JHJeff S. Heldt

Jeff S. Heldt

*This is an algorithmically generated author record based on publicly available information.

Jeff S. Heldt has a total of 28 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Effects of a formulated botanical blend on growth performance and carcass characteristics in feedlot cattle: a pooled analysis

    by Thiago Lauro Maia Ribeiro, Jeff S. Heldt, Emma H. Wall, Blake K. Wilson, Natally Owen, Shane Davis, Warren C. Rusche, Federico Podversich, Zachary K. Smith


  • Open Access

    Trace Mineral Source Impacts Volatile Fatty Acid Profile and Rumen Trace Mineral Solubility in Feedlot Steers

    by Huey Yi Loh, Octavio Guimaraes, Meghan P. Thorndyke, Sam Jalali, Jerry W. Spears, Jeff S. Heldt, Terry E. Engle

    Two experiments were conducted to evaluate the effects of trace mineral (TM) source on: (1) nutrient digestibility and rumen fermentation characteristics, (2) rumen TM solubility, and (3) TM binding strength on ruminal digesta. In experiment 1, twelve cannulated Angus steers were adapted to a high-concentrate diet, blocked by body weight, and randomly assigned to dietary treatments consisting of 18, 40, or 90 mg of supplemental Cu, Mn, and Zn/kg DM, respectively, from either sulfate (STM) or hydroxy (HTM) sources. Following diet adaptation, total fecal and rumen fluid were collected over a 5 d period. Nutrient digestibility was not affected (p > 0.15) by TM source. Steers supplemented with HTM had greater (p < 0.05) ruminal molar proportions of propionate and lower (p < 0.05) molar proportions of butyrate compared to STM-supplemented steers. In experiment 2, steers received a single pulse dose of their respective TM treatments via the cannula. Ruminal samples were obtained at 2 h intervals from −4 to 24 h post-dosing. Ruminal-soluble Cu concentrations were greater (p < 0.05) for STM-dosed steers. Steers receiving HTM had greater (p < 0.01) Cu and Zn and lower (p < 0.01) Mn released from digesta compared to those receiving STM.


  • Open Access

    Effects of Botanical Blend of Turmeric, Capsicum, and Pepper Extracts on Colostrum and Milk Yield and Quality, Passive Transfer of Immunity, and Performance of Beef Cow–Calf Pairs

    by Grace H. Jardon, Madison R. Kovarna, Jeff S. Heldt, Emma H. Wall, Ana Clara B. Menezes

    This study evaluated the effects of a botanical supplement (a formulated proprietary blend of turmeric, capsicum, and black pepper oleoresin in a fat carrier; PHYT), fed pre- and post-calving, on colostrum and milk yield and the quality, passive transfer of immunity, and performance of cow–calf pairs. Twenty-three (BW = 532 ± 9.13 kg; age 36 mo) crossbred Angus cows were randomly assigned to three treatment groups: (1) not supplemented (CON, n = 7); (2) supplemented with 250 mg/head/day (PHYT250, n = 8); or (3) supplemented with 500 mg/head/day (PHYT500, n = 8) of the botanical supplement. The cows were individually fed the supplement from 30 days (±6 days) pre-calving to 60 days post-calving. Colostrum was collected on d 0 (pre-suckling), and d 1, d 2, and d 3 post-calving. The total milk from all quarters was collected 45 and 90 d post-calving and at weaning. Colostrum and milk volumes were recorded, and samples were analyzed for percentages of fat, protein, milk urea nitrogen, other solids, and lactose. Colostrum samples were analyzed for concentrations of IgG, IgA, and IgM, and milk samples were analyzed for IgG concentration using radial immunodiffusion. Blood samples were collected from dams and calves, and serum was analyzed for concentrations of IgG (cows and calves) and IgA (calves). Cow and calf BW were measured periodically until weaning. Supplementation with PHYT linearly increased fat in colostrum (CON = 3.29, PHIT250 = 4.23, and PHYT500 = 4.17 ± 0.77%; p = 0.05) and IgA in calf serum (96.91, 151.69, and 183.42 ± 29.78 mg/dL for CON, PHYT250, and PHYT500, respectively; p = 0.04) and tended to linearly increase concentrations of fat in milk (CON = 3.84, PHYT250 = 4.05, and PHYT500 = 4.71 ± 1.04%; p = 0.07), IgG in calf serum (2082.31; 2196.29; and 2577.78 ± 213.08 mg/dL for CON, PHYT250, and PHYT500, respectively; p = 0.09), and IgM in colostrum (CON = 179.04; PHYT250 = 170.79; PHYT500 = 218.30 ± 16.08 mg/dL; p = 0.09). A quadratic response was observed for calf ADG (p = 0.03), where CON (0.99 ± 0.03 kg/d) was less than PHYT250 (1.10 ± 0.03 kg/d), and intermediate values were observed for PHYT500 (1.01 ± 0.03 kg/d). In summary, supplementation with PHYT led to a linear increase in colostrum fat and IgA levels in calf serum. Additionally, supplementation tended to linearly elevate fat concentrations in milk, IgG levels in calf serum, and IgM levels in colostrum. Our results suggest that supplementing beef cows in late gestation and early lactation with 250 or 500 mg/head/d of PHYT improves colostrum quality and calf health and performance. Further investigation is needed to determine both the biological significance and the economic benefits of botanical additives in beef production.


  • Open Access

    Influence of long-term supplementation of a formulated botanical blend on growth performance and carcass traits in feedlot steers

    by Thiago Lauro Maia Ribeiro, Becca. B. Grimes Francis, Erin R. DeHaan, Cassidy R. Ross, Justin. J. Delver, Forest L. Francis, Jeff S. Heldt, Emma H. Wall, Warren C. Rusche, Zachary K. Smith

    Objective: The objective of this study was to determine if a formulated blend of capsicum oleoresin, clove essential oil, and garlic essential oil (Fytera Advance - Selko USA, Indianapolis IN, USA; CCG) influences measures of cattle growth, efficiency, or carcass traits, during the finishing phase in steers fed a concentrate-based diet.Methods: Charolais×Angus steers (n = 96; initial shrunk body weight [BW] = 391±34.0 kg) were used in a 144-d (16 February 2023 to 9 July 2023) finishing feedlot experiment in Brookings, SD, USA. Steers were individually weighed and allotted to one of 14 pens (6 to 7 steers; 7 pens/treatment) in a randomized complete block design and randomly assigned to 1 of 2 treatments: control diet without the test product (CON) or a diet including CCG at 500 mg/steer daily (CCG). Steers were fed twice daily, and bunks were managed according to a slick bunk system.Results: There were no differences (p≥0.10) in any growth performance outcomes from d 1 to 35, 36 to 70, or 71 to 98. From d 99 to 144 steers from CCG tended to have 5% greater average daily gain (p = 0.09) and 8% improved feed conversion (G:F) (p = 0.01). No differences (p≥0.15) were noted for cumulative growth performance measures. No differences were noted for any carcass measurements or categorical carcass outcomes, nor lung or liver health outcomes (p≥0.15).Conclusion: The use of CCG had no influence on cumulative growth performance responses. However, the use of CCG improved G:F during the late feeding period.


  • Open Access

    Evaluation of a phytogenic blend fed with monensin on post-weaning growth performance, health, and sera metabolite responses during the initial 56 d feedlot receiving period in steer calves

    by Thiago Lauro Maia Ribeiro, Becca. B. Grimes Francis, Cassidy. R. Ross, Justin. J. Delver, Forest L. Francis, Jeff S. Heldt, Emma H. Wall, Warren C. Rusche, Zachary K. Smith