Evaluation of FerAppease Administered at Arrival and Time of Reimplant on Feedlot Performance and Carcass Characteristics of Yearling Beef Steers | UNL Beef

Authors: Casten L. Loseke, Graduate Student; Galen E. Erickson, Professor; Jessica L. Sperber, Assistant Professor, Animal Science, Lincoln.

Summary with Implications

Cattle experience stress in the feedlot during handling events such as initial processing and reimplant that can negatively impact morbidity and mortality, feedlot performance, and carcass outcomes. Application of a maternal Bovine Appeasing Substance (mBAS) marketed as FerAppease (FERA Diagnostics and Biologicals) has been hypothesized to mitigate stress in cattle. A commercial feedlot study compared the effectiveness of FerAppease applied in 10mL doses to yearling native beef steers at initial processing and reimplant to a placebo product on cattle performance, morbidity and mortality parameters, and carcass traits. Steers administered FerAppease tended to have improved feed conversion on a carcass-adjusted basis. FerAppease did not impact intake or average daily gain. Carcass traits, morbidity, and death loss were not impacted by application of FerAppease. These data suggest that FerAppease may be effective in improving feed conversion when applied at arrival and reimplant to yearling feedlot steers.

Introduction

Beef cattle encounter a multitude of stressors from birth to harvest which can negatively impact animal behavior and productive performance. Critical events contributing to elevated stress in cattle include weaning, transport, castration, initial processing, additional sorting, reimplant, and terminal shipment for harvest. FerAppease (FERA Diagnostics and Biologicals) is classified as a maternal Bovine Appeasing Substance (mBAS) and is designed to reduce cattle stress by imitating the dam-offspring bond. FerAppease has an observable calming effect on cattle for up to 14 days post application and is intended to reduce recovery time and stimulate intake and gain following necessary stressful procedures in feedlot production, such as receiving and reimplant. Research and adoption by cattle producers has primarily focused on FerAppease application on calves during weaning, prior to transport, and upon feedlot arrival at initial processing. Research involving yearling cattle classified as “low risk” is warranted, as modern Nebraska feedlot systems include large populations of cattle that enter a terminal feedlot as yearlings. The objective of this experiment was to evaluate how administration of FerAppease on arrival and reimplant impacts feedlot performance, carcass characteristics, cortisol concentration, and health parameters of yearling steers.

Procedure

A finishing study was conducted at a commercial feedlot in central Nebraska from September 2024 to April 2025 using crossbred yearling steers (n = 1754; Initial BW = 933, SD = 55 lb) averaging 167 DOF (ranging 144 to 217 DOF). Steers were sourced from Nebraska, South Dakota, Wyoming, and Virginia, and the experiment used a randomized generalized block design with steers blocked by source and arrival date. At feedlot arrival, steers were randomized by gate sorting into two pens (1 pen per treatment) for each replication and were weighed and processed within 24 h of feedlot arrival. On d 1 steers were vaccinated, dewormed, implanted with 100 mg TBA and 14 mg estradiol benzoate (Synovex Choice; Zoetis), and received one of two treatments: a 10 mL dose of FerAppease® (FERA) or a 10 mL dose of a mineral oil placebo (CON) with 10 replications per treatment (20 experimental pens). Both FERA and CON were applied as 5 mL behind the poll and 5 mL to the skin above the muzzle using a pour-on gun. FERA and CON groups were processed separately and between treatments the chute was washed to eliminate exposure of FerAppease to steers on the CON treatment. Feedlot personnel were blinded to treatment as the FERA and CON treatments were labeled as A and B, respectively, and the mineral oil placebo applied to the CON steers was similar in color but without any active ingredient. A random number generator was used to select a subset of 5 steers per pen for tail switch hair sampling on d 1 and d 14 for cortisol analysis. Steers were reimplanted approximately 78 d (ranging 66 to 118 d) after initial processing with 200 mg TBA and 28 mg estradiol benzoate (Synovex Plus; Zoetis), were revaccinated, and received a second dose of assigned treatment either FERA or CON at the same dosage rate as initial dose. Steers were adapted to the final finishing diet over 22-d and four adaptation diets. Alfalfa hay was stepped down in percent inclusion from 30, 24, 17, 11, to 4.5% (DM basis) and corn silage was stepped down in percent inclusion from 15, 12, 9, 6, to 3% (DM basis) and were replaced with high-moisture corn. All steers were fed a common finishing ration (Table 1) for approximately 144 d. The meal supplement was included at 2.5% of the diet (DM basis), and levels of dry-rolled corn, high-moisture corn, and modified distillers grains varied based on availability and price. All diets within replications were identical for both treatments so any diet changes would not impact one treatment or the other. Steers received lubabegron (Experior; Elanco Animal Health) fed at a rate of 3.2 g/ton DM for the final 49 d on feed. Dry matter intake (DMI) was calculated using total pounds of feed offered (DM basis) to each pen divided by number of head in each pen across days. Average daily gain (ADG) was calculated on a deads-in, deads-out, live, and carcass-adjusted basis. Deads-in ADG was calculated by subtracting pen initial BW from pen final BW divided by head days that steers were alive. Deads-out ADG was calculated by removing deads initial BW. Live performance was calculated using a 4% shrink and carcass-adjusted BW was calculated from hot carcass weight (HCW) with a common 64.5% dress. Steers were harvested at a commercial abattoir (Cargill, Schuyler, NE), and HCW, ribeye area (REA), and USDA Quality Grade (QG) and Yield Grade (YG) were provided from plant closeouts as each pen was sold and harvested as separate lots. Live performance, carcass traits, and cortisol data were analyzed using the MIXED procedure of SAS with pen as the experimental unit. Health data were analyzed as a binomial distribution using GLIMMIX. Significance was considered at α ≤ 0.05 and a tendency was considered at 0.05 < α ≤ 0.10.

Table 1. Diet fed to evaluate the effect of FerAppease® or placebo administration at feedlot entry and time of reimplant on yearling steers¹.
Ingredient, % of DM
Dry-Rolled Corn	12.3
High Moisture Corn	59.8
Corn Silage	3
Alfalfa	4.5
MDGS²	17.9
Supplement³	2.5
Micro Ingredients⁴	0.03
¹Finishing ration fed for final 144 (124-184) days with Lubabegron fed for 49 (36-60) days at 3.2 g/ton DM. ²Modified distillers grains plus solubles. ³Meal supplement. ⁴Micro ingredients contain feed additives, minerals, and vitamins to meet or exceed cattle requirements.

Results

Feedlot Performance

Initial BW averaged 932 and 933 lb for FERA and CON respectively (P = 0.73), and there was no difference in DMI for cattle administered FERA compared to CON (P = 0.84; Table 2). Removals for chronic illness were included in both deads-in and deads-out analysis. There was no difference between treatments for ADG on a live or carcass-adjusted basis for deads-out analysis (P ≥). Administration of FERA tended to improve deads-out feed conversion (P = 0.09). During the experiment, seven of the FERA cattle and ten of the CON cattle were counted as mortalities and initial BW for deads were included in deads-in analysis.There was no difference in ADG or feed conversion on a deads-in live basis (P ³ 0.20). Feed conversion tended to improve by approximately 4% for steers administered FERA compared to CON on a carcass-adjusted basis (P = 0.08). There was a numerical increase in ADG on a deads-in carcass-adjusted basis (P = 0.17) from 4.21 to 4.31 lb/d for CON and FERA, respectively.

Table 2. Effect of FerAppease® or placebo administration at feedlot entry and time of reimplant on feedlot performance of yearling steers fed for approximately 167 DOF¹.
	Treatments²
Item	CON	FERA	SEM	P-Value
Pens, n	10	10
Initial no. of steers	879	873
Initial BW³, lb	933	932	1.8	0.73
DMI, lb/d	27.8	27.8	0.15	0.84
Deads-out analysis⁴
Live performance⁵
Final BW, lb	1653	1659	9.0	0.64
ADG, lb	4.24	4.32	0.068	0.39
F:G	6.58	6.45		0.26
Carcass-adjusted performance⁶
Final BW, lb	1656	1666	6.4	0.26
ADG, lb	4.32	4.36	0.037	0.42
F:G	6.54	6.37		0.09
Deads-in analysis⁷
Live performance⁵
ADG, lb	4.14	4.27	0.078	0.28
F:G	6.76	6.54		0.20
Carcass-adjusted performance⁶
ADG, lb	4.21	4.31	0.049	0.17
F:G	6.71	6.45		0.08
¹Performance data from removals from trial at reimplant, are included. ²Treatments FERA (FerAppease®) and CON (Mineral Oil) were applied at 10mL/head upon initial processing (d0) and at reimplant (d66-118). ³Average deads-in initial BW across pens within treatment. ⁴Deads-out analysis was calculated by removing Initial BW from steers that died or were removed from pen total, and subtracting from pen total Final BW, and using head days for surviving animals. ⁵Live Performance was calculated by gross pen weight prior to terminal shipment using a 4% pencil shrink. ⁶Carcass adjusted performance was calculated using HCW and a common 64.5% dressing percentage. ⁷Deads-in analysis was calculated by subtracting initial BW from Final BW, and using head days for surviving animals plus head days that dead and removed animals were alive and on trial.

Carcass Characteristics

Dressing percent was similar for cattle administered FERA and CON (P = 0.50; Table 3) and REA was unaffected by treatment (P = 0.77). There was no difference in marbling score between the two treatments (P = 0.53) and greater than 50% of steers on experiment graded Upper 2/3 Choice or better. The USDA calculated YG was similar for FERA and CON (P = 0.56) with 45 and 43% of steers on FERA and CON, respectively, calculating YG 4 and 5. Steers administered FERA had a 7 lb numerical advantage in HCW over CON, although this increase was not significant (P = 0.26).

Table 3. Effect of FerAppease® or placebo administration at feedlot entry and time of reimplant on carcass characteristics of yearling steers fed for approximately 167 DOF¹.
	Treatments²
Item	CON	FERA	SEM	P-Value
Pens, n	10	10
Carcasses, n	871	866
HCW, lb	1068	1075	4.1	0.26
Dressing percentage³	64.7	64.8	0.16	0.50
Marbling score⁴	528	533	5.3	0.53
REA, in²	15.24	15.28	0.105	0.77
Calculated Yield Grade⁵	3.39	3.37	0.048	0.56
¹Carcass data from removals from trial at reimplant, are included. ²Treatments FERA (FerAppease®) and CON (Mineral Oil) were applied at 10mL/head upon initial processing (d0) and at reimplant (d66-118). ³Dressing Percentage = Pen total HCW ÷ Pen total live weight after a 4% shrink. ⁴Marbling score: 400 = Small00 500 = Modest00, 600 = Moderate00. ⁵USDA yield grade equation: 2.50 + (2.5* adjusted fat thickness, in) + (0.2 x % KPH) + (0.0038 * HCW, lb) – (0.32 * REA, in2); USDA (2016).

Cattle Health and Cortisol Levels

During the experiment, there were 8 deads or removals from FERA treatment and 15 deads or removals from CON (Table 4). There was no difference in the percentage of cattle requiring treatment for illness, or percent of cattle treated once that required a second treatment between FERA and CON (P ≥ 0.53). There was no difference (P = 0.47) in percent death loss between treatments with 0.9 % death loss for FERA vs. 1.2 % CON. There was no difference in hair cortisol concentrations from samples collected on d 1 and 14 between treatments and the magnitude of change in hair cortisol was not impacted by FerAppease administration (P ≥ 0.70).

Table 4. Effect of FerAppease® or placebo administration at feedlot entry and time of reimplant on cortisol concentration and health parameters of yearling steers fed for approximately 167 DOF
	Treatments¹
Item	CON	FERA	SEM	P-Value
Morbidity², %
1 treatment required³, %	6.4	5.9	0.77	0.69
2 treatments required4, %	17.4	22.7	6.57	0.53
Mortality, %	1.2	0.9	0.33	0.47
Removals⁵, n (%)	5 (0.6)	1 (0.1)
Hair cortisol⁶, pg/mg hair
Day 0	2.57	2.47	0.220	0.76
Day 14	2.33	2.48	0.263	0.7
Difference	-0.244	-0.034	0.3837	0.7
¹Treatments FERA (FerAppease®) and CON (Mineral Oil) were applied at 10mL/head upon initial processing (d0) and at reimplant (d66-118). ²Morbidity was determined by steers treated in the duration of the experiment. ³1 treatment % = steers treated once ÷ initial number of steers. ⁴2 treatment % = steers treated twice ÷ steers treated once. ⁵Removals include chronic steers not administered a second treatment of CON or FERA at reimplant. ⁶Hair samples were taken near the end of the tail switch near the skin on a subsample of five steers/pen at initial processing and 14 days later for cortisol analysis.

Conclusions

The administration of FerAppease did not impact DMI, tended to improve feed conversion by 4%, and resulted in a numerical increase of 7 lb in HCW compared to steers that did not receive FerAppease at arrival and reimplant. FerAppease administration had no impact on morbidity and mortality parameters and USDA Yield Grade and Quality Grade were unaffected by FerAppease administration. Applying FerAppease to low-risk yearling steers at initial processing and reimplant may improve feed conversion.

Acknowledgment

Funding provided by FERA Diagnostics & Biologicals (College Station, TX). Carcass data provided by Cargill (Schuyler, NE) following harvest dates of experiment cattle. Cattle hair cortisol analysis provided by Texas A&M University (College Station, TX).