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1.
PeerJ ; 12: e16946, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38426129

RESUMO

Due to their abundance and relative ease of genotyping, single nucleotide polymorphisms (SNPs) are a commonly used molecular marker for contemporary population genetic and genomic studies. A high-density and cost-effective way to type SNP loci is Allegro targeted genotyping (ATG), which is a form of targeted genotyping by sequencing developed and offered by Tecan genomics. One major drawback of this technology is the need for a reference genome and information on SNP loci when designing a SNP assay. However, for some non-model species genomic information from other closely related species can be used. Here we describe our process of developing an ATG assay to target 50,000 SNPs in Rocky Mountain bighorn sheep, using a reference genome from domestic sheep and SNP resources from prior bighorn sheep studies. We successfully developed a high accuracy, high-density, and relatively low-cost SNP assay for genotyping Rocky Mountain bighorn sheep that genotyped ~45,000 SNP loci. These loci were relatively evenly distributed throughout the genome. Furthermore, the assay produced genotypes at tens of thousands of SNP loci when tested on other mountain sheep species and subspecies.


Assuntos
Polimorfismo de Nucleotídeo Único , Carneiro da Montanha , Animais , Ovinos/genética , Polimorfismo de Nucleotídeo Único/genética , Carneiro da Montanha/genética , Genoma , Genótipo , Genômica
2.
Acta Biomater ; 174: 258-268, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38072223

RESUMO

The horns of bighorn sheep rams are permanent cranial appendages used for high energy head-to-head impacts during interspecific combat. The horns attach to the underlying bony horncore by a layer of interfacial tissue that facilitates load transfer between the impacted horn and underlying horncore, which has been shown to absorb substantial energy during head impact. However, the morphology and mechanical properties of the interfacial tissue were previously unknown. Histomorphometry was used to quantify the interfacial tissue composition and morphology and lap-shear testing was used to quantify its mechanical properties. Histological analyses revealed the interfacial tissue is a complex network of collagen and keratin fibers, with collagen being the most abundant protein. Sharpey's fibers provide strong attachment between the interfacial tissue and horncore bone. The inner horn surface displayed microscopic porosity and branching digitations which increased the contact surface with the interfacial tissue by approximately 3-fold. Horn-horncore samples tested by lap-shear loading failed primarily at the horn surface, and the interfacial tissue displayed non-linear strain hardening behavior similar to other soft tissues. The elastic properties of the interfacial tissue (i.e., low- and high-strain shear moduli) were comparable to previously measured values for the equine laminar junction. The interfacial tissue contact surface was positively correlated with the interfacial tissue shear strength (1.23 ± 0.21 MPa), high-strain shear modulus (4.5 ± 0.7 MPa), and strain energy density (0.38 ± 0.07 MJ/m3). STATEMENT OF SIGNIFICANCE: The bony horncore in bighorn sheep rams absorbs energy to reduce brain cavity accelerations and mitigate brain injury during head butting. The interfacial zone between the horn and horncore transfers energy from the impacted horn to the energy absorbing horncore but has been largely neglected in previous models of bighorn sheep ramming since interfacial tissue properties were previously unknown. This study quantified the morphology and mechanical properties of the horn-horncore interfacial tissue to better understand structure-property relationships that contribute to energy transfer during ramming. Results from this study will improve models of bighorn sheep ramming used to study mechanisms of brain injury mitigation and may inspire novel materials and structures for brain injury prevention in humans.


Assuntos
Lesões Encefálicas , Cornos , Carneiro da Montanha , Humanos , Animais , Masculino , Cavalos , Ovinos , Cornos/anatomia & histologia , Crânio , Colágeno/metabolismo
3.
Can Vet J ; 64(12): 1114-1118, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38046428

RESUMO

Domestic sheep (Ovis aries) can carry the bacterium Mycoplasma ovipneumoniae (M. ovipneumoniae) in their upper respiratory tract, often with little effect on health and productivity. However, for bighorn sheep (Ovis canadensis) populations, there is a link between M. ovipneumoniae infection and pneumonia, poor lamb recruitment, and high fatality rate. Because of these outcomes, preventing transmission of M. ovipneumoniae to free-ranging wild sheep has garnered interest from both the livestock and wildlife sectors. We hypothesized that treatment with intranasal and systemic enrofloxacin would reduce the prevalence of M. ovipneumoniae-positive animals in a flock of domestic sheep. Initially, the prevalence decreased in the treated group; but by 34 d post-treatment, the number of M. ovipneumoniae-positive sheep returned to near pretreatment prevalence. Key clinical message: Test-and-slaughter is a method used to reduce the risk of transmission of pneumonia-causing M. ovipneumoniae from domestic sheep and goats to free-ranging wild sheep. In an effort to find an alternative, we used enrofloxacin to treat a flock of M. ovipneumoniae-positive domestic sheep; however, long-term reduction of M. ovipneumoniae prevalence in the flock was not achieved.


Traitement antibiotique de Mycoplasma ovipneumoniae chez le mouton domestique (Ovis aries): travail à l'interface bétail-faune au Yukon, Canada. Les moutons domestiques (Ovis aries) peuvent être porteurs de la bactérie Mycoplasma ovipneumoniae (M. ovipneumoniae) dans leurs voies respiratoires supérieures, avec souvent peu d'effets sur la santé et la productivité. Cependant, pour les populations de mouflons d'Amérique (Ovis canadensis), il existe un lien entre l'infection à M. ovipneumoniae et la pneumonie, un faible recrutement d'agneaux et un taux de mortalité élevé. En raison de ces résultats, la prévention de la transmission de M. ovipneumoniae aux moutons sauvages en liberté a suscité l'intérêt des secteurs de l'élevage et de la faune sauvage. Nous avons émis l'hypothèse qu'un traitement par enrofloxacine intranasale et systémique réduirait la prévalence d'animaux positifs à M. ovipneumoniae dans un troupeau de moutons domestiques. Initialement, la prévalence a diminué dans le groupe traité; mais 34 jours après le traitement, le nombre de moutons positifs à M. ovipneumoniae est revenu à une prévalence proche de celle précédant le traitement.Message clinique clé :L'essai et l'abattage sont une méthode utilisée pour réduire le risque de transmission de M. ovipneumoniae, responsable de la pneumonie, des moutons et chèvres domestiques aux moutons sauvages en liberté. Dans le but de trouver une alternative, nous avons utilisé l'enrofloxacine pour traiter un troupeau de moutons domestiques positifs à M. ovipneumoniae; cependant, aucune réduction à long terme de la prévalence de M. ovipneumoniae dans le troupeau n'a été obtenue.(Traduit par Dr Serge Messier).


Assuntos
Doenças das Cabras , Mycoplasma ovipneumoniae , Pneumonia por Mycoplasma , Pneumonia , Doenças dos Ovinos , Carneiro da Montanha , Animais , Ovinos , Animais Selvagens , Carneiro Doméstico , Gado , Yukon , Enrofloxacina/uso terapêutico , Pneumonia/veterinária , Cabras/microbiologia , Canadá/epidemiologia , Carneiro da Montanha/microbiologia , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/prevenção & controle , Antibacterianos/uso terapêutico , Pneumonia por Mycoplasma/tratamento farmacológico , Pneumonia por Mycoplasma/epidemiologia , Pneumonia por Mycoplasma/veterinária
4.
PLoS One ; 18(10): e0293062, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37856492

RESUMO

Respiratory disease is responsible for dramatic population declines in bighorn sheep (Ovis canadensis), and respiratory pathogen diagnostics contribute to the management of bighorn populations. To create a comprehensive and consistent approach to bighorn sheep respiratory diagnostics, we created a culture-independent assay to detect and strain type Mannheimia haemolytica, Bibersteinia trehalosi, Pasteurella multocida, and Mycoplasma ovipneumoniae. The assay also detects and characterizes the Pasteurellaceae leukotoxin A gene, and broadly assesses the bacterial composition of each sample based on 16S rRNA sequences. The assay is based on a three-step approach: 1) Multiplex PCR to amplify targets including eight loci for each bacterial species, the Pasteurellaceae lktA gene, and the 16S rRNA gene 2) Library preparation, barcoding, and short-read Illumina sequencing to determine the genetic sequences of each target, and 3) Bioinformatics in the form of automated software to analyze genetic sequences. The assay was designed to assess shared pathogens between domestic and bighorn sheep, but could be useful for many applications in bighorn sheep respiratory disease research and management.


Assuntos
Mannheimia haemolytica , Doenças Respiratórias , Doenças dos Ovinos , Carneiro da Montanha , Animais , Ovinos , Carneiro da Montanha/genética , Carneiro da Montanha/microbiologia , Carneiro Doméstico , Reação em Cadeia da Polimerase Multiplex , RNA Ribossômico 16S/genética , Doenças dos Ovinos/epidemiologia , Mannheimia haemolytica/genética , Biologia Computacional
5.
PeerJ ; 11: e15625, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37576510

RESUMO

Sociality directly influences mating success, survival rates, and disease, but ultimately likely evolved for its fitness benefits in a challenging environment. The tradeoffs between the costs and benefits of sociality can operate at multiple scales, resulting in different interpretations of animal behavior. We investigated the influence of intrinsic (e.g., relatedness, age) and extrinsic factors (e.g., land cover type, season) on direct contact (simultaneous GPS locations ≤ 25 m) rates of bighorn sheep (Ovis canadensis) at multiple scales near the Waterton-Glacier International Peace Park. During 2002-2012, male and female bighorn were equipped with GPS collars. Indirect contact (GPS locations ≤ 25 m regardless of time) networks identified two major breaks whereas direct contact networks identified an additional barrier in the population, all of which corresponded with prior disease exposure metrics. More direct contacts occurred between same-sex dyads than female-male dyads and between bighorn groups with overlapping summer home ranges. Direct contacts occurred most often during the winter-spring season when bighorn traveled at low speeds and when an adequate number of bighorn were collared in the area. Direct contact probabilities for all dyad types were inversely related to habitat quality, and differences in contact probability were driven by variables related to survival such as terrain ruggedness, distance to escape terrain, and canopy cover. We provide evidence that probabilities of association are higher when there is greater predation risk and that contact analysis provides valuable information for understanding fitness tradeoffs of sociality and disease transmission potential.


Assuntos
Doenças dos Ovinos , Carneiro da Montanha , Animais , Ovinos , Feminino , Masculino , Doenças dos Ovinos/epidemiologia , Comportamento Social , Ecossistema , Comportamento Animal
6.
J Wildl Dis ; 59(4): 753-758, 2023 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-37578752

RESUMO

Respiratory disease is a significant barrier for bighorn sheep (Ovis canadensis) conservation, and a need remains for management options in both captive and free-ranging populations. We treated Mycoplasma ovipneumoniae infection in six bighorn lambs and five bighorn yearlings at two captive research facilities with twice daily oral doxycycline for 8 wk or longer. Doses of 5 mg/kg twice daily mixed in formula for lambs and 10 mg/kg twice daily mixed in moistened pellets for older lambs and yearlings were tolerated well with minimal side effects. All animals in this case report remain Mycoplasma ovipneumoniae free over 2 yr later. Further evaluation is warranted to confirm efficacy of this therapeutic approach.


Assuntos
Mycoplasma ovipneumoniae , Pneumonia por Mycoplasma , Doenças dos Ovinos , Carneiro da Montanha , Animais , Ovinos , Doxiciclina/uso terapêutico , Doenças dos Ovinos/tratamento farmacológico , Pneumonia por Mycoplasma/tratamento farmacológico , Pneumonia por Mycoplasma/veterinária
8.
Acta Biomater ; 166: 419-429, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37164299

RESUMO

Velar bone is the material that fills the horncore of bighorn sheep rams. The architectural dimensions of velar bone are orders of magnitude larger than trabecular bone, and velae are more sail-like compared to strut-like trabeculae. Velar bone is important for energy absorption and reduction of brain cavity accelerations during high energy head impacts, but velar bone material properties were previously unknown. It was hypothesized that velar bone tissue would have properties that are beneficial for increased energy absorption at the material level. Solid velar bone beams were tested using dynamic mechanical analysis and three-point bending to quantify mechanical properties. Additionally, the porosity, osteon population density, and mineral content of the solid velar sails were quantified. The velar bone damping factor (∼0.03 - 0.06) and modulus of toughness (3.9 ± 0.4 MJ/m3) were lower than other mammalian cortical bone tissues. The solid bony sails have a bending modulus (8.6 ± 0.5 GPa) that lies within the range of bending moduli values previously reported for individual trabecular struts and cortical bone tissue. The solid velar bone sails had porosity (6.7 ± 0.9 %) and bone mineral content (66 ± 1 %) in the range of cortical bone values. Interestingly, velar sails contained osteons, which are rarely found in trabecular struts. The velar bone osteon population density (5.8 ± 0.9 osteons/mm2) is in the low end of the range of values reported for cortical bone in other mammals. STATEMENT OF SIGNIFICANCE: Bighorn sheep rams sustain high energy head impacts during intraspecific combat without overt signs of brain injury. Previous studies have shown that the bony horncore plays a critical role in energy absorption and reduction of brain cavity accelerations post impact, which has implications for concussion prevention in humans. However, the material properties of the horncore velar bone were previously unknown. This study quantified the material properties and structure-property relationships of the horncore velar bone at the tissue level. Results from this study will improve our understanding of how bighorn sheep mitigate brain injury during head-to-head impacts and may inspire the design of novel materials for energy absorption applications (i.e., helmets materials that reduce concussion occurrence in humans).


Assuntos
Lesões Encefálicas , Carneiro da Montanha , Humanos , Animais , Masculino , Ovinos , Crânio , Densidade Óssea , Porosidade
9.
J Wildl Dis ; 59(1): 37-48, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36648765

RESUMO

Low lamb recruitment can be an obstacle to bighorn sheep (Ovis canadensis) conservation and restoration. Causes of abortion and neonate loss in bighorn sheep, which may affect recruitment, are poorly understood. Toxoplasma gondii is a major cause of abortion and stillbirth in domestic small ruminants worldwide, but no reports exist documenting abortion or neonatal death in bighorn sheep attributable to toxoplasmosis. Between March 2019 and May 2021, eight fetal and neonatal bighorn lamb cadavers from four western US states (Idaho, Montana, Nebraska, and Washington) were submitted to the Washington Animal Disease Diagnostic Laboratory for postmortem examination, histologic examination, and ancillary testing to determine the cause of abortion or neonatal death. Necrotizing encephalitis characteristic of toxoplasmosis was identified histologically in six of eight cases, and T. gondii infection was confirmed by PCR in five cases with characteristic lesions. Other lesions attributable to toxoplasmosis were pneumonia (3/5 cases) and myocarditis (2/5 cases). Protozoal cysts were identified histologically within brain, lung, heart, skeletal muscle, adipose tissue, or a combination of samples in all five sheep with PCR-confirmed T. gondii infections. Seroprevalence of T. gondii ranged from 40-81% of adult females sampled in the Washington population in October and November 2018-2021, confirming high rates of exposure before detection of Toxoplasma abortions in this study. Of 1,149 bighorn sheep postmortem samples submitted to Washington Animal Disease Diagnostic Laboratory between January 2000 and May 2021, 21 of which were from fetuses or neonates, a single case of chronic toxoplasmosis was diagnosed in one adult ewe. Recent identification of Toxoplasma abortions in bighorn sheep suggests that toxoplasmosis is an underappreciated cause of reproductive loss. Abortions and neonatal mortalities should be investigated through postmortem and histologic examination, particularly in herds that are chronically small, demographically stagnant, or exhibit reproductive rates lower than expected.


Assuntos
Doenças dos Ovinos , Carneiro da Montanha , Toxoplasma , Toxoplasmose Animal , Animais , Feminino , Gravidez , Estudos Soroepidemiológicos , Ovinos , Doenças dos Ovinos/diagnóstico , Doenças dos Ovinos/mortalidade , Doenças dos Ovinos/parasitologia , Toxoplasma/isolamento & purificação , Toxoplasmose Animal/diagnóstico , Toxoplasmose Animal/epidemiologia , Aborto Animal/epidemiologia , Aborto Animal/microbiologia , Conservação dos Recursos Naturais , Animais Recém-Nascidos/parasitologia
10.
Bioinspir Biomim ; 18(2)2023 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-36652719

RESUMO

Male bighorn sheep (Ovis canadensis) participate in seasonal ramming bouts that can last for hours, yet they do not appear to suffer significant brain injury. Previous work has shown that the keratin-rich horn and boney horncore may play an important role in mitigating brain injury by reducing brain cavity accelerations through energy dissipating elastic mechanisms. However, the extent to which specific horn shapes (such as the tapered spiral of bighorn sheep) may reduce accelerations post-impact remains unclear. Thus, the goals of this work were to (a) quantify bighorn sheep horn shape, particularly the cross-sectional areal properties related to bending that largely dictate post-impact deformations, and (b) investigate the effects of different tapered horn shapes on reducing post-impact accelerations in an impact model with finite element analysis. Cross-sectional areal properties indicate bighorn sheep horns have a medial-lateral bending preference at the horn tip (p= 0.006), which is likely to dissipate energy through medial-lateral horn tip oscillations after impact. Finite element modeling showed bighorn sheep native horn geometry reduced the head injury criterion (HIC15) by 48% compared to horns with cross-sections rotated by 90° to have a cranial-caudal bending preference, and by 125% compared to a circular tapered spiral model. These results suggest that the tapered spiral horn shape of bighorn sheep is advantageous for dissipating energy through elastic mechanisms following an impact. These findings can be used to broadly inform the design of improved safety equipment and impact systems.


Assuntos
Lesões Encefálicas , Traumatismos Craniocerebrais , Cornos , Carneiro da Montanha , Masculino , Animais , Estudos Transversais
11.
J Anim Ecol ; 92(7): 1456-1469, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36637333

RESUMO

Habitat fragmentation is an important driver of biodiversity loss and can be remediated through management actions aimed at maintenance of natural connectivity in metapopulations. Connectivity may protect populations from infectious diseases by preserving immunogenetic diversity and disease resistance. However, connectivity could exacerbate the risk of infectious disease spread across vulnerable populations. We tracked the spread of a novel strain of Mycoplasma ovipneumoniae in a metapopulation of desert bighorn sheep Ovis canadensis nelsoni in the Mojave Desert to investigate how variation in connectivity among populations influenced disease outcomes. M. ovipneumoniae was detected throughout the metapopulation, indicating that the relative isolation of many of these populations did not protect them from pathogen invasion. However, we show that connectivity among bighorn sheep populations was correlated with higher immunogenetic diversity, a protective immune response and lower disease prevalence. Variation in protective immunity predicted infection risk in individual bighorn sheep and was associated with heterozygosity at genetic loci linked to adaptive and innate immune signalling. Together, these findings may indicate that population connectivity maintains immunogenetic diversity in bighorn sheep populations in this system and has direct effects on immune responses in individual bighorn sheep and their susceptibility to infection by a deadly pathogen. Our study suggests that the genetic benefits of population connectivity could outweigh the risk of infectious disease spread and supports conservation management that maintains natural connectivity in metapopulations.


Assuntos
Doenças Transmissíveis , Pneumonia , Doenças dos Ovinos , Carneiro da Montanha , Animais , Ovinos , Pneumonia/veterinária , Variação Genética , Imunidade , Doenças dos Ovinos/epidemiologia
12.
J Zoo Wildl Med ; 53(3): 537-544, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36214238

RESUMO

Chemical immobilization of wildlife, required for many biological studies and management events, often induces hypoxemia and respiratory depression. Laryngeal mask airways (LMAs) have shown promise as an efficient method of airway protection during anesthesia. Nineteen wild bighorn sheep (Ovis canadensis) lambs were immobilized using an IM combination of medetomidine (0.16 ± 0.062 mg/kg), azaperone (0.20 ± 0.058 mg/kg), and alfaxalone (0.54 ± 0.21 mg/kg) via remote injection. Upon recumbency, arterial blood gas parameters, minute ventilation (VE), tidal volume (VT), and respiratory rate were measured before and after LMA placement. The VE and VT were measured via respirometer. Time to LMA placement, cuff pressure, cuff volume, and ease of placement were measured. Medetomidine was reversed with IM atipamezole at five times the medetomidine dose upon completion of procedures. Pre- and post-LMA measurements were compared using a t test or a Wilcoxon signed-rank test based on normality of the data. The LMA provided a patent airway in all lambs with a significant (P < 0.0001) increase in VE (mean [95% CI]; pre-LMA: VE = 17.3 [16.2-18.5] L/min, post-LMA: VE = 19.8 [18.6-21.0] L/min) but did not have a significant impact on partial pressure of oxygen (PaO2; pre-LMA: corrected PaO2 = 45.2 [41.2-49.2] mm Hg, post-LMA: corrected PaO2 = 47.5 [43.3-51.7] mm Hg; P = 0.19) or partial pressure of carbon dioxide (PaCO2; pre-LMA: PaCO2 = 50.4 [46.6-53.2] mm Hg, post-LMA: PaCO2 = 51.6 [48.8-55.7] mm Hg; P = 0.035) following placement. This study demonstrated that the LMA is a viable option for airway protection in wild bighorn sheep.


Assuntos
Máscaras Laríngeas , Carneiro da Montanha , Animais , Azaperona/farmacologia , Dióxido de Carbono , Máscaras Laríngeas/veterinária , Medetomidina/farmacologia , Oxigênio , Ovinos
13.
Sci Rep ; 12(1): 13807, 2022 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-35970998

RESUMO

Stable or growing populations may go extinct when their sizes cannot withstand large swings in temporal variation and stochastic forces. Hence, the minimum abundance threshold defining when populations can persist without human intervention forms a key conservation parameter. We identify this threshold for many populations of Caprinae, typically threatened species lacking demographic data. Doing so helps triage conservation and management actions for threatened or harvested populations. Methodologically, we used population projection matrices and simulations, with starting abundance, recruitment, and adult female survival predicting future abundance, growth rate (λ), and population trend. We incorporated mean demographic rates representative of Caprinae populations and corresponding variances from desert bighorn sheep (Ovis canadensis nelsoni), as a proxy for Caprinae sharing similar life histories. We found a population's minimum abundance resulting in ≤ 0.01 chance of quasi-extinction (QE; population ≤ 5 adult females) in 10 years and ≤ 0.10 QE in 30 years as 50 adult females, or 70 were translocation (removals) pursued. Discovering the threshold required 3 demographic parameters. We show, however, that monitoring populations' relationships to this threshold requires only abundance and recruitment data. This applied approach avoids the logistical and cost hurdles in measuring female survival, making assays of population persistence more practical.


Assuntos
Espécies em Perigo de Extinção , Ruminantes/crescimento & desenvolvimento , Animais , Feminino , Humanos , Dinâmica Populacional , Ruminantes/fisiologia , Carneiro da Montanha/crescimento & desenvolvimento , Carneiro da Montanha/fisiologia
14.
Oecologia ; 199(4): 809-817, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35964263

RESUMO

Anthropogenic climate change and habitat alterations increase the importance of understanding the causes and consequences of variation in phenological traits. Although the timing of phenological events may vary in response to both direct and mediated effects, methods to measure and distinguish direct and mediated effects have seldom been used. We used a Bayesian structural equation model (SEM) to evaluate potential direct and mediated effects of intrinsic individual and environmental factors on the timing and progression of spring molt in bighorn sheep. The SEM showed that molt phenology varied across years, was earlier in prime-aged and in heavier individuals, slower in males, and later in lactating ewes, especially if they were light. These results highlight how individual variation in intrinsic traits and life-history leads to substantial variation in a phenological trait. Indirect effects in the SEM predicted a delay in sheep molt phenology at high population density mediated through negative density effects on body mass and lactation probability. Cooler temperatures in late spring were also predicted to delay molt phenology via a negative effect on body mass. Finally, lactation reduced ewe mass which was predicted to delay molt phenology. This mediated effect thus increased the total delay (sum of direct and mediated effects) in molt phenology experience by lactating ewes. Our results underline the importance of estimating direct and indirect effects when modeling phenological traits. Because indirect effects could substantially affect estimates of total plasticity, they should be critically important to accurately predict phenological mismatches and demographic consequences of environmental change.


Assuntos
Adaptação Fisiológica , Mudança Climática , Muda , Carneiro da Montanha , Animais , Teorema de Bayes , Feminino , Lactação , Masculino , Estações do Ano , Ovinos
15.
J Wildl Dis ; 58(3): 689-691, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35512297

RESUMO

An adult female Rocky Mountain bighorn sheep (Ovis canadensis canadensis) was euthanized because of a large mandibular mass. Histopathology revealed an ameloblastic fibro-odontoma, a rare odontogenic neoplasia.


Assuntos
Odontoma , Doenças dos Ovinos , Carneiro da Montanha , Alberta , Animais , Feminino , Odontoma/complicações , Odontoma/veterinária , Ovinos
16.
J Wildl Dis ; 58(3): 592-598, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35584403

RESUMO

From February to May 2021, four nonmigratory rams from the Radium-Stoddart bighorn sheep (BHS; Ovis canadensis) herd in the Rocky Mountains of southeastern British Columbia, Canada, died from infection with the giant liver fluke, Fascioloides magna. Affected animals were emaciated, weak, and lethargic or were found dead. Gross lesions, histopathology, and parasite burdens were consistent with those reported in experimentally infected BHS, domestic sheep, and other aberrant hosts. Although BHS range does not typically overlap with fluke-contaminated aquatic habitats, the change in migratory behavior recently observed in some Radium-Stoddart rams may have exposed the affected animals to F. magna. We describe clinical signs and gross and histopathologic findings of hepatobiliary trematodiasis associated with F. magna in free-ranging BHS. From experimental data and our findings, giant liver fluke is pathogenic and is a threat to the conservation of the Radium-Stoddart BHS herd and other BHS herds in endemic F. magna regions.


Assuntos
Fasciolidae , Rádio (Elemento) , Doenças dos Ovinos , Carneiro da Montanha , Animais , Colúmbia Britânica/epidemiologia , Masculino , Ovinos , Doenças dos Ovinos/epidemiologia
17.
J Helminthol ; 96: e26, 2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35403577

RESUMO

This study aimed to describe the shedding pattern of gastrointestinal parasite eggs by a wild population of desert bighorn sheep (DBS; Ovis canadensis) in northern Mexico. Seventy-five fresh faecal samples were collected from the ground in each season within an hour after being expelled by these animals. The generalized linear mixed model showed that eggs per gram of faeces were highest in winter (577 ± 399) and lowest in summer (260 ± 198). Generalized linear models revealed that Strongyloides spp. predominated during most seasons with a peak in summer (85% of faecal samples analysed) and the absence of this helminth in winter. Nematodirus spp. was another helminth present in three seasons, with the presence of this nematode in 35% of the faecal samples in spring and 0% in summer. Other parasites in DBS faeces included Bunostomun spp., Trichostrongylus spp., Cooperia spp., Mecistocirrus digitatus, Haemonchus contortus, Chabertia ovina and Eimeria ovinoidalis. There were differences among seasons in the percentage of these helminths and coccidia in faecal samples for all these parasites. It was concluded that helminths egg output in DBS in a semi-arid rangeland is lowest in summer and spring and highest in autumn and winter. Furthermore, it was shown that DBS in the study site do not suffer from severe parasite burden. Therefore, this nematode parasite burden is compatible with the conservation and well-being of this particular population.


Assuntos
Helmintos , Enteropatias Parasitárias , Nematoides , Infecções por Nematoides , Parasitos , Doenças dos Ovinos , Carneiro da Montanha , Animais , Fezes/parasitologia , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/veterinária , México/epidemiologia , Infecções por Nematoides/parasitologia , Contagem de Ovos de Parasitas , Prevalência , Estações do Ano , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/parasitologia
18.
Proc Biol Sci ; 289(1971): 20212534, 2022 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-35317671

RESUMO

In polygynous species, secondary sexual traits such as weapons or elaborate ornaments have evolved through intrasexual competition for mates. In some species, these traits are present in both sexes but are underdeveloped in the sex facing lower intrasexual competition for mates. It is often assumed that these underdeveloped sexually selected traits are a vestige of strong sexual selection on the other sex. Here, we challenge this assumption and investigate whether the expression of secondary sexual traits is associated with fitness in female bighorn sheep. Analyses of 45 years of data revealed that female horn length at 2 years, while accounting for mass and environmental variables, is associated with younger age at primiparity, younger age of first offspring weaned, greater reproductive lifespan and higher lifetime reproductive success. There was no association between horn length and fecundity. These findings highlight a potential conservation issue. In this population, trophy hunting selects against males with fast-growing horns. Intersexual genetic correlations imply that intense selective hunting of large-horned males before they can reproduce can decrease female horn size. Therefore, intense trophy hunting of males based on horn size could reduce female reproductive performance through the associations identified here, and ultimately reduce population growth and viability.


Assuntos
Cornos , Carneiro da Montanha , Animais , Feminino , Caça , Longevidade , Masculino , Fenótipo , Ovinos
19.
Vet Microbiol ; 265: 109334, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35033769

RESUMO

Mycoplasma ovipneumoniae (M. ovipneumoniae) is a respiratory pathogen associated with mild to moderate respiratory disease in domestic lambs and severe pneumonia outbreaks in wild ruminants such as bighorn sheep. However, whether M. ovipneumoniae by itself causes clinical respiratory disease in domestic sheep in the absence of secondary bacterial pathogens is still unclear. The goal of our study was to better understand the role of M. ovipneumoniae as a respiratory pathogen in domestic sheep and to explore potential antibiotic treatment approaches. Therefore, we inoculated four 4-month-old, specific-pathogen-free lambs with fresh nasal wash fluids from M. ovipneumoniae-infected sheep. The lambs were monitored for M. ovipneumoniae colonization, M. ovipneumoniae-specific antibodies, clinical signs, and cellular and molecular correlates of lung inflammation for eight weeks. All lambs then were treated with gamithromycin and observed for an additional four weeks. M. ovipneumoniae inoculation resulted in stable colonization of the upper respiratory tract in all M. ovipneumoniae-inoculated, but in none of the four mock-infected control lambs. All M. ovipneumoniae-infected lambs developed a robust antibody response to M. ovipneumoniae within 2 weeks. However, we did not observe significant signs of respiratory disease, evidence of lung damage or inflammation in any of the infected lambs. Interestingly, treatment with gamithromycin, which blocked growth of the M. ovipneumoniae in vitro, failed to reduce M. ovipneumoniae colonization. These observations indicate that, in the absence of co-infections, M. ovipneumoniae caused asymptomatic colonization of the upper respiratory tract that was resistant to clearance by the host immune response and by gamithromycin treatment.


Assuntos
Mycoplasma ovipneumoniae , Doenças dos Ovinos , Carneiro da Montanha , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções Assintomáticas , Ovinos , Doenças dos Ovinos/epidemiologia
20.
Glob Chang Biol ; 28(1): 21-32, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34619002

RESUMO

In species with long gestation, females commit to reproduction several months before parturition. If cues driving conception date are uncoupled from spring conditions, parturition could be mistimed. Mismatch may increase with global change if the rate of temporal changes in autumn cues differs from the rate of change in spring conditions. Using 17 years of data on climate and vegetation phenology, we show that autumn temperature and precipitation, but not vegetation phenology, explain parturition date in bighorn sheep. Although autumn cues drive the timing of conception, they do not predict conditions at parturition in spring. We calculated the mismatch between individual parturition date and spring green-up, assessed whether mismatch increased over time and investigated the consequences of mismatch on lamb neonatal survival, weaning mass and overwinter survival. Mismatch fluctuated over time but showed no temporal trend. Temporal changes in green-up date did not lead to major fitness consequence of mismatch. Detailed data on individually marked animals revealed no effect of mismatch on neonatal or overwinter survival, but lamb weaning mass was negatively affected by mismatch. Capital breeders might be less sensitive to mismatch than income breeders because they are less dependent on daily food acquisition. Herbivores in seasonal environments may access sufficient forage to sustain lactation before or after the spring 'peak' green-up, and partly mitigate the consequences of a mismatch. Thus, the effect of phenological mismatch on fitness may be affected by species life history, highlighting the complexity in quantifying trophic mismatches in the context of climate change.


Assuntos
Mudança Climática , Carneiro da Montanha , Animais , Feminino , Herbivoria , Estações do Ano , Ovinos , Temperatura
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