The nervous system in horses is a complex network responsible for transmitting signals between different parts of the body. It consists of the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which comprises nerves that extend throughout the body. The nervous system regulates various physiological processes, including movement, sensation, and the coordination of bodily functions. It plays a critical role in processing sensory information and initiating appropriate responses. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and clinical implications of the equine nervous system, including its role in behavior, response to stimuli, and neurological disorders.
Bowker RM, Linder K, Sonea IM, Holland RE.The sensory innervation of the navicular bone (os sesamoideum distale) and its suspensory ligaments [ligamenta sesamoidea collateralia (CSL) and ligamentum sesamoideum distale impar or distal sesamoidean impar (DS-impar) ligament] and the navicular bursa (podotrochlearis) was examined in the neonatal foal using immunocytochemistry. With antisera raised to substance P (SP) and human calcitonin gene-related peptide (CGRP), immunoreactive nerves were demonstrated to innervate the CSL and navicular bursa. Within CSL, and SP- and CGRP-like nerves were present in the synovial lining of the navicular...
Roy DN, Peyton DH, Spencer PS.Horses grazing for prolonged periods on yellow star thistle (YST), a plant which grows wild in western parts of the United States, develop an extrapyramidal disorder known as nigropallidal encephalomalacia (NPE). Attempts have been made to identify, isolate, and characterize the toxins responsible for the disease in animals. Using the organotypic tissue culture system on mouse cortical explants as a specific assay method for neurotoxicological evaluation, it has been possible to isolate and characterize two potent neuroexcitotoxic compounds, aspartic and glutamic acids, the former being the ma...
Doxey DL, Pearson GT, Milne EM, Gilmour JS, Chisholm HK.A study of myenteric and submucosal plexuses was undertaken in the jejunum and ileum of horses and ponies in which no clinical or pathological evidence of intestinal abnormality was apparent. Complete transverse sections of the intestine, stained by a modified haematoxylin and eosin method, were examined using up to 20 sequential sections per animal. Information was gathered from adult, juvenile and fetal equidae. In adults, the longitudinal muscle layers were thinner than the circular muscle layers and the ileum had thicker layers compared to the jejunum. In adults, the submucosal plexus had ...
Doxey DL, Milne EM, Woodman MP, Gilmour JS, Chisholm HK.The number of neurons in the coeliacomesenteric ganglia and the myenteric and submucosal plexuses of the jejunum, ileum and small colon, and the pathological changes induced in them, were studied in various types of equine dysautonomia. In all forms of dysautonomia, severe and extensive neuron loss and damage occurred in the ileum. In acute and subacute dysautonomia, jejunal neuron loss and damage were severe, but in chronic cases significantly less loss or damage occurred. The damage followed the same pattern in the small colon but it was always less obvious than in the jejunum. The distribut...
Reed SM.Trauma to the nervous system in horses may involve the brain, brainstem, spinal cord, or peripheral nerves. Trauma may occur to any part of the nervous system with or without a fracture.
Gruys E, Beynen AC, Binkhorst GJ, van Dijk S, Koeman JP, Stolk P.The most important neurodegenerative diseases of the horse are reviewed. In addition to the literature, neurodegenerative diseases occurring in patients (horses, Mongolian Przewalski-horses, and two zebras) referred to the Utrecht Veterinary Faculty are mentioned. Neurodegenerative diseases described are: I. ataxia associated with: A/ static stenosis, B/ dynamic stenosis, C/ lesions at various locations in the central nervous system, D/ equine herpesvirus infections, E/ equine degenerative myelo-encephalopathy, or F/ cerebellar abiotrophy; II. equine motor neuron disease; III. grass sickness o...
Uzal FA, Doxey DL, Robles CA, Woodman MP, Milne EM."Mal seco" is a disease of unknown aetiology affecting horses in Argentina. It is similar to grass sickness, a primary dysautonomia of horses in Europe. A histopathological study of the brain stem nuclei of three horses with "mal seco" was performed. Changes were found that consisted of chromatolysis, cytoplasmic vacuoles, eosinophilic sphaeroids, and pyknotic and eccentric nuclei. These changes were most severe at the oculomotor, vestibular and abducent nuclei. The results provide further evidence to suggest that "mal seco" and grass sickness may be the same disease.
Sonea IM, Bowker RM, Robinson NE, Broadstone RV.Distribution of pulmonary nerves immunoreactive for either substance P or calcitonin gene-related peptide was determined, using immunohistochemical methods on healthy lungs from adult equids. The overall patterns of distribution of substance P and calcitonin gene-related peptide-like immunoreactivity were similar. Distribution of immunoreactive nerves was not uniform throughout the lungs; nerve fibers immunoreactive for these peptides were more frequently observed near the hilus of the lung than in the caudal lobes or in the periphery of the lung. Nerve fibers immunoreactive for substance P or...
Whalen LR, Wheeler DW, LeCouteur RA, Yovich JV, Boggie LC, Grandy JL, Kainer RA.Maximal conduction velocities of compound action potentials evoked by stimuli of 2 times threshold in the caudal cutaneous sural (CCSN) and medial cutaneous antebrachial (MCAN) nerves were determined by averaging potentials evoked and recorded through percutaneous needle electrodes. Mean maximal conduction velocities of compound action potentials were: CCSN = 61.3 +/- 2.0 meters/second (m/s) and MCAN = 56.4 +/- 2.8 m/s. To confirm accuracy of our percutaneous recordings, compound action potentials were recorded through bipolar chlorided silver electrodes from the exposed surfaces of fascicles ...
Pearson GT.The architecture and neurochemistry of the enteric nervous system was studied by use of whole-mount preparations obtained by microdissection of the horse jejunum. A myenteric plexus and two plexuses within the submucosa were identified. The external submucosal plexus lying in the outermost region of the submucosa had both neural and vascular connections with the inner submucosal plexus situated closer to the mucosa. Counts of neurones stained for NADH-diaphorase demonstrated the wide variation in size, shape and neurone content of individual ganglia in both the external and internal submucosal...
Skarda RT, Muir WW.Seven adult mares were used to determine the analgesic, CNS, and cardiopulmonary effects of detomidine hydrochloride solution after epidural or subarachnoid administration, using both regimens in random sequence. At least 1 week elapsed between experiments. A 17-gauge Huber point (Tuohy) directional needle was used to place a catheter with stylet into either the epidural space at the first coccygeal interspace or the subarachnoid space at the lumbosacral intervertebral junction. Catheters were advanced so that the tips lay at the caudal sacral (S5 to S4) epidural space or at the midsacral (S3 ...
Lowry TF, Forster HV, Korducki MJ, Forster AL, Forster MA.To gain insight into central and peripheral contributions to changes in breathing during hypoxia, we compared effects on breathing of reducing inspired PO2 (hypoxic hypoxia) with reducing arterial O2 content (CaO2) through elevation of carboxy-hemoglobin (COHb) (CO hypoxia). Twelve awake ponies were studied during 1 h of breathing room air followed by 6 h when COHb was increased to 25% and CaO2 was decreased by 17%. When COHb was increased, arterial PCO2 (PaCO2) increased gradually to 1.3 Torr above (P < 0.05) control level between 30 and 45 min of CO exposure. Pulmonary ventilation (VE) de...
Furuoka H, Mizushima M, Miyazawa K, Matsui T.We report the pathological findings of the skeletal muscle and peripheral nerves from a male 14-months-old thoroughbred horse showing idiopathic knuckling. The affected animal, when in staining position, presented knuckling at the fetlock joint of both forelegs, and dragged both fore- and hindlegs when attempting forward movement. The skeletal muscles demonstrated neurogenic atrophy characterized by the scattering of single angular fibers, groups consisting of five to ten angular fibers, and multiple fascicles of atrophic and hypertrophic fibers. The severity of changes tended to be a distal g...
Yu M, Wang Z, Robinson NE, Leblanc PH.The distribution of inhibitory nerves and the mediator of the inhibitory nonadrenergic noncholinergic (iN-ANC) nervous system were investigated in smooth muscle preparations from seven regions of equine airways. In tissues incubated with atropine and precontracted with histamine, electrical field stimulation produced frequency-dependent relaxation, and the magnitude of the relaxation decreased from trachea to central bronchi and was absent in peripheral airways. The degree of relaxation in bronchi was not simply a function of bronchial size or generation. Propranolol inhibited part of the rela...
Bowker RM, Rockershouser SJ, Vex KB, Sonea IM, Caron JP, Kotyk R.To determine whether the distal interphalangeal (DIP) joint directly or indirectly communicates with the navicular bursa (bursa podotrochlearis) and to identify sensory nerves in these synovial structures that might be desensitized by intra-articular injections of anesthetics, Evans blue dye in physiologic saline solution, Luxol fast blue dye with mepivicaine, or commercial latex was injected into the DIP joint (5 ml) or the navicular bursa (3 ml) of 152 digits obtained from horses or ponies at necropsy. The digits were frozen, cut with a band saw, and examined for distribution of dye or latex...
Yu M, Wang Z, Robinson NE.To determine the presence and function of alpha 2-adrenoceptors on cholinergic nerves innervating horse airway smooth muscle, the effects of some alpha 2-adrenoceptor agents on contractions of and acetylcholine (ACh) release from equine airway smooth muscle preparations were studied. Muscle contractions were elicited by either electrical field stimulation (EFS) or exogenous ACh. ACh release was induced by EFS and measured by high-pressure liquid chromatography and electrochemical detection. The alpha 2-adrenoceptor agonists clonidine (10(-7) to 10(-5) M) and UK-14,304 (10(-8) to 10(-6) M) conc...
Kamerling SG.The recognition and alleviation of animal pain is a growing veterinary and public concern. Pain can be of an acute or chronic nature with different behavioral manifestations. Physiologically, pain is a dynamic and complex phenomenon that produces changes in the central and autonomic nervous systems as well as in the endocrine system. Horses and other animals appear to possess an endogenous pain-suppressing system involving the brainstem and spinal cord. This system can modulate pain perception and the responses to it. The recently discovered endogenous opioid peptides (endorphins and enkephali...
Lunn DP, Cuddon PA, Shaftoe S, Archer RM.In an investigation of 2 closely related Miniature Horses with a history of excessive sleepiness, depression and episodes of collapse, a diagnosis of narcolepsy was made on the basis of neurological examination and pharmacological testing. Further investigations included electroencephalographic examination (EEG), and analysis of protein content, cell count and monoamine metabolite concentrations of lumbosacral cerebrospinal fluid (CSF). There were no abnormalities noted in the EEGs, and no consistent changes in CSF neurotransmitter metabolites in the narcoleptic horses when compared with 3 nor...
Bowker RM, Brewer AM, Vex KB, Guida LA, Linder KE, Sonea IM, Stinson AW.Two types of sensory receptors were located in the equine foot, using anatomic techniques. Histologic examination of stained hoof sections revealed lamellated corpuscles in the hoof dermis, which had many of the morphologic characteristics of Pacinian corpuscles. These sensory receptors were restricted to the palmar (caudal) aspects of the solar dermis of the heel. A second type of receptor was detected by use of immunocytochemistry, indicating apparently naked nerve endings containing the neuropeptide calcitonin gene-related peptide-like immunoreactivity in skin, solar dermal tubules, and the...
Bowker RM, Abhold RH, Caron JP, Sonea IM, Vex KB, Kotyk R.Immunocytochemical analysis of equine synovial membranes revealed presence of several neuropeptides, including substance P (SP), neurokinin A, and neuropeptide Y, in nerves of the radiocarpal, middle carpal, and metacarpophalangeal (fetlock) joints. Within the subsynovium, these neuropeptides were located perivascularly, whereas in the fronds, only neuropeptide Y was restricted to the vessels of the synovial membrane. Only SP and neurokinin A were found in the intimal layer. The intimal layer of the metacarpophalangeal joint contained more SP-immunoreactive fibers than were observed in the int...
Ruggles AJ, Beech J, Gillette DM, Midla LT, Reef VB, Freeman DE.A 13-year-old Quarter Horse gelding was referred for evaluation of a draining tract and fracture of the right hemimandible of 4 weeks' duration. Two days prior to admission, the horse had developed pigmenturia. Radiography of the mandible revealed a fracture of the vertical ramus of the right hemimandible, loss of the right lower second premolar, and osteomyelitis involving an extensive portion of the hemimandible. Ultrasonography of the left kidney revealed loss of normal renal architecture. Histologic examination of tissue obtained from the right hemimandible revealed granulomatous osteomyel...
Jackman BR, Baxter GM, Doran RE, Allen D, Parks AH.The medical records of 57 horses that had palmar digital neurectomy performed between 1984 and 1990 were reviewed. Neurectomies were performed either by transection and electrocoagulation (47 horses) or by the guillotine technique (10 horses). Middle-aged geldings, Quarter Horses, and Thoroughbreds were significantly over-represented when compared with the hospital population. Horses used as hunter/jumpers also appeared to be over-represented. Complications occurred in 17 (34%) of the 50 horses for which follow-up information was obtained. Recurrence of heel pain was the most common complicati...
Scholes SF, Vaillant C, Peacock P, Edwards GB, Kelly DF.The degeneration of enteric neurones has been recorded in grass sickness, but the distribution of the lesions in the gut and their possible relationship with the severity of the clinical signs has not been established. Samples obtained from 11 anatomically defined sites along the gastrointestinal tract of eight control horses without gastrointestinal disease, five horses with acute grass sickness and three horses with chronic grass sickness were examined histologically. The organisation of the enteric ganglia was similar to that in other large mammalian species. Minor exceptions included the p...
Prieto D, Hernandez M, Rivera L, Ordaz E, Garcia-Sacristan A.The aim of the present study was to determine the distribution and density of catecholaminergic nerve fibres and cells in the equine ureter by using immunohistochemical techniques to localise the enzyme tyrosine-hydroxylase (TH). TH-immunoreactive (TH-IR) nerve fibres entered the wall of the ureter as adventitial nerve trunks accompanying the blood vessels. These trunks repeatedly branched as they coursed through the muscular layer towards the epithelium, forming muscular, perivascular and subepithelial nerve plexuses. TH-IR nerve fibres were especially numerous in the pelvic and intravesical ...
Sonea IM, Bowker RM, Broadstone RV, Robinson NE.The tone of respiratory smooth muscle is largely determined by the input from autonomic nerves. The distribution of adrenergic and selected nonadrenergic, non-cholinergic (NANC) nerves in the normal equine trachealis muscle was investigated using immunohistochemistry. The smooth muscle of the trachealis was found to contain numerous nerves immunoreactive for an enzymatic marker of adrenergic nerves, as well as many nerves immunoreactive for a putative NANC neurotransmitter, peptide histidine isoleucine, a potent bronchodilator. The tissue surrounding the respiratory smooth muscle contained num...
Cohen ND.Neurologic evaluation should be performed in horses with diseases of the head. Although neurologic examination should focus on assessing behavior, mental status, and cranial nerve evaluation, evaluation of neurologic function of other body regions should be performed. Neurologic evaluation of the head can be performed expediently by practitioners to provide useful diagnostic and prognostic information. The numerous causes of dysphagia can be classified as obstructive, painful, or neurogenic. Common causes of neurogenic dysphagia are summarized, and methods for initial diagnosis and management ...
Sisken BF, Zwick M, Hyde JF, Cottrill CM.This review covers the development and maturation of the cerebellum of the horse and compares this developmental sequence with that of man, mouse and chicken. These comparisons attempt to correlate morphological and neurochemical features, developmental time and functional performance necessary for survival at birth. Although there is great disparity between these 3 species, the basic anatomical structures of the cerebellum are present as are specific cellular groups, synapses and neurochemical markers. In addition to this structural homogeneity, other attributes of the cerebellum are its easi...
Dorman D.The central nervous system's extrapyramidal system provides involuntary motor control to the muscles of the head, neck, and limbs. Toxicants that affect the extrapyramidal system are generally clinically characterized by impaired motor control, which is usually the result of basal ganglionic dysfunction. A variety of extrapyramidal syndromes are recognized in humans and include Parkinson's disease, secondary parkinsonism, other degenerative diseases of the basal ganglia, and clinical syndromes that result in dystonia, dyskinesia, essential tremor, and other forms of tremor and chorea. This cha...
Delli-Rocili MM, Cribb NC, Trout DR, Thomason JJ, Valverde A.To compare the effectiveness of a paravertebral nerve block vs local portal blocks for laparoscopic closure of the nephrosplenic space in standing sedated research horses. Methods: Randomized clinical trial. Methods: Twelve horses were randomly allocated to two groups (n = 6 per group), paravertebral block of nerves T , L , and L or local blocks of the three laparoscopic portals. Methods: Horses were sedated with dexmedetomidine (4 μg/kg IV and constant rate infusion [CRI] of 2.5 μg/kg/h) and morphine (50 μg/kg IV and CRI of 30 μg/kg/h). According to group allocation, 20 mL of either lid...
Griffiths IR, Lusk SA, Kyriakides E, Smith S.Neurofilaments (NF) are composed of three polypeptides of differing molecular size, termed NF-L, NF-M and NF-H. The NF-H and, to a lesser degree, NF-M components are phosphorylated. In the majority of normal neurones, the location of phosphorylated NF is confined to neuronal processes, particularly the axon, and excluded from the perikaryon. Cell bodies of autonomic neurones of the rat do not contain phosphorylated NF. In many disease states, phosphorylated NF accumulate in the neuronal cell body and therefore in most circumstances their presence indicates abnormality. This paper reports that ...
Nessler JN, Delarocque J, Kloock T, Twele L, Neudeck S, Meyerhoff N, Riese F, Cavalleri JV, Tipold A, Feige K, Niebuhr T.To determine whether sensory nerve conduction stimulus threshold measurements of the infraorbital nerve are able to differentiate horses with idiopathic trigeminal-mediated headshaking (i-TMHS) from healthy horses and from horses with secondary trigeminal-mediated headshaking (s-TMHS). In a prospective trial, headshaking horses were examined using a standardized diagnostic protocol, including advanced diagnostics such as computed tomography and 3-Tesla-magnetic resonance imaging (MRI), to differentiate s-TMHS from i-TMHS. Clinically healthy horses served as controls. Within this process, patie...
Machado M, Camacho AL, Coubrough C, R R Queiroz-Machado C, Custodio C, Barros CSL, Riet-Correa F, Menchaca A.We reported thirteen cases of bilateral stringhalt associated with Hypochaeris radicata that occurred in horses in Uruguay during a severe drought in the summer of 2023. All horses were affected chronically and progressively by bilateral hyperflexion of hindlimbs. In two severely affected horses, the main histological lesions included neuronal chromatolysis and axonal spheroids in the ventral gray horn in the lumbar and sacral spinal cord and axonal degeneration and digestion chambers in ventral roots fibers and long peripheral nerves. We suggest that in addition to injuries to peripheral nerv...
Scharf A, Cheng TY, Urion R, Hostnik E.The objective of this study was to optimize an MRI-based diffusion tensor imaging (DTI) protocol for imaging the plantar nerves at the level of the tarsus in normal equine limbs. Methods: 12 pelvic cadaver limbs from horses without evidence of proximal suspensory pathology were imaged with a 3T MRI system. Methods: For diffusion-weighted imaging, b values of 600, 800, and 1,000 s/mm2 were tested. Data were processed with DSI Studio. Cross-sectional areas of the medial and lateral plantar nerve along the plantar tarsus were recorded. The length and number of fiber tracts, signal-to-noise ratio,...
den Boer JC, Klip H, Blonk A, Lenselink M, Kaijdoe SPT, Tielkes M, van Zandbeek A, Bres G, Herinx M, Staal WG, Rommelse N.For people with autism spectrum disorder (ASD), daily life can be highly stressful with many unpredictable events that can evoke emotion dysregulation (ED): a strong difficulty with appropriately negative affect regulation. For some of the patients with ASD, treatment as usual does not prove to be effective for ED. They may be at risk of life-long impairment, development of other disorders and loss of motivation for most regular forms of therapy. A highly promising method that may prove effective for therapy-resistant individuals with ASD is Psychotherapy incorporating horses (PIH). PIH uses t...
Behroozi M, Graïc JM, Gerussi T.Diffusion-weighted Imaging (DWI) is an effective and state-of-the-art neuroimaging method that non-invasively reveals the microstructure and connectivity of tissues. Recently, novel applications of the DWI technique in studying large brains through imaging enabled researchers to gain insights into the complex neural architecture in different species such as those of (e.g., horses and rhinos), (e.g., bovids, swines, and cetaceans), and (e.g., felids, canids, and pinnipeds). Classical tract-tracing methods are usually considered unsuitable for ethical and practical reasons, in large animals...
Mascaró Triedo CE, Karar S, Abunemeh M, Portier K.Pupillometry is used in humans to monitor pain, nociception and analgesia. This single-center, non-randomized, non-blinded intervention trial, evaluated the effect of nose twitching on the pupil size in awake, sedated, and anesthetized horses. Pupil height (H) and length (L) were measured before (Be) and after (Af) nose twitching in fourteen non-painful adult awake horses (T0). The percentage of variation (PSV) was calculated (PSVTn = [(TnAf-TnBe)/TnBe]*100). Measurements were repeated (Tn) after acepromazine (0.04 mg kg IV) (T1), romifidine (0.04 mg kg IV) (T2), morphine (0.1 mg...
Tan Yi Shean L, Milne EM, Shaw DJ, Maxwell S, Del-Pozo J.Lipofuscin is a complex mixture of highly oxidized, cross-linked macromolecules that accumulates in neurons with age and some neurodegenerative diseases. Equine dysautonomia (ED) is a polyneuropathy that mainly affects autonomic and enteric nervous systems, resulting in alimentary tract dysfunction. Our main aim was to determine whether neuronal lipofuscin increased with increasing duration of ED. We investigated the prevalence of lipofuscin in cranial cervical ganglia of horses with acute (AED), subacute (SED), and chronic ED (CED), young controls (of similar age to ED cases), and aged contro...
Izquierdo-Moreno J, de Paz MI, Manso-Díaz G, Villalba-Orero M, López-Sanromán J.An accurate evaluation of the degree of sedation is mandatory to adjust the dosage of sedative drugs. Objective: To determine the correlation between head height above the ground and ataxia degree in horses sedated with detomidine and the correlation existing between accelerometric variables and both parameters. Methods: Retrospective study. Methods: Twelve horses were given 0.01 mg/kg of detomidine hydrochloride iv. Measured accelerometric parameters, with one accelerometer positioned between both sacral tuberosities, included speed, stride frequency and length, regularity, dorsoventral, lo...
Flores JEM, Terrazas A, Lara Sagahon AV, Aleman M.Parasympathetic tone activity (PTA) in response to nociceptive stimulus in conscious non-sedated horses is unknown. Objective: Study PTA, heart rate (HR), and horse grimace scale (HGS) at rest and during mechanical nociceptive stimulation. Methods: Ninety healthy young adult horses (females, males): 30 each of Friesians, Quarter Horses, and Warmbloods. Methods: Prospective control study. The study consisted of habituation to equipment (Day 1), baseline recordings (Days 2 and 3), and nociceptive testing applying mild pressure to the metacarpus (Day 4). Parasympathetic tone, HR, and HGS were rec...
Tomberg C, Petagna M, de Selliers de Moranville LA.Spontaneous eye blinks are brief closures of both eyelids. The spontaneous eye blink rate (SEBR) exceeds physiological corneal needs and is modulated by emotions and cognitive states, including vigilance and attention, in humans. In several animal species, the SEBR is modulated by stress and antipredator vigilance, which may limit the loss of visual information due to spontaneous eye closing. Here, we investigated whether the SEBR is modulated by attention in the domestic horse (Equus caballus). Our data supported previous studies indicating a tonic SEBR specific to each individual. We also fo...
de Oliveira Ferreira LV, Maia L, de Andrade DGA, da Costa Kamura B, de Carvalho M, Amorim RM.Cell-based therapy has emerged as a promising strategy for treating peripheral nervous system (PNS) injuries across different species. However, there is a scarcity in the literature regarding the transplantation of mesenchymal stem cells (MSCs) for treating PNS injuries in horses. This report aims to describe the therapeutic potential of equine MSC transplantation in two horses with chronic traumatic facial nerve paralysis. Both horses presented with lip ptosis and right deviation of the nostril and upper lip, being clinically diagnosed with left facial nerve paralysis. Due to the refractorine...
Yamaga T, Tagami M, Takeyama A, Kato F, Suzuki T, Tagami M, Tsuzuki N.Computed tomography (CT) offers high-resolution, three-dimensional imaging, making it particularly valuable for assessing complex structures, such as the head, especially when conventional radiography and endoscopy are insufficient for a definitive diagnosis. Herein, we present two cases of equine cranial disorders resulting from congenital malformations. In case 1, which had a dentigerous cyst, CT images confirmed the location of the ectopic tooth within the skull and a detailed fistula tube. In case 2, which had temporohyoid osteoarthropathy, CT examination revealed that the stylohyoid bone ...
Mota-Rojas D, Whittaker AL, Bienboire-Frosini C, Buenhombre J, Mora-Medina P, Domínguez-Oliva A, Martínez-Burnes J, Hernández-Avalos I....Recognizing that nonhuman animals are sentient beings has increased interest in studying their emotional state. Similar to humans, research has shown that some nonhuman mammals can modify facial expressions by contraction/relaxation of facial muscles according to their affective state. From a neurophysiological perspective, emotions are processed in several brain structures, mainly from the limbic system, such as the hypothalamus, hypophysis, hippocampus, prefrontal cortex, and amygdala. The converged pathways between the amygdala, the motor cortex, and its projections to the facial nerve cont...
Wonghanchao T, Sanigavatee K, Poochipakorn C, Huangsaksri O, Chanda M.Changes in resting heart rate (HR) and HR variability (HRV) are utilised to assess training effects in horses. However, limited research has examined how these variables reflect training effects during exercise sessions and recovery periods, particularly in horses of different ages. This study investigated how HR and HRV changed during exercise sessions and recovery periods in untrained adult horses (UAHs; = 9) and geriatric horses (UGHs; = 9). HR and HRV were measured before and during a 54 min exercise bout over a 12-week training programme. Mixed-effects model with Greenhouse-Geisser corr...
Vasconcelos de Sousa AL, Riet-Correa F, Botelho de Castro M, Machado M.We reviewed the history, epidemiology, clinical signs, pathology, pathogenesis, treatment, control, and prophylaxis of Sorghum poisoning in livestock. Economic losses in the livestock industry associated with sorghum have been reported since the 19th century. Hyperacute/acute poisoning associated with cyanide (HCN) or nitrate/nitrite frequently occurs in ruminants that consume high quantities of growth and regrowth sorghum after drought, followed by rainfall, respectively. Chronic cystitis-ataxia syndrome primarily affects horses after weeks of grazing on sorghum pastures, while congenital art...
Käfer-Karrer MJ, de Preux M, Van der Vekens E, Mattei LI, Kuhlmann J, Klopfenstein Bregger MD, Easley JT, Koch C.To describe the repair of a fractured cranial articular process (AP) of the sixth cervical vertebra (C6) with cortex screws placed in lag fashion using computer-assisted surgery. Methods: A 12-year-old Swiss Warmblood gelding. Methods: Case report. Methods: The gelding was presented with neck pain and ataxia after a fall. A fracture of the right cranial AP of C6 was identified on radiographs. The fracture was repaired by internal fixation with two 4.5 mm cortex screws of 58 and 48 mm length placed in lag fashion using computer-assisted surgery. Results: During general anesthesia, it was su...
Lloyd-Edwards RA, Mulders E, Sloet van Oldruitenborgh-Oosterbaan MM, Veraa S. Headshaking is a common condition in horses, most cases are presumed idiopathic/trigeminal-nerve mediated. Diagnostic work-up of a headshaking horse may involve computed tomography (CT) of the head to exclude causative structural pathology. The relevance of the presence and severity of hyoid apparatus findings at CT to headshaking is unknown. A retrospective analysis of CT changes in the hyoid apparatus in horses was carried out. Comparisons were performed between horses with signs of headshaking and a control population and a subgroup of horses with signs of headshaking and no other 'likely...
Maurer T, de Preux M, Precht C, Vidondo B, Koch C.To assess the accuracy of computer-assisted surgery (CAS) of equine cervical vertebrae using a purpose-built cervical frame (CF) for neck stabilization. Methods: Experimental cadaveric study. Methods: Six whole fresh equine cadavers. Methods: Cadavers were positioned in dorsal recumbency with the neck extended within the CF. A cone-beam computed tomography (CBCT)-based surgical navigation system with optical tracking was used. A ventral approach exposed cervical vertebrae C3-C5. In each cadaver, 12 drill corridors were prepared with the patient tracker on the CF (position CF), followed by 12 c...
de Sousa ALV, de Sousa DER, de Macêdo IL, de Albuquerque Cerqueira L, da Fonseca YNG, Oliveira AB, das Chagas LVS, Gonçalves GB, Veado HC....This report describes the first documented case of intracerebral hemorrhage (ICH) in a horse following Bothrops snakebite envenomation. A 3-year-old mare developed acute kidney injury, systemic hemorrhage, and neurological signs before euthanasia. Postmortem findings confirmed massive ICH with intralesional venom identified by immunohistochemistry. Delayed treatment and insufficient antivenom likely contributed to the outcome. This case highlights the potential for cerebrovascular complications following Bothrops snakebite envenomation in horses, which may present as subtle neurological signs....
de la Cuesta-Torrado M, Velloso Alvarez A, Cárdenas-Rebollo JM, Neira-Egea P, Vitale V, Cuervo-Arango J.Understanding of equine herpesvirus-1 (EHV-1) myeloencephalopathy (EHM) is complicated by disparities among studies. Objective: Compare clinical findings and outcome in horses involved in 2 recent EHM outbreaks. Methods: Twenty-five and 10 horses affected during 2 natural EHM outbreaks were admitted to a veterinary teaching hospital (VTH) in 2021 and 2023, respectively. Methods: Data collected from the VTH and surveys completed by riders and horse owners were analyzed retrospectively. Results: No risk factors associated with EHM development showed significant differences between the outbreaks;...
This research investigates the human-horse bond, aiming to unveil the physiological mechanisms regulating interspecies interactions. We hypothesized observing a physiological synchronization in human-horse dynamics, akin to human interactions. Through time-frequency Granger causality analysis of heart rate variability (HRV) and behavioral data, this study reveals the establishment of bidirectional synchronization in HRV between humans and horses. The coupling directionality is influenced by behavior and familiarity. In exploration scenarios led by horses, bidirectional interactions occur, part...
Mannini A, Ellero N, Urbani L, Balboni A, Imposimato I, Battilani M, Gialletti R, Freccero F.A 17-year-old mare presenting with acute fever, weakness and bladder dysfunction was diagnosed with equine herpesvirus myeloencephalopathy (EHM). The mare become transiently recumbent, underwent parenteral fluid therapy, plasma infusion, steroidal/nonsteroidal anti-inflammatory drugs (SAID/NSAIDs) and bladder catheterization. After 10 days the mare was hospitalized. Neurological evaluation revealed ataxia and proprioceptive deficits mainly in the hind limbs. The mare was able to stand but unable to rise from recumbency or walk. Secondary complications included Escherichia coli cystitis, cornea...
Jortner BS, Scarratt WK, Modransky PD, Walton A, Perkins SK.Neuropathologic examination revealed axonal swelling and breakdown leading to Wallerian degeneration of affected myelinated nerve fibers in the spinal cord white matter of four young horses with equine cervical compressive myelopathy. Immunohistochemical reactions for the cell stress protein ubiquitin revealed an enhanced presence in the swollen axons, which may reflect a role for ubiquitin in the neuronal catabolic process of axonal compression and degeneration in this myelopathy.
Irby NL.A complete neuro-ophthalmologic assessment is relatively simple, requires minimal instrumentation and should be performed as part of every complete ophthalmic and neurologic examination. This article has summarized the tests that comprise and the species-specific details of the complete neuro-ophthalmologic of the equine patient. Selected causes of sudden blindness in the horse were summarized and some common neuro-ophthalmic conditions with significant ophthalmic consequences, such as facial nerve paralysis, were discussed. Split-lid tarsorrhaphies, which are indicated but rarely used in case...
Tate LP, Evans LH.Cryoneurectomy was performed experimentally on 10 digital plantar nerves of normal horses. All nerves were frozen to -30 C, using a double freeze-thaw cycle. Nerves were harvested at 10 days and at 4, 12, 16, and 24 weeks and were examined histologically for evidence of regeneration. The terminal portion of the transected nerves treated with cryosurgery did not have any signs of regeneration or neuroma formation at these periods. Cryoneurectomy was performed on 101 nerves of 32 horses with diseases requiring neurectomy. Twenty-seven of these nerves had been subjected to previous neurectomy, an...
