"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
Malone ED.Many compounds are being investigated for the control of symptoms of osteoarthritis in people and animals. Ideally, treatment should include analgesia, inflammation control, and chondroprotection. With further progress in this area, combination therapies tailored to the needs of the individual animal should enable us to maximize efficacy and minimize side effects. Only a few of the newer therapies and pharmaceutic agents have been investigated in the horse, however. With more rigorous investigation, they may be determined to be ineffective or unsafe. Meanwhile, as much information should be ga...
Fermaglich DH, Horohov DW.Although vaccine manufacturers make no specific recommendations regarding the vaccination of older horses and ponies, the similarities in age-induced immunologic changes between human beings and equids suggests that similar vaccination recommendations should be followed. The need for vaccination of the older horse depends, of course, on the relative risk of exposure for the individual horse. Particular care should be taken when using attenuated vaccine products because these live agents may pose a unique risk to the older individual. Immunization with inactivated agent vaccines is likely to be...
Boldt E.The use of complementary and alternative veterinary medicine continues to grow within the veterinary community. As more clients seek out complementary and alternative medicine for their own health care, they begin to seek out these forms of therapy for their animals. For the equine practitioner, this includes those clients with geriatric animals. It is hoped that this article provides some insight into what conditions may be helped with CVM (complementary veterinary medicine) and when an equine practitioner may want to consider CVM as a form of therapy for the geriatric horse.
Sage AM.Almost all equine cardiac diseases may affect the geriatric horse. This article focuses on those cardiac diseases that are most common in the older horse, including degenerative valve disease, aortocardiac fistula, and congestive heart failure. Other cardiac diseases, such as bacterial endocarditis, pericarditis, and arrhythmias, are seen in all age groups of horses and are beyond the scope of this article.
Madill S.Functional alterations within the reproductive system and in other supporting systems may limit the reproductive capacity of geriatric patients; however, the age of onset and degree of compromise show wide individual variation. Aging of the hypothalamopituitary-ovarian axis in the mare manifests as delayed entry to the breeding season, prolonged follicular phases, reduced response to ovulation induction, irregular cycles, oocyte defects, increased early embryonic death, and, eventually, persistent anestrus. Aging of the reproductive tract may increase her susceptibility to endometritis, compro...
Hunt RJ.There are few diseases that instill a comparable sense of doom in the mind of a treating veterinarian as laminitis. There is a feeling of cautious optimism when a horse with laminitis responds favorably to treatment. Although this optimism all too often proves false when treating laminitic patients, management of the patient afflicted with chronic laminitis can be rewarding. Through diligent and careful client communication and instruction, many geriatric patients with chronic laminitis can be maintained for years as comfortable companions, for light riding use, or as productive breeding anima...
Paradis MR.Owners of older horses have generally owned them for a long time. They have developed a bond that is similar to that seen with companion animals. Their desire to have their animal(s) age gracefully with comfort and mobility has stirred research in the field of equine geriatric medicine. Equine geriatric medicine is to the first decade of the twenty-first century as neonatal medicine was to the 1980s. Hopefully, the demographics discussed in this article highlight area where research can be most helpful.
Dickinson CE, Lori DN.In the absence of debilitating medical problems, the geriatric horse can maintain a normal body condition when provided with an appropriate diet, adequate shelter, and preventive health care that includes regular dental care and deworming. Failures in management can lead to inadequate nutritional support, exposure to adverse environmental conditions, advanced dental disease, parasitism, and failure to detect developing medical problems. All these circumstances can lead to loss of condition and debilitation in the aged horse. Weight loss in the aged horse should be approached with an understand...
Davis E, Rush BR.Recurrent airway obstruction is a condition that affects some older horses maintained in confinement. Clinical signs range from exercise intolerance with occasional cough to dyspnea at rest. Bronchoalveolar lavage cytology is characterized by neutrophilic leukocytosis (15%-85%) and is recommended for making the diagnosis in horses with mild to moderate disease. Environmental management combined with periodic bronchodilator and antiinflammatory corticosteroid therapy yields the best prognosis for disease remission.
Love LB, Choi YH, Love CC, Varner DD, Hinrichs K.Two experiments were conducted to determine the effects of storage on equine ovaries or isolated oocytes. Ovaries were collected at an abattoir and were maintained at room temperature during collection and transport (3-9h total). After arrival at the laboratory, ovaries were divided into three groups: immediate oocyte collection (control), storage at room temperature overnight (15-18 h) before oocyte collection, or storage at 4 degrees C overnight before oocyte collection. Collected oocytes were cultured in maturation medium for 24h. There was a significant increase in the proportion of oocyte...
Graham BP.Dental care in any horse need not be looked at as the difficult challenge it used to be before the days of sedation and tungsten carbide and diamond cutting wheels. Horses are living longer and more comfortable lives thanks, in part, to the advancements of dental care and special dietary rations. With the evolution of the horse's place in family circles today, people want the best care possible for their animals. Dentistry has become an important part of that care.
Klonisch T, Steger K, Kehlen A, Allen WR, Froehlich C, Kauffold J, Bergmann M, Hombach-Klonisch S.We employed molecular and immunological techniques to investigate the expression of INSL3, a member of the insulin-like superfamily, in prepubertal testis, postpubertal testes exhibiting normal and disturbed spermatogenesis, and cryptorchid testes of male horses. In addition, the partial cDNA coding sequences of the equine homologue of the human relaxin/INSL3-receptor Lgr8 were determined. Nonradioactive in-situ hybridization with a cRNA probe for equine Insl3 and immunohistochemistry with a specific rabbit INSL3 antiserum localized Insl3 transcripts and immunoreactive INSL3 ligand to Leydig c...
Botha CJ, Naudé TW.Well-known plant poisonings such as 'dunsiekte' (seneciosis) and 'jaagsiekte' (crotalariosis) of horses in southern Africa are briefly reviewed. Relatively unfamiliar mycotoxicoses such as stachybotryotoxicosis and perennial rye grass staggers and potentially occurring exotic intoxications such as equine nigropallidal encephalomalacia and ergot alkaloid poisoning are also discussed. This article is aimed at informing the southern African equine practitioner about probable poisonings that might occur locally in horses.
Górecka R, Sitarska E, Kluciński W.Antioxidant defences interact to form an integrated system. There is no comprehensive and uniform view on issues concerning the antioxidant status in horses. Therefore, the aim of the present study was to estimate antioxidant parameters in horses of different age, sex and breed as well as environment and relationship between different antioxidants. Parameters of selected antioxidants including superoxide dismutase (SOD), glutathione peroxidase (GSH-px), total antioxidant status (TAS), ceruloplasmin (CP), bilirubin, uric acid, zinc, copper and selenium were determined in blood of 80 clinically ...
Okulewicz A, Lonc E, Borgsteede FH.The biology of the ascarid nematodes has been discussed in the context of their important economic role in farm animals, pet animals and zoo animals with special attention to carnivores and primates. In farm animals, infection with the most common roundworm of horses (Parascaris equorum) and swine (Ascaris suum) depend on many factors such as environmental conditions (larval development in the egg and egg survival), age of the host, breed, husbandry system, hygiene and treatment schedule. The monoxenic ascarids Toxocara canis and T. cati are the most important nematodes in carnivorous animals ...
Donahue JM, Williams NM, Sells SF, Labeda DP.Over the course of the past decade, actinomycetes have been isolated from the placentas of horses diagnosed with nocardioform placentitis. The incidence of this infection has generally been low, with typically no more than 30 animals affected in most years, but the incidence increased through 1999, with placentas from 144 mares found to be infected. Approximately half of the cases result in loss of the foal. A typical actinomycete with branching mycelium was isolated from placental lesions, and a comparison of the sequence of the 16S rDNA gene against the public databases indicated a relations...
Fintl C, Milne EM, McGorum BC.To determine whether urinalysis can aid the diagnosis of equine grass sickness, samples of urine from 15 horses with acute grass sickness, eight horses with subacute grass sickness, 17 co-grazing horses and 17 stabled control horses were analysed. The samples from all of the horses with grass sickness had a significantly higher specific gravity, higher protein and creatinine concentrations and a significantly lower pH; the samples from the horses with acute grass sickness also had significantly higher glucose concentrations. These differences may support a diagnosis of grass sickness but they ...
Törneke K, Ingvast-Larsson C, Boström A, Appelgren LE.The distribution of muscarinic receptors in equine airways was investigated using autoradiography. Frozen sections of tissue from six different levels in the bronchial tree, from the trachea to the distal bronchioles, were incubated in vitro with 1.5 nmol/L of the muscarinic receptor antagonist 1-[N-methyl-3H]scopolamine methyl chloride (3H-NMS). In addition, the subtype pattern of muscarinic receptors was investigated in equine tracheal smooth muscle using radioligand binding with methoctramine, tripinamidc, 4-DAMP-methiodide and pirenzipine as competitors against the binding of 1.3 nmol/L 3H...
Dirikolu L, Hughes C, Harkins D, Boyles J, Bosken J, Lehner F, Troppmann A, McDowell K, Tobin T, Sebastian MM, Harrison L, Crutchfield J, Baskin SI....The epidemiological association between black cherry trees and mare reproductive loss syndrome has focused attention on cyanide and environmental cyanogens. This article describes the toxicokinetics of cyanide in horses and the relationships between blood cyanide concentrations and potentially adverse responses to cyanide. To identify safe and humane blood concentration limits for cyanide experiments, mares were infused with increasing doses (1-12 mg/min) of sodium cyanide for 1 h. Infusion at 12 mg/min produced clinical signs of cyanide toxicity at 38 min; these signs included increased heart...
Hughes C, Lehner F, Dirikolu L, Harkins D, Boyles J, McDowell K, Tobin T, Crutchfield J, Sebastian M, Harrison L, Baskin SI.An epidemiological association among black cherry trees (Prunus serotina), eastern tent caterpillars (Malacosoma americana), and the spring 2001 episode of mare reproductive loss syndrome in central Kentucky focused attention on the potential role of environmental cyanogens in the causes of this syndrome. To evaluate the role of cyanide (CN (-)) in this syndrome, a simple, rapid, and highly sensitive method for determination of low parts per billion concentrations of CN (-) in equine blood and other biological fluids was developed. The analytical method is an adaptation of methods commonly in ...
Park SC, Yun HI.The pharmacokinetic properties of norfloxacin-glycine acetate (NFLXGA) were determined in six horses following a single intravenous (i.v.) and intramuscular (i.m.) dose of 4 mgkg(-1) body weight. Following i.v. and i.m. administration, the plasma drug concentrations were best fitted by an open two-compartment model with a rapid distribution phase. After i.v. NFLXGA administration, the distribution (t(1/2alpha)) and elimination half-life (t(1/2beta)) were 0.42 (0.05) and 5.44 (1.36)h. The volume of distribution of NFLXGA at steady state (Vd(ss)) was 2.19 (0.53) Lkg(-1). After NFLXGA i.m. admini...
Ainsworth DM, Appleton JA, Eicker SW, Luce R, Julia Flaminio M, Antczak DF.The effect of strenuous exercise on the mRNA concentrations of interleukin-12p35 subunit (IL-12p35), interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in equine pulmonary and peripheral blood mononuclear cells (PBMCs) was investigated. We hypothesized that strenuous exercise would suppress the expression of IL-12p35, IFN-gamma and augment the expression of IL-4. Eleven horses were randomly divided into two groups, a stall-confined control group (n=5) and an exercise-conditioned treatment group (n=6). Bronchoalveolar and PBMCs were obtained from horses in the treatment group prior to the co...
Hobo S, Yoshihara T, Oikawa M, Jones JH.An enzyme-linked immunosorbent assay (ELISA) was developed for equine surfactant proteins SP-A and SP-D in bronchoalveolar lavage fluid (BALF). Anti-equine SP-A or SP-D monoclonal antibodies (mAb) were produced by hybridoma technology, purified by the antibody purification reagent, and analysed by Western blotting analysis. The immunoreaction (two-site sandwich ELISA) with a mAb, peroxidase-labelled mAb and BALF sample was carried out simultaneously and analytical recovery and precision were assayed. Six mAb for SP-A and four mAb for SP-D were successfully cloned in limiting dilution to monocl...
Walendy L, Goehring LS, Zablotski Y, Weyh T, Matiasek K, May A.Transcranial magnetic stimulation (TMS) has been successfully used in horses to evaluate function and integrity of descending motor pathways in patients affected by neurological gait abnormalities. In preceding studies, lengthening latency times (LT) of cranially evoked limb muscle potentials have been considered a reliable diagnostic parameter. Standardized settings use device output signal intensities of 100%. The aim of this study was to determine the effect of submaximal stimulation intensities (SI) and to determine the minimum coil output necessary to evoke motor unit potentials. As an ad...
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...
Gómez MD, Menendez-Buxadera A, Valera M, Molina A.A total of 71 522 records (from 3154 horses) with the times per kilometre (TPK), recorded in Spanish Trotter horses (individual races) from racing performances held from 1991 to 2007, were available for this study. The TPK values for the different age groups (young and adult horses) and different distances (1600-2700 m) were considered as different traits, and a bi character random regression model (RRM) was applied to estimate the (co)variance components throughout the trajectory of age groups and distances. The following effects were considered as fixed: the combination of hippodrome-dat...
Marlin DJ, Schroter RC, Scott CM, White S, Nyrop KA, Maykuth PL, Harris PA.Anhidrosis has been recognised for over half a century, but despite some excellent epidemiological studies, there has been little progress in understanding the aetiology of the condition. Using a modified ventilated capsule, we obtained dynamic, quantitative data on sweating responses in anhidrotic horses and normal sweating controls from the same environment. Ten horses with current seasonal anhidrosis and 10 matched normal sweating controls were selected. Each horse was given two 10 min infusions of 1 and 2 micrograms/kg/min adrenaline, separated by at least 6 h. Sweating responses and skin ...
Step DL, Cummings JF, de Lahunta A, Valentine BA, Summers BA, Rowland PH, Mohammed HO, Eckerlin RH, Rebhun WC.A 9-year-old Quarter Horse mare was examined because of progressive weight loss, weakness, muscle atrophy and tremors, and behavioral change. Selenium and glutathione peroxidase assays, blood lead analysis, erythrocyte transketolase analysis, pseudorabies and Borrelia burgdorferi serology, electromyography, and CSF analysis were performed. Motor neuron degeneration was diagnosed by microscopic examination of neural tissues. The cause of the disease was not substantiated, but several possibilities were excluded via diagnostic testing. Diagnosis of motor neuron degeneration in horses may be made...
Johnson EB, Mackay RJ, Hernandez JA.OBJECTIVE-To estimate prevalence of and identify factors associated with anhidrosis in horses in Florida. Design-Cross-sectional study and case-control study. ANIMALS-4,620 horses on 500 farms. PROCEDURES-A questionnaire was structured and mailed to farm owners or managers to obtain information related to diagnosis of anhidrosis in horses and exposure factors associated with this condition. The frequency of investigated farm- and animal-level factors was compared between farms and horses affected and not affected with anhidrosis, respectively. RESULTS-The prevalence of anhidrosis was 11% at th...
Selberg K, Werpy N.Ungual cartilage ossification in the forelimb is a common finding in horses. Subtle abnormalities associated with the ungual cartilages can be difficult to identify on radiographs. Magnetic resonance (MR) imaging findings of 22 horses (23 forelimbs) with a fracture of the distal phalanx and ossified ungual cartilage were characterized and graded. All horses had a forelimb fracture. Eleven involved a left forelimb (seven medial; four lateral), and 12 involved a right forelimb (five medial; seven lateral). All fractures were nonarticular, simple in configuration, and nondisplaced. The fractures ...
Milligan M, Kukanich B, Beard W, Waxman S.Lidocaine is administered as an intravenous infusion to horses for a variety of reasons, but no study has assessed plasma lidocaine concentrations during a 12-h infusion to horses. The purpose of this study was to evaluate the plasma concentrations and pharmacokinetics of lidocaine during a 12-h infusion to postoperative horses. A second purpose of the study was to evaluate the in vitro plasma protein binding of lidocaine in equine plasma. Lidocaine hydrochloride was administered as a loading dose, 1.3 mg/kg over 15 min, then by a constant rate IV infusion, 50 microg/kg/min to six postoperativ...
Scheidhacker M, Bender W, Vaitl P.After describing horse-riding as a facility in managing mentally ill patients, a program for chronic schizophrenic in-patients is presented. Clinical experience with this program and also results of a controlled study are reported. The therapeutic value and slope for horse-riding are discussed in relation to different diagnoses.
Muylle E, Van den Hende C, Nuytten J, Deprez P, Vlaminck K, Oyaert W.The concentration of potassium in plasma and in red blood cells was determined in 948 horses. The coefficient of correlation between the two parameters was low. In 436 of these horses, which were clinically healthy, the red blood cell potassium (RBCK+) levels did not fit within a normal distribution curve, but a bimodal distribution was observed with a section point at 90 mmol/litre. In 90 per cent of these normal horses, mean RBCK+ content was 97.5 mmol/litre. In the remaining 10 per cent, mean RBCK+ concentration was 93.8 mmol/litre. A subdivision into a 'low potassium group' and a 'high pot...
Hopster-Iversen C, Hopster K, Staszyk C, Rohn K, Freeman D, Rötting AK.Large intestinal diseases in horses are characterised by inflammation, which could arise from the disease process with some contribution from intestinal manipulation. The effects of the latter are unknown but important to surgeons and could contribute to post operative complications. Objective: To characterise type and degree of intestinal inflammation induced by various mechanical stimuli in the equine ascending colon. Methods: Laparotomy was performed in 12 horses, the left dorsal colon exteriorised and 3 segments randomly exposed to different mechanical manipulations: 1) enterotomy, 2) ente...
Carvalho Seabra J, Hess T, Martinez do Vale M, Spercoski KM, Brooks R, Dittrich JR.Free choice forage could be the best option regarding horses' welfare but can lead to increased body weight (BW), and waste of hay. Automatic box feeders (BF) and slow feeders (SF) decrease food waste, but it is unknown how these affect the horses' time-budget (TB). This study compared the effects of feeding free choice hay (FC), to a SF and an automated BF on the horses' cortisol circadian rhythm (CCR) and behavior by 24-hours continuous behavioral sampling (CBS). The study was designed as a 3 × 3 Latin square design with 15 polo horses divided into 3 groups, for 15 days on each treatment....
Stover KK, Williams SH.In mammals, chewing cycle duration (CCD) increases with various measures of size, scaling with body mass(0.13-0.28) and jaw length(0.55). Proposed explanations for these scaling relationships include the allometry of body size, basal metabolic rate and tooth size, on the one hand, and pendular mechanics treating the jaw as a gravity-driven pendulum, on the other. Little is known, however, about the relationship between CCD and size within species. Recent research in dogs demonstrates altogether different scaling exponents and weaker correlations. This research suggests that breed-specific grow...
Wilkins PA, Dewan-Mix S.The efficacy intravenous plasma to transfer passive immunity to clinically healthy colostrum-deprived and clinically ill foals with failure of passive transfer was investigated. Efficacy of transfer was evaluated by the elevation of serum IgG per gram of IgG administered as a function of body weight. Colostrum deprived healthy foals had a significantly greater increase in serum IgG than did clinically ill foals with failure of passive transfer. Knowledge of the IgG content of plasma to be administered and the health status of a foal with failure of passive transfer should allow more accurate p...
Mitchell SW, Moran RA, Elbourne LDH, Chapman B, Bull M, Muscatello G, Coleman NV.Antimicrobial resistance in bacteria is a threat to both human and animal health. We aimed to understand the impact of domestication and antimicrobial treatment on the types and numbers of resistant bacteria, antibiotic resistance genes (ARGs), and class 1 integrons (C1I) in the equine gut microbiome. Antibiotic-resistant fecal bacteria were isolated from wild horses, healthy farm horses, and horses undergoing veterinary treatment, and isolates (9,083 colonies) were screened by PCR for C1I; these were found at frequencies of 9.8% (vet horses), 0.31% (farm horses), and 0.05% (wild horses). A co...
Valentine BA, Del Piero F, Edwards RB.Intramuscular desmoid tumors (musculoaponeurotic fibromatosis) were discovered in two young adult horses. The tumor in one horse was in the lateral cervical musculature, and that in the second horse occurred in the pectoral musculature. Histopathologic features were similar in both horses and included proliferation of fibroblasts and cells expressing muscle actin (myofibroblasts), with extensive dissecting fibrosis within muscle. These features are similar to those of desmoid tumors in humans, particularly those also known as musculoaponeurotic fibromatosis. Dissection of these lesions reveale...
Oikawa M, Narama I.Two cases of enthesopathy of the radial tuberosity in Thoroughbred racehorses are described. Soft X-ray pictures revealed separated bony fragments at the anterior aspect of the radial tuberosity, resembling the lesions of Osgood-Schlatter disease in children. Osgood-Schlatter lesions result from detachment of a portion of the apophysis of the tibial tuberosity. However, in the affected horses, the detached bony fragments consisted of cortical bone tissue composed of trabeculae with osteons similar to lamellar bone, the main component of the radial tuberosity. Tendon fibrils were inserted into ...
Meyer ND, Bayly WM, Sides RH, Wardrop KJ, Slinker BK.Prolonged equine exercise can cause hypochloraemic alkalosis and hypokalaemia secondary to the loss of hypertonic sweat. Movement of ions in and out of erythrocytes during exercise may help regulate acid-base balance and changes in plasma ion concentrations. The extent to which this happens during prolonged equine exercise has not been reported. Objective: To measure changes in blood gases and major plasma and intraerythrocytic (iRBC) ion concentrations of horses undergoing prolonged submaximal exercise. Methods: Six horses were trotted at ∼ 30% VO2max on a treadmill for 105 min. Arterial ((...
Malhotra DV, Banerjee DP, Gautam OP.The prevalence of Babesia equi infection in north west India was assessed by means of the capillary tube agglutination (CA) test. The particulate antigen used in the test was potent and no cross reaction with other related haemaprotozoa was observed. The serological survey showed that from 323 horses from 3 localities there was an overall incidence of 50.1 per cent. In Haryana the incidence was 38.3 per cent in the 196 horses tested, in Uttar Pradesh it was 47.2 per cent from 72 animals and in Rajasthan it was 96.4 per cent from 55 horses.
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...
