Application of bovine microsatellite markers for genetic diversity analysis of European bison (Bison bonasus)

In this study, the cross‐amplification of a commercial multiplex set of 11 cattle (Bos taurus) microsatellites was tested on a panel of 35 European bison (Bison bonasus) individuals. After polymerase chain reaction optimization, all loci cross‐amplified successfully in investigated bisons. Number of alleles and observed and expected heterozygosity per locus are in the range of 2–4, 0.086–0.629 and 0.288–0.621 respectively. The availability of a heterologous set of multiplexed microsatellite markers derived from cattle opens an avenue for collecting profound genetic data for efficient conservation management strategies of the European bison.     

Pathological lesions in European bison (Bison bonasus) with infestation by Ashworthius sidemi (Nematoda, Trichostrongylidae)

Asworthius sidemi Schulz, 1933 is a blood sucking gastrointestinal nematode, primarily typical for Asiatic deer. It was found for the first time in Poland in European bison in 1997. To estimate the level of invasion of A. sidemi and histopathological changes connected with the presence of the parasite in the years 2004-2007 parasitological and histopathological examinations of 54 European bison from Bia?owieza Forest were carried out. Parasitological examination was carried out by the sedimentation method and A. sidemi were diagnosed under a binocular microscope. Samples for histological examination were collected from the abomasum and duodenum walls as well as from regional lymph nodes. Tissue samples were then fixed with 10% buffered formalin, embedded in paraffin, cut in to 5 microm thick sections and stained with hematoxylin and eosin (H&E). Parasitological examinations showed the presence of fourth stage larvae and juvenile forms of A. sidemi. The maximal intensity of invasion rose systematically from 4470 A. sidemi nematodes in 2004/2005 to 44310 in 2006/2007. Histopathological examinations showed infiltrations of inflammatory cells in the walls of abomasa and duodena at various levels of intensity (mainly lymphoid cells and eosinophils), hyperemiae, oedemae and lesions of mucosa and proliferation of lymphatic follicles. In individual cases of dysplasia of epithelial cells, atrophy or hyperplasia of glands and the presence of parasites in the lumen or walls of the abomasum/duodenum were observed. In one case, parasitic nodules were found. In regional lymph nodes proliferation of lymphatic follicles, presence of eosinophils and desolation of reproduction centers were observed. Intensification of histopathological changes was connected to a considerable degree with the developmental stage of A. sidemi as shown by parasitological examination.     

Antibodies to Neospora caninum in the blood of European bison (Bison bonasus bonasus L.) living in Poland

The prevalence of antibodies to Neospora caninum was examined in European bison (Bison bonasus bonasus L.) living in free and fenced areas in Poland. Sera of 320 European bison, different ages and sexes, from breeding areas in Poland were tested for N. caninum antibodies using ELISA test. Positive antibody responses were found in 23 bison (prevalence 7.3%). Additionally, all positive sera were tested by Western blot to verify the ELISA results. The Western blot results confirmed the presence of antibodies to Neospora tachyzoites antigens in all 23 sera tested. The antibodies were detected against a wide range of NC-1 tachyzoite antigens. The antibody responses were directed against proteins at: 9.5, 17, 21, 27, 31, 36.5, 38, 40, 43, 47, 48.5, 53.5 and 58 kDa. The most heavily stained bands had molecular weights of 9.5, 17, 27 and 58 kDa. The most important is that antibody to N. caninum was detected for the first time in sera from bison cow shot in 1988. It is the year of recognition of this protozoan parasite. Our results indicate strongly the presence of N. caninum in European bison in Poland and suggest that a sylvatic cycle of N. caninum can exist. However, further studies are needed to evaluate the existence of a sylvatic cycle of N. caninum. The study on the effect of the infection on the health status and conservation of European bison should be taken under consideration too.     

Phenotypic characteristics and virulence genotypes of Trueperella (Arcanobacterium) pyogenes strains isolated from European bison (Bison bonasus)

In a breeding and fattening pig farm an increasing number of cases of abortion and generalized mycobacteriosis at slaughter occurred. Pathological findings compatible with mycobacteriosis, acid-fast organisms in tissues, and isolation of mycobacteria from tissue samples including fetuses, lungs and reproductive organs from sows, genital swabs, mesenteric lymph nodes, and from a sperm sample revealed the cause of the disease. Bacterial cultures were identified as Mycobacterium avium subsp. hominissuis using IS901-/IS1245-specific PCR. Genotyping of selected isolates from animals as well as from their environment by MIRU-VNTR analysis showed that the herd was infected with one single outbreak strain. The same genotype was also isolated from pigs of two other farms which showed comparable symptoms and were in direct contact with the index farm as well as from their environment. Immunological host responses detected by tuberculin skin test and ELISA gave positive results at herd level only. Despite the detection of other potential pathogens mycobacteria were regarded as the causative agent of the reproductive disorders. To our knowledge this is the first report of an epidemic mycobacterial infection in a pig holding associated with reproductive disorders, which could be attributed to one single virulent strain, and the first report of detection of M. avium subsp. hominissuis in pig sperm.     

Immunoexpression of Aromatase in Immature and Adult Males of the European Bison (Bison bonasus,Linnaeus 1758)

Based on recent literature dealing with the role of oestrogens in the male gonad, attempts were undertaken to reveal the site of aromatization within the testis of the European bison (Bison bonasus). Testes were collected from culled animals living in free‐ranging populations in Bialowieza Forest, Poland (nine males aged 8 months to 10 years). Moreover, to check for any alterations in the expression of testicular aromatase between American bison (Bison bison) and European bison, testes from one adult 10‐year‐old individual were also chosen for this study. For immunohistochemistry, 4% formaldehyde fixative was used. Both qualitative and quantitative evaluations of immunohistochemical staining were performed. Leydig cells, Sertoli cells and germ cells exhibited a positive immunoreaction for aromatase in testes of immature and sexually mature bison. A marked increase in aromatase expression was observed in three adult European individuals with impaired spermatogenesis. Consistent with recent data and those of our own, it might be suggested that the strong expression of aromatase negatively affects spermatogenic function in bison testes and may serve as a possible explanation of specific sperm defects observed in European bison bulls. On the contrary, one cannot exclude that differences in the aromatase immunoexpression levels are attributed to the homozygosity, the cause of frequent disease in European bison.     

Recovery and Cryopreservation of Epididymal Sperm of Plains Bison (Bison bison bison) as a Model for Salvaging the Genetics of Wood Bison (Bison bison athabascae)

The objective of this study was to optimize recovery and cryopreservation of epididymal sperm from plains bison, as a model for wood bison. In Phase 1, cauda epididymides were recovered from bison (n = 14) immediately after slaughter, minced and incubated in Sp-TALPH buffer for 3 h at 36°C. The resulting sperm suspensions were cryopreserved in Triladyl^®, using a protocol for bovine semen. In Phase 2, epididymal sperm were cryopreserved in either Triladyl^® or Andromed^®. The mean (±SD) estimated number of sperm recovered was 468 ± 207 × 10⁶. There was an increase (p < 0.05) in the proportion of sperm with normal morphology between initial recovery and after extension (52.4 ± 4.6 vs 69.7 ± 2.4%), with a concurrent decrease (p < 0.05) in the proportion of sperm with distal droplets. Median values for progressively motile sperm in post-thaw samples (60%) were lower (p < 0.05) than that after extension or after chilling (70% for both). The mean percentages of viable sperm and of sperm with an intact acrosome were lower (p < 0.05) for frozen-thawed samples (38.7 ± 2.8 and 85.2 ± 1.1) compared with extended (66.2 ± 2.2 and 92.4 ± 0.9) or chilled (63.7 ± 2.5 and 90.0 ± 1.0) samples. Rates of cleavage, morulae and blastocyst production were not significantly different for chilled (70.9, 38.7 and 8.0%) vs post-thaw sperm (73.0, 46.0 and 6.3%). There was no significant difference between extenders for most sperm characteristics. In conclusion, we developed a functional protocol for the recovery and cryopreservation of epididymal sperm from plains bison, which may have implications for the genetic preservation of wood bison.     

Squamous cell carcinoma in an American bison (Bison bison bison)

The following case report is, to the best of our knowledge, the first documentation of a squamous cell carcinoma in a full-blooded American bison (Bison bison bison). This female bison developed an ulcerated lesion on the left flank, at the site of a brand, in the summer of her eighth year. In the winter of her ninth year, as the lesion continued to grow, a biopsy was performed, and a diagnosis of squamous cell carcinoma was made. Ultimately, there was metastasis to the liver, a lung, and a prefemoral lymph node.     

Malignant schwannoma in an American buffalo (Bison bison bison)

A case of a malignant schwannoma in a 20-year-old male American buffalo (Bison bison bison) from the Grand Park Zoo, Gyeonggi Province, Republic of Korea is reported. The animal showed no apparent clinical signs before death except for wound on the neck. Grossly, neoplastic nodules of various sizes were observed on the skin, lung, heart, liver, stomach, mesentery and kidney. Histologically, the neoplastic nodules were composed of fusiform cells that formed multidirectional bundles. The tumour cells were arranged in interlacing bands and bundles. The nuclei were atypical, hyperchromatic, with blunt or round ends. In addition, few mitotic figures were observed in the skin, lung, heart, liver, stomach, intestine and kidney. Several immunohistochemical stains, e.g. vimentin, cytokeratin (CK), smooth muscle actin (SMA), S-100 and HMB45, were used in an attempt to differentially diagnose the tumour. The neoplastic cells tested positive to S-100, but negative to vimentin, CK, SMA and HMB45. Based on the above findings, this case was diagnosed as a malignant schwannoma. To the best of our knowledge, this is the first report of a schwannoma in an American buffalo (B. b. bison).     

The efficacy of pour-on ivermectin in bison (Bison bison)

To test the effectiveness of pour-on ivermectin in parasitized bison, changes in fecal parasite egg counts after treatment with ivermectin injectable or pour-on preparations were compared to a negative control group. There was no difference between the two ivermectin groups, and both forms of ivermectin were effective in reducing fecal parasite egg counts in parasitized bison.     

Effect of Reproductive Seasonality on Gamete Quality in the North American Bison (Bison bison bison)

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.     

Comparative blood characteristics of ranched and free-ranging American bison (Bison bison)

Blood samples were obtained from 20 bison (Bison bison) from a ranch in northern lower Michigan, as well as from 20 free-ranging bison of the same sex and similar age from the Badlands National Park in South Dakota. Hematologic and serum biochemical values were determined. The values were comparable in both groups, except for those for BUN, aspartate transaminase, and phosphorus, which were significantly (P less than 0.001) higher in the ranched bison than in the free-ranging bison. These differences were attributed to nutritional effects. Impact of age on blood characteristics was assessed in the ranched bison only by comparing values from calves weighing less than 185 kg with those from bison weighing more than 185 kg. Calves had significantly (P less than 0.001) higher values for phosphorus and RBC counts and lower total protein values than adults. Adult bison had higher eosinophil and neutrophil counts with lower numbers of lymphocytes, suggestive of a stress leukogram, whereas calves had the typical bovine neutrophil:lymphocyte ratio.     

Clinical Parelaphostrongylus tenuis infection in two captive American bison (Bison bison)

CASE DESCRIPTION: 2 juvenile (17 and 19 months of age) male American bison (Bison bison) were examined because of acute bilateral hind limb weakness and ataxia; 1 animal also had urinary incontinence. TREATMENT AND OUTCOME: Given the clinical signs and rapid deterioration in the condition of these 2 animals, obtaining a definitive diagnosis was considered essential to minimizing the risk of disease in the remaining bison herd and among other animals at the facility. Therefore, both affected animals were euthanized. At necropsy, no gross abnormalities were seen. Histologic examination of sections of the brains from both animals revealed mild to moderate multifocal aggregates of eosinophils and mononuclear cells in perivascular regions of the meninges and gray matter of the cerebrum, cerebellum, and brainstem. Systematic examination of multiple sections of brain and spinal cord revealed evidence of nematode sections and aberrant parasite migration. CLINICAL RELEVANCE: Findings suggested that CNS migration of Parelaphostrongylus tenuis in American bison may cause clinical signs. These findings have implications for the management of captive bison and free-ranging bison sharing ranges with white-tailed deer (Odocoileus virginianus), the definitive host, and elk (Cervus elaphus canadensis).     

Spinal intradural Mycobacterium haemophilum granuloma in an American Bison (Bison bison)

Mycobacterium haemophilum, a nontuberculous mycobacterium, is a pathogen in immunocompromised human patients. We report a case of M haemophilum-induced granuloma in the spinal cord of an American Bison (Bison bison). M haemophilum infection was diagnosed by sequencing a portion of the 16 S ribosomal DNA and comparing the amplicon sequence with sequences in GenBank.     

The pathology of spontaneous paratuberculosis in the North American bison (Bison bison)

Gross and histopathologic examinations were performed on 70 North American bison (Bison bison) from a Mycobacterium avium paratuberculosis culture-positive herd. The bison examined were part of a breeding herd totaling 2,800 animals. Eight of 70 (11%) animals had gross findings of intestinal mucosal thickening, and 16 of 70 (23%) of the animals had enlarged mesenteric lymph nodes. Histologic lesions compatible with Johne's disease were diagnosed in 30 of 70 (43%) bison on the basis of the demonstration of noncaseating granulomatous inflammatory infiltrates and of one or more acid-fast bacilli characteristic of Mycobacterium avium paratuberculosis. A suspicious diagnosis of Johne's disease was obtained in 11 of 70 (16%) bison on the basis of the observation of noncaseating granulomatous inflammatory infiltrates without demonstrable acid-fast bacteria. Twenty-nine of 70 (41%) animals were assessed as histologically paratuberculosis free. Histologic results were compared to Johne's disease tests such as culture, serology, and polymerase chain reaction, which were performed on some of the cohort animals.     

Toxocara vitulorum in a bison (Bison bison) herd from western Canada

The discovery of the parasite Toxocara vitulorum in bison calves in the province of Manitoba, Canada is discussed. This parasite is more commonly found in the small intestines of bovid calves living in tropical and subtropical regions of the world. This is the first time that Toxocara vitulorum has been reported from hosts in Canada.     

Malignant catarrhal fever in a bison (Bison bison) feedlot, 1993-2000.

A fatal enteric syndrome was identified in American bison (Bison bison) at a large feedlot in the American Midwest in early 1998. An estimated 150 bison died of the syndrome between January 1998 and December 1999. The syndrome was identified as malignant catarrhal fever (MCF), primarily the alimentary form. Clinical onset was acute, and most affected bison died within 1-3 days; none recovered. Consistent lesions were hemorrhagic cystitis, ulcerative enterotyphlocolitis, and arteritis-phlebitis. Vasculitis was milder and more localized than that in cattle with MCF, and in contrast to the situation in cattle, lymphadenomegaly was minimal. Virtually all affected bison examined were positive for ovine herpesvirus 2 (OvHV-2) by polymerase chain reaction (PCR) assay. A retrospective study of archived tissues established that MCF occurred in the yard as early as 1993. A prospective study was undertaken to establish the importance of MCF relative to other fatal diseases at the feedlot. The fate of a group of 300 healthy male bison in a consignment of 1,101 animals was followed for up to 7 months to slaughter. At entry, 23% (71/300) of bison were seropositive for MCF viruses, and 11% (8/71) of these seropositive bison were PCR positive for OvHV-2. Forty seronegative bison were selected at random from the group, and all were PCR negative for OvHV-2. There was no change in seroprevalence in the group during the investigation. The minimum infection rate for MCF virus was 36.3% (93/256). Twenty-two (7.3%) of the 300 bison in the feedlot died. Of these, 15 had MCF, 4 had acute or chronic pneumonia, and 3 were unexamined. Losses in the entire consignment were higher (98/1,101; 8.8% death loss); 76% of deaths were attributable to MCF. The study failed to reveal a relationship between subclinical infection and development of clinical disease.