PS8-16. Effects of Feeding Varying Levels of a Glucogenic Precursor Blend on Performance Health and Metabolic Status of High-risk Heifers at Receiving.

Abstract The objectives of this study were to determine the effects of a blend of glucogenic precursors (Enercore, Biosen LLC.) in a total-mixed receiving ration on performance and morbidity outcomes. Total mixed rations were formulated to provide encapsulated Enercore in a premix to achieve 0, 1.98, 3.97, and 5.95 g of Enercore/kg of finished feed to provide average doses of 0 (Control), 20 (E20), 40 (E40), and 60 (E60) g/calf per day, respectively, for a 70-day receiving study from September 12 to November 21, 2025. Heifers (n = 176; initial BW = 267.6 ± 39.33 kg) were sourced from Beaver County Stockyards in Beaver, OK, and arrived at the Willard Sparks Beef Research Center in Stillwater, OK two days prior to the start of the study. Upon arrival, heifers were weighed, administered a mass treatment of tulathromycin (Arovyn; Merck Animal Health USA, Rahway, NJ), and provided hay and water. Heifers were stratified and sorted by BW, and were randomly assigned to pens, with pens being blocked in groups of 4 adjacent pens. Unshrunk weights were collected before the morning feeding on d 1 every 14 days through day 70. Fecal grab samples were collected every 14 days to evaluate fecal score and starch analysis. Feed samples were collected every 14 days. Feed and fecal grab samples were composited within pen and analyzed for nutrient composition and starch content by ServiTech (Dodge City, KS). Plasma samples were collected on days 42 and 69, and were analyzed for glucose and lactate concentrations (mg/dL). Average Enercore dose was 0, 21.7, 42.4, and 60.9 g/day, respectively and daily DM intake decreased linearly (P < 0.05) with increasing Enercore dose. There was a cubic (P = 0.04) response on heifer BW on day 28 and ADG from d 1- 28) with Enercore 20 having greater (P = 0.05) BW and ADG than Control on d-28 and tending (P = 0.10) to have greater BW and ADG than Control on day 70. Feed efficiency was affected by Enercore dose with a cubic response (P = 0.04) on day 28 and tendencies (P ≤ 0.10) for cubic responses on days 42, 56, and 70. Glucose and fecal starch concentrations increased at the end of the experiment (P < 0.001), no treatment differences were observed (P = 0.7793). There was a quadratic effect (P = 0.03) of Enercore dose on days to first BRD treatment with no other health effects observed. Feeding Enercore resulted in a cubic response (P = 0.04) for net returns on day 28 with Enercore20 having $46/heifer greater net returns than Controls. This proprietary blend of glucogenic precursors appears to be a promising tool to increase feed efficiency and net returns of heifers during receiving.