WORM CONTROL PRACTICES ON SHEEP FARMS IN NYANDARUA DISTRICT OF KENYA

A questionnaire investigation was used to examine anthelmintic usage a nd practical worm control for sheep on 50 farms selected randomly in N yandarua District of Central Kenya. Control of helminths was based pri marily on the use of anthelmintics on all 50 farms. On the majority (5 4%) of these properties, lambs were drenched two times per year. Ewes and rams were drenched three or four times per year on 74% of the farm s. Most treatments were given at intervals of approximately 3 months w ith no specific drenching programmes. Anthelmintic doses for the sheep were based on weights estimated using visual appraisal on 98 and 96% of the properties for lambs and adult sheep, respectively. Only on a s mall proportion of the farms (22%) was the recommended weight of the h eaviest animal used when drenching groups of either lambs or adult she ep. In 1994, the majority (68%) of farmers used levamisole (LEV) in co mbination with oxyclosanide (OXY) a fasciolicide, 10% used benzimidazo les (BZs), 10% LEV alone and 12% LEV and BZs together. This pattern of anthelmintics use was maintained from 1988 to 1994. Eighty one percen t of the farmers had been using only LEV or BZs for three or more cons ecutive years from 1990 to 1994. The implications of these findings fo r the development of anthelmintic resistance are discussed. (C) 1997 E lsevier Science B.V.