Effect of Phosphoric Acid Level in Liquid Supplement on Supplement Intake of Beef Heifers

Effects of lowering pH of sugarcane molasses-based liquid supplements on ad libitum supplement intake were evaluated in an 84-d trial. This experiment was conducted, at Gainesville and Ona locations, during Summer 2000. Four treatments were a 16% crude protein liquid supplement (pH 4.2), and the same supplement acidified to pH 3.4, 2.9, and 2.3 using feed grade phosphoric acid added at 3, 6, and 9%, respectively. Intakes of these supplements were compared using a 4 x 4 Latin square design with five crossbred beef heifers (600 to 850 lb initial BW) in each of four 3 or 4 acre bahiagrass pastures. Each treatment was offered ad libitum in 55 gal capacity tanks with one lick wheel. Each period of the Latin square was 3 wk long and liquid supplement consumption was measured weekly. Daily liquid supplement consumption at Gainesville averaged 5.68 lb (range 3.15 to 7.24 lb) and average daily consumption at Ona was 4.25 lb (range 1.85 to 6.31 lb). Across both locations, daily supplement consumption decreased 13% (P=0.08) for pH 3.4, 30% (P<0.01) for pH 2.9, and 64% (P<0.01) for pH 2.3 compared to control (6.78 lb). Lowering pH of liquid supplement was an effective method of reducing daily supplement consumption.