Some Investigations of Fly Control in Dairy Barns

Flies are such a serious pest to livestock that most stockmen make some effort to control them. On dairy farms, the problem is especially important due to the danger of contaminating milk. The United States Public Health Service has recognized the problem by prescribing regulations for approved dairy farms where Grade A milk is produced (18). Two general methods of control are usually recommended (3, 14): 1. elimination of breeding places, and 2. systematic killing of large numbers of flies. Frequent removal of manure by spreading it on field, elimination of stack bottoms, damp pries of feed or waste material together withutmost cleanliness inside the barn will greatly reduce the numbers of flies. On most farms more emphasis is placed on killing methods than the prevention of breeding. Killing methods include such recommendations as poison bait, traps, electric screens, spraying, or a combination of two or more such methods. Feeding drugs to cows to prevent flies from breeding in the droppings has even been tried Fans or water sprays on doors and other devices have been used to keep flies out of stables. Sprays either of the killing or repellent type keep flies out of stables, and are probably more universally used than any of the other systems of reducing fly numbers.