Efficacy of levamisole pour-on compared with levamisole subcutaneous injection against Dictyocaulus viviparus infection in calves.

The efficacy of levamisole pour-on against Dictyocaulus viviparus was compared to that of subcutaneous levamisole injection. Eighteen calves were raised individually and artifically infected with D. viviparus larvae. Faecal samples were collected 27 and 28 days later and larvae per gram (l.p.g.) determined. The animals were then divided into three comparable groups. Group 1 animals remained untreated as controls. Group 2 animals received levamisole 10% w/v subcutaneous injection at a dose of 5 mg kg-1 and Group 3 received levamisole pour-on 20% w/v at a rate of 10 mg kg-1 applied transdermally. Results of l.p.g. measurements from faecal samples taken 7 and 8 days post-treatment indicated a dramatic reduction in the worm burden of animals in both treatment groups. Necropsies at 14 days post-treatment revealed few adult worms in these groups, indicating a 99 and 98% kill rate for pouron and subcutaneous injection, respectively.