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.
Bergero D, Préfontaine C, Miraglia N, Peiretti PG.The digestibility of horse feeds and rations can be determined using different techniques such as calculations based on the chemical composition, in vivo or in vitro methods. The marker methods overcome difficulties like discomfort for the animals and longer experimental times encountered using the ingesta/egesta method. In field conditions, a natural indigestible marker like acid-insoluble ash (AIA), with no changes in the normal ration, could be a very useful tool for digestibility trials. A group of six standardbred horses was used in a set of seven apparent digestibility trials. The diets ...
Wilsher S, Clutton-Brock A, Allen WR.A total of 78 day 10 horse embryos were transferred non-surgically to recipient mares that had ovulated 9, 7, 6, 5, 4, 3, 2 or 1 day after (negative asynchrony), on the same day (synchronous), or 2 or 4 days before (positive asynchrony) the donor (n=6 or 8 mares per group). Pregnancy rates between 100% (6/6) and 63% (5/8) were seen in recipient mares that were between +2 and -6 days asynchronous. Embryo survival to the heartbeat stage declined in recipients that were -7 days asynchronous and no embryos survived in recipients that were -9 days asynchronous. Irrespective of uterine asynchrony, c...
Nieto JE, MacDonald MH, Braim AE, Aleman M.Horses are exquisitely sensitive to bacterial endotoxin and endotoxaemia is common in colic cases. In this study, gene expression of inflammatory cytokines was characterised in the blood of healthy horses following i.v. administration of lipopolysaccharide (LPS). Six horses received an LPS infusion and 6 controls received an equivalent volume of saline. Gene expression of genes encoding interleukin (IL)-1alpha, IL-1beta, IL-6, IL-8, and tumour necrosis factor-alpha (TNF-alpha) was quantified by real-time PCR. Gene expression of all inflammatory cytokines was upregulated following administratio...
Schmidt A, Biau S, Möstl E, Becker-Birck M, Morillon B, Aurich J, Faure JM, Aurich C.It is widely accepted that transport is stressful for horses, but only a few studies are available involving horses that are transported regularly and are accustomed to transport. We determined salivary cortisol immunoreactivity (IR), fecal cortisol metabolites, beat-to-beat (RR) interval, and heart rate variability (HRV) in transport-experienced horses (N=7) in response to a 2-d outbound road transport over 1370 km and 2-d return transport 8 d later. Salivary cortisol IR was low until 60 min before transport but had increased (P<0.05) 30 min before loading. Transport caused a further marked i...
Ledbetter EC, Scarlett JM.To describe morphologic features, pachymetry and endothelial cell density of the normal equine cornea and limbus by in vivo confocal microscopy. Methods: Ten horses without ocular disease. Methods: The central and peripheral corneas were examined with a modified Heidelberg Retina Tomograph II and Rostock Cornea Module using a combination of automated and manual image acquisition modes. Thickness measurements of various corneal layers were performed and endothelial cell density determined. Results: Images of the constituent cellular and noncellular elements of the corneal epithelium, stroma, en...
Schmidt A, Möstl E, Wehnert C, Aurich J, Müller J, Aurich C.Based on plasma cortisol concentrations it is widely accepted that transport is stressful to horses. So far, cortisol release during transport has not been evaluated in depth by non-invasive techniques such as analysis of salivary cortisol and faecal cortisol metabolites. Transport also causes changes in heart rate and heart rate variability (HRV). In this study, salivary cortisol, faecal cortisol metabolites, heart rate and HRV in horses transported by road for short (one and 3.5 h) and medium duration (8 h) were determined. With the onset of transport, salivary cortisol increased immediately...
Wong BL, Kim SH, Antonacci JM, McIlwraith CW, Sah RL.To determine the effects of acute injury and tribosupplementation by hyaluronan (HA) on synovial fluid (SF) modulation of cartilage shear during tibio-femoral articulation. Methods: Human osteochondral blocks from the lateral femoral condyle (LFC) and tibial plateau (LTP) were apposed, compressed 13%, and subjected to sliding under video microscopy. Tests were conducted with equine SF from normal joints (NL-SF), SF from acutely injured joints (AI-SF), and AI-SF to which HA was added (AI-SF+HA). Local and overall shear strain (E(xz)) and the lateral displacement (Deltax) at which E(xz) reached ...
Yi J, Heinecke J, Tan H, Ford PC, Richter-Addo GB.It is now well-established that mammalian heme proteins are reactive with various nitrogen oxide species and that these reactions may play significant roles in mammalian physiology. For example, the ferrous heme protein myoglobin (Mb) has been shown to reduce nitrite (NO(2)(-)) to nitric oxide (NO) under hypoxic conditions. We demonstrate here that the distal pocket histidine residue (His64) of horse heart metMb(III) (i.e., ferric Mb(III)) has marked effects on the mode of nitrite ion coordination to the iron center. X-ray crystal structures were determined for the mutant proteins metMb(III) H...
Woodward AD, Holcombe SJ, Steibel JP, Staniar WB, Colvin C, Trottier NL.To test the hypothesis that AA transporter transcripts are present in the large intestine and similarly expressed along the intestinal tract, mRNA abundance of candidate AA transporter genes solute carrier (SLC) family 7, member 9 (SLC7A9), SLC7A1, SLC7A8, and SLC43A1 encoding for b(0,+)-type AA transporter (b(0,+)AT), cationic AA transporter-1 (CAT-1), L-type AA transporter-2 (LAT-2), and L-type AA transporter-3 (LAT-3), respectively, was determined in small and large intestinal segments of the horse. Mucosa was collected from the equine small (jejunum and ileum) and large intestine (cecum, l...
Lindner AE.The objective of the study was to examine the validity of v(4) [velocity run under the defined conditions inducing 4 mmol/L of blood lactate concentration ([LA])] and v(200) (velocity run under the defined conditions inducing a heart rate of 200 beats/min) to differentiate performance level among Standardbred racehorses. For this purpose, 19 Standardbred trotting racehorses with differing racing time records in 2 training yards were submitted to a standardized exercise test to determine their v(4) and v(200) (6 horses of one yard only). The test consisted of 4 or more consecutive intervals dep...
Mugnier S, Kervella M, Douet C, Canepa S, Pascal G, Deleuze S, Duchamp G, Monget P, Goudet G.Oviduct epithelial cells (OEC) co-culture promotes in vitro fertilization (IVF) in human, bovine and porcine species, but no data are available from equine species. Yet, despite numerous attempts, equine IVF rates remain low. Our first aim was to verify a beneficial effect of the OEC on equine IVF. In mammals, oviductal proteins have been shown to interact with gametes and play a role in fertilization. Thus, our second aim was to identify the proteins involved in fertilization in the horse. Results: In the first experiment, we co-incubated fresh equine spermatozoa treated with calcium ionophor...
Len JA, Jenkins JA, Eilts BE, Paccamonti DL, Lyle SK, Hosgood G.The objectives of this study were to determine the effects of centrifugation on equine sperm total and progressive motility, viability, and acrosomal integrity. We hypothesized that although high centrifugation forces would be detrimental to equine Equus caballus sperm, recovery rates would increase. Ejaculates from six stallions were collected, extended to a concentration of 25x10(6) cells/mL, and subjected for 10min to (1) no centrifugation (NC) or (2) centrifugation at 400xg, (3) 900xg, or (4) 4500xg. Before and after centrifugation (Day 0), and after 24h of cooling (Day 1), sperm motility ...
Laughlin AM, Welsh TH, Love CC, Varner DD, Parrish AR, Forrest DW, Ing NH.In vitro culture systems are valuable tools for investigating reproductive mechanisms in the testis. Here, we report the use of the precision-cut in vitro system using equine testicular slices. Testes were collected from immature light breed stallions (n=3) and cut into slices (mean slice weight= 13.85 ± 0.20 mg; mean slice thickness=515.00 ± 2.33 μm) using the precision-cut tissue-slicing method. Four tissue slices were placed on a grid floating on medium in individual vials. After a 1-h preincubation, they were exposed to medium containing ovine luteinizing hormone (oLH) at concentrations...
Schwab UE, Fulcher ML, Randell SH, Flaminio MJ, Russell DG.We describe a method for creating differentiated equine bronchial epithelial cell cultures that can be used for in vitro studies including airway disease mechanisms and pathogen-host interactions. Our method is based on the culturing of human tracheobronchial epithelial cells at an air-liquid interface (ALI) in specific serum-free, hormone-supplemented medium. Bronchial epithelial cells are isolated and grown on T-Clear® insert membranes. Within 2 to 3 wk, cells differentiate into ciliated and mucus producing cells as demonstrated by confocal and electron microscopy. Furthermore, the demonstr...
Bouwman FG, van Ginneken MM, Noben JP, Royackers E, de Graaf-Roelfsema E, Wijnberg ID, van der Kolk JH, Mariman EC, van Breda E.The major aim of the present study was to investigate the proteome of standardbred horses at different stages of training and intensified training. We searched for biomarkers using small skeletal muscle biopsies of live animals. 2D gel electrophoresis and mass spectrometry were successfully applied to investigate training-induced differential expression of equine muscle biopsy proteins. Despite the poor resolution of the equine genome and proteome, we were able to identify the proteins of 20 differential spots representing 16 different proteins. Evaluation of those proteins complies with adapt...
Suska M, Skotnicka E.The aim of this study was to examine the relationships between the concentrations of ATP, ADP, AMP (HPLC methods), total nucleotide pool (TAN), adenylate energy charge (AEC) and Na(+), K(+)-ATPase erythrocytic activities (by Choi's method) of horses as a function of breed and sex. The studies were conducted on 54 horses (stallions and mares) of different constitution types: breathing constitution (Wielkopolska and Hanoverian breed) and digestive constitution (Ardenian breed). Horse erythrocytes, independently of examined breed, present low ATP concentration in comparison to other mammal specie...
Laurencin D, Wong A, Chrzanowski W, Knowles JC, Qiu D, Pickup DM, Newport RJ, Gan Z, Duer MJ, Smith ME.Despite the numerous studies of bone mineral, there are still many questions regarding the exact structure and composition of the mineral phase, and how the mineral crystals become organised with respect to each other and the collagen matrix. Bone mineral is commonly formulated as hydroxyapatite, albeit with numerous substitutions, and has previously been studied by (31)P and (1)H NMR, which has given considerable insight into the complexity of the mineral structure. However, to date, there has been no report of an NMR investigation of the other major component of bone mineral, calcium, nor of...
Horohov DW, Adams AA, Chambers TM.It is widely recognized that advanced age is associated with alterations in immunological responses that likely contribute to increased morbidity and mortality in the elderly population. This decreased efficacy of the immune system with age is referred to as 'immunosenescence' and has been reported for a number of species. Similar age-related changes are seen in horses and are manifested as decreased responsiveness to vaccination in vivo and diminished proliferative responses to mitogens in vitro. The underlying mechanism responsible for these impaired immunological responses remains unknown. ...
Meyer W, Kacza J, Schnapper A, Verspohl J, Hornickel I, Seeger J.Based on cryo-SEM, standard and high resolution TEM, glycoconjugate histochemistry, and microbiological differentiation, the present study demonstrates the colonisation of the epithelium of the equine oesophagus with microorganisms. As particularly apparent using cryo-SEM to illustrate natural conditions, the present microbiota were clearly dominated by bacteria, forming a one-layer system, as attached to and embedded in concentrated mannose/mannan substances covering the outer stratum corneal cells. Bacterial numbers ranged from 5600 to 7200 per mm(2) in the central part of the oesophagus, th...
Leung GN, Tang FP, Wan TS, Wong CH, Lam KK, Stewart BD.This paper describes the application of gas chromatography-mass spectrometry (GC-MS) for in vitro and in vivo studies of 6-OXO in horses, with a special aim to identify the most appropriate target metabolite to be monitored for controlling the administration of 6-OXO in racehorses. In vitro studies of 6-OXO were performed using horse liver microsomes. The major biotransformation observed was reduction of one keto group at the C3 or C6 positions. Three in vitro metabolites, namely 6alpha-hydroxyandrost-4-ene-3,17-dione (M1), 3alpha-hydroxyandrost-4-ene-6,17-dione (M2a) and 3beta-hydroxyandrost-...
Faramarzi B, Thomason JJ, Sears WC.To quantitate changes in hoof wall growth and hoof morphology induced by mild exercise in Standardbreds. Methods: 18 Standardbreds. Methods: Horses were exercised at approximately 6 m/s (4,200 to 5,600 m/d) on 4 d/wk for 17 weeks. Both exercise (n = 9) and nonexercise (control group; 9) groups were housed in a large paddock throughout the study. At the beginning and end of the study, right forelimb feet of all horses were digitally photographed and underwent magnetic resonance imaging. Hoof wall measurements were obtained from the images to evaluate hoof wall growth and morphometric variables....
Riggs LM, Krunkosky TM, Noschka E, Boozer LA, Moore JN, Robertson TP, Peroni JF.To compare characteristics and enzymatic products of leukocytes detected in the skin and laminar tissues of horses administered black walnut heartwood extract (BWHE) and horses administered purified lipopolysaccharide (LPS). Methods: 25 healthy 5- to 15-year-old horses. Methods: Horses were randomly assigned to receive LPS (20 ng of O55:B5 Escherichia coli endotoxin/kg; n = 5) IV or 6 L of BWHE (10) or water (control group; 10) via nasogastric intubation. Horses were euthanatized 12 hours after treatment or at onset of Obel grade 1 lameness. Laminar tissue samples and skin samples from the mid...
de la Rebière de Pouyade G, Riggs LM, Moore JN, Franck T, Deby-Dupont G, Hurley DJ, Serteyn D.Laminitis is a local manifestation of a systemic inflammatory response that is characterized by neutrophil activation and movement of neutrophils into the laminar tissues. Given the evidence for the involvement of neutrophils in the development of laminitis, we measured concentrations of neutrophil elastase, a serine protease released from the azurophilic granules of neutrophils, in plasma, skin and laminar tissues obtained from control horses and horses given black walnut heartwood extract (BWHE) to induce laminitis. Healthy horses (5-15 years old) were randomly assigned to 4 groups: 3 experi...
Micera E, Albrizio M, Surdo NC, Moramarco AM, Zarrilli A.In this work the slaughter-linked plasma modifications of some stress-related hormones in horses subject to standardized butchering procedures were investigated in order to highlight the compromised animal welfare during pre-slaughter handling. During pre-slaughter, animals show strong hardship behavioural patterns, probably due to being under life-threatening conditions. Blood samples from 12 male horses, ageing from 3 to 5 years, were collected before slaughtering in lairage, and during exsanguination after stunning. Catecholamines, cortisol and beta-endorphin concentrations were assessed in...
Zerpa H, Berhane Y, Elliott J, Bailey SR.Cooling-enhanced contractile responses in cutaneous arteries have been reported to involve the activation of alpha(2C)-adrenoceptors, but their role in cutaneous veins is not clearly understood. The aim was to pharmacologically characterize the subtype of postsynaptic alpha(2)-adrenoceptors in the equine digital vein mediating contraction at two temperatures. The increase in isometric tension of endothelium-denuded equine digital vein in response to UK-14304 was studied in the absence and presence of relatively selective alpha(2)-adrenoceptor antagonists at temperatures of either 30 degrees C ...
Scarth JP, Spencer HA, Hudson SC, Teale P, Gray BP, Hillyer LL.In this study, the use of equine liver/lung microsomes and S9 tissue fractions were used to study the metabolism of the androgenic/anabolic steroid stanozolol as an example of the potential of in vitro technologies in sports drug surveillance. In vitro incubates were analysed qualitatively alongside urine samples originating from in vivo stanozolol administrations using LC-MS on a high-resolution accurate mass Thermo Orbitrap Discovery instrument, by LC-MS/MS on an Applied Biosystems Sciex 5500 Q Trap and by GC-MS/MS on an Agilent 7000A. Using high-resolution accurate mass full scan analysis o...
Van Weyenberg S, Buyse J, Kalmar ID, Swennen Q, Janssens GP.The relation between plasma leptin and daily ad libitum roughage intake was evaluated during a 14-day period in eight obese Shetland ponies. When the feeding strategy was changed from maintenance feeding to ad libitum feeding, feed intake increased the first day, decreased the second day and increased again during the following days to reach a constant level after 8 days. Plasma leptin concentration increased during the first 2 days, but remained constant afterwards. Although the same pattern was found in all ponies, the magnitude of the increase in leptin on day 1 and the resulting decrease i...
Revold T, Mykkänen AK, Karlström K, Ihler CF, Pösö AR, Essén-Gustavsson B.Muscular changes caused by training are breed-specific and studies on the Norwegian-Swedish Coldblooded Trotter (NSCT) are limited. Knowledge about lactate-transporters in muscle in this light draught breed used for harness racing is lacking. Objective: To identify muscular changes associated with training in young NSCTs and investigate muscular distribution of the monocarboxylate transporter 1 (MCT1) and its ancillary protein CD147, which facilitate lactate transport across membranes. Methods: Nine horses were followed from the start of their training period until the end of their 3-year-old ...
McCue PM.A wide variety of hormone therapies are used in clinical practice in the reproductive management of horses. The goal of this article is to review therapeutic options for a variety of clinical indications.
Schneider DA, Sayegh AI.There exists individual enteroendocrine cells spread throughout the gastrointestinal mucosa that release specific peptide, as well as nonpeptide, hormones to have various endocrine action on target cells bearing cell surface receptors selectively sensitive to these regulatory substances. Following receptor activation, a series of events is set into motion that serves to transduce the information imparted to the target cell. Such transduction mechanisms are numerous, and may be excitatory or inhibitory to the cell depending upon which G-protein subunits the receptor is coupled.
Berghaus LJ, Cathcart J, Berghaus RD, Hart KA.The vitamin D receptor (VDR)-vitamin D axis modulates pulmonary immunity in people but its role in equine immunity is unknown. Bacterial pneumonia causes high morbidity/mortality in foals and alveolar macrophages (AMφ) are important for pulmonary defenses. Age-related variations in vitamin D-mediated function of AMφ might contribute to the foal's susceptibility to pneumonia. Our aim was to assess the impact of age on equine vitamin D metabolism and VDR expression in AMφ. AMφ and plasma was collected from healthy foals (2, 4 and 8 weeks old) and adult horses (once). AMφ VDR expression was ...
Patterson SD, Bell K.Three cases of abnormal expression of the equine protease inhibitory alleles, Pi F, L, and S1, were observed following the examination of 30,000 plasma samples by one-dimensional acid (pH 4.6) polyacrylamide gel electrophoresis. Characterization of the abnormal proteins in terms of isoelectric point, molecular mass, inhibitory spectra, and sialic acid content was performed using one- and two-dimensional electrophoretic techniques. The Pi F and S1 abnormalities were postulated to be the result of amino acid substitutions causing alterations in the processing of the carbohydrate side chains. No ...
Meyer JC, Hunyadi LM, Ordóñez-Mena JM.Accuracy of baseline ACTH for the diagnosis of PPID in horses varies between studies. Objective: To estimate the diagnostic accuracy of ACTH as a biomarker for PPID in adult horses and appraise potential causes of heterogeneity. Methods: Systematic review and meta-analysis. Methods: A literature review identified studies reporting diagnostic accuracy data for extraction. Risk of bias was evaluated using QUADAS-2. Two random-effects models, the hierarchical summary receiver operating curve (HSROC) and the bivariate binomial normal model (BBN) were used to pool accuracy measurements. We performe...
Kawai S, Igarashi I, Abgaandorjiin A, Ikadai H, Omata Y, Saito A, Nagasawa H, Toyoda Y, Suzuki N, Matsuda H.In-vitro-propagated Babesia caballi parasites were examined by scanning and transmission electron microscopy. Many small pores were observed over the entire surface of infected erythrocytes on scanning electron microscopy, and on transmission electron microscopy these small pores were found to be openings of tubular structures. By the examination of a number of infected cells the tubular structures were found to be connected with the parasite, and this observation might indicate that the tubular structures arose the edge of the parasite and terminated at an Invagination on the surface of the e...
Doherty TJ, Andrews FM, Provenza MK, Frazier DL.The effect of sedation on gastric emptying was evaluated in six ponies by monitoring serum concentrations of acetaminophen (AP) after intragastric administration. Methods: Prospective randomized experimental study. Methods: Six adult ponies, 135 to 275 kg. Methods: Fifteen minutes after the intravenous administration of xylazine (1 mg/kg), butorphanol (0.05 mg/kg), acepromazine (0.05 mg/kg) or saline, ponies were given AP (20 mg/kg in 350 mL water) by stomach tube. Blood for AP analysis was collected at baseline and 15, 30, 45, 75, 90, 105, and 120 minutes after AP administration. The time (Tm...
Ghazi SR, Tadjalli M.The detailed coronary arterial anatomy of seven camels was studied and compared with that of horses and cattle. In camels, there is a bilateral coronary supply, the right coronary artery being the larger. The left coronary artery follows the same pattern as that in horses. The ramus collateralis proximalis in camels separates off some distance away from the origin of the ramus interventricularis paraconalis, as in horses, whereas it separates of very quickly in cattle. The ramus collateralis distalis has two branches in camels, whereas the left distal ventriculi ramus does not branch. The ramu...
Jansen MO, van den Bogert AJ, Riemersma DJ, Schamhardt HC.The load distribution over tendinous structures in the equine forelimb was studied by computing forces from in vivo signals of implanted liquid-metal strain gauges in 5 ponies. For validation, these tendon forces were converted to joint moments, which were summed and compared to the calculated joint moments caused by the ground reaction force. Mean peak forces per kilogram body weight (n = 5) amounted to 5.2 N/kg for the superficial digital flexor tendon, 3.8 N/kg for the deep digital flexor tendon, 7.3 N/kg for the distal accessory (check) ligament and 8.4 N/kg for the third interosseous musc...
Brummer M, Hayes S, Adams AA, Horohov DW, Dawson KA, Lawrence LM.Selenium status has been reported to affect immune function across many different species. Yet few studies have focused on the effect of Se status on the equine immune system. This study examined the effect of Se supplementation on vaccination response and immune function in mature horses. Twenty-eight horses were blocked by age and sex and were randomly allocated to 1 of 4 dietary treatment groups: low Se (LS), adequate Se (AS), Se-yeast (SP), and sodium selenite (SS). For 35 wk, horses allocated to LS, SP, and SS received a low-Se diet (0.06 mg/kg DM) with the intention to lower Se stores, w...
Wang T, Meng J, Yang X, Zeng Y, Yao X, Ren W.This study aimed to investigate the effects of training on cardiac structure and function, as well as plasma metabolite profiles in horses, in order to uncover the molecular regulatory mechanisms and cardiac remodeling under long-term exercise. We hypothesize that long-term standardized training induces physiological cardiac remodeling and differential metabolomic changes in Yili horses, which correlate with improved athletic performance. The study focuses on physiological exercise-induced cardiac remodeling, characterized by increased left ventricular wall thickness and chamber size. A total ...
Ferreira JC, Gastal EL, Ginther OJ.Transrectal color and power Doppler ultrasonography was used to study uterine blood flow and perfusion in mares with and without uterine cysts. Vascular perfusion of the uterus and blood flow velocities, vascular perfusion, diameter, circumference, and area of a cross section of the mesometrial attachment were evaluated. To study the effect of internal cysts, two matched groups (cystic and control, n=21 mares/group) were used. Uterine vascular perfusion in mares with cysts was less (P<0.0001) in the cystic than the noncystic region and less (P<0.0009) than that for controls. Mares with c...
Conti A, Godovac-Zimmermann J, Liberatori J, Braunitzer G.beta-Lactoglobulin-like proteins were detected in horse colostrum and normal milk using immunological techniques. In contrast to the beta-lactoglobulins sequenced so far these proteins are monomeric and genetically not homogenous. In this paper we report the first primary structure of a monomeric beta-lactoglobulin from horse colostrum. By means of an automatic liquid-phase sequenator the sequence of peptides obtained by tryptic digestion and by cyanogen bromide cleavage was determined. A limited tryptic digestion and hydrolysis with chymotrypsin provided the necessary overlapping peptides. Th...
Science (New York, N.Y.)March 3, 1972
Volume 175, Issue 4025 996-997 doi: 10.1126/science.175.4025.996
Gershon RK, Kondo K.Mice rendered tolerant to sheep red cells and then given normal thymocytes, made no antibody when immunized with these cells. When immunized with horse red blood cells, however, they made significant amounts of noncross-reacting antibody to sheep red blood cells. This suggests that antibody-making precursor cells (B cells) which are nontolerant but nonactivatable by specific antigen, may exist in tolerant hosts.
Hunter DJ, Macmaster R, Roszak AW, Riboldi-Tunnicliffe A, Griffiths IR, Freer AA.Equine P2 protein has been isolated from horse spinal cord and its structure determined to 2.1 A. Since equine myelin is a viable alternative to bovine tissue for large-scale preparations, characterization of the proteins from equine spinal cord myelin has been initiated. There is an unusually high amount of P2 protein in equine CNS myelin compared with other species. The structure was determined by molecular replacement and subsequently refined to an R value of 0.187 (Rfree=0.233). The structure contains a molecule of the detergent LDAO and HEPES buffer in the binding cavity and is otherwise ...
Saulez MN, Cebra CK, Tornquist SJ.Alkaline phosphatase (ALP) is an enzyme present in intestinal mucosa, bile, bone, and renal tubule cells. We sought to assess the diagnostic and prognostic relationships of total ALP (ALPt) activity and that of intestine-derived ALP (ALPi) in serum and peritoneal fluid of 126 horses with colic. ALPt and ALPi activities were measured in both serum and peritoneal fluid by using both standard and L-phenylalanine-based buffers, respectively. Neither ALPt nor ALPi activity were useful in classifying type or severity of intestinal damage. ALPt and ALPi activities in peritoneal fluid were lowest in h...
Lin G, Chen GH, Ho HC.Conformationally restricted carbamate inhibitors, exo-2-norbornyl-N-butylcarbamate (1), endo-2-norbornyl-N-butylcarbamate (2), l-adamantyl-N-butylcarbamate (3), and 2-adamantyl-N-butylcarbamate (4) as active site-directed irreversible inhibitors of horse serum butyrylcholinesterase are investigated for values of the dissociation constant (KI), the carbamylation constant (k2), and the bimolecular rate constant (ki). Compound 1 is the most potent inhibitor of the enzyme and the values of KI and ki are 20 nM and 1.1 x 10(5) M-1sec-1, respectively.
Shaw EB, Houpt KA, Holmes DF.Average daily core body temperature and behavioural patterns of pregnant mares were studied, in search of definitive signs of parturition within 24 h of the event. Nineteen pony mares were sampled twice daily for core body temperature. A significant temperature drop, averaging 0.1 degrees C (0.2 degrees F) was observed during the day prior to parturition. Between 18.00 h and 06.00 h, during the two weeks before parturition, Thoroughbred and Standardbred mares (n = 52) spent an average 66.8 per cent of their time standing, 27.0 per cent eating, 4.9 per cent lying in sternal recumbency, 1.0 per ...
McDowell KJ, Sharp DC, Fazleabas AT, Roberts RM.Conceptuses were obtained from pony mares on each day of pregnancy between Days 12 and 28, and on Days 39, 45, 65 and 100. Endometrium was obtained from mares at Days 12, 14, 16, 18, 39, 45, 65 and 100 of pregnancy, and from non-pregnant mares during anoestrus, during transition into the breeding season, at oestrus, or during dioestrus. Tissues were incubated in vitro for 24 h with L-[3H]leucine. Proteins synthesized and released into the culture medium were analysed by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and fluorography. Conceptuses obtained before Day 14 after ovul...
Ferrante A, Thong YH.Results presented show that highly purified populations of mononuclear (MN) and polymorphonuclear (PMN) leucocytes can be obtained from horse blood by a procedure similar to that previously described for the separation of these leucocytes from human blood. This involved centrifugation of horse blood on a Ficoll-Hypaque medium with a density of 1.095 g/ml. The procedure required approximately 1 h for completion and resulted in the simultaneous preparation of MN (greater than 98% purity) and PMN (greater than 96% purity) leucocytes. Cell viability exceeded 95% and cells retained immunological fu...
Berryhill EH, Magdesian KG, Tadros EM, Edman JE.Maintaining serum glucose concentrations is critical in neonatal foals and is often dysregulated in illness; however, few studies have assessed the effects of age, or variation of glucose and insulin, in neonates and their postpartum dams. This study aimed to serially evaluate serum glucose and insulin concentrations and glucose/insulin (G/I) ratios in seven healthy foals and their dams immediately postpartum and at 1-2 and 10-12days of age. The hypotheses were that: (1) there would be wide temporal variation in hourly glucose and insulin measurements among foals; and (2) measured parameters i...
Berndtson WE, Squires EL, Thompson DL.The influence of season on spermatogenesis, testicular composition and the concentration of testosterone in the equine testis was evaluated using testes from 45 stallions. Testes were obtained through a commercial abbatoir during September, December-January, March and July. The weights of the testes, the tunica albuginea and testicular parenchyma and the proportion of the testicular parenchyma occupied by seminiferous tubules or interstitial tissue were similar during each season. How ever, diameter of the seminiferous tubules was greater in July than during other months of the study. In addit...
Persson SG, Funkquist P, Nyman G.The purposes of this study were to elucidate the influences of age and sex on the mass specific blood volume parameters: total blood volume (TBV/BW, ml/kg), plasma volume (PV/ BW, ml/kg), total red cell volume (CV/BW, ml/kg) and maximal packed cell volume (PCV, l/l, i.e. after total mobilisation of the splenic red cell reservoir) and to establish reference values for these in normally performing Standardbred trotting race horses. In total 205 horses were studied. They were all, according to their owners and/or trainers, performing satisfactorily in racing or training for shortly impending raci...
Bennett-Wimbush K, J SB, Amstutz M, Duthie M.Three sequential studies were performed to evaluate the effects of tying horses while wearing overchecks (strap from the bridle to backpad). In an observational study, horses (n = 305) wore high (HC), low (LC), or no overchecks (NC) with frequencies of 29.2%, 51.8% and 19.0% respectively. Study 1 (Latin square, n = 6) consisted of a 90-min tie test (90TT) with treatments (HC, LC, NC) x periods (1-3). Horses wearing HC had higher plasma cortisol (P < 0.01) when compared to LC and NC. Muscle soreness (MSS) and tightness (MTS) were evaluated pre and 24 hr post 90TT and were higher (P <...
Vidament M, Magistrini M, Le Foll Y, Levillain N, Yvon JM, Duchamp G, Blesbois E.This study tested whether variable temperatures (from -0.5 to 15 °C) and air exposure could be used under laboratory and under field conditions to store stallion sperm diluted in extender INRA96 without loss of fertility. Experiment 1 (laboratory conditions) measured the effects of two 72 h storage conditions (5 °C with air vs. 15 °C without air). Experiment 2 (fixed field conditions) measured the effects of 22 h of storage without air in disposable containers maintained at four ambient temperatures (7 °C, 17 °C, 27 °C, 39 °C with semen at -0.5 °C to 3 °C, 4 °C to 7 °C, 8 °C to 10 ...
Hirsbrunner G, Reist M, Couto SS, Steiner A, Snyder J, Vanleeuwen E, Liu I.Uterine smooth muscle specimens were collected from euthanatized mares in estrus and diestrus. Longitudinal and circular specimens were mounted in organ baths and the signals transcribed to a Grass polygraph. After equilibration time and 2 g preload, their physiologic isometric contractility was recorded for a continuous 2.0 h. Area under the curve, frequency and time occupied by contractions were studied. Differences between cycle phases, between muscle layers, and over the recorded time periods were statistically evaluated using linear mixed-effect models. In the mare, physiologic contractil...
Mlodawska W, Slomczynska M.Ovarian steroidogenesis from the neonatal to pubertal period in horses is poorly understood. This study was designed to immunolocalize cytochrome P450 aromatase in the ovarian follicles of slaughtered fillies ages approximately (I) 6-9 mo (5 mm in diameter. Staining intensity was dependent on the size and morphology of the follicle. In nonatretic follicles 5-10 mm in diameter, the reaction was weak and heterogeneous, while most intense staining was observed in preovulatory follicles. In follicles (diameter <20 mm) in the groups <10MF and 1YF, the reaction was less intense than in adult m...
