Efficacy of two antibiotic treatments in curing clinical and subclinical mastitis in lactating dairy cows
New Zealand Veterinary Journal 46(6): 226-232
595 cows with clinical or subclinical mastitis diagnosed between 8 July and 21 August 1997 in the Morrinsville region, New Zealand were used to evaluated the efficacy of 2 antibiotic treatments. 294 cows were treated (intramammary injection) with procaine penicillin at 0.5 g and dihydrostreptomycin at 0.5 g on 3 occasions at 12-h intervals (P-DHS) and 301 cows were treated with 2 s.c. injections of 10 and 5 gof penthamate hydriodide in aqueous solution (PEN) 24 h apart. Milk samples were collected before and 14 and 21 days after initiation of treatment for bacteriological culture, somatic cell count determination and conductivity testing. Streptococcus uberis was commonest isolate followed by coagulase-negative staphylococci, Staphylococcus aureus, Streptococcus dysgalactiae and coliforms. No significant differences in the bacteriological cure rate of major Gram-positive pathogens, clinical cure rate, somatic cell count or conductivity were found between treatments. However, the bacteriological cure rate of coagulase-negative Staphylococcus infections and the overall bacteriological cure rate was lower for quarters treated with PEN than with P-DHS.