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Concept: American Bison


In the US Corn Belt, a recent doubling in commodity prices has created incentives for landowners to convert grassland to corn and soybean cropping. Here, we use land cover data from the National Agricultural Statistics Service Cropland Data Layer to assess grassland conversion from 2006 to 2011 in the Western Corn Belt (WCB): five states including North Dakota, South Dakota, Nebraska, Minnesota, and Iowa. Our analysis identifies areas with elevated rates of grass-to-corn/soy conversion (1.0-5.4% annually). Across the WCB, we found a net decline in grass-dominated land cover totaling nearly 530,000 ha. With respect to agronomic attributes of lands undergoing grassland conversion, corn/soy production is expanding onto marginal lands characterized by high erosion risk and vulnerability to drought. Grassland conversion is also concentrated in close proximity to wetlands, posing a threat to waterfowl breeding in the Prairie Pothole Region. Longer-term land cover trends from North Dakota and Iowa indicate that recent grassland conversion represents a persistent shift in land use rather than short-term variability in crop rotation patterns. Our results show that the WCB is rapidly moving down a pathway of increased corn and soybean cultivation. As a result, the window of opportunity for realizing the benefits of a biofuel industry based on perennial bioenergy crops, rather than corn ethanol and soy biodiesel, may be closing in the WCB.

Concepts: Agriculture, Native Americans in the United States, Biofuel, Ethanol fuel, Minnesota, American Bison, South Dakota, National Agricultural Statistics Service


Since 1980, bison have injured more pedestrian visitors to Yellowstone National Park (Yellowstone) than any other animal (1). After the occurrence of 33 bison-related injuries during 1983-1985 (range = 10-13/year), the park implemented successful outreach campaigns (1) to reduce the average number of injuries to 0.8/year (range = 0-2/year) during 2010-2014 (unpublished data, National Park Service, September 2015). During May-July 2015, five injuries associated with bison encounters occurred (Table). Case reports were reviewed to evaluate circumstances surrounding these injuries to inform prevention.

Concepts: United States, American Bison, Yellowstone National Park, National Park Service, National park, Fort Yellowstone, Mission 66, Harry Yount


Hybridization between endangered species and more common species is a significant problem in conservation biology because it may result in extinction or loss of adaptation. The historical reduction in abundance and geographic distribution of the American plains bison (Bison bison bison) and their recovery over the last 125 years is well documented. However, introgression from domestic cattle (Bos taurus) into the few remaining bison populations that existed in the late 1800s has now been identified in many modern bison herds. We examined the phenotypic effect of this ancestry by comparing weight and height of bison with cattle or bison mitochondrial DNA (mtDNA) from Santa Catalina Island, California (U.S.A.), a nutritionally stressful environment for bison, and of a group of age-matched feedlot bison males in Montana, a nutritionally rich environment. The environmental and nutritional differences between these 2 bison populations were very different and demonstrated the phenotypic effect of domestic cattle mtDNA in bison over a broad range of conditions. For example, the average weight of feedlot males that were 2 years of age was 2.54 times greater than that of males from Santa Catalina Island. In both environments, bison with cattle mtDNA had lower weight compared with bison with bison mtDNA, and on Santa Catalina Island, the height of bison with cattle mtDNA was lower than the height of bison with bison mtDNA. These data support the hypothesis that body size is smaller and height is lower in bison with domestic cattle mtDNA and that genomic integrity is important for the conservation of the American plains bison. Efectos Fenotípicos del ADN Mitocondrial de Ganado en el Bisonte Americano.

Concepts: Cattle, Beef, Extinction, American Bison, Bison, Bovinae, Bos, Gaur


The objectives of this study were to determine the feasibility of daily examination of wild-caught wood bison and to characterize the ovarian function using serial transrectal ultrasonography and blood hormone analysis. Ten 2-year-old wood bison heifers obtained from Elk Island National Park were placed in a corral adjacent to a handling system designed for restraining bison. The handling system was left open to the corral allowing the bison to explore it freely for 2 months. Active acclimation followed for a 2-week period, during which the bison were herded daily through the handling system and rewarded with whole oats. Finally, the bison were restrained in the handling system and rewarded with whole oats upon release. Once conditioned, daily transrectal examination of the ovaries was completed in 100% of attempts for 30 days (January-February) using a B-mode scanner with a 5 to 10-MHz linear array. Follicle size and numbers were recorded, and individual follicles were identified serially. Blood samples were collected daily and the serum was analyzed for FSH concentrations. Nonrandom changes were detected in the number of follicles ≥4 mm in diameter per day (P < 0.05). Each peak in follicle numbers was associated with the development of a single dominant follicle. The interval between the emergence of successive dominant follicles was 6.8 ± 0.6 days (mean ± SEM). The maximum diameter of the dominant follicle was 9.9 ± 0.4 mm. In conclusion, wild-caught wood bison were amenable to daily examination and blood sampling, and ovarian dynamics were characterized by wave-like development of anovulatory antral follicles. The demonstrated success of this approach to the study of ovarian function will be useful for characterizing the annual reproductive pattern in wood bison, which is necessary for the development of bison-specific protocols for controlling ovarian function for species conservation.

Concepts: Menopause, Ovarian follicle, Puberty, American Bison, Bison, Follicular phase, Wood Bison, Mammals of Canada


Tulathromycin is approved for the treatment of respiratory disease in cattle and swine. It is intended for long-acting, single-dose injection therapy (Draxxin), making it particularly desirable for use in bison due to the difficulty in handling and ease of creating stress in these animals. The pharmacokinetic properties of tulathromycin in bison were investigated. Ten wood bison received a single 2.5 mg/kg subcutaneous injection of Draxxin. Serum concentrations were measured by liquid chromatography-mass spectrometry (LC-MS) detection. Tulathromycin demonstrated early maximal serum concentrations, extensive distribution, and slow elimination characteristics. The mean maximum serum concentration (Cmax ) was 195 ng/mL at 1.04 h (tmax ) postinjection. The mean area under the serum concentration-time curve, extrapolated to infinity (AUC0-inf ), was 9341 ng·h/mL. The mean apparent volume of distribution (Vd /F) and clearance (Cls/F) was 111 L/kg and 0.4 L/h/kg, respectively, and the mean half-life (t1/2 ) was 214 h (8.9 days). Compared to values for cattle, Cmax and AUC0-inf were lower in bison, while the Vd /F was larger and the t1/2 longer. Tissue distribution and clinical efficacy studies in bison are needed to confirm the purported extensive distribution of tulathromycin into lung tissue and to determine whether a 2.5 mg/kg subcutaneous dosage is adequate for bison.

Concepts: Pharmacology, Distribution, Pharmacokinetics, American Bison, Bison, Bovinae, Wood Bison, Wisent


The objective was to investigate the effects of reproductive seasonality on gamete quality in plains bison (Bison bison bison). Epididymal sperm (n = 61 per season), collected during the breeding season (July-September), had significantly higher post-thaw total motility (36.76 ± 14.18 vs 31.24 ± 12.74%), and lower linearity (0.36 ± 0.06 vs 0.39 ± 0.04) and wobbliness (0.49 ± 0.04 vs 0.51 ± 0.03; mean ± SD) compared to non-breeding season (January-March) samples. Representative samples (n = 4) from each season were used in heterologous IVF trials using cattle oocytes. Cleavage, morulae and blastocyst percentage were higher for breeding vs non-breeding season sperm samples (81.88 ± 6.8 vs 49.94 ± 6.77; 41.89 ± 13.40 vs 27.08 ± 23.21; and 30.49 ± 17.87 vs 13.72 ± 18.98%, respectively). Plains bison ovaries collected during the breeding (n = 97 pairs) and non-breeding (n = 100 pairs) seasons were classified as luteal or follicular. Oocytes recovered from these ovaries were classified into five grades based on morphology. There was no significant difference in the number of luteal ovaries or grades of oocytes recovered. Oocytes were matured, fertilized (with frozen sperm from three bison bulls) and cultured in vitro. Cleavage percentage was higher for oocytes collected during breeding vs non-breeding season (83.72 ± 6.42 vs 73.98 ± 6.43), with no significant difference in subsequent development to blastocysts. In summary, epididymal sperm from non-breeding season had decreased total motility and resulted in reduced embryo production in vitro. Oocytes collected during non-breeding season had reduced ability to be matured, fertilized and/or undergo cleavage in vitro. Data suggested that season influenced gamete quality in plains bison.

Concepts: Reproduction, In vitro fertilisation, Zygote, American Bison, Bison, Megafauna of North America, Wisent, Plains Indians


Endemic brucellosis threatens wild herds of wood bison (Bison bison athabascae) in and around Wood Buffalo National Park, the largest genetic reserve of wood bison in the world. The overall goal of our project was to produce and preserve disease-free embryos for the purpose of conserving the genetic diversity of this species. The aim of the present experiment was to determine the effectiveness of washing procedures for removing Brucella bacteria from in vivo-derived wood bison embryos exposed in vitro to the pathogen. Wood bison cows were given 300mg im of Folltropin diluted in 0.5% hyaluronan on the day of follicle wave emergence (Day 0) and 100mg im of hyaluronan on Day 2, and then given 2500IU im of hCG on Day 5 and inseminated 12 and 24h later. Embryos were collected on Day 13. The experiment was done in 6 replicates (n=4 bison/replicate) and an average of 9 embryos/replicate were collected. Zona pellucida-intact embryos were kept in holding medium (PBS+2% fetal calf serum) and transported to a Biosafety Level 3 laboratory at the International Vaccine Centre, University of Saskatchewan. Embryos were transferred through 5 aliquots of holding medium to remove any contaminant before exposure to Brucella. Embryos were divided equally into 2 Petri dishes (representing later wash groups with v. without antibiotics) containing 2.7mL of holding medium (n=2 to 7 embryos per dish/replicate). In a Class II biosafety cabinet, Brucella abortus biovar 1 (1×10(7) to 1×10(9)CFUmL(-1) in 0.3mL) was added to each Petri dish and incubated for 2h at 37°C in 8% CO2. A sample of holding medium was taken before exposure and after incubation for culture as negative and positive controls, respectively. After incubation, embryos in each Petri dish were subjected to a 10-step washing procedure (according to the IETS Manual, 2010) using wash medium (PBS+0.4% BSA) without antibiotics or with antibiotics (100IUmL(-1) of penicillin+100μgmL(-1) of streptomycin). The embryo wash medium was cultured at wash steps 1, 3, 6, and 9. After the tenth wash, the zona pellucida of each embryo was ruptured mechanically using a glass pipette and embryos were cultured individually. Culturing of samples was done on sheep blood agar and specific identification of Brucella organisms was done by PCR. Brucella abortus was detected in 3 embryos from the group washed in medium without antibiotics (3/27), whereas all embryos washed in medium with antibiotics were culture negative (0/27). Brucella abortus was not detected in wash media after the third wash in either group (with or without antibiotics). In summary, Brucella abortus was removed from 89% of in vitro-exposed wood bison embryos using the washing procedure without antibiotics, and from 100% using the washing procedure with antibiotics. Results validate the embryo washing technique for producing Brucella-free wood bison embryos.

Concepts: Fetus, Brucellosis, Agar, Agar plate, American Bison, Bison, Petri dish, Wood Bison


North American bison (Bison bison) are becoming increasingly important to both grassland management and commercial ranching. However, a lack of quantitative data on their diet constrains conservation efforts and the ability to predict bison effects on grasslands. In particular, we know little about the seasonality of the bison diet, the degree to which bison supplement their diet with eudicots, and how changes in diet influence gut microbial communities, all of which play important roles in ungulate performance. To address these knowledge gaps, we quantified seasonal patterns in bison diet and gut microbial community composition for a bison herd in Kansas using DNA sequencing-based analyses of both chloroplast and microbial DNA contained in fecal matter. Across the 11 sampling dates that spanned 166 days, we found that diet shifted continuously over the growing season, allowing bison to take advantage of the seasonal availability of high-protein plant species. Bison consumed more woody shrubs in spring and fall than in summer, when forb and grass intake predominated. In examining gut microbiota, the bacterial phylum Tenericutes shifted significantly in relative abundance over the growing season. This work suggests that North American bison can continuously adjust their diet with a high reliance on non-grasses throughout the year. In addition, we find evidence for seasonal patterns in gut community composition that are likely driven by the observed dietary changes.

Concepts: Bacteria, Gut flora, Microbiology, Grassland, American Bison, Bison, Wood Bison, Wisent


Wild American plains bison (Bison bison) populations virtually disappeared in the late 1800s, with some remnant animals retained in what would become Yellowstone National Park and on private ranches. Some of these private bison were intentionally crossbred with cattle for commercial purposes. This forced hybridization resulted in both mitochondrial and nuclear introgression of cattle genes into some of the extant bison genome. As the private populations grew, excess animals, along with their history of cattle genetics, provided founders for newly established public bison populations. Of the US public bison herds, only those in Yellowstone and Wind Cave National Parks (YNP and WCNP) appear to be free of detectable levels of cattle introgression. However, a small free-ranging population (~350 animals) exists on public land, along with domestic cattle, in the Henry Mountains (HM) of southern Utah. This isolated bison herd originated from a founder group translocated from YNP in the 1940s. Using genetic samples from 129 individuals, we examined the genetic status of the HM population and found no evidence of mitochondrial or nuclear introgression of cattle genes. This new information confirms it is highly unlikely for free-living bison to crossbreed with cattle, and this disease-free HM bison herd is valuable for the long-term conservation of the species. This bison herd is a subpopulation of the YNP/WCNP/HM metapopulation, within which it can contribute significantly to national efforts to restore the American plains bison to more of its native range.

Concepts: Genetics, United States, American Bison, Bison, Yellowstone National Park, Wyoming, Wind Cave National Park, Henry Mountains


Despite the abundance of fossil remains for the extinct steppe bison (Bison priscus), an animal that was painted and engraved in numerous European Paleolithic caves, a complete mitochondrial genome sequence has never been obtained for this species. In the present study we collected bone samples from a sector of the Trois-Frères Paleolithic cave (Ariège, France) that formerly functioned as a pitfall and was sealed before the end of the Pleistocene. Screening the DNA content of the samples collected from the ground surface revealed their contamination by Bos DNA. However, a 19,000-year-old rib collected on a rock apart the pathway delineated for modern visitors was devoid of such contaminants and reproducibly yielded Bison priscus DNA. High-throughput shotgun sequencing combined with conventional PCR analysis of the rib DNA extract enabled to reconstruct a complete mitochondrial genome sequence of 16,318 bp for the extinct steppe bison with a 10.4-fold coverage. Phylogenetic analyses robustly established the position of the Bison priscus mitochondrial genome as basal to the clade delineated by the genomes of the modern American Bison bison. The extinct steppe bison sequence, which exhibits 93 specific polymorphisms as compared to the published Bison bison mitochondrial genomes, provides an additional resource for the study of Bovinae specimens. Moreover this study of ancient DNA delineates a new research pathway for the analysis of the Magdalenian Trois-Frères cave.

Concepts: DNA, Gene, Human Genome Project, Genome, American Bison, Bison, Bovinae, Wisent