antibiotics, such as Aureomycin or Terramycin, would have to be used; these also can 
persist in milk longer than 3 days after intramammary infusion. * 
In addition, we should question the use of some of the penicillin products available 
for intramuscular injection of dairy cattle. Procaine penicillin G in oil and benzathine 
penicillin G and V in aqueous suspension may persist in milk for 6 days or longer after 
intramuscular injection with doses of 5,000 u./lb. of body weight (5 to 8 million units per 
cow) or higher. It would seem best, therefore, not to use these products in dairy cattle. 
Available data indicate that the sodium, potassium, diethylaminoethylester hydriodide, 
and procaine salts of penicillin G in aqueous suspension may last from 1 to 3-1/4 days at 
maximal doses of 10,000 u./lb. of body weight. Aureomycin, Terramycin, tetracycline, 
streptomycin, and most sulfonamides do not persist in milk longer than 2 days after 
parenteral injection of recommended doses. Consequently, by educationof the veterinarian 
and farmer these products can be used and not be a source of contamination of milk. 
The commonly used sulfonamides persist in milknolonger than 2 days after one oral 
dose, with the exception of sulfabromoethazine (3 days). In most instances, sulfonamides 
are given orally for several days, or one intravenous injection is given followed by 
several oral doses. More information, therefore, is needed on the persistence of sul- 
fonamides in milk after repeated dosing. 
We hope that this limited review will point the way for further research on the per- 
sistence of antibiotics and sulfonamides in milk. 
REFERENCES 
(1) Anonymous. 1960. Antibiotic residues in milk. Animal Disease Trends. 7(3): 1-2. 
(2) Barker, C.A.V., and Dussault, H. P. 1945. Observations on the permeability of the 
lactating bovine mammary glands to penicillin. Canad. J. Comp. Med. 9: 332-335. 
(3) Barnes, L. E. 1956. Oxytetracycline in bovine mastitis. II. Milk levels following 
local and parenteral administration. Amer. J. Vet. Res. 17: 18-23. 
(4) Bauer, H., and Gunderson, M. F. 1938. Para-aminosulfamidobenzene in amniotic 
fluid and placental blood. J.A.V.M.A. 93: 118. 
(5) Bell, W. B., Flora, C. C., Reaves, P. M., and Holdaway, C. W. 1951. Aureomycin 
concentration in milk following intramammary infusion and its effect on starter 
activity. J. Dairy Sci. 34: 675-679. 
(6) Bierlein, K. J. 1956. Repeated anaphylactic reactions in a patient highly sensitized 
to penicillin. Ann. Allergy 14: 35-40. 
(7) Boland, H. 1957. The new frontier in quality control. American Milk Review, Sept. 
(8) Boulton, W. D., Frazer, J. M., Cady, J. H., and Waller, E. F. 1949. Procaine 
penicillin G levels in udder during treatment of chronic mastitis. Vet. Med. 44: 
244-245, 
(9) Bradfield, A., Resi, L. A., and Johnstone, D. B. 1952. The presence of Aureomycin 
in milk and its effect on cheese making and starter activity. J. Dairy Sci. 35: 51- 
58. 
(10) Carmichael, J. 1949. The persistence of penicillin in milk. Vet. Rec. 61: 886. 
(11) Coleman, M., and Siegel, B. B. 1955. Studies in penicillin hypersensitivity. I. The 
significance of penicillin as a contaminant. J. Allergy 26: 253-261. 
199 
