The effects of SarStart DSC on performance and carcass characteristics of finishing beef steers

One hundred twenty Angus, Red Angus. Angus-Hereford, and Red Angus-Hereford steers with an initial body weight (BW) of 366 kg were fed for 112 to 138 d to determine the effects of feeding SarStart DSC, a sarsaponin extracted fiom Yucca shidigera. in either a dry-rolled (DR) corn-based diet or a steam-flaked (SF) corn-based diet versus a dry-rolled corn-based diet and a steam-flaked corn-based diet without SarStart DSC. The four diets were balanced to contain equal energy and crude protein (CP). Steers were blocked by BW into a light block and a heavy block and assigned randomly to one of the four treatments. Five steers were placed in each pen with six pens per treatment. Steers were fed once daily and weighed every 28 d during the trial. Performance records, including average daily gain (ADG), dry matter intake (DMI), and feed:gain ratio, were recorded for each 28-d period. Heavy block steers were shipped to a commercial slaughter facility after 112 d on feed, and Light block steers were shipped to a commercial slaughter facility after 138 d on feed. Carcass data were collected and recorded. A second experiment involved measurement of in vitro dry matter disappearance (IVDMD). Fresh ruminal fluid was collected and mixed with an artificial saliva buffer. The ruminal fluid-buffer mixture was incubated with four treatments, including dry-rolled or steam-flaked com with SarStart DSC and dry-rolled or steamflaked corn without SarStart DSC. Test tubes containing the four treatments and ruminal fluid plus buffer were incubated for 4, 8, 12, 16, 24, and 48 h. After incubation, samples were centrifiiged, and the residue was combined with an acidified pepsin solution and incubated for 48 h. Samples were then filtered and dried to determine IVDMD. A third experiment involved measurement of in vitro ammonia release. Fresh ruminal fluid was collected and mixed with an artificial saliva buffer. The ruminal fluid-buffer mixture was combined with the same four treatments used in the IVDMD experiment. Three flasks per treatment containing the mixture were oscillated for 8 h, and a 2-mL sample was taken from each flask at .5, 1,2, 4, and 8 h after initial inoculation. Samples were filtered and analyzed for ammonia concentration using a spectrophotometric procedure.