Field Efficacy of Moxidectin 0.5% Pour-on against Chorioptes Bovis, Damalinia Bovis, Linognathus Vituli and Psoroptes Ovis in Naturally Infected Cattle

Field efficacy of a pour-on formulation of moxidectin, a macrocyclic lactone endectocide, was evaluated in cattle naturally infested with Chorioptes bovis, Damalinia bovis, Linognathus vituli and Psoroptes ovis. In trial 1, two experimental groups of cattle naturally infested with P. ovis were formed. Group 1 animals remained as untreated controls whereas Group 2 animals were treated on day 0 with 0.5% moxidectin cattle pour-on at a dose of 0.5 mg kg-1 bw. Efficacy was assessed by (a) taking skin samples from each animal on days -4, 7, 14, 21, 28, 42 and 56 post treatment (PT) and observing the numbers of viable P. ovis mites and (b) clinical examination of animals on days 7, 14, 21, 28, 42 and 56 with the percentage of affected body surface calculated and live body weights recorded for each animal on days 4, 28 and 42. The pour-on formulation of moxidectin yielded excellent efficacy as no live mites were found in treated animals at 14, 21, 28, 42 and 56 days PT, except in one animal from which one adult mite was collected on day 42. Clinical indices showed a regular decrease in the affected body surface area. All untreated animals but one remained positive until day 28 and their clinical condition worsened rapidly. In trial 2, two experimental groups of cattle naturally infested with D. bovis and L. vituli were selected. Group 1 remained as untreated controls whereas Group 2 individuals were treated on day 0 with 0.5% moxidectin cattle pour-on at a dose of 0.5 mg kg-1 bw. Efficacy was assessed by identifying and counting lice on eight 15 cm hair partings at predefined anatomical sites on days 0, 14, 28 and 42. On the basis of animals cured and lice count reduction, efficacies were 100% on day 14 and from then onwards for both species. In trial 3, 24 animals naturally infested with C. bovis were divided into three experimental groups comprising eight (Group I), seven (Group 2) and nine animals (Group 3). Group 1 was the untreated control group whereas Groups 2 and 3 animals were treated on day 0 with 0.5% moxidectin cattle pour-on at a dose of 0.25 mg and 0.5 mg kg-1 bw, respectively. Efficacy was assessed as in trial 1. Skin scrapings were collected on days -3, 7, 14, 28, 42 and 56 PT. A clinical index was calculated for each animal on days 0, 28 and 56 whereas body weights were recorded on days 0 and 56. At 0.25 mg kg-1 bw, the efficacy of moxidectin cattle pour-on against C. bovis was incomplete. In contrast, at a dose of 0.5 mg kg-1 bw, moxidectin cattle pour-on was fully effective and by day 14 PT all animals were negative for C. bovis and remained so until the end of the trial. No side effects were observed during these three trials. These results indicate that at a dose of 0.5 mg kg-1 bw, the pour-on formulation of moxidectin is highly effective against C. bovis, D. bovis, L. vituli and P. ovis

Eléments du diagnostic des parasitoses externes des ruminants

peer reviewe

Field Efficacy of Injectable and Pour-on Moxidectin in Cattle Naturally Infested with Psoroptes Ovis (Acarina: Psoroptidae)

Field efficacy of moxidectin, a macrocyclic lactone endectocide, was evaluated in cattle naturally infested with Psoroptes ovis. Three groups of six animals were used based on parasitological and clinical status. Group 1 animals received one subcutaneous injection of injectable moxidectin at 0.2 mg kg-1 body weight; Group 2 animals received topically one dose of 0.5 mg kg-1 body weight of pour-on moxidectin; Group 3 individuals remained untreated as controls. Efficacy was assessed by (a) taking skin samples from each animal on Days -4, 14, 28, 42 and 56 post-treatment (PT) and observing numbers of viable mite stages and species and (b) clinical examination of animals on Days 14, 28, 42 and 56 with the percentage of affected body surface calculated for each animal on Days -4, 28 and 56. Both formulations gave 100% efficacy as no live mites were found in Groups 1 or 2, 14, 28 and 56 days after treatment. Clinical indices showed a sharp decrease in the affected body surface area from a mean of 5.48% and 6.1% on Day -4 in Groups 1 and 2, respectively, to 0% in both groups on Days 28 and 56 PT. All untreated animals remained positive until Day 28. The clinical condition of the controls worsened rapidly during the experiment (mean clinical index: 2.87% and 13.05% on Days -4 and 28, respectively) and they were given an emergency treatment on Day 28. No side-effects were observed with either formulation.(ABSTRACT TRUNCATED AT 250 WORDS

Field Efficacy of Injectable Moxidectin in Cattle Naturally Infested with Chorioptes Bovis and Sarcoptes Scabiei

peer reviewedField efficacy of moxidectin, a macrocyclic lactone endectocide, was evaluated in cattle naturally infested with Chorioptes bovis and Sarcoptes scabiei. Eight animals were allocated to two groups of four animals each, based on parasitological and clinical status. Animals of the treated group received one subcutaneous injection of injectable moxidectin at 0.2 mg kg-1 body weight on Day 0. Individuals of the control group received emergency treatment of a single injection of moxidectin at 0.2 mg kg-1 body weight on Day 28. Efficacy was assessed by (a) taking skin samples from each animal on Days 0, 7, 14, 21, 28, 42 and 56 and observing the numbers of viable mite stages and species and (b) clinical examination of animals on Days 7, 14, 21, 28, 42 and 56 with the percentage of affected body surface calculated for each animal on Days 0, 28 and 56. On the basis of the geometric means from treated and control animals, the percentage reductions in the total numbers of living C. bovis mites on Days 7, 14, 21 and 28 were 69, 87, more than 99 and 98, respectively. However, at the end of the trial, only two animals were negative for C. bovis. The percentage reductions in the total numbers of S. scabiei on Days 7, 14, 21 and 28 were 93, 100, 100 and 100, respectively. Clinical indices of the treated animals showed a sharp decrease in the affected body surface area from a mean of 43.6% on Day 0 to 0.9% and 0% on Days 28 and 56, respectively.(ABSTRACT TRUNCATED AT 250 WORDS