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

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.