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.
Ho EN, Yiu KC, Tang FP, Dehennin L, Plou P, Bonnaire Y, Wan TS.Boldenone (1,2-dehydrotestosterone) is a common veterinary anabolic agent. Its structure is very similar to testosterone. Testosterone is endogenous in the horse, whereas there has been no report concerning the detection of endogenous boldenone. This paper reports the direct observation of sulphate conjugate of boldenone in equine urine from entires. The detection procedures involved solid-phase extraction, immunoaffinity column (IAC) purification, and then LC-MS-MS analysis on a Q-ToF instrument. The identification of boldenone sulphate has provided direct evidence for the endogenous nature o...
Fintl C, Pearson GT, Ricketts SW, Mayhew IG, Hudson NP.This study set out to determine the pattern of development and distribution of the interstitial cells of Cajal (ICC) in the intestinal tract of the equine fetus and neonate. Intestinal tissue samples from 12 naturally aborted equine fetuses and three euthanized neonates were collected and fixed in formalin prior to applying standard immunohistochemical labelling techniques targeting the c-Kit protein of the ICC. At 6 months of gestation, a network of ICC was present in the myenteric plexus region of both the small and the large intestine. ICC were also present within the circular muscle layer....
Schumacher J, Livesey L, DeGraves FJ, Schumacher J, Schramme MC, Hathcock J, Taintor J, Gomez J.Anaesthesia of the palmar digital nerves is claimed to attenuate lameness in some horses that are lame because of pain in the proximal interphalangeal (PIP) joint. Objective: To determine the response of horses with pain in the PIP joint to anaesthesia of the palmar digital nerves. Methods: Horses were video recorded trotting before and after induction of pain in the PIP joint and 10 mins after anaesthesia of the palmar digital nerves. The palmar digital nerves were anaesthetised 3 times at different sites, and the video recorded gaits were scored subjectively. Results: The median lameness sco...
Métayer N, Lhôte M, Bahr A, Cohen ND, Kim I, Roussel AJ, Julliand V.Feeding practices have been associated with colic in horses. If meal size and composition have an effect on gastric emptying, this could be one of the mechanisms by which feeding practices are related to the occurrence of colic. Objective: To evaluate the effect of meal size and starch content on solid phase gastric emptying. Methods: Solid phase gastric emptying of 3 different radiolabelled meals, small low-starch (SmLS), small high-starch (SmHS) and large high-starch (LgHS) meals, was measured in 5 horses by scintigraphy using 99mTc-disofenin. Data were compared among meals using nonlinear m...
Driver AJ, Barr FJ, Fuller CJ, Barr AR.Tearing of the medial palmar intercarpal ligament (MPICL) has been recognised as a cause of lameness in the Thoroughbred, but diagnosis is difficult due to the nonspecific clinical signs, and can be achieved only by performing arthroscopy on the mid carpal joint (MCJ). It would be beneficial to be able to image the MPICL using ultrasonography to determine whether pathology is present in the ligament in order to aid diagnosis and prognosis. Objective: To determine whether the MPICL could be imaged using ultrasound from the dorsal aspect of the MCJ, and to describe the technique and normal ultra...
Puppione DL, Fischer WH, Park M, Whitelegge JP, Schumaker VN, Golfeiz S, MacDonald MH.Apolipoprotein A-II, the second major apolipoprotein of human HDL, also has been observed in a variety of mammals; however, it is either present in trace amounts or absent in other mammals. In humans and chimpanzee, and probably in other great apes, apoA-II with a cysteine at residue 6 is able to form a homodimer. In other primates as well as other mammals, apoA-II, lacking a cysteine residue, is monomeric. However, horse HDL has been reported to contain dimeric apoA-II that following reduction forms monomers. In this report, we extend these observations by reporting on the first complete sequ...
Piccione G, Assenza A, Grasso F, Caola G.BACKGROUND: Many physiological processes of mammalian species exhibit daily rhythmicity. An intrinsic relationship exists between fat soluble vitamins (A, D, E and K) and several body functions. Few investigations on the rhythmic pattern of vitamins in domestic animals have been carried out. The present study evaluated the circadian rhythmicity of fat soluble vitamins in the horse. METHODS: Blood samples from 5 Thoroughbred mares were collected at four-hour intervals over a 48-hour period (starting at 8:00 hours on day 1 and finishing at 4:00 on day 2) via an intravenous cannula inserted into ...
Weiss S, Janett F, Burger D, Hässig M, Thun R.The aim of the present study was to investigate the influence of various centrifugation methods on sperm loss and quality of frozen-thawed semen. From at a total of 8 Warmblood stallions of the National Stud Farm in Avenches, 3 ejaculates each were collected and seminal plasma was removed using 3 different centrifugation regimes. In method I (reference method) centrifugation occurred by a speed of 600 x g during 10 minutes. In method II 1000 x g was used during 2 minutes while in method III centrifugation was performed by 2000 x g during 2 minutes. After centrifugation 90%, of the supernatant ...
Arrighi S, Cremonesi F, Bosi G, Domeneghini C.Specimens of testis, excurrent duct including the male accessory glands and urethra, were studied in boars, bulls, horses and donkeys, in order to localize endocrine/paracrine cells. Silver impregnation methods were used to test the argentaffinity and/or argyrophilia of cells. Immunoreactivities to chromogranin A, 5-hydroxytryptamine, somatostatin, [met]- and [leu]- enkephalins, gastrin-releasing peptide, calcitonin gene-related peptide, neuropeptide Y, substance P, vasoactive intestinal peptide, beta-endorphin antisera were tested by a streptavidin-biotin method. In the testis, epididymis, du...
Ribeiro AA, Davis C, Gabella G.The superior (cranial) cervical ganglion was investigated by light microscopy in adult rats, capybaras (Hydrochaeris hydrochaeris) and horses. The ganglia were vascularly perfused, embedded in resin and cut into semi-thin sections. An unbiased stereological procedure (disector method) was used to estimate ganglion neuron size, total number of ganglion neurons, neuronal density. The volume of the ganglion was 0.5 mm3 in rats, 226 mm3 in capybaras and 412 mm3 in horses. The total number of neurons per ganglion was 18,800, 1,520,000 and 3,390,000 and the number of neurons per cubic millimetre was...
Briant C, Toutain PL, Ottogalli M, Magallon T, Guillaume D.The appropriate dosage regimen for equine FSH (eFSH) (dose, dosing interval) administration in a superovulation treatment in pony mares was determined by a kinetic approach using production rates and kinetic parameters of elimination of the hormone. Two dosage regimens were then tested in superovulation protocols. The eFSH production rates were determined by sampling four ovariectomized pony mares every 10 min for 8 h during the breeding season. Kinetic parameters were determined by administering four dose levels of a preparation of eFSH (4.4, 8.8, 17.6 and 35.2 micro g/kg) by the i.v. route t...
Stradaioli G, Sylla L, Zelli R, Chiodi P, Monaci M.The effect of orally administered l-carnitine on the quality of semen obtained from stallions with different semen qualities was investigated. Four stallions with proven fertility (high motility group, HM) and with normal seminal characteristics (>50% progressive motility and > 80 x 10(6) spermatozoa/ml), and four questionable breeders (low motility group, LM) with <50% of sperm progressive motility and < 80 x 10(6) spermatozoa/ml, received p.o. 20 g of l-carnitine for 60 days. Blood and semen samples were collected before treatment (T0) and after 30 (T1) and 60 days (T2). Semen ev...
Pedersen HG, Watson ED, Telfer EE.The effects of ovary holding time and temperature on granulosa cell apoptosis, oocyte chromatin configuration and cumulus morphology were investigated through a series of experiments. Three experiments were performed to determine the effect of ovary holding time and temperature on granulosa cell apoptosis. Ovaries were held (1) at 20, 30 or 35-37 degrees C for up to 2h, (2) at 30 degrees C for 0-1, 1-2, 2-3, 3-4, 4-6 or 6-10h, and (3) granulosa cells were held for 0, 1, 2, 3, 5, 12 or 24h in M199 with Hank's salts at room temperature (suboptimal incubation). Granulosa cell DNA was analysed by ...
Ousey JC.The endocrine profiles in the periparturient mares are dominated by increasing concentrations of progestagens and decreasing oestrogens. These hormones are produced by precursors from the foetus, metabolized by the placenta and act primarily on the maternal uterus. The circulating concentrations of hormones in maternal plasma, generally, represent a small proportion of those metabolized by the foetus and utero-placental tissues. There is clear evidence that the foetal hypothalamo-pituitary-adrenal (HPA) axis initiates the process of foetal maturation and the hormonal cascade which culminates i...
Ing NH, Laughlin AM, Varner DD, Welsh TH, Forrest DW, Blanchard TL, Johnson L.In the testis of the 1.5-year-old horse, spermatogenesis initiates locally in grossly light, central areas that contrast with grossly dark, peripheral areas that are as yet inactive in spermatogenesis. Gene expression was compared between "light" and "dark" tissues of 1.5-year-old horse testes to identify mechanisms important to the initiation of spermatogenesis. Microarrays containing human cDNAs were used to assess expression levels of 9132 genes simultaneously in matched pairs of dark and light testis tissues from 3 prepubertal colts. In all 3 analyses, dysferlin (DYS), down-regulated in ov...
Briant C, Ottogalli M, Guillaume D.With the objective of controlling the day of ovulation, 40 mares were assigned to a control or three treated groups: A3d, A4d, and A5d. The treated groups received antarelix (Teverelix 0.01 mg/kg, i.v., twice a day) for 3, 4, or 5 days from the day the dominant follicle (F1) reached 28 mm (=D0), and one injection of hCG (1600 IU, i.v.) on D1, D2, or D3, respectively. Control mares received one injection of hCG when F1 reached 35 mm. Plasma LH, FSH, progesterone, and total estrogens were assayed. In the A3d, A4d, and A5d groups, 9 (90%), 6 (60%), and 5 (50%) out of 10 mares, respectively, ovula...
Kronfeld DS, Holland JL, Rich GA, Meacham TN, Fontenot JP, Sklan DJ, Harris PA.The digestibility of ether extract varies greatly from forages to grains and further to added fats consisting mainly of triglycerides. This variation has been attributed to two main factors, the presence of nonhydrolyzable substances in the ether extract, especially in leafy foods, and the dilution of endogenous fecal fat. A compilation of results from 188 equine digestion balance observations on five basal feeds and 18 test feeds with added fats demonstrated a true digestibility of fat approaching 100% and an endogenous fecal fat of 0.22 g x d(-1) x kg BW(-1). The results revealed that nonhyd...
van Doorn DA, Everts H, Wouterse H, Beynen AC.Availability of phytate-bound P as influenced by supplemental phytase was studied in eight horses consuming four diets in a 4 x 4 Latin square design experiment. The treatments were a control (containing a low P level, 18.4 g/d) and three high-P diets. These diets contained P as monocalcium phosphate (MCP; 43.7 g/d), myoinositol hexakisphosphate in the form of wheat and rice bran (MIHP; 41.8 g/d), or MIHP with microbial phytase (MIHPP; 42.5 g/d). The proportions of phytate-bound P were 3, 1, 55, and 56% for the control, MCP, MIHP, and MIHPP, respectively. The MIHPP diet was supplemented with 3...
Wu D, Murakami K, Liu N, Konishi M, Muneta Y, Inumaru S, Kokuho T, Sentsui H.The equine interleukin-18 (IL-18) cDNA that contains the coding sequence was cloned and a recombinant baculovirus, named AcEIL-18, was constructed. The recombinant protein of the equine IL-18 was expressed by AcEIL-18 and its expression was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Insect cells infected with AcEIL-18 secreted a precursor IL-18 with 24 kilo dalton (kDa) into the culture supernatant. Western blot analysis showed that mature equine IL-18 about 18 kDa was also confirmed without co-expression of caspase-1. Culture supern...
Kinnunen S, Hyyppä S, Lappalainen J, Oksala N, Venojärvi M, Nakao C, Hänninen O, Sen CK, Atalay M.Acute exercise induces oxidative stress and heat shock protein (HSP) expression. Information on the protection of stress proteins against oxidant insult and muscle damage during moderate exercise is scanty. We aimed to show how a single bout of moderate exercise affects the markers of oxidative stress and heat shock factor-1 (HSF1; the transcriptional regulator of HSP synthesis), and HSP70, HSP90 and glucose-regulated protein (GRP75) expression in horses. Eight clinically normal and regularly trained standardbred trotters were treadmill-exercised for 45 min at moderate intensity. Blood samples...
Dell'Aquila ME, Caillaud M, Maritato F, Martoriati A, Gérard N, Aiudi G, Minoia P, Goudet G.The aim of this study was to investigate cumulus expansion, nuclear maturation and expression of connexin 43, cyclooxygenase-2 and FSH receptor transcripts in equine cumuli oophori during in vivo and in vitro maturation in the presence of equine FSH (eFSH) and precursors for hyaluronic acid synthesis. Equine cumulus-oocyte complexes (COC) were cultured in a control defined medium supplemented with eFSH (0 to 5 micrograms/ml), Fetal Calf Serum (FCS), precursors for hyaluronic acid synthesis or glutamine according to the experiments. After in vitro maturation, the cumulus expansion rate was incr...
Velde K, Ross MW, Orsini JA, Parente EJ, Foley B, Richardson DW, Miselis RR.To study the fascicular anatomy of peripheral nerves, three different groups of retrograde axonal tracers were evaluated: fluorophores, horseradish peroxidase conjugated to subunit B of cholera toxin (CT-HRP), and adeno-associated virus (AAV). The hindlimb nerves in rats served as a model to identify the most efficient tracer in regard to labeling axons within peripheral nerves. The rat's tibial and common peroneal nerves were injected with the different tracers and the sciatic nerve was subsequently examined for evidence of labeled axons. The CT-HRP clearly provided the best results in this r...
Tomlinson JE, Wilder BO, Young KM, Blikslager AT.To examine the effects of flunixin meglumine and etodolac treatment on recovery of ischemic-injured equine jejunal mucosa after 18 hours of reperfusion. Methods: 24 horses. Methods: Jejunum was exposed to 2 hours of ischemia during anesthesia. Horses received saline (0.9% NaCl) solution (12 mL, i.v., q 12 h), flunixin meglumine (1.1 mg/kg, i.v., q 12 h), or etodolac (23 mg/kg, i.v., q 12 h). Tissue specimens were obtained from ischemic-injured and nonischemic jejunum immediately after ischemia and 18 hours after recovery from ischemia. Transepithelial electric resistance (TER) and transepithel...
Hosoya M, Inoue A, Kimura N, Arai T.Glucose, free fatty acid (FFA), triglyceride (TG) and immunoreactive insulin (IRI) concentrations in plasma and activities of enzymes related to energy metabolism in some types of peripheral leukocytes were measured in thoroughbred race horses before and after racing. Glucose, FFA, TG and IRI concentrations and enzyme activities did not change significantly in plasma. However, the activities of cytosolic hexokinase, malate dehydrogenase (MDH), mitochondrial MDH and aspartate aminotransferase decreased significantly in leukocytes of the horses after the races. The cytosolic ratio of MDH/LDH act...
Dunnett M, Richardson DW, Lees P.Hair analysis to detect drug administration has not been studied extensively in horses. This study aimed to (a) develop an analytical method for enrofloxacin and its metabolite ciprofloxacin in mane and tail hair, (b) relate measured values to doses, routes of administration, hair colour, and (c) demonstrate long-term detectability. Samples were extracted in trifluoroacetic acid at 70 degrees C. Extracts were cleaned-up by solid-phase extraction and analysed by high-performance liquid chromatography with UV-diode array detection. Analyte recoveries were > 87%. Horses were sampled after therape...
Raudsepp T, Santani A, Wallner B, Kata SR, Ren C, Zhang HB, Womack JE, Skow LC, Chowdhary BP.We herein report a detailed physical map of the horse Y chromosome. The euchromatic region of the chromosome comprises approximately 15 megabases (Mb) of the total 45- to 50-Mb size and lies in the distal one-third of the long arm, where the pseudoautosomal region (PAR) is located terminally. The rest of the chromosome is predominantly heterochromatic. Because of the unusual organization of the chromosome (common to all mammalian Y chromosomes), a number of approaches were used to crossvalidate the results. Analysis of the 5,000-rad horse x hamster radiation hybrid panel produced a map spannin...
Chopineau M, Martinat N, Gibrat JF, Galet C, Lecompte F, Foulon-Gauze F, Pourchet C, Guillou F, Combarnous Y.To identify amino-acids in the alpha-subunit important for expression of heterospecific FSH activity of horse (e) LH/choriogonadotropin (CG) (eLH) and donkey (dk) LH/CG (dkLH) (FSH/LH ratio ten times higher for eLH than for dkLH); this FSH activity absolutely requires an equid (donkey or horse) alpha-subunit combined with an equid beta-LH subunit. Methods: Chimeric alpha-subunits possessing the first 63 amino-acids of the porcine (p) and the last 33 amino-acids of the donkey alpha-subunit (alphap-dk) and the inverse (alphadk-p) were constructed. Porcine-specific amino-acids were introduced by ...
Kankavi O, Roberts MS.Once considered unique to the lung, surfactant proteins have been clearly identified in the intestine and peritoneum and are suggested to exist in several other organs. In the lung, surfactant proteins assist in the formation of a monolayer of surface-active phospholipid at the liquid-air interface of the alveolar lining, reducing the surface tension at this surface. In contrast, surface-active phospholipid adsorbed to articular surfaces has been identified as the load-bearing boundary lubricant of the joint. This raises the question of whether surfactant proteins in synovial fluid (SF) are re...
Ginther OJ, Gastal EL, Gastal MO, Bergfelt DR, Baerwald AR, Pierson RA.Deviation in growth rates of the follicles of the ovulatory wave begins at the end of a common growth phase and is characterized by continued growth of the developing dominant follicle (F1) and regression of the largest subordinate follicle (F2). Follicle diameters during an interovulatory interval were compared between 30 mares and 30 women, using similar methods for collecting and analyzing data. Follicles were tracked and measured daily by ultrasonography. Diameter at follicle emergence (mares, 13 mm; women, 6 mm) and the required minimal attained diameter for assessment of follicles (mares...
Ghaoui Rel-H, Thomson PC, Evans G, Maxwell WM.Membrane vesicles, separated by differential centrifugation from the seminal plasma, were detected in the sperm-rich ejaculate fractions of four boars and three stallions, and in the whole ejaculates of seven rams. The volume and percentage of vesicles, determined by a stereological technique, were higher in the sperm-rich than in the post-sperm-rich fractions of the boar and stallion ejaculates, and no vesicles were detected in the pre sperm-rich fractions. Vesicles were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). For boar, stallion and ram semen...
Lindström H, Mazari AMA, Musdal Y, Mannervik B.Equine glutathione transferase A3-3 (EcaGST A3-3) belongs to the superfamily of detoxication enzymes found in all higher organisms. However, it is also the most efficient steroid double-bond isomerase known in mammals. Equus ferus caballus shares the steroidogenic pathway with Homo sapiens, which makes the horse a suitable animal model for investigations of human steroidogenesis. Inhibition of the enzyme has potential for treatment of steroid-hormone-dependent disorders. Screening of a library of FDA-approved drugs identified 16 out of 1040 compounds, which at 10 μM concentration afforded at ...
Foreman JH, Benson GJ, Foreman MH.Horses generate considerable internal heat burdens when exercising. Although common practice for a trainer or groom to place a wet blanket or towel on the dorsum of a hot horse post exercise, there are no data supporting the efficacy of this cooling method. Objective: To test the hypothesis that a pre-moistened blanket designed with a multilayered breathable fabric would enhance heat loss in horses post exercise. Methods: Eight treadmill-trained horses performed a standardised exercise test (SET) weekly for 3 weeks, with 3 different recovery treatments administered randomly. Pulmonary artery t...
Bézard J, Mekarska A, Goudet G, Duchamp G, Palmer E.The objects of this study were to monitor the development of the cumulus complex and nuclear maturation in oocytes recovered from preovulatory follicles following treatment to induce ovulation and to investigate the in vitro maturation competence of oocytes recovered from smaller nonpreovulatory follicles of varying size. All follicles > or =5 mm in pony mares were individually punctured at 0, 6, 12, 24 and 35 h after an injection of LH to induce ovulation. The recovery rates of oocytes were 64% from 55 preovulatory follicles, 22% from 32 subordinate follicles and 52% from 227 small follicl...
Boere J, van de Lest CHA, de Grauw JC, Plomp SGM, Libregts SFWM, Arkesteijn GJA, Malda J, Wauben MHM, van Weeren PR.Extracellular vesicle (EV) concentration, characteristics and function in equine synovial fluid (SF) during normal growth and development has not previously been studied. Isolation of EVs was performed in SF from three healthy foals and two adult horses by differential ultracentrifugation (10,000g and 200,000g); EVs were purified by sucrose density gradient floatation and analysed by high-resolution flow cytometry (FCM), buoyant density and western blotting. Additionally, repeated biomarker analysis of sulphated glycosaminoglycans (GAG), matrix metalloproteinase (MMP), C-terminal crosslinked t...
Moslemi S, Vibet A, Papadopoulos V, Camoin L, Silberzahn P, Gaillard JL.Cytochrome P-450 aromatase was purified by five chromatographic steps from adult stallion testis. It was first separated from NADPH-cytochrome P-450 reductase (reductase) on omega-aminohexyl-Sepharose 4B then purified to homogeneity on concanavalin A-Sepharose 4B, hydroxyapatite-Sepharose 4B, DEAE-Sepharose CL-6B and on a second hydroxyapatite-Sepharose 4B. On the other hand, purifications of the equine testicular and rat liver reductases, which allowed the reconstitution of aromatase activity in vitro, were achieved for each species in one chromatographic step on an adenosine 2',5'-diphosphat...
Murray RC, Janicke HC, Henson FM, Goodship A.Processes involved in equine carpal osteochondral injury have not been established. In other species, fibronectin appears important in chondrocyte-matrix interactions, and levels are increased in osteoarthritis. This investigation aimed to (a) describe fibronectin immunoreactivity in the middle carpal joint of 2-year-old Thoroughbreds, (b) determine topographical variations, (c) compare strenuously trained (Group 1) or gently exercised horses (Group 2) and (d) describe sites with early osteoarthritis. Group 1 (n = 6) underwent a 19 week high intensity treadmill training programme. Group 2 (n =...
Sticker LS, Thompson DL, Bunting LD, Fernandez JM, DePew CL, Nadal MR.Twelve light horse mares were fed a control diet that provided 100% of their maintenance protein and energy requirements for 7 d and were then either continued on the control diet or totally deprived of feed (with access to water) for 3 d . Plasma samples were drawn twice daily throughout the experiment, at 15-min intervals for 9 h beginning 45 h after feed removal, and at 10-min intervals around an exercise bout beginning 73 h after feed removal. Feed deprivation increased (P < or = .06) whole blood beta-hydroxybutyrate and plasma NEFA, urea N, L-lactate, and glucagon concentrations, decrease...
Alves BG, Alves KA, Gastal GDA, Gastal MO, Figueiredo JR, Gastal EL.Comprehensive studies on spatial distribution of preantral follicles in the ovary are scarce. Considering that preantral follicles represent the main ovarian reserve, harvesting of these follicles is crucial for the development/use of assisted reproductive techniques. Therefore, knowledge on follicle spatial distribution can be helpful for targeting areas with richer number of preantral follicles through biopsy procedures. The aim of this study was to assess the distribution and localization of equine preantral follicles according to: (i) age, (ii) ovarian portion (lateral and intermediary) an...
Spensley MS, Carlson GP, Harrold D.During the growth interval encompassing age 2 days through 24 weeks, plasma, RBC, total blood, and extracellular fluid (ECF) volumes were determined in 7 healthy, resting foals. Evans blue dye and sodium thiocyanate were used to estimate plasma and ECF volumes, respectively. Absolute plasma volume remained stable from 2 days through 2 weeks of age, then increased progressively through 24 weeks of age. After decreasing between 2 days and 2 weeks of age, absolute RBC and total blood volumes progressively increased. Absolute ECF volume increased progressively from 2 days of age through 24 weeks o...
Manohar M.1. Transmural distribution of myocardial blood flow was studied using 15 micron diameter radionuclide-labelled microspheres in six normal ponies and nine splenectomized ponies at rest, and during maximal exercise performed without as well as with adenosine infusion (3 microM kg-1 min-1). The splenectomized ponies were also studied during submaximal exercise performed at 75% of the workload. 2. Maximal exertion in normal ponies increased heart rate (348%), mean arterial blood pressure (40.9%), rate-pressure product (563%), arterial O2 content (43.2%), and mean pulmonary artery pressure (247%). ...
Sheoran AS, Holmes MA.Equine IgG possesses four well-defined subisotypes, designated IgGa, IgGb, IgGc and IgG(T) on the basis of their increasing anodal mobility in electrophoresis. However, the preparation of IgGa and IgGb reference proteins has not previously been reported. Certain bacterial cell wall proteins, termed protein A and protein G, have been used for purification of IgG subisotypes from the serum of domestic animals which, combined with other techniques utilising differences in the physico-chemical properties of the proteins, has allowed the purification of Ig isotypes. This paper describes purificatio...
Riley SC, Thomassen R, Bae SE, Leask R, Pedersen HG, Watson ED.Profound hormonally controlled tissue remodelling occurs in the equine ovary for follicle growth and development, and also for the alteration in follicle shape directed towards the ovulation fossa, the site where ovulation occurs. The aim of this study was to examine the spatial and temporal regulation of matrix metalloproteinases (MMP)-2 and MMP-9, important enzymes in tissue remodelling, during follicle growth, and ovulation. Using gelatin substrate zymography, we measured these MMPs in follicular fluid of large anovulatory follicles collected during spring transition, early dominant follicl...
Alberghina D, Casella S, Giannetto C, Marafioti S, Piccione G.Serum protein electrophoresis (SPE) is a technique that could be considered one of the most useful diagnostic aids available to the clinician. The effect of storage time and temperature on the total proteins and electrophoretic fractions (albumin, α1-, α2-, β1-, β2-, and γ-globulins) was assessed in 24 healthy horses. All samples, collected by jugular vein puncture, were centrifuged and divided into 4 aliquots. The 1st aliquot was analyzed within 3 h from collection (time 0), the 2nd was refrigerated at +4°C for 24 h, the 3rd was refrigerated at +4°C for 48 h, and the last was frozen at...
Varner DD, Blanchard TL, Meyers PJ, Meyers SA.A breeding trial was conducted to evaluate the effect of in vitro storage time and temperature on fertilizing capacity of equine spermatozoa. Semen obtained from one stallion and diluted with skim milk-glucose extender was used to artificially inseminate 45 estrussynchronized mares. The mares were assigned to one of three treatment groups (15 mares per group): 1) insemination with fresh semen (collected within 0.5 h of use), 2) insemination with semen stored for 24 h at 20 degrees C or 3) insemination with semen stored for 24 h at 5 degrees C. The mares were inseminated daily during estrus, fr...
Lemazurier E, Toquet MP, Fortier G, Séralini GE.We used radioimmunoassay (RIA) to measure monthly serum levels of unconjugated and conjugated sex steroids (testosterone T, androstenedione A, estradiol E(2), and estrone E(1)) in 4 male and 4 female foals during their first year of life. Maximal production of sex steroids was detected from April to August with hormonal peaks, corresponding to the natural breeding season in adults. In males, only A levels were more steady. Total estrogens (unconjugated plus conjugated E(2) and E(1)) were the major steroids in immature males in contrast to adults. Estrogens generally peaked in young females bef...
Mawyer JD, Cavinder CA, Vogelsang MM, Sigler DH, Love CC, Brinsko SP, Blanchard TL, Varner DD, Arnold CE, Teague S, Gordon RK.Stallions (n = 8) were implanted with a thermal sensory device in the muscle of the neck and the subcutaneous tissue of the scrotum and then assigned to either a nonexercise (Non-EX; n = 4) or exercise (EX; n = 4) group. A motorized equine exerciser was used to work EX stallions 30 min/d for 4 d/wk during a 12-wk period from July through October 2010. Temperatures (subcutaneous scrotal, intramuscular neck, and rectal) were recorded at 0, 22, and 30 min after the start of exercise, as well as 60 and 120 min post-exercise. Hourly ambient temperature and relative humidity data were also obtained....
Meyer W, Kacza J, Hornickel IN, Schoennagel B.Using immunohistochemistry and transmission electron microscopy (TEM), the esophagus epithelia of seven domesticated mammals (horse, cattle, goat, pig, dog, laboratory rat, cat) of three nutrition groups (herbivorous, omnivorous, carnivorous) were studied to get first information about energy generation, as demonstrated by succinate dehydrogenase (SDH) activities. Distinct reaction intensities could be observed in all esophageal cell layers of the different species studied reflecting moderate to strong metabolic activities. The generally strong staining in the stratum basale indicated that new...
Bailly-Chouriberry L, Chu-Van E, Pinel G, Garcia P, Popot MA, André-Fontaine G, Bonnaire Y, Le Bizec B.Since the Australian commercialisation of the recombinant equine growth hormone (reGH) in 1998 (EquiGen-5), Bresagen), this reGH, which differs only from eGH by an additional methionine at the N-terminal end (met-eGH), is worldwide suspected to be administered to racehorses as a doping agent. Indeed, the use of this biological drug is considered as a threat to horseracing since it acts both on growth, development or reproductive functions, and on the improvement of performances. In this work, we describe two reliable techniques based on surface plasmon resonance biosensor immunoassay (SPR-BIA)...
Moura TCM, Arruda LCP, Araújo Silva RAJ, Silva RPF, Oliveira AS, Tobal LFM, Batista AM, Carneiro GF, Guerra MMP.The aim of this study was to investigate the effects of sucrose on post-thawed equine semen quality. Semen samples (n = 24) were collected from six stallions. They were diluted (200 × 10 sperm/mL) in a freezing medium based on skimmed milk, egg yolk, dimethylformamide, and supplemented with sucrose at concentrations of 0 (Control), 25, 50, and 100 mM and in a commercial extender (BotuCrio). Subsequently, they were filled in straws (0.5 mL) and subjected to freezing and storage (-196°C). Immediately after thawing (37°C, 30 seconds), semen samples were evaluated for kinetics (CASA), plasm...
Curtis RA, Kusano K, Evans DL.Locomotor-respiratory coupled (LRC) breath types are a feature of galloping exercise in horses. Differences in breath type have been demonstrated during exercise in particular the 'big respiratory cycle' (BRC) and 'flow hesitation'. To investigate breath types during recovery and quantitatively investigate BRCs during exercise to understanding the mechanism driving BRCs. Objective: To investigate the occurrence of different breath types during and after intense treadmill exercise, and test the hypothesis that large breaths (BRCs) were a function of respiratory frequency. Methods: Six trained a...
Lee Y, Kiupel M, Soboll Hussey G.Dendritic cells (DCs) are professional antigen-presenting cells that have multiple subpopulations with different phenotypes and immune functions. Previous research demonstrated that DCs have strong potential for anti-viral defense in the host. However, viruses including alphaherpesvirinae have developed strategies to interfere with the function or maturation of DCs, causing immune dysfunction and avoidance of pathogen elimination. The goal of the present study was to isolate and characterize equine lung-derived DCs (L-DCs) for use in studies of respiratory viruses and compare their features wi...
Saudek V, Atkinson RA, Williams RJ, Ramponi G.It has been proposed that combination of intraresidue, sequential and longer range nuclear Overhauser enhancements occurring in 1H nuclear magnetic resonance spectra of protein chains folded in a helix show a regular characteristic pattern. As a test case the spectra of horse muscle acylphosphatase were searched for this pattern together with other typical signs of a helical conformation (i.e. chemical shift, coupling constants and slow 2H-H exchange). Two amino acid sequences complying with these requirements were found. Just a few amino acid spin system assignments were then sufficient to lo...
Matthews AG.Three major antiprotease components in equine serum were identified and characterised. These were the acidic prealbumin Pr, the homologue of human alpha-1 antitrypsin and 2 protease binding proteins, the acidic prealbumin Xc and alpha-2 macroglobulin, both capable of inhibiting the proteolytic activity of trypsin, but with only limited inhibitory effect on its esterolytic activity. The possible role of these serum antiproteases in the onset of chronic obstructive pulmonary disease (COPD), analogous to the hereditary dysproteinaemia of alpha-1 antitrypsin in man, was investigated. There was no ...
Tokushige H, Kakizaki M, Ode H, Okano A, Okada J, Kuroda T, Wakuno A, Ohta M.To evaluate the bispectral index (BIS) as an indicator of anesthetic depth in Thoroughbred horses, BIS values were measured at multiple stages of sevoflurane anesthesia in five horses anesthetized with guaifenesin and thiopental following premedication with xylazine. There was no significant difference between the BIS values recorded at end-tidal sevoflurane concentrations of 2.8% (median 60 ranging from 47 to 68) and 3.5% (median 71 ranging from 49 to 82) in anesthetized horses. These BIS values during anesthesia were significantly lower (P<0.01) than those in awake horses (median 98 ranging ...
Mazan MR, Hoffman AM, Kuehn H, Deveney EF.To evaluate effects of sedation on stability of resistance of the respiratory system (RRS) and measures of resting energy expenditure (REE) by use of open-flow indirect calorimetry (IC) and treatment with aerosolized albuterol on REE in horses with recurrent airway obstruction (RAO). Methods: 9 clinically normal horses and 8 horses with RAO. Methods: In phase 1, RRS was measured by using forced oscillometry (FOT) in 5 clinically normal horses before and after sedation with xylazine. In phase 2, REE was measured in 4 clinically normal horses between 20 and 25 minutes and again 35 to 40 minutes ...
Krakowski L, Brodzki P, Krakowska I, Opielak G, Marczuk J, Piech T.The aim of the study was to determine the level of prolactin (PRL), serum amyloid A (SAA), and selected biochemical markers (T-Chol, AST, TP, Mg, P, and Ca) in the blood of mares during the perinatal period. The study involved 14 mares of the Polish Coldblood Horse breed, which were in the third trimester of pregnancy. Blood was collected for testing 2 weeks before parturition and then 24 hours after delivery and in the foal heat (9 days) and 9 days after ovulation and breeding. The research revealed significant differences in the level of PRL and SAA before and after delivery. The highest...
Väihkönen LK, Heinonen OJ, Hyyppä S, Nieminen M, Pösö AR.In red blood cells (RBC) of horses, both lactate-transport activity and lactate accumulation during races vary interindividually. To study whether similar variation in lactate transport is apparent also in RBCs of other racing species, blood samples were collected from 21 reindeer, 40 horses, 31 humans, and 38 dogs. Total lactate-transport activity was measured at 10 and 30 mM concentrations, and the roles of the monocarboxylate-transporter (MCT) and the inorganic anion-exchange transporter (band-3 protein) were studied with inhibitors. In the reindeer and in one-third of the horses, lactate t...
O'Reilly C, Zoller J, Sigler D, Vogelsang M, Sawyer J, Fluckey J.Despite the fact that horseback riding is a popular sport, there is little information available on horseback riding as a physical activity. The objective of this experiment was to quantify energy expenditure of participants (n=20) during three riding tests: a 45min walk-trot-canter ride (WTC), a reining pattern ride and a cutting simulation ride while wearing a telemetric gas analyzer. Total energy expenditure (tEE), mean and peak metabolic equivalents of task (MET), heart rate (HR), respiratory frequency (RF), relative oxygen consumption (relVO2), and respiratory exchange ratio (RER) were as...
Mutlib AE, Chui YC, Young LM, Abbott FS.The metabolic fate of xylazine, 2-(2,6-dimethylphenylamino)-5,6-dihydro-4H-1,3-thiazine, in horses is described. The major metabolites identified in the hydrolyzed horse urine were 2-(4'-hydroxy-2',6'-dimethylphenylamino)-5,6-dihydro-4H-1,3-thiazi ne, 2-(3'-hydroxy-2',6'-dimethylphenylamino)-5,6-dihydro-4H-1,3-thiazi ne, N-(2,6-dimethylphenyl)thiourea, and 2-(2',6'-dimethylphenylamino)-4-oxo-5,6-dihydro-1,3-thiazine. These metabolites were also produced by incubating xylazine with rat liver microsomes. The major metabolite produced in vitro by rat liver preparations was found to be the ring op...
Mukai K, Ohmura H, Takahashi Y, Kitaoka Y, Takahashi T.We investigated whether horses trained in moderate and mild hypoxia demonstrate greater improvement in performance and aerobic capacity compared to horses trained in normoxia and whether the acquired training effects are maintained after 2 weeks of post-hypoxic training in normoxia. Seven untrained Thoroughbred horses completed 4 weeks (3 sessions/week) of three training protocols, consisting of 2-min cantering at 95% maximal oxygen consumption under two hypoxic conditions (H16, F O = 16%; H18, F O = 18%) and in normoxia (N21, F O = 21%), followed by 2 weeks of post-hypoxic traini...
