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.
Kasashima Y, Takahashi T, Birch HL, Smith RK, Goodship AE.Tendons can be considered in two functional groups, those contributing to energetics of locomotion and those acting solely to position the limb. The energy-storing tendons in both human and equine athletes have a high frequency of injury with similar pathophysiology. In previous studies, high-intensity exercise appears to induce a disruption of the matrix rather than functional adaptation in adults. Here we explore the hypothesis that the introduction of controlled exercise during growth would result in an adaptive response without deleterious effects. Young horses were given a controlled exer...
Parillo F, Verini Supplizi A.The present work was undertaken to determine the glycoconjugates secreted by the epithelium of the equine ampulla ductus deferentis, using conventional (PAS, AB pH 2.5, AB pH 1.0) and lectin histochemical procedures in conjunction with enzymatic digestion and chemical treatment. The presence of abundant apical cytoplasmic blebs suggests that the equine ampulla secretes its products mainly in an apocrine manner. Glandular cells secrete neutral and acidic sialylated glycoconjugates as revealed by conventional histochemical procedures. Lectin histochemistry helped us to discover the following his...
Lefranc A-, Allen WR.The morphology and surface density of endometrial glands responsible for the nutrition of the placenta requires further study employing computer assisted morphometric analysis. Objective: To analyse changes in the morphology and surface density of endometrial glands situated adjacent to, and remote from, the conceptus during the first 30 days of gestation. Methods: Endometrial biopsies were recovered, under videoendoscopic control, from both nonpregnant and pregnant mares 12 days after ovulation, as well as from pregnant mares on Days 16, 20, 25 and 30 of gestation. One biopsy was taken at the...
Dunkel B, Rickards KJ, Page CP, Cunningham FM.Platelet activation occurs in human obstructive airway diseases and in laboratory animal models. However, there is limited evidence that platelets may be involved in equine recurrent airway obstruction (RAO) and other inflammatory diseases. This study investigated whether platelet activation also occurred in RAO. Objective: Platelet function is altered in ponies with active RAO. This alteration can be detected ex vivo by measuring platelet adhesion. Methods: An in vitro platelet adhesion assay measuring acid phosphatase (AcP) activity colorimetrically was adapted for use with equine platelets ...
Leise BS, Fugler LA, Stokes AM, Eades SC, Moore RM.To determine the magnitude and duration of effects of acepromazine administered intramuscularly (IM) on digital and systemic hemodynamic variables in clinically healthy horses. Methods: Experimental study. Methods: Healthy adult horses (n=12). Methods- An ultrasonic Doppler flow probe was surgically implanted around the medial palmar digital artery before the study. Catheters were inserted in the transverse facial artery, lateral palmar digital artery, and jugular vein. A treatment group (n=6) was administered 0.04 mg/kg body weight of acepromazine IM; control horses (n=6) were administered an...
Butcher MT, Hermanson JW, Ducharme NG, Mitchell LM, Soderholm LV, Bertram JE.Racing and training related lesions of the forelimb superficial digital flexor tendon are a common career ending injury to racehorses but aetiology and/or predisposing causes of the injury are not completely understood. Objective: Although the injury takes place within the tendon, the lesion must be considered within the context of the function of the complete suspensory system of the distal limb, including the associated muscles. Methods: Both muscle and tendon function were investigated in vivo using implanted strain gauges in 3 Thoroughbred horses walking, trotting and cantering on a motori...
Wilson ME.Pathologic conditions of the urinary tract may produce specific clinical signs, but they are more than likely to be nonspecific clinical signs, which often occur with chronic renal disease in addition to countless other diseases. Further, clinical signs that may seem to be directly related to the urinary tract may be the result of other systemic diseases. Thus, before embarking on diagnostics, it is important to obtain a thorough history and physical examination.
Arroyo LG, Stämpfli HR.Renal tubular disorders have been sporadically reported in horses. Only three types of tubular defects have been recognized: (1) nephrogenic diabetes insipidus, attributable to unresponsiveness of the renal tubules to antidiuretic hormone; (2) distal renal tubular acidosis (RTA; type I); and (3) proximal RTA (type II). The following review focuses on RTA and nephrogenic diabetes insipidus.
Dunkel B, Rickards KJ, Page CP, Cunningham FM.To determine the phosphodiesterase (PDE) isoenzymes in equine platelets and evaluate their influence on platelet adhesion. Methods: Platelets obtained from healthy New Forest Pony geldings that ranged from 12 to 20 years of age (mean +/- SEM, 17.3 +/- 1.1 years). Methods: PDE isoenzyme activity in equine platelets was determined by use of a 2-step radioactive assay. Functional importance of PDE isoenzymes was established by use of selective inhibitors in a colorimetric adhesion assay. Results: PDE1, PDE2, PDE3, and PDE5 and small amounts of PDE4 were found in equine platelets. Inhibition of PD...
Toribio RE.Knowledge of urinary tract anatomy and the numerous functions of the kidney in regulating fluids, electrolytes, acid-base balance, and waste products improves the ability of the clinician to diagnose, treat, and make appropriate recommendations for the management of the horse with renal disease. Several conditions can directly or indirectly affect renal function on a temporary or permanent basis. Endogenous and exogenous compounds (eg, drugs, toxins, hemoglobin) alone or in combination with inappropriate renal blood flow can promote or exacerbate renal disease.
Schumacher J.Hematuria and pigmenturia of horses are discussed in this article. Equine urine is normally straw colored. Discolored urine can be caused by contamination with red blood cells, hemoglobin, myoglobin, oxidizing agents normally found in urine, and plant-derived pigments.
Giguère S, Sanchez LC, Shih A, Szabo NJ, Womble AY, Robertson SA.To determine and compare the effects of caffeine and doxapram on cardiorespiratory variables in foals during isoflurane-induced respiratory acidosis. Methods: 6 clinically normal foals (1 to 3 days old). Methods: At intervals of > or = 24 hours, foals received each of 3 IV treatments while in a steady state of hypercapnia induced by isoflurane anesthesia (mean +/- SD, 1.4 +/- 0.3% endtidal isoflurane concentration). After assessment of baseline cardiorespiratory variables, a low dose of the treatment was administered and variables were reassessed; a high dose was then administered, and vari...
Leeb T.The growing knowledge on physiology, cell biology and biochemistry of the reproductive organs has provided many insights into molecular mechanisms that are required for successful reproduction. Research directed at the investigation of reproduction physiology in domestic animals was hampered in the past by a lack of species-specific genomic information. The genome sequences of dog, cattle and horse have become publicly available in 2005, 2006 and 2007 respectively. Although the gene content of mammalian genomes is generally very similar, genes involved in reproduction tend to be less conserved...
Brindley MA, Maury W.Entry of wild-type lentivirus equine infectious anemia virus (EIAV) into cells requires a low-pH step. This low-pH constraint implicates endocytosis in EIAV entry. To identify the endocytic pathway involved in EIAV entry, we examined the entry requirements for EIAV into two different cells: equine dermal (ED) cells and primary equine endothelial cells. We investigated the entry mechanism of several strains of EIAV and found that both macrophage-tropic and tissue culture-adapted strains utilize clathrin-coated pits for entry. In contrast, a superinfecting strain of EIAV, EIAV(vMA-1c), utilizes ...
Thorpe CT, Marlin DJ, Franklin SH, Colborne GR.Changes in shape of the equine thorax during locomotion are not well defined, although it has been shown recently that the transverse hemi-diameter changes its dimension by up to 80mm on the side of the trailing forelimb during gallop, despite minimal change in thoracic circumference. The aim of this project was to analyse transverse and dorso-ventral changes in shape of the thorax simultaneously, and to determine if leading limb, treadmill slope and speed have an effect on these shape changes. Reflective markers were placed on the horse's hemi-thorax and movement of the markers was recorded u...
Morita H, Shiratori C, Murakami M, Takami H, Kato Y, Endo A, Nakajima F, Takagi M, Akita H, Okada S, Masaoka T.Two strains, KBL13(T) and GBL13, were isolated as one of intestinal lactobacilli from the faecal specimens from different thoroughbreds of the same farm where they were born in Hokkaido, Japan. They were Gram-positive, facultatively anaerobic, catalase-negative, non-spore-forming and non-motile rods. KBL13(T) and GBL13 homofermentatively metabolize glucose, and produce lactate as the sole final product from glucose. The 16S rRNA gene sequence, DNA-DNA hybridization, DNA G+C content and biochemical characterization indicated that these two strains, KBL13(T) and GBL13, belong to the same species...
Piccione G, Bertolucci C, Grasso F, Guidice E.The effect of storage temperature and time on blood gas and acid-base values has been investigated intensively in cattle and dogs; however, data are lacking in other species. Objective: The aim of our study was to evaluate changes in gas composition and acid-base values in venous blood stored at different temperatures and for different times in 4 domestic species in Italy. Methods: Blood samples from Comisana sheep (n = 10), Maltese goats (n = 10), Ragusana donkeys (n = 10), and Thoroughbred horses (n = 10) were analyzed after storage at 23 degrees C (room temperature) for 15 minutes (group I)...
Hülsemann F, Flenker U, Machnik M, Schänzer W.Sodium bicarbonate administration to horses prior to competition in order to enhance the buffer capacity of the organism is considered as a doping offence. The analysis of the isotopic composition of urinary bicarbonate/CO(2) (TCO(2)) may help to identify an exogenous bicarbonate source, as technical sodium bicarbonate exhibits elevated delta(13)C values compared with urinary total carbon. The isolation of TCO(2) from 60 equine urine samples as BaCO(3) followed by an isotopic analysis shows a significant variability of delta(13)C for TCO(2) of more than 10 per thousand. The delta(13)C of total...
Price S, Aurich J, Davies-Morel M, Aurich C.This study was undertaken to investigate the effects of storage of stallion semen in a defined milk protein extender at 5 and 15 degrees C under either anaerobic or aerobic conditions, with or without addition of the antibiotic gentamicin. Semen samples were collected from eight fertile stallions and stored for 96 h (day 0-4) and assessed daily for motility, velocity and membrane integrity (viability) using a CASA system. Samples for bacteriology assessment were taken on day 2 of storage. No significant (p > 0.05) differences in motility, velocity or viability were observed between treatmen...
Loomis PR, Graham JK.One of the challenges for those attempting to cryopreserve stallion spermatozoa is dealing with the stallion to stallion variability in the cryosurvival of their semen. In the dairy industry, each bull stud, essentially utilizes a single cryopreservation technique, and bulls that produce sperm that do not cryopreserve well using that technique are replaced by other bulls. However, replacing stallions is unlikely to prove acceptable to the equine industry, where specific genotypes are desired. Instead, to increase the number of stallions that can be effectively utilized for cryopreserved semen ...
Rambags BP, van Tol HT, van den Eng MM, Colenbrander B, Stout TA.Progesterone and oestrogen play essential roles in the maintenance of pregnancy in eutherian mammals and are thought to exert their effects on the developing conceptus indirectly, via the endometrium. In some species, early embryos have themselves been shown to express steroid receptors, thereby suggesting that reproductive steroids may also influence embryonic development directly. The aim of this study was to determine whether early intrauterine equine conceptuses express either the classical intracellular progesterone (PR) and oestrogen receptors (ERalpha and ERbeta) or the more recently ch...
Janicek JC, Carson WL, Wilson DA.The purpose of this investigation was to design and verify the capabilities of an in vitro loading-measurement system that mimics in vivo unconstrained three dimensional (3D) relative motion between long bone ends, applies uniform load components over the entire length of a test specimen, and measures 3D relative motion between test segment ends to directly determine test segment construct stiffness free of errors due to potting-fixture-test machine finite stiffness.Intact equine cadaveric radius bones, which were subsequently osteotomized/ostectomized and instrumented with bone plates were su...
Gregg AJ, Schenkel AR.Platelet endothelial cell adhesion molecule (PECAM, CD31) and vascular cell adhesion molecule-1 (VCAM-1, CD106) are essential for leukocyte emigration and diapedesis. PECAM is an essential histologic marker of endothelial cells; VCAM-1 is a prototype marker for endothelial cell activation. In this study, equine PECAM and VCAM mRNA were cloned and sequenced. Both genes are highly conserved amongst several species. This study also revealed conserved structural and regulatory motifs, emphasizing the importance of these genes' physiological roles in immunological responses.
Ginther OJ, Gastal EL, Gastal MO, Beg MA.The effect of an injection of a supraphysiologic dose of rhIGF1 into the second-largest ovarian follicle (F2) at the expected beginning of deviation (F1, > or =20 mm; Day 0) on development of dominance by F2 was studied in mares (n=16; controls, n=8). F1 became dominant (> or =28 mm) in 8 of 8 and 15 of 16 follicles in the controls and treated groups, respectively. The incidence of dominance (P<0.001) and ovulation (P or =20mm after the expected beginning of deviation resulted in dominance by 8 of 12 follicles treated with rhIGF1 on Days 1-3 (n=8 mares). Results demonstrated that the ...
Diaz OS, Smith G, Reef VB.The purpose of this study was to describe the normal ultrasonographic appearance of the caudal portion of the equine ureters, pelvic urethra, and urinary bladder and to assess ureteral contractility. Fifteen horses with no evidence of urinary tract disease (five females, five intact males and five geldings) were studied. The lower urinary tract was evaluated ultrasonographically using a transrectal approach. The normal ultrasonographic appearance and anatomic location of structures of the lower urinary tract were evaluated and anatomic relationships described. Both ureters were identified dors...
Gorgas D, Kircher P, Doherr MG, Ueltschi G, Lang J.Radiography is part of evaluating horses with poor performance and pelvic limb lameness; however, the radiographic appearance of the sacroiliac region is poorly described. The goal of the present study was to describe the use of a simple technique to obtain radiographs of the sacroiliac region in the anesthetized horse and to describe the radiographic appearance of this region. Seventy-nine horses underwent radiography of the pelvis under general anesthesia in dorsal recumbency. During a 5s exposure time the horse was actively ventilated to blur the abdominal viscera, which allowed assessment ...
Bigley RF, Gibeling JC, Stover SM, Hazelwood SJ, Fyhrie DP, Martin RB.Volume effects are a fundamental determinant of structural failure. A material exhibits a volume effect if its failure properties are dependent on the specimen volume. Many brittle ceramics exhibit volume effects due to loading a structure in the presence of "critical" flaws. The number of flaws, their locations, and the effect of stress field within the stressed volume play a role in determining the structure's failure properties. Since real materials are imperfect, structures composed of large volumes of material have higher probabilities of containing a flaw than do small volumes. Consequen...
Kozelek P, Holcik J, Sedlinska M.The paper describes experiments and their results that offered an insight to relationship between RR and QT intervals in equine ECG signals recorded under various conditions. In contrast to human heart in a great number of cases the QT intervals prolonged with a heart rate acceleration. Peak-to-peak differences between maximum and minimum RR intervals during the excitation response in non-standard responses were twice as smaller as in standard responses and the lengths of QT intervals were significantly longer in the non-standard records. This fact means that the electrical processes in equine...
Pearson W, Orth MW, Lindinger MI.Herbs are an increasingly popular treatment option for horses with cartilage inflammation, despite a relative paucity of research demonstrating efficacy. The research objective was to evaluate the differential anti-inflammatory and chondroprotective efficacy of a simulated digest of indomethacin and a commercially available herbal product in a cartilage model of osteoarthritis. Cartilage explant was integrated with simulated digestion of indomethacin and the herbal product in order to account, at least in part, for the actions of major digestive enzymes and pH. The resulting digests were ultra...
Herholz C, Tschudi P, Gerber H, Moens Y, Straub R.A new computerised ultrasound-based spirometry system according to Buess et al. (1995) modified by a double flow measurement facility was used to study pulmonary function in healthy horses and horses affected with subclinical and manifest chronic bronchiolitis (CB). The horses were first evaluated at rest without any medication. On another occasion all horses were tested following i.v. administration of xylazine (0.4 mg/kg) and following i.v. administration of lobeline hydrochloride (l.hy.; 0.2 mg/kg) to evaluate the effect of xylazine and l.hy. on different spirometric variables. Ultrasound-b...
Hussein H, Boyaka P, Dulin J, Russell D, Smanik L, Azab M, Bertone AL.Selective inhibition of Cathepsin K (CatK) has a promising therapeutic potential for diseases associated with bone loss and osseous inflammation, such as osteoarthritis, periodontitis, and osteoporosis. In horses, stress-related bone injuries are common and accompanied by bone pain and inflammation resulting in excessive bone resorption and periostitis. VEL-0230 is a highly selective inhibitor of CatK that significantly decreased bone resorption and increased bone formation biomarkers. The goal of this study was to demonstrate the presence of CatK in equine bone and a simultaneous influence on...
Morrell JM, Stuhtmann G, Meurling S, Lundgren A, Winblad C, Macias Garcia B, Johannisson A.Many attempts have been made to identify laboratory tests that are predictive of sperm fertility, both to improve the quality of stallion semen doses for artificial insemination (AI) and to identify potential breeding sires if no fertility data are available. Sperm quality at the stud is mostly evaluated by assessing subjective motility, although this parameter can be poorly indicative of fertility. Sperm morphology and chromatin integrity in Swedish stallions are correlated to pregnancy rate after AI. Because single layer centrifugation (SLC) selects for spermatozoa with normal morphology and...
Dietrich J, Handschuh S, Steidl R, Böhler A, Forstenpointner G, Egerbacher M, Peham C, Schöpper H.As the longissimus dorsi muscle is the largest muscle in the equine back, it has great influence on the stability of the spine and facilitates proper locomotion. The longissimus muscle provides support to the saddle and rider and thereby influences performance in the horse. Muscular dysfunction has been associated with back disorders and decline of performance. In general, muscle function is determined by its specific intramuscular architecture. However, only limited three-dimensional metrical data are available for the inner organisation of the equine longissimus dorsi muscle. Therefore, we a...
The Journal of parasitologyApril 25, 2001
Volume 87, Issue 2 442-445 doi: 10.1645/0022-3395(2001)087[0442:ETPIGN]2.0.CO;2
Medica DL, Sukhdeo MV.Microparasite virulence (the potential to cause harm in the host) is thought to be regulated by a direct trade-off with pathogen transmission potential, but it is unclear whether similar trade-offs occur in macroparasites (helminths). In this analysis, the transmission potentials of 5 nematode species (order Strongylida), known to differ in their virulence, were estimated using an index based on egg production and larval survivability. Virulence estimates were based on the minimum number of worms that cause host death. In nematode species where mature adults cause pathology (trichonematidic de...
Peng Z, Shen D, Zhang D, Li X, Wang L, Zhai Q, Hou Z, Li H.The equine Parascaris spp. is large, parasitic nematodes, and predominantly focuses on the intestine of foals and young weanlings. There are two roundworms, Parascaris equorum and Parascaris univalens, recognized among equine hosts. In this study, all fifty-nine Parascaris worms were harvested from three different equine hosts (twenty specimens from Equus zebra, twenty specimens from E. caballus, and nineteen specimens from E. asinus). The ribosomal gene (ITS) and mitochondrial genes (cox1 and nadh1) were amplified to identify and genetically characterize these worms. Analysis of ITS sequences...
The measurement of cell proliferation and cell viability using 5'bromo-2'deoxy-uridine (BrdU) labelling has been described in several cell types and species. The aim of this study was to adapt this technique to equine embryos and to compare the index of DNA replication (S-phase) between equine and caprine embryos. Seventeen equine embryos were recovered at day 6.5 post-ovulation and 20 caprine embryos were recovered at day 7 after the onset of estrus. Equine embryos were incubated during 1h at 39 degrees C in PBS containing 1mM of BrdU. Embryos were then treated in 0.05% trypsin during 15 min ...
Honnens A, Weisser S, Welter H, Einspanier R, Bollwein H.The objective of this study was to investigate the relationships between uterine perfusion and estrogen, progesterone and the uterine nitric oxide synthase (NOS) system in five trotter mares during the estrous cycle. Color Doppler sonography for measurement of uterine blood flow and collection of blood for determination of plasma estrogen and progesterone concentrations were performed on days 0 (= ovulation), 1, 5, 11 and 15 and daily during estrus (days -1 to -4) of one estrous cycle; endometrial biopsy collection for mRNA expression analysis of NOS and estrogen receptors was performed on day...
Christmann U, Hite RD, Witonsky SG, Elvinger F, Werre SR, Thatcher CD, Tan RH, Buechner-Maxwell VA.Surfactant alterations are described in horses after exercise, anesthesia, and prolonged transport, in horses with recurrent airway obstruction, and in neonatal foals. The effect of horse age or bronchoalveolar lavage fluid (BALF) sample characteristics on surfactant is unknown. Objective: To evaluate surfactant phospholipid composition and function in healthy horses, and to investigate the influence of age and BALF sample characteristics on surfactant. Methods: Seventeen healthy horses 6-25 years of age maintained on pasture year-round. Methods: BALF was collected by standard procedures and w...
Greene CE, Tsang VC, Prestwood AK, Meriwether EA.Optimal reaction conditions for the activated partial thromboplastin time (APTT), 1-stage prothrombin time (PT), and Russell's viper venom time were studied for pooled plasmas of horses, cattle, sheep, goats, swine, dogs, cats, and persons. Changes in CaCl2 and NaCl concentrations had significant effects on the APTT and PT reactions. The APTT was more sensitive than the PT to changes in CaCl2 concentration. The CaCl2 concentration recommended by the manufacturer for the APTT was suboptimal for some of plasmas of domesticated animals in ths study. Infusorial earth (Celite, activator) concentrat...
Schmitz A, Thormann W, Moessner L, Theurillat R, Helmja K, Mevissen M.Ketamine, an injectable anesthetic and analgesic consisting of a racemic mixture of S-and R-ketamine, is routinely used in veterinary and human medicine. Nevertheless, metabolism and pharmacokinetics of ketamine have not been characterized sufficiently in most animal species. An enantioselective CE assay for ketamine and its metabolites in microsomal preparations is described. Racemic ketamine was incubated with pooled microsomes from humans, horses and dogs over a 3 h time interval with frequent sample collection. CE data revealed that ketamine is metabolized enantioselectively to norketamine...
Li Y, Yao J, Chang M, Nikolic D, Yu L, Yager JD, Mesecar AD, van Breemen RB, Bolton JL.Catechol-O-methyltransferase (COMT) plays an important role in the inactivation of biologically active and toxic catechols. It has been shown that COMT is genetically polymorphic with a wild-type and variant form where a valine has been substituted with a methionine. Several, but not all, epidemiological studies have shown that women, homozygous with the variant form, have an increased risk of developing breast cancer. Previously, we showed that 4-hydroxyequilenin (4-OHEN), a cytotoxic/genotoxic equine catechol estrogen metabolite, is both a substrate of COMT and an irreversible inhibitor of t...
Gottlieb M, Essén-Gustavsson B, Lindholm A, Persson SG.Circulatory and muscle metabolic responses were studied in 10 horses which all performed incremental draught work at a low trotting speed on a treadmill (D-test) and also exercise with gradually increasing velocities (S-test). Exercise was continued until the horses could no longer maintain the weights above the floor or maintain speed trotting without changing gait to a gallop. Muscle biopsies were taken from the gluteus and the semitendinosus muscles before, and immediately after, exercise. The heart rate (HR) increased linearly with both increasing draught resistance and velocity and reache...
Manao G, Camici G, Stefani M, Berti A, Cappugi G, Liguri G, Nassi P, Ramponi G.Acylphosphatase was purified from horse muscle by a new procedure involving an affinity chromatography step and subsequent ion-exchange chromatography. This procedure was considerably milder than the preceding one, gave an overall yield of about 60% of activity and permitted isolation of three molecular forms with acylphosphatase activity. All these enzymatic forms are tightly bound to Sepharose 4B-linked anti-horse muscle acylphosphatase antibodies. Two of these forms (Ho1 and Ho3) are present in larger amounts: Ho1 corresponds to the enzyme purified according to the older procedure; this enz...
Lindner A, Signorini R, Brero L, Arn E, Mancini R, Enrique A.There is limited published work on the effect of training using intensive and short intervals of exercise to condition horses for racing. Objective: To examine the effect of conditioning horses 1, 2 or 3 x a week using 2 short fast exercise intervals on blood lactate (LA), plasma ammonia (NH3) and urea (urea) as well as creatine kinase (CK) activity. Methods: Thoroughbreds (age 4-5 years) were conditioned at near maximal speed (12-14 m/sec) over 100 m, on 2 occasions separated by a 10 min period at walk, on dirt track (conditioning exercise; CE) during a 6 week conditioning period (CP). The CE...
Arrighi S, Romanello MG, Domeneghini C.The epithelium that lines the ductuli efferentes in the horse, donkey and mule has been examined by electron microscopy. The epithelium consists of columnar ciliated and non-ciliated cells. Lymphocytes and macrophages are also present, together with cells that are rich in lipofuscin. These 'lipofuscin-rich' cells are a peculiar feature of the excurrent ducts of Equidae and are characterized by a large number of highly heterogeneous residual bodies. The general morphology of the epithelium and, in particular, of the non-ciliated cells implies that the epithelium is involved in the absorption an...
McD￮ LA, Anderson GI, Wright GM, Ryan DA.Bone cell cultures were evaluated to determine if osteogenic cell populations at different skeletal sites in the horse are heterogeneous. Osteogenic cells were isolated from cortical and cancellous bone in vitro by an explant culture method. Subcultured cells were induced to differentiate into bone-forming osteoblasts. The osteoblast phenotype was confirmed by immunohistochemical testing for osteocalcin and substantiated by positive staining of cells for alkaline phosphatase and the matrix materials collagen and glycosaminoglycans. Bone nodules were stained by the von Kossa method and counted....
Johnson PJ, Goetz TE, Foreman JH, Vogel RS, Hoffmann WE, Baker GJ.The effects of whole-body potassium depletion induced by food deprivation on plasma, erythrocyte, and middle gluteal muscle K concentrations was quantified in 16 healthy, adult horses before, during, and at the end of a 7-day period of food deprivation during which water and sodium chloride were available ad libitum. Potassium concentrations were determined by atomic absorption spectroscopy. Plasma K concentration remained constant (3.49 +/- 0.09 mM K/L of plasma; mean +/- SEM) throughout the study. Erythrocyte potassium concentration decreased from 93.10 +/- 1.94 mM K/L of erythrocytes on day...
Lanata A, Guidi A, Valenza G, Baragli P, Scilingo EP.This study focuses on the analysis of human-horse dynamic interaction using cardiovascular information exclusively. Specifically, the Information Theoretic Learning (ITL) approach has been applied to a Human-Horse Interaction paradigm, therefore accounting for the nonlinear information of the heart-heart interplay between humans and horses. Heartbeat dynamics was gathered from humans and horses during three experimental conditions: absence of interaction, visual-olfactory interaction, and brooming. Cross Information Potential, Cross Correntropy, and Correntropy Coefficient were computed to qua...
Binetti A, Mosing M, Sacks M, Duchateau L, Gasthuys F, Schauvliege S.To describe the cardiorespiratory effects of a change in table position in anaesthetized horses. Methods: Prospective, crossover, randomized, experimental study. Methods: Six adult horses (mean body weight 621 ± 59 kg, aged 13 ± 4 years). Methods: The horses were anaesthetized twice in dorsal recumbency. They were either placed in the Trendelenburg position (head down; HD) followed by reverse Trendelenburg position (head up; HU) or in reverse order. Every position was maintained for 90 minutes. The order of positions was randomly assigned at initial anaesthesia. Extensive cardiorespiratory m...
Meyers SA, Overstreet JW, Liu IK, Drobnis EZ.Mammalian sperm that have completed capacitation are capable of undergoing the acrosome reaction in response to a number of biological and chemical stimuli. In the present report, we have investigated the ability of progesterone to stimulate acrosome reactions of stallion sperm capacitated in vitro. Motile sperm were selected by a two-layer Percoll gradient centrifugation and were incubated in TALP medium modified by the 1:1 (v/v) addition of TEST-yolk medium for 5 hours at 39 degrees C, under 5% CO2 in humidified air. Sperm incubated in vitro in TALP-TEST medium had a higher percentage of acr...
Sojka JE, Adams SB, Lamar CH, Eller LL.Effect of butorphanol, pentazocine, meperidine, and metoclopramide on jejunal and pelvic flexure myoelectric and mechanical activity in 4 female ponies was investigated. The agent to be tested or saline solution was administered IV at the start of a 6-hour recording trial. In the jejunum, duration between activity fronts of regular spiking activity, defined as the length of the migrating myoelectric complex (MMC), was measured. The average duration of the MMC during control trials was 150 +/- 46 minutes. The average duration of the MMC after meperidine, butorphanol, pentazocine, and metoclopra...
Gautier C, Scarlet D, Ertl R, Walter I, Wulf M, Nagel C, Aurich J, Aurich C.The aim of the present study was to characterise key enzymes involved in polyunsaturated fatty acid (PUFA) synthesis in the testis and epididymis collected from 2-year-old healthy warmblood stallions (n=10). The mRNA expression of fatty acid synthase, the Δ9-, Δ6-, Δ5- and Δ4-desaturases and elongases 6, 5 and 2 (encoded by the fatty acid synthase (FASN), the stearoyl-CoA desaturase (SCD), the fatty acid desaturase 2 (FADS2), the fatty acid desaturase 1 (FADS1), the delta 4-desaturase, sphingolipid 1 (DEGS1), ELOVL fatty acid elongase 6(ELOVL6), ELOVL fatty acid elongase 5 (ELOVL5), ELOVL ...
Klein C, Bruce P, Hammermueller J, Hayes T, Lillie B, Betteridge K.The current study used RNA sequencing to determine transcriptional profiles of equine endometrium collected 14, 22, and 28 days after ovulation from pregnant mares. In addition, the transcriptomes of endometrial samples obtained 20 days after ovulation from pregnant mares, and from non-pregnant mares which displayed and failed to display extended luteal function following the administration of oxytocin, were determined and compared in order to delineate genes whose expressions depend on the presence of the conceptus as opposed to elevated progesterone alone. A mere fifty-five transcripts were ...
Carlson GP, Rumbaugh GE, Harrold D.Eight normal horses were held without access to food or water for 72 hours during a period of high environmental temperatures. During this period, the horses had an average weight loss of 51.6 kg (10.7% of body weight). Highly significant (P less than 0.001) decreases in extracellular fluid volume (18.6 L) and plasma volume (5 L) were observed during this period as compared with base-line values. Plasma protein, sodium, chloride, and osmolality progressively increased in response to the dehydration, whereas packed cell volume, plasma potassium, calcium, magnesium, and phosphate were not signif...
van den Boom R, Brama PA, Kiers GH, de Groot J, van Weeren PR.To assess the effects of age and joint disease on hydroxyproline and glycosaminoglycan (GAG) concentrations in synovial fluid from the metacarpophalangeal joint of horses and evaluate the association of those concentrations with severity of osteoarthritis and general matrix metalloproteinase (MMP) activity. Methods: Synovial fluid was collected from the metacarpophalangeal joints of foals at birth (n = 10), 5-month-old foals (10), 11-month-old foals (5), and adult horses (73). Methods: Hydroxyproline and GAG concentrations were determined in synovial fluid samples. The severity of osteoarthrit...
Lancaster LS, Bowker RM.Veterinary acupuncture charts were developed based on the concept of transpositional points whereby human acupuncture maps were adapted to animal anatomy. Transpositional acupuncture points have traditionally been placed in specific locations around the horse's coronet and distal limb believed to be the closest approximation to the human distal limb points. Because the horse has a single digit and lacks several structures analogous to the human hand and foot, precisely transposing all of the human digital points is not anatomically possible. To date there is no published research on the effect...
McConaghy FF, Hodgson DR, Hales JR, Rose RJ.Cardiac output (Q) and tissue blood flows (BF) were measured in four ponies at rest, after 30 min of moderate exercise (ME) (approximately 30% VO2max) and following moderately intense exercise (M-IE) (approximately 65%) until fatigue, in a mildly hot (MH) environment (dry bulb temperature = 41 degrees C, wet bulb temperature = 27.5 degrees C). Exercise at both intensities resulted in increases in Q (15.6 +/- 1.7 [rest] vs. 35.8 +/- 2.6 [ME] vs. 48.6 +/- 3.9 [M-IE] l/min) and VO2 (4.7 +/- 0.9 vs. 24.5 +/- 1.2 vs. 55.8 +/- 5.8 ml/kg/min). When compared to ME, M-IE resulted in decreases in BF to ...
Seino KK, Foreman JH, Greene SA, Goetz TE, Benson GJ.Capsaicin is a local substance P depleter with dramatic analgesic effects. We tested the hypothesis that the topical application of capsaicin ointment over the palmar digital nerves would attenuate the clinical effects of a reversible model of equine foot lameness. Seven healthy adult horses shod unilaterally with adjustable heart bar shoes were studied in a crossover design for 2 weeks. Grade 5.0/5.0 lameness (nonweight bearing) was induced by tightening the adjustable heart bar shoe. One hour later, capsaicin ointment was applied over the medial and lateral palmar digital nerves 3 cm proxima...
Ortgies F, Klewitz J, Görgens A, Martinsson G, Sieme H.Reasons for low in vitro fertilisation rates in the horse include the difficulties in inducing capacitation and/or hyperactivation of stallion spermatozoa. The aim of this study was to analyse the effect of noncapacitating and capacitating modified Whitten's (MW) and modified Tyrode's medium (MT) and treatment with procaine (5 mmol), pentoxifylline (3.5 mmol) and trolox (120 mmol) on motility (CASA), capacitation, acrosomal status, viability and mitochondrial membrane potential of stallion spermatozoa (n = 4). While there was no influence of MW and MT on sperm motility, a significant increase ...
