Track topics on Twitter Track topics that are important to you
Red deer, Cervus elaphus, like other temperate-zone animals, show a large seasonal fluctuation in energy intake and expenditure. Many seasonal phenotypic adjustments are coordinated by endogenous signals entrained to the photoperiod. The cues determining variation in the resting metabolism of ungulates remain equivocal, however, largely because of the confounding effects of food intake and thus the heat increment of feeding. To distinguish endogenous seasonal and environmental effects on metabolism, we subjected 15 female red deer to two feeding treatments, 80% food restriction and low/high protein content, over two winter seasons in a cross-over design experiment. We used rumen-located transmitters to measure heart rate and rumen temperature, which provided indices of metabolism and core body temperature, respectively. Our mixed model (R(2)=0.85) indicated a residual seasonal effect on mean daily heart rate that was unexplained by the pellet food treatments, activity, body mass or air temperature. In addition to an apparently endogenous down-regulation of heart rate in winter, the deer further reduced heart rate over about 8 days in response to food restriction. We found a strong correlation between rumen temperature and seasonal or periodic variation in heart rate. An effect of lowered rumen (and hence core body) temperature was enhanced during winter, perhaps owing to peripheral cooling, which is known to accompany bouts of hypometabolism. Our experimental results therefore support the hypothesis that a reduction in body temperature is a physiological mechanism employed even by large mammals, like red deer, to reduce their energy expenditure during periods of negative energy balance.
Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstrasse 1, 1160, Vienna, Austria.
This article was published in the following journal.
Name: The Journal of experimental biology
In the past, Listeria monocytogenes has been isolated from game feces and meat. However, less information is available on the occurrence of L. monocytogenes in other specimens originating from game an...
Resting heart rate has long been thought to be a risk factor in cardiovascular disease and a prognostic factor in heart failure. β-Blockers were originally used in heart failure for their heart rate ...
Background: Diurnal temperature range (DTR) is an important index of climate change and variability. It is also a risk factor affecting human health. However, limited evidence is available to illustra...
Ectothermic animals are susceptible to temperature changes such as cold shock with seasons. To survive through a cold shock or season, ectotherms have developed unique strategies. Our interest is focu...
It has long been known that life span is inversely related to resting heart rate in most organisms. This association between heart rate and survival has been attributed to the metabolic rate, which is...
The purpose of this study is to find a way of detecting infection earlier in patients receiving bone marrow transplant. This is accomplished by continuous individualized monitoring of hear...
The purpose of this study is to determine: 1. the effect of ambient temperature on the rate of core temperature change from 1 to 3 hours after induction of anesthesia (linear phase...
The purpose of this study is to investigate the effects of heart rates (including maximum heart rate, average heart rate and minimum heart rate) and variability of heart rate on image qual...
This will be a double blind randomized crossover study of patients with congestive heart failure and a heart rate dependent upon a permanent pacemaker. Thus, at all times the heart rate ca...
The purpose of this study is to determine the mechanisms of chronotropic incompetence (inability to increase heart rate with exercise) in patients with heart failure and preserved ejection...
The heart rate of the FETUS. The normal range at term is between 120 and 160 beats per minute.
The processes of heating and cooling that an organism uses to control its temperature.
Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.
Apparatus that provides mechanical circulatory support during open-heart surgery, by passing the heart to facilitate surgery on the organ. The basic function of the machine is to oxygenate the body's venous supply of blood and then pump it back into the arterial system. The machine also provides intracardiac suction, filtration, and temperature control. Some of the more important components of these machines include pumps, oxygenators, temperature regulators, and filters. (UMDNS, 1999)
A pumping mechanism that duplicates the output, rate, and blood pressure of the natural heart. It may replace the function of the entire heart or a portion of it, and may be an intracorporeal, extracorporeal, or paracorporeal heart. (Dorland, 28th ed)
Cardiovascular disease (CVD)
Acute Coronary Syndromes (ACS) Blood Cardiovascular Dialysis Hypertension Stent Stroke Vascular Cardiovascular disease (CVD) includes all the diseases of the heart and circulation including coronary heart disease (angina...
Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ingested by an organism ...