Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| [participation of structural gene markers and anonymous dna sequences in genetic differentiation in the species ovis aries l. and ovis nivicola borealis]. | genetic variability and genetic differentiation in two ovis species--domesticated (askanian sheep, sokilska and kulunda sheep) and wild (bighorn sheep) were analyzed using different types of molecular-genetic markers--genetic-biochemical (30 loci) and dna (issr-pcr) ones. high level of genetic variability was revealed. the average heterozygosity of biochemical markers loci was in range of 0.073-0.188. markers involved into process of genofond divergence of two closely related species were reveal ... | 2000 | 11391892 |
| body mass and individual fitness in female ungulates: bigger is not always better. | in female vertebrates, differences in fitness often correspond to differences in phenotypic quality, suggesting that larger females have greater fitness. variation in individual fitness can result from variation in life span and/or variation in yearly reproductive success, but no study has yet assessed the relationships between the components of fitness and phenotypic quality while controlling for life span. we tried to fill this gap using data from long-term monitoring (23 years) of marked roe ... | 2000 | 10737404 |
| is the decline of desert bighorn sheep from infectious disease the result of low mhc variation? | bighorn sheep populations have greatly declined in numbers and distribution since european settlement, primarily because of high susceptibility to infectious diseases transmitted to them from domestic livestock. it has been suggested that low variation at major histocompatibility complex (mhc) genes, the most important genetic aspect of the vertebrate immune system, may result in high susceptibility to infectious disease. therefore, we examined genetic polymorphism at a mhc gene (ovca-drb) in a ... | 2001 | 11520344 |
| a molecular analysis of dietary diversity for three archaic native americans. | dna was extracted from three fecal samples, more than 2,000 years old, from hinds cave, texas. amplification of human mtdna sequences showed their affiliation with contemporary native americans, while sequences from pronghorn antelope, bighorn sheep, and cottontail rabbit allowed these animals to be identified as part of the diet of these individuals. furthermore, amplification of chloroplast dna sequences identified eight different plants as dietary elements. these archaic humans consumed 2-4 d ... | 2001 | 11296282 |
| founder effect in an island population of bighorn sheep. | the tiburon island population of desert bighorn sheep has increased in size from 20 founders in 1975 to approximately 650 in 1999. this population is now the only population being used as the source stock for transplantations throughout northern mexico. to evaluate the genetic variation in this population, we examined 10 microsatellite loci and a major histocompatibility complex (mhc) locus. the genetic variation was significantly less than found in other populations of the same subspecies in ar ... | 2001 | 11348494 |
| estimation of linkage disequilibrium for loci with multiple alleles: basic approach and an application using data from bighorn sheep. | the great expansion of population genetic data using molecular techniques now allows examination of the extent of linkage disequilibrium for many pairs of loci, each locus often with multiple alleles. the expectation-maximization (em) algorithm for generating maximum likelihood estimates of gametic frequencies from multiallelic genotypic data is described and applied. the em algorithm is used in desert bighorn sheep where the population size, and consequently the sample size, is often small. we ... | 2001 | 11903565 |
| incursion of epizootic hemorrhagic disease into the okanagan valley, british columbia in 1999. | in september 1999, unusually high mortality rates in white-tailed deer and california bighorn sheep occurred in the southern okanagan valley. necropsy and histopathologic findings were compatible with epizootic hemorrhagic disease (ehd); the presence of virus was not demonstrated. subsequent serologic and polymerase chain reaction assays on sentinel cattle suggested an ehd virus incursion. | 2001 | 11265190 |
| new host and geographic records for two protostrongylids in dall's sheep. | biodiversity survey and inventory have resulted in new information on the distribution of protostrongylidae in dall's sheep (ovis dalli dalli) from the northwest territories (nt, canada) and from alaska (ak, usa). in 1998, parelaphostrongylus odocoilei adults were found for the first time in the skeletal muscles of dall's sheep in the mackenzie mountains (nt). adult p. odocoilei were associated with petechial and ecchymotic hemorrhages and localized myositis; eggs and larvae in the lungs were as ... | 2001 | 11763740 |
| safety of brucella abortus strain rb51 vaccine in non-target ungulates and coyotes. | brucellosis is endemic in free-ranging elk (cervus elaphus) and bison (bison bison) in the greater yellowstone area (gya; usa). it is possible that an oral brucellosis vaccine could be developed and disseminated in the gya to reduce disease transmission. should this occur, non-target species other than elk and bison may come in contact with the vaccine resulting in morbidity or mortality. to assess biosafety, bighorn sheep (ovis canadensis; n = 10), pronghorn (antilocapra americana; n = 9), mule ... | 2002 | 12238372 |
| age-dependent sexual selection in bighorn rams. | although mating systems and sexual selection have been intensively studied in ungulate model systems, very few studies have combined genetic paternity analysis with individual phenotypic data over several breeding seasons. we used microsatellite paternity analysis to determine the parentage of 83 bighorn sheep (ovis canadensis) born between 1995 and 2000 at ram mountain, alberta, canada. we could assign the paternity of 64 lambs at a high level of statistical confidence (95%). within each season ... | 2002 | 11798432 |
| hemorrhagic disease in bighorn sheep in arizona. | two bighorn sheep from arizona (usa) were submitted for necropsy. one was a rocky mountain bighorn (ovis canadensis canadensis) and the other was a desert bighorn (ovis canadensis mexicana). both had lesions consistent with those of hemorrhagic disease (hd). epizootic hemorrhagic disease virus (ehdv) type-2 and bluetongue virus (btv) type-17, respectively, were isolated from the sheep tissues. to our knowledge, hd caused by either ehdv or btv infection has not been documented previously in arizo ... | 2002 | 11838210 |
| sexual segregation in ungulates: a comparative test of three hypotheses. | in most social ungulate species, males are larger than females and the sexes live in separate groups outside the breeding season. it is important for our understanding of the evolution of sociality to find out why sexual segregation is so widespread not only in ungulates but also in other mammals. sexual body size dimorphism was proposed as a central factor in the evolution of sexual segregation in ungulates. we tested three hypotheses put forward to explain sexual segregation: the predation-ris ... | 2002 | 11911375 |
| characterization of pasteurella multocida associated with pneumonia in bighorn sheep. | pasteurella multocida is a highly diverse group of bacteria recognized as important pathogens. although p. multocida is not ordinarily associated with disease in rocky mountain bighorn sheep (ovis canadensis canadensis), numerous isolates were cultured in high numbers from free-ranging bighorn sheep in the hells canyon area of idaho, washington, and oregon (usa) during the winter of 1995-96. animals captured in hells canyon and held in captivity, and their offspring, also harbored p. multocida. ... | 2003 | 14567214 |
| novel protease produced by a pasteurella trehalosi serotype 10 isolate from a pneumonic bighorn sheep: characteristics and potential relevance to protection. | a strain of pasteurella trehalosi serotype 10, e(co)-100, isolated from a bighorn sheep that had succumbed to pneumonic pasteurellosis during an epizootic, was compared to well-characterized strains of p. trehalosi serotype 10 and mannheimia haemolytica serotype 1. the gene for leukotoxin a (lkta) from e(co)-100 was sequenced and found to be identical on an amino acid basis to a published sequence for lkta from p. trehalosi serotype 10. however, the toxic activity in culture supernatant measured ... | 2003 | 12637002 |
| comparison of targeting f and g protein genes to detect bovine and ovine respiratory syncytial viruses. | in this study, 2 reverse transcriptase-polymerase chain reaction (rt-pcr) assays were developed and compared for simultaneous detection of bovine and ovine respiratory syncytial viruses (rsvs). one assay was based on a set of primers, which amplified a 426-bp fragment of either bovine or ovine rsv f gene (rt-pcr f). the f products could be distinguished by ecori or bstyi restriction endonuclease cleavage. in the other assay, a set of primers amplified a 542-bp fragment of either ovine or bovine ... | 2003 | 12735351 |
| infectious disease survey of gemsbok in new mexico. | exotic wildlife can introduce new diseases or act as reservoirs of endemic diseases. on white sands missile range, new mexico (usa), significant declines in populations of native ungulates generally correspond to increases in range and population density of the exotic gemsbok (oryx gazella gazella), introduced beginning in 1969. we surveyed gemsbok in 2001 for exposure to a variety of diseases potentially important for native ungulates. high seroprevalence was found for malignant catarrhal fever ... | 2003 | 14733271 |
| sharing of pasteurella spp. between free-ranging bighorn sheep and feral goats. | pasteurella spp. were isolated from feral goats and free-ranging bighorn sheep (ovis canadensis canadensis) in the hells canyon national recreation area bordering idaho, oregon, and washington (usa). biovariant 1 pasteurella haemolytica organisms were isolated from one goat and one of two bighorn sheep found in close association. both isolates produced leukotoxin and had identical electrophoretic patterns of dna fragments following cutting with restriction endonuclease haeiii. similarly pasteure ... | 2003 | 14733287 |
| undesirable evolutionary consequences of trophy hunting. | phenotype-based selective harvests, including trophy hunting, can have important implications for sustainable wildlife management if they target heritable traits. here we show that in an evolutionary response to sport hunting of bighorn trophy rams (ovis canadensis) body weight and horn size have declined significantly over time. we used quantitative genetic analyses, based on a partly genetically reconstructed pedigree from a 30-year study of a wild population in which trophy hunting targeted r ... | 2003 | 14668862 |
| variable age structure and apparent density dependence in survival of adult ungulates. | large herbivores have strongly age-structured populations. because recruitment often decreases as population density increases, in unexploited populations the proportion of older adults may increase with density. because survival senescence is typical of ungulates, ignoring density-dependent changes in age structure could lead to apparent density-dependence in adult survival. to test for density dependence in adult survival, we used data from three populations that underwent considerable changes ... | 2003 | 30893958 |
| brucellosis in captive rocky mountain bighorn sheep (ovis canadensis) caused by brucella abortus biovar 4. | nine (four female, five male) captive adult rocky mountain bighorn sheep (ovis canadensis) contracted brucellosis caused by brucella abortus biovar 4 as a result of natural exposure to an aborted elk (cervus elaphus) fetus. clinical signs of infection were orchitis and epididymitis in males and lymphadenitis and placentitis with abortion in females. gross pathologic findings included enlargement of the testes or epididymides, or both, and yellow caseous abscesses and pyogranulomas of the same. b ... | 2004 | 15362833 |
| experiments in dna extraction and pcr amplification from bighorn sheep feces: the importance of dna extraction method. | reliability of genotyping is an issue for studies using non-invasive sources of dna. we emphasize the importance of refining dna extraction methods to maximize reliability and efficiency of genotyping for such dna sources. we present a simple and general method to quantitatively compare genotyping reliability of various dna extraction techniques and sample materials used. for bighorn sheep (ovis canadensis) fecal samples we compare different fecal pellet materials, different amounts of fecal pel ... | 2004 | 15475396 |
| a population genetic comparison of argali sheep (ovis ammon) in mongolia using the nd5 gene of mitochondrial dna; implications for conservation. | we sequenced 556 bp of the mitochondrial nd5 gene to infer aspects of population structure and to test subspecific designations of argali sheep (ovis ammon) in mongolia. analysis of molecular variance (amova) revealed greater variation within than among putative subspecies and populations, suggesting high levels female-mediated gene flow. compared with bighorn sheep (o. canadensis) in north america, substantially less differentiation in mitochondrial dna was found among argali populations over 1 ... | 2004 | 15078469 |
| comparison of three fecal steroid metabolites for pregnancy detection used with single sampling in bighorn sheep (ovis canadensis). | we conpared three fecal steroid metabolite assays for their usefulness in detecting pregnalcy among free-ranging rocky mountain bighorn sheep (ovis canadensis canadensis) from bighorn canyon national recreation area, wyoming and montana (usa) and captive bighorn ewes at zoomontana in billings, montana. fecal samples were collected from 11 free-ranging, radio-collared bighorn ewes in late january-may 2001 and from 20 free-ranging, radio-collared ewes in late march to mid-may 2002. free-ranging ew ... | 2004 | 15362827 |
| new ruminant hosts and wider geographic range identified for babesia odocoilei (emerson and wright 1970). | babesia odocoilei was found to infect two previously unknown host species, desert bighorn sheep (ovis canadensis nelsoni) and musk oxen (ovibos moschatus), both of which are members of the family bovidae. previously, b. odocoilei has been reported in only cervidae hosts. new geographic regions where b. odocoilei infections have not been reported previously include pennsylvania and new york, where fatal babesiosis has occurred in reindeer (rangifer tarandus tarandus); new hampshire, where elk (ce ... | 2005 | 16456156 |
| a novel subgroup of rhadinoviruses in ruminants. | in the course of investigating the malignant catarrhal fever (mcf) subgroup of rhadinoviruses, seven novel rhadinoviruses were identified in a variety of ruminants, including domestic sheep, bighorn sheep, bison, black-tailed deer, mule deer, fallow deer, elk and addax. based on the dna polymerase gene sequences, these newly recognized viruses clustered into a second distinct subgroup in ruminants with three members identified previously in cattle, goats and oryx. phylogenetic analysis revealed ... | 2005 | 16227223 |
| the rise and fall of psoroptic scabies in bighorn sheep in the san andres mountains, new mexico. | between 1978 and 1997, a combination of psoroptic scabies (psoroptes spp.), mountain lion (puma concolor) predation, and periodic drought reduced a population of native desert bighorn sheep (ovis canadensis) in the san andres mountains (sam), new mexico, from >200 individuals to a single ewe. in 1999, this ewe was captured, ensured to be psoroptes-free, and released back into the sam. eleven radio-collared rams were translocated from the red rock wildlife area (rrwa) in new mexico into the sam r ... | 2005 | 16244062 |
| ontogenetic patterns in heritable variation for body size: using random regression models in a wild ungulate population. | body size is an important determinant of fitness in many organisms. while size will typically change over the lifetime of an individual, heritable components of phenotypic variance may also show ontogenetic variation. we estimated genetic (additive and maternal) and environmental covariance structures for a size trait (june weight) measured over the first 5 years of life in a natural population of bighorn sheep ovis canadensis. we also assessed the utility of random regression models for estimat ... | 2005 | 16475080 |
| testing marker-based estimates of heritability in the wild. | marker-based estimates of heritability are an attractive alternative to pedigree-based methods for estimating quantitative genetic parameters in field studies where it is difficult or impossible to determine relationships and pedigrees. here i test the ability of the marker-based method to estimate heritability of a suite of traits in a wild population of bighorn sheep (ovis canadensis) using marker data from 32 microsatellite loci. i compared marker-based estimates with estimates obtained using ... | 2005 | 15969737 |
| selection and genetic (co)variance in bighorn sheep. | genetic theory predicts that directional selection should deplete additive genetic variance for traits closely related to fitness, and may favor the maintenance of alleles with antagonistically pleiotropic effects on fitness-related traits. trait heritability is therefore expected to decline with the degree of association with fitness, and some genetic correlations between selected traits are expected to be negative. here we demonstrate a negative relationship between trait heritability and asso ... | 2005 | 16050112 |
| relationships among fecal lungworm loads, fecal glucocorticoid metabolites, and lamb recruitment in free-ranging rocky mountain bighorn sheep. | most wild rocky mountain big-horn sheep (ovis canadensis canadensis) in northern latitudes are infected with lungworms. indirect effects of lungworms on bighorn sheep are unknown, but high pulmonary burdens might increase stress (i.e., elevated glucocorticoid levels), and chronic stress could in turn decrease fitness. we hypothesized that high lungworm burdens in rocky mountain bighorn ewes increase stress, thereby increasing lamb mortality. to test our hypothesis, one subherd of bighorn sheep i ... | 2005 | 16107677 |
| geographic distribution of the muscle-dwelling nematode parelaphostrongylus odocoilei in north america, using molecular identification of first-stage larvae. | molecular identification of dorsal-spined larvae (dsl) from fecal samples indicates that the protostrongylid parasite parelaphostrongylus odocoilei occupies a broader geographic range in western north america than has been previously reported. we analyzed 2,124 fecal samples at 29 locations from thinhorn sheep (ovis dalli dalli and o. d. stonei), bighorn sheep (ovis canadensis canadensis and o. c. californiana), mountain goats (oreamnos americanus), woodland caribou (rangifer tarandus caribou), ... | 2005 | 16108550 |
| microbial diversity in bighorn sheep revealed by culture-independent methods. | we investigated the effectiveness of culture-independent molecular methods for determining host-associated microbial diversity in bighorn sheep (ovis canadensis). results from bacterial culture attempts have been the primary source of information on host-associated bacteria, but studies have shown that culture-based results significantly underestimate bacterial diversity in biological samples. to test the effectiveness of culture-independent methods, we extracted dna from nasal and oropharyngeal ... | 2006 | 17092885 |
| genetic rescue of an insular population of large mammals. | natural populations worldwide are increasingly fragmented by habitat loss. isolation at small population size is thought to reduce individual and population fitness via inbreeding depression. however, little is known about the time-scale over which adverse genetic effects may develop in natural populations or the number and types of traits likely to be affected. the benefits of restoring gene flow to isolates are therefore also largely unknown. in contrast, the potential costs of migration (e.g. ... | 2006 | 16777743 |
| genetic characterization of anaplasma ovis strains from bighorn sheep in montana. | wildlife reservoir species and genetic diversity of anaplasma ovis (rickettsiales: anaplasmataceae) have been poorly characterized. bighorn sheep (ovis canadensis), captured in montana from december 2004 to january 2005, were tested for antibodies to anaplasma spp.; the presence of a. ovis was determined by the characterization of major surface protein msp4 sequences. anaplasma antibodies were detected in 25/180 (14%) sampled bighorn sheep and a. ovis msp4 sequences were amplified by polymerase ... | 2006 | 16870861 |
| infectious keratoconjunctivitis in bighorn sheep, silver bell mountains, arizona, usa. | an infectious keratoconjunctivitis (ikc) epizootic in bighorn sheep (ovis canadensis) occurred in the silver bell mountains, arizona, usa, from 1 december 2003 to 31 march 2004. we used standard culture methods and polymerase chain reaction (pcr) amplification of the 16s rrna gene to test for the causative agents of ikc and other diseases reported to be associated with bighorn sheep populations. all bighorn sheep and domestic goat test results were negative except for mycoplasma spp. and branham ... | 2006 | 16870866 |
| the serologic prevalence of q fever (coxiella burnetii) complement-fixing antibodies in the peninsular bighorn sheep of southern california. | q fever is a rare illness in the southern california desert. during the past 34 years only 6 patients have been diagnosed with the disease at the eisenhower medical center, a referral center for much of the desert and surrounding mountains. in all but 2 instances, q fever was identified in patients who have been in contact with imported domestic sheep who are brought to the desert to graze and lamb in the fall and winter. the sheep are sent back to idaho, wyoming, and montana in the spring. with ... | 2006 | 16896140 |
| haemophilus somnus (histophilus somni) in bighorn sheep. | respiratory disease and poor lamb recruitment have been identified as limiting factors for bighorn-sheep populations. haemophilus somnus (recently reclassified as histophilus somni) is associated with respiratory disease in american bison, domestic sheep, and cattle. it is also harbored in their reproductive tracts and has been associated with reproductive failure in domestic sheep and cattle. therefore, reproductive tract and lung samples from bighorn sheep were evaluated for the presence of th ... | 2006 | 16548330 |
| cloning of exotic/endangered species: desert bighorn sheep. | cloning using somatic cell nuclear transfer (scnt) may be a useful tool for conserving genetic diversity and for propagating exotic and/or endangered animal species. somatic cells can be obtained easily, expanded in culture, cryopreserved, and thawed at a later date for use in nt. significant challenges relevant to using scnt for cloning wild and endangered animal species include the need for using interspecies nt and interspecies embryo transfer. animal care and welfare issues raised that are u ... | 2006 | 16988379 |
| cloning and comparison of bighorn sheep cd18 with that of domestic sheep, goats, cattle, humans and mice. | previously, we have shown that cd18, the beta-subunit of beta(2)-integrins, serves as a receptor for leukotoxin (lkt) secreted by mannheimia (pasteurella) haemolytica on bovine leukocytes. anti-cd18 monoclonal antibodies (mabs) inhibit lkt-induced cytolysis of bighorn sheep (ovis canadensis) leukocytes suggesting that cd18 may serve as a receptor for lkt on the leukocytes of this species as well. confirmation of bighorn sheep cd18 as a receptor for lkt, and elucidation of the enhanced lkt-suscep ... | 2006 | 16213032 |
| stochastic predation events and population persistence in bighorn sheep. | many studies have reported temporal changes in the relative importance of density-dependence and environmental stochasticity in affecting population growth rates, but they typically assume that the predominant factor limiting growth remains constant over long periods of time. stochastic switches in limiting factors that persist for multiple time-steps have received little attention, but most wild populations may periodically experience such switches. here, we consider the dynamics of three popul ... | 2006 | 16777749 |
| globally dispersed y chromosomal haplotypes in wild and domestic sheep. | to date, investigations of genetic diversity and the origins of domestication in sheep have utilised autosomal microsatellites and variation in the mitochondrial genome. we present the first analysis of both domestic and wild sheep using genetic markers residing on the ovine y chromosome. analysis of a single nucleotide polymorphism (oy1) in the sry promoter region revealed that allele a-oy1 was present in all wild bighorn sheep (ovis canadensis), two subspecies of thinhorn sheep (ovis dalli), e ... | 2006 | 16978172 |
| phylogenetic analysis of snow sheep (ovis nivicola) and closely related taxa. | based on mitochondrial cytochrome b gene sequence analysis, the history of true sheep (ovis) began approximately 3.12 million years ago (mya). the evolution of ovis resulted in three generally accepted genetic groups: argaliforms, moufloniforms, and pachyceriforms. the pachyceriforms of the subgenus pachyceros comprise the thin-horn sheep ovis nivicola (snow sheep), ovis dalli (dall and stone sheep), and ovis canadensis (rocky mountain and desert bighorn). north america wild sheep (o. canadensis ... | 2006 | 16267166 |
| comparative nitric oxide production by lps-stimulated monocyte-derived macrophages from ovis canadensis and ovis aries. | bighorn sheep are more susceptible to respiratory infection by mannheimia haemolytica than are domestic sheep. in response to bacterial challenge, macrophages produce a number of molecules that play key roles in the inflammatory response, including highly reactive nitrogen intermediates such as nitric oxide (no). supernatants from monocyte-derived macrophages cultured with m. haemolytica lps were assayed for nitric oxide activity via measurement of the no metabolite, nitrite. in response to lps ... | 2006 | 16460804 |
| comparative morphological study on the lingual papillae and their connective tissue cores (ctc) in reeves' muntjac deer (muntiacus reevesi). | the lingual papillae and their connective tissue cores (ctc) from reeves' muntjac deers (herbivorous artiodactyla) were studied using light and scanning electron microscopy and then compared to those of other mammalian species. at the posterior portion of the tongue, the reeves' muntjac has a lingual prominence on which large conical papillae are distributed. on the dorsal surface of the anterior tongue, numerous filiform papillae were found. externally, each filiform papilla consists of a rod-s ... | 2006 | 17140149 |
| bighorn sheep, mountain lions, and the ethics of conservation. | 2006 | 17002750 | |
| elevation and connectivity define genetic refugia for mountain sheep as climate warms. | global warming is predicted to affect the evolutionary potential of natural populations. we assessed genetic diversity of 25 populations of desert bighorn sheep (ovis canadensis nelsoni) in southeastern california, where temperatures have increased and precipitation has decreased during the 20th century. populations in low-elevation habitats had lower genetic diversity, presumably reflecting more fluctuations in population sizes and founder effects. higher-elevation habitats acted as reservoirs ... | 2006 | 17107466 |
| bighorn sheep, a new host record for parelaphostrongylus odocoilei (nematoda: protostrongylidae). | larval nematodes with a dorsal spine on the tail were recovered from fecal samples of california bighorn sheep (ovis canadensis californiana) in northeastern washington state, usa. the identity of these dorsal-spined larvae (dsl) was established by single-strand conformation polymorphism (sscp) analyses of a partial fragment of the first internal transcribed spacer of the ribosomal dna. the sscp profiles of individual dsl from bighorn sheep were compared with those of dsl of five protostrongylid ... | 2006 | 17255460 |
| histophilus somni host-parasite relationships. | histophilus somni (haemophilus somnus) is one of the key bacterial pathogens involved in the multifactorial etiology of the bovine respiratory disease complex. this gram negative pleomorphic rod also causes bovine septicemia, thrombotic meningencephalitis, myocarditis, arthritis, abortion and infertility, as well as disease in sheep, bison and bighorn sheep. virulence factors include lipooligosaccharide, immunoglobulin binding proteins (as a surface fibrillar network), a major outer membrane pro ... | 2007 | 18218158 |
| mannheimia (pasteurella) haemolytica leukotoxin utilizes cd18 as its receptor on bighorn sheep leukocytes. | pneumonia caused by mannheimia (pasteurella) haemolytica is a highly fatal disease of bighorn sheep (ovis canadensis). leukotoxin (lkt), secreted by m. haemolytica, is an important virulence factor of this organism, and is cytolytic to bighorn sheep leukocytes. previously, we have shown that cd18, the beta subunit of beta2 integrins, serves as the receptor for lkt on bovine leukocytes. furthermore, anti-cd18 antibodies inhibit lkt-induced cytotoxicity of bighorn sheep leukocytes. therefore, we h ... | 2007 | 17347395 |
| early onset of vegetation growth vs. rapid green-up: impacts on juvenile mountain ungulates. | seasonal patterns of climate and vegetation growth are expected to be altered by global warming. in alpine environments, the reproduction of birds and mammals is tightly linked to seasonality; therefore such alterations may have strong repercussions on recruitment. we used the normalized difference vegetation index (ndvi), a satellite-based measurement that correlates strongly with aboveground net primary productivity, to explore how annual variations in the timing of vegetation onset and in the ... | 2007 | 17479756 |
| cd11b of ovis canadensis and ovis aries: molecular cloning and characterization. | leukotoxin (lkt) is the primary virulence factor secreted by mannheimia haemolytica which causes pneumonia in ruminants. previously, we have shown that cd18, the beta subunit of beta(2) integrins, mediates lkt-induced cytolysis of ruminant leukocytes. cd18 associates with four distinct alpha subunits giving rise to four beta(2) integrins, cd11a/cd18 (lfa-1), cd11b/cd18 (mac-1), cd11c/cd18 (cr4), and cd11d/cd18. it is not known whether all the beta(2) integrins serve as a receptor for lkt. since ... | 2007 | 17628696 |
| selection on heritable seasonal phenotypic plasticity of body mass. | the ability to cope with environmental change is fundamental to a species' evolution. organisms can respond to seasonal environmental variation through phenotypic plasticity. the substantial plasticity in body mass of temperate species has often been considered a simple consequence of change in environmental quality, but could also have evolved as an adaptation to seasonality. we investigated the genetic basis of, and selection acting on, seasonal plasticity in body mass for wild bighorn sheep e ... | 2007 | 17683438 |
| using reproductive value to estimate key parameters in density-independent age-structured populations. | the dynamics of reproductive value are used to provide a simple derivation of tuljapurkar's approximation for the long-run growth rate and environmental variance of lnn, in a density-independent age-structured population in a random environment. with no environmental autocorrelation, the dynamics of total population size, n, generally shows time lags and autocorrelation caused by life history, which may strongly bias estimates of environmental variance obtained by ignoring age structure. in cont ... | 2007 | 16978654 |
| phylogenetic diversity of pasteurellaceae and horizontal gene transfer of leukotoxin in wild and domestic sheep. | wild and domestic animal populations are known to be sources and reservoirs of emerging diseases. there is also a growing recognition that horizontal genetic transfer (hgt) plays an important role in bacterial pathogenesis. we used molecular phylogenetic methods to assess diversity and cross-transmission rates of pasteurellaceae bacteria in populations of bighorn sheep, dall's sheep, domestic sheep and domestic goats. members of the pasteurellaceae cause an array of deadly illnesses including ba ... | 2007 | 16635591 |
| sequence analysis of the msp4 gene of anaplasma ovis strains. | anaplasma ovis (rickettsiales: anaplasmataceae) is a tick-borne pathogen of sheep, goats and wild ruminants. the genetic diversity of a. ovis strains has not been well characterized due to the lack of sequence information. in this study, we evaluated bighorn sheep (ovis canadensis) and mule deer (odocoileus hemionus) from montana for infection with a. ovis by serology and sequence analysis of the msp4 gene. antibodies to anaplasma spp. were detected in 37% and 39% of bighorn sheep and mule deer ... | 2007 | 17052866 |
| microorganisms associated with a pneumonic epizootic in rocky mountain bighorn sheep (ovis canadensis canadensis). | a comprehensive study of a pneumonic epizootic was initiated when the first signs of disease were noted in a metapopulation of bighorn sheep inhabiting hells canyon, bordering idaho, oregon, and washington. a total of 92 bighorn sheep were tested for etiologic agents during the following 6-mo study period. the study population included bighorn sheep believed to be the subpopulation in which disease was first noted, and these sheep were translocated to a holding facility in an effort to contain t ... | 2007 | 18229860 |
| bighorn sheep beta2-integrin lfa-1 serves as a receptor for mannheimia haemolytica leukotoxin. | mannheimia haemolytica is an important cause of pneumonia in bighorn sheep (bhs; ovis canadensis). leukotoxin (lkt), the primary virulence determinant of m. haemolytica, induces cytolysis of all subsets of leukocytes. previously, we have shown that cd18, the beta subunit of beta2-integrins, mediates lkt-induced cytolysis. however, it is not clear whether cd18 of all three beta2-integrins, lfa-1, mac-1, and cr4, mediates lkt-induced cytolysis. the objective of this study was to determine whether ... | 2008 | 18689665 |
| validation of an anaplasma marginale celisa for use in the diagnosis of a. ovis infections in domestic sheep and anaplasma spp. in wild ungulates. | a commercially available (celisa) kit for diagnosing anaplasma marginale infection in cattle was validated for diagnosing a ovis infection in sheep using the bovine serum controls as supplied by the manufacturer (bcelisa) and sheep serum controls from pathogen-free sheep (ocelisa). true positives were identified using two previously established assays, a nested pcr (npcr) test and an indirect immunofluorescent assay (ifa). the bcelisa was also applied to sera from various species of wild ruminan ... | 2008 | 18272296 |
| association of mycoplasma ovipneumoniae infection with population-limiting respiratory disease in free-ranging rocky mountain bighorn sheep (ovis canadensis canadensis). | bronchopneumonia is a population-limiting disease in bighorn sheep in much of western north america. previous investigators have isolated diverse bacteria from the lungs of affected sheep, but no single bacterial species is consistently present, even within single epizootics. we obtained high-quality diagnostic specimens from nine pneumonic bighorn sheep in three populations and analyzed the bacterial populations present in bronchoalveolar lavage specimens of seven by using a culture-independent ... | 2008 | 18057131 |
| quantitative genetics and sex-specific selection on sexually dimorphic traits in bighorn sheep. | sexual conflict at loci influencing traits shared between the sexes occurs when sex-specific selection pressures are antagonistic relative to the genetic correlation between the sexes. to assess whether there is sexual conflict over shared traits, we estimated heritability and intersexual genetic correlations for highly sexually dimorphic traits (horn volume and body mass) in a wild population of bighorn sheep (ovis canadensis) and quantified sex-specific selection using estimates of longevity a ... | 2008 | 18211870 |
| beta(2) integrin mac-1 is a receptor for mannheimia haemolytica leukotoxin on bovine and ovine leukocytes. | pneumonia caused by mannheimia haemolytica is an important disease of cattle (bo), domestic sheep (ds, ovis aries) and bighorn sheep (bhs, ovis canadensis). leukotoxin (lkt) produced by m. haemolytica is cytolytic to all leukocyte subsets of these three species. although it is certain that cd18, the beta subunit of beta(2) integrins, mediates lkt-induced cytolysis of leukocytes, whether cd18 of all three beta(2) integrins, lfa-1 (cd11a/cd18), mac-1 (cd11b/cd18) and cr4 (cd11c/cd18), mediates lkt ... | 2008 | 18262657 |
| ecology of gastropod and bighorn sheep hosts of lungworm on isolated, semiarid mountain ranges in utah, usa. | isolated, nonmigratory populations of bighorn sheep (ovis canadensis) may experience high exposure to lungworms (protostrongylus spp.) through a build-up of fecal material. however, semiarid climates may hinder lungworm transmission by limiting terrestrial gastropods, the intermediate hosts. we assessed potential for lungworm transmission, documented occurrence of transmission, and identified habitat types where transmission was likely to occur on ranges of two recently introduced populations of ... | 2008 | 18263819 |
| candidate gene microsatellite variation is associated with parasitism in wild bighorn sheep. | the loss of genetic variation in host populations is thought to increase host susceptibility to parasites. however, few data exist to test this hypothesis in natural populations. bighorn sheep (ovis canadensis) populations occasionally suffer disease-induced population declines, allowing us to test for the associations between reduced genetic variation and parasitism in this species. here, we show that individual mean heterozygosity for 15 microsatellite loci is associated with lungworm abundanc ... | 2008 | 18270161 |
| epidemic pasteurellosis in a bighorn sheep population coinciding with the appearance of a domestic sheep. | a pneumonia epidemic reduced bighorn sheep (ovis canadensis) survival and recruitment during 1997-2000 in a population comprised of three interconnected wintering herds (kenosha mountains, sugarloaf mountain, twin eagles) that inhabited the kenosha and tarryall mountain ranges in central colorado, usa. the onset of this epidemic coincided temporally and spatially with the appearance of a single domestic sheep (ovis aires) on the sugarloaf mountain herd's winter range in december 1997. although o ... | 2008 | 18436671 |
| never too late? consequences of late birthdate for mass and survival of bighorn lambs. | in strongly seasonal environments, the timing of birth can have important fitness consequences. we investigated which factors affect parturition date and how birthdate interacts with sex, maternal characteristics and environmental variables to affect the growth and survival of bighorn sheep (ovis canadensis) lambs in a marked population in alberta. over 14 years, the estimated birthdate of 216 lambs ranged from 21 may to 18 july. parturition date was heritable and genetically correlated with mat ... | 2008 | 18443828 |
| experimental infection of bighorn sheep with liver flukes (fasciola hepatica). | nine rocky mountain bighorn sheep (ovis canadensis canadensis) were each inoculated orally with 250 metacercariae of fasciola hepatica. blood and fecal samples were collected at the time of inoculation and at 5, 10, 14, and 20 wk after inoculation. numbers of fluke eggs in feces, hemoglobin, packed cell volume, and eosinophil values were determined. five of the bighorn sheep were treated with triclabendazole at 40 mg/kg of body weight 14 wk after inoculation. based on fecal evaluations, all bigh ... | 2009 | 19901401 |
| transmission of lungworms (muellerius capillaris) from domestic goats to bighorn sheep on common pasture. | four domestic goats (capra hircus) that were passing first-stage dorsal-spined larvae of muellerius capillaris were copastured on a 0.82-ha pasture for 11 mo from may 2003 to april 2004 with seven rocky mountain bighorn sheep (ovis canadensis) that were not passing dorsal-spined larvae. during the 11-mo experiment, two bighorn sheep died from pneumonia caused by mannheimia (pasteurella) haemolytica biotype a, serotype 2. the remaining five bighorn sheep and the four domestic goats remained healt ... | 2009 | 19395736 |
| re-sequencing regions of the ovine y chromosome in domestic and wild sheep reveals novel paternal haplotypes. | the male-specific region of the ovine y chromosome (msy) remains poorly characterized, yet sequence variants from this region have the potential to reveal the wild progenitor of domestic sheep or examples of domestic and wild paternal introgression. the 5' promoter region of the sex-determining gene sry was re-sequenced using a subset of wild sheep including bighorn (ovis canadensis), thinhorn (ovis dalli spp.), urial (ovis vignei), argali (ovis ammon), mouflon (ovis musimon) and domestic sheep ... | 2009 | 19016675 |
| age-dependent relationship between horn growth and survival in wild sheep. | 1. trade-offs in resource allocation underline the evolution of life-history traits but their expression is frequently challenged by empirical findings. in large herbivores, males with large antlers or horns typically have high mating success. the fitness costs of large horns or antlers have rarely been quantified although they are controversial. 2. here, using detailed longitudinal data on n = 172 bighorn (ovis canadensis, shaw) and the capture-mark-recapture methodology, we tested whether earl ... | 2009 | 19120602 |
| predicting population survival under future climate change: density dependence, drought and extraction in an insular bighorn sheep. | 1. our understanding of the interplay between density dependence, climatic perturbations, and conservation practices on the dynamics of small populations is still limited. this can result in uninformed strategies that put endangered populations at risk. moreover, the data available for a large number of populations in such circumstances are sparse and mined with missing data. under the current climate change scenarios, it is essential to develop appropriate inferential methods that can make use ... | 2009 | 19245378 |
| variation in pasteurella (bibersteinia) and mannheimia spp. following transport and antibiotic treatment in free-ranging and captive rocky mountain bighorn sheep (ovis canadensis canadensis). | morbidity and mortality associated with respiratory disease following capture and translocation of bighorn sheep (ovis canadensis canadensis) is a significant concern, particularly when establishing new or augmenting existing bighorn populations. administration of prophylactic antibiotics at the time of capture is often done to minimize the risk of respiratory disease, but the efficacy of this practice is unknown. the effects of oxytetracycline and florfenicol on the pasteurella (bibersteinia) a ... | 2009 | 19368250 |
| male personality, life-history strategies and reproductive success in a promiscuous mammal. | recent theoretical work suggests that personality is a component of life history, but links between personality and either age-dependent reproductive success or life-history strategy are yet to be established. using quantitative genetic analyses on a long-term pedigree we estimated indices of boldness and docility for 105 bighorn sheep rams (ovis canadensis), born between 1983 and 1999, and compared these indices to their reproductive history from 2 years of age until death. docility and boldnes ... | 2009 | 19555442 |
| first isolation of histophilus somni from goats. | histophilus somni (former name: haemophilus somnus) is a gram-negative, facultative pathogen bacterium that colonises the mucous membranes of cattle and sheep, however it was also described in american bison and bighorn sheep. it can cause local or generalised diseases and asymptomatic carriers can also occur. the presence and the etiological role of this microorganism have not been confirmed in any other domesticated species yet. the purpose of this study was to prove the presence of h. somni i ... | 2009 | 18774660 |
| an ecologic study comparing distribution of pasteurella trehalosi and mannheimia haemolytica between sierra nevada bighorn sheep, white mountain bighorn sheep, and domestic sheep. | the prevalence and phenotypic variability of pasteurella and mannheimia isolates from sierra nevada bighorn sheep (ovis canadensis sierrae), white mountain bighorn sheep (ovis canadensis nelsoni), and domestic sheep (ovis aries) from california, usa, were compared. the white mountain bighorn sheep population had a recent history of pneumonia-associated mortality, whereas the sierra nevada bighorn sheep population had no recent history of pneumonia-associated mortality. the domestic sheep flocks ... | 2009 | 19901369 |
| puma predation on radiocollared and uncollared bighorn sheep. | we used global positioning system (gps) data from radiocollared pumas (puma concolor) to identify kill sites of pumas preying upon an endangered population of bighorn sheep (ovis canadensis) in southern california. our aims were to test whether or not pumas selected radiocollared versus uncollared bighorn sheep, and to identify patterns of movement before, during, and after kills. | 2009 | 19922659 |
| individual variation in reproductive costs of reproduction: high-quality females always do better. | 1. although life-history theory predicts substantial costs of reproduction, individuals often show positive correlations among life-history traits, rather than trade-offs. the apparent absence of reproductive costs may result from heterogeneity in individual quality. 2. using detailed longitudinal data from three contrasted ungulate populations (mountain goats, oreamnos americanus; bighorn sheep, ovis canadensis; and roe deer, capreolus capreolus), we assessed how individual quality affects the ... | 2009 | 18700872 |
| effects of selenium supplementation and sample storage time on blood indices of selenium status in bighorn sheep. | periodic pneumonia outbreaks cause large-scale die-offs that threaten the viability of bighorn sheep (ovis canadensis) populations. bighorns are highly susceptible to pneumonia, and in some cases this susceptibility may be exacerbated by trace mineral deficiencies. to evaluate responses to injectable selenium supplementation, eight captive bighorn sheep were treated with either an injectable sodium selenite supplement or a saline control. we collected 6-ml blood aliquots before and at 1, 6, and ... | 2009 | 19617491 |
| mannheimia haemolytica serotype a1 exhibits differential pathogenicity in two related species, ovis canadensis and ovis aries. | mannheimia haemolytica causes pneumonia in both bighorn sheep (bhs, ovis canadensis) and domestic sheep (ds, ovis aries). under experimental conditions, co-pasturing of bhs and ds results in fatal pneumonia in bhs. it is conceivable that certain serotypes of m. haemolytica carried by ds are non-pathogenic to them, but lethal for bhs. m. haemolytica serotypes a1 and a2 are carried by ds in the nasopharynx. however, it is the serotype a2 that predominantly causes pneumonia in ds. the objectives of ... | 2009 | 18771862 |
| individual quality, early-life conditions, and reproductive success in contrasted populations of large herbivores. | variations among individuals in phenotypic quality and fitness often confound analyses of life-history strategies assessed at the population level. we used detailed long-term data from three populations of large herbivores with generation times ranging from four to nine years to quantify heterogeneity in individual quality among females, and to assess its influence on mean annual reproductive success over the lifetime (mrs). we also determined how environmental conditions in early life shaped in ... | 2009 | 19694145 |
| modeling utilization distributions in space and time. | w. van winkle defined the utilization distribution (ud) as a probability density that gives an animal's relative frequency of occurrence in a two-dimensional (x, y) plane. we extend van winkle's work by redefining the ud as the relative frequency distribution of an animal's occurrence in all four dimensions of space and time. we then describe a product kernel model estimation method, devising a novel kernel from the wrapped cauchy distribution to handle circularly distributed temporal covariates ... | 2009 | 19694144 |
| genome-wide cross-amplification of domestic sheep microsatellites in bighorn sheep and mountain goats. | we tested for cross-species amplification of microsatellite loci located throughout the domestic sheep (ovis aries) genome in two north american mountain ungulates (bighorn sheep, ovis canadensis, and mountain goats, oreamnos americanus). we identified 247 new polymorphic markers in bighorn sheep (≥ 3 alleles in one of two study populations) and 149 in mountain goats (≥ 2 alleles in a single study population) using 648 and 576 primer pairs, respectively. our efforts increased the number of avail ... | 2009 | 21564850 |
| molecular cloning of cd18 of bison, deer and elk, and comparison with that of other ruminants and non-ruminants. | pneumonia caused by mannheimia haemolytica is an important disease of cattle, domestic sheep, bighorn sheep and goats. leukotoxin (lkt) produced by m. haemolytica is cytolytic to all leukocyte subsets of these species. lkt utilizes cd18, the beta subunit of beta(2)-integrins, as its functional receptor on leukocytes of these species. cytotoxicity assays revealed that leukocytes from bison, deer, and elk are also susceptible to lkt-induced cytolysis. the availability of cdna encoding cd18 of biso ... | 2010 | 20176404 |
| mycoplasma ovipneumoniae can predispose bighorn sheep to fatal mannheimia haemolytica pneumonia. | mycoplasma ovipneumoniae has been isolated from the lungs of pneumonic bighorn sheep (bhs). however experimental reproduction of fatal pneumonia in bhs with m. ovipneumoniae was not successful. therefore the specific role, if any, of m. ovipneumoniae in bhs pneumonia is unclear. the objective of this study was to determine whether m. ovipneumoniae alone causes fatal pneumonia in bhs, or predisposes them to infection by mannheimia haemolytica. we chose m. haemolytica for this study because of its ... | 2010 | 20466492 |
| differential expression of interleukin-8 by polymorphonuclear leukocytes of two closely related species, ovis canadensis and ovis aries, in response to mannheimia haemolytica infection. | the pneumonic lesions and mortality caused by mannheimia haemolytica in bighorn sheep (bhs; ovis canadensis) are more severe than those in the related species, domestic sheep (ds; ovis aries), under both natural and experimental conditions. leukotoxin (lkt) and lipopolysaccharide (lps) are the most important virulence factors of this organism. one hallmark of pathogenesis of pneumonia is the influx of polymorphonuclear leukocytes (pmns) into the lungs. lkt-induced cytolysis of pmns results in th ... | 2010 | 20515932 |
| molecular cloning, characterization and in vitro expression of serpin b1 of bighorn sheep (ovis canadensis) and domestic sheep (ovis aries), and comparison with that of other species. | mannheimia haemolytica infection results in enhanced pmn-mediated tissue damage in the lungs of bighorn sheep (bhs) compared to that of domestic sheep (ds). serpin b1 is an inhibitor of pmn-derived serine proteases. it prevents lung tissue injury by inhibiting the serine proteases released as a result of pmn lysis and degranulation. it is conceivable that pmns of bhs exhibit decreased quantity and/or activity of serpin b1 which results in enhanced tissue injury and decreased bacterial clearance ... | 2010 | 20591503 |
| transmission of mannheimia haemolytica from domestic sheep (ovis aries) to bighorn sheep (ovis canadensis): unequivocal demonstration with green fluorescent protein-tagged organisms. | previous studies demonstrated that bighorn sheep (ovis canadensis) died of pneumonia when commingled with domestic sheep (ovis aries) but did not conclusively prove that the responsible pathogens were transmitted from domestic to bighorn sheep. the objective of this study was to determine, unambiguously, whether mannheimia haemolytica can be transmitted from domestic to bighorn sheep when they commingle. four isolates of m. haemolytica were obtained from the pharynx of two of four domestic sheep ... | 2010 | 20688676 |
| mortality during epizootics in bighorn sheep: effects of initial population size and cause. | one of the most severe threats to bighorn sheep (ovis canadensis) populations is disease. with the objective of projecting possible epizootic consequences to bighorn sheep population dynamics, we examined 23 epizootic mortality episodes from presumably known causes that occurred in the united states and canada from 1942 to 2005. these outbreaks were correlated with population size using regression models. epizootic origins were documented by considering contact with a "new" pathogen for the bigh ... | 2010 | 20688682 |
| bighorn ewes transfer the costs of reproduction to their lambs. | several studies of large mammals report no direct reproductive costs for females. individual heterogeneity may hide fitness costs of reproduction, but mothers could also transfer some costs to their offspring. using data on 442 lambs weaned by 146 bighorn sheep (ovis canadensis) ewes at ram mountain, alberta, we studied how reproductive effort varied with environmental and maternal conditions. during summer, lactating ewes should gain enough mass to survive the winter and to support their next g ... | 2010 | 20735260 |
| population-specific vital rate contributions influence management of an endangered ungulate. | to develop effective management strategies for the recovery of threatened and endangered species, it is critical to identify those vital rates (survival and reproductive parameters) responsible for poor population performance and those whose increase will most efficiently change a population's trajectory. in actual application, however, approaches identifying key vital rates are often limited by inadequate demographic data, by unrealistic assumptions of asymptotic population dynamics, and of equ ... | 2010 | 20945773 |
| genetic linkage map of a wild genome: genomic structure, recombination and sexual dimorphism in bighorn sheep. | the construction of genetic linkage maps in free-living populations is a promising tool for the study of evolution. however, such maps are rare because it is difficult to develop both wild pedigrees and corresponding sets of molecular markers that are sufficiently large. we took advantage of two long-term field studies of pedigreed individuals and genomic resources originally developed for domestic sheep (ovis aries) to construct a linkage map for bighorn sheep, ovis canadensis. we then assessed ... | 2010 | 20920197 |
| a bighorn sheep die-off in southern colorado involving a pasteurellaceae strain that may have originated from syntopic cattle. | we investigated a pasteurellosis epizootic in free-ranging bighorn sheep (ovis canadensis) wherein a pasteurellaceae strain carried by syntopic cattle (bos taurus) under severe winter conditions appeared to contribute to pneumonia in affected bighorns. twenty-one moribund or dead bighorn sheep were found on the "fossil ridge" herd's winter range, colorado, usa, between 13 december 2007 and 29 february 2008. eight carcasses examined showed gross or microscopic evidence of acute to subacute fibrin ... | 2010 | 20966277 |
| sex-differential effects of inbreeding on overwinter survival, birth date and mass of bighorn lambs. | although it is generally expected that inbreeding would lower fitness, few studies have directly quantified the effects of inbreeding in wild mammals. we investigated the effects of inbreeding using long-term data from bighorn sheep on ram mountain, alberta, canada, over 20 years. this population underwent a drastic decline from 1992 to 2002 and has since failed to recover. we used a pedigree to calculate inbreeding coefficients and examined their impact on lamb growth, birth date and survival. ... | 2010 | 21044200 |
| the effects of water and microstructure on the mechanical properties of bighorn sheep (ovis canadensis) horn keratin. | the function of the bighorn sheep horn prompted quantification of the various parametric effects important to the microstructure and mechanical property relationships of this horn. these parameters included analysis of the stress-state dependence with the horn keratin tested under tension and compression, the anisotropy of the material structure and mechanical behavior, the spatial location along the horn, and the wet-dry horn behavior. the mechanical properties of interest were the elastic modu ... | 2010 | 21095245 |
| paranasal sinus masses of rocky mountain bighorn sheep (ovis canadensis canadensis). | this article describes 10 cases of paranasal sinus masses in rocky mountain bighorn sheep (ovis canadensis canadensis). among 21 bighorns that were examined from 11 herds in colorado, 10 individuals (48%) from 4 herds (36%) had masses arising from the paranasal sinuses. affected animals included 9 of 17 females (53%) and 1 of 4 males (25%), ranging in age from approximately 2 years to greater than 10 years. defining gross features of these masses included unilateral or bilateral diffuse thickeni ... | 2010 | 20926735 |
| bibersteinia trehalosi inhibits the growth of mannheimia haemolytica by a proximity-dependent mechanism. | mannheimia (pasteurella) haemolytica is the only pathogen that consistently causes severe bronchopneumonia and rapid death of bighorn sheep (bhs; ovis canadensis) under experimental conditions. paradoxically, bibersteinia (pasteurella) trehalosi and pasteurella multocida have been isolated from bhs pneumonic lungs much more frequently than m. haemolytica. these observations suggest that there may be an interaction between these bacteria, and we hypothesized that b. trehalosi overgrows or otherwi ... | 2010 | 20038698 |
| microstructure, elastic properties and deformation mechanisms of horn keratin. | the structure and mechanical properties of the horns from a desert bighorn sheep, ovis canadensis, were examined. horns must be strong and durable as they are subjected to extreme loading impacts, making them superior structural materials. horns are composed of alpha-keratin, a fibrous, structural protein found in hair, nails, claws and hooves. horns have a lamellar structure (2-5microm in thickness) stacked in the radial direction with tubules (approximately 40x100microm in diameter) dispersed ... | 2010 | 19577667 |
| potential effects of the united states-mexico border fence on wildlife. | security infrastructure along international boundaries threatens to degrade connectivity for wildlife. to explore potential effects of a fence under construction along the u.s.-mexico border on wildlife, we assessed movement behavior of two species with different life histories whose regional persistence may depend on transboundary movements. we used radiotelemetry to assess how vegetation and landscape structure affect flight and natal dispersal behaviors of ferruginous pygmy-owls (glaucidium b ... | 2010 | 19558522 |
| molecular cloning of interleukin-1β, interleukin-8, and tumor necrosis factor-α of bighorn sheep (ovis canadensis) and comparison with those of other species. | the susceptibility to, and pathology induced by, mannheimia haemolytica infection in bighorn sheep (bhs) and domestic sheep (ds) are distinctly different. bighorn sheep are particularly susceptible to pneumonia caused by m. haemolytica, and the pneumonic lesions in infected bhs are more severe than those in ds. the molecular basis for this disparity has not been elucidated. proinflammatory cytokines have been implicated in the pathogenesis of multiple lung diseases of humans and animals. it is p ... | 2010 | 20655598 |
| muellerius capillaris dominates the lungworm community of bighorn sheep at the national bison range, montana. | lungworm infections are common among bighorn sheep (ovis canadensis) in north america, and the predominant species reported are protostrongylus stilesi and p. rushi. the only records of another lungworm species, muellerius capillaris, infecting bighorns come from south dakota, usa. at the national bison range (nbr), montana, usa we found that across six sampling periods, 100% of wild bighorn sheep surveyed were passing first-stage dorsal-spined larvae (dsl) which appeared to be consistent with m ... | 2010 | 20688711 |
| bighorn sheep fetal lung cell line for detection of respiratory viruses. | pneumonia is an important disease of bighorn sheep (bhs) that is primarily responsible for the drastic decline in numbers of these animals in north america. members of the genus mannheimia and pasteurella have frequently been isolated from the pneumonic lungs of bhs. antibodies to several respiratory viruses, including bovine parainfluenza virus 3 (bpiv-3), bovine respiratory syncytial virus (brsv), bovine viral diarrhea virus (bvdv), and bovine herpesvirus 1 (bohv-1), have been detected in herd ... | 2010 | 20357964 |