The physiology of horses encompasses the study of the biological functions and processes that occur within the equine body. This includes the examination of various systems such as the cardiovascular, respiratory, musculoskeletal, digestive, and nervous systems. Understanding equine physiology is essential for comprehending how horses adapt to different environmental conditions, perform physical activities, and respond to health challenges. Research in this field often focuses on the mechanisms of energy metabolism, thermoregulation, and muscle function during exercise, as well as the physiological responses to stress and disease. This page compiles peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine physiology, providing insights into the biological processes that support the health and performance of horses.
Cortés-Gutiérrez EI, Dávila-Rodríguez MI, López-Fernández C, Fernández JL, Crespo F, Gosálvez J.The presence of constitutive alkali-labile sites (ALS) has been investigated using a protocol of DNA breakage detection-fluorescence in situ hybridization and comet assay in spermatozoa of donkey (Equus asinus) and stallion (Equus caballus). These results were compared with those obtained using a similar experimental approach using somatic cells. The relative abundance of ALS was of the order of four times more in spermatozoa than in somatic cells. Alkali-labile sites showed a tendency to cluster localized at the equatorial-distal regions of the sperm. The amount of hybridized signal in the AL...
Hartwig FP, Lisboa FP, Hartwig FP, Monteiro GA, Maziero RR, Freitas-Dell'Aqua CP, Alvarenga MA, Papa FO, Dell'Aqua JA.During the cooling process, sperm may suffer irreversible damage that compromises the fertility rate. Incorporating cholesterol-loaded cyclodextrin (CLC) represents a strategy to increase sperm resistance at low temperatures; however, high levels of cholesterol in the cell membrane can interfere with sperm capacitation. The goals of this study were to determine the CLC concentration and cooling temperature that produce optimal kinetic parameters and viability of sperm from stallions identified as bad coolers (BCs) and good coolers (GCs), as well as the effect of adding CLC on the occurrence of...
Ringer SK, Schwarzwald CC, Portier K, Mauch J, Ritter A, Bettschart-Wolfensberger R.The aim of the present study was to investigate changes in blood glucose concentration ([Glu]B), acid-base status and electrolyte concentrations during constant rate infusions (CRI) of two alpha2-adrenergic agonists in seven horses treated in a blinded, randomised, crossover design with xylazine or romifidine. An intravenous (IV) bolus of xylazine (1mg/kg) or romifidine (80 μg/kg) was administered followed by an IV CRI of xylazine (0.69 mg/kg/h) or romifidine (30 μg/kg/h) for 2h. Blood samples were collected from the pulmonary artery before and after loading doses, during the CRI, and for 1h...
de Graaf-Roelfsema E.One of the principal components of equine metabolic syndrome (EMS) is hyperinsulinaemia combined with insulin resistance. It has long been known that hyperinsulinaemia occurs after the development of insulin resistance. But it is also known that hyperinsulinaemia itself can induce insulin resistance and obesity and might play a key role in the development of metabolic syndrome. This review focuses on the physiology of glucose and insulin metabolism and the pathophysiological mechanisms in glucose homeostasis in the horse (compared with what is already known in humans) in order to gain insight ...
Biddle AS, Black SJ, Blanchard JL.Laminitis is a chronic, crippling disease triggered by the sudden influx of dietary starch. Starch reaches the hindgut resulting in enrichment of lactic acid bacteria, lactate accumulation, and acidification of the gut contents. Bacterial products enter the bloodstream and precipitate systemic inflammation. Hindgut lactate levels are normally low because specific bacterial groups convert lactate to short chain fatty acids. Why this mechanism fails when lactate levels rapidly rise, and why some hindgut communities can recover is unknown. Fecal samples from three adult horses eating identical di...
Benhajali H, Ezzaouia M, Lunel C, Charfi F, Hausberger M.Discomfort in farm animals may be induced by inappropriate types or timing of food supplies. Thus, time restriction of meals and lack of roughage have been shown to be one source of emergence of oral stereotypies and abnormal behaviour in horses which have evolved to eat high-fibre diets in small amounts over long periods of time. This feeding pattern is often altered in domestic environment where horses are often fed low fibre meals that can be rapidly consumed. This study aimed at determining the effect of the temporal pattern of feeding on reproductive efficiency of breeding mares, One hund...
Gozalo-Marcilla M, Hopster K, Gasthuys F, Krajewski AE, Schwarz A, Schauvliege S.To compare the effects of a constant rate infusion (CRI) of dexmedetomidine and morphine to those of morphine alone on the minimum end-tidal sevoflurane concentration necessary to prevent movement (MACNM ) in ponies. Methods: Prospective, randomized, crossover, 'blinded', experimental study. Methods: Five healthy adult gelding ponies were anaesthetized twice with a 3-week washout period. Methods: After induction of anaesthesia with sevoflurane in oxygen (via nasotracheal tube), the ponies were positioned on a surgical table (T0), and anaesthesia was maintained with sevoflurane (Fe'SEVO 2.5%) i...
Toishi Y, Tsunoda N, Tagami M, Hashimoto H, Kato F, Suzuki T, Nagaoka K, Watanabe G, Tokuyama S, Okuda K, Taya K.Evaluation of a new chemiluminescent enzyme immunoassay, the PATHFAST assay system (PATHFAST), for measurement of circulating progesterone in mares was performed. Five mares at the mid-luteal stage were administrated a single i.m. injection of prostaglandin F2α analog (PGF2α; cloprostenol 250 μg/ml), and then blood samples were collected from the jugular vein at 0, 15, 30 and 45 min, at one-hour intervals until 24 and at 48 hr via a catheter in the jugular vein. To monitor the physiological changes in circulating progesterone in mares after induced luteolysis, concentrations of progesterone...
Couppé C, Svensson RB, Sødring-Elbrønd V, Hansen P, Kjaer M, Magnusson SP.Magnetic resonance imaging (MRI) has commonly been applied to determine tendon cross-sectional area (CSA) and length either to measure structural changes or to normalize mechanical measurements to stress and strain. The ability to reproduce CSA measurements on MRI images has been reported, but the accuracy in relation to actual tendon dimensions has never been investigated. The purpose of this study was to compare tendon CSA measured by MRI with that measured in vitro with the mould casting technique. The knee of a horse was MRI-scanned with 1.5 and 3 tesla, and two examiners measured the pate...
Grosche A, Morton AJ, Graham AS, Polyak MM, Freeman DE.To determine the effect of large colon ischemia and reperfusion on concentrations of the inflammatory neutrophilic protein calprotectin and other clinicopathologic variables in jugular and colonic venous blood in horses. Methods: 6 healthy horses. Methods: Horses were anesthetized, and ischemia was induced for 1 hour followed by 4 hours of reperfusion in a segment of the pelvic flexure of the large colon. Blood samples were obtained before anesthesia, before induction of ischemia, 1 hour after the start of ischemia, and 1, 2, and 4 hours after the start of reperfusion from jugular veins and ve...
Nauwelaerts S, Malone SR, Clayton HM.This study used stabilographic analysis to measure and describe changes in stability during standing in foals from birth to 5 months of age. Stabilographic analysis was performed on newborn foals immediately after first suckling then daily until 1 week of age, weekly until 1 month of age and monthly until 5 months of age. Ground reaction force (GRF) data were collected for periods of 8s with the foal standing on one or two force plates recording at 1000 Hz. Stabilographic variables describing the amplitude, velocity and frequency of center of pressure (COP) movements were derived from the GRF ...
Nauwelaerts S, Aerts P, Clayton H.Spontaneous transitions from anti-phase to in-phase manual coordination are explained in the Haken model that describes the two preferred states as stable regions that work as attractors in a stability landscape. Switching between states coincides with a temporary loss of stability. Coordination variability is believed to be indicative of such a loss of stability. In this study, the hypothesis was tested that an increase in variability in the angle profiles of the joints responsible for the transition will precede the transition. A full gait analysis of four miniature horses transitioning from...
Rhodin M, Pfau T, Roepstorff L, Egenvall A.Lungeing is an important part of lameness examinations, since the circular path enforced during lungeing is thought to accentuate low grade lameness. However, during lungeing the movement of sound horses becomes naturally asymmetric, which may mimic lameness. Also, compensatory movements in the opposite half of the body may mimic lameness. The aim of this study was to objectively study the presence of circle-dependent and compensatory movement asymmetries in horses with induced lameness. Ten horses were trotted in a straight line and lunged in both directions on a hard surface. Lameness was in...
Hobbs SJ, Clayton HM.The aims of this study were to measure ground reaction forces (GRFs) of concurrently loaded limbs and to evaluate spatial relationships between the centre of pressure (COP) and centre of mass (COM) in trotting horses. Kinematic (120Hz) and GRF data were collected at trot from three trials of eight horses using four force plates (960 Hz). Forelimb and hind limb GRFs were measured, COP was calculated from the resultant vertical GRF vector and COM was calculated by summation of weighted segmental COMs. Peak total vertical force (19.3 ± 1.3N/kg at 45.1 ± 2.3% diagonal stance) coincided with zero...
Roepstorff L, Wiestner T, Weishaupt MA, Egenvall E.The aim of this study was to compare an inertial motion system (IMS) to an optical based locomotion analysis system measuring limb sagittal segment angles in horses at the walk and trot. The metatarsal/metacarpal bones of two horses (20 trials) were fitted with optical system markers and an IMS. Between the systems, measuring range of motion (ROM) of the sagittal metatarsal/metacarpal bone angles, the IMS measured higher ROM than the optical system (bias 1.6°; precision at 1.96 standard deviation 1.9°). The same angle data were used to assess inter-limb symmetry by calculating phase shift be...
Oosterlinck M, Hardeman LC, van der Meij BR, Veraa S, van der Kolk JH, Wijnberg ID, Pille F, Back W.Empirically, equine distal limb lameness is often linked to hoof imbalance. To objectively quantify dynamic toe-heel and medio-lateral hoof balance of the vertical ground reaction force in sound sport horses, seven Royal Dutch Sport Horses were led at the walk and trot over a dynamically calibrated pressure plate. Forelimb hoof prints were divided into a toe and heel region and a medial and lateral zone. Toe-heel and medio-lateral hoof balance of the vertical ground reaction force were calculated throughout the stance. Toe-heel balance was highly symmetrical between contralateral limbs at both...
Bartolomé E, Sánchez MJ, Molina A, Schaefer AL, Cervantes I, Valera M.The aims of this study were, first, to evaluate eye temperature (ET) with infrared thermography and heart rate (HR) to measure stress in horses during show jumping competitions and their relationship with competition results, and second, to evaluate the influence of different extrinsic and intrinsic factors of the horse on the stress measurements analysed. One hundred and seventy-three Spanish Sport Horses were analysed for ET and HR, and these measurements were taken 3 h before the competition, just after and 3 h after it. Two interval measurements were also assessed for each parameter. Posit...
Eisersiö M, Roepstorff L, Weishaupt MA, Egenvall A.The aim of this study was to investigate the behavioural response of horses to rein contact and the movement of the riders' hands through analysis of data from horses ridden at two different head and neck positions. It was hypothesised that the riders' hand movements and rein tension would generate behavioural responses from horses and that these responses would be more marked when horses were ridden 'on the bit' than when unrestrained. Data were collected from seven dressage horse/rider combinations at sitting trot on a high speed treadmill. Kinematics were recorded using a 12-camera, infrare...
Randall C, Bridges D, Guerri R, Nogues X, Puig L, Torres E, Mellibovsky L, Hoffseth K, Stalbaum T, Srikanth A, Weaver JC, Rosen S, Barnard H....A novel, hand-held Reference Point Indentation (RPI) instrument, measures how well the bone of living patients and large animals resists indentation. The results presented here are reported in terms of Bone Material Strength, which is a normalized measure of how well the bone resists indentation, and is inversely related to the indentation distance into the bone. We present examples of the instrument's use in: (1) laboratory experiments on bone, including experiments through a layer of soft tissue, (2) three human clinical trials, two ongoing in Barcelona and at the Mayo Clinic, and one comple...
Seminati E, Nardello F, Zamparo P, Ardigò LP, Faccioli N, Minetti AE.We hypothesized that, as occurring in cars, body structural asymmetries could generate asymmetry in the kinematics/dynamics of locomotion, ending up in a higher metabolic cost of transport, i.e. more 'fuel' needed to travel a given distance. Previous studies found the asymmetries in horses' body negatively correlated with galloping performance. In this investigation, we analyzed anatomical differences between the left and right lower limbs as a whole by performing 3D cross-correlation of Magnetic Resonance Images of 19 male runners, clustered as Untrained Runners, Occasional Runners and Skille...
Martig S, Lee PV, Anderson GA, Whitton RC.In racehorses, fatigue related subchondral bone injury leads to overt fracture or articular surface collapse and subsequent articular cartilage degeneration. We hypothesised that the fatigue behaviour of equine subchondral bone in compression follows a power law function similar to that observed in cortical and trabecular bone. We determined the fatigue life of equine metacarpal subchondral bone in-vitro and investigated the factors influencing initial bone stiffness. Subchondral bone specimens were loaded cyclically in compression [54MPa (n=6), 66MPa (n=6), 78MPa (n=5), and 90MPa (n=6)] until...
Derochette S, Franck T, Mouithys-Mickalad A, Ceusters J, Deby-Dupont G, Lejeune JP, Neven P, Serteyn D.In neutrophils (PMNs), superoxide anion (O2*-), the first reactive oxygen species (ROS) produced to kill pathogenic agents, is generated by NADPH oxidase, an enzymatic complex formed by the translocation of cytosolic subunits to the membrane flavocytochrome b558. In horses, excessive activation of PMNs is often associated with deadly pathologies and the modulation of their ROS production by acting on NADPH oxidase is a prime target to manage inflammation. We developed a cell-free assay to measure the activity of equine NADPH oxidase assembled in vitro, in order to test the effects of natural o...
Aleman M, Williams DC, Brosnan RJ, Nieto JE, Pickles KJ, Berger J, Lecouteur RA, Holliday TA, Madigan JE.Idiopathic headshaking (HSK) in horses is a distressing disorder in which the etiology and pathophysiology are unknown. Objective: Differences in sensory function of the trigeminal nerve exist between healthy and affected horses. Methods: Six healthy mature geldings and 6 mature geldings with idiopathic HSK. Methods: Prospective study. Sensory nerve action and somatosensory evoked potentials studies were performed. The stimulus site comprised the gingival mucosa dorsal to the maxillary canine. A pair of recording electrodes was placed along the sensory pathway of the trigeminal complex at the ...
Larsson J, Pilborg PH, Johansen M, Christophersen MT, Holte A, Roepstorff L, Olsen LH, Harrison AP.Few studies have investigated the physiological parameters of endurance horses in Scandinavia. Hence, this two race study has focused on the effects of endurance racing in terms of equine clinicopathological blood parameters, heart score, and fluid use. Race A involved 15 horses (120 km). Two pre- and one post-race blood samples were taken, body condition score was assessed in triplicate pre-race, and an ECG was used to determine heart score. Race B involved 16 horses (65-120 km). One pre- and two post-race blood samples were taken. For both races, horse data as well as fluid intake estima...
Ceusters JD, Mouithys-Mickalad AA, Franck TJ, Deby-Dupont GP, Derochette S, Serteyn DA.Horses are outstanding athletes, performing in many different disciplines involving different kinds of efforts and metabolic responses. Depending on exercise intensity, their skeletal muscle oxygenation decreases, and the reperfusion at cessation of the exercise can cause excessive production of free radicals. This study on cultured primary equine myoblasts investigated the effect of different kinds of anoxia/reoxygenation (A/R) on routine respiration, mitochondrial complex I specific activity and free radicals production. Our data revealed that short cycles of A/R caused a decrease of all the...
Hyldahl Laursen S, Andersen PH, Kjelgaard-Hansen M, Wiinberg B.There is a paucity of information about the analytical performance of thromboelastography (TEG) in horses, specifically concerning components of variation among different analytical methods. Such data may be obtained by nested analysis of repetitive standardized sampling of healthy individuals. Objective: The objectives were (1) to assess the relative susceptibility to sources of preanalytical variation in a highly standardized setting, (2) to directly compare and evaluate the observed analytical variation, and (3) to assess the applicability of population-based reference intervals. Methods: B...
Rodríguez AM, Ferrusola CO, García BM, Morrell JM, Martínez HR, Tapia JA, Peña FJ.Ejaculates from 7 stallions were split and simultaneously frozen in three different extenders, INRA 96 egg yolk glycerol, Ghent and the newly developed extender Caceres. After thawing, samples were evaluated for motility (CASA system) sperm membrane integrity and early membrane changes (YoPro-1/Eth staining), acrosome integrity (FICT-PNA), and mitochondrial membrane potential (JC-1) (flow cytometry). Samples frozen in Caceres extender consistently showed the best results in post-thaw motility (increases ranging from 11 to 17%, p<0.05) and velocity (p<0.05), membrane integrity (increases ...
Combes GB, Varner DD, Schroeder F, Burghardt RC, Blanchard TL.The aim of the present study was to investigate the cryoprotectant properties of cholesterol after incorporation into the plasma membranes of equine spermatozoa. A cholesterol-methyl-beta-cyclodextrin complex was used to alter sperm plasma membrane cholesterol content. Ejaculates from six stallions were centrifuged in a non-fat skimmed milk glucose-sucrose extender (MK) or a modified Tyrode's medium (TALP). The sperm pellets were resuspended in the appropriate extender with or without added cholesterol (0.125 mmol cholesterol-methyl-beta-cyclodextrin complex l(-1)) and incubated at 24 degrees ...
Mendoza FJ, Perez-Ecija RA, Toribio RE, Estepa JC.Reference intervals for thyroid hormones (TH) concentrations have not been previously established for donkeys, leading to potential misdiagnosis of thyroid disease. Objective: To determine the normal values of TH in healthy adult donkeys and compare them to TH values from healthy adult horses. Methods: Thirty-eight healthy Andalusian donkeys and 19 healthy Andalusian horses from 2 different farms were used. Donkeys were divided into 3 age groups: 11 years and into 2 gender groups. Serum concentrations of fT3, tT3, rT3, fT4 and tT4 were quantified by radioimmunoassay. All blood samples were col...
Zamboulis DE, Senior JM, Clegg PD, Gallagher JA, Carter SD, Milner PI.Purinergic pathways are considered important in pain transmission, and P2X receptors are a key part of this system which has received little attention in the horse. The aim of this study was to identify and characterise the distribution of P2X receptor subtypes in the equine digit and associated vasculature and nervous tissue, including peripheral nerves, dorsal root ganglia and cervical spinal cord, using PCR, Western blot analysis and immunohistochemistry. mRNA signal for most of the tested P2X receptor subunits (P2X1-5, 7) was detected in all sampled equine tissues, whereas P2X6 receptor su...
Kosinska MK, Eichner G, Schmitz G, Liebisch G, Steinmeyer J.The current limitations in evaluating synovial fluid (SF) components in health and disease and between species are due in part to the lack of data on normal SF, because of low availability of SF from healthy articular joints. Our study aimed to quantify species-dependent differences in phospholipid (PL) profiles of normal knee SF obtained from equine and human donors. Knee SF was obtained during autopsy by arthrocentesis from 15 and 13 joint-healthy human and equine donors, respectively. PL species extracted from SF were quantitated by mass spectrometry whereas ELISA determined apolipoprotein ...
Doherty TJ, Andrews FM, Provenza MK, Frazier DL.Gastric emptying was evaluated in ponies using the acetaminophen (AP) method. Fifteen minutes after i.v. administration of metoclopramide, erythromycin, yohimbine, atropine or saline, the ponies were given AP by stomach tube. Blood samples for AP analysis were collected at baseline and 15, 30, 45, 60, 75, 90, 105 and 120 min after AP administration. Time to reach peak serum concentration (Tmax), maximum serum concentration (Cmax) and area under the AP serum concentration vs. time curve (AUC) were determined for each treatment group. In the control group, Tmax was 31 min and this decreased sign...
Daels PF, Albrecht BA, Mohammed HO.The onset of eCG secretion in pregnant mares coincides with an increase in luteal steroid production and a relative shift toward androgen and estrogen synthesis. However, a cause-effect relationship between eCG and the shift in luteal steroidogenesis has not been demonstrated. In this study, we have investigated the effect of eCG on steroid production by the corpus luteum (CL) during equine pregnancy. All mares were supplemented with 44 mg altrenogest (a progestogen) per day on Days 18-50. Increasing doses of eCG were administered on Days 26-28, before the onset of endogenous eCG secretion, to...
Hobo S, Oikawa M, Kuwano A, Yoshida K, Yoshihara T.To study the effects of extended transportation on the composition of bronchoalveolar lavage fluid (BALF) obtained from horses. Methods: 30 horses (14 males, 16 females: 25 Thoroughbreds and 5 Thoroughbred-Arabian cross-breds; 27 to 30 months old) without a history or clinical signs of respiratory tract disease. Bronchoalveolar lavage was performed on nontransported control horses (groups 1 and 2) and transported horses (group 3). Methods: 20 horses were used to determine the effect of 41 hours of transportation on the composition of BALF (group 3). Bronchoalveolar lavage fluid was analyzed fo...
Álvarez R, Meléndez-Martínez AJ, Vicario IM, Alcalde MJ.Carotenoids are important for human health because of their provitamin A function among other biological actions. Their implication on consumer point of view of cattle products have been widely studied, but very little information is available for horse products. The aim of this study was to study the accumulation of carotenoids, retinoids and tocopherol by HPLC and HPLC-MS analysis in different horse tissues (plasma, milk, adipose tissue and liver) and compare it with that of cattle. Fat color was also studied. Four groups of animals were studied (15 animals within each group): lactating mare...
Edner A, Lindberg LG, Broström H, Bergh A.Static magnetic blankets are often claimed to induce increases in blood flow, reduce muscle tension and tenderness, and be beneficial in both prevention and treatment of musculoskeletal injuries in horses. However, there are no studies that confirm alleged beneficial effects of magnets on muscles of the back in healthy horses. Objective: To investigate whether static magnets sewn into a blanket affect back muscle blood flow, skin temperature, mechanical nociceptive threshold (MNT) and behaviour in healthy horses. Methods: Prospective, randomised, blinded, placebo-controlled crossover study. Me...
Sivaguru M, Eichorst JP, Durgam S, Fried GA, Stewart AA, Stewart MC.Injuries and damage to tendons plague both human and equine athletes. At the site of injuries, various cells congregate to repair and re-structure the collagen. Treatments for collagen injury range from simple procedures such as icing and pharmaceutical treatments to more complex surgeries and the implantation of stem cells. Regardless of the treatment, the level of mechanical stimulation incurred by the recovering tendon is crucial. However, for a given tendon injury, it is not known precisely how much of a load should be applied for an effective recovery. Both too much and too little loading...
Saudek V, Wormald MR, Williams RJ, Boyd J, Stefani M, Ramponi G.Nuclear magnetic resonance spectra of acylphosphatase were searched for signs of beta-structure, i.e. characteristic nuclear Overhauser enhancement patterns displayed in the two-dimensional spectra, typical chemical shifts, coupling constants and slow 2H-H exchange. The results provided identification of the main-chain resonances of amino acid residues involved in the beta-structure. The full sequential assignment of this region was gained by identification of some amino acid spin systems and their alignment with the primary sequence. The assignment of the side-chains was virtually completed s...
Nerren JR, Martens RJ, Payne S, Murrell J, Butler JL, Cohen ND.Although evidence exists that neutrophils play a vital role in resistance to infection with Rhodococcus equi, the means by which neutrophils exert their effects have not been clearly defined. In the present study we evaluated differences in cytokine expression by unstimulated and R. equi-stimulated neutrophils obtained from newborn foals and subsequently at 2-, 4-, and 8-weeks of age. Stimulation with virulent R. equi induced significantly (P<0.05) greater expression of IFNgamma, TNFalpha, IL-6, IL-8, IL-12p40, IL-12p35, and IL-23p19 mRNA relative to expression by unstimulated neutrophils, ...
Visser MB, Pollitt CC.The role of matrix metalloproteases (MMPs) and the timeline of proteolysis during laminitis development are incompletely understood. Objective: To determine the temporal progression of selected MMPs and protease regulators during laminitis development. Methods: Five clinically normal Standardbred horses received, via nasogastric intubation, an oligofructose (OF) bolus (10 g/kg bwt). Laminitis induction proceeded for 48 h followed by euthanasia. Lamellar biopsies were obtained prior to dosing and at intervals during the treatment period for analysis (12, 18, 24, 30 and 36 h and at 48 h followin...
Ross D, Marcot JD, Betteridge KJ, Nascone-Yoder N, Bailey CS, Sears KE.Tetrapod limb development has been studied extensively for decades, yet the strength and role of developmental constraints in this process remains unresolved. Mammals exhibit a particularly wide array of limb morphologies associated with various locomotion modes and behaviors, providing a useful system for identifying periods of developmental constraint and conserved developmental mechanisms or morphologies. In this study, landmark-based geometric morphometrics are used to investigate levels and patterns of morphological diversity (disparity) among the developing forelimbs of four mammals with...
Morel MC, Newcombe JR, Swindlehurst JC.Numerous and conflicting reports exist regarding factors that may effect mare reproductive performance, in particular multiple ovulation (MO) and its consequences. Sequential ultrasonic examination was used to monitor 3075 ovulations in 1581 mainly Thoroughbred mares to ascertain: whether increasing age is associated with an increase in MO; whether this is counteracted by an increase in embryo mortality (EM) prior to Day 13; and whether this embryonic loss may be associated with small-for-age embryonic vesicles (Days 13/14). Overall ovulation rate was 1.31, MO occurring in 29.3% of cycles. MO ...
Clark CK, Lester GD, Vetro T, Rice B.Bronchoalveolar lavage (BAL) was performed at weekly intervals in 10 Thoroughbred horses in race training (group 1) and in 4 rested horses (group 2) for 10 weeks. Lavages were continued on a weekly basis in 4 group 1 horses for an additional 9 weeks (group 3). Cytological analysis of samples included leukocyte counts, erythrocyte counts, differential leukocyte counts, and haemosiderophage score. The mean leukocyte concentration was significantly lower in group 1 (92.1 +/- 4.6 cells/microL) when compared with group 2 (133.5 +/- 8.2 cells/microL), P = 0.037. The differential leukocyte data were ...
Andrews FM, Buchanan BR, Elliott SB, Al Jassim RA, McGowan CM, Saxton AM.Volatile fatty acids, byproducts of carbohydrate fermentation by resident bacteria, have been implicated in causing nonglandular (NG) gastric ulcers. Lactic acid (LA), also produced by stomach bacteria, may cause gastric ulcers when exposed to the equine NG mucosa. Objective: To investigate the in vitro effects of LA on equine NG mucosa bioelectric properties, sodium transport and tissue resistance. Methods: Gastric tissues obtained from 13 mature horses were studied in Ussing chambers. Short-circuit current (Isc) and potential difference (PD) were measured, and electrical resistance (R) and c...
Grosche A, Morton AJ, Graham AS, Polyak MM, Freeman DE.To determine the effect of large colon ischemia and reperfusion on concentrations of the inflammatory neutrophilic protein calprotectin and other clinicopathologic variables in jugular and colonic venous blood in horses. Methods: 6 healthy horses. Methods: Horses were anesthetized, and ischemia was induced for 1 hour followed by 4 hours of reperfusion in a segment of the pelvic flexure of the large colon. Blood samples were obtained before anesthesia, before induction of ischemia, 1 hour after the start of ischemia, and 1, 2, and 4 hours after the start of reperfusion from jugular veins and ve...
Firląg M, Kamaszewski M, Gaca K, Bałasińska B.Aging is a process which operates at many levels of physiological, genetic and molecular organization and leads inevitably to death. Brain macroscopic changes by MRI investigation during aging were observed in humans and dogs but chimpanzees did not display significant changes. This suggestion led to the statement that brain aging is different in various species. Although human brain changes, e.g. β-amyloid storage, neurofibrillary tangle formation, lipofuscin, are relatively well known, we are still looking for a suitable animal model to study the mechanisms of aging and neurodegenerative di...
Berglund LA, Sharp DC, Vernon MW, Thatcher WW.Uterine flushings were obtained through the cervix (Method A) and through the wall of the uterus after hysterectomy (Method B) of ovariectomized Pony mares after s.c. injection of oestrogen for 1 week and progesterone for 2 weeks (Exp. 1). Non-pregnant and pregnant mares were flushed by Method A on Day 14 after ovulation and the flushings compared with those of non-pregnant mares injected i.v. with flunixen meglumine, a prostaglandin synthetase inhibitor, shortly before flushing (Exp. 3). Uterine flushings were also collected by Methods A and B from non-pregnant and pregnant Pony mares on Day ...
Dalla Costa E, Dai F, Lecchi C, Ambrogi F, Lebelt D, Stucke D, Ravasio G, Ceciliani F, Minero M.Pain in horses is an emergent welfare concern, and its assessment represents a challenge for equine clinicians. This study aimed at improving pain assessment in horses through a convergent validation of existing tools: we investigated whether an effective analgesic treatment influences the horse grimace scale (HGS) and the concentration of specific circulating microRNAs (miRNAs). Eleven stallions underwent routine surgical castration under general anaesthesia. They were divided into two analgesic treatment groups: castration with the administration of preoperative flunixin and castration with ...
Spriet M, Buerchler S, Trela JM, Hembrooke TA, Padgett KA, Rick MC, Vidal MA, Galuppo LD.To assess distribution, uptake, and persistence of radiolabeled mesenchymal stem cells (MSC) using scintigraphy after intravenous regional limb perfusion (RLP) and subcutaneous injections in standing, sedated horses. Methods: Experimental study. Methods: Horses (n = 12). Methods: Six horses had RLP performed through the cephalic vein on 1 limb and subcutaneous injection in the metacarpal area in the opposite limb. The other 6 horses had RLP performed through the lateral palmar digital vein and subcutaneous injection in the coronary band. A pneumatic tourniquet was used for the RLP. MSC were la...
Armstrong S, Lees P.Chondrocytes and synoviocytes harvested from the joints of healthy horses were maintained in tissue culture. Production of the cytokines interleukin-1 (IL-1), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) in response to lipopolysaccharide (LPS), and the effects of addition of carprofen (racemate and R and S enantiomers) were determined. Lipopolysaccharide failed to stimulate TNF-alpha activity in both cell types but concentrations of IL-1 and IL-6 were both increased in a concentration and time-related manner. Both carprofen enantiomers and the racemic mixture attenuated th...
Zak A, Siwinska N, Elzinga S, Barker VD, Stefaniak T, Schanbacher BJ, Place NJ, Niedzwiedz A, Adams AA.Age, neurodegenerative disorders, and dysfunction of insulin secretion may be correlated with increased systemic concentrations of acute phase markers. Thus, the study aimed to determine the effect of age, pituitary pars intermedia dysfunction (PPID), and insulin dysregulation (ID) associated with PPID, on markers of the acute phase reaction. Twenty-nine mix-breed horses of both sexes were classified into groups: (1) healthy adult controls, (2) healthy non-PPID geriatric horses, (3) PPID ID+ horses, and (4) PPID ID- horses. Whole blood proinflammatory cytokine gene expression and serum concent...
Klein C.Few, if any, biological processes are as diverse among domestic species as establishment of early pregnancy, in particular maternal recognition of pregnancy. Following fertilization and initial development in the mare oviduct, selective transport of the embryo through the uterotubal junction driven by embryo-derived PGE2 occurs. Upon arrival in the uterus, an acellular glycoprotein capsule is formed that covers the embryo, blastocyst, and conceptus (embryo and associated extraembryonic membranes) between the second and third weeks of pregnancy. Between Days 9 and 15/16 of pregnancy, the concep...
Price JS, Jackson B, Eastell R, Wilson AM, Russell RG, Lanyon LE, Goodship AE.In this study we tested the hypothesis that exercise induces an adaptive response in the developing skeleton which may be monitored in vivo by measuring biochemical markers of bone metabolism. The effects of exercise on two biochemical markers of bone formation were determined; the carboxy-terminal propeptide of type I procollagen (PICP), and the bone-specific isoenzyme of alkaline phosphatase (BAP), and one putative marker of resorption, the pyridinoline crosslinked telopeptide domain of type I collagen (ICTP). All three markers were measured for a year in 2-year-old thoroughbred horses exerc...
Gastal GDA, Aguiar FLN, Alves BG, Alves KA, de Tarso SGS, Ishak GM, Cavinder CA, Feugang JM, Gastal EL.Ovarian tissue cryopreservation allows the preservation of the female fertility potential for an undetermined period. The objectives of this study were to compare the efficiency of cryoprotective agents (CPAs; dimethyl sulfoxide, DMSO; ethylene glycol, EG; and propylene glycol, PROH) using slow-freezing and vitrification methods, and evaluate the viability of cryopreserved equine ovarian tissue after 7 days of culture. Fresh and cryopreserved ovarian fragments were evaluated for preantral follicle morphology, stromal cell density, EGFR, Ki-67, Bax, and Bcl-2 protein expression, and DNA fragmen...
Podico G, Canisso IF, Roady PJ, Austin SM, Carossino M, Balasuriya U, Ellerbrock RE, Lima FS, Ferreira-Dias G, Douglas RH.Pregnancy loss during the normal lifespan of endometrial cups (∼37-120-150 days of gestation) may affect a mare's ability to conceive again in the same breeding season, as equine chorionic gonadotropin (eCG) secretion by retained endometrial cups can lead to abnormal ovulations and follicular growth. While intrauterine kerosene infusion has anecdotally been proposed as a treatment for endometrial cup retention, there are no controlled studies evaluating kerosene's ability to enhance endometrial cup regression following abortion. The objectives of this study were to assess uterine response, s...
Meyer W, Schoennagel B, Kacza J, Busche R, Hornickel IN, Hewicker-Trautwein M, Schnapper A.We studied the esophageal epithelium for keratinization characteristics from samples of domesticated mammals of three nutrition groups (herbivores: horse, cattle, sheep; omnivores: pig, dog, rat; carnivores: cat) using histochemistry (keratins, disulfides), sulfur measurements, and cryo-SEM. Keratins were found in all esophageal layers of all species, except for the equine Stratum corneum. The positive reaction staining of Pan-keratin was remarkable, but decreased in intensity toward the outer layers, whereas in the pig and cat, staining was confined to the corneal layer. The herbivores reveal...
