Mycoplasmopsis (Mycoplasma) bovis is a significant pathogen in North American bison (Bison bison), causing severe disease with high morbidity and mortality. Effective serological diagnostics are essential for the surveillance and management of disease, yet commercially available ELISAs for M. bovis have only been developed for use in cattle and have not been validated in bison. In this study we evaluated a P48-based indirect ELISA for M. bovis detection and compared its diagnostic performance to a commercially available ELISA developed for use in cattle. Serum samples from bison were tested using both assays, and diagnostic metrics were assessed in comparison to infection status as confirmed by PCR and/or culture. The commercial ELISA demonstrated superior sensitivity (77.8%) and specificity (98.0%) compared to the P48 ELISA (63.9% sensitivity, 94.9% specificity). Combining both ELISAs slightly improved sensitivity (83.3%) but did not significantly enhance overall diagnostic performance. Both the P48 and commercial ELISAs also exhibited cross-reactivity with other Mycoplasma species. We identify significant challenges in serological diagnostics of M. bovis in bison with implications for interpretation of previous serological studies. Future research should focus on multiple immunogenic targets to enhance sensitivity and specificity for M. bovis serological surveillance.

Introduction Body size is a fundamental trait that influences survival, reproduction, and ecosystem functioning in large herbivores. Despite their ecological importance, our understanding of how North American bison (Bison bison) respond to climatic variation over time remains limited. Methods To address this, we analyzed a large dataset comprising more than 672,000 weight observations from 186,732 individuals collected over 20 years across 14 widely-dispersed geographic locations to investigate how climate, birth cohorts, and translocation practices shape bison growth dynamics. Using a three-parameter logistic model, we estimated asymptotic body mass (ABM) across seven quinquennial cohorts and correlated these estimates with local climatic conditions, specifically mean annual temperature (MAT) and precipitation (MAP). Results Bison ABM varied geographically in accordance with climate: individuals attained their greatest adult body masses in moderate climates (around 10–12°C MAT and 500–650 mm MAP), whereas both warmer-drier and cooler climates were associated with reduced ABM, as confirmed by a significant quadratic climate–size relationship (p < 0.01). Sexual size dimorphism was also highest under these moderate conditions, with males achieving disproportionately larger sizes than females in such environments. Significant cohort effects were detected, with certain birth year cohorts consistently exhibiting higher or lower ABM, likely reflecting the influence of early-life environmental conditions. Furthermore, animals that were translocated between localities exhibited changed growth patterns. Female bison translocated between herds showed growth trajectories that were intermediate between their herd of origin and their new destination, potentially indicating partial convergence to local size norms. Discussion This work supports the dominant influence of environmental conditions on bison body size, consistent with previous findings, while expanding our understanding on a broader spatial and temporal scale. Future management strategies should consider localized climate optima and the long-term impacts of translocation, ensuring that bison continue to fulfill their critical ecological roles in North America.

In this study, we examined Y chromosome morphology in three species: European bison (Bison bonasus), American bison (Bison bison), and domestic cattle (Bos taurus). Peripheral blood lymphocytes were cultured, and C-banded metaphase preparations were analyzed to measure key Y chromosome parameters-absolute and relative length, absolute and relative area, and heterochromatin (C-band) content-using ImageJ software (ver. 1.54p). All traits deviated from normality (Shapiro-Wilk, p < 0.05). Non-parametric analyses revealed significant interspecific differences, with the strongest effects observed for C-band, followed by absolute and relative length. Principal Component Analysis (PCA) indicated a two-class structure, where domestic cattle formed a distinct cluster, while European and American bison grouped closely but remained separable. Linear Discriminant Analysis (LDA) achieved high classification accuracy (0.94), with misclassifications limited to American versus European bison. Generalized Linear Model (GLM) analyses further confirmed a strong species effect on C-band content (R2 = 0.916). These results identify the C-band as the most powerful discriminant, providing robust morphological differentiation among the three species and demonstrating the value of Y chromosome morphometry for comparative cytogenetic studies. Due to the limited sample size of American bison (n = 2), interpretations for this species should be made with caution.

North American bison (Bison bison) face significant challenges to their recovery, including disease risks associated with translocation and genetic bottlenecks. This study aimed to achieve a multidisciplinary consensus on a definition of bison health and to identify key infectious disease concerns linked to bison translocation. A two-round Delphi survey was conducted with 12 of 22 invited experts representing public, tribal, nonprofit, and private sectors. Participants defined bison health as the ability of populations to express natural behaviors, demonstrate resilience to external stressors, and achieve high reproductive output within their environment with minimal intervention. Mycoplasma bovis was identified as a high-priority pathogen due to its severe economic and health impacts. This definition of bison health may be useful as a basis for guiding health monitoring and informing policy as well as identifying key needs of the bison sector.

As part of its mission to advance the field of wildlife endocrinology, the International Society of Wildlife Endocrinology aims to develop cost-effective antibodies and enzyme immunoassay kits that support research across a diverse range of species and sample matrices. To provide additional options for the quantification of faecal glucocorticoid metabolites (fGCMs), an antibody against 11-oxoetiocholanolone-17-carboxymethyl oxime (CMO) was generated in rabbits, and an enzyme immunoassay incorporating a horseradish peroxidase-conjugated label and 11-oxoetiocholanolone standard has been developed, designed for use with anti-rabbit IgG secondary antibody coated plates. This mini-kit was used to quantify glucocorticoid metabolites with a 5β-3α-ol-11-one structure in faecal extracts from 23 species: African and Asian elephants, Alpine chamois, American bison, Bengal tiger, blue wildebeest, blue-and-yellow macaw, brushtail possum, cape buffalo, fat-tailed dunnart, Florida manatee, ghost bat, giraffe, golden langur, Gould’s wattled bat, hippopotamus, Leadbeater’s possum, mandrill, okapi, roan antelope, samango monkey, short-beaked echidna, and western lowland gorilla. Pharmacological (adrenocorticotropic hormone challenge) and biological (inter-zoo translocation, wild capture, social disruption, illness/injury and veterinary intervention) challenges resulted in expected increases in fGCM concentrations, and in a subset of species, closely paralleled results from a previously established immunoassay against 11-oxoetiocholanolone-17-CMO. Two additional species tested, Krefft’s glider, which showed contradictory results on this assay compared to a previously validated enzyme immunoassay (EIA) and Ankole cow, where the magnitude increase post-event did not quite reach the 2-fold change criteria, highlight that differences in excreted faecal metabolites across species mean that no EIA will be suitable for all species. This assay provides a valuable new option for assessing adrenal activity across taxa using a group-specific antibody. Future studies should put similar emphasis on validation to determine optimal assay choice for measuring fGCMs in a variety of species.

Background: This study aimed to investigate rapid oxidation in poultry and fish myoglobin compared to livestock myoglobin using protein structural differences and bioinformatics tools. Methods: Myoglobins from beef (Bos taurus), bison (Bos bison), sheep (Ovis aries), goat (Capra hircus), red deer (Cervus elaphus), pork (Sus scrofa), chicken (Gallus gallus), turkey (Meleagris gallopavo), yellowfin tuna (Thunnus albacares), and tilapia (Oreochromis niloticus) were analyzed to understand differences in structure and function that may influence oxidative behavior. Results: Fish and poultry had shorter or absent D-helix in their myoglobin structure than other species. Tilapia showed the largest heme cavity surface area, indicating significant internal void space, while yellowfin tuna had the largest heme cavity volume, which could affect ligand binding dynamics compared with poultry and other livestock species. However, the heme solvent-accessible area was greater in chicken and turkey than in fish and other livestock species. Tuna myoglobin contains a cysteine and fish myoglobins have fewer amino acids compared to other species. Limited knowledge is currently available on the effects of proteoform, especially post-translational modifications, on the oxidation of myoglobin from different species. Conclusions: The bioinformatics approach used in this study suggests that, in addition to physiological reasons, shorter D-helix, larger heme cavity in tilapia and yellowfin tuna, and greater solvent-accessible area in poultry contribute to increased oxidation in myoglobin from poultry and fish compared with myoglobin from livestock species.

The North American bison (Bison bison) is gaining prominence in agricultural production systems across North America; however, comprehensive species-specific management guidelines, particularly regarding nutrition, remain limited. Vitamins and minerals are critical components of animal nutrition, playing essential roles in health maintenance and productivity. As bison production expands, the demand for precise nutritional benchmarks tailored to the species becomes increasingly evident. This scoping review aimed to (1) synthesize existing data on vitamin and mineral concentrations in bison tissues and (2) identify gaps in the current knowledge base to enhance bison health, welfare, and productivity. The review evaluated literature addressing vitamin and mineral profiles across various tissues in bison, while highlighting emerging areas of research, including the influence of environmental conditions and feeding systems (e.g., grass- versus grain-finished diets) on micronutrient status. Furthermore, although limited data were available, initial findings suggest sex and age do not impact micronutrient concentrations in bison tissues. These results underscore the need for further targeted research to refine and advance our understanding of micronutrient status of bison in order to develop a robust baseline data set to begin experiments to determine mineral and vitamin requirements for bison.

Grizzly Bear (Ursus arctos) predation on American Bison (Bison bison)—particularly calves—was likely once common.However, with the range-wide collapse of bison near the close of the 19th century, the two species no longer co-occur across much of their current distributions. Over the past 60 years, efforts to reintroduce bison to their native range have resulted in a few small areas where the two species once again co-occur. Yet, predation of bison by bears is apparently rare and has not been observed outside Yellowstone National Park, where both species have existed for millennia. On 28 June 2023, we observed an adult male Grizzly Bear protecting a buried bison calf that it had apparently killed in Yukon, Canada. This is the first observation of apparent predation of a bison by a Grizzly Bear outside Yellowstone National Park. Our observation further highlights how reintroduced bison are becoming integrated into local food webs, which is a key indicator of ecological restoration.

Mycoplasma bovis outbreaks in United States bison (Bison bison) herds: A case-control survey.

Abstract Sexual segregation is near ubiquitous in sexually dimorphic ruminants. Factors underpinning this phenomenon, however, continue to be debated. We conducted research on the spatial and social organization of American plains bison (Bos bison bison) on Antelope Island State Park, Utah, United States, to provide further insights into patterns and potential causes of sexual segregation. We examined 2 hypotheses associated with socially driven segregation: social factors and activity budget. We also investigated 2 ecological hypotheses: gastrocentric and predation. Our results did not support social segregation as a cause of spatial differences between sexes. Indeed, if social factors and activity patterns were driving segregation of the sexes, the spatial distribution of single-sex groups should have remained the same between seasons, and mixed-sex groups should not have been observed during parturition—outcomes contradictory to our results. Further, social hypotheses cannot explain why specific areas were used during sexual segregation, which requires an ecological explanation. Results from multi-response permutation procedure and overlap analyses illustrated significant spatial and elevational separation between male and female groups, which increased during parturition (a period of strong sexual segregation) and decreased during the mating season (a time of pronounced sexual aggregation). Male-only groups commonly used habitat on the northern end of the island, which was characterized by low elevation and heavy recreational use by humans. Before green-up of vegetation at high elevations, females used that habitat ostensibly to reduce predation risk. Later during parturition, females used southern and eastern areas of Antelope Island, where human recreational activity was low and vegetation was greenest. Those outcomes provide evidence supporting hypotheses for both predation risk and the gastrocentric model. This research can aid management of habitat and restoration of areas for bison, a species of conservation concern, and other wild ruminants by providing new insights into spatial use and social organization during 2 critical periods—parturition and rut.

The COVID-19 pandemic represents one of the most significant public health events of the last century. As with other coronaviruses (SARS, MERS) the role of animals is of intense interest. Believed to have originated in bats, the role of other animals in the epidemiology of the SARS-CoV-2 pandemic is still unclear, as is the range of susceptible hosts. American bison were intranasally infected with SARS-CoV-2 and monitored for seroconversion and the presence of viral RNA in oronasal secretions and feces. Although clinical signs were not seen, permissiveness of bison to infection with SARS-CoV-2 was manifest by seroconversion, the presence of viral RNA in oronasal secretions, persistence of viral RNA in lymphoid tissue, and viral associated interstitial pneumonia. Retrospective sequencing of the inoculum revealed a common in vitro adaptation in the furin cleavage site of the spike protein that may have reduced in vivo viral fitness. As such, we cannot exclude the possibility that use of an isolate with an intact furin cleavage motif would more efficiently infect bison.

IntroductionMycoplasma bovis causes chronic respiratory disease with high mortality rates in American bison (Bison bison). A recent study showed that a subunit vaccine containing M. bovis elongation factor thermal unstable (EFTu) and heat shock protein 70 (Hsp70) antigens induced immunity and enhanced protection in bison, resulting in reduced lung lesions and bacterial loads following experimental M. bovis challenge. This study aimed to characterize the transcriptional responses underlying this protection in vaccinated (n = 5) compared to unvaccinated control (n = 4) bison following M. bovis infection.MethodsTwo doses of vaccines were administered on day 0 and at 21 days post-vaccination (DPV), followed by intranasal inoculation with bovine herpesvirus-1 (BHV-1) at 36 DPV and M. bovis at 40 DPV. RNA sequencing was performed on liver, palatine tonsil (PT), retropharyngeal lymph node (RPLN), tracheobronchial lymph node (TBLN), spleen, and whole blood samples. Blood was collected at 1st vaccination (Day 0), 2nd vaccination (21 days post-vaccination), BHV-1 inoculation (36 DPV), M. bovis inoculation (40 DPV), and 1 week post M. bovis inoculation (47 DPV).Results and discussionThe greatest number of differentially expressed transcripts (DETs) (≤0.05 FDR) were found in blood at 36 DPV (123 total DETs) and in spleen (57 DETs). At 36 DPV, vaccinated animals showed upregulation of transcripts involved in in cell adhesion, T-helper cell (Th1/Th2/Th17) differentiation, and antigen processing and presentation. This signifies a robust response to the 2nd vaccine dose, which caused increased expression of CD3E, CD4, and CD8B correlating to increased T cell proliferation. Notably, transcription factors TBX21 and GATA3 were upregulated in vaccinated animals. Spleen-specific regulation included transcripts involved in innate immune response, such as LGALS3 and GBP-1. These findings highlight the robust immune response induced by the vaccine, particularly through T-cell mediated responses, demonstrating its potential to enhance protective immunity against M. bovis in bison.

Nemabiome metabarcoding of wild conservation bison herds and co-grazing cattle reveals different species compositions and low-level benzimidazole resistance

American plains bison (Bison bison bison, bison hereafter) experienced an extreme demographic bottleneck in the late 1800s. The species has since rebounded but is primarily managed as small and isolated herds due to habitat and sociopolitical limitations. Thus, reintroducing bison and allowing herds to achieve as much of their natural dynamics as possible is a major conservation goal. Concerns about genetic diversity loss in small, isolated herds and the persistence of cattle-origin variants from historical crossbreeding efforts have made genetic analysis an important part of bison conservation. The limitations of the current conservation genetic tools which are based on traditional markers such as microsatellites and mitochondrial DNA sequences, may be overcome with genome-wide genotyping panels commonly developed for agricultural species. Bison reintroduction in the grasslands at American Prairie began in 2005. Genetic analysis on these herds has yet to be conducted. We used the Illumina 777K Bovine genotyping panel to obtain data from 197 bison and 179 domestic cows to understand the current population genetic state of bison at American Prairie and gain insight on cattle (Bos taurus) introgression. Overall, bison at American Prairie currently have relatively high genetic diversity, low inbreeding, and no obvious signs of cattle introgression. A more comprehensive evaluation of introgression, likely including whole-genome sequence data, would clarify this finding. These results can serve as a baseline for future comparison as part of a genetic monitoring framework.

Comparative innate immune responses of bison and cattle to Mannheimia haemolytica wildtype and LPS sialylation-deficient mutant strains.

Abstract Quaking aspen (Populus tremuloides) and willows (Salix spp.) are keystone species of montane and shrub‐steppe landscapes of the Western United States. Intact communities dominated by these species provide a wide range of ecosystem services, harboring an exceptional proportion of landscape biodiversity. Land use, especially overgrazing by large ungulates, is among the greatest threats to these ecosystems. To examine the effects of wild ungulates and levels of grazing at Yellowstone National Park (YNP) and the adjacent Gallatin National Forest, we sampled plant community composition and vegetation structure of aspen and willow communities both inside and outside of exclosures. Within the Park, we found that current grazing pressures from large ungulates, principally American Bison (Bison bison), have a dramatic effect on community composition and structure, resulting in a shift from a structurally diverse forest or tall shrub dominance to that of a grassland. On heavily grazed sites, shrubs common to semiarid uplands are now relatively abundant, as are exotic grass species, in contrast to an abundance of berry‐producing shrubs within exclosures. Finally, large herbivores at unnaturally high densities are resulting in the simplification of landscape diversity outside of exclosures through a decline in the patch diversity of the site (i.e., homogenization of the landscape). Increases in exotic species and those adapted to semiarid environments suggest that current levels of bison use at YNP are amplifying the effects of climate change as well as resulting in a loss of biodiversity values. Inside exclosures, the inherent resilience of these keystone ecosystems was demonstrated by the recovery of plant diversity following decades of large ungulate utilization exceeding natural carrying capacity. This suggests that reductions in current grazing pressures within YNP would have positive feedbacks to beneficial ecosystem processes such as increased species and habitat diversity, increased carbon sequestration, and a greater adaptive capacity to climate change.

Subspecific variation in gut microbiota of North American bison in a sympatric setting reveals differentially abundant taxa.

Bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) are two viruses belonging to the genus Orbivirus that are transmitted via insect vector, the Culicoides biting midge, causing disease in domestic and wild ruminants. These infections can lead to significant morbidity, mortality, and production losses in livestock, with economic consequences for cattle and sheep industries. Despite their growing impact due to environmental and anthropogenic changes, little is known of the prevalence of these viruses in North American bison (Bison bison). We present the first cross-sectional survey of BTV and EHDV in North American bison, with samples collected from 287 animals across 9 herds in 7 U.S. states from September to November 2023. Using competitive enzyme-linked immunosorbent assays (cELISA), we detected seroprevalence rates of 56.5% for BTV and 57.5% for EHDV. We found higher seroprevalence in North American bison compared to reports in European bison populations, suggesting that bison could potentially serve as incidental hosts of orbiviruses during key transmission periods; however, their role in virus transmission remains uncertain and warrants further investigation, particularly regarding the duration of viremia, potential amplification capacity, and year-to-year variability in PCR positivity. Logistic regression analysis revealed age as a significant predictor for both BTV (OR: 1.15, CI: 1.05–1.26, p: 0.006) and EHDV (OR: 1.16, CI: 1.06–1.28, p: 0.0014) seropositivity. PCR amplification identified circulating BTV serotypes 6, 11, 13, 17. Additionally, age was negatively associated with PCR positivity for both BTV (OR: 0.70, CI: 0.53–0.93, p: 0.014) and EHDV (OR: 0.56, CI: 0.33–0.93, p: 0.024), suggesting a decline in detectable viremia with increasing age. Although complex environmental and epidemiological factors likely play a role, this trend may be due to older animals having experienced more vector seasons, thereby increasing their cumulative exposure and subsequent immunity to these viruses over time. The significant age-associated dynamics reveal the importance of considering life stage in disease surveillance and management. Our study also highlights the importance of integrating bison into future vector-borne disease research and control strategies to mitigate risks to livestock, wildlife, and ecosystem health.

ABSTRACT In 2016, the American Bison Coalition (ABC)—an alliance of conservationists, ranchers, Indigenous advocates, and others—petitioned the U.S. government to designate the American bison as the national mammal. They aimed to create a patriotic conservation symbol to rally cross-sector stakeholder support for the Bison Restoration Movement. Scholars have criticized such symbolism for provoking conflict due to its reliance on synecdochic argumentation. Using the Vote Bison Campaign as an illustrative case study, this article argues that synecdoche can also foster cohesion. A rhetorical analysis of the ABC's official statements shows how ironic synecdochic appeals framed the bison as an open-ended, inclusive symbol. This rhetorical strategy affirmed the coalition's diverse and sometimes oppositional priorities, cultivating a discursive atmosphere that enabled alignment without consensus.

A modified-live Mannheimia haemolytica expressing Mycoplasma bovis EFTu and Hsp70 induced systemic and mucosal antibody responses in American bison but failed to fully protect against Mycoplasma bovis challenge.