[Attempts at time-related control of bovine hypodermiasis at scattered or grouped farms]

The control was performed by a unic systemic autumn treatment on heifers and repeated topical spring treatments on dairy cows. After a four years programme, limited success are obtained. No difference in the efficacy are observed in isolated or grouped farms. A good estimation of infestation cannot be obtained by only one or two numerations of warbles in spring. Repetitive of topical spring treatments on dairy cows appears to be the major limitating factor of success in these programmes.