28 research outputs found

    On the interplay between hypothermia and reproduction in a high arctic ungulate

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    For free-ranging animals living in seasonal environments, hypometabolism (lowered metabolic rate) and hypothermia (lowered body temperature) can be effective physiological strategies to conserve energy when forage resources are low. To what extent such strategies are adopted by large mammals living under extreme conditions, as those encountered in the high Arctic, is largely unknown, especially for species where the gestation period overlaps with the period of lowest resource availability (i.e. winter). Here we investigated for the first time the level to which high arctic muskoxen (Ovibos moschatus) adopt hypothermia and tested the hypothesis that individual plasticity in the use of hypothermia depends on reproductive status. We measured core body temperature over most of the gestation period in both free-ranging muskox females in Greenland and captive female muskoxen in Alaska. We found divergent overwintering strategies according to reproductive status, where pregnant females maintained stable body temperatures during winter, while non-pregnant females exhibited a temporary decrease in their winter body temperature. These results show that muskox females use hypothermia during periods of resource scarcity, but also that the use of this strategy may be limited to non-reproducing females. Our findings suggest a trade-of between metabolically driven energy conservation during winter and sustaining foetal growth, which may also apply to other large herbivores living in highly seasonal environments elsewhere.publishedVersio

    Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): bluetongue

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    An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore

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    Beumer LT, Pohle JM, Schmidt NM, et al. An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore. Movement Ecology. 2020;8(1): 25

    On the interplay between hypothermia and reproduction in a high arctic ungulate

    Get PDF
    For free-ranging animals living in seasonal environments, hypometabolism (lowered metabolic rate) and hypothermia (lowered body temperature) can be effective physiological strategies to conserve energy when forage resources are low. To what extent such strategies are adopted by large mammals living under extreme conditions, as those encountered in the high Arctic, is largely unknown, especially for species where the gestation period overlaps with the period of lowest resource availability (i.e. winter). Here we investigated for the first time the level to which high arctic muskoxen (Ovibos moschatus) adopt hypothermia and tested the hypothesis that individual plasticity in the use of hypothermia depends on reproductive status. We measured core body temperature over most of the gestation period in both free-ranging muskox females in Greenland and captive female muskoxen in Alaska. We found divergent overwintering strategies according to reproductive status, where pregnant females maintained stable body temperatures during winter, while non-pregnant females exhibited a temporary decrease in their winter body temperature. These results show that muskox females use hypothermia during periods of resource scarcity, but also that the use of this strategy may be limited to non-reproducing females. Our findings suggest a trade-of between metabolically driven energy conservation during winter and sustaining foetal growth, which may also apply to other large herbivores living in highly seasonal environments elsewhere

    Adverse events while awaiting myocardial revascularization: a systematic review and meta-analysis.

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    OBJECTIVES: The aim of the current study was to estimate adverse event rates while awaiting myocardial revascularization and review criteria for prioritizing patients. METHODS: A PubMed search was performed on 19 January 2015, to identify English-language, original, observational studies reporting adverse events while awaiting coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI). Rates of death, non-fatal myocardial infarction (MI) and emergency revascularization were calculated as occurrence rates per 1000 patient-weeks and pooled using random-effects models. RESULTS: The search yielded 1323 articles, of which 22 were included with 66 410 patients and 607 675 patient-weeks on the wait list. When awaiting CABG, rates per 1000 patient-weeks were 1.1 [95% confidence interval 0.9-1.3] for death, 1.0 [0.6-1.6] for non-fatal MI and 1.8 [0.8-4.1] for emergency revascularization. Subgroup analyses demonstrated consistent outcomes, and sensitivity analyses demonstrated comparable event rates with low heterogeneity. Higher urgency of revascularization was based primarily on angiographic complexity, angina severity, left ventricular dysfunction and symptoms on stress testing, and such patients with a semi-urgent status had a higher risk of death than patients awaiting elective revascularization (risk ratio at least 2.8). Individual studies identified angina severity and left ventricular dysfunction as most important predictors of death when awaiting CABG. Adverse rates per 1000 patient-weeks for patients awaiting PCI were 0.1 [95% confidence interval 0.0-0.4] for death, 0.4 [0.1-1.2] for non-fatal MI and 0.7 [0.4-1.4] for emergency revascularization but were based on only a few old studies. CONCLUSIONS: Rates of death, non-fatal MI and emergency revascularization when awaiting myocardial revascularization are infrequent but higher in specific patients. Countries that not yet have treatment recommendations related to waiting times should consider introducing a maximum to limit adverse events, particularly when awaiting CABG
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