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.
Squires EL, McKinnon AO, Carnevale EM, Morris R, Nett TM.For embryos collected from mares 7 days after ovulation, embryo recovery for single-ovulating mares was 53% compared to 106% for double-ovulating mares. Pregnancy rates 50 days after surgical transfer were 68 and 129%, respectively. Concentrations of LH were similar during the periovulatory period for cycles which included single or double ovulations. Horse pituitary extract given for 5.5 days resulted in greater than or equal to 2 ovulations (mean 3.8) in 26 of 28 mares and 2.0 embryos were recovered per donor compared to 0.65 for controls. Non-surgical pregnancy rates for embryos collected f...
Charbord P, Tippens D, Wight TS, Gown AM, Singer JW.This report describes an IgG1 mouse monoclonal antibody derived after immunization of mice with washed stromal cells from human, long-term bone marrow cultures. The antigen recognized by the antibody (BMS-1) is a carbohydrate-containing prosthetic group that is common to and specific for multiple horse serum proteins. These proteins are avidly ingested by stromal cells and concentrated in endocytic vesicles. Cultured smooth muscle cells took up the horse proteins in a similar manner to marrow stromal cells while cultured marrow fibroblasts, endothelial cells, and hepatoma cells did not. These ...
Morris DD, Moore JN.Equine peritoneal macrophages were isolated and cultured in vitro to assess their ability to produce thromboxane (TxA2) and prostacyclin (PGI2) in response to endotoxin. Peritoneal macrophages (2.5 x 10(6)/ml) were incubated in tissue culture media, containing 1) no additive (nonstimulated control), 2) endotoxin (0.5 to 100 ng/ml) or 3) the calcium ionophore, A23187 (0.95 microM) for two and six h. Concentrations of the stable metabolites of TxA2 and PGI2 thromboxane B2 (TxB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), in the incubation media were determined by radioimmunoassay. Th...
Saltiel A, Gutierrez A, de Buen-Llado N, Sosa C.After parturition, Thoroughbred mares were mated at the first post-partum oestrus (N = 24) or at a subsequent oestrus (N = 12). All mares were examined daily for: oestrous detection, palpation per rectum of the genital tract, vaginoscopic examination and cervico-endometrial cytology. Pregnancy diagnosis was carried out at Days 18, 35 and 45 after mating. An identical first service conception rate of 50% was found in both groups. The number of neutrophils followed a descending profile to only scattered cells at the first post-partum oestrus and in Group II mares remained at this very low level ...
Thomas WP, Madigan JE, Backus KQ, Powell WE.Cardiopulmonary function was studied in 10 full-term healthy foals from birth to 14 days of age. Systemic and pulmonary haemodynamics were recorded in lateral recumbency via indwelling aortic and pulmonary artery catheters. Mean body weight increased from 45.4 +/- 2.4 kg on Day 1 to 70.6 +/- 6.1 kg on Day 14. All foals had a continuous murmur of patent ductus arteriosus for 3-6 days. From Day 1 (12 h old) to Day 14, heart rate increased (89 +/- 4 to 95 +/- 5/min), mean aortic pressure increased (87.7 +/- 1.9 to 100.3 +/- 3.2 mmHg), mean pulmonary artery pressure decreased (38.6 +/- 4.6 to 27.4...
Ducharme NG, Burton JH, van Dreumel AA, Horney FD, Baird JD, Arighi M.The nutritional implications and adaptive processes resulting from resection of 75% of the length of the large colon in ponies were investigated. Ten ponies in good physical condition were divided into two groups: six in the experimental group and four in the control group. During the sixth postoperative month, two digestibility studies were conducted, and phosphate fractional renal excretion and serum biochemical profiles were determined in both groups. The ponies (N = 10) were euthanized six months postoperatively, and gross and histopathological examinations were performed. Results of the s...
Murphy CJ, Howland HC.One factor peculiar to the practice of comparative ophthalmoscopy is the very large variation in ocular size of the animals examined, a factor which is ignored in current textbook treatments of the subject. We have computed values of lateral magnification, axial magnification, angular field of view and linear field of view for 19 species of terrestrial vertebrates. The dimensional value of a 1 diopter change in direct ophthalmoscopic focus was also determined. The anterior focal length of the eye in air and the vitreal refractive index were the intrinsic optical parameters of the animal's eye ...
Wood JM, Baum HP, Bews JP, Wachsmuth ED, Heusser C, Hofbauer KG.In this study, the hypotensive efficacy of R-3-36-16, a monoclonal antibody against human kidney renin, was investigated during chronic administration to a primate. R-3-36-16 was given by continuous intraperitoneal infusion with osmotic minipumps to normotensive marmosets fed a low-sodium diet in doses of 30 or 300 micrograms/kg/day for 14 days. The lower dose had no effect on blood pressure (BP) or plasma renin activity (PRA). After two days of treatment, the higher dose reduced PRA by 57% and lowered BP by 13 +/- 7 mm Hg. Although the hypotensive response persisted after 14 days of treatment...
Allen D, White NA, Foerner JF, Gordon BJ.Thirteen horses with chronic refractory laminitis were evaluated and treated. In each horse, deep digital flexor tenotomy was performed on all affected limbs at the level of the midpastern. Five horses returned to limited athletic endeavors, 6 horses improved and were comfortable on pasture, 1 horse improved clinically, but was euthanatized for economic reasons, and 1 horse improved, but deteriorated 9 months after surgery and was euthanatized. Results of this study indicated that deep digital flexor tenotomy at the level of the midpastern can be used effectively as a salvage procedure in hors...
Rutten DR, Chaffaux S, Valon M, Deletang F, De Haas V.In two studies in Holland and France a total of 41 mares found either to be in anoestrus or showing continuous oestrous behaviour during the early part of the covering season were treated with a progesterone releasing intravaginal device. Of the 32 mares in the first study, 24 ovulated after treatment and 11 became pregnant to a covering at the induced oestrus. In the second study all but one of the nine mares showed oestrus, seven ovulated and six became pregnant at the post treatment oestrus. By the end of the covering season 15 of the 21 mares treated for anoestrus and seven of the 11 mares...
Mahaffey EA, Moore JN.In vitro erythrocyte agglutination developed in 3 hospitalized horses receiving heparin treatment. The agglutination caused artifactual decreases in erythrocyte counts and increases in mean corpuscular volume (MCV) values. Treatment of cell suspensions with trypsin eliminated the agglutination and the changes in erythrocyte count and MCV. Similar abnormalities in erythrocyte counts and MCV have been reported in healthy horses treated with heparin and have been cited as evidence of hemolysis and regenerative anemia.
Schamhardt HC, Merkens HW, Lammertink JL.Software for analysis of force plate recordings of the horse at normal walk is described. The data of a number of stance phases are averaged to obtain a representative tracing of that horse. The amplitudes of a number of characteristic peaks in the force-time curves are used to compare left and right front limbs and left and right hind limbs. The averaged tracings are plotted, default on the line printer or, via separate program, on a high quality pen plotter. A version of the program applicable for analysis of human force plate recordings, is available.
Voith VL.This article discusses some general principles of learning as well as possible constraints and how such principles can apply to horses. A brief review is presented of experiments that were designed to assess learning in horses. The use of behavior modification techniques to treat behavior problems in horses is discussed and several examples of the use of these techniques are provided.
Dallaire A.Behavioral and physiologic characteristics of sleep are described, with special attention paid to equids. Temporal organization of sleep and environmental influences upon this behavior in horses are reviewed. Anatomic and biochemical bases and function of sleep are discussed briefly.
Liu IK, Cheung AT, Walsh EM, Ayin S.The functional competence of uterine-derived polymorphonuclear neutrophils (PMNs) from 28 mares was measured for migration responsiveness by use of a chamber (filter) assay. Uterine infection was induced with Streptococcus zooepidemicus in mares considered resistant to chronic uterine infection (Grade I). In sequential analysis of uterine flushings obtained from these mares 5, 12, 15, 20, and 25 h after infection was induced, PMNs showed an initial rise at 12 h (from 5), then a general decline in migration response and in concentration of cells per ml from 12 through 25 h post-inoculation. In ...
Snyder JR, Pascoe JR, Holland M, Kurpershoek CJ.Measurements of jejunal, ileal, and large colon (pelvic flexure) surface O2 tension (PSO2) were made in halothane-anesthetized horses with a nonheated miniature oxygen polarographic electrode. Assisted ventilation with 100% O2 was used to maintain PaCO2 tension at 50 +/- 8 mm of Hg while mean arterial blood pressure was maintained greater than or equal to 70 mm of Hg. Mean +/- SD PSO2 for the intestinal segments were: jejunum (horses 1 to 4), 71 +/- 20 mm of Hg; ileum (horses 1 to 4), 61 +/- 8 mm of Hg; and pelvic flexure of the large colon (horses 1 to 10), 55 +/- 13 mm of Hg. The response of...
Adeyefa CA.The effects of the various growth factors with regard to the nutritional physiology of zoophilic dermatophytes isolated from horses are reported. The optimum temperature, pH and growth period for the fungal isolates were found to be 30 degrees-35 degrees C, 5-6 and 7-12 days respectively while the carbon and nitrogen sources utilised by the organisms were sucrose, fructose, maltose, L-arginine and calcium nitrate. The use of these factors in preparation of efficacious fungicides used in the treatment of ringworm infections in man and animals is discussed.
Johnson AL.Cycling standardbred mares were infused with saline or 20 micrograms gonadotropin-releasing hormone (GnRH) in a pulsatile pattern (one 5-sec pulse/h, 2 h or 4 h) beginning on Day 16 of the estrous cycle. Although serum concentrations of luteinizing hormone (LH) increased significantly earlier in all three GnRH-treated groups (within one day of the initiation of infusion) compared to saline-infused controls, there were no differences in peak periovulatory LH concentrations among treatments (overall mean +/- SEM, 8.98 +/- 0.55 ng/ml). The number of days from the start of treatment to ovulation w...
Spensley MS, Baggot JD, Wilson WD, Hietala SK, Mihalyi JE.Plasma and endometrial tissue concentrations of ticarcillin were measured in healthy mares. In the first of the 3 separate phases comprising the study, ticarcillin disodium (30 mg/kg) was administered IV. The mean peak concentration in endometrial tissue, 12.9 micrograms/g, was attained at 30 minutes. The plasma half-life of the drug in the 6 mares was 0.83 +/- 0.22 hour. Six grams of the drug was diluted in 250 ml of sodium chloride injection USP (2nd phase) and in 60 ml of sodium chloride injection USP (3rd phase). These dilutions were administered by intrauterine infusion. In phase 2, the m...
Houghton E, Dumasia MC, Teale P, Moss MS, Sinkins S.Esters of 19-nortestosterone form an important group of anabolic preparations used in veterinary practice. Based upon results from detailed metabolic studies for 19-nortestosterone in the horse, a method to confirm the administration of anabolic preparations of this steroid to castrated male horses and fillies is described; the method is based upon the use of multiple analytes. Following administration of the anabolic preparations, solid-phase extraction of urinary conjugates and the separation of the conjugate groups prior to hydrolysis allow for the determination of specific metabolites conj...
Pellegrini A, Hägeli G, von Fellenberg R.Addition of perchloric acid (6.4% w/v final concentration) to horse alpha 1-proteinase inhibitor or to horse plasma neither precipitated nor inactivated alpha 1-proteinase inhibitor. None of the isoinhibitors of alpha 1-proteinase inhibitor was altered by dilute perchloric acid. This unexpected behavior led to a simplified procedure for the purification of horse alpha 1-proteinase inhibitor, consisting of removal of the bulk of plasma proteins, by perchloric acid precipitation and by gel filtration on Sephadex G-75 and G-200. The resulting preparations of alpha 1-proteinase inhibitor were immu...
Granon S.Pig and horse colipases contain three tyrosine residues. In addition, horse colipase possesses a tryptophan residue. Some of the tyrosine residues are involved in the association of colipase and a bile salt micelle. The present report demonstrates that the aromatic residues responsible for colipase fluorescence are in an aqueous environment. In the presence of bile salt micelles, changes in colipase fluorescence properties indicate that the intrinsic fluorophores are located in a more hydrophobic environment upon colipase-micelle complex formation. In addition, the fluorescence of an NBD group...
Rose RJ.Over the last 10 years, there has been a great increase in information on the physiological effects of endurance exercise in horses reflecting the increase in popularity of endurance riding throughout the world. This review, which is in two parts, examines energy considerations, fluid and electrolyte balance, acid-base balance, hormonal and metabolic changes, muscle function, renal and hepatic function, haematological changes and clinical problems encountered in endurance rides. Additionally, relevant information from studies in man is included.
Cahill JI, Goulden BE.This study confirmed that neurogenic muscle pathology exists in intrinsic laryngeal muscles supplied by the recurrent laryngeal nerves in horses subclinically and clinically affected with laryngeal hemiplegia. An important additional observation was the occurrence in three out of four laryngeal hemiplegic horses of neurogenic muscle changes in a hindlimb muscle, the extensor digitorum longus, a muscle supplied by another long peripheral nerve. This finding suggests that a polynenropathy exists in laryngeal hemiplegic horses, and supports the classification of this disease as a distal axonopath...
Sexton WL, Erickson HH.Cardiopulmonary responses of four ponies were monitored during standard exercise tests (SET), before and after beta-adrenergic receptor blockade with propranolol. The SET consisted of four 5 min increments of increasing speed from 1.0 to 2.8 m/sec on a treadmill at a 7 degrees incline. Data were collected at rest, throughout the SET and recovery. Administration of propranolol to ponies at rest had no effect on cardiopulmonary function. During the SET, increases in heart rate, mean pulmonary artery flow velocity (an index of cardiac output) and right ventricular dP/dt (an index of myocardial co...
Franco RM, Ousey JC, Cash RS, Rossdale PD, Silver M.An electronic sphygmomanometer which functions on oscillometric principles, was used to measure arterial blood pressure in foals. Its accuracy was assessed by comparison with results obtained by direct measurement in anaesthetised pony foals, aged 34 to 64 days. Correlations between data obtained by the two methods were highly significant but the sphygmomanometric readings were consistently lower than those obtained by direct measurement. An equation was derived from the pooled values for mean, systolic and diastolic pressure measurements. This was used as a correction factor when the oscillom...
Teijeiro JM, Marini PE.The oviduct is a dynamic organ in which final gamete maturation, fertilization and early embryo development take place. It is considered to be a sterile site; however the mechanism for sterility maintenance is still unknown. S100A7 is an anti-microbial peptide that has been reported in human reproductive tissues such as prostate, testicle, ovary, normal cervical epithelium and sperm. The current work reports the presence of S100A7 in the Fallopian tube and its localization at the apical surface of epithelial cells. For comparison, porcine S100A7 was used for antibody development and search for...
HARDY FM, ARBITER D.Hardy, Frank M. (Fort Detrick, Frederick, Md.), and David Arbiter. Lipid inclusions in L cells associated with Venezuelan equine encephalomyelitis virus infection. J. Bacteriol. 89:1101-1103. 1965.-Venezuelan equine encephalomyelitis (VEE) virus has been shown to induce changes of lipid components within the L cell. Lipid inclusions in the form of dark granular bodies were observed in the L cell after aqueous osmium tetroxide fixation and Sudan black staining. Microscopic examination of cells as early as 8 hr after infection with VEE virus showed an increase in the concentration of these inclu...
Peters GJ, Oosterhof A, Veerkamp JH.1. Activity of uridine kinase was very low in ovine lymphocytes and in those of some pigs. Lymphocytes of other pigs showed a significantly higher activity of this enzyme. Activity of uridine kinase in lymphocytes of man, horse and cattle was intermediate. 2. Activity of uridine phosphorylase was higher than that of uridine kinase with lymphocytes of all species. 3. Activity of uridine kinase in equine lymphocytes increases at PHA-stimulation and also in porcine lymphocytes with a low activity at the start of the culture. Activity of uridine kinase decreased in porcine lymphocytes with a high ...
Ginther OJ, Gastal EL, Gastal MO, Beg MA.The role of the insulin-like growth factor (IGF) system in the deviation in growth rates among follicles (follicle selection) was studied in mares using an IGF binding protein (BP) to reduce the follicular-fluid concentrations of IGFs. The future dominant follicle (F1) was treated by intrafollicular injection at the expected beginning of deviation (F1 > or = 20 mm; Day 0). The experimental groups were control (no injection, n = 8), vehicle (injection of vehicle; n = 6), and BP (injection of 250 microg of recombinant human IGFBP-3; n = 6). A sample of follicular fluid was taken from F1 on Da...
Jones CJ, Enders AC, Wooding FP, Dantzer V, Leiser R, Stoddart RW.Using lectin histochemistry on plastic-embedded material, the glycosylation patterns of equine girdle and cup cells, and associated endometrial glands, have been investigated from 37 to 67 days gestation. Results were compared with the glycosylation of the 50-day allantochorionic trophoblast of the established equine placenta that will later form the microcotyledons. The differentiated cup cells, which secrete equine chorionic gonadotropin (eCG), showed a pattern of glycosylation that was distinct both from the progenitor girdle cells and the allantochorionic trophoblast, with granules that bo...
Freeman DA, Butler JE, Weber JA, Geary RT, Woods GL.Oviductal and uterine embryos were collected from mares at 5 to 7 days following ovulation 1) to evaluate the effects of oviductal tissue explants on in vitro growth and development of equine embryos and 2) to study the morphologic development of equine embryos in culture. Embryos were incubated for 5 days in a medium (control group) or in medium supplemented with oviductal tissue explants (co-culture group). Embryos were evaluated and the media changed daily. Following 5 days in culture, 10 10 (100%) control embryos and 27 29 (93%) co-cultured embryos had doubled in diameter. All embryos that...
Goericke-Pesch S, Hauck S, Failing K, Wehrend A.Membrane vesicles (MVs) in the ejaculate have been identified in various species and are considered to affect membrane fluidity due to their characteristic molecular composition. Addition of MV to human frozen semen has been shown to improve post-thaw motility. Similarly, a beneficial effect has been suggested for frozen equine semen. As post-thaw canine semen quality varies widely between dogs, the aim of our study was to test for the effect of addition of canine MV on post-thaw semen quality in dogs. Semen samples from 10 male dogs were purified from MV and prepared for freezing. In experime...
Revington M.Eight hundred and sixteen blood samples were collected from horses at Sydney race tracks, 1 to 3 h before racing, and subjected to haematological analysis. Haemograms were also performed on 65 blood samples taken from horses at rest in their stalls. These were used as reference values of prerace and resting haemograms, respectively. The haemograms of 29 of the resting horses were compared with the haemograms of the same 29 horses the following day at the race track. Both samples were considered to be representative of their reference populations. In general, there was a significant increase fr...
Lagares MA, Martins HS, Carvalho IA, Oliveira CA, Souza MR, Penna CF, Cruz BC, Stahlberg R, Henry MR.Extenders with a defined composition containing only components with clearly protective effects on sperm during storage would be an advantage. The aims of the present work were to assess whether caseinate, improves cooled and frozen equine semen quality. Semen from six stallions were suspended with four different cooling extenders C1) Kenney extender; C2) 0.6 % caseinate; C3) 2.7 % caseinate ; and C4) C1 + 2.1 % caseinate, and frozen extenders: F1) INRA 82 extender; F2) 1.35 % caseinate; and F3) 2.7 % caseinate. Although there was no significant difference between the motility rate among the c...
Cavalcanti TP, Pereira AG, Bezerra LGP, Moreira SSJ, da Silva AM, Matos YG, Jorge-Neto PN, Silva AR.The use of assisted reproductive techniques, such as chilled semen, contributes to the maintenance and genetic improvement of canine breeding. The INRA-96 extender is a commercially available, chemically defined medium that was initially developed for the preservation of equine semen and exhibits preservation potential in the canine species. This research aims to evaluate the INRA-96 extender as an alternative for the short-term preservation of canine semen in terms of sperm quality parameters such as motility and kinetic parameters, integrity and functionality of the plasma membrane in fresh ...
Du J, Eddington N.A sensitive and selective HPLC method for the determination of the disaccharides of chondroitin sulfate in horse and dog plasma was validated. Chondroitin sulfate is degraded by chondroitinase ABC to three primary unsaturated disaccharides, (1) 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-D-galactose, (2) 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose, and (3) 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose, when treated with chondroitinase. Plasma samples (0.5 ml) were treated with 50 mU of chon...
Delatour P, Garnier F, Maire R.After administration of the racemic drug, the stereoselective quantification of the enantiomers of free and conjugated carprofen was performed in human plasma and in plasma, urine and bile of dogs and horses. In humans, the plasma profile of free carprofen and its glucuronides is not stereoselective and the glucuronides excreted in urine are close to a racemate. In dogs and horses on the contrary, the R(-) enantiomer of the free drug is predominant in plasma, while urine and/or bile concentrations of the glucuronides are high in comparison to plasma with a strong selectivity for the S(+) enant...
McConnico RS, Stokes AM, Eades SC, Moore RM.To examine the secretory response (in the presence and absence of prostaglandin inhibition) in vitro and structural alterations of colonic mucosa in horses after intragastric administration of black walnut extract (BWE). Methods: 14 adult horses. Methods: Seven horses were administered BWE intragastrically and monitored for 11 hours. Tissue samples were obtained from the right ventral, left ventral, and right dorsal colons (RVC, LVC, and RDC, respectively) of the 7 BWE-treated and 7 control horses. Tissue samples were examined via light microscopy, and the extent of hemorrhage, edema, and gran...
Riley CB, McClure JT, Low-Ying S, Dolenko BK, Somorjai RL, Shaw RA.To assess the feasibility of a serum-based test using infrared spectroscopy to identify a subpopulation of mares at risk of producing foals susceptible to failure of passive transfer of immunity (FPT) because of mare-associated factors. Methods: Serum was collected from post-parturient mares (n = 126) and their foals at 24-72 h of age. A radial immunodiffusion IgG test was used to determine each foal's serum IgG concentration. Infrared absorbance spectra of dam sera were collected in the wave number range of 400-4000 cm(-1). Following data preprocessing, pattern recognition techniques were use...
García EDA, Khusro A, Pacheco EBF, Adegbeye MJ, Barbabosa-Pliego A, Lagunas BC, Salas JMC, Mateos RG, Aarti C, Elghandour MMMY.The present context was designed to investigate the efficacy of devil fish (DF; Plecostomus sp.) silage and Staphylococcus saprophyticus on fermentation characteristics as well as greenhouse gases production mitigation attributes in horses. Four levels of ensiled DF at 0 (control DF0), 6 (DF6), 12 (DF12), and 18 (DF18) % were added into the diet. Moreover, three doses of S. saprophyticus (0, 1, and 3 mL/g dry matter [DM]) were used for in vitro fecal fermentation. The use of ensiled DF resulted in increased (P < .0001) pH during fermentation. The asymptotic gas production was the highest (P...
Liu M, Lei B.The secreted Mac protein made by group A Streptococcus (GAS) inhibits opsonophagocytosis of GAS by human polymorphonuclear leukocytes (PMNs). This protein also has the endopeptidase activity against human immunoglobulin G (IgG), and the Cys94, His262 and Asp284 are critical for the enzymatic activity. The horse pathogen Streptococcus equi subspecies equi produces a homologue of Mac (SeMac). SeMac was characterized to determine whether SeMac has IgG endopeptidase activity and inhibits opsonophagocytosis of S. equi by horse PMNs. The gene was cloned and recombinant SeMac was overexpressed in Esc...
Pinaud MA, Roser JF, Dybdal N.In vitro responsiveness of the horse anterior pituitary (AP) gonadotropes to single and multiple GnRH challenges was examined. The pituitaries were collected from reproductively sound mares in estrus (n = 5) and diestrus (n = 5). Uniform 0.5 mm AP slices were subdivided using a 3 mm biopsy punch and then bisected for use in the perifusion chamber. Four bisected sections per chamber were perifused at 0.5 ml/min at 37 C for 560 min in Medium 199 saturated with 95% 0(2)/5% CO2. Ten minute fractions were collected after an initial 2 hr equilibration period. Four different treatment regimes of GnRH...
Webb TL, Burnett RC, Avery AC, Olver CS.Characterization of anemia in horses presents a challenge, as they do not release reticulocytes into peripheral blood. Transferrin receptor (TfR) expression is highest on erythroid cells in people and rats, and measurement of a soluble serum form (sTfR) is used to quantify erythropoiesis in these species. We hypothesized that equine TfR (eTfR) expression is similar in quantity and distribution to that in these other species and thus has potential for characterization of the regenerative response in anemic horses. Objective: This study was conducted to clone and sequence the eTfR gene and measu...
Lyster RL.The three aspartic acid residues that form part of the Ca-binding site of mares' milk lysozyme have apparent pK values of 4.9, 4.3 and 4.1. The fluorescence of tryptophan has been used to compare the denaturation of mares' milk lysozyme by guanidinium chloride at various concentrations of Ca with that of hens' egg-white lysozyme (EC 3.2.1.17) and alpha-lactalbumin. Fluorescence revealed an intermediate stage in the denaturation of mares' milk lysozyme. The Ca-free form of mares' milk lysozyme is slightly more stable than that of alpha-lactalbumin, but its interaction with Ca is similar to that...
Goff AK, Sirois J, Pontbriand D.The objective of this study was to clarify the role of oestradiol in luteal function by examining its effect on the oxytocin stimulation of 15-keto-13,14-dihydro-prostaglandin F2 alpha (PGFM) concentrations in cyclic mares. In the first experiment, three groups of mares (4 per group) were given a bolus injection of 17 alpha-oestradiol (1 mg), oestradiol (1 mg) or vehicle on days 7, 9, 11, 13 and 15 of the cycle. Six hours later the mares were challenged with 10 iu oxytocin intravenously and frequent blood samples were taken from 15 min before to 15 min after for measurement of PGFM. Results sh...
Takagi M, Nishimura K, Oguri N, Ohnuma K, Ito K, Takahashi J, Yasuda Y, Miyazawa K, Sato K.The viability of embryos before flushing from donor mares (n = 5) and after transfer to recipient mares (n = 7) was monitored in mare serum by detecting early pregnancy factor (EPF) using the rosette inhibition test (RIT). The EPF activity was measured in donor mares before and after natural mating at natural estrus; after ovulation on Days 2, 5 and 8; and after embryo flushing (Day 8) on Days 8, 9, 10 and 13 after ovulation. The collected embryos were transferred immediately after flushing. The EPF activity in recipient mares were measured on the day of transfer and after embryo transfer on D...
McClure SR, Miles K, Vansickle D, South T.The objective of this study was to evaluate the effects of variable waveform low-intensity ultrasound on the healing of a fracture gap of the fourth metacarpal bone in horses. A randomized, blinded, controlled trial was conducted in eight healthy adult horses. In each horse, a 1-cm osteotomy of the fourth metacarpal bone was created. One randomly selected metacarpal gap was treated daily with a 40-min session of ultrasound and the opposite gap was managed similarly with an inactive transducer. The fourth metacarpal bones were radiographed weekly. Fluorescent markers were administered at 14, 28...
Ducharme NG, Burton JH, van Dreumel AA, Horney FD, Baird JD, Arighi M.The nutritional implications and adaptive processes resulting from resection of 75% of the length of the large colon in ponies were investigated. Ten ponies in good physical condition were divided into two groups: six in the experimental group and four in the control group. During the sixth postoperative month, two digestibility studies were conducted, and phosphate fractional renal excretion and serum biochemical profiles were determined in both groups. The ponies (N = 10) were euthanized six months postoperatively, and gross and histopathological examinations were performed. Results of the s...
Kerrigan LE, Thompson DL, Chapman AM, Oberhaus EL.Sympathoadrenal stimulation may perturb results of endocrine tests performed on fractious horses. Sedation may be beneficial; however, perturbation of results may preclude useful information. Four experiments were designed to 1) determine the effects of epinephrine on insulin response to glucose (IR2G), 2) assess the effects of detomidine (DET), alone or combined with butorphanol (DET/BUT), on IR2G and glucose response to insulin (GR2I), and 3) assess the effects of BUT alone on IR2G. In Experiment 1, mares were administered saline or epinephrine (5 μg/kg BW) immediately before infusion of gl...
Ortiz I, Quiñones-Pérez C, Hidalgo M, Consuegra C, Diaz-Jimenez M, Dorado J, Vega-Pla JL, Crespo F.Dynamic assessment of sperm DNA fragmentation (SDF) has shown to give fuller understanding of stallion semen quality; however, there have been limited attempts to use this parameter to investigate seasonal changes in productive functions. The aims of this study were to: (a) establish a reliable mathematical model to describe the longevity of cooled-stored sperm DNA integrity; (b) to examine the effect of seasonal variations on SDF. Ejaculates were cooled to 5°C, and SDF was analysed after 0, 6 and 24 hr of storage. The coefficient of determination (R ) was calculated after fine-tuning linear...
Semotok CA, Johnson WH, LaMarre J, Gentry PA.This study was designed to evaluate the amounts of coagulation factors and to determine whether the protein profile in pre-ovulatory ovarian follicular fluid aspirated from ovaries collected from mares at slaughter are representative of that in follicular fluid collected from live animals. The proteins evaluated included, (i) albumin, ceruloplasmin and fibronectin, (ii) the procoagulant plasma proteins, Factor V (FV), Factor VII (FVII), Factor X (FX) and prothrombin, and (iii) the anticoagulant plasma proteins, antithrombin and alpha2-macroglobulin. The amounts of the individual proteins were ...
Knych HK, Steinmetz SJ, McKemie DS.The anti-anxiety and calming effects following activation of the GABA receptor have been exploited in performance horses by administering products containing GABA. The primary goal of the study reported here was to describe endogenous concentrations of GABA in horses and the pharmacokinetics, selected pharmacodynamic effects, and CSF concentrations following administration of a GABA-containing product. The mean (±SD) endogenous GABA level was 36.4 ± 12.5 ng/mL (n = 147). Sixteen of these horses received a single intravenous and oral dose of GABA (1650 mg). Blood, urine, and cerebrospin...
Yamamoto Y, Iwafune K, Chûjô R, Inoue Y, Imai K, Suzuki T.1H-NMR spectra of deoxy myoglobins (Mbs) from shark (Galeorhinus japonicus), horse, and sperm whale have been studied to gain insights into their active site structure. It has been demonstrated for the first time that nuclear Overhauser effect (NOE) can be observed between heme peripheral side-chain proton resonances of these paramagnetic complexes. Val-E11 methyl and His-F8 C delta H proton resonances of these Mbs were also assigned from the characteristic shift and line width. The hyperfine shift of the former resonance was used to calculate the magnetic anisotropy of the protein. The shift ...
Chottard G, Michelon M, Hervé M, Hervé G.Complex formation between horse heart ferricytochrome c and large three-dimensional polyanions has been investigated, in order to study the influence of surface electrostatic interactions on the structural and redox properties of cytochrome c. Cytochrome c binds the large heteropolytungstates (NaSb9W21O86)18- and (KAs4W40O140)27- with a 1/1 polyanion/cytochrome c ratio, and the smaller ion (SiW11O39)8- with a 2/1 ratio. Upon complexation, cytochrome c undergoes structural changes that are dependent on the size and charge of the polyanion, and on the pH and ionic strength of the medium. Three d...
Walters B, Trumble TN, Wendt-Hornickle E, Kennedy M, Guedes A.Apoptosis is an important mechanism underlying chondrocyte loss in osteoarthritis that could be affected by modulation of lipid signaling via inhibition of cyclooxygenases (COX) and soluble epoxide hydrolase (sEH). Objective: To determine the impact of inhibiting COX and sEH alone or in combination on apoptosis of equine chondrocytes. Methods: Cultured primary equine chondrocytes were subjected to serum deprivation or incubation with 1 μg/ml tunicamycin for 24 h to induce apoptosis via caspase activation and endoplasmic reticulum (ER) stress, respectively. Cells were treated with the non-se...
