture training workshopsequalitymilk.com/wp-content/uploads/2015/11/On-farm...On-farm...
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On-farm milk culture training workshop Christina Petersson-Wolfe Department of Dairy Science Virginia Tech
Transcript of On-farm milk culture training workshopsequalitymilk.com/wp-content/uploads/2015/11/On-farm...On-farm...
On-farm milk culture training workshop
Christina Petersson-Wolfe
Department of Dairy Science
Virginia Tech
The right drug for the
right bug• Different bugs respond to different treatments
• Antibiotic sensitivities previously relied on
• Culture based therapy is best option
Waiting 24 hr to treat?
• No difference in long-term outcomes
– Recurrence
– Milk production
– Risk for culling
– SCS
• Reduced antimicrobial usage by 50%
• No change in cure rates
On-farm culture
• Various culture systems marketed
• Minnesota Bi-Plate and Tri-Plate most widely
used
– User guides printed in both English and Spanish
• Low initial input cost
– Incubator = $55
• Hova-Bator (egg incubator)
– Supplies = ~$2-3 per sample
On-farm culture
• Three different selective medias
– Factor agar (proprietary ingredients) – G+ only
– MTKT agar – Streptococcus spp. only
– MacConkey agar – G- only
On-farm culture
• Aseptically collect sample from clinical
quarter
• Use sterile cotton swab to streak on all 3
medias dipping back in sample between
• Incubate overnight and observe growth at
24 h
• Determine treatment
Plating on Tri-plates
1. Mix milk samples by inverting several times
2. Using aseptic technique uncap the tube of milk
3. Take a clean loop or swab and dip it into the tube
4. Starting with Factor Agar, streak milk sample from outside-in
following streak lines shown above
5. Repeat steps 1-3 and streak on Modified TKT agar
6. Repeat steps 1-3 and streak on MacConkey Agar
7. Cap milk sample and discard loop/swab
8. Incubate milk sample for 24 h at 37C
1. Factor Agar (Bright red)
2. Modified TKT(Dark red)
3. MacConkey Agar(light pink)
On-farm culture
• Gram positive growth = treatment
– Can determine Strep from other G+ and treat
differently if vet recommended
• < Gram neg growth = no treatment
• > Gram neg growth = systemic treatment
On-farm culture
• Strep spp. • possible Staph spp.
+ + +
On-farm culture
• Identifying Staph aureus
+
Factor agar
Staph aureus
On-farm culture resultsStreak in order of:
Bright red (Factor Agar)Dark red (MTKT)
Light pink (MacConkey)
Factor Agar (red)Gram pos growth
Staph/Strep
MTKT (Dark red)Grows Strep only
MacConkey (pink)Gram neg growthE. coli/Klebsiella
Result
+ + - Strep or mixed Staph/Strep
+ - - Staph (check hemolysis)
- + - Strep
- - + Gram-negative (E. coli, Klebsiella, etc…)
+ + + Contaminated
CNS versus Staph aureus
• Tri-plate alone doesn’t give you a definitive answer
• Check hemolysis patterns
• Can do coagulase test if wanted
– Pos (+) = Staph aureus
– Neg (-) = CNS
About the bugs…
Classification Bacteria Source Control
Staph CNS &
Staph. hyicus
Skin flora, subclinical Post dip, DCT
Staph. aureus Infected udders Segregation, milking hygiene, treatment, cull
About the bugs…
Classification Bacteria Source Control
Strep Env. strep &
Enterococcus
Environment Pre & post dip
DCT and clean environment
Strep. dys. Environment and infected udders
Pre & post dip
DCT and clean environment
About the bugs…
Classification Bacteria Source Control
Coliform E. coli Bedding, manure, soil
Sand, clean & dry, pre dip, J5
Klebsiella Organic bedding Avoid sawdust & recycled manure,
clean & dry
Enterobacter Bedding, manure, soil
Sand, clean & dry, pre dip, J5
Serratia Soil and plants Sand, clean & dry, pre dip, J5, no chlorhex. dip
How to treat…Classification Bacteria Treatment
Staph CNS & Staph hyicus
Tx clinicals – Today
Don’t tx subclin unless SCC
DCT
Staph. aureus Early lactation heifers – 5-7d Pirsue
Tx 2nd, 3rd lactation first time cases
Chronics unresponsive
Occasional cure with DCT
Cull chronics when feasible
Culture fresh cows to monitor and tx
Why are they hard to treat?
How to treat…Classification Bacteria Treatment
Strep Env. strep. & Enterococcus
4-5 d penicillin -
(3.5cc/100 lbs BW systemically)
Good cure with DCT
Strep. dys. Label treatment with Today
Good cure with DCT
How to treat…
Classification Bacteria Treatment
Coliform E. coli Local: No IMM treatment, supportive therapy if necessary,
infection typically clears in < 10 days
Systemic: IV Fluids (2-3L saline), followed with oral, Banamine (20cc
on sick big Holsteins),
60-80 cc Oxytet IV
Klebsiella
Enterobacter
Serratia Resistant to antibiotics, chronic infections, often result in cull
180-300 ml hypertonic saline infused may help
Extra label use - Spectinomycin
Residues• Follow label directions
– Treatment regiment
– Withholding time
• Test for antibiotic residue
2015 Conference Sponsors
PlatinumMultimin USA
Zoetis
Gold
Elanco
Maryland-Virginia Producers
Cooperative Association
DFA– Mid-East
DFA– Southeast
W.D. Hoard & Sons
Silver
CPC Commodities
Kentucky Dairy
Development Council
Thank you for your support!
Contributor
Bluegrass Dairy and
Food, Inc.
