الكاتب: Multiple References

Ziv, G. 8c Storper, hl. Intramuscular treatment of subclinical staphylocorcal mastitis in lactating cows with penicillin G, methicillin and their esters. J. uel. Plzarniacol. Therup. 8, 276-283. The relationship between antibiotic milk concentrations and hactei.iological efficacy was investigated in groups of lactating cows with sulxlinical mastitis due to either penicillin G-sensitive or penicillin G-resistant Staklrylococcco. (iureio.. Treatments consisted of the intraniuscular injection of procaine penicillin C;, or its weak base ester penethamate hyclriodide, and sodium methicillin, or its weak base ester tamethicillin. Antibiotics were administered once daily lor 2 or 4 clays at accepted dosages. After four daily, treatments with procaine penicillin G and penetli;uiiate hydriodide, infections were eliminated From 56.5% mid 68.8%. respectively, of quarters infected with penicillin G-sensitive staphylococci. and from 14.3% and 7.7%. respectively, of quarters infected with penicillin G-resistant staphylococci. After Four daily treatments with sodium methicillin and tamethicillin, infections were eliminated from 32.4% and 48.6%. respectively, of quarters infected with penicillin G-resistant staphylococci. The better ef'licacy of penethamate hydriodide and tamethicillin was considered to be linked to the higher milk drug concentrations obtained with these drugs as opposed to the lower concentrations measured in the milk after treatment with the parent drugs. Cure rates were generally higher after treatment for 4 days than after the 2-day course of therapy. Treatment efficacy decreased progressively with increasing age of the Intramuscular treatment of subclinical staphylococcal mastitis in lactating cows can serve as a useful model for screening existing and new antibacterial agents and drug products intended for the parenteral treatment of clinical staphylococcal mastitis.