Dr. Ron Erskine presented this information for DAIReXNET on Tuesday, February 12, 2013. For more information, please see our archived webinars page at www.extension.org/pages/15830/archived-dairy-cattle-webinars.

1. Better Milk Quality from
Better Mastitis Therapy Decisions
Dr. Ron Erskine, Michigan State University

2. 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

4. XXX
Alternative Therapies

5. Tanker loads with antibiotic residues have
decreased ………
• Has the amount of drug use changed ?
• Has the amount of Extra Label Drug Use
changed?

6. Antimicrobial Drug Use
106 doses/week/1,000 cows 100 doses/week/1,000 cows
Adult cows All animals
Survey Trash Collection
Pol and Ruegg, JDS, 90:2007 Saini et al, JDS, 95:1209, 2012

7. Extra Label Drug Use- IMM administration
20 Wisconsin dairy herds
• 11 Herds
 Ampicillin - 6 herds
 Ceftiofur - 3 herds
 Gentamicin- 3 herds
 Penicillin- 1 herd
 Miconazole- 1 herd
 Tetracycline- 1 herd
 Veterinary Magic Bullets- 2 herds
 Sulfamethoxazole/Trimethoprim – 2 herds
Pol and Ruegg JDS 90: 2007

8. 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?

9. Is AMR in mastitis pathogens emerging?
• ‘scientific evidence does not support a
widespread, emerging resistance among
mastitis pathogens to antibacterial drugs’

10. 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

11. Is antibacterial resistance in mastitis
pathogens emerging?
Temporal studies: same laboratory
S aureus Strep E. coli Coagulase
negative
staph
Mackie, et N/C ---- N/C ----
al. 1989 (coliforms)
Erskine, et N/C N/C N/C ----
al. 2002
Makovec Erythromycin N/C Erythromycin Lincomycin
and Ruegg, Lincomycin Pirlimycin
2003

12. 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

13. 2010 Inspector-generated Violations
900
Beef cows
800
Bob veal
700
Bulls
600 Dairy cows
500 Formula fed veal
400 Goat
300 Heavy calves
200 Heifers
100 Market hogs
Non-formula fed veal
0
Steers

14. 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

15. FDA Bulk Tank Sampling Program

16. Mastitis……..
• Largest cause of
antimicrobial drug
use in dairy cows

17. Antibiotics 101
 Concentration-dependent inhibition
 Magnitude above MIC enhances killing
• Peak serum > 10 times MIC
 Time-dependent inhibition
 Time above MIC, not peak concentration
• All labeled drugs for use in lactating
dairy cattle

18. 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)

19. 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)”

20. 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)

21. Is extended therapy right for you?
Depends on the herd

23. Concentration Milk:
Drug Plasma
Ceftiofur <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.

24. 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.

25. S. Nickerson

26. MILD CLINICAL MASTITIS
Culture
CHRONIC ???
Gram
Yeast, Pseudomonas, etc Coliforms Positive
No organism isolated
????
Administer IMM antibiotics
No antibiotic
treatment Records

27. 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%

28. Culture Based Therapy
Effects on lactation
Immediate Therapy Culture Based
Bacteriologic cure* 71 % 60%
Milk discard days* 5.9 5.2
Herd removal 28% 32%
Days at removal 160 137
Relapse of clinical 35 % 43 %
mastitis
Days at relapse 78 82
LSCC 4.2 4.4
* 21 days
Lago, et al JDS, 2011

29. SEVERE CLINICAL
MASTITIS
Fluids
Anti-Inflammatory
Culture
IMM and Systemic antibiotics
Coliforms Gram Positive
Continue antibiotics Continue IMM antibiotics
Supportive care
Unusual Pathogens (e.g.,
Pseudomonas, Prototheca)
No antibiotics, Supportive care

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