Benchmarking the United States bison meat industry: stakeholder perceptions, production parameters, and live animal factors affecting meat quality

Abstract

The objectives of this study were 1) to understand stakeholder perceptions regarding the bison industry, 2) to benchmark live animal characteristics and production parameters of the bison industry, and 3) to identify live animal factors related to animal welfare and their effect on specific quality characteristics of bison meat. A survey was conducted both online and in-person at the National Bison Association Winter Conference (2022). Descriptive statistics were performed on a total of 110 surveys. Most stakeholders (94%, n = 104) agreed that the industry should continue to grow, and the majority (99%, 108) agreed that animal welfare impacts meat quality. Facility design (80%, n = 88), animal handling (78%, 86), employee training (56%, 62), and transportation duration (56%, 62) were selected as the factors that affect animal welfare. More than half of the stakeholders selected flavor (67%, n = 74) as the most important quality attribute of bison meat. For the in-plant antemortem and postmortem parameters data was collected from three plants in the United States over the course of a year. A total of 2,284 bison (bulls: n = 1,101; cows: n = 199; heifers: n = 984) were included in the study. Antemortem measurements such as distance traveled, vocalization, prod use, mobility, and head bumps were measured, followed by postmortem measurements that included bruise score, live weight, dressing percentage, ribeye area, and instrumental color. Approximately 97% of bison (n = 2,213) had at least one bruise. The average distance traveled from producer to slaughter plant was (mean ± SD; 823 ± 583 km) and the average dressing percentage was (mean ± SD; 60.5 ± 3.3%). Average (mean ± SD) fat thickness and ribeye area were 1.4 ± 1.1 cm and 62.6 ± 9.8 cm², respectively. Approximately 30% (n = 676) of the bison in this study head bumped between 1 and 5 times in the restraining chute or the single-file gate before being stunned. Linear regression indicated that differences in lean a* were associated with plant, number of head bumps in the chute, ribeye area, fat thickness, live weight, and sex class (P < 0.05). Logistic regression indicated that season, sex class, live weight, plant, and season were associated with differences (P < 0.05) in bruising. These results can be used as a baseline for current production parameters and serve as the foundation for future research to monitor improvement.

Lay Summary

This project evaluated bison industry stakeholder perceptions on management, animal welfare, and meat quality with in-person and online surveys. Additionally, multiple live animal factors were measured to benchmark their influence on specific meat quality attributes. From the stakeholder surveys, animal handling, bison behavior, employee training, facility design, and transportation duration were identified as the most critical factors that could impact animal welfare in the bison production system. Moreover, the stakeholders understood that animal welfare is a critical component for bison production and that it directly affects meat quality. Live animal production parameters such as distance traveled, season, number of head bumps in the chute, sex class, and live weight were associated with differences in fat thickness, ribeye area, blood splash presence, and instrumental color of bison meat. The results from this study can be used as a baseline for industry improvements and future research.

Animal welfare, bison, meat quality, transportation

Introduction

The United States bison industry is growing both in size and popularity, with bison slaughter numbers increasing steadily over the past several years (USDA, 2022a, 2023a; 2024a). According to the United States Department of Agriculture (USDA) National Monthly Bison Report (USDA, 2023a), a total of 68,939 bison were harvested in the United States from February 17 to December 15, 2023. In comparison, the number of bison slaughtered during the corresponding period in the years 2022 and 2021 were 65,927 and 59,614, respectively (USDA, 2024a). There are nine federally inspected bison slaughter facilities, which are distributed across seven states within the country (USDA, 2023b). Media articles indicate that consumers perceive bison meat products as a healthy sustainable protein (Sims, 2016; Gazdziak, 2018; Madhivi, 2020) compared to other livestock and poultry meat. Additionally, bison meat is often considered a healthy lean protein as it typically contains less fat and cholesterol compared to beef (USDA, 2022b). A recent study with human subjects examining the effect of consuming bison meat compared to beef by analyzing blood lipids, oxidative stress markers, and endothelial function for 7 wk indicated that the consumption of bison results in reduced inflammation, lower oxidative stress, and lower atherogenic risk compared to beef consumption (McDaniel et al., 2013). The lower cholesterol and fat content inherent in bison meat may be the primary factors contributing to its recognition and value among consumers. Therefore, the nutritional composition of bison meat is a healthy alternative in the market, attracting health-conscious consumers.

There are some distinct behavioral differences between bison and domestic cattle (Rioja-Lang et al., 2019). Therefore, the facility design, transportation logistics, and animal handling of bison tend to be modified from beef cattle to accommodate differences in bison behavior. During the initial stages of bison production, the animals spend most of their time grazing in pastures, after which bison are usually transported directly to the slaughter plant or to a feedlot for finishing (Tielkes and Altman, 2021). Transporting bison can result in injuries during the process, and this can affect trim loss (McCorkell et al., 2013). Studies have shown that blood cortisol levels (an indicator of stress) were greater in bison that had been transported versus bison that were slaughtered on-farm (Galbraith, 2011). Additionally, bison have horns that can cause bruising during transportation and handling, leading to trim loss during fabrication (McCorkell et al., 2013).

Although both cattle and bison are ruminants, their meat quality attributes differ. Bison meat is darker than beef due to differences in muscle fiber types and a greater myoglobin concentration in bison (Galbraith et al., 2014). Moreover, bison meat color is unstable compared to beef and browns relatively quickly during retail display in oxygen-permeable packaging (Sood et al., 2020). Unlike beef, bison longissimus lumborum muscles contain minimal marbling (Ding et al., 2016) and are darker (Galbraith et al., 2014), which impedes the direct application of the USDA grading system that exists for beef to bison. Another factor that could potentially affect bison meat grading is diet (Marchello and Driskell, 2001). Previous studies have indicated that corn-based diets could potentially generate bison with higher marbling compared to grass-fed (Janssen et al., 2021). Moreover, there is currently limited research on bison producer perspectives regarding quality grading application to their products.

The beef industry has been able to continuously improve quality using the National Cattlemen’s Beef Association (NCBA) National Beef Quality Audit (NBQA) data which has been conducted since the early 1990s. The NBQA benchmarks meat quality and welfare attributes of cattle arriving at slaughter plants approximately every 5 yr and serves as a baseline for the beef industry in the United States. The beef industry has made significant improvements in animal welfare and meat quality attributes utilizing the NBQA information (e.g., reduction of injection site lesions, and awareness of carcass bruising). However, similar benchmarking does not exist for the bison industry, and to the authors’ knowledge there is no data on stakeholder perceptions related to bison meat production and carcass quality outcomes at slaughter that impact carcass value. As the bison industry continues to grow, benchmarking will be instrumental in establishing guideposts, identifying needs to drive quality enhancements, and to ultimately drive improvement and profitability throughout the supply chain. Therefore, the objectives of this study were 1) to understand the perceptions of individuals who work in the bison industry regarding animal welfare, management, and meat quality, 2) to benchmark live animal and carcass characteristics of bison, and 3) to determine specific antemortem factors that impact quality characteristics of bison meat.

Materials and Methods

Survey population and recruitment

The survey was approved by Colorado State University’s (CSU’s) Institutional Review Board prior to study initiation (IRB Approval #2871). The target population for this survey consisted of cow–calf producers, finishers, processors, distributors, and other individuals who work in the bison industry. The survey was distributed during the National Bison Association (NBA) Winter Conference in Denver, CO, on January 20, 2022. Researchers hosted a booth at the conference and asked attendees (total conference attendees n = 245) if they were interested in filling out a survey. Attendees could take the survey on an iPad (7th Generation, Apple Inc., Cupertino, CA) or on a personal device. Additionally, all conference attendees received a flyer with conference registration materials which included a quick response code to take the survey. Respondents were not offered any incentive for participation. Participation was voluntary, and respondents could skip questions or stop the survey at any time. The only required question was the initial question confirming consent to participate. One week after the conference ended, an email was shared with approximately 1,300 members of the NBA inviting them to participate in the survey.

Survey format

The survey was created in Qualtrics (Qualtrics, WA, USA) and developed by an interdisciplinary team with proficiency in animal welfare and meat science. The survey was tested before distribution to ensure functionality and clarity. The survey had a total of 22 questions including Likert, open-ended, and multiple-answer questions (Supplementary Material). The survey included questions about the current bison industry growth, animal welfare, marketing, and bison meat quality. Demographic questions included age, gender, race, time working in the industry, size of operation, location of operation, and sector of the industry they worked. The survey was designed to take <30 min to complete. Many questions had a text option to write a personalized answer if none of the options given represented the respondent’s point of view.

Live Animal Data Collection

This study was observational; therefore, an IACUC waiver was granted (IACUC #: 2672). This study was conducted from November 2021 to December 2022. A CSU research team visited three bison processing plants in the Western United States. These plants harvested approximately 50 to 180 bison per day.

Antemortem information

The slaughter date, lot number, lot headcount, and producer were collected by a CSU student at the live animal holding pens. The estimated distance traveled to the slaughter facility was calculated using the shortest distance estimated by GoogleMaps (Google, CA, USA) using the producer or feeder location to the slaughter facility (distance in kilometers). The season was recorded based on the following date cutoffs: Spring—March 1st to May 31st; Summer—June 1st to August 31st; Fall—September 1st to November 30th; Winter—December 1st to February 29th in a leap year. Producer information and sex classes were provided by the processing facilities. Sex classes were bulls, cows, and heifers.

A trained graduate student with past experience evaluating animal handling and movement scored mobility, electric prod use, and vocalization when animals moved from the holding pens to the restraining chute (i.e., restrainer or knock box). Mobility was tallied for the following categories: dead/downers (i.e., not mobile), normal moving animals (i.e., moved without any problems), and abnormal (i.e., limping or refusing to move). Electric prod use was tallied for a number of animals prodded (not for a number of times prodded) and the number of animals that grunted (yes/no) was also recorded at this time.

Animal live weights were collected either in the restraining chute (built-in scale) or immediately after stunning the animal (prior to exsanguination). At the restraining chute, grunt score (yes/no) and number of head bumps in the chute were recorded. Visual mud coverage was scored either before the bison entered the restraining chute or after the bison was stunned and hung (this was plant-dependent). The number of head bumps in the chute was defined as when the animal intentionally and forcefully hit the inner surface of the chute. If the plant did not have a restraining chute where bison could head bump, head bumps were recorded in a single file prior to the final restrainer. Visual mud coverage was assessed with an ordinal scale from 1 to 3 (1 = less than 1/3 mud coverage, 2 = between 1/3 and 2/3 mud coverage, 3 = more than 2/3 mud coverage). A specific carcass ID was assigned at the processing facility (added postharvest) and was used to trace each individual carcass through the slaughter facility. Hot carcass weights were collected after the bison were fully processed (skinned, eviscerated, and trimmed). Cold carcass weights were taken before the carcasses were cut into primals after chilling for approximately 18 to 23 h.

Postmortem Data Collection

Bruising score

A carcass map, adapted from Strappini et al. (2012), was used to determine bruise location of each individual carcass (Figure 1). The specific modification was the addition of two sections representing the front legs of the animal (R8 and L8). Bruising was marked on the carcass map where the bruise was observed. Additionally, the length of the longest part of the bruise was used to estimate bruise size using a 0 to 4 visual scoring system: 0 = no bruise; 1 = greatest length between 0.1 and 7.62 cm, 2 = between 7.63 and 15.24 cm; 3 = between 15.25 and 30.48 cm, and 4 = greater than 40.48 cm. Multiple bruises within a section were recorded; however, only the largest bruise for each specific section was considered in this study.

Figure 1.

Carcass bruising map used in the current study adapted from Strappini et al. 2012.

Meat quality measurements

The following measurements were taken approximately 12 h postmortem in the carcass coolers. The carcasses were ribbed between the 12th and 13th ribs and allowed to bloom in the coolers for 1 h. The right side of the carcass was used to get the following measurements: instrumental color, ribeye area, backfat thickness, and blood splash presence. If the right side of the carcass was too damaged to analyze or if the ribbing was not done properly, measurements were taken on the left side of the hanging carcass. Instrumental color was collected using a HunterLab MiniScan XE Plus spectrophotometer (illuminant A and 10° standard observer; HunterLab, VA, USA) presenting values according to the CIELAB color space (L*a*b*). An average of 3 readings was used, and these measurements were taken across the longissimus thoracic area avoiding large intramuscular fat. The colorimeter was calibrated before the start of every session and its aperture was cleaned between all carcasses to avoid the accumulation of fluids or fat. The ribeye area was calculated using a transparent grid (loin eye area grid) with squares of specific known area. Trained researchers placed the grids over the ribeye and counted the squares to calculate the ribeye area (cm²) of the longissimus thoracic muscle. Fat thickness was evaluated on the face between the 12^th and the 13^th ribs, two-thirds of the length of the ribeye from the medial plane to the lateral plane, and the measurement was taken from the sagittal plane towards the medial plane using a stainless-steel ruler. The presence of blood splash was recorded (yes or no); blood splash was present if the longissimus thoracic muscle had the presence of ecchymosis.

Statistical analysis

The survey data were exported from Qualtrics (Qualtrics) to Microsoft Excel (Microsoft, WA, USA). Descriptive statistical analysis was performed using JMP (Statistical Discovery, NC, USA) software. Live animal and postmortem data were exported from Microsoft Excel (Microsoft) to JMP (Statistical Discovery). Descriptive statistics, linear regression, and logistic regression were performed. Linear regression was used for dressing percentage, ribeye area, fat thickness, and instrumental color. Logistic regression was done for bruising and blood splash. Model selection was done by stepwise backward elimination based on parameter significance (P < 0.05) keeping only significant parameters in the models. Factors considered for dressing percentage were number of head bumps in the chute, ribeye area, fat thickness, distance traveled, sex class, mud score, bruise score (bruised or not), season, plant, live weight, and grunt score (yes/no). Factors considered for ribeye area were fat thickness, distance traveled, sex class, mud score, bruise score, season, plant, live weight, and grunt score. Factors considered for fat thickness were ribeye area, distance traveled, sex class, mud score, bruise score, season, plant, live weight, and grunt score. Factors considered for instrumental color were a number of head bumps in the chute, ribeye area, distance traveled, fat thickness, sex class, mud score, bruise score, season, plant, live weight, and grunt score. Lot was included as a random effect in all linear regression models. Factors considered for bruising regression were number of head bumps in the chute, ribeye area, fat thickness, distance traveled, sex class, mud score, season, blood splash, and live weight. Factors considered for blood splash regression were number of head bumps in the chute, ribeye area, fat thickness, distance traveled, sex class, mud score, bruise score, season, and live weight. For logistic regression models, lot was not included due to confounding with other variables. Heat maps for bruising by sex class were created in a binary manner (bruise present in a carcass section: yes or no), counting the total percent not bruised and the percent bruised (regardless of size) for a specific carcass section and values were presented in percentages. The dressing percentage was calculated by dividing the hot carcass weight by the live weight and expressing the result as a percentage.

Results

Survey

Seventy individuals (out of 245 attendees) completed surveys at the NBA conference, and 52 individuals (out of 1,300 members) completed the survey online after the conference, resulting in a total of 122 responses. Ten respondents completed less than 10% of all questions, and two individuals were not involved in the industry, so these were removed from the final analysis. A total of 110 surveys were included in the analysis.

Demographics

Respondent demographics are reported in Table 1. Seventy-three percent (n = 80) of the respondents were men, and 24% (n = 27) were women. The majority of respondents (87%, n = 93) identified as White. Sixty percent (n = 66) of the respondents had been working in the bison industry for more than 10 yr. The survey was answered by cow–calf producers (n = 76), finishers (n = 42), retailers (n = 29), processors (n = 13), and others (n = 28; many of the respondents were involved in more than one type of operation). In a question that allowed for multiple answers, many respondents indicated that their businesses were in the Midwest and West regions of the United States (40.9%, n = 45, and 36.6%, n = 40, respectively). Fewer respondents worked in the Southwest (10.9%, n = 12), Southeast (5.4%, n = 6), Northeast (4.5%, n = 5), and Alaska and Hawaii (1.8%, n = 2).

Table 1.

Summary of respondent demographics (n = 110)

Description	Percent (n)
Time in the industry
<1 yr	2 (3)
1 to 5 yr	19 (21)
6 to 10 yr	16 (18)
>10 yr	60 (66)
Gender
Men	73 (80)
Women	24 (27)
Prefer not to answer	1 (2)
Industry location1
Alaska or Hawaii	1 (2)
Midwest	40 (45)
Northeast	4 (5)
West	36 (40)
Southeast	5 (6)
Southwest	10 (12)
Industry sector2
Cow–calf producer	69 (76)
Finisher	38 (42)
Processor	12 (13)
Retailer	26 (29)
Other	25 (28)
Race
Hispanic or Latino	<1 (1)
Native American	2 (3)
Prefer not to answer	8 (9)
White	87 (93)
Average age	53

¹Midwest (IA, IL, IN, KS, MI, MN, MS, ND, NE, OH, SD, and WI), Northeast (CT, DE, MA, ME, MD, NH, NJ, NY, PA, VT, and RI), Southeast (AL, AR, FL, GA, LA, KY, MS, NC, SC, TN, VA, and WV), Southwest (AZ, NM, OK, and TX), and West (CA, CO, ID, MT, NV, OR, UT, WA, and WY).

²Most of the respondents were affiliated with more than one sector of the industry, therefore, many individuals selected more than one sector.

Industry growth and improvement

About 73% (n = 81) and 21% (n = 23) of the individuals strongly agreed and agreed, respectively, that the bison industry should continue to expand and grow. Individuals were asked a question that allowed for multiple answers about which attributes of the bison industry would benefit from improvements. Most selected responses (Figure 2) from a provided list of options were marketing (64%, n = 70), animal health (46%, n = 51), animal welfare (38%, n = 42) and production cost (38%, n = 42).

Figure 2.

Percent selected responses regarding attributes of bison that would benefit from enhancements or improvements (n = 110). Multiple answers allowed.

Animal welfare

Approximately 96% (n = 106) of the individuals agreed or strongly agreed that animal welfare is a critical component of bison production (Table 2). Almost all respondents (99%, n = 108) indicated they believe that animal welfare impacts meat quality. Over half  of the individuals strongly agreed (32%, n = 36) or agreed (28%, n = 31) that transportation to the slaughter plant is an area of concern due to its potential impacts on animal welfare. In a question that allowed for multiple answers, individuals were asked to select the factors that affect animal welfare within the bison industry from a provided list of options. Most selected responses were facility design (80%, n = 88), animal handling (78%, n = 86), employee training (56%, n = 62), and transportation duration (56%, n = 62; Figure 3).

Table 2.

Likert scale summary of responses regarding respondent perceptions of bison welfare during production and harvest (n = 110).

Statement	Strongly agree, % (n)	Agree, % (n)	Neither agree nor disagree, % (n)	Disagree, % (n)	Strongly disagree, % (n)	Do not know, % (n)	No response, % (n)
Animal welfare is a critical component of the bison production system	77 (85)	19 (21)	2 (3)	0.9 (1)	0 (0)	0 (0)	0 (0)
Animal welfare impacts bison meat quality	69 (76)	29 (32)	0 (0)	0.9 (1)	0 (0)	0 (0)	0.9 (1)
Transportation of bison to the slaughter plant is an area of concern due to its impacts on animal welfare	32 (36)	28 (31)	21 (24)	9(10)	1 (2)	6 (7)	0 (0)

Figure 3.

Percentage of selected responses collected from respondents concerning factors that impact animal welfare within the bison industry (n = 110). Multiple answers were allowed.

Meat quality

Sixty-seven percent (n = 74) of the individuals stated that the most important quality attribute of bison meat is flavor while other answers (color, health/nutrition, juiciness, quality, tenderness, and other) were selected by less than 11% (n = 12) of respondents. When asked if there were quality differences between grain- and grass-fed bison, 41% (n = 46) and 37% (n = 41) of the individuals strongly agreed and agreed with the statement, respectively (Table 3). When asked if grass-finished bison should be marketed as a premium product, 25% (n = 28) of the individuals strongly agreed, and 25% (n = 28) agreed. In a question about attributes of bison that provide added benefit/value to consumers that allowed for multiple answer selection from a provided list of options, the most selected options were healthy (84.54%, n = 93), lean meat (73.63%, n = 81), meat quality (70%, n = 77), and unique flavor (54.54%, n = 60)  (Figure 4). Twenty-two percent (n = 24) of respondents strongly agreed and 32% (n = 35) agreed that a carcass grading system would benefit the U.S. bison industry.

Table 3.

Likert scale summary of responses regarding respondent perceptions of bison meat quality (n = 110).

Question or statement	Strongly agree % (n)	Agree % (n)	Neither agree nor disagree % (n)	Disagree % (n)	Strongly disagree % (n)	Do not know % (n)	No response % (n)
There are quality differences between grass- and grain-finished bison	41 (46)	37 (41)	14 (16)	2 (3)	0 (0)	3 (4)	0 (0)
Grass-finished bison should be marketed as a premium product	25 (28)	25 (28)	22 (25)	14 (16)	10 (11)	1.8 (2)	0 (0)
A carcass grading system for bison would benefit the U.S. bison industry	22 (24)	32 (35)	29 (32)	7 (8)	3 (4)	4 (5)	1.8 (2)
Bison is marketed appropriately based on its unique characteristics	20 (23)	62 (69)	8 (9)	4 (5)	2 (3)	0.9 (1)	0 (0)

Figure 4.

Percentage of selected responses collected from respondents concerning attributes of bison that provide added value to consumers (n = 110). Multiple responses were allowed.

Live Animal and Carcass Data

Benchmarking

This study was conducted from November 2021 to December 2022. A total of 72 lots were evaluated from three bison processing facilities in the United States over 23 data collection days and a total of 2,284 bison (bulls: n = 1,101; cows: n = 199; heifers: n = 984) were included in the study. Nine animals arrived dead (in the truck), and four had to be euthanized prior to slaughter due to handling difficulties. It is important to note that the incidents of animals arriving dead or needing to be euthanized outside the processing facility (holding pens) were not isolated for a single day but occurred throughout the project. Of the bison evaluated in this experiment, only 0.56% of bison scored an abnormal mobility score. Approximately 10% of the bison were electrically prodded before being restrained in the knock box or restrainer. Ninety-one percent of the bison (n = 2,022) had a hide mud coverage (Table 4) visual score of 1 (less than 1/3 of the hide was covered). Only 0.35% (n = 8) of bison grunted while restrained and 32 % (n = 728) of bison forcefully head bumped when restrained in the holding chute. The average blood splash in this study was 4.3%. Sixty-eight percent of bison (n = 1,556) did not head bump at all, 29.6% (n = 676) head bumped between 1 and 5 times, 1.7% (n = 39) head bumped between 6 and 9 times, and 0.5% (n = 13) head bumped 10 or more times.

Table 4.

Antemortem and postmortem measurements obtained from bison in three separate processing plants included in the study.

		n	% of total
Antemortem	Mud Scorea
	1	2,088	91.46
	2	192	8.41
	3	3	0.13
	Grunt
	No	2,276	99.65
	Yes	8	0.35
Postmortem	Blood splash
	No	2,185	95.67
	Yes	99	4.33
	Bruisedb
	No	71	3.11
	Yes	2,213	96.89
	Multiplec
	No	66	2.98
	Yes	2,147	97.01

^aScale from 1 to 3 (1 = less than 1/3 mud coverage, 2 = between 1/3 and 2/3 mud coverage, 3 = more than 2/3 mud coverage).

^bPercent of bison that had at least one bruise with a size at least between 0.1 and 7.62 cm in the whole carcass.

^cPercent of bison that had more than one bruise with a size at least between 0.1 and 7.62 cm in the whole carcass.

The average distance bison traveled from the producer to the slaughter processing facility was 823.7 ± 583.6 km (mean ± SD; Table 5). The average live weight was 455.8 ± 75.1 kg (mean ± SD). The average hot carcass weight was 276.4 ± 49.7 kg (mean ± SD), and the average cold weight was 271.0 ± 49.1 kg. The dressing percentage (mean ± SD) was 60.5 ± 3.3%. The average fat thickness (mean ± SD) was 1.4 ± 1.1 cm. Average bison ribeye area was 62.6 ± 9.8 cm² (mean ± SD). The average L* value for bison longissimus thoracis was 32.9 ± 2.8 (mean ± SD), the average a* value was 18.4 ± 2.2, and the average b* value was 12.7 ± 1.9 (Table 5).

Table 5.

Means of antemortem and postmortem measurements obtained from bison in three separate processing plants included in the study.

	Attribute	n	Mean	Std Dev	Min	Max
Antemortem	Distance traveled (km)	2,284	823.7	583.6	39.7	2,159.6
	Live weight (kg)	2,280	455.8	75.1	173.6	978.2
	Number of head bumpsa	2,284	0.7	1.5	0.00	14.0
Postmortem	Hot weight (kg)	2,283	276.4	49.7	73.0	622.3
	Cold weight (kg)	2,183	271.0	49.1	73.0	617.2
	Dressing %	2,279	60.5	3.3	32.2	70.9
	Fat thickness (cm)	2,274	1.4	1.1	0.0	8.1
	Ribeye area (cm2)	2,274	62.6	9.8	14.8	93.5
	L*	2,275	32.92	2.85	18.52	57.02
	a*	2,275	18.41	2.28	9.90	33.29
	b*	2,275	12.75	1.94	1.99	29.95

^aPercentage of bison that forcefully and intentionally hit the inner surface of the chute at least one time.

Bruising

Approximately 97% percent of the bison, in this study, had at least one bruise. Specific percentages for each bruise size and location by sex class are presented in Table 6. Heat maps (Figure 5) demonstrate the frequency of bruising across different carcass regions by sex class. All sex classes had prominent bruise frequency on two bruise sections in the caudal side of the carcass toward the medial plane (R6 and L6). Bulls had more bruising on their dorsal process compared to the rest of their body. Cows and heifers had a numerically higher frequency of bruising on the lateral frontal sides of their carcasses (4R and 4L) compared to bulls.

Table 6.

Total percentage of bruises in bison categorized by carcass location, size, and sex class. Bruises were categorized into a 1 to 4 ordinal scale based on 7.62 cm increments and further separated by sex class (bull, cow, and heifers). R denotes the right side of the carcass and L denotes the left side of the carcass and the number presents the location of the bruise as followed in the methodology.

Location		0 No bruise	1 (0.1 to 7.62 cm)	2 (7.62 to 15.24 cm)	3 (15.24 to 30.48 cm)	4 (>30.48 cm)
R1	Bull	93.37	3.27	1.82	1.27	0.27
	Cow	85.93	2.51	5.03	2.51	4.02
	Heifer	88.41	5.08	2.85	2.34	1.32
R2	Bull	87.65	4.09	5.00	2.72	0.05
	Cow	84.42	5.53	4.52	1.51	4.02
	Heifer	84.15	6.50	5.39	3.15	0.81
R3	Bull	86.65	5.09	4.18	3.27	0.82
	Cow	73.87	5.03	8.54	7.54	5.03
	Heifer	75.30	9.76	6.61	6.00	2.34
R4	Bull	74.21	11.63	7.81	5.63	0.73
	Cow	58.29	9.05	12.06	11.06	9.55
	Heifer	49.80	18.70	16.87	9.76	4.88
R6	Bull	36.97	26.07	30.06	6.63	0.27
	Cow	23.12	16.08	36.68	20.60	3.52
	Heifer	41.46	25.10	26.32	6.91	0.20
R7	Bull	83.56	8.45	5.09	2.45	0.45
	Cow	74.87	9.05	9.55	4.52	2.01
	Heifer	69.82	12.80	11.38	4.78	1.22
R8	Bull	87.38	5.54	4.27	1.63	1.18
	Cow	63.82	5.53	12.56	9.05	9.05
	Heifer	75.20	7.11	6.30	6.00	5.39
5A	Bull	61.49	12.99	9.99	9.17	6.36
	Cow	76.88	5.53	9.05	4.02	4.52
	Heifer	49.49	11.99	12.40	12.09	14.02
5B	Bull	54.59	3.00	3.45	9.63	29.34
	Cow	78.39	3.52	4.02	3.52	10.55
	Heifer	63.62	2.64	4.37	6.91	22.46
5C	Bull	44.41	3.91	5.45	13.71	32.52
	Cow	70.85	4.52	5.53	8.04	11.06
	Heifer	49.09	3.15	7.01	12.80	27.95
L1	Bull	90.10	4.90	2.45	2.18	0.36
	Cow	88.44	2.01	3.52	4.02	2.01
	Heifer	86.89	5.69	3.66	2.54	1.22
L2	Bull	88.74	3.09	4.72	2.27	1.18
	Cow	81.41	4.52	6.03	5.03	3.02
	Heifer	83.13	7.22	4.37	3.05	2.24
L3	Bull	86.56	4.36	3.09	4.54	1.45
	Cow	70.35	6.03	5.03	9.55	9.05
	Heifer	71.04	12.09	7.42	6.20	3.25
L4	Bull	78.84	8.45	6.99	4.54	1.18
	Cow	55.28	8.04	13.07	9.05	14.57
	Heifer	55.89	13.01	14.43	11.28	5.39
L6	Bull	42.14	24.52	27.34	5.90	0.09
	Cow	23.12	17.59	38.69	19.10	1.51
	Heifer	43.29	26.63	22.97	6.71	0.41
L7	Bull	82.11	8.36	6.99	2.18	0.36
	Cow	75.38	5.53	8.54	7.04	3.52
	Heifer	66.67	11.99	12.50	6.91	1.93
L8	Bull	88.19	4.45	3.81	2.45	1.09
	Cow	75.38	4.02	4.52	7.54	8.54
	Heifer	74.19	7.22	7.62	5.79	5.18

Figure 5.

Bison bruise heat map with redder sections representing higher percentage that had at least one bruise with a minimum size between 0.1 and 7.62 cm.

Linear regression

Factors associated with dressing percentage were ribeye area, fat thickness, sex class, plant, and bruise score (P < 0.05; Table 7). Greater ribeye area and fat depth were associated with greater dressing percentage (P < 0.0001). Additionally, bruise score was also associated with slightly higher dressing percentages (P = 0.0431). Cows had reduced dressing percentage compared to heifers (P < 0.0001).

Table 7.

Linear regression parameter estimates for dressing percentage, ribeye area, and fat thickness of bison.

Term	Estimate	Std. Error	P value
Dressing percentage
Intercept	53.2402	0.5189	<0.0001
Ribeye area	0.5975	0.0376	<0.0001
Fat thickness	1.2480	0.1463	<0.0001
Bruise score	0.50021	0.2471	0.0431
Sex class (heifer)	Referent
Sex class (bull)	−0.0280	0.1580	0.8593
Sex class (cow)	−0.9921	0.2435	<0.0001
Plant [1]	Referent
Plant [2]	1.5395	0.4157	0.0005
Plant [3]	−0.5974	0.3398	0.0845
Ribeye area
Intercept	4.22426	0.2676	<0.0001
Sex class (heifer)	Referent
Sex class (bull)	0.4237	0.0752	<0.0001
Sex class (cow)	−0.5233	0.1131	<0.0001
Live weight	0.00503	0.0002	<0.0001
Plant [1]	Referent
Plant [2]	−0.175	0.1469	0.2385
Plant [3]	0.60061	0.1201	<0.0001
Fat thickness
Intercept	−0.6591	0.0754	<0.0001
Sex class (heifer)	Referent
Sex class (bull)	−0.3451	0.0215	<0.0001
Sex class (cow)	0.0873	0.0332	0.0088
Live weight	0.00125	6.41E−05	<0.0001

Factors associated with (P < 0.05; Table 7) the ribeye area were sex class, plant, and live weight. Greater live weight was associated with greater ribeye area (P < 0.0001). Bulls had greater ribeye areas compared to heifers (P < 0.0001), and cows had lower ribeye areas compared to heifers (P < 0.0001).

Factors associated with (P < 0.05; Table 7) fat thickness were sex class and live weight. As live weight increased (P < 0.0001) fat thickness increased. Bulls had decreased fat thickness compared to heifers (P < 0.0001) whereas cows had greater fat thickness compared to heifers (P = 0.0088).

Factors associated with (P < 0.05; Table 8) L* were plant, fat thickness, ribeye area, number of head bumps in the chute, distance traveled, and sex class. The greater the fat thickness (P < 0.0001), ribeye area (P < 0.0001), and number of head bumps in the chute (P = 0.001), the higher the L* values.

Table 8.

Linear regression parameter estimates for objective color measurements of bison.

Term	Estimate	Std Error	P value
L*
Intercept	30.3097	0.5145	<0.0001
Ribeye area	0.2643	0.0453	<0.0001
Fat thickness	1.13862	0.1741	<0.0001
Sex class (heifer)	Referent
Sex class (bull)	−0.1634	0.1676	0.3301
Sex class (cow)	−0.4381	0.2461	0.0762
Number head bumps	0.113	0.0344	0.001
Distance traveled	−0.0011	0.0004	0.014
Plant [1]	Referent
Plant [2]	0.0061	0.2893	0.9832
Plant [3]	−0.679	0.2282	0.0044
a*
Intercept	13.3461	0.4752	<0.0001
Ribeye area	0.2349	0.0353	<0.0001
Fat thickness	1.0406	0.1346	<0.0001
Sex class (heifer)	Referent
Sex class (bull)	−0.6964	0.1337	<0.0001
Sex class (cow)	−0.0183	0.1886	0.9225
Number of head bumps	0.0589	0.0246	0.017
Live weight	0.0023	0.0004	<0.0001
Plant [1]	Referent
Plant [2]	0.3686	0.2333	0.1196
Plant [3]	−0.6233	0.1922	0.0019
b*
Intercept	8.8879	0.4144	<0.0001
Ribeye area	0.1761	0.0313	<0.0001
Fat thickness	0.8123	0.1197	<0.0001
Sex class (heifer)	Referent
Sex class (bull)	−0.6732	0.1191	<0.0001
Sex class (cow)	0.2286	0.1665	0.1708
Number of head bumps	0.0647	0.0219	0.0032
Live weight	0.0017	0.0004	<0.0001

Factors associated with (P < 0.05; Table 8) a* were plant, number of head bumps in chute, ribeye area, live weight, fat thickness, and sex class. The greater the number of head bumps in the chute (P = 0.017), ribeye area (P < 0.0001), live weight (P < 0.0001), and fat thickness (P < 0.0001) the greater the a* values after 1 h of bloom time. Bulls and cows had lower a* values as compared to heifers (P < 0.0001).

Logistic regression

Season, sex class, live weight, and plant were associated with bruising (P < 0.05; Table 9). The odds of being bruised increased as live weight increased, with an odds ratio (OR) of 1.003 and a confidence interval (CI) range of 1.0012 to 1.005. Additionally, the odds of being bruised were greater in cows as compared to heifers (OR: 3.561, CI: 1.604, 12.005) and lower for bulls compared to heifers (OR: 0.298, CI: 0.151, 0.505). The odds of being bruised decreased in Fall compared to Winter (OR: 0.228, CI: 0.185, 0.434) but there was no evidence of a difference between Summer and Spring when compared to Winter (P = 0.7691 and P = 0.0573, respectively).

Table 9.

Logistic regression odds ratios for bruising and blood splash in bison.

Term	Estimate	Std. Error	Odds ratio	95% confidence interval		P value
				Low	High
Bruising
Intercept	1.8144	1.0644	6.1375	0.7823	51.4091	0.0883
Live weight	0.0033	0.0011	1.0033	1.0012	1.00554	0.0025
Sex class (heifer)	Referent
Sex class (bull)	−1.2089	0.2958	0.2985	0.1517	0.5058	<0.0001
Sex class (cow)	1.2702	0.4873	3.5617	1.6046	12.0054	0.0091
Plant [1]	Referent
Plant [2]	1.4451	0.4887	4.2425	1.9004	14.321	0.0031
Plant [3]	−0.9873	0.2753	0.3725	0.1947	0.601	0.0003
Season (Winter)	Referent
Season (Spring)	0.5623	0.2957	1.7547	1.0094	3.2652	0.0573
Season (Summer)	−0.0806	0.2749	0.9224	0.5473	1.6279	0.7691
Season (Fall)	−1.2435	0.2159	0.2883	0.1856	0.4348	<0.0001
Blood splash
Intercept	−6.2296	0.8145	0.0019	0.0003	0.0096	<0.0001
Live weight	0.0018	0.0006	1.0018	1.0004	1.0031	0.0086
Number of head bumps	0.1277	0.0526	1.1362	1.0174	1.2528	0.0152
Plant [1]	Referent
Plant [2]	0.8001	0.233	2.2258	1.4592	3.7404	0.0006
Plant [3]	0.7062	0.2255	2.0264	1.356	3.3721	0.0017
Season (Winter)	Referent
Season (Spring)	0.566	0.3082	1.7612	1.026	3.8238	0.0663
Season (Summer)	1.3079	0.2899	3.6984	2.2722	7.8787	<0.0001
Season (Fall)	0.4022	0.3014	1.4952	0.887	3.2225	0.182

Season, live weight, plant, and number of head bumps in the chute were associated with blood splash in bison longissimus thoracis (P < 0.05; Table 9). The odds of having blood splash increased with live weight (OR: 1.001, CI: 1.000, 1.003). The odds of blood splash increased with a number of head bumps in the chute (OR: 1.136, CI: 1.017, 1.252). The odds of having blood splash were higher in the Summer (OR: 3.698, CI: 2.272, 7.878) but there was no difference between Spring and Fall (P = 0.0663 and P = 0.1820, respectively).

Discussion

Survey

The NBA is a nonprofit national organization representing stakeholders across the bison supply chain. Most of the respondents in this study worked for more than one sector of the industry (e.g., both as cow–calf producers and finishers). This is different compared to the beef industry, where the producers are mostly segmented into cow–calf producers, finishers, packers, and retailers and tend to work separately (Buhr and Kim, 1997). More than half of the respondents had been working in the industry for more than 10 yr, suggesting that most of the individuals have long-term involvement in the bison industry. The majority of the stakeholder businesses were located in the Midwest and West regions of the United States, indicating a concentration of the bison industry in those regions. Most individuals employed in the bison industry are identified as white men, constituting 73% (n = 80) of the survey population. The average age for stakeholders was 53 yr old, with a maximum age of 85 yr and a minimum of 22 yr.

Most survey respondents agreed that the bison industry should continue to expand. The increase in the bison slaughter numbers over recent years indicates that the industry has been steadily growing (USDA, 2024a). Respondents indicated that the bison industry would benefit from enhancements in marketing, animal health, animal welfare, and production costs. Although details were not asked about marketing needs, an example of an area where increased marketing efforts could be beneficial is in the nutritional information about bison products. However, the majority of the individuals either strongly agreed or agreed that bison is appropriately marketed based on its unique characteristics. This suggests that even though the majority of respondents agreed that bison meat is appropriately marketed these individuals are invested in the growth and continuous improvement of the bison industry and so are likely always looking for innovative ways to promote and market their products. Bison meat is a healthy lean protein source (McDaniel et al., 2013; USDA, 2022a, 2022c), and it is important that consumers recognize the nutritional value of these products. Yang and Woods (2013) investigated the effects of knowing the nutritional value of bison ground meat on consumer willingness to pay and indicated that some consumers do not know about the benefits of consuming bison as compared to other animal proteins. Moreover, consumers who knew about the nutritional value of bison meat were willing to pay $2.68 to $2.81 more (from the total price) for these bison ground products. These findings are also in agreement with Qasmi et al. (2015), who also found that providing nutritional information about the product significantly increased consumer willingness to pay for ground bison. Similarly, a survey in Canada reported that consumers associated bison meat with terms such as “lean”, “game” and “expensive”, but most participants had never consumed it or would only consume it on special occasions (Popoola et al., 2021).

In this study, bison stakeholders indicated that animal welfare was critical to produce bison meat and that it directly affected the quality of the product. It is well documented that inappropriate welfare, handling, and transportation can have negative effects on meat quality in beef (Xing et al., 2019; Carrasco-Garcia et al., 2020; Diro et al., 2021; Sullivan et al., 2022). Additionally, stressed bison could be potentially hazardous for animal handlers; however, there is limited data on bison workers’ injuries (Duysen et al., 2017). Bison are readily agitated, and they tend to have a sizable flight zone (Rioja-Lang et al., 2019) sometimes making them more challenging to handle, particularly when stressed. This represents a challenge for bison producers because bison generally must be transported to the slaughter plant and restrained prior to harvesting. This process requires several human–animal interactions that even if performed in a proper manner can be stressful for the animals. Moreover, a challenge with bison is that they tend to herd side by side. This can lead to animals crowding in the single-file chute (Grandin and Deesing, 2014) which is used in many handling facilities. There is currently very limited research on the effects of transportation on bison animal welfare. Survey respondents suggested that improvements in facility design, animal handling, employee training, and transportation duration should be made to meet and maintain optimal animal welfare standards in the bison meat production system. Therefore, more research is needed to develop new strategies that could be applied to enhance bison animal well-being and overall meat quality during the marketing process.

The meat derived from bison is characterized by a dark red color and typically exhibits a low degree of intramuscular fat content (Koch et al., 1995; McDaniel et al., 2013). Approximately half of respondents agreed that grass-fed bison should be marketed as premium; however, a quarter of respondents disagreed with this statement. Fat content and type are considered important factors in developing desired meat flavors (Calkins and Hodgen, 2007). In the current survey, leanness was not the most selected meat quality attribute. Instead, respondents in the current study identified flavor as the most important quality attribute of bison meat products. Bison has been characterized to have a strong aroma and aftertaste, and was still ranked as high as beef and greater than elk on a consumer overall liking preference test (Popoola et al., 2019). Moreover, bison meat has been associated with positive terms such as “lean” and “nutritious” (Popoola et al., 2019). Because feeding regimens affect the fatty acid profile and content of bison (Rule et al., 2002), additional research could show the potential of feeding strategies in altering the nutritional composition of bison meat, thereby yielding benefits for the industry.

The NCBA has been using the NBQA data to continuously improve the beef industry’s quality since the early 1990s. Over time, the focus of the NBQA has expanded from traditional attributes of beef quality to include indicators of animal welfare such as cattle mobility, live animal defects, and carcass bruising (Eastwood et al., 2017). This research initiative serves as a baseline for the U.S. beef industry, benchmarking meat quality and welfare attributes of cattle arriving at slaughter plants approximately every 5 yr. It also records outcomes such as mobility upon arrival at the plant, cattle breeds, carcass bruising, quality grades, and yield grades (Shook et al., 2008; Eastwood et al., 2017; Harris et al., 2018). In addition to in-plant data collection, the NBQA actively collects stakeholder input. This process provides a deeper understanding of the current challenges and perceptions of the beef industry. It successfully identifies stakeholder perceptions of animal management and meat quality through surveys and in-person interviews (Shook et al., 2008; Boykin et al., 2017). This comprehensive approach allows for the timely identification of the industry’s needs which are constantly changing. Information obtained from the NBQA has been used to support the continuous improvement of quality and value across all sectors of the beef supply (Moore et al., 2012). In contrast, the bison industry does not have a similar mechanism to collect and understand stakeholder perceptions of successes, challenges, and needs.

The beef industry has been able to narrow the gap between expected eating experience and the actual eating experience by developing the USDA quality grading system (Liu et al., 2022). The United States grading system for beef segregates carcasses into different quality grades, primarily, prime, choice, and select. There is currently no official grading system for bison meat in the United States. Canada has a grading system that evaluates bison carcasses based on animal maturity, muscling, muscle color, external fat color, and fat depth. This system has 10 quality grades (A1–4, B1–3, and D1–3) separated into two different maturity classes: Maturity Class I = youthful, includes A1–4 and B1–3; and Maturity Class II = mature, includes D1–3 (Janssen et al., 2021). In the current study, approximately one-third of respondents neither agreed nor disagreed that a grading system would benefit the United States bison industry. However, approximately half of the respondents agreed that a carcass grading system could benefit the United States bison industry. Potential challenges associated with a bison meat grading system are that to have a grading system there needs to be more consistency in meat quality and a market for graded products. A carcass grading system could be challenging to develop because bison steaks have very little marbling compared to traditional fed cattle (Ding et al., 2016). If the differences between products are not easily detectable, it can be challenging to categorize meat based on these characteristics. If a grading system were to be developed it would likely need to include other quality attributes other than marbling.

Antemortem and postmortem outcomes

In this study, bulls (48.2%) represented the majority of bison observed, followed by heifers (43.1%), and cows (8.71%). Although not directly quantified, the majority of bison included in this study were grain-fed. The USDA National Monthly Bison Report (USDA, 2023c) reported that the U.S. grain-fed bison population had a similar distribution with the majority of bison being bulls (67.7%) followed by heifers (28.29%) and aged cows (3.9%). Average carcass weights were numerically similar between this study (276.4 kg) and the USDA National Monthly Bison Report (266 kg; USDA, 2023c). Thus, the current study population is representative of the current U.S. bison industry.

Animals are exposed to multiple stressors during transportation to the slaughter plant (Deters and Hansen, 2020). During this process, cattle can experience a wide variety of conditions such as unfamiliar environments, comingling with unfamiliar animals, food and water deprivation, loud noises, and extreme temperatures (Edwards-Callaway and Calvo-Lorenzo, 2020). In this study, the average distance bison traveled was 823 km. Multiple producers included in this study raised bison in Canada to be slaughtered in the United States and likely explains, in part, the long transport distance. According to the USDA National Monthly Bison Report (2023a), a total of 2,753 bison were exported just during the month of November from Canada to be slaughtered in the United States. Additionally, because the bison industry is relatively small (USDA, 2022a; 2023a; 2024a), there are fewer options to where producers can ship their animals, and thus bison may need to travel greater distances to be processed. Nielsen et al. (2011) reported that increased distance traveled can increase the risk of injury in multiple species such as poultry, sheep, cattle, and horses, and thus it is important to evaluate animal welfare upon arrival at the plant. Additionally, McCorkell et al. (2013) found increased trim loss (from bruising) on bison that were transported in comparison with bison that were slaughtered on-farm. In this study, as distance traveled increased, L* of bison longissimus thoracis decreased. Previous studies have also demonstrated the same inverse relationship between distance traveled with L* values in cattle (Vimiso and Muchenje, 2013). Stress can change multiple physiochemical parameters in muscle leading to a high ultimate pH (Lahucky et al., 1998). In beef, such high ultimate pH leads to muscles that are darker in color with lower L* value compared to normal pH muscles (Hughes et al., 2017).

Animal mobility is commonly used in the cattle industry to evaluate welfare both on-farm and at the slaughter plant (Edwards-Callaway and Calvo-Lorenzo, 2020; BQA FA, 2021; Mijares et al., 2021). Only 0.5% of bison in the current study had an abnormal mobility score. During this study, four bison had to be euthanized outside the processing facility (in holding pens or single file), but not because of mobility challenges. Sometimes bison can be challenging to move and to reduce stress from more intensive handling and prevent animals from becoming more agitated and potentially riskier to handle, plant employees may elect to stun the animal prior to entering the restraint area.

In addition to mobility, several animal handling metrics were recorded during this study. The most common handling tools used for moving bison during this experiment were sorting paddles. Electric prods were not used as the primary driving tool. There is a limited amount of data regarding electric prod use in bison. In this study, approximately 10% of bison were electrically prodded before being restrained in the knock box or restrainer. The beef industry has been able to reduce electric prod use in feedlots and slaughter facilities by raising awareness around best animal handling practices and in-plant audits utilizing the guidelines and audit tool from the North American Meat Institute (NAMI, 2021). Developing more handling guidelines and audit tools specific to bison could be a valuable resource for the industry.

Vocalization has been used as a reliable indicator of beef cattle distress (Watts and Stookey, 1999; Davis et al., 2022). In this study, grunting was assessed in individual bison in the handling area prior to and during stunning. Only 0.3% of bison grunted before being slaughtered. Anecdotally, plant employees have shared that bison rarely vocalize while they are being moved through the facilities. Vocalization may not be an appropriate indicator of bison stress. Overall, these handling measurements highlight the use of low-stress handling practices in all three plants included in the study.

The last handling parameter measured was head bumping in the chute or at the single-file door prior to restraining. This behavior is worth exploring in future studies as it occurred frequently in this study, with head bumping observed in one-third of the bison. From the plants analyzed, two plants had knock boxes. So, in this design, animals could bump their heads into the front of the knock box. The other plant had a center-track restrainer; in this plant, the bison head bumped at a single-file door before the restrainer. In this study, the number of head bumps was associated with a greater probability for blood splash. This could be because the force exerted back by the chute surface during head bumping can travel through the animal’s spine, potentially bursting blood vessels. Linear regression results indicated that the number of head bumps in the chute also resulted in increased L*, a*, and b* values. To the authors’ knowledge, this has not been reported elsewhere and further work is needed to understand the reasons for bison head bumps and their impact on quality.

Mud has been recognized as a factor that could potentially impact animal welfare, behavior, and performance in cattle (Morrison et al. 1970; Grandin, 2016; Dickson et al. 2022). Currently, the NBQA evaluates mud/manure based on the location on the animal and the proportion of coverage (none, small, moderate, large, and extreme; Eastwood et al., 2017). Mud coverage is of high importance because manure or mud can act as a transportation means for bacteria and could potentially be introduced in meat products generating a higher risk of contamination (Hauge et al., 2012). The majority of bison in the current study had minimal mud coverage (less than 1/3 of hide-covered). Similarly, in the 2016 NBQA, it was reported that 70.3% of cattle had small mud coverage and 22.9% had moderate mud coverage (Eastwood et al., 2017). Eastwood et al. (2017) suggested that the difference in mud scores by location during their quality audit (legs 40.8%, belly 33.0%, tail region 15.5%, side 6.8%, and top-line 3.9%) and the previous audit by McKeith et al. (2012) (legs 36.8%, belly 23.7%, tail region 13.7%, side14.9%, and top-line 11.0%) are likely due to seasonality effects. In the current study, no seasonal effects were observed in bison mud scores. Based on the findings in this study, mud coverage may not represent a welfare challenge for the bison industry because it remains low for the majority of bison regardless of season.

A bruise is defined as the rupture of vascular supply in tissues that allows for the accumulation of blood and serum typically after trauma that did not cause external laceration (Hoffman et al. 1998). Approximately 97% percent of bison in the current study had at least one bruise, and the vast majority of bruised bison had multiple bruises. Bruises along the dorsal midline were frequent for all bison. These results are similar to those of Hoffman and Luhl (2012), who found high bruise percents on the rump sections of the beef carcasses and suggested that it may be due to high truck densities. Previous studies also suggest that both preslaughter handling and sex class can influence bruising (Jarvis et al., 1995). In this study, greater odds of being bruised were related to sex class, plant, and season. In the current study, bison cows had increased odds of being bruised as compared with heifers. These results are in agreement with Yeh et al. (1978) who identified that beef cows had greater bruising and a greater amount of trim loss compared to bullocks. Additionally, Kline et al. (2020) reported that beef cows had a greater frequency of bruising than steers. Distance traveled did not influence the probability of bruising in this study. Typically, both male and female bison have horns (Vervaecke et al., 2005). Horns could cause bruising during the handling, loading, and transporting of bison because they provide a small surface area on which low amounts of force could produce high pressures capable of bruising or piercing muscles. The presence of horns can further influence meat safety. Muscle is considered essentially sterile on the inside (Gill et al., 1978); however, if a horn penetrates, the muscle is no longer considered sterile, and it should be trimmed off from the carcass. Additionally, after a trauma, muscle sustains a higher pH that can support the growth of spoilage bacteria (Cruz-Monterrosa et al., 2017). Moreover, an increase in carcass bruising has been related to lower dressing percentages (because bruises are removed from the carcass during trimming) and inferior meat quality in cattle (Warner et al., 1998).

According to the USDA beef carcass price equivalent index value (USDA, 2024b) choice steer and heifer dressing percentages were 62.4% and 62.2%, respectively. In this study, bison had a slightly lower dressing percentage averaging 60.5%. These results are contradictory to Koch et al. (1995) who reported that bison (Bison bison) had a greater dressing percentage than beef (Bos taurus) cattle (62.6% in bison vs. 60.7% in beef). Koch et al. (1995) reported their average bison live weight as 431.3 kg which is numerically similar to the average live weight (455.8 kg) in this study. Variations in dressing percentage can be impacted by many variables. In this study, sex class, ribeye area, plant, bruising, and fat thickness were associated with changes in dressing percentage. Unexpectedly, bruise presence was associated with greater dressing percentages but the magnitude of difference between bruised and unbruised carcasses was minimal. Further research on bruise size and trimming weights could potentially explain the effect of bruising on dressing percentage of bison. Other studies have indicated that factors such as animal age, diet, and sex class could also affect cattle dressing percentage (Coyne et al., 2019).

Chronic antemortem stress in cattle can negatively influence meat quality (Vimiso and Muchenje, 2013), reducing the amount of glycogen in muscle resulting in meat with a high pH (>5.8) and a darker color (Mounier et al., 2006). Acute antemortem stress can also affect meat quality (Warner et al., 2007) and can lead to pale soft and exudative like condition during which pH declines rapidly at high temperatures resulting in protein denaturation producing higher initial L* and a* values (Sammel et al., 2002; Nair et al., 2016). In this study, longer distance traveled was associated with lower L* values. The linear regression estimate represented only a 0.0011 unit decrease in L* values per unit (km) of distance traveled. However, as the average distance traveled in this study was high (823.7 ± 583.6 km), changes in L* values could be indicative of a relationship between distance traveled and chronic stress, because of the cumulative effect each km has on the L* value. Additionally, the number of head bumps in the chute was associated with greater L* values possibly due to acute stress muscle metabolism. Therefore, multiple antemortem factors such as distance traveled, plant, number of head bumps in the chute, and fat thickness can influence L* values in bison meat.

Color is one of the most important quality attributes of meat that influences consumer purchase decisions (Suman et al., 2014). Linear regression indicated the factors associated with greater (a* values) were plant, fat thickness, ribeye area, number of head bumps in the chute, and live weight. Multiple factors such as genetic background, sex, age, diet, and breed can impact meat color (Raes et al, 2003). Additionally, the difference in the processing and chilling conditions could have contributed to the variation in a* values between the plants. Another factor that could have an influence on meat color is the Rinse & Chill (Rinse & Chill, WI, USA) technology used in one of the plants. This technology is used to circulate a cold solution composed of approximately 98.5% water and 1.5% mixture of dextrose, maltose, and sodium phosphates through the bison’s vascular system, which could affect the appearance of the meat (Hwang et al., 2022). Research suggests that Rinse & Chill results in meat with lower pH, longer sarcomere length, improved redness after blooming, and lower shear force values when compared to traditional chilling methods (Kethavath et al., 2022). Bison meat has a greater concentration of polyunsaturated fatty acids compared to beef and typically undergoes rapid discoloration (Galbraith et al., 2016; Roberts et al, 2017; Hasan et al. 2021). This could be a reason why bison meat is commonly sold in vacuum packages (Pietrasik et al., 2006). Since the vacuum bags have little to no oxygen, myoglobin is in the deoxy-myoglobin state resulting in a purple color (Seideman et al., 1984). Studies have found that if consumers are educated about beef color in a vacuum package, they are more likely to purchase vacuum-packaged products compared to uneducated consumers (Lynch et al., 1986). Therefore, consumer education could be an area of opportunity for the bison meat industry.

The average ribeye area for bison in the current study was 62.6 cm² which is much lower than the average ribeye area (89.5 cm²) for fed beef reported in the 2016 NBQA (Boykin et al., 2017). Linear regression indicated that the factors associated with greater ribeye area were live weight, sex class, and plant. Previous studies in beef have also indicated that carcass weight can be correlated with greater ribeye areas (Boykin et al., 2017). However, greater carcass weights do not always result in larger ribeye areas (Moore et al., 2012).

Conclusion

Bison meat production continues to increase steadily over the years in the United States. Most of the bison stakeholders want the industry to continue to expand and grow. Animal handling, bison behavior, employee training, facility design, and transportation duration were identified as the most critical factors that impact animal welfare in the bison production system. Moreover, the stakeholders understood that animal welfare is a critical component for bison production and that it directly affects meat quality. Approximately half of the participants agreed that a quality grading system would benefit the United States bison industry; however, a relatively high proportion of participants were neutral (neither agree nor disagree) with this statement. Future work could benefit from asking more detailed questions about the resources necessary for industry growth, such as industry funds for marketing, consumer insight research, and new product development.

This study benchmarks the live animal and carcass characteristics of bison. Multiple live animal characteristics and process facility factors such as distance traveled, season, number of head bumps in the chute, sex class, live weight, fat thickness, and ribeye area can influence meat quality parameters of bison. The current study did not measure animal age and diet, indicating a need for further research to understand other factors that could affect bison dressing percentage and meat color. Lastly, further investigation is needed to examine the factors that affect the ribeye area and its impact on meat quality attributes, such as tenderness. This comprehensive approach will ensure the industry’s continuous growth while maintaining high standards of animal welfare and meat quality.

Abbreviations

Abbreviations
 
• CIELAB

  Commission Internationale de I’Eclairage LAB

 
• NAMI

  North American Meat Institute

 
• NBA

  National Bison Association

 
• NBQA

  National Beef Quality Audit

 
• NCBA

  National Cattlemen’s Beef Association

 
• QR

  quick response

 
• USDA

  United States Department of Agriculture

Acknowledgments

This project (#3TR049) was made possible through the Center of Excellence for Bison Studies, a partnership among South Dakota State University, the National Bison Association, and the National Buffalo Foundation. Financial support was provided by the National Buffalo Foundation.

Conflict of interest statement

None declared.