EFFICACY OF POUR-ON AND INJECTABLE FORMULATIONS OF MOXIDECTIN AND IVERMECTIN IN CATTLE NATURALLY INFECTED WITH PSOROPTES OVIS - PARASITOLOGICAL, CLINICAL AND SEROLOGICAL DATA

On the basis of Psoroptes ovis counts performed on day -7, 32 animals were randomly allocated to a control group of five animals or to four groups comprising six or seven animals which were treated, respectivel y, with pour-on ivermectin (IPO), injectable ivermectin (II), pour-on moxidectin (MPO) and injectable moxidectin (IM). Living mites were cou nted in skin scrapings on days 0, 7, 14, 28, 42 and 56 post-treatment (PT). Lesions were recorded on a standardized map on days 0 and 56 PT. Antibody kinetics were studied using ELISA on serially diluted sera. The antibody titres were expressed as the dilution giving the positive /negative cut-off. Until their treatment on day 28, the control animal s remained parasitologically positive and their antibody titres increa sed. In treated groups, all living mite counts were negative on days 2 8 and 42 PT but some animals were still infected on days 7 and 14 PT. On day 56, living P. ovis were found in one animal of the IPO group. A n equation of regression describing the antibody decrease was calculat ed with each individual data set. In most of the treated animals, the coefficient of determination R-2, which describes the closeness of fit to the linear model, was above 0.9. The linear model could not be app lied (low R-2) to the antibody kinetics of four animals: the day 56 po sitive animal and its two neighbours in the IPO group and one animal f rom the MPO group. In the treated groups, the differences between the numbers of infected animals, the mean daily weight gains or the mean a ntibody titres were not statistically significant. Mean daily weight g ains of the treated groups were higher than in control animals. (C) 19 97 Elsevier Science B.V.