Better Milk Quality from Better Mastitis Therapy Decisions

Dr. Ron Erskine, Michigan State University

Mammitis: Inflammation of the Bag

Treatment : Prevention•Bichloride of Mercury, 2 grains

•Boracic Acid, 2 drams•q.s. One quart water, intramammary infusion

CJ Korinek, The Veterinarian, 1915

Alternative Therapies X X X

Tanker loads with antibiotic residues have decreased ………

• Has the amount of drug use changed ?

• Has the amount of Extra Label Drug Use changed?

Antimicrobial Drug Use

106 doses/week/1,000 cowsAdult cowsSurvey

Pol and Ruegg, JDS, 90:2007

100 doses/week/1,000 cowsAll animalsTrash Collection

Saini et al, JDS, 95:1209, 2012

Extra Label Drug Use- IMM administration20 Wisconsin dairy herds

• 11 HerdsAmpicillin - 6 herdsCeftiofur - 3 herdsGentamicin- 3 herdsPenicillin- 1 herdMiconazole- 1 herdTetracycline- 1 herdVeterinary Magic Bullets- 2 herdsSulfamethoxazole/Trimethoprim – 2

herds Pol and Ruegg JDS 90: 2007

Implications for failure of therapy

• “Drugs just don’t work the way they use to……”• Antimicrobial resistance ? • Limited drugs for use in dairy cattle ?• Immune stress ?• Higher milk production?

Is AMR in mastitis pathogens emerging?

• ‘scientific evidence does not support a widespread, emerging resistance among mastitis pathogens to antibacterial drugs’

AMR in mastitis pathogens emerging ?

• Staph aureus

• 50 to 60% of S aureus isolates resistant to unprotected β-lactam drugs • Numerous studies • Forty years• No evidence of any change

Is antibacterial resistance in mastitis pathogens emerging?Temporal studies: same laboratory

S aureus Strep E. coli Coagulase negative staph

Mackie, et al. 1989

N/C ---- N/C (coliforms)

----

Erskine, et al. 2002

N/C N/C N/C ----

Makovec and Ruegg, 2003

ErythromycinLincomycin

N/C Erythromycin LincomycinPirlimycin

US National Residue Program -2010

• Kidney Inhibition Swab test or Fast Antimicrobial Screen Test

• 211,733 Inspector Generated Samples• 7,000 positive samples• 2,043 confirmed violative residues (1,609

animals)

2012 Residue Sampling Plans, USDA FSIS

2010 Inspector-generated Violations

Series10

100

200

300

400

500

600

700

800

900

Beef cowsBob vealBullsDairy cowsFormula fed vealGoatHeavy calvesHeifersMarket hogsNon-formula fed vealSteers

FDA Survey

• The long-anticipated drug-residue-sampling survey by the U.S. Food and Drug Administration has begun.

• 900 milk samples from dairy farms had a cull dairy cow residue violation

• 900 milk samples from dairies at large.• 26 different drugs

Dairy Herd Network, Jan 10, 2012

FDA Bulk Tank Sampling Program

Mastitis……..

• Largest cause of antimicrobial drug use in dairy cows

Antibiotics 101

Concentration-dependent inhibition Magnitude above MIC enhances killing

• Peak serum > 10 times MIC

Time-dependent inhibitionTime above MIC, not peak concentration

• All labeled drugs for use in lactating dairy cattle

Antibiotics 101

Dose intervals-• Holstein calves treated with chloramphenicol 4x more likely to die if treated once per day as opposed to twice per day (Waltner-Toews, Can Vet J, 1986)

Duration• 2 days after clinical and microbiological resolution, severe cases: 7-10 days, chronic: may involve months (Giguere, et al. Antimicrobial Therapy in Veterinary Medicine, 4th edition, 2006, pg 113)

Ampicillin Trihydrate (Polyflex)

“3 days treatment is usually adequate, but treatment should be continued for 48 to 72 hours after the animal has become afebrile (up to 7 days)”

Extended mastitis therapy :subclinical mastitis

• 125 mg ceftiofur cure rates• 10 % : control • 39 % : 2 days• 54 % : 5 days• 66 % : 8 days

• Staph aureus 36%• Strep uberis 67%• Strep dysgalactiae 80 %• CNS 86 %

(Oliver, et al, JDS, 2004)

Is extended therapy right for you?Depends on the herd

DrugConcentration Milk:

PlasmaCeftiofur <1%Sulfadimethoxine 18%Penicillin 19%Ampicillin 27%Spectinomycin 75% Tetracycline 140%Tylosin 250% Lincomycin 450%Erythromycin 650%

Adapted from Langston, Antimicrobial Use in Food Animals, in Howard & Smith ed., Current Veterinary Therapy food animal practice, IV.

Making Better Therapeutic Choices

• Repeat Offenders• Duration of infection• Lactation• Higher SCC • Multiple infected quarters

• Non-responsive pathogens• Mycotic organisms (Candida), Prototheca,

Pseudomonas, Mycoplasma, Serratia, Nocardia, Proteus, Pasteurella, etc.

S. Nickerson

MILD CLINICAL MASTITIS

Culture

ColiformsYeast, Pseudomonas, etcNo organism isolated

Gram Positive

CHRONIC ???

No antibiotic treatment

Administer IMM antibiotics

Records

????

Culture based therapy

• 3,500 cow dairy - MI (Hess et al, 2003)• Reduced days withheld by 80%• Two full time veterinarians• Laboratory

• 4 herd study - SD and MI (Wagner, et al, 2007)• Bacteriology skills highly variable among herds

• 8 herd study - MN, WI, ON ( Lago et el, JDS, 2011) • Reduced antibiotic use 50%

Culture Based TherapyEffects on lactation

Immediate Therapy Culture BasedBacteriologic cure* 71 % 60%Milk discard days* 5.9 5.2Herd removal 28% 32%Days at removal 160 137 Relapse of clinical mastitis

35 % 43 %

Days at relapse 78 82LSCC 4.2 4.4

Lago, et al JDS, 2011* 21 days

SEVERE CLINICAL MASTITIS

Culture

FluidsAnti-InflammatoryIMM and Systemic antibiotics

Gram PositiveContinue IMM antibiotics

Unusual Pathogens (e.g., Pseudomonas, Prototheca)No antibiotics, Supportive care

ColiformsContinue antibioticsSupportive care

It’s not the drugs…….it’s how we use them!