Most insecticides used on beef animals also can be used on nonlactating dairy cattle, but there may be restrictions on time of treatment prior to freshening. Keep pesticides in original containers and in locked storage. Do not contaminate milk, feed or water when using an insecticide. Fly Control Sanitation. House, stable and blow flies may be pests of dairy cattle kept on lots.
Sanitation is the first and most important step in control of filth flies.
Clean cattle pens, drainage areas, loafing sheds, stalls, feeding aprons, spilled feed and other decaying organic matter at 10-day intervals to minimize fly breeding. If this decaying organic matter is spread on fields, spread it thin enough for rapid drying. The material can be spread in the lot and, when dry, incorporated into mounds or low spots within the lot. Take care to prevent moisture penetration in manure stored for later distribution. The manure stack should be steep-sloped and, if possible, packed.