Comparative Effectiveness of Different Dry Cow Treatment Systems

Abstract

 The practice of treating cows for mastitis at drying off is usually traced to the work of Pearson (23,24) in 1950. However, the practice was used as early as 1938 by Johnson (11) who administered acriflavin at drying off. Schalm and Ormsbee (39) also experienced success prior to 1950.

Pearson resorted to treatment at drying off in an effort to find a suitable method for preventing "summer mastitis" caused by infections with Corynebacterium pyogenes during the dry period. He reported that use of an aqueous suspension of sodium penicillin did not protect the udder against C. pyogenes infection because the drug persisted in the gland for only a few days. Subsequent trials with penicillin in oil reduced the incidence of dry period infections 47%, while the addition of aluminum monostearate to the mixture yielded a prophylactic value of 75% because of longer drug persistency. Johnson's acriflavin therapy was particularly successful against Streptococcus agalactiae infections. Schalm and Ormsbee reported cure rates against Staphylococcus aureus of 20.3 and 52.8%, respectively, when treatments were administered during lactation and the dry period. Thus, dry cow therapy provides both prophylactic and therapeutic benefits. Specific advantages are:

-higher persistency products can be used
-drugs are not eliminated from the udder by milking
-damaged tissue may be regenerated
-saleable milk is not contaminated with drug residues
-clinical mastitis is reduced at parturition.