Publications

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a review of some aspects of vitamin e-selenium responsive diseases with a note on their possible incidence in alberta. 1976769935
composition of the rumen ciliate population in experimental herds of cattle and sheep in lethbridge, alberta, western canada.rumen ciliate populations were surveyed in 11 holstein cattle and 6 sheep in lethbridge (alta., canada) to determine species distribution in this western canadian environment. a total of 28 ciliate species were identified in cattle and 17 in sheep. the average total number of ciliates per millilitre of rumen content was 6.9 x 10(4) in cattle and 1.9 x 10(5) in sheep. the average number of species per host was 20.5 in cattle and 13.8 in sheep. of the ciliate species detected, species of entodiniu ...19892504472
[nematodirinae (nematoda:trichostrongyloidea) of antilocapra and ovis in alberta, canada].in this first note, the trichostrongyloidea belonging to the nematodirinae parasites of ruminants from alberta are identified. new morphological data were given on nematodirella antilocaprae (price, 1927) parasite of antilocapra americana. nematodirus andersoni n. sp. is described from ovis canadensis. because of the deep indentation of the dorsal lobe, the species is similar to n. bioccai rossi, 1983 parasite of ovis aries in iran. however, it is different in the reduced number of cuticular rid ...19892624376
antigenic analysis of giardia duodenalis strains isolated in alberta.giardia duodenalis is a common intestinal parasite in most parts of the world. in canada it is associated with both endemic and epidemic infections that are often transmitted by the waterborne route. although g. duodenalis strains have been isolated from several animals, the role of other mammals in human infection is unclear. we have isolated and cultured g. duodenalis trophozoites from domestic and wild animals in alberta and compared them with a human isolate by protein gel electrophoresis an ...19863545410
differences in paralyzing ability and sites of attachment to cattle of rocky mountain wood ticks (acari: ixodidae) from three regions of western canada. 19853981550
diphtheria bacilli isolated in alberta in 1967 from the throat, nose, ears and skin. 19694980469
the incidence of caseous lymphadenitis in alberta sheep and assessment of impact by vaccination with commercial and experimental vaccines.in alberta, caseous lymphadenitis (cla) is one of the leading causes of lamb and mutton carcass condemnation. in this study, serologic results confirmed a high (50-94%) incidence of exposure to corynebacterium pseudotuberculosis, the causative agent of cla, in mature, unvaccinated sheep in southern alberta. to assess the efficacy and impact of vaccination with 2 commercial (glanvac-6 and case-vac) and 1 experimental (wc+ mdp-gdp) cla vaccines, a series of 3 field trials in 3249 ewes and lambs wa ...19989442938
seroprevalence of toxoplasma gondii in rocky mountain bighorn sheep (ovis canadensis).serum samples from 697 rocky mountain bighorn sheep (ovis canadensis) from north america were examined for antibodies to toxoplasma gondii by the modified agglutination test incorporating mercaptoethanol and formalin-fixed tachyzoites. antibodies to t. gondii were found in 25 of 697 (3.6%) sheep in titers of 1:25 (8 sheep), 1:50 (4 sheep), 1:100 (7 sheep), 1:200 (1 sheep), 1:400 (1 sheep), 1:800 (1 sheep), and 1:1,600 (3 sheep). this is the first record of t. gondii exposure in bighorn sheep.200010864265
the first canadian indigenous case of bovine spongiform encephalopathy (bse) has molecular characteristics for prion protein that are similar to those of bse in the united kingdom but differ from those of chronic wasting disease in captive elk and deer.brain tissue from a case of bovine spongiform encephalopathy (bse) from alberta was subjected to a western immunoblotting technique to ascertain the molecular profile of any disease-specific, abnormal prion protein, that is, prion protein that is protease-resistant (prp(res)). this technique can discriminate between isolates from bse, ovine scrapie, and sheep experimentally infected with bse. isolates of brain tissue from the bse case in alberta, 3 farmed elk with chronic wasting disease (cwd) f ...200415532881
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), ...200516108550
prevalence of maedi-visna infection in culled ewes in alberta.maedi-visna (mv) is a relatively common chronic infection of sheep in north america resulting in economic loss to the sheep industry. the objectives of this study were to: 1) measure the prevalence of mv infection in culled ewes in alberta, by histologic examination (lungs and udder) and serologic testing using an agar gel immunodiffusion (agid) test, 2) examine any geographic differences in its prevalence in the province, 3) evaluate the level of agreement between histopathologic examination an ...200616734372
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 ...200717683438
phosphogypsum capping depth affects revegetation and hydrology in western canada.phosphogypsum (pg), a byproduct of phosphate fertilizer manufacturing, is commonly stacked and capped with soil at decommissioning. shallow (0, 8, 15, and 30 cm) and thick (46 and 91 cm) sandy loam caps on a pg stack near fort saskatchewan, alberta, canada, were studied in relation to vegetation establishment and hydrologic properties. plant response was evaluated over two growing seasons for redtop ( l.), slender wheatgrass ( (link) malte ex h.f. lewis), tufted hairgrass ( (l.) p. beauv.), and ...201121712581
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 ...201222247368
restoration of foothills rough fescue grassland following pipeline disturbance in southwestern alberta.the effects of pipeline construction and reclamation techniques on the restoration of rough fescue plant communities following pipeline construction in southwestern alberta, canada were evaluated after 7-40 years. the pipeline construction right-of-way (row) sites varied from no recovery of rough fescue grassland to moderate recovery. the row sites had a higher proportion of introduced grasses and forbs, less topsoil, and poorer rangeland health than the adjacent undisturbed grassland. within th ...201020801578
antimicrobial use in the alberta sheep industry.information regarding antimicrobial use in sheep is scarce. in 2001, a scrapie surveillance program was initiated in alberta that also provided a mechanism for collecting other sheep health data including antimicrobial use information between april 2001 and april 2002. a major objective of this study was to describe antimicrobial use in the alberta sheep industry. this was done by obtaining qualitative antimicrobial use information from all flocks (n = 212) providing cull ewes to the program usi ...200818505202
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 ...200516050112
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 ...200515969737
listeria monocytogenes isolations in alberta 1951-1970. 19724622759
ovine chlamydial abortion in alberta. 19761260643
prenatal infection of the rocky mountain bighorn sheep (ovis c. canadensis) of alberta with the lungworm protostrongylus spp.first- and third-stage (infective) larvae of protostrongylus spp. were recovered from the livers of four fetuses of the rocky mountain bighorn sheep of alberta. this record suggests a more cosmopolitan distribution of prenatal infection with lungworms in bighorn sheep than suspected previously.1977916136
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 ...200616777749
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 ...200516475080
sarcocystis in wild ungulates in alberta.muscle samples from 557 wild ungulates in alberta, comprising seven species, were examined grossly and/or histologically for cysts of sarcocystis. sarcocystis was found in 100, 96, 94, 75, 75, 73, and 49% of the wapiti (cervus canadensis), moose (alces alces), bison (bison bison), mule deer (odocoileus hemionus), bighorn sheep (ovis canadensis), mountain goat (oreamnos americanus), and white-tailed deer (o. virginianus), respectively.19806780701
susceptibility of rocky mountain bighorn sheep and domestic sheep to pneumonia induced by bighorn and domestic livestock strains of pasteurella haemolytica.bighorn sheep were inoculated intratracheally with suspensions of nonhemolytic pasteurella haemolytica biotype t (10(12) organisms) unique to wild bighorns, with beta-hemolytic p. haemolytica biotype t (10(12) organisms) isolated from clinically normal domestic sheep or intradermally with half a dose of a cattle vaccine containing p. haemolytica biotype a (10(5) organisms). the bighorn strain caused lobar necrotizing bronchopneumonia whereas both domestic livestock strains precipitated fatal sep ...19883196974
predator-driven component allee effects in a wild ungulate.negative density dependence is an important driver of population dynamics of large vertebrates. allee effects (positive density dependence), however, can affect small populations. allee effects can be generated by predation and recent research has revealed potentially important indirect effects of predation on population dynamics. for wild populations, however, quantification of both allee effects and indirect effects of predation remains scarce. we monitored for 27 years a bighorn sheep (ovis c ...201121320261
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 ...200818443828
the effects of chlorinated municipal sewage and temperature on the abundance of bacteria in the sheep river, alberta.the intersite and temporal differences in the abundance of sessile and planktonic bacteria subjected to a chlorinated municipal sewage discharge and a thermal discharge were investigated in the sheep river, alberta, from january through december 1978. significantly higher densities of both sessile and planktonic cells generally occurred within the chlorinated effluent plume. higher numbers of sessile bacteria were also found below the thermal discharge, with maximum densities occurring in the la ...19836850419
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 ...200111903565
serological classification and virulence determination of dichelobacter nodosus isolated from alberta and british columbia sheep.ovine footrot is a contagious disease of sheep that occurs in temperature climates. it is caused by the strict anaerobe, dichelobacter nodosus. benign and virulent organisms are differentiated according to serotype and protease production. this study was conducted to identify the presence of virulent serotypes of d. nodosus in sheep flocks in alberta and british columbia. dichelobacter nodosus was detected in lame sheep from 11 of 15 (73%) flocks in alberta and in 4 of 5 (80%) british columbia f ...19989442937
prevalence and intensity of gastrointestinal nematodes in slaughter lambs from central alberta.two trichostronglyes, teladorsagia ostertagi and nematodiru helvetianus, accounted for > 99% of nematodes recovered from gastrointestinal tracts of 47 lambs pastured in central alberta during the summer of 2000. their prevalence and mean intensity increased from < 10% and < 50 worms/host, in late june, to > 80% and approximately 1000 worms/host, by mid-july, respectively.200212395759
zoonotic potential of giardiasis in domestic ruminants.this study was conducted to assess the prevalence and zoonotic potential of giardiasis in domestic ruminants. prevalence of infection was 17.7% in sheep and 10.4% in cattle and was significantly higher in lambs and calves (35.6% and 27.7%, respectively). naturally infected lambs released cysts intermittently for months. giardia trophozoites from sheep had typical claw hammer-shaped median bodies and were successfully cultured in tyi-s-33 medium, and cytosolic, cytoskeletal, and membrane fraction ...19902355197
sheep horns downsized by hunters' taste for trophies. 200314668829
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