The Mastitis Lab in Private Practice Brenda Moslock

The Mastitis Lab in Private Practice Brenda Moslock Carter, DVM Keseca Veterinary Clinic, PLLC P. O. Box 267, 1441 State Routes 5 & 20 Geneva, NY 14456 keseca@rochester. rr. com

Keseca’s in-house mastitis lab • Started in 2004 • Currently 2 technicians • Average ~450 cults/month (> 100/week) • Regularly participate in Lab Proficiency Program (QMPS)

Laboratory Services • Individual cow cultures – Clinical & subclinical (High SCC) cows – Aerobic cultures +/- Mycoplasma (can refer out) • Bulk tank cultures – Regular monitoring (screening for contagious bugs) – Quantitative analysis (trouble-shooting high bacterial counts)

Laboratory Services (contin’d) • Bedding cultures – Troubleshooting environmental mastitis • Towel cultures – Troubleshooting or routine monitoring • Colostrum & pasteurized waste milk – Monitoring hygiene +/- pasteurizer fnct – Troubleshooting calf health problems Quantitative analysis (“bacterial counts”)

Keys to success with inhouse mastitis culturing • Rapid turnaround & reporting of results (next-day preliminaries) • Dedicated person in charge • Provide “value added service” (specific treatment recommendations, consultation/ follow-up, monthly summaries for large herds, etc. )

Provide a value-added service

Herds are also given a sheet of personalized labels to put on sample vials

Individual cow samples Composite samples Only exceptions 1. Screening for mycoplasma or prototheca 2. Post-tx sample of Staph aureus cow Only exceptions: screening for Myco or Prototheca -or- post-treatment Staph aureus screening

So what do we need to start up a mastitis lab in our clinic?

Necessary Equipment • Incubator @ 37 o C • • • +/- another @ 32 o C for bulk tank cultures Bunsen burner or little propane torch Refrigerator for storing plates Freezer for storing samples Microscope Fluorescent & incandescent light sources

Incubator • 37 o (+/- 32 o) • Desktop model – Holds up to ~50 plates + tube rack – Used models < $100 • Check local dealers for used hospital equipment

t r a M lr a e n W r u e h B T sen n u B

• Desktop incubator @ 37 o C (~ $100 used) • Little propane torch ($45) üRefrigerator/freezer üMicroscope • Fluorescent & incandescent light sources ($15 each) Total capital investment < $200 (Assuming clinic already has a fridge/freezer and microscope)

Necessary Supplies • • • Sterile cotton swabs (or disposable loops) Wire loops (10 u. L) Disposable sterile plastic 1 ml pipettes Microscope slides +/- Graduated pipettes (if doing bacterial counts) • Tube rack

Basic Media & Reagents for NMC Method • • Blood agar plates Mac. Conkey plates Coagulase tubes Broth tubes Gram staining kit Hydrogen Peroxide Potassium Hydroxide

Misc. • System for tracking samples, recording & reporting results • NMC Handbook, other reference manuals • Good relationship with your local referral lab – Training – Phone support – Diagnostic support

Culture ® Tracker software • Developed by Dairy One in NY • Generates worksheet for lab techs • Final result sheet for client also shows cow’s prior culture history • Data can be exported to Excel for analysis

Results come with the cow’s history of previous cultures • Easy to identify chronic cows • If repeat quarter: is it the same bacteria (treatment failure) or a new infection? • Follow-up on Staph aureus cows Previous culture results Current culture result

Culture ® Tracker software • Results interface with Dairy Comp via Dairy One (uploaded to the LOOP) • Farm’s computer can be set to automatically download new results daily • Results automatically recorded in Dairy Comp or Scout v. Results recorded in a consistent manner Initial cost ~$250 Annual fee ~$275

Diagnostic Flowchart

“Strep species ” (i. e. “Strep non-ag”) • Strep dysgalactia (Strep dys) • Strep uberis • Lactococcus sp. – Lactococcus lactis • Aerococcus sp. • Enterococcus sp. May explain differences in response to treatment of “Strep species”

Differentiating Strep species light k c r Bla UV o Takes an additional day

“Esculin-Splitting” black light-vs-fluorescent light views (same 2 plates) black light Only 1 isolate is positive for “esculin-splitting” (gray/black-tint) standard lighting 3 out of 4 isolates “esculin-positive” (greenish-tint)

Mycoplasma Culturing • Requires special media & incubation conditions (CO 2 incubator) • Can be tricky to read (up to 7 days) • Whether or not you offer may depend upon prevalence in your area Alternative approach to Mycoplasma surveillance = referring out for pooled cultures

Pooling for Mycoplasma Surveillance Pros • Referral lab better equipped to handle, esp if in low-prevalence area • Cost-effective way to increase myco surveillance • May find it before it shows up in Bulk Tank cultures Cons • Myco susceptible to repeated freeze-thaw cycles & prolonged storage – May get more false-negs in low-cfu samples • Delayed turnaround if pool is pos – Need to wait for individual samples to be run • May not be available in all areas

Of the cases we culture in our practice: • ~1/3 are considered treatable Overall, we recommend treatment for • ~1/3 onlyare ~50%sometimes of the clinical cases we culture treatable Coliforms – (based on cow’s history & severity / amount of bacteria) • ~1/3 should not be treated – (sometimes because the bacteria are already gone!) Staph aureus Staph species Streps Staph species Yeast Prototheca Mycoplasma No Growth

Treatment Recommendations Intramammary Antibiotics: to Treat or not to Treat? Generally Treat Sometimes Treat Never Treat Strep ag Staph aureus* A pyo (Extended therapy) Strep dysgalactia Staph species (CNS Staph) Yeast Strep uberis* Coliforms Mycoplasma (Extended therapy) Influencing factors: - Chronicity (based upon SCC hx) - #cfu Prototheca “No growth” or “NSO”

The cost of over-treating: an extreme example this herd not only treated every clinical case, but they kept cows in treated group until CMT improved to cific d e ch n-spe t i Sw hoge t n pat atme tre

The dairy SOLD more milk/cow in 2006 despite producing ~2 lbs less per cow than in 2005