Selective Grazing Induced by Animal Excreta I. Evidence of Occurrence and Superficial Remedy

Abstract

Recurring grazing patterns by dairy heifers and steers under rotational grazing of brome and alfalfa-brome were measured by mapping within staked areas over a 2-year period. An average of 81% of all dung deposited by the animals 3 to 4 wk before grazing caused complete refusal of the forage in the area. Complete refusal of dung-affected forage was reduced to 68% after 2 to 3 months. Dung deposited on brome caused a greater refusal of forage than deposited on alfalfa-brome. Of all areas not grazed, 93% contained dung spots from periods prior to measurement, while only 1% of completely consumed forage areas contained dung. The effect of sprayed sugar or molasses on consumption of dung-affected brome was measured in 1961. Both sweetening agents resulted in consumption of grass over dung spots, while untreated controls remained ungrazed. Molasses was more effective than sugar in completely overcoming rejection of dung-affected forage.