| comparison of passively transferred antibodies in bighorn and domestic lambs reveals one factor in differential susceptibility of these species to mannheimia haemolytica-induced pneumonia. | mannheimia haemolytica consistently causes fatal bronchopneumonia in bighorn sheep (bhs, ovis canadensis) under natural and experimental conditions. leukotoxin is the primary virulence factor of this organism. bhs are more susceptible to developing fatal pneumonia in comparison to the related species domestic sheep (ds, ovis aries). in bhs herds affected by pneumonia, lamb recruitment is severely impaired for years subsequent to an outbreak. we hypothesized that a lack of maternally derived anti ... | 2011 | 21613459 |
| sex ratio bias and reproductive strategies: what sex to produce when? | several theories predict the evolution of bias in progeny sex ratio based on variations in maternal or offspring reproductive value. for mammals, however, tests of sex-bias theories have produced inconsistent results, and no clear patterns have emerged. each theory is based on assumptions that are difficult to satisfy, and empirical tests require large data sets. using a long-term study on bighorn sheep (ovis canadensis), we identified several parameters that influence progeny sex ratio accordin ... | 2011 | 21618923 |
| a multivalent mannheimia/bibersteinia vaccine protects bighorn sheep against mannheimia haemolytica challenge. | bighorn sheep (bhs) are more susceptible than domestic sheep (ds) to mannheimia haemolytica pneumonia. although both species carry m. haemolytica as a commensal bacterium in the nasopharynx, ds carry mostly leukotoxin (lkt)-positive strains while bhs carry lkt-negative strains. consequently, antibodies to surface antigens and lkt are present at much higher titers in ds, but lower in bhs. the objective of this study was to determine whether repeated immunization of bhs with multivalent mannheimia ... | 2011 | 21832104 |
| pasteurellaceae from colorado bighorn sheep herds. | we compared phenotypic and genotypic characterizations of 88 pasteurellaceae isolates from bighorn sheep (ovis canadensis) in the course of exploring epizootiologic relationships. based on our observations, adopting contemporary taxonomic conventions and using molecular methods to detect and compare pasteurellaceae may help improve understanding of bighorn respiratory disease epizootiology and management. | 2011 | 21719858 |
| defective bacterial clearance is responsible for the enhanced lung pathology characteristic of mannheimia haemolytica pneumonia in bighorn sheep. | the molecular and cellular basis for the enhanced lung pathology and mortality caused by mannheimia haemolytica in bighorn sheep (bhs, ovis canadenesis), in comparison to domestic sheep (ds, ovis aries), is not clear. polymorphonuclear leukocytes (pmns) of bhs are four- to eight-fold more susceptible to m. haemolytica leukotoxin-induced cytolysis, which is likely to reduce the number of functional phagocytes in the lung. we hypothesized that enhanced lung pathology is due to defective clearance ... | 2011 | 21742446 |
| Common functional correlates of head-strike behavior in the pachycephalosaur Stegoceras validum (Ornithischia, Dinosauria) and combative artiodactyls. | Pachycephalosaurs were bipedal herbivorous dinosaurs with bony domes on their heads, suggestive of head-butting as seen in bighorn sheep and musk oxen. Previous biomechanical studies indicate potential for pachycephalosaur head-butting, but bone histology appears to contradict the behavior in young and old individuals. Comparing pachycephalosaurs with fighting artiodactyls tests for common correlates of head-butting in their cranial structure and mechanics. | 2011 | 21738658 |
| Translating effects of inbreeding depression on component vital rates to overall population growth in endangered bighorn sheep. | Evidence of inbreeding depression is commonly detected from the fitness traits of animals, yet its effects on population growth rates of endangered species are rarely assessed. We examined whether inbreeding depression was affecting Sierra Nevada bighorn sheep (Ovis canadensis sierrae), a subspecies listed as endangered under the U.S. Endangered Species Act. Our objectives were to characterize genetic variation in this subspecies; test whether inbreeding depression affects bighorn sheep vital ra ... | 2011 | 22070275 |
| short reads, circular genome: skimming solid sequence to construct the bighorn sheep mitochondrial genome. | as sequencing technology improves, an increasing number of projects aim to generate full genome sequence, even for nonmodel taxa. these projects may be feasibly conducted at lower read depths if the alignment can be aided by previously developed genomic resources from a closely related species. we investigated the feasibility of constructing a complete mitochondrial (mt) genome without preamplification or other targeting of the sequence. here we present a full mt genome sequence (16,463 nucleoti ... | 2012 | 21948953 |
| shared bacterial and viral respiratory agents in bighorn sheep (ovis canadensis), domestic sheep (ovis aries), and goats (capra hircus) in montana. | transmission of infectious agents from livestock reservoirs has been hypothesized to cause respiratory disease outbreaks in bighorn sheep (ovis canadensis), and land management policies intended to limit this transmission have proven controversial. this cross-sectional study compares the infectious agents present in multiple populations of bighorn sheep near to and distant from their interface with domestic sheep (o. aries) and domestic goat (capra hircus) and provides critical baseline informat ... | 2011 | 22195293 |
| qtl mapping for sexually dimorphic fitness-related traits in wild bighorn sheep. | dissecting the genetic architecture of fitness-related traits in wild populations is key to understanding evolution and the mechanisms maintaining adaptive genetic variation. we took advantage of a recently developed genetic linkage map and phenotypic information from wild pedigreed individuals from ram mountain, alberta, canada, to study the genetic architecture of ecologically important traits (horn volume, length, base circumference and body mass) in bighorn sheep. in addition to estimating s ... | 2011 | 21847139 |
| rapid decrease in horn size of bighorn sheep: environmental decline, inbreeding depression, or evolutionary response to trophy hunting? | there are numerous examples demonstrating that selection has greatly influenced phenotypes in wild-harvested species. here, a significant reduction in horn size in trophy desert bighorn sheep rams over 30 years in a reintroduced population in aravaipa canyon, arizona is documented. after examining the potential effects of a detrimental change in the environment, inbreeding depression, and hunter-caused evolutionary change, it appears that environmental deterioration, apparently from the effects ... | 2011 | 21900210 |
| Bighorn sheep from Yakutia. | | 2011 | 21953234 |
| patterns of body mass senescence and selective disappearance differ among three species of free-living ungulates. | declines in survival and reproduction with age are prevalent in wild vertebrates, but we know little about longitudinal changes in behavioral, morphological, or physiological variables that may explain these demographic declines. we compared age-related variation in body mass of adult females in three free-living ungulate populations that have been the focus of long-term, individual-based research: bighorn sheep (ovis canadensis) at ram mountain, canada; roe deer (capreolus capreolus) at trois f ... | 2011 | 22073785 |
| survival of bighorn sheep (ovis canadensis) commingled with domestic sheep (ovis aries) in the absence of mycoplasma ovipneumoniae. | to test the hypothesis that mycoplasma ovipneumoniae is an important agent of the bighorn sheep (ovis canadensis) pneumonia that has previously inevitably followed experimental commingling with domestic sheep (ovis aries), we commingled m. ovipneumoniae-free domestic and bighorn sheep (n=4 each). one bighorn sheep died with acute pneumonia 90 days after commingling, but the other three remained healthy for >100 days. this unprecedented survival rate is significantly different (p=0.002) from that ... | 2012 | 22247385 |
| occurrence, diagnosis, and strain typing of mycobacterium avium subspecies paratuberculosis infection in rocky mountain bighorn sheep (ovis canadensis canadensis) in southwestern alberta. | the role that wildlife may play in the transmission of mycobacterium avium subspecies paratuberculosis (map), the causative agent of johne's disease (jd), and the potential consequences of infection in these populations are being given increasing consideration. a yearling male rocky mountain bighorn sheep (ovis canadensis canadensis) from southwestern alberta, canada, was found infected with map in august 2009. clinical signs of emaciation and diarrhea and histologic findings of diffuse granulom ... | 2012 | 22247368 |
| genomic consequences of genetic rescue in an insular population of bighorn sheep (ovis canadensis). | genetic rescue is a management intervention whereby a small population is supplemented with individuals from other populations in an attempt to reverse the effects of inbreeding and increased genetic load. one such rescue was recently documented in the population of bighorn sheep (ovis canadensis) within the national bison range wildlife refuge (montana, usa). here, we examine the locus-specific effects of rescue in this population using a newly developed genome-wide set of 195 microsatellite lo ... | 2012 | 22257293 |
| acylation enhances, but is not required for, the cytotoxic activity of mannheimia haemolytica leukotoxin in bighorn sheep. | mannheimia haemolytica causes pneumonia in domestic and wild ruminants. leukotoxin (lkt) is the most important virulence factor of the bacterium. it is encoded within the four-gene lktcabd operon: lkta encodes the structural protoxin, and lktc encodes a trans-acylase that adds fatty acid chains to internal lysine residues in the protoxin, which is then secreted from the cell by a type 1 secretion system apparatus encoded by lktb and lktd. it has been reported that lktc-mediated acylation is nece ... | 2015 | 26216418 |
| reinstatement of dermacentor kamshadalus neumann (acari: ixodidae) as a valid species parasitizing mountain goats and sheep in the united states, canada, and russia. | reexamination of dermacentor albipictus (packard, 1869) holdings stored in the united states national tick collection revealed several collections of a morphologically distinct dermacentor species. comparison of these specimens with other dermacentor taxa showed that they are identical to an old taxon originally described as dermacentor variegatus kamshadalus neumann, 1908. for more than a century, this taxon was known only from the male holotype specimen collected in russia, and the name was co ... | 0 | 23926766 |
| harnessing cross-species alignment to discover snps and generate a draft genome sequence of a bighorn sheep (ovis canadensis). | whole genome sequences (wgs) have proliferated as sequencing technology continues to improve and costs decline. while many wgs of model or domestic organisms have been produced, a growing number of non-model species are also being sequenced. in the absence of a reference, construction of a genome sequence necessitates de novo assembly which may be beyond the ability of many labs due to the large volumes of raw sequence data and extensive bioinformatics required. in contrast, the presence of a re ... | 2015 | 25990117 |
| local extinction and unintentional rewilding of bighorn sheep (ovis canadensis) on a desert island. | bighorn sheep (ovis canadensis) were not known to live on tiburón island, the largest island in the gulf of california and mexico, prior to the surprisingly successful introduction of 20 individuals as a conservation measure in 1975. today, a stable island population of ∼500 sheep supports limited big game hunting and restocking of depleted areas on the mexican mainland. we discovered fossil dung morphologically similar to that of bighorn sheep in a dung mat deposit from mojet cave, in the mount ... | 2014 | 24646515 |
| disease and predation: sorting out causes of a bighorn sheep (ovis canadensis) decline. | estimating survival and documenting causes and timing of mortality events in neonate bighorn sheep (ovis canadensis) improves understanding of population ecology and factors influencing recruitment. during 2010-2012, we captured and radiocollared 74 neonates in the black hills, south dakota, of which 95% (70) died before 52 weeks of age. pneumonia (36%) was the leading cause of mortality followed by predation (30%). we used known fate analysis in program mark to estimate weekly survival rates an ... | 2014 | 24516623 |
| effective population size, genetic variation, and their relevance for conservation: the bighorn sheep in tiburon island and comparisons with managed artiodactyls. | the amount of genetic diversity in a finite biological population mostly depends on the interactions among evolutionary forces and the effective population size (n(e)) as well as the time since population establishment. because the n(e) estimation helps to explore population demographic history, and allows one to predict the behavior of genetic diversity through time, n(e) is a key parameter for the genetic management of small and isolated populations. here, we explored an n(e)-based approach us ... | 2013 | 24147115 |
| a quantitative trait locus analysis of personality in wild bighorn sheep. | personality, the presence of persistent behav105ioral differences among individuals over time or contexts, potentially has important ecological and evolutionary consequences. however, a lack of knowledge about its genetic architecture limits our ability to understand its origin, evolution, and maintenance. here, we report on a genome-wide quantitative trait locus (qtl) analysis for two personality traits, docility and boldness, in free-living female bighorn sheep from ram mountain, alberta, cana ... | 2013 | 23531519 |
| safety and immunogenicity of a mycoplasma ovipneumoniae bacterin for domestic sheep (ovis aries). | mortality from epizootic pneumonia is hindering re-establishment of bighorn sheep populations in western north america. mycoplasma ovipneumoniae, a primary agent of this disease, is frequently carried asymptomatically by the domestic sheep and goats that constitute the reservoir of this agent for transmission to bighorn sheep. our long-term objective is to reduce the risk of m. ovipneumoniae infection of bighorn sheep; one approach to this objective is to control the pathogen in its reservoir ho ... | 2014 | 24752006 |
| temporal dynamics of linkage disequilibrium in two populations of bighorn sheep. | linkage disequilibrium (ld) is the nonrandom association of alleles at two markers. patterns of ld have biological implications as well as practical ones when designing association studies or conservation programs aimed at identifying the genetic basis of fitness differences within and among populations. however, the temporal dynamics of ld in wild populations has received little empirical attention. in this study, we examined the overall extent of ld, the effect of sample size on the accuracy a ... | 0 | 26380673 |
| potential foraging decisions by a desert ungulate to balance water and nutrient intake in a water-stressed environment. | arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. when surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. we compared two desert bighorn sheep (ovis canadensis nelsoni) populations in arizona, usa: a treatment population with supplemental water ... | 2016 | 26894504 |
| intense selective hunting leads to artificial evolution in horn size. | the potential for selective harvests to induce rapid evolutionary change is an important question for conservation and evolutionary biology, with numerous biological, social and economic implications. we analyze 39 years of phenotypic data on horn size in bighorn sheep (ovis canadensis) subject to intense trophy hunting for 23 years, after which harvests nearly ceased. our analyses revealed a significant decline in genetic value for horn length of rams, consistent with an evolutionary response t ... | 2016 | 27099619 |
| data from selective harvests underestimate temporal trends in quantitative traits. | human harvests can select against phenotypes favoured by natural selection, and natural resource managers should evaluate possible artificial selection on wild populations. because the required genetic data are extremely difficult to gather, however, managers typically rely on harvested animals to document temporal trends. it is usually unknown whether these data are unbiased. we explore our ability to detect a decline in horn size of bighorn sheep (ovis canadensis) by comparing harvested males ... | 2012 | 22552634 |
| bartonella melophagi in blood of domestic sheep (ovis aries) and sheep keds (melophagus ovinus) from the southwestern us: cultures, genetic characterization, and ecological connections. | bartonella melophagi sp. nov. was isolated from domestic sheep blood and from sheep keds (melophagus ovinus) from the southwestern united states. the sequence analyses of the reference strain performed by six molecular markers consistently demonstrated that b. melophagi relates to but differ from other bartonella species isolated from domestic and wild ruminants. presence of 183 genes specific for b. melophagi, being absent in genomes of other bartonella species associated with ruminants also su ... | 2016 | 27283855 |
| assessing timing and causes of neonatal lamb losses in a bighorn sheep ovis canadensis canadensis herd via use of vaginal implant transmitters. | we evaluated the use of vaginal implant transmitters (vits) as a means of detecting, capturing, and radio collaring rocky mountain bighorn sheep ( ovis canadensis canadensis) lambs to estimate survival and to facilitate carcass recovery to assess causes of mortality. we focused on one of several bighorn herds in colorado, usa, suffering from depressed recruitment that was not preceded by a classic all-age die-off. we captured, radio-collared, diagnosed pregnancy by ultrasound examination, and in ... | 2017 | 28192042 |
| how respiratory pathogens contribute to lamb mortality in a poorly performing bighorn sheep ( ovis canadensis ) herd. | we evaluated bighorn sheep ( ovis canadensis ) ewes and their lambs in captivity to examine the sources and roles of respiratory pathogens causing lamb mortality in a poorly performing herd. after seven consecutive years of observed december recruitments of <10%, 13 adult female bighorn sheep from the remnant gribbles park herd in colorado, us were captured and transported to the thorne-williams wildlife research center in wyoming in march 2013. ewes were sampled repeatedly over 16 mo. in april ... | 2017 | 27690193 |
| genome sequence of bibersteinia trehalosi strain y31 isolated from the pneumonic lung of a bighorn sheep. | here, we report the genome sequence for bibersteinia trehalosi strain y31, isolated from the lungs of a bighorn sheep (ovis canadensis) that had succumbed to pneumonia, which exhibits proximity-dependent inhibition (pdi) of mannheimia haemolytica the sequence will be used to understand the mechanism of pdi for these organisms. | 2016 | 27445392 |
| fusobacterium necrophorum in north american bighorn sheep ( ovis canadensis ) pneumonia. | fusobacterium necrophorum has been detected in pneumonic bighorn sheep (bhs; ovis canadensis ) lungs, in addition to the aerobic respiratory pathogens mannheimia haemolytica , bibersteinia trehalosi , pasteurella multocida , and mycoplasma ovipneumoniae . similar to m. haemolytica , f. necrophorum produces a leukotoxin. leukotoxin-induced lysis and degranulation of polymorphonuclear leukocytes (pmns) and macrophages are responsible for acute inflammation and lung tissue damage characteristic of ... | 2016 | 27224212 |
| epizootic pneumonia of bighorn sheep following experimental exposure to mycoplasma ovipneumoniae. | bronchopneumonia is a population limiting disease of bighorn sheep (ovis canadensis). the cause of this disease has been a subject of debate. leukotoxin expressing mannheimia haemolytica and bibersteinia trehalosi produce acute pneumonia after experimental challenge but are infrequently isolated from animals in natural outbreaks. mycoplasma ovipneumoniae, epidemiologically implicated in naturally occurring outbreaks, has received little experimental evaluation as a primary agent of bighorn sheep ... | 2014 | 25302992 |
| growth of mannheimia haemolytica: inhibitory agents and putative mechanism of inhibition. | leukotoxin-producing mannheimia haemolytica consistently causes fatal pneumonia in bighorn sheep (bhs) under experimental conditions. surprisingly, by culture methods, it has been isolated from pneumonic bhs lungs less frequently than other bacteria. however, in one study pcr assays detected m. haemolytica from over 70% of the pneumonic lung samples that were negative for this organism by culture, suggesting that the growth of m. haemolytica is inhibited by other bacteria. previously, we have sh ... | 2014 | 25246231 |
| bighorn sheep × domestic sheep hybrids survive mannheimia haemolytica challenge in the absence of vaccination. | bighorn sheep (bhs, ovis canadensis) are much more susceptible than domestic sheep (ds, ovis aries) to pneumonia caused by leukotoxin (lkt)-producing members of the family pasteurellaceae, particularly mannheimia haemolytica and bibersteinia trehalosi. leukotoxin is widely accepted as the critical virulence factor of these bacteria since lkt-negative mutants do not cause death of bhs. typically, ds carry lkt-positive m. haemolytica and/or b. trehalosi as commensal bacteria in their nasopharynx. ... | 2014 | 24629771 |
| pcr assay detects mannheimia haemolytica in culture-negative pneumonic lung tissues of bighorn sheep (ovis canadensis) from outbreaks in the western usa, 2009-2010. | mannheimia haemolytica consistently causes severe bronchopneumonia and rapid death of bighorn sheep (ovis canadensis) under experimental conditions. however, bibersteinia trehalosi and pasteurella multocida have been isolated from pneumonic bighorn lung tissues more frequently than m. haemolytica by culture-based methods. we hypothesized that assays more sensitive than culture would detect m. haemolytica in pneumonic lung tissues more accurately. therefore, our first objective was to develop a p ... | 2014 | 24171569 |
| phylogenetic and epidemiologic relationships among pasteurellaceae from colorado bighorn sheep herds. | we used 16s rrna sequencing and leukotoxin gene (lkta) screening via pcr assay to clarify phylogenetic and epidemiologic relationships among pasteurellaceae isolated from bighorn sheep (ovis canadensis). only six of 21 bighorn isolates identified as "mannheimia haemolytica" in original laboratory reports appeared to be isolates of m. haemolytica sensu stricto based on 16s rrna sequence comparisons; the remainder grouped with m. glucosida (n=8) or m. ruminalis (n=7). similarly, 16s rrna sequence ... | 2013 | 23778616 |
| role of bibersteinia trehalosi, respiratory syncytial virus, and parainfluenza-3 virus in bighorn sheep pneumonia. | pneumonic bighorn sheep (bhs) have been found to be culture- and/or sero-positive for bibersteinia trehalosi, respiratory syncytial virus (rsv), and parainfluenza-3 virus (pi-3). the objective of this study was to determine whether these pathogens can cause fatal pneumonia in bhs. in the first study, two groups of four bhs each were intra-tracheally administered with leukotoxin-positive (group i) or leukotoxin-negative (group ii) b. trehalosi. all four animals in group i developed severe pneumon ... | 2013 | 23025980 |
| proximity-dependent inhibition of growth of mannheimia haemolytica by pasteurella multocida. | mannheimia haemolytica, pasteurella multocida, and bibersteinia trehalosi have been identified in the lungs of pneumonic bighorn sheep (bhs; ovis canadensis). of these pathogens, m. haemolytica has been shown to consistently cause fatal pneumonia in bhs under experimental conditions. however, m. haemolytica has been isolated by culture less frequently than the other bacteria. we hypothesized that the growth of m. haemolytica is inhibited by other bacteria in the lungs of bhs. the objective of th ... | 2012 | 22798357 |
| pasteurellaceae isolated from bighorn sheep (ovis canadensis) from idaho, oregon, and wyoming. | to elucidate the species and biovariants of pasteurellaceae isolated from clinically normal bighorn sheep (ovis canadensis) or bighorn sheep with evidence of respiratory disease. | 2012 | 22738054 |
| causes of pneumonia epizootics among bighorn sheep, western united states, 2008-2010. | epizootic pneumonia of bighorn sheep is a devastating disease of uncertain etiology. to help clarify the etiology, we used culture and culture-independent methods to compare the prevalence of the bacterial respiratory pathogens mannheimia haemolytica, bibersteinia trehalosi, pasteurella multocida, and mycoplasma ovipneumoniae in lung tissue from 44 bighorn sheep from herds affected by 8 outbreaks in the western united states. m. ovipneumoniae, the only agent detected at significantly higher prev ... | 2012 | 22377321 |
| immunization of bighorn sheep against mannheimia haemolytica with a bovine herpesvirus 1-vectored vaccine. | mannheimia haemolytica is an important pathogen of pneumonia in bighorn sheep (bhs), consistently causing 100% mortality under experimental conditions. leukotoxin is the critical virulence factor of m. haemolytica. in a 'proof of concept' study, a vaccine containing leukotoxin and surface antigens of m. haemolytica induced 100% protection in bhs, but required multiple booster doses. vaccination of wildlife is difficult. bhs, however, can be vaccinated at the time of transplantation, but administ ... | 2017 | 28228321 |
| evidence of bovine viral diarrhea virus infection in three species of sympatric wild ungulates in nevada: life history strategies may maintain endemic infections in wild populations. | evidence for bovine viral diarrhea virus (bvdv) infection was detected in 2009-2010 while investigating a pneumonia die-off in rocky mountain bighorn sheep (ovis canadensis, canadensis), and sympatric mountain goats (oreamnos americanum) in adjacent mountain ranges in elko county, nevada. seroprevalence to bvdv-1 was 81% (n = 32) in the bighorns and 100% (n = 3) in the mountain goats. serosurveillance from 2011 to 2015 of surviving bighorns and mountain goats as well as sympatric mule deer (odoc ... | 2016 | 27014215 |
| clinical, culture, serology, and histopathology outcomes of bighorn sheep experimentally infected with brucella ovis. | disease caused by brucella ovis has not been previously reported in bighorn sheep (bhs; ovis canadensis canadensis). antibodies to b. ovis, however, are occasionally detected in free-ranging bhs, and this has been a concern for managers involved in translocation programs. to investigate the pathogenesis of b. ovis infection in this species, 20 bhs (10 male, 10 female) were inoculated intraconjunctivally (ic) with 5.4 × 10(8) colony forming units (cfu) b. ovis. six bhs (three male, three female) ... | 2013 | 24502717 |
| in vitro prion protein conversion suggests risk of bighorn sheep (ovis canadensis) to transmissible spongiform encephalopathies. | transmissible spongiform encephalopathies (tses) affect both domestic sheep (scrapie) and captive and free-ranging cervids (chronic wasting disease; cwd). the geographical range of bighorn sheep (ovis canadensis; bhs) overlaps with states or provinces that have contained scrapie-positive sheep or goats and areas with present epizootics of cwd in cervids. no tses have been documented in bhs, but the susceptibility of this species to tses remains unknown. | 2013 | 23938169 |
| histophilosis as a natural disease. | histophilus somni is responsible for sporadic disease worldwide in cattle and, to a lesser extent, in small ruminants, bighorn sheep (ovis canadensis), and north american bison (bison bison). the importance of h. somni diseases can be attributed to improved clinical and laboratory recognition, combined with the growth in intensive management practices for cattle. although outbreaks of bovine histophilosis can occur year-round, in northern and southern hemispheres, it is most frequent in late fal ... | 2016 | 26847357 |
| differential susceptibility of bighorn sheep (ovis canadensis) and domestic sheep (ovis aries) neutrophils to mannheimia haemolytica leukotoxin is not due to differential expression of cell surface cd18. | bighorn sheep ( ovis canadensis ) are more susceptible to pneumonia caused by mannheimia haemolytica than are domestic sheep ( ovis aries ). leukotoxin produced by m. haemolytica is the principal virulence factor involved in pneumonia pathogenesis. although leukotoxin is cytolytic to all subsets of ruminant leukocytes, neutrophils are the most susceptible subset. bighorn sheep neutrophils are 4- to 8-fold more susceptible to leukotoxin-induced cytolysis than are domestic sheep neutrophils. we hy ... | 2017 | 28323564 |
| a chimeric protein comprising the immunogenic domains of mannheimia haemolytica leukotoxin and outer membrane protein plpe induces antibodies against leukotoxin and plpe. | mannheimia haemolytica is a very important pathogen of pneumonia in ruminants. bighorn sheep (bhs, ovis canadensis) are highly susceptible to m. haemolytica-caused pneumonia which has significantly contributed to the drastic decline of bighorn sheep population in north america. pneumonia outbreaks in wild bhs can cause mortality as high as 90%. leukotoxin is the critical virulence factor of m. haemolytica. in a 'proof of concept' study, an experimental vaccine containing leukotoxin and surface a ... | 2016 | 27269790 |
| bighorn sheep pneumonia: sorting out the cause of a polymicrobial disease. | pneumonia of bighorn sheep (ovis canadensis) is a dramatic disease of high morbidity and mortality first described more than 80 years ago. the etiology of the disease has been debated since its initial discovery, and at various times lungworms, mannheimia haemolytica and other pasteurellaceae, and mycoplasma ovipneumoniae have been proposed as primary causal agents. a multi-factorial "respiratory disease complex" has also been proposed as confirmation of causation has eluded investigators. in th ... | 2013 | 23253148 |
| mhc class ii dr allelic diversity in bighorn sheep. | we hypothesized that decreased diversity and/or unique polymorphisms in mhc class ii alleles of bighorn sheep (bhs, ovis canadensis) are responsible for lower titer of antibodies against mannheimia haemolytica leukotoxin, in comparison to domestic sheep (ds, ovis aries). to test this hypothesis, dra and drb transcripts from 24 captive bhs (ovca-dra and ovca-drb) were sequenced. based on exon 2 (β1 domain) sequences, eight different ovca-drb cdna sequences were identified in bhs. six of them were ... | 2012 | 22750296 |
| contact and contagion: bighorn sheep demographic states vary in probability of transmission given contact. | 1.understanding both contact and probability of transmission given contact are key to managing wildlife disease. however, wildlife disease research tends to focus on contact heterogeneity, in part because probability of transmission given contact is notoriously difficult to measure. here we present a first step toward empirically investigating probability of transmission given contact in free-ranging wildlife. 2.we used measured contact networks to test whether bighorn sheep demographic states v ... | 2017 | 28317104 |
| role of carriers in the transmission of pneumonia in bighorn sheep (ovis canadensis). | in the absence of livestock contact, recurring lamb mortality in bighorn sheep (ovis canadensis) populations previously exposed to pneumonia indicates the likely presence of carriers of pneumonia-causing pathogens, and possibly inadequate maternally derived immunity. to investigate this problem we commingled naïve, pregnant ewes (n=3) with previously exposed rams (n=2). post-commingling, all ewes and lambs born to them acquired pneumonia-causing pathogens (leukotoxin-producing pasteurellaceae an ... | 2016 | 27185269 |
| blood values of captive beira antelope (dorcatragus megalotis) prior to and during an outbreak of fibrinous pleuropneumonia syndrome (fpps). | currently the only captive population of beira antelope (dorcatragus megalotis) is held at the al wabra wildlife preservation, qatar. an outbreak of a severe respiratory disease--fibrinous pleuropneumonia syndrome, most likely caused by mycoplasma ovipneumoniae--led to a marked population decline. reactive systemic inflammatory (aa) amyloidosis was noted as a chronic manifestation of the disease. blood samples had been collected for biochemistry and hematology baseline values prior to the outbre ... | 2014 | 25632657 |
| bighorn sheep (ovis canadensis) sinus tumors are associated with coinfections by potentially pathogenic bacteria in the upper respiratory tract. | bighorn sheep (ovis canadensis) sinus tumors are hyperplastic to neoplastic, predominantly stromal masses of the paranasal sinuses that expand the sinus lining and obstruct the sinus cavities. obstruction of the sinus cavities and disruption of normal sinus lining anatomy may interfere with clearance of bacterial pathogens from the upper respiratory tract. to examine this possibility, we explored whether the presence of sinus tumor features (tumor score) affected the likelihood of detecting pote ... | 2015 | 25375938 |
| detection of mycoplasma ovipneumoniae and m. arginini in bighorn sheep using enrichment culture coupled with genus- and species-specific polymerase chain reaction. | mycoplasma species are of interest as possible primary pathogens in the pneumonia complex of bighorn sheep (ovis canadensis). previous investigations have not commonly detected low frequencies of mycoplasma spp. from free-ranging bighorn sheep, possibly due to the fastidious and slow growth of these organisms. we developed a culture protocol that employed an average initial 3-day enrichment culture in liquid hayflick broth in a co(2)-enhanced atmosphere. the broth was plated to solid hayflick me ... | 2012 | 22493120 |
| sheep-associated malignant catarrhal fever-like skin disease in a free-ranging bighorn sheep ( ovis canadensis ), alberta, canada. | malignant catarrhal fever-like clinical disease was diagnosed in a free-ranging bighorn sheep ( ovis canadensis ) from alberta, canada, in june 2015. antemortem and gross pathology findings included muscle atrophy, marked weight loss, and bilaterally symmetric alopecia with hyperpigmentation and crusting over the face, medial surfaces of the pinnae, dorsal trunk, distal limbs, perineal area, and tail. histologically, the skin lesions were characterized by granulomatous mural folliculitis with nu ... | 2017 | 27749194 |
| seasonal foraging ecology of non-migratory cougars in a system with migrating prey. | we tested for seasonal differences in cougar (puma concolor) foraging behaviors in the southern yellowstone ecosystem, a multi-prey system in which ungulate prey migrate, and cougars do not. we recorded 411 winter prey and 239 summer prey killed by 28 female and 10 male cougars, and an additional 37 prey items by unmarked cougars. deer composed 42.4% of summer cougar diets but only 7.2% of winter diets. males and females, however, selected different proportions of different prey; male cougars se ... | 2013 | 24349498 |
| large herbivores surf waves of green-up during spring. | the green wave hypothesis (gwh) states that migrating animals should track or 'surf' high-quality forage at the leading edge of spring green-up. to index such high-quality forage, recent work proposed the instantaneous rate of green-up (irg), i.e. rate of change in the normalized difference vegetation index over time. despite this important advancement, no study has tested the assumption that herbivores select habitat patches at peak irg. we evaluated this assumption using step selection functio ... | 2016 | 27335416 |
| beta-globin gene evolution in the ruminants: evidence for an ancient origin of sheep haplotype b. | domestic sheep (ovis aries) can be divided into two groups with significantly different responses to hypoxic environments, determined by two allelic beta-globin haplotypes. haplotype a is very similar to the goat beta-globin locus, whereas haplotype b has a deletion spanning four globin genes, including beta-c globin, which encodes a globin with high oxygen affinity. we surveyed the beta-globin locus using resequencing data from 70 domestic sheep from 42 worldwide breeds and three ovis canadensi ... | 2015 | 26096044 |
| evaluating apparent competition in limiting the recovery of an endangered ungulate. | predation can disproportionately affect endangered prey populations when generalist predators are numerically linked to more abundant primary prey. apparent competition, the term for this phenomenon, has been increasingly implicated in the declines of endangered prey populations. we examined the potential for apparent competition to limit the recovery of sierra nevada bighorn sheep (ovis canadensis sierrae), an endangered subspecies under the us endangered species act. using a combination of loc ... | 2013 | 22791131 |
| effect of vaccination against pneumonia on the survival of bighorn sheep (ovis canadensis) commingled with carrier animals. | leukotoxin producing (lkt+) members of pasteurellaceae, particularly mannheimia haemolytica and bibersteinia trehalosi are important pathogens of pneumonia in bighorn sheep (bhs; ovis canadensis), causing fatal disease. predisposing or concurrent infection with mycoplasma ovipneumoniae enhances the severity of the disease, resulting in increased morbidity and mortality. several studies have investigated the effectiveness of vaccines against lkt+ members of pasteurellaceae in preventing fatal pne ... | 2017 | 28619167 |
| myocardial necrosis associated with clostridium novyi infection in a bighorn sheep ( ovis canadensis ). | we describe a case of myocardial emphysema and necrosis in a bighorn sheep ( ovis canadensis ), associated with infection by clostridium novyi , diagnosed through necropsy, histopathology, and fluorescent antibody testing. we documented rapid onset of disease in an apparently healthy wild sheep and discuss our findings in the context of reported clostridial infections in humans, domestic animals, and wildlife. | 2017 | 28406756 |
| detection of bacterial-reactive natural igm antibodies in desert bighorn sheep populations. | ecoimmunology is a burgeoning field of ecology which studies immune responses in wildlife by utilizing general immune assays such as the detection of natural antibody. unlike adaptive antibodies, natural antibodies are important in innate immune responses and often recognized conserved epitopes present in pathogens. here, we describe a procedure for measuring natural antibodies reactive to bacterial antigens that may be applicable to a variety of organisms. igm from desert bighorn sheep plasma s ... | 2017 | 28662203 |
| assessing respiratory pathogen communities in bighorn sheep populations: sampling realities, challenges, and improvements. | respiratory disease has been a persistent problem for the recovery of bighorn sheep (ovis canadensis), but has uncertain etiology. the disease has been attributed to several bacterial pathogens including mycoplasma ovipneumoniae and pasteurellaceae pathogens belonging to the mannheimia, bibersteinia, and pasteurella genera. we estimated detection probability for these pathogens using protocols with diagnostic tests offered by a fee-for-service laboratory and not offered by a fee-for-service labo ... | 2017 | 28708832 |
| exposure of bighorn sheep to domestic goats colonized with mycoplasma ovipneumoniae induces sub-lethal pneumonia. | bronchopneumonia is a population limiting disease of bighorn sheep (ovis canadensis) that has been associated with contact with domestic caprinae. the disease is polymicrobial but is initiated by mycoplasma ovipneumoniae, which is commonly carried by both domestic sheep (o. aries) and goats (capra aegagrus hircus). however, while previous bighorn sheep comingling studies with domestic sheep have resulted in nearly 100% pneumonia mortality, only sporadic occurrence of fatal pneumonia was reported ... | 2017 | 28591169 |
| efficacy of a portable oxygen concentrator with pulsed delivery for treatment of hypoxemia during anesthesia of wildlife. | portable battery-driven oxygen concentrators provide an alternative to the use of oxygen cylinders for treatment of hypoxemia during field anesthesia. the aim of this study was to evaluate the use of the evergo portable oxygen concentrator (respironics, murrysville, pennsylvania 15668, usa) with pulse-dose delivery for improvement of arterial oxygenation during anesthesia of wildlife. this concentrator delivers oxygen in a pulsed flow with pulse volumes from 12 to 70 ml, up to a maximum capacity ... | 2012 | 22448511 |
| molecular surveillance for bartonella, borrelia, and rickettsia species in ticks from desert bighorn sheep ( ovis canadensis) and mule deer ( odocoileus hemionus) in southern california, usa. | : ticks (acari: ixodidae) were collected from 44 desert bighorn sheep ( ovis canadensis) and 10 mule deer ( odocoileus hemionus) in southern california, us during health inspections in 2015-16. specimens were identified and screened by pcr analysis to determine the presence and prevalence of bartonella, borrelia, and rickettsia species in ticks associated with these wild ruminants. none of the 60 dermacentor hunteri and 15 dermacentor albipictus ticks tested yielded positive pcr results. additi ... | 2018 | 28977771 |
| correction: exposure of bighorn sheep to domestic goats colonized with mycoplasma ovipneumoniae induces sub-lethal pneumonia. | [this corrects the article doi: 10.1371/journal.pone.0178707.]. | 2018 | 29364974 |
| potential disease agents in domestic goats and relevance to bighorn sheep (ovis canadensis) management. | domestic goats are raised for meat, milk and hair production, in herds for rangeland weed control, and as pack animals. domestic sheep, goats and wild bighorn sheep are all susceptible to a multifactorial pneumonia. we sampled 43 herd goats from 7 herds and 48 pack goats from 11 herds for viral and bacterial serology, parasitology, and pasteurellaceae microbiology. the goats in this study were in generally good health, although most goats did harbor various pathogens and parasites including seve ... | 2017 | 28282407 |
| beyond mice and men: environmental change, immunity and infections in wild ungulates. | in the face of rapid environmental change, anticipating shifts in microparasite and macroparasite dynamics, including emergence events, is an enormous challenge. we argue that immunological studies in natural populations are pivotal to meeting this challenge: many components of environmental change--shifts in biotic assemblages, altered climate patterns and reduced environmental predictability--may affect host immunity. we suggest that wild ungulates can serve as model systems aiding the discove ... | 2015 | 25354672 |
| snp discovery in candidate adaptive genes using exon capture in a free-ranging alpine ungulate. | identification of genes underlying genomic signatures of natural selection is key to understanding adaptation to local conditions. we used targeted resequencing to identify snp markers in 5321 candidate adaptive genes associated with known immunological, metabolic and growth functions in ovids and other ungulates. we selectively targeted 8161 exons in protein-coding and nearby 5' and 3' untranslated regions of chosen candidate genes. targeted sequences were taken from bighorn sheep (ovis canaden ... | 2016 | 27327375 |
| genome-wide set of snps reveals evidence for two glacial refugia and admixture from postglacial recolonization in an alpine ungulate. | past glaciation events have played a major role in shaping the genetic diversity and distribution of wild sheep in north america. the advancement of glaciers can isolate populations in ice-free refugia, where they can survive until the recession of ice sheets. the major beringian refugium is thought to have held thinhorn sheep (ovis dalli) populations during times of glacial advance. while isolation in the major refugium can account for much of the genetic and morphological diversity seen in ext ... | 2016 | 27272944 |
| differences in leukocyte differentiation molecule abundances on domestic sheep (ovis aries) and bighorn sheep (ovis canadensis) neutrophils identified by flow cytometry. | although both domestic sheep (ds) and bighorn sheep (bhs) are affected by similar respiratory bacterial pathogens, experimental and field data indicate bhs are more susceptible to pneumonia. cross-reactive monoclonal antibodies (mabs) for use in flow cytometry (fc) are valuable reagents for interspecies comparative immune system analyses. this study describes cross-reactive mabs that recognize leukocyte differentiation molecules (ldms) and major histocompatibility complex antigens on ds and bhs ... | 2016 | 27260809 |
| experimental transmission of bighorn sheep sinus tumors to bighorn sheep (ovis canadensis canadensis) and domestic sheep. | bighorn sheep sinus tumors are a recently described disease affecting the paranasal sinuses of rocky mountain bighorn sheep (ovis canadensis canadensis). several features of this disease suggest an infectious cause, although a specific etiologic agent has not been identified. to test the hypothesis that bighorn sheep sinus tumors are caused by an infectious agent, we inoculated 4 bighorn sheep lambs and 4 domestic sheep lambs intranasally with a cell-free filtrate derived from a naturally occurr ... | 2016 | 27020536 |
| phenotypic and molecular characterization of intrauterine fetal growth restriction in interspecies sheep pregnancy. | interspecies pregnancies between closely related species are usually performed in livestock to obtain improved and enriched offspring. indeed, different hybrids have been obtained for research purposes since many years ago, and the maternal-fetal interactions have been studied as a possible strategy for species preservation. the aim of this study was to characterize by physiological and molecular approaches the interspecies pregnancy between bighorn sheep () and domestic sheep (). hybrids were o ... | 2015 | 26523562 |
| a spatial risk assessment of bighorn sheep extirpation by grazing domestic sheep on public lands. | bighorn sheep currently occupy just 30% of their historic distribution, and persist in populations less than 5% as abundant overall as their early 19th century counterparts. present-day recovery of bighorn sheep populations is in large part limited by periodic outbreaks of respiratory disease, which can be transmitted to bighorn sheep via contact with domestic sheep grazing in their vicinity. in order to assess the viability of bighorn sheep populations on the payette national forest (pnf) under ... | 2014 | 24507886 |
| the complete mitochondrial genome sequence analysis of tibetan argali (ovis ammon hodgsoni): implications of tibetan argali and gansu argali as the same subspecies. | the genus ovis (bovidae, artiodactyla) includes six species, i.e. ovis ammon, ovis aries, ovis canadensis, ovis dalli, ovis nivicola and ovis vignei. based on morphology, geographical location, habitat, etc., the species o. ammon is divided into nine subspecies. the near threatened tibetan argali is distributed across the tibetan plateau and its peripheral mountains, and believed to be one of the o. ammon subspecies (o. a. hodgsoni). however, considering its morphological features and distributi ... | 2013 | 23542075 |
| reference intervals for mineral concentrations in whole blood and serum of bighorn sheep (ovis canadensis) in california. | whole blood and serum mineral concentrations were measured in diverse bighorn sheep (ovis canadensis) metapopulations in california, and 90% reference intervals were determined. while there were some statistical differences between median concentrations among the different metapopulations, detected values were generally in good agreement with concentrations reported for other bighorn sheep populations and with reference ranges widely accepted for domestic sheep (ovis aries). although median whol ... | 2012 | 22529120 |
| drivers and demographic consequences of seasonal mass changes in an alpine ungulate. | we know little about the determinants and demographic consequences of the marked seasonal mass changes exhibited by many northern and alpine mammals. we analysed 43 years of data on individual winter mass loss (the difference between mass in early june and mass in mid-september the previous year) and summer mass gain (the difference between mass in mid-september and in early june of the same year) in adult bighorn sheep (ovis canadensis). we calculated relative seasonal mass change as a proporti ... | 2018 | 29336476 |
| direct and indirect effects of early-life environment on lifetime fitness of bighorn ewes. | cohort effects, when a common environment affects long-term performance, can have a major impact on population dynamics. very few studies of wild animals have obtained the necessary data to study the mechanisms leading to cohort effects. we exploited 42 years of individual-based data on bighorn sheep to test for causal links between birth density, body mass, age at first reproduction (afr), longevity and lifetime reproductive success (lrs) using path analysis. specifically, we investigated wheth ... | 2018 | 29321295 |
| corynebacterium pseudotuberculosis and copper deficiency in a male rocky mountain bighorn sheep ( ovis canadensis canadensis) in utah, usa. | : in 2015, an emaciated rocky mountain bighorn ( ovis canadensis) ram was submitted to the utah veterinary diagnostic laboratory for necropsy. there were numerous thick-walled abscesses subcutaneously and internally, and corynebacterium pseudotuberculosis was isolated in pure culture. in addition, the ram was severely copper deficient, with a liver copper concentration of 1.6 mg/kg. | 2018 | 28977770 |
| hierarchical structure and compressive deformation mechanisms of bighorn sheep (ovis canadensis) horn. | bighorn sheep (ovis canadensis) rams hurl themselves at each other at speeds of ∼9 m/s (20 mph) to fight for dominance and mating rights. this necessitates impact resistance and energy absorption mechanisms, which stem from material-structure components in horns. in this study, the material hierarchical structure as well as correlations between the structure and mechanical properties are investigated. the major microstructural elements of horns are found as tubules and cell lamellae, which are o ... | 2017 | 28974475 |
| age-specific infectious period shapes dynamics of pneumonia in bighorn sheep. | superspreading, the phenomenon where a small proportion of individuals contribute disproportionately to new infections, has profound effects on disease dynamics. superspreading can arise through variation in contacts, infectiousness or infectious periods. the latter has received little attention, yet it drives the dynamics of many diseases of critical public health, livestock health and conservation concern. here, we present rare evidence of variation in infectious periods underlying a superspre ... | 2017 | 28871636 |
| fluctuating effects of genetic and plastic changes in body mass on population dynamics in a large herbivore. | recent studies suggest that evolutionary changes can occur on a contemporary time scale. hence, evolution can influence ecology and vice-versa. to understand the importance of eco-evolutionary dynamics in population dynamics, we must quantify the relative contribution of ecological and evolutionary changes to population growth and other ecological processes. to date, however, most eco-evolutionary dynamics studies have not partitioned the relative contribution of plastic and evolutionary changes ... | 2017 | 28646625 |
| simulating the spread of selection-driven genotypes using landscape resistance models for desert bighorn sheep. | landscape genetic studies based on neutral genetic markers have contributed to our understanding of the influence of landscape composition and configuration on gene flow and genetic variation. however, the potential for species to adapt to changing landscapes will depend on how natural selection influences adaptive genetic variation. we demonstrate how landscape resistance models can be combined with genetic simulations incorporating natural selection to explore how the spread of adaptive variat ... | 2017 | 28464013 |
| long-term fitness consequences of early environment in a long-lived ungulate. | cohort effects can be a major source of heterogeneity and play an important role in population dynamics. silver-spoon effects, when environmental quality at birth improves future performance regardless of the adult environment, can induce strong lagged responses on population growth. alternatively, the external predictive adaptive response (par) hypothesis predicts that organisms will adjust their developmental trajectory and physiology during early life in anticipation of expected adult conditi ... | 2017 | 28424347 |
| disease introduction is associated with a phase transition in bighorn sheep demographics. | ecological theory suggests that pathogens are capable of regulating or limiting host population dynamics, and this relationship has been empirically established in several settings. however, although studies of childhood diseases were integral to the development of disease ecology, few studies show population limitation by a disease affecting juveniles. here, we present empirical evidence that disease in lambs constrains population growth in bighorn sheep (ovis canadensis) based on 45 years of p ... | 2016 | 27859120 |
| moisture, anisotropy, stress state, and strain rate effects on bighorn sheep horn keratin mechanical properties. | this paper investigates the effects of moisture, anisotropy, stress state, and strain rate on the mechanical properties of the bighorn sheep (ovis canadensis) horn keratin. the horns consist of fibrous keratin tubules extending along the length of the horn and are contained within an amorphous keratin matrix. samples were tested in the rehydrated (35wt% water) and ambient dry (10wt% water) conditions along the longitudinal and radial directions under tension and compression. increased moisture c ... | 2017 | 27793720 |
| towards robust evolutionary inference with integral projection models. | integral projection models (ipms) are extremely flexible tools for ecological and evolutionary inference. ipms track the distribution of phenotype in populations through time, using functions describing phenotype-dependent development, inheritance, survival and fecundity. for evolutionary inference, two important features of any model are the ability to (i) characterize relationships among traits (including values of the same traits across ages) within individuals, and (ii) characterize similari ... | 2017 | 27783447 |
| comparison of two bacterial transport media for culture of tonsilar swabs from bighorn sheep ( ovis canadensis ) and mountain goats ( oreamnos americanus ). | duplicate tonsilar swabs were collected from 77 bighorn sheep ( ovis canadensis ) and 19 mountain goats ( oreamnos americanus ) in utah. swabs were refrigerated in bacterial transport medium or frozen in cryopreservation medium prior to bacteriologic culture. the cryopreservation medium yielded comparable or superior bacterial growth while permitting more flexibility in specimen shipment to the laboratory. | 2017 | 27669011 |
| horn and horn core trabecular bone of bighorn sheep rams absorbs impact energy and reduces brain cavity accelerations during high impact ramming of the skull. | bighorn sheep (ovis canadensis) routinely experience violent impacts to the head as part of intraspecific fighting. dynamic 3d finite element models of the skull and horns of a male bighorn sheep were developed to gain an understanding of the roles that the horn and bone materials and structure play in absorbing the impact that occurs during ramming. the geometry and volume mesh of the model were derived from ct scan images. the models included the horn, bony horn core, and bone of the skull. th ... | 2016 | 27544811 |
| maternal condition and previous reproduction interact to affect offspring sex in a wild mammal. | trivers and willard proposed that offspring sex ratio should vary with maternal condition when condition, meant as maternal capacity to care, has different fitness consequences for sons and daughters. in polygynous and dimorphic species, mothers in good condition should preferentially produce sons, whereas mothers in poor condition should produce more daughters. despite its logical appeal, support for this hypothesis has been inconsistent. sex-ratio variation may be influenced by additional fact ... | 2016 | 27512136 |
| an individual-based modelling approach to estimate landscape connectivity for bighorn sheep (ovis canadensis). | background. preserving connectivity, or the ability of a landscape to support species movement, is among the most commonly recommended strategies to reduce the negative effects of climate change and human land use development on species. connectivity analyses have traditionally used a corridor-based approach and rely heavily on least cost path modeling and circuit theory to delineate corridors. individual-based models are gaining popularity as a potentially more ecologically realistic method of ... | 2016 | 27168997 |
| demographic drivers of age-dependent sexual selection. | sexual selection has a critical role in evolution, and it is fundamental to identify what ecological factors drive its variation. disentangling the ecological correlates of sexual selection over the long term, however, is challenging and has rarely been done in nature. we sought to assess how demographic changes influenced the intensity, direction and form of sexual selection and whether selective pressures varied with age. we tested whether breeder sex ratio, number of competitors and age struc ... | 2016 | 27090379 |
| paternal reproductive success drives sex allocation in a wild mammal. | parents should bias sex allocation toward offspring of the sex most likely to provide higher fitness returns. trivers and willard proposed that for polygynous mammals, females should adjust sex-ratio at conception or bias allocation of resources toward the most profitable sex, according to their own body condition. however, the possibility that mammalian fathers may influence sex allocation has seldom been considered. here, we show that the probability of having a son increased from 0.31 to 0.60 ... | 2016 | 26792564 |
| whole-genome resequencing uncovers molecular signatures of natural and sexual selection in wild bighorn sheep. | the identification of genes influencing fitness is central to our understanding of the genetic basis of adaptation and how it shapes phenotypic variation in wild populations. here, we used whole-genome resequencing of wild rocky mountain bighorn sheep (ovis canadensis) to >50-fold coverage to identify 2.8 million single nucleotide polymorphisms (snps) and genomic regions bearing signatures of directional selection (i.e. selective sweeps). a comparison of snp diversity between the x chromosome an ... | 2015 | 26454263 |
| evaluating distributional shifts in home range estimates. | a variety of methods are commonly used to quantify animal home ranges using location data acquired with telemetry. high-volume location data from global positioning system (gps) technology provide researchers the opportunity to identify various intensities of use within home ranges, typically quantified through utilization distributions (uds). however, the wide range of variability evident within uds constructed with modern home range estimators is often overlooked or ignored during home range c ... | 2015 | 26445648 |
| psoroptes infestation and treatment in an isolated population of bighorn sheep (ovis canadensis). | the authors captured bighorn sheep (ovis canadensis) comprising a small population in the san bernardino mountains of california and evaluated the degree of infestation by mites of the genus psoroptes for each individual. the animals were treated with two novel methods: amitraz-impregnated collars and cyfluthrin-impregnated ear tags and recaptured the following year to evaluate the effect of treatment. the authors compared data on degree of infestation for animals recaptured in the posttreatment ... | 2015 | 26352952 |
| comparison of modified flotac and baermann techniques for quantifying lungworm larvae in free-ranging bighorn sheep (ovis canadensis) feces, montana, usa. | lungworms are important parasites of wildlife and host infection status is often evaluated using coprologic techniques, most commonly the baermann method. recently, the flotac® has emerged as a new tool for diagnosing lungworm infections, and methodologic comparison studies in domestic species suggest that this method outperforms many other established techniques. we compared a modified flotac with the beaker-modified (bm)-baermann to evaluate the relative performance of the two techniques for c ... | 2015 | 26267464 |