Occurrence and diurnal population fluctuations of the ruminal protozoan Microcetus lappus

A series of experiments with bison and cattle were conducted to obtain information on the relatively uncommon ruminal protozoan Microcetus lappus. Although M. lappus is a holotrich, diurnal changes in concentrations indicate that it follows a cycle unlike most other holotrichs, decreasing shortly after feed is offered and then gradually increasing over time. Concentrations of M. lappus varied widely among animals, exceeding 50% of the total protozoan population in some cattle. In bison, Microcetus concentrations averaged 2% of the protozoan population. Dietary protein and energy levels apparently did not influence Microcetus numbers. The highest concentrations of M. lappus were found in the reticulum, whereas the lowest numbers occurred in the mid-dorsal sac.     

Ruminal ciliated protozoa in bison.

Ruminal contents from 79 slaughtered bison and 2 ruminally cannulated bison were collected to obtain information on total numbers and species distribution of ciliated protozoa. The bison originated from numerous herds throughout the Great Plains and were grouped into three dietary categories: (i) only forage; (ii) forage with moderate levels of supplementation; and (iii) feedlot concentrate-silage diet. Total ciliate counts were highest in bison receiving grain supplementation (210.1 x 10(4)/g) and lowest in bison consuming only forage (27.1 x 10(4)/g). All protozoan species found in bison have been reported in domestic livestock, although Ophryoscolex sp., a relatively common protozoan in cattle, was detected at low concentrations in only eight bison. The uncommon holotrich Microcetus lappus was present in five bison in concentrations reaching 8.4% of the total ciliate population. Charonina ventriculi, another infrequently observed species, was present in 18 bison, with the highest concentrations in forage-fed animals. Thirty bison possessed a type B protozoan population, characterized by Epidinium sp., Eudiplodinium maggii, and Eudiplodinium bovis. Thirty-eight bison possessed a mixed A-B population, characterized by Polyplastron sp. coexisting with low numbers of Eudiplodinium maggii or Epidinium sp. or both. Thirteen bison possessed populations lacking any remnant type B ciliate species. At least 29 of the bison possessing Polyplastron sp. were known to have been in contact with cattle, whereas all bison isolated from cattle had type B populations. The reduction of type B populations in bison becomes increasingly likely as bison production expands into areas inhabited by domestic livestock.     

Ruminal ciliated protozoa in bison

Ruminal contents from 79 slaughtered bison and 2 ruminally cannulated bison were collected to obtain information on total numbers and species distribution of ciliated protozoa. The bison originated from numerous herds throughout the Great Plains and were grouped into three dietary categories: (i) only forage; (ii) forage with moderate levels of supplementation; and (iii) feedlot concentrate-silage diet. Total ciliate counts were highest in bison receiving grain supplementation (210.1 x 10(4)/g) and lowest in bison consuming only forage (27.1 x 10(4)/g). All protozoan species found in bison have been reported in domestic livestock, although Ophryoscolex sp., a relatively common protozoan in cattle, was detected at low concentrations in only eight bison. The uncommon holotrich Microcetus lappus was present in five bison in concentrations reaching 8.4% of the total ciliate population. Charonina ventriculi, another infrequently observed species, was present in 18 bison, with the highest concentrations in forage-fed animals. Thirty bison possessed a type B protozoan population, characterized by Epidinium sp., Eudiplodinium maggii, and Eudiplodinium bovis. Thirty-eight bison possessed a mixed A-B population, characterized by Polyplastron sp. coexisting with low numbers of Eudiplodinium maggii or Epidinium sp. or both. Thirteen bison possessed populations lacking any remnant type B ciliate species. At least 29 of the bison possessing Polyplastron sp. were known to have been in contact with cattle, whereas all bison isolated from cattle had type B populations. The reduction of type B populations in bison becomes increasingly likely as bison production expands into areas inhabited by domestic livestock.     

Microcetus lappus gen. nov., sp. nov.: new species of ciliated protozoon from the bovine rumen

A new species of small, ciliated protozoon, Microcetus lappus gen. nov., sp. nov., from the rumen of Norwegian Red cattle is described. M. lappus possesses a novel cytopharyngeal apparatus of two rod-shaped structures, one situated on the dorsal side of the buccal cavity and one on the ventral side, suggesting that it belongs to a previously undescribed taxon.     

Microcetus lappus gen. nov., sp. nov.: new species of ciliated protozoon from the bovine rumen.

A new species of small, ciliated protozoon, Microcetus lappus gen. nov., sp. nov., from the rumen of Norwegian Red cattle is described. M. lappus possesses a novel cytopharyngeal apparatus of two rod-shaped structures, one situated on the dorsal side of the buccal cavity and one on the ventral side, suggesting that it belongs to a previously undescribed taxon.     

Omasal ciliated protozoa in cattle, bison, and sheep.

Omasal contents were collected from slaughtered cattle (n = 54), bison (n = 15), and sheep (n = 40) to determine numbers and generic distribution of ciliated protozoa. Total protozoan numbers were significantly lower in omasal contents than in ruminal contents of all three species, but the percent composition of all protozoan genera was similar between omasal and ruminal populations. The highest numbers of omasal protozoa found were 7.61 X 10(5)/g in cattle, 7.01 X 10(5)/g in bison, and 1.29 X 10(6)/g in sheep. Omasal dry matter was significantly higher than ruminal dry matter in all species and ranged up to 51.5% in cattle fed high-concentrate diets. The omasal pH was similar to the ruminal pH in all species. The number of omasal laminae averaged 149, 145, and 74 for cattle, bison, and sheep, respectively. Although protozoan concentrations in omasal contents were approximately 80% lower than those in ruminal contents, the omasum harbored relatively high numbers of ciliated protozoa. The resident omasal protozoa are extremely difficult to remove, particularly in cattle, and apparently are responsible for reinoculating transiently defaunated rumens.     

Omasal ciliated protozoa in cattle, bison, and sheep

Omasal contents were collected from slaughtered cattle (n = 54), bison (n = 15), and sheep (n = 40) to determine numbers and generic distribution of ciliated protozoa. Total protozoan numbers were significantly lower in omasal contents than in ruminal contents of all three species, but the percent composition of all protozoan genera was similar between omasal and ruminal populations. The highest numbers of omasal protozoa found were 7.61 X 10(5)/g in cattle, 7.01 X 10(5)/g in bison, and 1.29 X 10(6)/g in sheep. Omasal dry matter was significantly higher than ruminal dry matter in all species and ranged up to 51.5% in cattle fed high-concentrate diets. The omasal pH was similar to the ruminal pH in all species. The number of omasal laminae averaged 149, 145, and 74 for cattle, bison, and sheep, respectively. Although protozoan concentrations in omasal contents were approximately 80% lower than those in ruminal contents, the omasum harbored relatively high numbers of ciliated protozoa. The resident omasal protozoa are extremely difficult to remove, particularly in cattle, and apparently are responsible for reinoculating transiently defaunated rumens.     

Ruminal microbial populations and fermentation characteristics in bison and cattle fed high- and low-quality forage

Ruminal microbial populations and fermentation products were compared between two ruminally cannulated bison (375 kg) and two ruminally cannulated Hereford steers (567 kg) on alfalfa or prairie hay diets. Differential media were used to enumerate carbohydrate-specific bacterial subgroups. Voluntary dry matter intake was higher (P=0.006) for cattle than for bison fed alfalfa, but prairie hay intake was not different (P=0.16) between the two species. Volatile fatty acid concentrations, pH, and ruminal ammonia were similar between bison and cattle on both diets. Total anaerobic bacteria and xylanolytic bacterial counts were higher (P<0.02) in bison than in cattle fed alfalfa. However, with the prairie hay diet, no differences in bacterial counts on any medium were observed between ruminant species. Both bison and cattle possessed a mixed A-B protozoan population with nearly identical protozoan numbers and distribution of genera. The similarities between bison and cattle consuming either high-or low-quality forage suggest that any differences in putative forage digestibility between the species are not due to differences in microbial counts.     

Comparisons of ruminal fermentation characteristics and microbial populations in bison and cattle.

Ruminal microbial populations, fermentation characteristics, digestibility, and liquid flow rates in two ruminally cannulated bison and two ruminally cannulated Hereford steers fed a prairie hay diet were compared. No significant differences in anaerobic bacterial counts, volatile fatty acid concentrations, or ruminal pHs were evident between bison and cattle. Also, no significant differences in neutral detergent fiber digestibility, indigestible fiber retention time, or intake were detected between bison and cattle, although cattle had higher levels (P less than 0.08) of ruminal dry matter and indigestible fiber than bison. Bison had a smaller (P = .02) ruminoreticular volume, faster liquid dilution rates, and faster liquid turnover times than cattle. The average ruminal ammonia nitrogen concentration was higher (P = 0.02) in bison (1.17 mg/dl) than in cattle (0.79 mg/dl). Total ciliate protozoal counts and cell volume were greater (P = 0.07) in bison (32.8 x 10(4)/g and 407.1 x 10(-4) ml/g, respectively) than in cattle (15.7 x 10(4)/g and 162.2 x 10(-4) ml/g, respectively). Bison harbored higher (P less than 0.02) numbers of Dasytricha spp., Eudiplodinium maggii, Eudiplodinium bursa, and Epidinium spp. than cattle and possessed a type B protozoan population. The cattle possessed a mixed type A-type B population that was characterized by Ophryoscolex spp. and Polyplastron spp. in association with low concentrations of Epidinium spp. and Eudiplodinium maggii.     

Comparisons of ruminal fermentation characteristics and microbial populations in bison and cattle

Ruminal microbial populations, fermentation characteristics, digestibility, and liquid flow rates in two ruminally cannulated bison and two ruminally cannulated Hereford steers fed a prairie hay diet were compared. No significant differences in anaerobic bacterial counts, volatile fatty acid concentrations, or ruminal pHs were evident between bison and cattle. Also, no significant differences in neutral detergent fiber digestibility, indigestible fiber retention time, or intake were detected between bison and cattle, although cattle had higher levels (P less than 0.08) of ruminal dry matter and indigestible fiber than bison. Bison had a smaller (P = .02) ruminoreticular volume, faster liquid dilution rates, and faster liquid turnover times than cattle. The average ruminal ammonia nitrogen concentration was higher (P = 0.02) in bison (1.17 mg/dl) than in cattle (0.79 mg/dl). Total ciliate protozoal counts and cell volume were greater (P = 0.07) in bison (32.8 x 10(4)/g and 407.1 x 10(-4) ml/g, respectively) than in cattle (15.7 x 10(4)/g and 162.2 x 10(-4) ml/g, respectively). Bison harbored higher (P less than 0.02) numbers of Dasytricha spp., Eudiplodinium maggii, Eudiplodinium bursa, and Epidinium spp. than cattle and possessed a type B protozoan population. The cattle possessed a mixed type A-type B population that was characterized by Ophryoscolex spp. and Polyplastron spp. in association with low concentrations of Epidinium spp. and Eudiplodinium maggii.     

DNA fingerprinting and genetic diversity of the European bison (Bison bonasus), American bison (Bison bison), and gray Ukrainian cattle (Bos taurus)

To describe genetic variability and population diversity in domesticated populations of American bison (Bison bison), aurochs (Bison bonasus), and gray Ukrainian cattle (Bos taurus) different variants of DNA fingerprinting technique (utilizing the M13 phage DNA, (TTAGGG)4 synthetic oligonucleotide, and three arbitrary primers as hybridization probes) were used. Several parameters characterizing polymorphism and genetic diversity levels in each population (species) were evaluated on the basis of the profiles obtained. Dendrograms reflecting similarities between individual animals were constructed. Genetic variability of minisatellite and telomeric markers observed in the gray Ukrainian cattle flock was higher than that in aurochs and bisons. Comparison of the intrapopulation similarity (S) and gene diversity (H) indices along with the analysis of clusters in the dendrograms showed that the relatedness between the aurochs individuals was much higher than between the individual animals in the bison and gray Ukrainian cattle flocks. Furthermore, the gray Ukrainian cattle flock was represented by more distant relatives than the bison flock. It is suggested that reduced genetic variability and the appearance of deviant genotype observed in the two bison lines under selection, resulted from close inbreeding and the founder effect. The diagnostic value and efficacy of utilization of different molecular markers for estimation of genetic diversity and relatedness in domesticated animal populations is discussed.     

Conservation genomics: disequilibrium mapping of domestic cattle chromosomal segments in North American bison populations

Introgressive hybridization is one of the major threats to species conservation, and is often induced by human influence on the natural habitat of wildlife species. The ability to accurately identify introgression is critical to understanding its importance in evolution and effective conservation management of species. Hybridization between North American bison (Bison bison) and domestic cattle (Bos taurus) as a result of human activities has been recorded for over 100 years, and domestic cattle mitochondrial DNA was previously detected in bison populations. In this study, linked microsatellite markers were used to identify domestic cattle chromosomal segments in 14 genomic regions from 14 bison populations. Cattle nuclear introgression was identified in five populations, with an average frequency per population ranging from 0.56% to 1.80%. This study represents the first use of linked molecular markers to examine introgression between mammalian species and the first demonstration of domestic cattle nuclear introgression in bison. To date, six public bison populations have been identified with no evidence of mitochondrial or nuclear domestic cattle introgression, providing information critical to the future management of bison genetic resources. The ability to identify even low levels of introgression resulting from historic hybridization events suggests that the use of linked molecular markers to identify introgression is a significant development in the study of introgressive hybridization across a broad range of taxa.     

Immune responses after oral inoculation of weanling bison or beef calves with a bison or cattle isolate of Mycobacterium avium subsp. paratuberculosis

Paratuberculosis is endemic in domestic and wild ruminants worldwide. We designed the following study to compare host immune responses and pathologic changes in beef calves and bison calves after challenge with either a cattle or bison (Bison bison) strain of Mycobacterium avium subsp. paratuberculosis. In the first part of the study, six bison and six beef calves were orally inoculated with a cattle isolate of M. avium subsp. paratuberculosis over a 2 wk period. In the second part, an additional six bison and six beef calves were similarly inoculated with a bison strain of M. avium subsp. paratuberculosis. Throughout each of the studies, blood and fecal samples were taken monthly for a 6 mo infection period. Tissue samples were obtained at necropsy for culture and histopathologic analyses. Results from this study demonstrated that bison calves were more susceptible to tissue colonization than beef calves after challenge with the cattle isolate and, conversely, that beef calves were more susceptible to the bison strain of M. avium subsp. paratuberculosis. Although lesions were minimal they were most apparent in the jejunum and distal ileum. Interferon-gamma (IFN-gamma) responses were noted in some calves by 1 mo postinoculation and were sustained longer in beef calves after challenge with the bison isolate. Antibody was not detected in either beef or bison calves during the 6 mo infection period. These results indicate that the host response to strains of M. avium subsp. paratuberculosis may differ between ruminant species.     

Genetic Analysis of the Henry Mountains Bison Herd

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.     

Bison PRNP genotyping and potential association with Brucella spp. seroprevalence

The implication that host cellular prion protein (PrP(C)) may function as a cell surface receptor and/or portal protein for Brucella abortus in mice prompted an evaluation of nucleotide and amino acid variation within exon 3 of the prion protein gene (PRNP) for six US bison populations. A non-synonymous single nucleotide polymorphism (T50C), resulting in the predicted amino acid replacement M17T (Met --> Thr), was identified in each population. To date, no variation (T50; Met) has been detected at the corresponding exon 3 nucleotide and/or amino acid position for domestic cattle. Notably, 80% (20 of 25) of the Yellowstone National Park bison possessing the C/C genotype were Brucella spp. seropositive, representing a significant (P = 0.021) association between seropositivity and the C/C genotypic class. Moreover, significant differences in the distribution of PRNP exon 3 alleles and genotypes were detected between Yellowstone National Park bison and three bison populations that were either founded from seronegative stock or previously subjected to test-and-slaughter management to eradicate brucellosis. Unlike domestic cattle, no indel polymorphisms were detected within the corresponding regions of the putative bison PRNP promoter, intron 1, octapeptide repeat region or 3'-untranslated region for any population examined. This study provides the first evidence of a potential association between nucleotide variation within PRNP exon 3 and the presence of Brucella spp. antibodies in bison, implicating PrP(C) in the natural resistance of bison to brucellosis infection.     

Ruminal cellulolytic bacteria and protozoa from bison, cattle-bison hybrids, and cattle fed three alfalfa-corn diets.

Ruminal cellulolytic bacteria and protozoa and in vitro digestibility of alfalfa fiber fractions were compared among bison, bison hybrids, and crossbed cattle (five each) when they were fed alfalfa and corn in a ratio of 100:0, 75:25, and 50:50, respectively. The total number of viable bacteria (2.16 x 10(9) to 5.44 x 10(9)/ml of ruminal fluid) and the number of cellulolytic bacteria (3.74 x 10(7) to 10.9 x 10(7)/ml) were not different among groups of animals fed each diet. The genera of protozoa in all of the animal groups were similar; however, when either the 100:0 or 50:50 diet was used the percentage of Entodinium sp. was lower and the percentage of Diplodiniinae was higher (P less than 0.05) in bison than in bison hybrids or cattle. Bacteroides succinogenes made up the largest number of cellulolytic isolates from bison (58 and 36%, respectively, on the 100:0 and 75:25 diets), which were more numerous (P less than 0.05) than those from bison hybrids (36 and 12%) and cattle (33 and 18%). This was offset by a lower number of cellulolytic Butyrivibrio isolates. The numbers of Ruminococcus albus and R. flavefaciens isolates, in general, were similar among the bovid species, although R. flavefaciens generally made up less than 10% of the cellulolytic isolates. In vitro digestibility coefficients were greater (P less than 0.05) for the bison when the 75:25 diet was used and similar for the other two diets. The concentration of ruminal volatile fatty acids was larger (P less than 0.05) in bison than in bison hybrids and cattle when the 50:50 diet was used.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ruminal cellulolytic bacteria and protozoa from bison, cattle-bison hybrids, and cattle fed three alfalfa-corn diets

Ruminal cellulolytic bacteria and protozoa and in vitro digestibility of alfalfa fiber fractions were compared among bison, bison hybrids, and crossbed cattle (five each) when they were fed alfalfa and corn in a ratio of 100:0, 75:25, and 50:50, respectively. The total number of viable bacteria (2.16 x 10(9) to 5.44 x 10(9)/ml of ruminal fluid) and the number of cellulolytic bacteria (3.74 x 10(7) to 10.9 x 10(7)/ml) were not different among groups of animals fed each diet. The genera of protozoa in all of the animal groups were similar; however, when either the 100:0 or 50:50 diet was used the percentage of Entodinium sp. was lower and the percentage of Diplodiniinae was higher (P less than 0.05) in bison than in bison hybrids or cattle. Bacteroides succinogenes made up the largest number of cellulolytic isolates from bison (58 and 36%, respectively, on the 100:0 and 75:25 diets), which were more numerous (P less than 0.05) than those from bison hybrids (36 and 12%) and cattle (33 and 18%). This was offset by a lower number of cellulolytic Butyrivibrio isolates. The numbers of Ruminococcus albus and R. flavefaciens isolates, in general, were similar among the bovid species, although R. flavefaciens generally made up less than 10% of the cellulolytic isolates. In vitro digestibility coefficients were greater (P less than 0.05) for the bison when the 75:25 diet was used and similar for the other two diets. The concentration of ruminal volatile fatty acids was larger (P less than 0.05) in bison than in bison hybrids and cattle when the 50:50 diet was used.(ABSTRACT TRUNCATED AT 250 WORDS)     

A comprehensive evaluation of cattle introgression into US federal bison herds

Genetic introgression, especially from interspecies hybridization, is a significant threat to species conservation worldwide. In this study, 11 US federal bison populations were comprehensively examined for evidence of both mitochondrial and nuclear domestic cattle (Bos taurus) introgression. Mitochondrial introgression was examined using established polymerase chain reaction methods and confirmed through analysis of D-loop sequences. Nuclear introgression was assessed in 14 chromosomal regions through examination of microsatellite electromorph and sequence differences between bison and domestic cattle. Only one population was identified with domestic cattle mitochondrial DNA introgression. In contrast, evidence of nuclear introgression was found in 7 (63.6%) of the examined populations. Historic accounts of bison transfers among populations were corroborated with evidence of introgressed DNA transmission. While neither nuclear nor mitochondrial domestic cattle introgression was detected in bison from Grand Teton National Park, Sully's Hill National Game Preserve, Wind Cave National Park, or Yellowstone National Park, adequate sample sizes were available only from the last 2 populations to allow for statistical confidence (>90%) in nuclear introgression detection limits. The identification of genetically unique and undisturbed populations is critical to species conservation efforts, and this study serves as a model for the genetic evaluation of interspecies introgression.     

Predicting bison migration out of Yellowstone National Park using bayesian models

Long distance migrations by ungulate species often surpass the boundaries of preservation areas where conflicts with various publics lead to management actions that can threaten populations. We chose the partially migratory bison (Bison bison) population in Yellowstone National Park as an example of integrating science into management policies to better conserve migratory ungulates. Approximately 60% of these bison have been exposed to bovine brucellosis and thousands of migrants exiting the park boundary have been culled during the past two decades to reduce the risk of disease transmission to cattle. Data were assimilated using models representing competing hypotheses of bison migration during 1990-2009 in a hierarchal bayesian framework. Migration differed at the scale of herds, but a single unifying logistic model was useful for predicting migrations by both herds. Migration beyond the northern park boundary was affected by herd size, accumulated snow water equivalent, and aboveground dried biomass. Migration beyond the western park boundary was less influenced by these predictors and process model performance suggested an important control on recent migrations was excluded. Simulations of migrations over the next decade suggest that allowing increased numbers of bison beyond park boundaries during severe climate conditions may be the only means of avoiding episodic, large-scale reductions to the Yellowstone bison population in the foreseeable future. This research is an example of how long distance migration dynamics can be incorporated into improved management policies.     

Antibiotic Resistance of Enterococci in American Bison (Bison bison) from a Nature Preserve Compared to That of Enterococci in Pastured Cattle

Enterococci isolated from a bison population on a native tall-grass prairie preserve in Kansas were characterized and compared to enterococci isolated from pastured cattle. The species diversity was dominated by Enterococcus casseliflavus in bison (62.4%), while Enterococcus hirae was the most common isolate from cattle (39.7%). Enterococcus faecalis was the second most common species isolated from bison (16%). In cattle, E. faecalis and Enterococcus faecium were isolated at lower percentages (3.2% and 1.6%, respectively). No resistance to ampicillin, chloramphenicol, gentamicin, or high levels of vancomycin was detected from either source. Tetracycline and erythromycin resistance phenotypes, encoded by tetO and ermB, respectively, were common in cattle isolates (42.9% and 12.7%, respectively). A significant percentage of bison isolates (8% and 4%, respectively) were also resistant to these two antibiotics. The tetracycline resistance genes from both bison and cattle isolates resided on mobile genetic elements and showed a transfer frequency of 10⁻⁶ per donor, whereas erythromycin resistance was not transferable. Resistance to ciprofloxacin was found to be higher in enterococci from bison (14.4%) than in enterococci isolated from cattle (9.5%). The bison population can serve as a sentinel population for studying the spread and origin of antibiotic resistance.