Growth Performance and Carcass Characteristics of Finishing Steers Given an Oral Dose and Daily Supplement of Yucca-derived Sarsaponin1

Three hundred sixty-eight crossbred yearling steers (BW = 334 ± 17 kg) were used in a 134-d experiment to compare fnishing diets based on dry-rolled corn, with (YUCCA) and without (control) yucca-derived sarsaponin. On d 0, cattle assigned to YUCCA were orally drenched with 50 mL of SarStart Plus (SarTec Corp., Anoka, MN), and control cattle were orally drenched with a equivalent amount of water. Steers receiving YUCCA were supplemented with 1 g/d per steer of a dried yucca extract (SarStart DSC) for the first 30 d on feed, and then with 0.5 g/d per steer from d 31 to harvest. Starting on d 20 and ending on d 61, weekly fecal samples were taken via rectal palpation from approximately one-third of the steers. A subsample consisting of 280 randomly selected samples was used to assess starch concentration in feces. Total fecal collections were used to estimate diet DM digestibilities for 18 of the 54 pens over a 96-h sampling period. Dry matter intake, ADG, G:F, fecal starch concentration, and apparent total-tract DM digestibility were not different (P > 0.15) for YUCCA and control. In addition, dress yield, carcass weight, USDA quality grade, USDA yield grade, and percentage of liver abscesses were also not different (P > 0.13). Oral drenching of SarStart Plus at processing and daily administration of SarStart DSC in the feed had no effect on growth performance, carcass characteristics, or DM digestibilities.