On- farm milk culture training workshop Chris-na 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 Wai-ng 24 hr to treat? No difference in long- term outcomes Recurrence Milk produc-on Risk for culling SCS Reduced an-microbial usage by 50% No change in cure rates 1
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 Three different selective medias Factor agar (proprietary ingredients) G+ only MTKT agar Streptococcus spp. only MacConkey agar G- only 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 2
Pla-ng on Tri- plates 1. Factor Agar (Bright red) Cow ID 3. MacConkey Agar (light pink) 2. Modified TKT (Dark red) 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 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 Strep spp. possible Staph spp. + + + 3
Identifying Staph aureus Factor agar + Staph aureus Factor Agar (red) Gram pos growth Staph/Strep On- farm culture results Streak in order of: Bright red (Factor Agar) Dark red (MTKT) Light pink (MacConkey) MTKT (Dark red) Grows Strep only MacConkey (pink) Gram neg growth E. coli/klebsiella Result + + - Strep or mixed Staph/ Strep + - - Staph (check hemolysis) - + - Strep - - + Gram- nega-ve (E. coli, Klebsiella, etc ) + + + Contaminated CNS versus Staph aureus Tri- plate alone doesn t give you a defini-ve answer Check hemolysis pa_erns Can do coagulase test if wanted Pos (+) = Staph aureus Neg (- ) = CNS 4
About the bugs Classifica-on Bacteria Source Control Staph CNS & Staph. hyicus Skin flora, subclinical Post dip, DCT Staph. aureus Infected udders Segrega-on, milking hygiene, treatment, cull About the bugs Classifica-on Bacteria Source Control Strep Env. strep & Enterococcus Strep. dys. Environment Environment and infected udders Pre & post dip DCT and clean environment Pre & post dip DCT and clean environment About the bugs Classifica-on 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 Serra7a Soil and plants Sand, clean & dry, pre dip, J5, no chlorhex. dip 5
Classifica-on Bacteria Source Control Other About the bugs C. bovis & other Coryneforms Yeast & Mold Prototheca Bacillus spp. T. pyogenes (formerly A. pyogenes) Infected udders, teat canal Soil, plants, water, cannulas, dirty infusions Soil, plants, water, manure, contagious Soil, water, wounds, dirty infusion Teat injuries, infec-ons Post dip, DCT Scrub teat ends well prior to infusion Segregate & cull cow, eliminate water areas Scrub teat ends well prior to infusion Fly control, killing affected quarter How to treat Classifica-on Bacteria Treatment Staph CNS & Staph hyicus Tx clinicals Today Don t tx subclin unless SCC DCT Staph. aureus Early lacta-on heifers 5-7d Pirsue Tx 2 nd, 3 rd lacta-on first -me cases Chronics unresponsive Occasional cure with DCT Cull chronics when feasible Culture fresh cows to monitor and tx Why are they hard to treat? 6
How to treat Classifica-on 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 Classifica-on Bacteria Treatment Coliform E. coli Local: No IMM treatment, Klebsiella Enterobacter suppor-ve therapy if necessary, infec-on 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 Serra7a Resistant to an-bio-cs, chronic infec-ons, open result in cull 180-300 ml hypertonic saline infused may help Extra label use - Spec-nomycin How to treat Classifica-on Bacteria Treatment Other C. bovis & Coryneform Yeast & mold Prototheca Bacillus spp. No lacta-ng treatment, DCT works No an-bio-c treatment, many spontaneously cure An-bio-cs do not work - cull Can cause similar signs as coliform infec-ons. Tx as gram- posi-ve Today or Pirsue T. pyogenes (formerly A. pyogenes) Kill the quarter or removal from the herd 7
Residues Follow label directions Treatment regiment Withholding time Test for antibiotic residue Want more info? Contact me milk@vt.edu or 540-231-4767 2014 Conference Sponsors Platinum Boehringer Ingelheim Vetmedica, Inc. Diamond V Merck Animal Health Virginia Tech Zoetis Gold Dairy Farmers of America, Inc. Dairy Records Management Systems Virginia Tech Dairy Extension W.D. Hoard & Sons Silver DeLaval Farm Credit of the Virginias Maryland/Virginia Milk Producers Cooperative Association, Inc. Virginia State Dairymen s Association Thank you for your support! 8