Efficacy of deltamethrin pour-on (BUTOX® 7.5 Pour-On) against Haematopinus tuberculatus in Italian Mediterranean buffalo (Bubalus bubalis)

Introduction - The sucking louse Haematopinus tuberculatus is a harmful ectoparasite found on water buffalo (Bubalus bubalis). Louse infestation often leads to skin irritation, anemia, anorexia, restlessness and reduced productivity. Specific treatments for lice control are uncommon throughout the world; however, deltamethrin is used to control ectoparasites in farm animals and is considered the most effective among synthetic pyrethroids. Aims - The present paper reports the results of a field trial conducted in two buffalo farms in southern Italy to assess the efficacy of deltamethrin pour-on against the sucking louse H. tuberculatus and the influence of treatment on milk yield. Materials and methods - The trial was conducted between March and September 2016. The parasitological investigation was performed on 45 lactating buffaloes, 15 belonging to the Control Group, 15 belonging to the DELTA 1 Group (treated with deltamethrin pour-on at the dosage of 75 mg/head) and 15 belonging to DELTA 2 Group (treated with deltamethrin pour-on at the dosage of 150 mg/head). The groups were homogeneous for number of lice, age and milk production. Louse counts were performed on days -1, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77 and 84 at thirteen predilection sites on the skin of each buffalo. Statistical analysis was performed using ANOVA one way test, by Graphpad Prism 5. Results and discussion - In terms of percent lice reduction, deltamethrin pour-on was highly effective in DELTA 1 Group (100% in farm no. 1 and 99.1% in farm no. 2) and 100% in DELTA 2 Group (in both farms). A significantly (P<0.05) higher milk yield was recorded in both treated groups (DELTA 1 and DELTA 2) compared to the control group. No differences were observed between the two groups. During the trial, deltamethrin was well tolerated by all animals, demonstrating an optimal tolerability of the drug in the buffalo species. Conclusions - The availability of deltamethrin in a pour-on formulation for buffaloes during the lactating stage would be highly beneficial to buffalo farmers who derive an important part of their income from buffalo milk.