The Insect-Free Cattle Dropping and Its Relationship to Increased Dung Fouling of Rangeland Pastures

Natural and experimentally formed dung pads dropped on range in May and early June totally smothered covered forage during the first year. However, the invasion and feeding activity of hundreds of Aphodius fimetarius (L.) (Coleoptera: Scarabaeidae) adults in many such pads, plus annual fall rains, resulted in 70 to 80% decomposition of the pads during the next growing season. Dung pads exposed in other months had smaller insect biomasses and smothered the growth of new vegetation for at least two growing seasons; at the slowest degradation rate, individual dung pads still smothered 50% of the underlying potential forage-producing area during the fourth growing season. Insecticide-treated dung pads exposed in May required 3 to nearly 4 years to totally degrade, but approved insecticides could be fed to cattle grazed in dry rangeland pastures from about mid-June through September without adversely affecting natural degradation rates of cattle dung pads. Other factors assessed, evaluated, and reviewed were different types of bioassays for assessing dung pad degradation, factors affecting the process and rate of degradation, and the adverse economic impact associated with dung pad fouling, plus the rejection of associated rank growth of forage.