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.
Gospodarek E.Direct and intermediate hemolytic activity of 526 strains of Acinetobacter was investigated. Their ability to produce lipase and lecithinase was also studied. Measurements were performed parallely on human, horse, sheep and bovine erythrocytes. Direct hemolytic activity was exhibited by 16% of tested strains (17 out of 24 strains of A. haemolyticus). Human, sheep and bovine erythrocytes were useful for testing the hemolytic activity of Acinetobacter. The hemolysis was occurring faster and was visible more frequently during incubation at 37 degrees C. Indirect hemolytic activity was observed in...
Reisen WK, Meyer RP, Presser SB, Hardy JL.The extrinsic incubation rate (inverse of the time in days from infection to median transmission) of western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses by laboratory strains of Culex tarsalis Coquillett increased as a linear function of incubation temperatures from 10 to 30 degrees C. The estimated temperatures for zero transmission thresholds (intercept of the X axis) were 10.9 and 14.9 degrees C, and the number of degree days above these thresholds required for median transmission (inverse of the slope) was 67.6 and 115.2, respectively. Although the bodies of mos...
Craig AM, Blythe LL, Rowe KE, Lassen ED, Barrington R, Walker KC.Recent evidence concerning the pathogenesis of equine degenerative myeloencephalopathy indicated that low blood alpha-tocopherol values are a factor in the disease process. Variables that could be introduced by a veterinarian procuring, transporting, or storing samples were evaluated for effects on alpha-tocopherol concentration in equine blood. These variables included temperature; light; exposure to the rubber stopper of the evacuated blood collection tube; hemolysis; duration of freezing time, with and without nitrogen blanketing; and repeated freeze/thaw cycles. It was found that hemolysis...
Marr CM.Microwave thermographs were recorded from 77 normal horses. In 51% the lowest temperature was recorded in the mid-metacarpal region, and in 41% it was in the distal metacarpal region. The mean temperature of the normal limbs ranged from 25.04 to 37.4 degrees C. Maximum temperature differences between symmetrical points in both forelimbs ranged from 0 to 5.33 degrees C and differences in mean limb temperatures between both forelimbs ranged from 0 to 2.91 degrees C. In 48 horses with acute (less than 4 weeks' duration) injury of the superficial digital flexor tendon (SDFT) (36 unilateral, 12 bil...
Manohar M, Duren SE, Sikkes B, Day J, Baker JP.Distribution of blood flow among various respiratory muscles was examined in 8 healthy ponies during submaximal exercise lasting 30 minutes, using radionuclide labeled 15-microns diameter microspheres injected into the left ventricle. From the resting values (40 +/- 2 beats/min; 37.3 +/- 0.2 C), heart rate and pulmonary arterial blood temperature increased significantly at 5 (152 +/- 8 beats/min; 38.6 +/- 0.2 C), 15 (169 +/- 6 beats/min; 39.8 +/- 0.2 C), and 26 (186 +/- 8 beats/min; 40.8 +/- 0.2 C) minutes of exertion, and the ponies sweated profusely. Mean aortic pressure also increased progr...
Pérez R, Recabarren SE, Mora G, Jara C, Quijada G, Hetz E.In order to establish the relationship between draught force and cardiorespiratory responses to exercise heart rate (HR), respiratory rate (RR), arterial and venous blood gases, pH, hemoglobin concentration and temperature were measured in five draught horses during rest, immediately after exercise and 30 min post-exercise under field conditions. A wagon equipped with an odometer and a hydraulic dynamometer was used for measuring distance and draught force. The wagon was loaded with 946 kg for the low load, 1,979 kg for the medium load and 2,994 kg for the high load, and drawn for a distance o...
Mogg KC, Pollitt CC.Forelimb surface temperatures were continuously monitored in four clinically normal ponies exposed to: (i) constant ambient temperature; (ii) a biphasic change in ambient temperature; and (iii) an incremental increase in ambient temperature. Limb surface temperatures were recorded at the hoof, metacarpus and forearm, and rectal temperature was also measured. Under constant ambient temperature, limb surface temperatures remained relatively constant. A pyrexic episode occurred in one pony under constant ambient temperature conditions and was characterised by an onset phase in which rectal temper...
Wahdati A, Lindner A, Sommer H.The influence of temperature and duration of storage on glutathione peroxidase (GSH-Px) activity in plasma and whole blood samples of horses was investigated. Furthermore the relationships between the GSH-Px activities in plasma and whole blood as well as the GSH-Px values related to hematocrit and the hemoglobin content of the blood samples of 93 different horses were calculated. At 20-22 degrees C, the GSH-Px activity in plasma and whole blood samples remained stable over at least three days while it was reduced by 38% and 65% after 2 and 3 days, if the whole blood samples were kept stored a...
Morozova L, Haezebrouck P, Van Cauwelaert F.The thermal denaturation of Ca(2+)- and apo-forms of equine lysozyme was followed by using far and near UV circular dichroism and intrinsic fluorescence methods. The difference found between the temperature dependence of the ellipticity at 222 nm and 287 nm, which show two stages in the thermal transition, and those at 228 nm and 294 nm, which indicate only one stage over a wide range of temperatures reflects that different subdivisions of the protein molecule are characterized by a different stability, cooperativity and pathway of denaturation. The first transition, reflected in the increase ...
Fedde MR.Correction factors have been determined to obtain the best estimates of PO2, PCO2 and pH in equine blood with standard blood gas and pH electrodes. There was a significant difference between the PO2 readings for tonometred blood of most horses and the equilibrating gas. Thus, if the PO2 electrode is calibrated with a gas, an electrode correction factor should be obtained by tonometring a blood sample from each horse. This factor was not dependent on packed cell volume. No such correction is required for the PCO2 electrode. If the animal's temperature differs from that of the analyser, the PO2,...
Van den Berg JS.Clinically normal horses (n = 8) with ages ranging from 5 to 8 years, were starved for 12 h and their plasma ammonia concentrations were measured. The mean fasting plasma ammonia concentration was 17.8 +/- 3.8 mumol l-1. After dosing ammonium chloride at a dose rate of 0.02 g kg-1, there was a significant increase in plasma ammonia concentration, with a maximum rise after 20 min (P less than 0.05). To investigate the influence of temperature on plasma ammonia concentrations of stored samples, 8 plasma samples were stored at -20 degrees C and 4 degrees C respectively. The plasma ammonia concent...
Martel P, Calmettes P, Hennion B.Equine red blood cells were washed in saline heavy water (2H2O) to exchange the hydrogen atoms of the non-hemoglobin components with deuterons. This led to novel neutron scattering measurements of protein vibrations within a cellular system and permitted a comparison with inelastic neutron scattering measurements on purified horse hemoglobin, either dry or wetted with 2H2O. As a function of wavevector transfer Q and the frequency transfer v the neutron response typified by the dynamic structure factor S(Q, v) was found to be similar for extracted and cellular hemoglobin at low and high tempera...
Bagy MM, Abdel-Mallek AY.Nine thermophilic genera and 17 species in addition to one variety of Aspergillus flavus, Malbranchea pulchella and Humicola grisea were collected from hair samples in Riyadh, Saudi Arabia at 45 degrees C. Fifty-one hair specimens of rabbit, sheep, camel and horse were examined for the presence of thermophilic fungi. The most frequent species were Aspergillus fumigatus, Aspergillus niger, Thermoascus aurantiacus and Malbranchea pulchella var. sulfurea. In low frequency, Aspergillus flavus, Aspergillus quadrilineatus, Paecilomyces variotii, Paecilomyces aerugineus, Mucor pusillus and Rhizopus s...
Freidman R, Scott M, Heath SE, Hughes JP, Daels PF, Tran TQ.Stallions can experience an increase in testicular temperature from bouts of fever or from injury to the testes. In species other than the horse, increased temperature models have been used to study testicular degeneration. This study was undertaken to examine the effects of increased testicular temperature on spermatogenesis in the stallion as measured by semen evaluation. The results of this investigation demonstrate that increased testicular temperature is associated with significant transitory alterations in the routine semen evaluation of the stallion. The duration of increased testicular...
Ousey JC, McArthur AJ, Rossdale PD.Metabolic rates, rectal temperatures and respiratory quotients (RQ) were determined during the first 24 h post partum in Thoroughbred and pony foals and in relation to environmental temperature. Both breeds had high metabolic rates (greater than 200 W/m2) during the first hour post partum when they were wet and shivering; by 4 to 24 h values were fairly steady at about 153 and 105 W/m2 for Thoroughbred and pony foals, respectively. At birth, rectal temperature was lower in Thoroughbred foals than in pony foals; values increased during the first hour, and then decreased. At 24 h of age, both br...
Flisińska-Bojanowska A, Gill J, Komosa M.1. The diurnal changes in the levels of lactic (LA) and pyruvic (PA) acids and values of pH were studied in standard-bred mares and their foals, for 13 weeks of foal life, throughout 2 years. 2. The studies began when a foal was 7 days old and were repeated every 2 weeks until foals reached 13 weeks of age. 3. Blood samples were taken every 4 hr for one day, each second week. 4. In the LA, PA levels and pH values no diurnal rhythm was stated in lactating mares during study periods. 5. In foals the diurnal rhythm in LA and PA occurred in the 3rd month of their life, with the acrophase at night ...
Ekfalck A, Rodriguez-Martinez H, Obel N.Explants from the matrix of the stratum medium of the wall of the equine and bovine hoof each were cultured on a microporous membrane, using a standard culture medium. After incubation at 37 C, the outgrowth was a mixture of keratinocytes and fibroblasts, with predominance of the latter. After incubation at 34 C, the keratinocytes dominated, covering the lateral surfaces of the explant as well as the basal surface. Lateral outgrowth of keratinocytes was observed at the borderline of the original epidermis and at the borderline of the explant's contact with the membrane. Epithelial outgrowth fr...
Cymbaluk NF.Housing temperature effects on growth, feed utilization and feed digestion of 12, 7-mo-old Standardbred colts were evaluated for 22 wk beginning in late November. Colts were assigned to one of two treatments: housed in a barn heated at 10 degrees C (warm) or housed in a barn with no external heat supply (cold). All horses were allowed outdoors for 4 h daily. Mean temperatures of the warm and cold barn from November to April were 10.9 +/- .66 and -5.2 +/- 1.72 degrees C, respectively. Hair coat weight of cold-housed colts was 1.4- to twofold (P less than .05) that of warm-housed colts from Dece...
Hodgson DR, Rose RJ, Kelso TB, McCutcheon LJ, Bayly WM, Gollnick PD.Thoroughbred horses were exercised to fatigue on a treadmill at 62% and 100% of their VO2max. Hypoxemia occurred at the onset of exercise under both exercise conditions. This hypoxemia persisted to fatigue during the heavy exercise but progressively diminished as the exercise continued and had disappeared by the end of exercise at the lighter load. As a result of the hypoxemia the oxygen content of arterial blood during exercise at VO2max was 17% below its carrying capacity. However, under both experimental conditions the CaO2 still exceeded that of rest owing to an elevation in hemoglobin con...
Floris B, Bini PP, Nuvole P, Di Meglio FG.The changes of some parameters in the blood serum of six Giara horses (3 males and 3 females) were checked weekly, in relation to the environmental temperature throughout a one winter and summer. T3, total lipids, triglycerides, urea nitrogen, creatinine, total protein, albumin, beta and gamma globulin showed significant difference between winter and summer and, with the exception of triglycerides, urea nitrogen and total protein were correlated to the environmental temperature. T4, glucose, uric acid and alpha globulin showed no difference between the two seasons and no correlation with the t...
Sukhova GS, Ignat'ev DA, Akhremenko AK, Levashova VG, Mikhaleva II, Sviriaev VI, Anufriev AI, Ziganshin RKh, Kramarova LI, Gnutov DIu.From tissues of hibernating and active long-tailed ground squirrels and from the brain of cold-adapted Yakut horses, low molecular peptide fractions were obtained which, after injection to albino mice, decreased oxygen consumption and rectal temperature in them. The same fractions exhibited negative chrono- and inotropic effects on isolated hearts of ectothermic and endothermic animals. Fractions from the brain of ground squirrels and the brain of horse exhibited similar pattern of the activity. The activity of fractions was subjected to seasonal changes and depended on the degree of their pur...
Nequin LG, King SS, Matt KS, Jurak RC.The transition from anoestrus to oestrus in mares is controlled by photoperiod. The present study examined whether additional daylength would accelerate the mares' response to gonadotrophin-releasing-hormone (GnRH). Nine anoestrous mares were placed under ambient or artificial long lighting on 7th January. The four month experimental period was divided into a three-day sequence which was repeated at 21 day intervals. Ovaries were palpated rectally on Day 1; saline was injected (1 ml intravenously [iv]) on Day 2; GnRH was administered (0.59 microgram/kg bodyweight iv) on Day 3. Blood was taken ...
Cymbaluk NF, Christison GI.Horses are reared in all types of weather. Temperatures as diverse as -40 degrees C to 40 degrees C are tolerated by horses. The nutrient requirement most influenced by cold weather is energy. In cold weather, feeding good quality hays free-choice is usually sufficient for mature horses in good body condition. Grain may have to be fed when poor quality hays are used. Hot weather (greater than 30 degrees C) necessitates heat loss to maintain body core temperature. Horses sweat to reduce body heat. Heat stress can be minimized by feeding diets that reduce the heat increment. Use of grain and fat...
Lindner A, Will Y, Wilkniss E, Chrispeels J.The influence of duration and temperature of storage on hormone levels of whole blood, plasma and serum of horses was investigated. Using FPIAs cortisol, T4 and T-uptake could be measured while the T3-FPIA did not work appropriately. Serum and Plasma stored under the same conditions did not show any difference in cortisol, T4 and T-uptake values. In frozen heparinized plasma samples analysed on different days the cortisol and T4 concentrations fluctuated markedly. The T-uptake values were rather stable. The smallest day by day changes of cortisol and T4 in plasma were found when storing the sa...
Goetz TE, Manohar M.The heart rate (HR) induced by maximal beta-adrenergic activation, which was elicited by infusion of isoproterenol, was studied in 8 healthy horses before (control) and after hyperthermia was induced by IV administration of 2,4-dinitrophenol (DNP). Isoproterenol was administered IV at 1.0 micrograms.kg-1.min-1 for 3 minutes, and the HR was determined during the final 30 seconds of the infusion. As the rectal temperature increased (P less than 0.001) from 38.2 +/- 0.1 C (mean +/- SEM; normothermic control) to 40.1 +/- 0.1 C at 60 minutes after DNP administration, the isoproterenol-induced HR al...
Manohar M.Tracheobronchial circulation during exercise has previously not been examined. Therefore blood flow to the trachea and bronchi (up to 7th generation of branching) was studied in seven healthy adult ponies at rest and during the 3rd and 10th min of exercise performed at a treadmill speed setting of 25 km/h. The ambient air temperature varied from 19 to 20 degrees C and humidity from 35 to 45%. To determine blood flow radionuclide-labeled 15-microns-diameter microspheres were injected into the left ventricle via a catheter advanced from the left carotid artery (exposed using local anesthesia), a...
Jacob RJ, Price R, Bouchey D, Davis T, Borchelt J.This article reviews the findings on temperature sensitivity of equine herpesvirus isolates with an emphasis on equine herpesvirus 3, etiological agent of equine coital exanthema. The hypothesis is presented that the relative apathogenic nature of this herpesvirus may be an indirect result of its inability to synthesize and/or process glycoproteins needed by the virus to produce infectious virions at the normal body temperature of its natural host. It is suggested that equine herpesvirus 3 is the more evolved and naturally attenuated member of the equine herpesviruses.
McCarthy RN, Jeffcott LB, McCartney RN.Ultrasound speed, as measured by a transmission technique in equine cortical bone, was found to vary markedly with the direction of the ultrasound path through the bone. Using bone samples from the mid-site of the third metacarpus of 20 horses, the ultrasound speed was measured as 4125 m s-1 in the longitudinal direction, 3442 m s-1 in the circumferential or transverse direction, and 3428 m s-1 in the radial direction. These results confirm the anisotropic properties of compact bone. Ultrasound speed had a positive linear relationship when compared with bone specific gravity of cortical bone (...
Palmer SE.Evaluation was made of the portable infrared thermometer to measure limb surface temperature in 3 horses--first standing in a stall and then placed in lateral recumbency under general anesthesia. To determine the effect of pigment, black and white targets were examined with the instrument under various clinical conditions. In each horse, thermal gradient measurements were consistent along the extremities. Mean limb surface temperatures were less than rectal temperature and greater than ambient temperature. Limb surface temperatures measured in lateral recumbency under general anesthesia were u...
Jansson A, Nyman S, Morgan K, Palmgren-Karlsson C, Lindholm A, Dahlborn K.In this study 4 Standardbred geldings (age 3-8 years, weight 431-531 kg) were used. The horses were fed a hay and oat diet and the total sodium intake was about 32 mg/kg bwt (690 mmol/day). An exercise test (ET) which contained 3 phases was performed. Phase I consisted of 23.5 min of mainly submaximal exercise, Phase 2 of 2 h of box rest and Phase 3 of 26 min of exercise including an intensive trot over 2600 m at 90% of VO2max. The ET was repeated 3 times: the first at 20 degrees C (30-40% RH), the second at 35 degrees C (30-40% RH) and the third at 35 degrees C (30-40% RH) after a nasogastric...
Warner A, Mayhew IG.Anhidrosis is loss of the ability to sweat. The problem is seen in horses kept in a hot humid climate, and it may cause severe impairment of thermoregulation in the equine athlete. British Thoroughbreds imported to her tropical colonies are the earliest recorded cases, and since then the syndrome has come to be described as one of Thoroughbreds, usually performance athletes, undergoing acclimatization to heat and humidity. A recent epidemiologic study of cases in Florida has shown, however, that many different breeds, and long time inhabitants of a hot climate, may be affected. Equine sweat gl...
Marr CM, Bright JM, Marlin DJ, Harris PA, Roberts CA.We hypothesised that exercise in a hot and humid environment would affect echocardiographic indices of cardiac dimensions and function more than exercise in a cool environment. M-mode echocardiograms were obtained in 5 clinically normal horses before, and at 0, 10, 30 and 60 min after a treadmill exercise test. The test was performed in a controlled environment at 20 degrees C/40% relative humidity (RH) and again at 30 degrees C/80% RH. All the horses completed the exercise test in cool conditions, but only one horse completed the exercise test in the hot/humid environment. The relaxation time...
Pascoe DR, Stabenfeldt GH, Hughes JP, Kindahl H.Thirty mares with normal estrous cycles were allotted equally to 5 groups and infused with 250 ml of saline (NaCl) solution in utero on the seventh day after ovulation to test the effects of temperature, osmolarity, or pH of the saline solution on prostaglandin F2 alpha (PGF2 alpha) release and luteolysis. Intrauterine infusion of phosphate-buffered saline solution failed to alter the duration of the luteal phase, compared with the control group. Similarly, increasing the temperature of phosphate-buffered saline solution to 42 C or increasing (600 mosm) or decreasing osmolarity (less than 10 m...
Wesson JA, Ginther OJ.Thirteen 6-8 month-old fillies were assigned to 3 treatment groups: Group 1 had a 16-h fixed daily photoperiod (16L:8D, N = 4), Group 2 a daily photoperiod equivalent to ambient daylength (control, N = 5), and Group 3 a 9-h fixed daily photoperiod (9L:15D, N = 4). The light treatments extended from 17 December to 9 August. Hair shedding occurred first in Group 1 followed by Group 2, then Group 3. The proportions of fillies with 1 or more ovulations (puberty) by the end of the project were 2/4, 5/5, 2/4 in Groups 1, 2 and 3, respectively. The hypothesis that a fixed daily photoperiod which corr...
Albrizio M, Lacalandra GM, Volpe S, Nicassio M, Cinone M.Heat Shock Proteins are chaperones primary involved in the repair of cellular damages induced by temperature. The harmful effect of temperature on the male gonad is well known, on the contrary knowledge on the effects of the environment on semen quality are still insufficient. The aim of this paper was to learn more about the role of HSPs and the environment in modulating the physiology of equine male gonads. We showed a detailed analysis of equine semen characteristic and the expression level of three HSPs (60-70-90) over a one-year period analyzing the effects of temperature and humidity and...
Kagan IA.Temperate grasses contain both water- and ethanol-soluble carbohydrates. Water-soluble carbohydrates (WSCs) of temperate grasses include glucose, fructose, sucrose, and fructans (fructose-based polymers) of varying lengths. Ethanol-soluble carbohydrates (ESCs) consist of glucose, fructose, sucrose, and shorter fructans. WSCs and ESCs have been implicated in equine pasture-associated laminitis and other metabolic disorders. In this paper, the peer-reviewed literature of the past decade was summarized for selected factors influencing concentrations and composition of WSCs and ESCs in temperate g...
Jenkinson DM, Loney C, Elder HY, Montgomery I, Mason DK.Histological studies of the sweat glands of anhidrotic horses in the Hong Kong summer and under conditions of reduced thermal stress, both natural and controlled, were undertaken to determine if glandular regeneration occurs. Clinical data were collected for comparison with the histological results in each instance. Horses were assigned to one of three categories on the basis of the resulting change in the number of thin glandular profiles in a cooler environment. Group 1, which was classed as normal, had a low initial value, which was maintained. Group 2, typical of mild and moderately affect...
Joongpan W, Tongsangiam P, Poochipakorn C, Charoenchanikran P, Chanda M.Horses were provided full-time housing in unfamiliar vector-protected facilities during the African horse sickness (AHS) outbreak in Thailand. This study aimed to investigate the impact of this housing arrangement on the equine stress response. Nine healthy horses were housed in both a traditional barn and a vector-protected barn. Equine behavior and stress response data were collected in association with the housing environment and time of day. The mean behavioral score of horses housed in the vector-protected barn was lower at night than during the day. In addition, the horses' mean heart ra...
Jacobs CC, O'Neil E, Prange T.To determine the ability of a commercial cryotherapy system (Game Ready Equine) to cool the metacarpal subcutaneous tissue and the superficial digital flexor tendon (SDFT) in horses. Methods: Experimental study. Methods: Six healthy adult horses. Methods: Thermocouples were implanted into the metacarpal subcutaneous tissues and the SDFT of six horses. Two treatments (cryotherapy or cryotherapy with 5-50 mmHg intermittent compression) were randomly assigned to forelimbs and performed for 20 minutes. Temperatures were compared to the target range of 10-19°C and between groups. Results: Only...
Frohlich M, Knights K, Springer NL.Differentiating immune-mediated causes from other causes of anemia and thrombocytopenia can be challenging. Flow cytometry can detect surface-associated immunoglobulin (sIg) on red blood cells (RBC) and platelets (PLT) in dogs and horses. Sample storage parameters for ideal assay performance has not been evaluated in horses. The study objective is to identify optimal storage time and temperature of equine whole blood for the detection of RBC-sIg and PLT-sIg via flow cytometry. Both assays were performed on samples at time 0, 4, 24, 48, and 72 h post collection. RBC-sIg samples were stored at ...
Jacob RJ, Steiner MR.Equine herpesvirus 3 (EHV-3)-infected equine cells display a kinetics of infected cell polypeptide (ICP) synthesis at 34 degrees C that is typical of coordinate cascade gene regulation of herpesviruses. In contrast, when infected cell cultures are incubated at the restricted temperature of 39 degrees C, the shift from early (beta) gene expression to late (gamma) gene expression is perturbed, i.e., there is an accumulation of early (beta) gene products and a decrease in, or absence of, late (gamma) gene products. Some of the affected late (gamma) gene products may be glycoproteins since these I...
Kubota T, Inaba Y, Uwatoko K, Akashi H, Fukunaga Y.Equine arteritis virus (EAV) grown on RK13 cell cultures was tested for hemagglutination (HA) with erythrocytes from a variety of species at 4 degrees C, room temperature and 37 degrees C. HA was observed at all temperatures with erythrocytes from mouse and chicken but not with those of cattle, horse, rabbit, guinea pig, mongolian gerbil, goose or chick embryo. Chickens showed an individual variation in agglutinability of their erythrocytes, requiring selection of birds to obtain erythrocytes for HA. The HA activity was enhanced by treatment of virus materials with Tween 80 followed by treatme...
Zaha C, Schuszler L, Dascalu R, Nistor P, Florea T, Imre K, Rujescu C, Sicoe B, Igna C.Horses with palmar foot pain do not show a typical increase in temperature in the palmar aspect of the hoof and heel due to low blood flow. The objectives of the current study were to determine the changes and differences in the thermographic pattern of the sole surface in horses with unilateral palmar foot pain and non-lame horses before and after training. We hypothesized that the thermal pattern and the local temperature of the frog area and toe area would be similar, with an increased local temperature after training in both lame and non-lame horses. A pilot study was conducted to investig...
O' Brien C, Pegg J.This observational study aimed to elucidate the effects of RWST on the cardiovascular and musculoskeletal systems of horses and concurrently determine whether RWST limits distal limb temperature increases previously reported during gallop training on land. A group of 15 clinically sound international event horses were recruited, and heart rate (HR), speed (km/h) and thermal images of the distal limb were analysed at set intervals during RWST training. Intervals of RWST produced a total mean HR value of 65.18 ± 3.76%, which is within the parameters for increased aerobic stamina. Mean HR increa...
Casella S, Piccione D, Ielati S, Bocchino EG, Piccione G.The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome-citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incuba...
Rua MAS, Quirino CR, Rodrigues ACC, Christo MM, Barreto MAP.The objective of this study was to evaluate the environmental effects on embryo recovery rate and pregnancy rate of Mangalarga Marchador mares. The reproductive characteristics of donor and recipient mares were evaluated during five years in Brazilian tropical environment. The mares were used throughout the year and seasons were classified as: October to April (breeding season - BS); May (autumn transition out of the breeding season - ATBS); June to August (non-breeding season - nBS); and September (vernal transition into the breeding season - VTBS). Daily temperature rainfall and hours of day...
Hope E, Johnston SD, Hegstad RL, Geor RJ, Murphy MJ.A commercially available radioimmunoassay kit for measurement of human osteocalcin was validated for use in horses. For accurate measurement of equine serum osteocalcin, blood samples may be collected at a temperature between 20 and 25 C, then centrifuged within 90 minutes; serum may be stored at -20 C in plastic tubes for up to 26 weeks. Serum may be thawed and refrozen up to 5 times without significant change in measured equine serum osteocalcin concentration. Assay sensitivity was 0.16 ng/ml. Recovery of bovine osteocalcin standard added to equine serum was linear. Intra-assay coefficient o...
Bowers S, Gandy S, Anderson B, Ryan P, Willard S.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...
Hammer C, Gunkelman M.The objective of this study was to examine changes in surface temperature of blanketed horses during cold weather. Four mature stock-type horses were used in a 4 × 4 Latin square design. Treatments included 3 different blanket weights (based on g of fiberfill): light weight (LW; 0 g), medium weight (MW; 200 g), heavy weight (HW; 400 g), and a nonblanketed control (CON). Thermographic images were obtained from a standardized lumbar location before blanketing and immediately after cold exposure. During cold exposure, horses were outside with ad libitum access to grass hay and water for 1 h...
Floris B, Bini PP, Nuvole P, Di Meglio FG.The changes of some parameters in the blood serum of six Giara horses (3 males and 3 females) were checked weekly, in relation to the environmental temperature throughout a one winter and summer. T3, total lipids, triglycerides, urea nitrogen, creatinine, total protein, albumin, beta and gamma globulin showed significant difference between winter and summer and, with the exception of triglycerides, urea nitrogen and total protein were correlated to the environmental temperature. T4, glucose, uric acid and alpha globulin showed no difference between the two seasons and no correlation with the t...
Pain R, Sneddon JC, Cochrane CA.Franz diffusion cells containing uniformly dehydrated equine blood clots to simulate fibrinous eschar were used to measure the rate of debridement of fibrin by novel and traditional wound dressings, under standardised conditions of temperature, pH and humidity. Significant increases in protein breakdown occurred within 24 hours with all the dressings, but not thereafter. In general, dressings hydrated in normal saline were better as debriding agents than dressings hydrated in water. Autolytic debriding agents were 47 per cent more effective than chemical debriding agents; specifically, hydrofi...
Adrian AM, Koene M, Roberts S, Doughty P, Bolas N, Kinns J, Brehm W, Gerlach K.The extent of fat suppression using short tau inversion recovery (STIR) imaging is variable between horses. Our aim was to determine if patient's age and/or hoof temperature have an influence on the T(1) relaxation time of bone marrow in the equine distal limb, thereby affecting the suppression of fat signal. Magnetic resonance imaging was conducted on standing horses and cadaver samples using a low-field magnet (0.27 T). The hoof temperature was measured at the lateral side of the coronary band. A modified inversion recovery fast spin-echo (IR-FSE) sequence was used to measure the signal inte...
Page P, Ganswindt A, Schoeman J, Venter G, Guthrie A.African horse sickness (AHS) is of importance to health and international trade in horses worldwide. During export from and transit through AHS endemic countries or zones, physical and chemical measures to protect horses from the vectors of AHS virus (AHSV) are recommended by the World Organization for Animal Health. Protection of containerized air transport systems for horses (jet stalls) with alphacypermethrin insecticide-treated high density polyethylene mesh is effective in reducing the Culicoides midge vector attack rate. In order to determine the effect of this mesh on jet stall ventilat...
Monkos K.This paper presents the results of viscosity determinations on aqueous solutions of equine, porcine and rabbit serum albumin over a wide range of concentrations and at temperatures ranging from 5 degrees C to (42-45) degrees C. The results are compared with human and bovine serum albumin previously studied. Viscosity-temperature dependence is discussed on the basis of the modified Arrhenius formula. The effective specific volume, the activation energy and entropy of viscous flow for all investigated albumins are compared. Viscosity-concentration dependence, in turn, is discussed on the basis o...
Province CA, Amann RP, Pickett BW, Squires EL.Two experiments were conducted to evaluate the effects of six extenders and three glycerol levels on the motility of sperm stored at 5 degrees C. Using a split-ejaculated design, semen from 10 dogs and 12 stallions was extended with egg-yolk-tris (EYT), egg-yolk-bicarbonate (EGB), Beltsville F-3 (BF-3), Cornell University (CUE), caprogen (CAP) and heated skim milk (SM) extenders. After cooling to 5 degrees C, additional extender containing 0% to 12% glycerol was added to provide a final concentration of 0%, 3% or 6% glycerol. Regardless of glycerol level, a higher (P<0.05) percentage of can...
Scott CM, Marlin DJ, Schroter RC.Previously we have observed a decline in sweating rate (SR) during high intensity exercise in an incremental test protocol. In man, the sweating sensitivity (SR/degree C) has been shown to vary with exercise intensity. The aim of the present study was to determine if thermoregulatory responses in the horse, a prolific sweater with a high rate of metabolic heat production, were modified by exercise intensity. The effect of 3 separate exercise intensities (50 (S), 70 (M) and 90% (F) VO2peak on neck (SRN) and gluteal sweating rate (SRG), pulmonary artery (TPA), rectal (TREC) and skin temperatures...
Wahdati A, Lindner A, Sommer H.The influence of temperature and duration of storage on glutathione peroxidase (GSH-Px) activity in plasma and whole blood samples of horses was investigated. Furthermore the relationships between the GSH-Px activities in plasma and whole blood as well as the GSH-Px values related to hematocrit and the hemoglobin content of the blood samples of 93 different horses were calculated. At 20-22 degrees C, the GSH-Px activity in plasma and whole blood samples remained stable over at least three days while it was reduced by 38% and 65% after 2 and 3 days, if the whole blood samples were kept stored a...
Jacobi S, Townsend WM, Bolin CA.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...
