%0 Journal Article %T Conventional and extended intramammary therapy of persistent subclinical mastitis using nafcillin-penicillindihydrostreptomycin in lactating dairy cattle %J Iranian Journal of Veterinary Research %I Shiraz University %Z 1728-1997 %A Kasravi, R. %A Bolourchi, M. %A Farzaneh, N. %A Seifi, H. A. %A Barin, A. %A Hovareshti, P. %A Gharagozlou, F. %D 2011 %\ 06/01/2011 %V 12 %N 2 %P 113-120 %! Conventional and extended intramammary therapy of persistent subclinical mastitis using nafcillin-penicillindihydrostreptomycin in lactating dairy cattle %K Dairy cow %K Subclinical mastitis %K Extended therapy %R 10.22099/ijvr.2011.50 %X The objective of the present study was to compare the efficacy of conventional and extendedintramammary (IMM) therapy of persistent subclinical mastitis in lactating dairy cattle using nafcillinpenicillin-dihydrostreptomycin combination (NPD). Sixty-five dairy cows with 126 infected quarters were enrolled in the study. Infected cows were allocated randomly to 1 of 3 different treatment regimens: (1) conventional group: NPD administered IMM 3 times at 24-h intervals (20 infected cows, 43 intramammaryinfections [IMI]), (2) extended group: NPD administered IMM 6 times at 24-h intervals (23 cows, 43 IMI),and (3) untreated control group (22 cows, 40 IMI). The overall bacteriological cure (BC) rates for subclinicalIMI were 86.04%, 100%, and 20% for the conventional, extended and the control groups, respectively;indicating a higher BC rate (P<0.0001) for the treated groups than the control group. Significant difference(P=0.029) concerning the BC rate was also observed between the extended and the conventional groups.Significant difference (P=0.0021) in somatic cell count (SCC) was detected between the extended and thecontrol group. Fat percentage increased in the conventional (P=0.029) and in the extended (P<0.0001)groups, and protein percentage increased only in the extended group (P=0.0016). There was no significantdifference in posttreatment milk production between the groups (P>0.05). Results of this study indicate thatNPD therapy was effective in eliminating subclinical IMI in lactating dairy cows, and that extended therapyenhanced BC rate and reduced SCC. %U https://ijvr.shirazu.ac.ir/article_50_7117171e7a300135efbdb3611a160b46.pdf