Intake in cattle of a ground switchgrass and alfalfa hay mixture blended with various levels of sucrose or citric acid

Palatability of feed affects voluntary intake. The objectives were to evaluate preference by bovine for sweet (sucrose) or sour (citric acid) blended with a mixture of ground switchgrass (42 g crude protein/kg dry matter) and alfalfa hay (176 g crude protein/kg dry matter). Flavors were dissolved in 50 mL deionized water per kg of hay for blending. In Experiment 1, sucrose hay (S100) had 100 g sucrose added per kg hay. Citric acid hay (CA50) had 50 g citric acid added per kg hay. Control hay (CON) had 50 mL deionized water added per kg hay. In Experiment 2, treatments were CON, sucrose added at 25 g per kg hay (S25), S100, 150 g per kg hay (S150). Citric acid added at 25 g per kg hay (CA25), and CA50. Hays were mixed in a horizontal mixer 3 d prior to each experimental period. Twelve beef cattle (initial BW = 283 ± 25 kg) were housed under a roof on expanded metal flooring with access to six feed locations designated I through VI, west to east. Cattle consumed 1 kg/day of supplement (corn, soybean hulls, and trace mineralized salt) that was fed daily, after hay orts were removed and weighed at 0800. Cattle were offered treatment hay equal to 6 g per kg BW at each feed slot and treatments were randomly assigned to two of the six locations at 0830. Cattle were given a 14-d adaptation to CON followed by a 7-d offer of treatments. In Experiment 1, cattle preferred S100 (3.42 ± 0.04 kg/d) over CON (2.8 ± 0.04 kg/d, P<0.01) and CA50 (0.32 ± 0.04 kg/d, P<0.01) and preferred CON over CA50 (P<0.01). In Experiment 2, cattle preferred CA10 over CON (P<0.02) and CA25 (P<0.02), and S100 was preferred over S150 (P<0.02) and S25 (P<0.02). Compared with control, cattle preferred hay flavored with sucrose up to 100 g per kg of hay, and preferred hay flavored with citric acid up to 10 g per kg of hay. Flavored feeds that are nutritionally adequate can be used to provide variety in the diet of cattle, where total intake increases when different feeds are presented together. Adding sugar may increase intake of undesirable feeds, or citric acid may be added at greater than 10 g per kg hay to limit intake of desirable feeds.