[Recent data on the treatment of bovine hypodermyiasis using metrifonate (Neguvon) and ivermectin (Ivomec) in...

Large scale preventive treatments against bovine hypodermosis have been performed in the Canton of Grisons and in different Jura areas. Either Metrifonate (Neguvon 10% spot-on, Bayer AG) or Ivermectin "microdoses" (i.e. 0.1 ml Ivomec ad. inj-MSD AGVET-per animal) have been applied. The treatment of dairy cows with Neguvon at the then recommended dose (24 ml/animal) showed a low efficacy of 80%, without any correlation to the date of treatment. An increase of the dose to 36 ml/animal revealed an efficacy of 93%, while a weight-dependent dose of 6 ml/100 kg body weight reduced the warble infestation by 97.3% without any drug-related side-effects. The few observed side-effects-salivation and mild meteorism--are likely to be due to the destruction of Hypoderma lineatum larvae in the gullet of treated cows. No case of abortion was reported. The Ivomec--"microdose" applied to young animals or dry cows showed an efficacy > 99.8%. The available drugs would thus allow a quick and efficacious control of bovine hypodermosis, provided they would be used systematically and at an appropriate dose in endemic areas.