"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.
Kamerling SG, Dequick DJ, Weckman TJ, Tobin T.Sensitive methods for measuring the analgesic, physiological and behavioural effects of opioids in the horse have recently been developed. Fentanyl, a prototypic mu-opiate receptor agonist, has been previously shown to produce a syndrome characterized by marked analgesia and locomotor stimulation as well as tachycardia, tachypnoea and behavioural arousal. To determine whether other opiate receptors mediate some of the actions of the narcotic analgesics in the horse, an agent with activity at kappa- and to lesser extent mu-receptors was studied using a vigorous experimental protocol. Like fenta...
Palmieri G, Panu R, Asole A, Farina V, Sanna L, Gabbi C.The most developed and organized lamina running trough the biceps brachii muscle belly forms a well-marked tendinous intersection connecting the proximal tendon with the distal one. Moreover, the lacertus fibrosus arises from this lamina close to the distal tendon and blends with the fascia of the forearm and joins the extensor carpi radialis muscle. The nerve supply for the biceps tendinous intersection arises from the intramuscular rami of the musculo-cutaneous nerve, whereas the lacertus fibrosus is provided with some cutaneous rami of the same nerve. The biceps brachii tendinous intersecti...
Yamamoto K.Monospecific (MSp-) antisera against E1 and E2 glycoproteins of western equine encephalitis (WEE) virus were prepared and examined for binding activities to whole virions, hemagglutination-inhibition (HI), neutralization (NT) and protection. Both anti-E1 and anti-E2 MSp-Abs protected mice against WEE virus challenge. A competition experiment with monoclonal antibodies showed that these MSp-antisera appear to lack the antibody population for some epitopes involved in viral neutralization.
Bos H, van der Meij GJ, Dik KJ.Bone structure, nutrient canals, form and definition, and a total evaluation of both fore navicular bones were radiologically evaluated in 169 three- and four-year-old Dutch warmblood mares divided into eleven daughter (half sister) groups. On the basis of the 'total evaluation', differences between the three- and four-year-old horses were detectable. Using the 'total evaluation', significant differences were found between daughter groups consisting of three-year-old mares. These differences support the theory that podotrochleosis may be (partly) due to the presence of genetic factors. The pos...
Chowdhury SI, Kubin G, Ludwig H.Out of 30 cases of abortion and perinatal deaths in a Lipizzaner stud in Austria 10 mares died after having shown central nervous system disturbances, ataxias and paralysis. The etiological agent of this "abortion storm" was equine herpesvirus type 1 (EHV-1). The restriction enzyme pattern of the DNA from 5 isolates recovered from fetuses has been analyzed and compared with the known reference strains of EHV-1, -2, -4 and an Austrian vaccine strain. The DNA restriction profiles of the Lipizzaner isolates as well as of the vaccine strain could be identified as being typical of abortigenic strai...
Chamorro CA, de Paz P, Sandoval J, Fernandez JG.The morphological characteristics of bovine and equine gustatory lingual papillae are compared by scanning electron microscopy. The fungiform papillae in the cow have a shape that corresponds to their name, while in the horse, they almost do not emerge from the surface of the tongue. These papillae show taste pores in both species. The vallate papillae, four times larger in the horse than in the cow, show a complex organization of papillae and secondary grooves in the horse. In the cow, they occur single and are surrounded by a thick annular pad of lingual mucosa. Taste pores have been observe...
Köhler H, Oberlojer HG, Schönbauer M.In the ampulla roof of the wave-like extending horse rectum the muscular coat is only weakly developed as a deltoid-shaped tuna muscularis area, thus forming a place of minor resistance. With regard to the degree of development of the muscular coat a rectal ampulla with a stable form and strong muscles can be distinguished from an ampulla with a labile form and weak muscles. The rupture of the intestinal wall in this region in the case of rupture-experiments as well as the frequent occurrence of diverticula reveals this area as being a place of minor resistance which requires extreme caution d...
Tatarov G, Dilovski M.An avirulent immunogenic virus strain mutant of the causative agent of rhinopneumonia was found to cause abortions and respiratory diseases in horses. The mutant was obtained with the use of a virulent strain that induced strongly manifested clinical symptoms of the disease, and was cultured in cell media containing 5-iodine-2-desoxiuridine as an antimetabolite, following a definite pattern. It was found that the mutant completely lost its virulence, however, it retained its immunogenicity. It likewise retained these newly acquired biologic properties with regard to its being stable and irreve...
Holmes JR, Henigan M, Williams RB, Witherington DH.The paper describes five cases of atrial fibrillation detected after racing. In four of them, the arrhythmia disappeared spontaneously within 24 h and they were regarded as paroxysmal in type. In the fifth case, which won its race, the arrhythmia persisted for at least 45 h after racing. It was therefore regarded as an example of persistent atrial fibrillation. It was then treated with quinidine sulphate which restored sinus rhythm. It would seem that paroxysmal atrial fibrillation may be a cause of sudden decrease in racing performance.
Johansson IM, Anlér EL, Bondesson U, Schubert B.Two metabolites of meclofenamic acid have been isolated from equine urine. Both metabolites are found to be monohydroxylated forms of meclofenamic acid by gas chromatography-mass spectrometry after extractive alkylation. The parent drug and the metabolites are separated by reversed-phase liquid chromatography on a Spherisorb ODS column, using methanol-phosphate buffer eluents and UV detection at 280 nm. The structure of the metabolites is discussed on the basis of LC, TLC and GC-MS data.
Eysker M, Mirck MH.The distribution of inhibited early third stage Cyathostominae larvae in different parts of the large intestine of the horse was studied in 20 Shetland ponies necropsied in autumn 1982, 1983 and 1984. The location of the larvae in the large intestinal wall was studied by histological examination of the intestines of the eight ponies from 1984. Inhibited larvae were located predominantly and more or less equally in the caecum and the ventral colon. Generally fewer early L3 were in the dorsal colon. In 1984 a considerable proportion (mean 17%, range 9.7-36.9%) of the inhibited larvae was found i...
De Waal A, Littlejohn A, Potgieter GM, Van der Berg J, Minnaar PI, Smith A.An apparatus was designed to collect four consecutive blood samples from exercising horses. The collection of each sample was controlled by valves activated by radiotelemetry signals transmitted by an observer. Using the device, venous blood samples were collected from ten thoroughbred racehorses before, during and after a 400 m training gallop. Blood glucose increased markedly post-exercise. Both phosphorus and potassium concentrations increased during exercise, decreased post-exercise and recovered to pre-exercise levels within 120 minutes. The system was modified to collect anaerobic sample...
McDonough PL, Shin SJ, Timoney JF.The salmonella serotypes isolated during 1978 to 1983 at the diagnostic and clinical laboratories of the New York State College of Veterinary Medicine from animal sources in New York state were reviewed and compared to earlier data from New York state animals and to national data for both human and animal sources. A total of 255 salmonella strains were studied from the six year period and included 33 serotypes. Salmonella enteritidis ser Typhimurium continued to be the most commonly reported serotype followed by serotype Anatum. Generally serotypes from New York state animals reflected nationa...
Skrabalak DS, Henion JD.Betamethasone and its major unconjugated metabolite, 6-beta-hydroxybetamethasone, were detected in equine urine by thin-layer chromatography and characterized by micro-liquid chromatography/mass spectrometry (micro-LC/MS). Their structures were confirmed by a combination of infrared spectroscopy and nuclear magnetic resonance spectroscopy.
Meinecke B.The present study comprises 31 mares, that showed a permanent unilateral enlargement of the ovary. In 29 patients the ovary in question was removed by a flanc laparotomy in the standing animal. In the histopathologic examination a granulosa cell tumor was diagnosed in 23 cases, a fibroma twice and a teratoma, hematoma, leiomyoma and a cystic ovary each once. Due to the endocrine activity of the granulosa cell tumor, the clinical picture was characterized by changed behaviour and atrophy of the contralateral ovary. Clinically the ovarial blastomas (teratoma, leiomyoma, fibroma) could not be dif...
Whitton DL, Trim CM.Heart block is a relatively common arrhythmia in the adult horse. It may be a normal physiologic phenomenon or it may have pathologic implication. Four foals in which advanced heart block developed during anesthesia were unresponsive to atropine sulfate and supportive treatment alone. Resolution of the heart blocks was achieved after the addition of dopamine hydrochloride to the therapeutic regimen.
Uhlinger C, Johnstone C.A survey was conducted to determine the prevalence of benzimidazole (BZ)-resistant small strongyles in horses in a southeastern Pennsylvania practice. Resistant parasites were found in 291 of 342 horses surveyed. Anthelmintic practices and pasture management factors in use for 3 to 6 years did not correlate with the presence of resistant small strongyles. Benzimidazole-resistant small strongyles were recovered in horses that had been treated alternately with BZ and non-BZ products and in horses receiving BZ products as infrequently as twice a year. However, inasmuch as the horses may have been...
Markel MD, Orsini JA, Gentile DG, Freeman DE, Tulleners EP, Harrison IW.Four horses operated on for left dorsal displacement of the large colon (LDDLC) had major intraoperative or postoperative complications. One horse was euthanatized during surgery because of extensive necrosis of the large colon. Three horses that were discharged after surgical correction of LDDLC were readmitted with signs of abdominal pain between 5 weeks and 13 months after surgery. Two horses had recurrence of LDDLC, and the third horse had an omental adhesion attached to and obstructing the pelvic flexure. The displacements were corrected, the adhesion was broken down, and the horses were ...
Furuoka H, Yamada M, Miyazawa K, Taniyama H, Matsui T.Here were report eosinophilic globular bodies referred to as dense microspheres (DMS), in the brains of normal horse in relation to the ageing process. The characteristic structures of DMS found in the horse were in similar to those previously reported in the human. The DMS were found predominantly in the neuropil of the cerebral cortex, and were shown histochemically to have a proteinaceous content. Electron microscopy showed that the DMS consisted of homogeneous electron-dense material bound by a single membrane and that they were found within the neuronal processes. In addition, immature or...
Steinman A, Kachtan I, Levi O, Shpigel NY.Clostridium botulinum type C is prevalent in Israel and outbreaks recorded in many species, other than horses. Association between levels of anti-BoNT/C antibodies and equine grass sickness (EGS) have been demonstrated but seroprevalence of anti-BoNT/C antibodies in horses has not been reported nor has EGS been reported in Israel. Objective: To determine the seroprevalence of specific anti-BoNT/C antibodies in horses in Israel and to determine whether age, breed and gender, or geographical region of farms are potential risk factors for exposure to BoNT/C. Objective: Anti-BoNT/C antibodies are ...
Marlin DJ, Young LE, McMurphy R, Walsh K, Dixon P.There is evidence that halothane inhibits nitric oxide synthase in vitro, but the effect of intravenous anaesthetic agents is less clear. This study was undertaken to compare the rate of exhaled nitric oxide production (VNO) in spontaneously breathing horses anaesthetized with halothane or an intravenous regimen. Seven adult horses were studied twice in random order. After premedication with romifidine 100 microg kg(-1), anaesthesia was induced with ketamine 2.2 mg kg(-1) and maintained with halothane in oxygen (HA) or by an intravenous infusion of ketamine, guaiphenesin and romifidine (IV). I...
Rivera-Velez A, Huber L, Sinha S, Cohen ND.Rhodococcus equi is a common cause of severe pneumonia in foals. Emergence of macrolide-resistant R. equi isolated from foals and their environment has been reported in the United States. A novel erm(51) gene was recently identified in R. equi in soil from horse farms in Kentucky. Our objective was to determine the effect of the erm(51) gene and associated rpoB mutation on the fitness of multidrug resistant-R. equi (MDR-R. equi) under different nutrient conditions. Bacterial growth curves were generated for 3 MDR-R. equi isolates and 3 wild-type (WTN) R. equi isolates recovered from environmen...
Busse NI, Gonzalez ML, Wagner AL, Johnson SE.Optimal athletic performance requires meeting the energetic demands of the muscle fibers, which are a function of myosin ATPase enzymatic activity. Skeletal muscle with a predominant oxidative metabolism underlies equine athletic success. Sodium butyrate, a short-chain fatty acid, can affect muscle fiber composition in pigs. To determine if a similar scenario exists in horses, 12 adult Thoroughbred geldings (7.4 ± 0.6 yr of age; mean ± SEM) were fed 16 g of calcium butyrate (CB) or an equivalent amount of carrier (CON) daily for 30 d in a crossover design. Middle gluteal muscle biopsies were...
Wright IM, Montesso F, Kidd LJ.This paper describes the clinical and radiological features, surgical techniques used and results obtained in 6 horses with fractures of the tibial tuberosity. The horses were presented between 24 h and 8 weeks following injury. In all 6 cases, the fragments were displaced proximocranially and in 2 of these, there was comminution. Four were treated by open reduction and internal fixation using an AO/ASIF narrow dynamic compression plate and in 2 cases the fragments were removed. All horses returned to full athletic function and remained sound in follow-up times of 17-36 months. Implant removal...
Pasquel SG, Agnew D, Nelson N, Kruger JM, Sonea I, Schott HC.Although the equine renal pelvis and terminal recesses have been described post mortem, little information exists about the endoscopic appearance of these structures in the living horse for guiding ureteropyeloscopy. Objective: To further document the anatomy of the upper urinary collecting system, specifically the renal pelvis and terminal recesses, of the horse. Methods: Descriptive study of cadaver material. Methods: Kidneys were harvested from 10 horses. Magnetic resonance imaging was performed after distension of the renal pelvis with an elastomer casting material, followed by visual insp...
Hummer EV, Soares JHN, Crockett DC, Aguiar AJA, Tran MC, Cronin JN, Brosnan RJ, Braun C, Formenti F.The possibility of accurately and continuously measuring arterial oxygen partial pressure (PaO2 ) in horses may facilitate the management of hypoxaemia during general anaesthesia. Objective: The aim of this study was to evaluate the ability of a novel fibreoptic sensor to measure PaO2 (PaO2Sensor ) continuously and in real time in horses undergoing ventilatory manoeuvres during general anaesthesia. Methods: In vivo experimental study. Methods: Six adult healthy horses were anaesthetised and mechanically ventilated in dorsal recumbency. A fibreoptic sensor was placed in one of the facial arteri...
Ozawa A, Inokuma H, Johke T.The relationship between plasma insulin-like growth factor-I (IGF-I) level and body weight was studied in six breeds of horse. The correlation coefficients between plasma IGF-I and body weight in males and females of 1 year old heavy horses (Percheron and Breton breeds) were 0.62 and 0.12 respectively. The mean plasma IGF-I of males was higher than that of females (p < 0.01). However, the plasma IGF-I levels of heavy horses did not exceed those of light horses (Thoroughbred) or ponies (Shetland and Falabella). These data suggest that IGF-I is at least related to the difference of body weights ...
Ochi A, Nishioka T, Kurimoto S, Kishi D, Ueno T, Nukada T.A 2-year-old male Thoroughbred horse presented with a mass in the maxilla. The focally ulcerated mass, approximately 8 cm in diameter, covered the upper left intermediate and corner incisor teeth (nos. 602 and 603 according to the modified Triadan system) and radiographic examination revealed displacement and lysis of the incisors. Histologically, the tumour was composed of a dense proliferation of spindle-shaped cells and neoplastic odontogenic epithelial cells arranged in island, follicular, plexiform or sheetlike patterns. The spindle-shaped cells were immunopositive for cytokeratins AE1/A...
Woods WE, Weckman T, Wood T, Chang SL, Blake JW, Tobin T.A commercially available radioimmunoassay kit was used to screen for the presence of etorphine in post-race urines from horses racing in Kentucky. Most horse urines contained small amounts of materials which reacted positively in this immunoassay. These materials are apparently endogenous to the horse and were called apparent etorphine equivalents. The levels of these apparent etorphine equivalents in post-race urines from 70 horses were estimated. Their modal level averaged 0.1 ng/ml, the population distribution was log normal, and individual horses showed levels of up to 0.8 ng/ml.
Cunha AP, Bello AC, Leite RC, Bastianetto E, Ribeiro AC, Freitas CM, Oliveira PR.The aim of this study was to verify the efficiency of a strategic control program of Amblyomma cajennense in horses under field conditions. Acaricide treatments were applied at seven days intervals and divided in two series, the first one beginning in April 2004 (eight treatments), and the second one beginning in July 2004 (five treatments), aiming to control larvae and nymphs of the tick. A pyrethroid chemical base cypermethrin 0.015% was used for spraying the horses. There was a reduction of 44.85% in the adults infestation of the tick in the period of October 2004 to March 2005, and 59.74%,...
Pedersoli WM, Fazeli MH, Haddad NS, Ravis WR, Carson RL.Endometrial tissue and blood serum gentamicin (GT) concentrations were determined in 6 ovariectomized pony mares given intrauterine infusions (50 ml of a 5% commercial aqueous solution of GT) each day for 5 consecutive days. The mares were subjected to the following 3 treatments: (1) GT infusion only (trial A, control); (2) progesterone plus GT (trial B, P + G); and (3) estradiol plus GT (trial C, E + G). Endometrial tissue concentrations of GT (micrograms/g) at 24 and 120 hours were significantly higher (P less than 0.05) in trials B (65.54 +/- 15.57 and 100.33 +/- 19.27) and C (73.33 +/- 22....
Klein HJ, Schulze E, Deegen E, Giese W.In 5 horses, 13CO2/12CO2 ratios in expired air were determined using isotope mass spectroscopy to investigate metabolism of naturally occurring [13C]glucose. Oral glucose tolerance tests (OGTT) were performed using maize or beet glucose. Maize has a higher 13C concentration than that of most plants. The 13CO2/12CO2 ratios after OGTT was performed using maize glucose were compared with 13CO2/12CO2 ratios in expired air after OGTT was performed using beet glucose. The ratio also was determined during the period horses were not fed. Using OGTT, all horses were glucose tolerant. The OGTT performed...
Albanese V, Munsterman AS, DeGraves FJ, Hanson RR.To measure intra-abdominal pressure (IAP) in horses that crib and compare it with IAP in horses that do not have this vice. Methods: Cohort study. Methods: Healthy cribbing horses (cribbing cohort, n = 8) and 8 healthy noncribbing horses (noncribbing cohort). Methods: A microsensor catheter was introduced into the peritoneal cavity through the right paralumbar fossa, using local anesthesia, for measurement of IAP. These pressures were recorded in 1-minute intervals for 2 hours, while the horses were standing tied in a stall. IAPs of cribbing horses were compared to the noncribbing cohort...
Graper M, Fischer AT.Practicing at a referral center makes one aware of the necessity for consistent clear communication with the referring veterinarians. The referring veterinarian is ultimately the primary client of the referral center and should be respected as such. Once the necessary care has been provided, the client and horse should be returned to the care of the referring veterinarian. It is important that the referring veterinarian stay involved in the case and communicate if they wish for more or less contact with the referral center.
Hoskinson JJ, Tucker RL, Lillich J, Bertone JJ.While many equine diagnostic imaging procedures can be done in field, some procedures require specialized facilities, equipment or expertise which are generally only available in referral or specialty practices. As client awareness of the availability and advantages of these diagnostic procedures increases, veterinarians are faced with the increasing opportunity to utilize these services to provide optimal patient care. A working knowledge of the value and limitations of these methods is required to help guide veterinarians and clients in the selection of additional, and sometimes costly, diag...
Polzer J, Slater MR.A case-control study was conducted at the Texas Veterinary Medical Center between January 1, 1986 and December 31, 1991. Logistic regression was used to assess age, breed, sex, and seasonality as risk factors for equine laminitis. There were 70 acute cases, 183 chronic cases, and 779 controls. No statistical association was found between age, breed, sex, or seasonality and the diagnosis of acute laminitis. For chronic cases, the estimated odds ratio was statistically significant for age (OR = 1.05, 95% CI (1.02, 1.08)) and for the diagnosis of laminitis in the third quarter of the year (OR = 2...
McDowell KJ, Sharp DC, Grubaugh W.Eight ovariectomized pony mares were used to test the effect of various doses of progesterone (0, 50, 150, 450 mg/day, in oil, i.m., for 10 days) on progesterone and LH in the peripheral circulation, and on total protein and uteroferrin in uterine secretions. Progesterone increased uteroferrin, but there were no differences amongst doses of progesterone. Progesterone treatment decreased LH, and tended to increase total protein. Eighteen ovariectomized mares were given vehicle, oestradiol (10 mg/day, in oil, i.m.), progesterone or progesterone + oestradiol for 28 days. Both the last two steroid...
Cabler P, Geddes LA, Rosborough J.Ultrasonic energy, provided by a commercially available water vaporizer, was used to vaporize methoxyflurane, halothane, and chloroform. The vaporizer was placed directly in the respiratory line, and the anaesthetic liquid was vaporized one drop at a time. Anaesthesia was maintained for periods up to 6 hr in horses, ponies, calves, sheep, dogs, and one pig. This method of vaporizing liquids is applicable to a wide variety of anaesthetics. It is easily controlled, and the same vaporizer can be used with a wide range of sizes of subjects. The vaporizer can be placed directly in the respiratory c...
Mair TS, Stokes CR, Bourne FJ.The immunoglobulin (Ig) content of serum and tracheal lavage fluid was measured in 50 horses suffering from chronic obstructive pulmonary disease (COPD) and 40 control horses. The mean immunoglobulin: albumin ratios of the lavage fluids of both groups were significantly higher than the corresponding values for serum, which indicates significant local production of immunoglobulins in the lower respiratory tract. The IgA: albumin ratio of lavage fluid was significantly higher in diseased compared with normal horses, which implies increased local production of IgA in this disease. The IgG: albumi...
