Evaluation of Maternal Bovine Appeasing Substance Administration and Feed Access Time on Finishing Cattle Performance, Behavior, and Carcass Characteristics

Authors

• Carsten L. Loseke, University of Nebraska-LincolnFollow

First Advisor

Galen E. Erickson

Second Advisor

Jessica L. Sperber

Committee Members

Jim C. MacDonald, Keara O'Reilly

Date of this Version

5-2026

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Animal Science

Under the supervision of Professors Galen E. Erickson and Jessica L. Sperber

Lincoln, Nebraska, May 2026

Comments

Copyright 2026, Carsten L. Loseke. Used by permission

Abstract

Novel products and bunk management techniques may significantly influence economically relevant performance metrics of feedlot cattle. The objective of the first experiment was to evaluate maternal Bovine Appeasing Substance (mBAS) administration on performance, carcass, health, and cortisol outcomes of yearling steers. Steers (n = 1,754, initial BW = 423 kg, SD = 25 kg) were received and assigned to pens for treatment allocation. Steers received either 10 mL of the mBAS or a mineral oil placebo at initial processing and reimplant. Hair samples were collected from a subset (n = 4 steers/pen) on d 0 and d 14. There was no difference in DMI or ADG , while carcass-adjusted G:F tended to improve for mBAS on a deads-in basis. There was no difference in HCW, marbling score, or LM area, however, dressing percent tended to improve for mBAS. Administration of the mBAS did not impact quality or yield grade, mortality, or hair cortisol concentration. Application of mBAS at feedlot arrival and reimplant may modestly improve feed efficiency in yearling steers. The objective of the second experiment was to evaluate the effects of feed access time on performance, feeding behavior, ruminal pH and carcass outcomes in yearling heifers. Heifers (n = 234; initial BW = 447 kg, SD = 36 kg) were fed for 104 d in pens equipped with electronic feed bunks. Heifers were given either 12, 15, 18, 21, or 24 h of feed access and a subset received pH boluses. Carcass adjusted final BW, ADG, or G:F did not differ. As feed access time increased, DMI increased linearly. The DMI of 24 h heifers was greater than 12 h, but not different compared to 18 or 21 h treatments. The variation (CV) of DMI and liver abscess incidence increased linearly as feed access time increased. As feed access time increased from 12 h to 24 h, eating duration increased linearly and eating rate decreased linearly and the intra-day ruminal pH change decreased linearly. Feed access time greater than or equal to 15 h did not negatively impact DMI, ADG or HCW.

Advisors: Galen E. Erickson and Jessica L. Sperber