Loss of animal feed due to infestation by Rhyzopertha dominica

Despite the use of natural food for livestock production, different animal feeds are currently available at the market. Long-term storage of these animal feeds lead to deterioration and contamination by insects. Therefore, it is important that the loss of these animal feeds be determined and methods to control the damage be sought. This study was conducted to determine the loss of eleven types of animal feed commonly used in Sri Lanka due to infestation by Rhyzopertha dominica, a major granivorous insect species. Twenty newly emerged adults of R. dominica were introduced separately to each animal feed: fish feed, rabbit feed, dog feed, cat feed, chick mash, grower mash, layer mash, broiler starter, broiler finisher, bird feed (Bajiri), and rice polish. Each animal feed was maintained either aerated or air tight. These parent adults were maintained for 21 days in the media under ambient environmental conditions (30°C, 65% relative humidity), and then removed. The progeny adults emerged in each feed sample were removed and the weight of the samples was determined at monthly intervals. In general, weight loss of animal feed varied with the feed type, duration of exposure, and aeration condition. Attention needs to be paid to protect those animal feeds that recorded higher losses due to R. dominica during storage.