Topic:Temperature
Temperature regulation in horses involves physiological processes that maintain the animal's core body temperature within a narrow, optimal range despite external environmental changes. Horses, being homeothermic animals, rely on mechanisms such as sweating, respiration, and blood flow adjustments to dissipate excess heat or conserve warmth. These thermoregulatory processes are influenced by factors such as exercise, humidity, and ambient temperature. Variations in temperature can affect a horse's performance, health, and overall well-being. This page aggregates peer-reviewed research studies and scholarly articles that explore the mechanisms, effects, and implications of temperature regulation in equine physiology.
Analysis of Ca2+/Mg2+ selectivity in alpha-lactalbumin and Ca(2+)-binding lysozyme reveals a distinct Mg(2+)-specific site in lysozyme. The triggering of Ca(2+) signaling pathways relies on Ca(2+)/Mg(2+) specificity of proteins mediating these pathways. Two homologous milk Ca(2+)-binding proteins, bovine alpha-lactalbumin (bLA) and equine lysozyme (EQL), were analyzed using the simplest "four-state" scheme of metal- and temperature-induced structural changes in a protein. The association of Ca(2+)/Mg(2+) by native proteins is entropy-driven. Both proteins exhibit strong temperature dependences of apparent affinities to Ca(2+) and Mg(2+), due to low thermal stabilities of their apo-forms and relatively high unfavorable enthalpi...
[The extent of temperature sense and pain appreciation recovery in the dermatomes of cauda equine roots after lumbar intervertebral dischernia elimination]. Temperature sense and pain appreciation has been studied in the dermatomes of cauda equine roots in patients with lumbar intervertebral disc hernia before treatment, in the immediate and long-term periods of observation after disc hernia elimination. Temperature sense and pain appreciation has been determined to be disordered not only in the dermatome of compressed root, but in the dermatomes located proximally and distally as well. The manifestation of negative changes was observed to a greater extent during temperature sense examination. After disc hernia elimination the recovery of temperat...
Effect of temperature on race times on a synthetic surface. Differences in racing times have been noted on synthetic track surfaces that appear to depend on the temperature of the track. No published study to date has considered this effect in a systematic manner. Objective: To investigate the relationship between temperature of track and speed of horses racing on a synthetic surface. Potential changes in the wax component of the synthetic track were investigated as one possible cause of changes in the track speed at the temperatures observed. Methods: At Del Mar racetrack (California, USA), the air, surface and subsurface temperatures at 4 depths in t...
Membrane permeability parameters for freezing of stallion sperm as determined by Fourier transform infrared spectroscopy. Cellular membranes are one of the primary sites of injury during freezing and thawing for cryopreservation of cells. Fourier transform infrared spectroscopy (FTIR) was used to monitor membrane phase behavior and ice formation during freezing of stallion sperm. At high subzero ice nucleation temperatures which result in cellular dehydration, membranes undergo a profound transition to a highly ordered gel phase. By contrast, low subzero nucleation temperatures, that are likely to result in intracellular ice formation, leave membrane lipids in a relatively hydrated fluid state. The extent of free...
Heat shock protein 70 gene expression in equine blastocysts after exposure of oocytes to high temperatures in vitro or in vivo after exercise of donor mares. Heat above homeothermy can be detrimental to embryonic development, and cells may produce heat shock proteins to try to mitigate these effects. The authors examined the developmental competence of equine oocytes after a single heat exposure (42 degrees C, 2 or 4 h) during early or late stages of in vitro maturation. Rates of nuclear maturation, cleavage after intracytoplasmic sperm injection, and advanced embryonic development (morula or blastocyst) were compared to those for unexposed controls. Concentrations of heat shock protein 70 (HSPA1A) mRNA were determined by real-time RT-PCR in result...
Stabling causes a significant increase in the pH of the equine airway. Regulation of pH homeostasis in the equine lung is poorly understood. Measurement of exhaled breath condensate (EBC) pH provided a simple, highly repeatable and noninvasive method for the longitudinal investigation of changes in airway pH in response to environmental changes. Stabling of horses was found to lead to a small (approximately 100-200 parts/billion) but significant (P < 0.001) increase in ambient ammonia concentration when compared to pasture. This increase in exposure to ambient ammonia concentration was associated with significant (P = 0.002) increases in EBC pH and exhaled amm...
Rho kinase activation and ROS production contributes to the cooling enhanced contraction in cutaneous equine digital veins. A decrease in environmental temperature can directly affect the contractility of cutaneous vasculature, mediated in part by alpha(2)-adrenoceptors. Most of the cellular mechanisms underlying the cooling-enhanced contractility to alpha(2)-adrenoceptor agonists have been reported in cutaneous arteries but little information is available on cutaneous veins. To investigate the cellular mechanisms associated with the cooling-enhanced contraction to UK-14304 (alpha(2)-adrenoceptor agonist), isolated equine digital veins (EDVs) were studied at 30 degrees C and 22 degrees C. The effects of inhibitors ...
Mass gathering medical care: to calculate the Medical Usage Rate of Galway Races. Medical Usage Rate (MUR) of Galway Races: The Galway Races is the most popular horse-racing festival in Ireland. It takes place for a week starting from the last Monday in July. The races are held at Ballybrit race course in Galway. During the 7 days of racing, about 180,000 people attend. The average temperature in Galway around that time of the year is around 15-200C. The aim of this study is to calculate the MUR of Galway Races and to develop a model to predict the MUR for Galway Races in future. The MUR of Galway Races is calculated by looking retrospectively at the medical records of the ...
Magnetic resonance signal changes during time in equine limbs refrigerated at 4 degrees C. When ex vivo magnetic resonance (MR) imaging studies are undertaken, specimen conservation should be taken into account when interpreting MR imaging results. The purpose of this study was to assess MR changes during time in the anatomic structures of the equine digit on eight cadaver limbs stored at 4 degrees C. The digits were imaged within 12 h after death and then after 1, 2, 7, and 14 days of refrigeration. After the last examination, four feet were warmed at room temperature for 24 h and reimaged. Sequences used were turbo spin echo (TSE) T1, TSE T2, short tau inversion recovery (STIR), a...
Proliferation of Streptococcus zooepidemicus and Pseudomonas aeruginosa within a simulated subpalpebral lavage flushed with equine serum. To evaluate whether equine serum administered via a simulated subpalpebral lavage system (SPL) supports proliferation of Streptococcus zooepidemicus or Pseudomonas aeruginosa within the tubing. Methods: A sterile i.v. catheter with injection cap was inserted into sterilized silicone tubing (Mila). To mimic an SPL within the dorsal conjunctival fornix, the tubing was secured to an elevated platform. The tip of the tubing extended from the platform into a vial containing culture medium just inoculated with approximately 1.5 x 10(8) CFU/mL P. aeruginosa or S. zooepidemicus. To mimic administratio...
In vitro comparison of cortical bone temperature generation between traditional sequential drilling and a newly designed step drill in the equine third metacarpal bone. To compare heat generation and time to finish between a new step drill and sequential drilling in order to create a 6.2 mm pilot hole for insertion of a positive profile transfixation pin into the equine third metacarpal bone. Methods: Nine pairs of equine third metacarpal bones from cadavers of adult horses were used. Maximum temperature rise of the bone was measured continuously at the cis- and trans-cortices 1, 2 and 3 mm from the final pilot hole during creation of a 6.2 mm hole using a step drill and sequential drilling with 4.5, 5.5 and 6.2 mm drill bits. Five holes were drilled into the...
Functional role of alpha2-adrenoceptor subtypes in the cooling-enhanced vasoconstriction of isolated cutaneous digital veins of the horse. Cooling-enhanced contractile responses in cutaneous arteries have been reported to involve the activation of alpha(2C)-adrenoceptors, but their role in cutaneous veins is not clearly understood. The aim was to pharmacologically characterize the subtype of postsynaptic alpha(2)-adrenoceptors in the equine digital vein mediating contraction at two temperatures. The increase in isometric tension of endothelium-denuded equine digital vein in response to UK-14304 was studied in the absence and presence of relatively selective alpha(2)-adrenoceptor antagonists at temperatures of either 30 degrees C ...
Effects of fecal collection and storage factors on strongylid egg counts in horses. Fecal analyses are becoming increasingly important for equine establishments as a means of parasite surveillance and detection of anthelmintic resistance. Although several studies have evaluated various egg counting techniques, little is known about the quantitative effects of pre-analytic factors such as collection and storage of fecal samples. This study evaluated the effects of storage temperature, storage time and airtight versus open-air storage on fecal egg counts. The experimental protocols were replicated in two study locations: Copenhagen, Denmark and Athens, Georgia, USA. In both loc...
Viability of Rhodococcus equi and Parascaris equorum eggs exposed to high temperatures. There is great concern about the potential pathogen contamination of horse manure compost spread in the same fields horses graze in. To ensure that pathogen destruction occurs, temperatures need to be sufficiently high during composting. Here, we investigated the survival rate of two marker organisms, Rhodococcus equi and Parascaris equorum eggs, exposed to temperatures potentially encountered during horse manure composting. Our results show that the time required to achieve a 1 log10 reduction in R. equi population (D-value) are 17.1 h (+/-1.47) at 45 degrees C, 8.6 h (+/-0.28) at 50 degrees ...
Managing the effects of the weather on the Equestrian Events of the 2008 Beijing Olympic Games. This paper describes a 3 year project to investigate and manage the effects of the local weather conditions on horses competing in the 2008 Olympic Games. The first part of the investigation involved estimating the expected heat load on horses during competition and suggesting measures to ensure their safety based on data collected from dedicated weather monitoring at both Olympic venues during August 2006, 2007 and 2008. The aim of the second part was to establish a reliable system of point forecasting to monitor and predict inclement weather that might affect the competitions. This involved ...
Stability of equine IgG antivenoms obtained by caprylic acid precipitation: towards a liquid formulation stable at tropical room temperature. Liquid formulations of antivenom require a cold chain for their distribution and storage, especially in tropical countries characterized by high temperature and humidity (climatic zone IV). Since cold chain is often deficient in many regions, there is a need to develop novel formulations of liquid antivenoms of higher stability at room temperatures. The effect of addition of the polyols mannitol and sorbitol on the thermal stability of caprylic acid-fractionated equine whole IgG antivenoms was assessed in preparations having different concentrations of protein and phenol. Results evidenced tha...
Reproducibility of airway responsiveness in horses using flowmetric plethysmography and histamine bronchoprovocation. Inflammatory airway disease has a high prevalence in horses, but is often a diagnostic challenge. Flowmetric plethysmography and histamine bronchoprovocation (FP/HBP) is a simple and effective tool for diagnosis, but reproducibility of these measurements made over time has not been established. Objective: We hypothesize that the measurement of airway responsiveness in horses using FP/HBP is consistent over both short and long periods of time. Methods: Twenty-nine healthy adult horses from 2 university herds. Methods: In this prospective experimental study, airway responsiveness was determined ...
Multivariate analysis for characteristics of heat tolerance in horses in Brazil. The environment in which the horse is reared affects its ability to maintain thermal balance which is in turn related to thermal characteristics and regulatory physiological mechanisms. In this study a multivariate analysis of physiological traits in relation to heat tolerance in horses was carried out in the Federal District, Brazil. The aim was to test the ability of these analyses to separate groups of animals and determine which physiological traits are most important in the adaptation to heat stress. Forty adult horses (4 to 13 years) were used, ten from each of four different genetic gro...
Animal-related injuries: epidemiological and meteorological features. This is a retrospective and registry-based descriptive study including animal- related injuries represented by the most crowded Emergency Department (ED) in Eastern Turkey over a period of two years. Animal-related injuries were 0.2% of all ED admittances; dominant in males and were high in summer. 68% of the subjects were exposed to mammalians. Most prominent injuries were dog bites (30%), horse (22%) and livestock-related injuries (12%). Hospitalization was significantly higher in mammalian animal injuries compared to non-mammalian injuries. The highest hospitalization rate was measured for ...
Assessment of pregnancy in the late-gestation mare using digital infrared thermography. The objective of this study was to investigate use of digital infrared thermal imaging (DITI) to determine whether surface temperature gradient differences exist between pregnant and nonpregnant mares as a noncontact method to determine pregnancy status. On the day measurements were collected, each pregnant mare (n=10; beginning at 292.4+/-1.4 d of gestation) was paired with a nonpregnant mare (n=17). Ambient temperature, DITI measurements (left and right flank, wither temperatures [i.e., animal surface control] and background temperature), and rectal temperatures were obtained every 7 d for 5...
Stability of pergolide mesylate oral liquid at room temerature. Pergolide mesylate (proprietary name Permax) is used to treat equine Cushing's syndrome. Since pergolide mesylate has been removed from the market, the tablets are no longer available. Therefore, pergolide mesylate preparations have to be compounded for veterinary use. Compounded oral liquid formulations have been given arbitrary beyond-use dates of 14 days (aqueous) to 90 days (oil based). The goal of this study was to determine the stability of a 0.2 mg/mL pergolide oral liquid prepared according to a previousy published formulation and stored at room temperature. The sample preparation and ...
Assessment of subclinical venous catheter-related diseases in horses and associated risk factors. A total of 102 horses that had a catheter introduced intravenously to facilitate treatment had the catheterised jugular vein and contralateral vein examined by ultrasound every 48 hours. Subclinical complications were defined by thrombus formation or thickening of the venous wall, and the data were analysed to establish risk factors for the development of these complications. The horses with a rectal temperature above 38.5 degrees C when the catheter was introduced were four times more likely to develop complications, than the horses with a lower temperature. The administration of a NSAID whil...
Effects of compounding and storage conditions on stability of pergolide mesylate. To determine the effects of temperature and light over a 35-day period on stability of pergolide mesylate after compounding in an aqueous vehicle. Methods: Evaluation study. Methods: Pergolide was compounded into a formulation with a final target concentration of 1 mg/mL. Aliquots of the formulation were then stored at -20 degrees, 8 degrees, 25 degrees, or 37 degrees C without exposure to light or at 25 degrees C with exposure to light for 35 days. Samples were assayed in triplicate by means of high-pressure liquid chromatography immediately after compounding and after 1, 7, 14, 21, and 35 da...
Can programmed cell death be induced in post-ejaculatory bull and stallion spermatozoa? Apoptosis is common during spermatogenesis. Here, it was tested whether apoptosis could be induced in sperm after ejaculation. There were several lines of evidence to indicate that sperm are resistant to induction of apoptosis. First, incubation of bull sperm at temperatures characteristic of normothermia (38.5 degrees C) or heat shock (40 and 41 degrees C) for 4h did not increase the proportion of sperm positive for the TUNEL reaction. There was also no reduction in mitochondrial polarity caused by exposure to 40 or 41 degrees C. Incubation at 38.5 degrees C (least-squares mean+/-SEM=4.0+/-1....
Reproductive performance of donor mares subsequent to eFSH treatment in early vernal transition: Comparison between the first, second, and mid-season estrous cycles of the breeding season. The objective was to compare the reproductive performances associated with the first (Cycle-1), second (Cycle-2), and mid-season (MS-Cycle) ovulations of the breeding season in donor mares that were treated with equine-FSH (eFSH) in the early vernal transition. Mares (n=15) kept under ambient light were examined ultrasonographically per-rectum starting January 30. When an ovarian follicle > or =25mm in diameter was detected, twice daily eFSH treatments were initiated. The eFSH treatments ceased when a follicle > or =35mm was detected, and 36h later hCG was administered. Thereafter, mares were ...
Environmental risk factors for equine West Nile virus disease cases in Texas. West Nile Virus (WNV) was first detected in the Texas equine population during June 2002. Infection has since spread rapidly across the state and become endemic in the equine population. Environmental risk factors associated with equine WNV attack rates in Texas counties during the period 2002 to 2004 were investigated. Equine WNV attack rates were smoothed using an empirical Bayesian model, because of the variability among county equine populations (range 46-9,517). Risk factors investigated included hydrological features (lakes, rivers, swamps, canals and river basins), land cover (tree, mos...