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.
Legacki EL, Corbin CJ, Ball BA, Scoggin KE, Stanley SD, Conley AJ.Steroidogenic enzymes in placentas shape steroid hormone profiles in the maternal circulation of each mammalian species. These include 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase (3βHSD) and 17α-hydroxylase/17,20-lyase cytochrome P450 (P450c17) crucial for progesterone and androgen synthesis, respectively, as well as aromatase cytochrome P450 (P450arom) that converts Δ4-androgens to estrogens. 5α-reductase is another important enzyme in equine placentas because 5α-dihydroprogesterone (DHP) sustains pregnancy in the absence of progesterone in the second half of equine pregnancy. DHP a...
Hopster K, Ambrisko TD, Kästner SBR.To compare the lithium dilution method for cardiac output (LiDCO) and bolus-thermo-dilution (BTD) measurements before and during infusion of dobutamine, dopamine, phenylephrine, or noradrenaline at 2 different doses in anesthetized horses and to examine the correlation between sensor voltages (saline-blood exposed) and possible measurement errors. Methods: Prospective experimental study. Methods: University teaching hospital. Methods: Nine Warmblood horses. Methods: Following 90 minutes of equilibration, 3 different doses of dobutamine (0.5-3 μg/kg/min), dopamine (1-5 μg/kg/min), phenylephri...
Textor JA, Clark KC, Walker NJ, Aristizobal FA, Kol A, LeJeune SS, Bledsoe A, Davidyan A, Gray SN, Bohannon-Worsley LK, Woolard KD, Borjesson DL.Distal extremity wounds are a significant clinical problem in horses and humans and may benefit from mesenchymal stem cell (MSC) therapy. This study evaluated the effects of direct wound treatment with allogeneic stem cells, in terms of gross, histologic, and transcriptional features of healing. Three full-thickness cutaneous wounds were created on each distal forelimb in six healthy horses, for a total of six wounds per horse. Umbilical cord-blood derived equine MSCs were applied to each wound 1 day after wound creation, in one of four forms: (a) normoxic- or (b) hypoxic-preconditioned cells ...
Siwinska N, Zak A, Baron M, Cylna M, Borowicz H.The aim of this study was to determine the normal location, wall thickness and motility of the right dorsal colon in adult ponies and miniature horses. The abdominal ultrasonography examination was performed in a study group consisting of 23 ponies and miniature horses and in a control group comprising ten Thoroughbred horses. The procedure was performed in unsedated standing animals. The location and the thickness of the right dorsal colonic wall was examined on the right side of the abdomen between the 10th and the 14th intercostal space. The contractility was recorded in the 12th intercosta...
Bonilla-Correal S, Noto F, Garcia-Bonavila E, Rodríguez-Gil JE, Yeste M, Miro J.Aquaporins (AQPs) are transmembrane proteins found in all cells and are responsible for the transport of water and small solutes. While these proteins have been found in the spermatozoa of humans, rodents, pigs and cattle, where not only do they play a role for the regulation of sperm volume but are also related with the sperm resilience to withstand freeze-thawing procedures, their presence in stallion sperm is yet to be reported. Therefore, the objectives of this work were as follows: (i) to determine whether AQP3, AQP7 and AQP11 are present in stallion sperm and (ii) to investigate whether ...
Miyata H, Itoh R, Sato F, Takebe N, Hada T, Tozaki T.Variants of the Myostatin gene have been shown to have an influence on muscle hypertrophy phenotypes in a wide range of mammalian species. Recently, a Thoroughbred horse with a C-Allele at the g.66493737C/T single-nucleotide polymorphism (SNP) has been reported to be suited to short-distance racing. In this study, we examined the effect of the Myostatin SNP on muscle fiber properties in young Thoroughbred horses during a training period. To investigate the effect of the Myostatin SNP on muscle fiber before training, several mRNA expressions were relatively quantified in biopsy samples from the...
Pereira RCDF, De La Côrte FD, Brass KE, da Silva Azevedo M, Gallio M, Cantarelli C, Dau SL, Cezar AS, Inkelmann MA.Wounds localized on the distal limbs in horses are difficulty healing. No studies have been conducted to evaluate homologous platelet-rich plasma (PRP) in horses. The aim of this study was to evaluate the effect upon applying autologous PRP, homologous PRP, and autologous PRP gel on the wound healing process of wounds on the distal limb of horses. To study a possible correlation between the platelet count and wound healing time, four skin wounds of 4 cm2 were surgically created on the dorsolateral aspect of the third metacarpus in eight healthy adult horses. Each skin wound was randomly treate...
Lee JY, Na HJ, Kim HM, Lee SC, Lee JY, Chung CP, Seol YJ, Park YJ.The purpose of this study was to evaluate the efficacy and safety of equine-derived bone matrix as a carrier for recombinant human platelet-derived growth factor BB (rhPDGF-BB) versus beta-tricalcium phosphate (β-TCP) for the treatment of intraosseous periodontal defects in adult patients. This study was performed on 32 adults with advanced periodontal disease. Eligible subjects were randomized in 1:1 ratio into a test (rhPDGF-BB-coated equine-derived bone matrix) or control group (rhPDGF-BB-coated β-TCP). Probing pocket depth (PD), clinical attachment level (CAL), gingival recession (GR), a...
Thu VT, Kim HK, Han J.Numerous animal cardiac exercise models using animal subjects have been established to uncover the cardiovascular physiological mechanism of exercise or to determine the effects of exercise on cardiovascular health and disease. In most cases, animal-based cardiovascular exercise modalities include treadmill running, swimming, and voluntary wheel running with a series of intensities, times, and durations. Those used animals include small rodents (e.g., mice and rats) and large animals (e.g., rabbits, dogs, goats, sheep, pigs, and horses). Depending on the research goal, each experimental protoc...
White SH, Wohlgemuth S, Li C, Warren LK.Exercise is known to promote mitochondrial biogenesis in skeletal muscle as well as enhance mitochondrial function and efficiency in human and rodent models. These adaptations help to decrease exercise-associated production of reactive oxygen species, which can negatively affect health and performance if antioxidant mechanisms are overwhelmed. Little is known about the adaptations of mitochondria in response to exercise training in the growing horse or if supplementation with a dietary antioxidant can improve mitochondrial function. To evaluate the separate and combined effects of selenium (Se...
Jäderkvist Fegraeus K, Hirschberg I, Árnason T, Andersson L, Velie BD, Andersson LS, Lindgren G.The Icelandic horse is a breed known mainly for its ability to perform the ambling four-beat gait 'tölt' and the lateral two-beat gait pace. The natural ability of the breed to perform these alternative gaits is highly desired by breeders. Therefore, the discovery that a nonsense mutation (C>A) in the DMRT3 gene was the main genetic factor for horses' ability to perform gaits in addition to walk, trot and canter was of great interest. Although several studies have demonstrated that homozygosity for the DMRT3 mutation is important for the ability to pace, only about 70% of the homozygous mutan...
Holcomb KE.Shade or shelter as protection from extremes of weather is required for horses at agricultural research and teaching facilities and is recommended or required by many states, professional organizations, and industry groups. The focus of this paper is the recent research on the responses of horses to hot, sunny weather, which has begun to provide scientific evidence that characterizes how and when shade is used and any benefits shade confers on horses. These behavioral and physiological findings support provision of shade as a resource for thermal comfort and the expression of normal behavior t...
Wynn MAA, Esteller-Vico A, Legacki EL, Conley AJ, Loux SC, Stanley SD, Curry TE, Squires EL, Troedsson MH, Ball BA.During the latter half of gestation in mares, there is a complex milieu of pregnanes in peripheral blood. Progesterone concentrations are often assessed by immunoassay during late gestation as a measure of pregnancy well-being; however, interpretation of results is complicated by the numerous cross-reacting pregnanes present in high concentrations during late gestation. Further, many mares are supplemented with an exogenous progestin, altrenogest, which may also cross-react with existing assays and further confound interpretation. The objectives of this study were: 1) to compare differences in...
Cabezas J, Rojas D, Navarrete F, Ortiz R, Rivera G, Saravia F, Rodriguez-Alvarez L, Castro FO.Adult stromal mesenchymal stem cells (MSCs) have been postulated as responsible for cell renewal in highly and continuously regenerative tissues such as the endometrium. MSCs have been identified in the endometrium of many species including humans, rodents, pets and some farm animals, but not in horses. The objective of this work was to isolate such cells from the endometrium of mares and to compare their main biological attributes with horse adipose-derived MSCs. Here we successfully isolated and characterized endometrial MSCs (eMSCs) from mares. Said cells showed fibroblast-like morphology, ...
Carossino M, Wagner B, Loynachan AT, Cook RF, Canisso IF, Chelvarajan L, Edwards CL, Nam B, Timoney JF, Timoney PJ, Balasuriya UBR.Equine arteritis virus (EAV) has the ability to establish persistent infection in the reproductive tract of the stallion (carrier) and is continuously shed in its semen. We have recently demonstrated that EAV persists within stromal cells and a subset of lymphocytes in the stallion accessory sex glands in the presence of a significant local inflammatory response. In the present study, we demonstrated that EAV elicits a mucosal antibody response in the reproductive tract during persistent infection with homing of plasma cells into accessory sex glands. The EAV-specific immunoglobulin isotypes i...
Joonè CJ, Schulman ML, Fosgate GT, Claes ANJ, Gupta SK, Botha AE, Human A, Bertschinger HJ.Circulating anti-Müllerian hormone concentration (AMH) is positively correlated to the number of small growing follicles in the mare and may reflect ovarian function. Dynamics of AMH during immunocontraception have not previously been investigated. This study aimed to compare serum AMH in mares following treatment with native porcine zona pellucida (pZP), recombinant pZP3 and pZP4 (reZP) or gonadotrophin releasing hormone (GnRH) vaccines, and saline-treated controls. Stored sera collected during two previous studies examining ovarian activity in mares during zona pellucida (ZP) or GnRH immuno...
Ghallab AM, Shahat AM, Fadl AM, Ayoub MM, Moawad AR.The aim of the present study was to evaluate the effects of supplementation of semen extender with various non-enzymatic antioxidants on the quality of cooled or cryopreserved Arabian stallion spermatozoa. Semen collected from four pure Arabian stallions was centrifuged at 600g for 15 min. Spermatozoa were then diluted in INRA-82 extender supplemented with bovine serum albumin (BSA; 0, 10, 15 and 20 mg/mL) or trehalose (0, 75, 100 and 150 mM) or zinc sulphate (0, 100, 150 and 200 μM). The diluted semen was then either cooled at 5 °C or cryopreserved in 0.5-ml plastic straws. After cooli...
Gilger BC.This article reviews the literature for studies describing advanced imaging of the equine eye as a reference for practitioners to help in the selection of image modalities, describe how to use the instruments, and help interpret the image findings. Indications for, technique of, and image interpretation of advanced image modalities such as ultrasound, computed tomography, MRI, optical coherence tomography, confocal microscopy, and angiography are reviewed. The article is organized anatomically, not by instrument, so that the reader will be able to quickly research ways to image specific diseas...
Martin EM, Jones SL.Inhibition of prostaglandin E2 (PGE2) production effectively limits inflammation in horses, however nonspecific prostaglandin blockade via cyclooxygenase (COX) inhibition elicits deleterious gastrointestinal side effects in equine patients. Thus, more selective PGE2 targeting therapeutics are needed to treat inflammatory disease in horses. One potential target is microsomal prostaglandin E-synthase-1 (mPGES-1), which is the terminal enzyme downstream of COX-2 in the inducible PGE2 synthesis cascade. This enzyme has yet to be studied in equine leukocytes, which play a pivotal role in equine inf...
Ortega Ferrusola C, Anel-López L, Ortiz-Rodriguez JM, Martin Muñoz P, Alvarez M, de Paz P, Masot J, Redondo E, Balao da Silva C, Morrell JM....In order to gain insight of the modifications that freezing and thawing cause to the surviving population of spermatozoa, changes in the potential of the plasma membrane (Em) and intracellular Na content of stallion spermatozoa were investigated using flow cytometry. Moreover, caspase 3 activity was also investigated and the functionality of the Na -K ATPase pump was investigated before and after freezing and thawing. Cryopreservation caused a significant (p < 0.001) increase in the subpopulation of spermatozoa with depolarized sperm membranes, concomitantly with an increase (p < 0.0...
Migdał A, Migdał Ł, Zagrajczuk A, Kochan J, Nowak A, Okólski A.The aim of this study was to determine the effect of increased levels of prolactin (PRL) on the concentration of immunoglobulins in the blood, colostrum and milk of mares. The study was conducted on 12 mares of the Polish Pony breed (6 in the control and 6 in the experimental group). To induce hyperprolactinaemia in mares of the experimental group, 750 mg sulpiride was administered orally once a day. The initial PRL concentration was 52.22 ± 11.21 ng/ml in the control group and 49.39 ± 10.12 ng/ml in the experimental group. In the subsequent days, the concentration of PRL dynamically changed...
Li B, He X, Zhao Y, Bai D, Shiraigo W, Zhao Q, Manglai D.Studies on the molecular genetics of horse skin pigmentation have typically focused on very few genes and proteins. In this study, we used Illumina sequencing to determine the global gene expression profiles in horses with white-colored coats and those with black-colored coats, with the goal of identifying novel genes that could regulate horse coat color. Results: Genes encoding ribosomal-associated proteins were highly expressed in horse skin. We found a total of 231 unigenes that were differentially expressed between horses with white coats and horses with black coats; 119 were down-regulate...
Martin EM, Till RL, Sheats MK, Jones SL.In many equine inflammatory disease states, neutrophil activities, such as adhesion, migration, and reactive oxygen species (ROS) production become dysregulated. Dysregulated neutrophil activation causes tissue damage in horses with asthma, colitis, laminitis, and gastric glandular disease. Non-steroidal anti-inflammatory drugs do not adequately inhibit neutrophil inflammatory functions and can lead to dangerous adverse effects. Therefore, novel therapies that target mechanisms of neutrophil-mediated tissue damage are needed. One potential neutrophil-targeting therapeutic is the PGE1 analog, m...
Gomes RG, Silva CB, González SM, Oliveira RL, Max MC, Lisboa LA, Barreiros TRR, Santos MM, Sarapião FD, Gastal EL, Seneda MM.The effect of different concentrations of alpha lipoic acid (ALA) on the development and morphology of preantral follicles, as well as the proliferative activity of granulosa cells, was assessed after short-term culture. Ovaries (n = 5) of five seasonal anestrous mares were harvested in a local abattoir. At the laboratory, nine ovarian fragments (5 × 5 × 1 mm) from each animal were used. One fragment was immediately fixed in Bouin and subjected to histological and immunohistochemistry (proliferating cell nuclear antigen, PCNA) analyses (noncultured group; D0 = day 0). The other eigh...
Jezierski T, Jaworski Z, Sobczyńska M, Ensminger J, Górecka-Bruzda A.The aim of the study was to assess whether adult stallions differentiate their olfactory and marking behaviour towards the excreta of their potential male rivals and mares. Four Konik polski stallions were individually exposed simultaneously to their own and each others' faeces as well as faeces of mares in oestrus vs. dioestrus. Five series of 30min observation sessions were conducted in a round pen each on two consecutive days from March to July, totaling in 5h observation per stallion. Stallions sniffed and displayed flehmen reaction towards mares' faeces significantly longer (P<0.01) th...
Hall SE, Upton RMO, McLaughlin EA, Sutherland JM.The mare ovary is unique in its anatomical structure; however, the signalling pathways responsible for physiological processes, such as follicular activation, remain uncharacterised. This provided us with the impetus to explore whether signalling molecules from important folliculogenesis pathways, phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) and Janus kinase/signal transducer and activator of transcription (JAK/STAT), are conserved in the mare ovary. Messenger RNA expression of six genes important in follicle development was measured using quantitative polymerase chain reaction and pr...
Leisinger CA, Medina V, Markle ML, Paccamonti DL, Pinto CRF.A novel in vivo model utilizing serial administrations of PGF2α to induce aluteal cycles in the mare was used to evaluate the effects of progesterone-deprivation on the morphology of in vivo preimplantation embryos. We hypothesized that equine embryos produced during induced aluteal cycles (AL) would be developmentally affected, characterized by earlier embryo stage at collection, smaller embryo diameter, and lower quality grade, compared with those collected on the same day post-ovulation from control cycles during diestrus (high progesterone; > 4 ng/mL). Seven cyclic mares with a median ...
Raeside JI.The role of steroids in human medicine is well recognized, but the major contributions made by the large domestic animals as a source of material in the discovery, isolation, and determination of the structure of the steroid hormones is less well appreciated. After a brief reminder of the early efforts to obtain a reliable source of steroids for clinical use, the narrative here is to outline one example where success was ultimately achieved for estrogen replacement therapy. Whereas knowledge of the high concentrations of estrogens in urine of pregnant women and mares dates from the late 1920s,...
Peters J, Block W, Oswald S, Freyer J, Grube M, Kroemer HK, Lämmer M, Lütjohann D, Venner M, Siegmund W.The delivery of clarithromycin (CRL) to its site of action in bronchial/alveolar epithelial cells (EC), bronchial epithelial lining fluid (ELF), and bronchoalveolar lavage cells (BALC) may be influenced by CYP3A4 and the drug transporters, ATP-binding cassette (ABC) B1 and ABCC2 and organic anion-transporting polypeptides (OATPs), which can be modulated and/or up-regulated via the nuclear pregnane X receptor (PXR) by rifampicin (RIF). Therefore, we evaluated the disposition and pulmonary distribution of CLR (7.5 mg/kg b.i.d., 21 days) and expression of ABCB1, ABCC2, OATP1A2, and OATP2B1 in EC ...
Ali OJ, Comerford EJ, Clegg PD, Canty-Laird EG.BiTendons are constructed from collagenous fascicles separated by endotenon/interfascicular matrix (IFM). Tendons may be specialised for precision movement or to store energy during locomotion and for the latter the elasticity of the endotenon/IFM is particularly important. The equine superficial digital flexor tendon (SDFT) is a dedicated energy-storing tendon with a similar function to the human Achilles tendon. Classical anatomical descriptions portray fascicles as longitudinally arranged distinct anatomical structures. In the present study, using three-dimensional reconstruction from whole...
Reilas T, Rivera Del Alamo MM, Liepina E, Yeste M, Katila T.Cervical patency is considered to be important for uterine drainage after mating or artificial insemination (AI), and failure to relax or premature tightening of the cervix can lead to persistent endometritis. This study investigated the hypothesis that cervical occlusion after AI increases accumulation of fluid, polymorphonuclear leukocytes (PMNs), and cytokines in the uterine lumen. Endometrial swabs were obtained from 29 normal cyclic mares during the first, third, and fifth estrus and biopsies during the first and fifth estrus. All mares were inseminated during the second and fourth estrus...
Lester GD, Merritt AM, Kuck HV, Burrow JA.Intravenous (IV) and intragastric (IG) administration of fluid therapy are commonly used in equine practice, but there are limited data on the systemic, renal, and enteric effects. Objective: IV fluid administration will increase intestinal and fecal hydration in a rate-dependent manner after hypertonic dehydration, but will be associated with significant urinary water and electrolyte loss. Equivalent volumes of IG plain water will result in comparatively greater intestinal hydration with less renal loss. Methods: Six Thoroughbred geldings. Methods: Experimental study. 6 by 6 Latin square desi...
Ball BA, Vo A.Osmotic stress attributed to differences in the relative permeability of cryoprotectants, such as glycerol and water, appears to be an important factor in cryodamage. The objective of this study was to characterize the osmotic tolerance of equine spermatozoa, and to evaluate the effects of addition and removal of cryoprotectants from equine spermatozoa on their motility, and membrane and acrosomal integrity, as well as their mitochondrial membrane potential. Equine spermatozoa had a limited osmotic tolerance to anisosmotic conditions. Although the addition of increasing concentrations of glyce...
Pozor M, Morrissey H, Albanese V, Khouzam N, Deriberprey A, Macpherson ML, Kelleman AA.The goal of this study was to investigate correlations between objective measures of testicular echotexture and histomorphometric attributes related to the histological composition of stallion testes. Fifty-four scrotal testes were obtained from three groups of stallions during routine castrations: colts <1 yr old (n = 18), young stallions 1-5 yrs old (n = 27), mature stallions > 5 yrs old (n = 9). In addition, two scrotal testes with degeneration, 16 retained inguinal and 10 retained abdominal testes were surgically obtained. Cross-sectional and longitudinal ultrasonograms were obt...
Gérard N, Robin E.Terminal follicular differentiation and ovulation are essential steps of reproduction. They are induced by the increase in circulating LH, and lead to the expulsion from the ovary of oocytes ready to be fertilized. This review summarizes our current understanding of cellular and molecular pathways that control ovulation using a broad mammalian literature, with a specific focus to the mare, which is unique in some aspects of ovarian function in some cases. Essential steps and key factors are approached. The first part of this review concerns LH, receptors and signaling, addressing the descripti...
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...
Murcia-Robayo RY, Jouanisson E, Beauchamp G, Diaw M.Evaluation of sperm morphology is part of the assessment of fertility in human and animal reproduction. Analyses can be performed using different techniques, including the use of staining methods In our prospective study, the morphology of equine sperm was evaluated using 3 staining methods Diff-Quik, eosin-nigrosin, and SpermBlue, the latter being a relatively new stain commonly used for human sperm. Our hypotheses were that (1) SpermBlue allows easier assessment of horse sperm morphology and facilitates better identification of sperm abnormalities, and (2) sperm morphology classification dif...
Sipahutar H, Sourdaine P, Moslemi S, Plainfossé B, Séralini GE.High levels of plasma estrogens constitute an endocrine peculiarity of the adult stallion. This is mostly due to testicular cytochrome p450 aromatase, the only irreversible enzyme responsible for the bioconversion of androgens into estrogens. To identify more precisely the testicular aromatase synthesis sites in the stallion, testes from nine horses (2-5 years) were obtained during winter or spring. Paraplast-embedded sections were processed using rabbit anti-equine aromatase, followed by biotinylated goat anti-rabbit antibodies, and amplified with a streptavidin-peroxidase complex. Immunoreac...
Turkstra JA, van der Meer FJ, Knaap J, Rottier PJ, Teerds KJ, Colenbrander B, Meloen RH.Immunization against gonadotrophin releasing hormone (GnRH) was studied as an alternative for the commonly used surgical castration in stallions. Two GnRH vaccines comprising non-mineral oil adjuvants were evaluated for their potential to induce high antibody titers directed against GnRH and subsequent effects on reproductive characteristics. Twelve sexually mature male hemicastrated Shetland ponies were assigned to three groups. Group 1 and 2 were injected with 1mg peptide equivalent of G6k-GnRH-tandem-dimer conjugated to ovalbumin (OVA) in CoVaccine HT adjuvant (GnRH/CoVaccine) and in Carbop...
Kirschvink N, Smith N, Fiévez L, Bougnet V, Art T, Degand G, Marlin D, Roberts C, Génicot B, Lindsey P, Lekeux P.In heaves-affected horses the relation between oxidant status, airway inflammation (AI) and pulmonary function (PF) is unknown. The oxidant status of blood and pulmonary epithelial lining fluid (PELF) of healthy (H, n = 6) and heaves-affected horses in clinical remission (REM, n = 6) and in crisis (CR, n = 7) was assessed at rest, during and after standardised exercise test by measurement of reduced and oxidised glutathione, glutathione redox ratio [GRR%]; uric acid and 8-epi-PGF2alpha. Oxidant status was related to PF parameters (mechanics of breathing and arterial blood gas tension) and Al p...
Grange S, Duncan P, Gaillard JM.We investigated density dependence on the demographic parameters of a population of Camargue horses (Equus caballus), individually monitored and unmanaged for eight years. We also analysed the contributions of individual demographic parameters to changes in the population growth rates. The decrease in resources caused a loss of body condition. Adult male survival was not affected, but the survival of foals and adult females decreased with increasing density. Prime-aged females maintained high reproductive performance at high density, and their survival decreased. The higher survival of adult m...
Budsuren U, Ulaangerel T, Shen Y, Liu G, Davshilt T, Yi M, Bold D, Zhang X, Bai D, Dorjgotov D, Davaakhuu G, Jambal T, Li B, Du M, Dugarjav M, Bou G.Myostatin (MSTN), a member of the transforming growth factor-β superfamily, inhibits the activation of muscle satellite cells. However, the role and regulatory network of MSTN in equine muscle cells are not well understood yet. We discovered that MSTN knockdown significantly reduces the proliferation rate of equine muscle satellite cells. In addition, after the RNA sequencing of equine satellite cells transfected with MSTN-interference plasmid and control plasmid, an analysis of the differentially expressed genes was carried out. It was revealed that MSTN regulatory networks mainly involve ge...
Cowley AB, Lukat-Rodgers GS, Rodgers KR, Benson DR.N-Acetylmicroperoxidase-8 (1) contains heme and residues 14-21 of horse mitochondrial cytochrome c (cyt c). The two thioether bonds linking protein to heme in cyt c are present in 1, and the native axial ligand His-18 remains coordinated to iron. As an approach to probing structural or functional roles played by the double covalent heme-protein linkage in cyt c, we have initiated a study in which the properties of 1 are compared with those of a synthetic mono-His coordinated heme peptide containing a single covalent linkage (2). One consequence of the greater conformational restriction imposed...
Santibáñez R, Lara F, Barros TM, Mardones E, Cuadra F, Thomson P.The ocular microbiome in horses is poorly described compared to other species, and most of the information available in the literature is based on traditional techniques, which has limited the depth of the knowledge on the subject. The objective of this study was to characterize and predict the metabolic pathways of the ocular microbiome of a group of healthy horses. Conjunctival swabs were obtained from both eyes of 14 horses, and DNA extraction was performed from the swabs, followed by next generation sequencing and bioinformatics analyses employing DADA2 and PICRUSt2. A total of 17 phyla we...
Fazio E, Medica P, Cravana C, Bruschetta G, Ferlazzo A.The purpose of this study was to determine which physiological seasonal thyroid and lipid panel (triglyceride, [TG], total cholesterol, [tCho], high-density lipoprotein cholesterol, [HDL Cho], LDL cholesterol, phospholipids, [PDs]) changes occur in 12 Thoroughbred pregnant and six nonpregnant mares over a period of 12 months, from April to March, by into account the lactation stage. Serum total triiodothyronine (T3) and thyroxine (T4) levels were measured using immunoenzymatic assay kits; the serum lipid panel was analyzed using the enzymatic colorimetric method. One-way ANOVA reported a sign...
Tiralongo J, Schmid H, Thun R, Iwersen M, Schauer R.Microsomes prepared from equine submandibular glands and incubated with tritium-labelled AcCoA incorporated acid-insoluble radioactivity in a manner dependent on time, protein, membrane integrity and AcCoA concentration, with incorporation being optimal at 37 degrees C and pH 6.6. Under the experimental conditions used a K(M) of 32.1 microM for AcCoA and a V(max) of 1.2 pmol/mg protein x min was obtained. The incorporation of acid-insoluble radioactivity was also inhibited by CoA in a competitive manner (K(i)=240 microM), as well as by para-chloromercuribenzoate, 3'-dephospho-CoA, 5'-IDP, 5'-A...
Figueiredo JP, Muir WW, Sams R.To compare the cardiorespiratory, gastrointestinal, analgesic, and behavioral effects between IV and IM administration of morphine in conscious horses with no signs of pain. Methods: 6 healthy adult horses. Methods: Horses received saline (0.9% NaCl) solution (IM or IV) or morphine sulfate (0.05 and 0.1 mg/kg, IM or IV) in a randomized, masked crossover study design. The following variables were measured before and for 360 minutes after drug administration: heart and respiratory rates; systolic, diastolic, and mean arterial blood pressures; rectal temperature; arterial pH and blood gas variabl...
Asano R, Suzuki K, Otsuka T, Otsuka M, Sakurai H.Concentrations of trace elements (As, Al, Pb, Cd, Hg, Se, Si, P, Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Cr, Ni and Mn) in the mane hair obtained from 9 female and 15 male healthy racing Thoroughbred horses aged 2-5 years were analyzed by the inductively coupled plasma atomic emission spectrometry (ICP-AES) method. No significant differences between the female and male horses were observed in the mean concentrations of those minerals. Significantly positive correlations with age were observed in Cd (r=0.546, p<0.01) and Mo (r=0.733, p<0.001). Significantly negative correlations with age were observed i...
de Laat MA, Clement CK, McGowan CM, Sillence MN, Pollitt CC, Lacombe VA.Equine laminitis, a disease of the lamellar structure of the horse's hoof, can be incited by numerous factors that include inflammatory and metabolic aetiologies. However, the role of inflammation in hyperinsulinaemic laminitis has not been adequately defined. Toll-like receptor (TLR) activation results in up-regulation of inflammatory pathways and the release of pro-inflammatory cytokines, including interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α), and may be a pathogenic factor in laminitis. The aim of this study was to determine whether TLR4 expression and subsequent pro-infla...
Warren LK, Lawrence LM, Thompson KN.Because exercise fatigue has been associated with the accumulation of lactic acid, factors that influence lactate metabolism during exercise can potentially enhance performance. The objective of this study was to examine the effects of supplemental betaine on eight mature Thoroughbred horses before and after 8 wk of conditioning. The effects of betaine were tested in two cross-over design experiments, allowing each horse to receive both the control and betaine treatments at each fitness level. Ingestion of 80 mg of betaine/kg of BW for 14 d before exercise testing did not alter plasma lactate,...
Franck T, Kohnen S, Deby-Dupont G, Grulke S, Deby C, Serteyn D.An original method called SIEFED (specific immunological extraction followed by enzymatic detection) was developed for the specific detection of the activity of equine myeloperoxidase (MPO). The method consists of the extraction of MPO from aqueous solutions by immobilized anti-MPO antibodies followed by washing (to eliminate proteins and interfering molecules) and measurement of MPO activity using a detection system containing a fluorogenic substrate, hydrogen peroxide, and nitrite as reaction enhancer. The SIEFED technique was applied to study active MPO in horse biological fluids and the ef...
Hoogewijs M, Morrell J, Van Soom A, Govaere J, Johannisson A, Piepers S, De Schauwer C, De Kruif A, De Vliegher S.The increasing use of modern reproductive techniques in human medicine has led to a higher demand for isolation of motile sperm. Several of these isolation techniques have been adapted for veterinary use and can be applied for the selection of a superior sperm sample from stallion semen. Until recently a major disadvantage of such isolation techniques was the limitation in sperm volume that could be handled. Androcoll-E had been shown to be successful for processing large volumes of equine semen but there are few data to substantiate the potential beneficial effect of freezing an Androcoll-E s...
Adair HS, Marcellin-Little DJ, Levine D.To assess validity and inter- and intra-tester reliability of equine goniometry and to establish values for carpal, metacarpophalangeal, tarsal, and metatarsophalangeal flexion and extension in horses. Methods: Seventeen healthy equine subjects of varied breeds were used. Methods: Three investigators blindly and independently measured in triplicate the extension and flexion of carpal, metacarpophalangeal, tarsal, and metatarsophalangeal joints of 17 horses after sedation. Radiographs of these joints in flexion and extension were acquired while under sedation. Goniometric and radiographic measu...
McGuire TC, Crawford TB.Immunoglobulin A (IgA) was demonstrated in equine serum and secretions. This immunoglobulin had a molecular weight extending from 150,000 to 700,000 and reacted with specific antihuman alpha-chain antiserum. Antigenic determinants specific for secretory IgA were demonstrated and found to be absent on serum IgA. Antigen binding activity was detected in IgA from tears. Purified IgA was antigenically distinct from equine IgG, IgM, IgG(T), and aggregating immunoglobulin. Quantitative studies demonstrated that IgA was the predominant immunoglobulin in tears and milk but not in colostrum. The electr...
Steger DJ, Altschmied J, Büscher M, Mellon PL.Primate and equine species are thought to be unique among mammals in synthesizing placental gonadotropin glycoprotein hormones. Human chorionic gonadotropin (CG) and equine pregnant mare's serum gonadotropin (PMSG) are produced in placenta by the specific activation of a glycoprotein hormone alpha-subunit gene and a corresponding beta-subunit gene. The evolutionary mechanisms for the apparently independent acquisition of tissue specificity were investigated by cloning the 5' flanking region of the equine alpha-subunit gene and comparing the DNA elements and trans-acting factors involved in pla...
Starbuck GR, Stout TA, Lamming GE, Allen WR, Flint AP.Circulating concentrations of 13,14-dihydro-15-ketoprostaglandin F2 alpha (PGFM) were measured before and after administration of oxytocin and after endometrial biopsy, with or without uterine flushing performed per vaginam, on days 10, 14 and 18 after ovulation in nine pregnant and nine cyclic mares. Concentrations of oxytocin receptor were measured in endometrial biopsy samples. Neither pregnancy status nor time after ovulation affected basal PGFM concentrations. PGFM concentrations were increased after oxytocin administration on each of the days studied in cyclic mares; on day 14 the mean r...
Moens Y, Lagerweij E, Gootjes P, Poortman J.The distribution of inspired gas to each lung, time constants of the lungs and parameters of gas exchange were studied in 2 groups of horses (mean bwt 606 kg), anaesthetised using thiopentone and chloral hydrate and breathing room air. One group (n = 4) had a downward curved abdominal contour (round-bellied) and the other group (n = 4) had an upward curved abdominal contour (flat-bellied). An equal distribution of inspired gas between the lungs existed in both groups in dorsal recumbency. Flat-bellied horses maintained this equal distribution in lateral recumbency whereas in round-bellied hors...
Ellington JE, Samper JC, Jones AE, Oliver SA, Burnett KM, Wright RW.Formation of a spermatozoa ('sperm') reservoir in the mare is thought to occur through lectin-mediated sperm attachment to the oviductal epithelium. Once attached, prefertilization sperm survival is supported by oviductal factors. Cryopreservation of stallion sperm decreases the number of sperm attaching to oviduct epithelial cells (OEC) and the length of time these sperm survive. Quantification of in vitro interactions between sperm and OEC in a co-culture system may provide an assay for functional integrity of cryopreserved or fresh sperm samples. Additionally, superior additives for in vitr...
