Jeff Heldt

Dr. Jeff Heldt

orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 April 2025 in Animals
Verified
Journal Article
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HLHuey Yi Loh
Huey Yi Loh
OGOctavio Guimaraes
Octavio Guimaraes
MTMeghan P. Thorndyke
Meghan P. Thorndyke
SJSam Jalali
Sam Jalali
JSJerry W. W. Spears
Jerry W. W. Spears
TETerry Engle
Terry 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.

22 October 2024 in Acta Agriculturae Scandinavica, Section A — Animal Science
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Journal Article
Open access
TRThiago Lauro Maia Ribeiro
Thiago Lauro Maia Ribeiro
BFBecca. B. Grimes Francis
Becca. B. Grimes Francis
CRCassidy. R. Ross
Cassidy. R. Ross
JDJustin. J. Delver
Justin. J. Delver
FFForest Francis
Forest Francis
Zachary SmithZachary Smith
Zachary Smith

1 January 2025 in Animal Bioscience
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Journal Article
Open access
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TRThiago Lauro Maia Ribeiro
Thiago Lauro Maia Ribeiro
BFBecca. B. Grimes Francis
Becca. B. Grimes Francis
EDErin R. DeHaan
Erin R. DeHaan
CRCassidy R. Ross
Cassidy R. Ross
JDJustin. J. Delver
Justin. J. Delver
Zachary SmithZachary Smith
Zachary 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.

2 October 2025 in Acta Agriculturae Scandinavica, Section A — Animal Science
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Journal Article
Open access
TRThiago Lauro Maia Ribeiro
Thiago Lauro Maia Ribeiro
JHJeff Heldt
Jeff Heldt
EWEmma H. Wall
Emma H. Wall
BWBlake K. Wilson
Blake K. Wilson
NONatally Owen
Natally Owen
Zachary SmithZachary Smith
Zachary Smith

6 March 2025 in Veterinary Sciences
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Journal Article
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GJGrace H. Jardon
Grace H. Jardon
MKMadison R. Kovarna
Madison R. Kovarna
JHJeff Heldt
Jeff Heldt
EWEmma Wall
Emma Wall
AMAna Clara Baiao Menezes
Ana Clara Baiao 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.

1 October 2004 in The Professional Animal Scientist
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Journal Article
Open access
DSD.W. Sanson
D.W. Sanson
SPS.I. Paisley
S.I. Paisley
RGR.J. Gaebe
R.J. Gaebe
DHD.H. Hixon
D.H. Hixon
JHJeff Heldt
Jeff Heldt
DMD. Moore
D. Moore