"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.
Posnett ES, Ambrosio RE.A genomic library of Babesia caballi DNA was constructed in the plasmid vector pUC13. The specificity of the clones for B. caballi was established by the lack of hybridization to Babesia equi, Babesia bovis, Babesia bigemina and equine DNA. Two probes, pBC11 and pBC191, were isolated that could detect 0.25 ng and 0.125 ng of B. caballi DNA, corresponding to a parasitaemia of 0.12% and 0.06% respectively. pBC191 could detect B. caballi parasites in the blood of an experimentally infected horse as well as in naturally infected horses.
Sinha AK, Hendrickson DA, Kannegieter NJ.The initial clinical signs displayed by two horses with head trauma are described and related to the pathology and management of the condition, to illustrate the diversity of signs that may result from similar events. It is suggested that careful repeated neurological investigations are more reliable prognostic indicators in cases of equine head trauma than a reliance on the initial assessment.
Blythe LL, Craig AM, Lassen ED, Rowe KE, Appell LH.Plasma alpha-tocopherol (vitamin E) values were monitored serially in 9 foals sired by a stallion with equine degenerative myeloencephalopathy (EDM) and in 5 age-matched control foals (sired by a clinically normal stallion) raised in the same environment for the first year of life. Clinical evaluation determined that 8 of the 9 foals sired by the stallion with EDM had neurologic deficits consistent with the disease on one or more occasions during the study period, whereas control foals had normal gait. From 6 weeks to 10 months of age, plasma alpha-tocopherol values in foals with signs of EDM ...
Guthrie AJ, Killeen VM, Mülders MS, Grosskopf JF.The ratio of the cardiopulmonary blood volume to stroke volume is called the cardiopulmonary flow index (CPFI). The CPFI can be determined indirectly from the simultaneous recording of a radiocardiogram and an electrocardiogram. The CPFI and cardiac output were measured simultaneously in horses (n = 10) that were diagnosed as having cardiac disease. The diseased subjects were probably all exposed to feed contaminated with the ionophore, salinomycin, and all showed clinical signs indicative of chronic toxic myocarditis. The results obtained from these subjects were compared with those from cont...
den Boon JA, Snijder EJ, Chirnside ED, de Vries AA, Horzinek MC, Spaan WJ.The nucleotide sequence of the genome of equine arteritis virus (EAV) was determined from a set of overlapping cDNA clones and was found to contain eight open reading frames (ORFs). ORFs 2 through 7 are expressed from six 3'-coterminal subgenomic mRNAs, which are transcribed from the 3'-terminal quarter of the viral genome. A number of these ORFs are predicted to encode structural EAV proteins. The organization and expression of the 3' part of the EAV genome are remarkably similar to those of coronaviruses and toroviruses. The 5'-terminal three-quarters of the genome contain the putative EAV p...
Meyers PJ, Varner DD.A mummified fetus was aborted at 284 days of gestation from a Quarter Horse mare with a history of consecutive abortions. The abortion occurred 12 days after administration of supplemental progestogen had been discontinued. Results of a breeding soundness evaluation revealed that this mare had a short uterine body. Other abnormalities were not discovered. This condition may have been responsible for repeated abortions in this mare, and may represent a cause of fetal mummification other than twin pregnancy in mares.
Tulleners EP.A submucosal abscess, located on the dorsal surface of the epiglottis, was diagnosed in 2 Thoroughbred racehorses by use of endoscopy. Both horses had exercise intolerance. One horse had intermittent dorsal displacement of the soft palate, coughed while eating and galloping, and made an abnormal respiratory noise. Both abscesses were drained transendoscopically by use of a contact neodymium:yttrium aluminum garnet laser. Eleven days after surgery, the surgical sites appeared to have healed. Clinical signs resolved permanently, and both horses returned to successful racing careers.
Dziezyc J, Millichamp NJ, Keller CB.The medical records of 12 horses that had cataracts removed by use of phacofragmentation were reviewed. Cataracts were removed from 16 eyes in horses ranging in age from 2 months to 15 years. Complications after surgery included corneal ulcers in 13 eyes, diffuse corneal edema in 5 eyes, and uncontrollable uveitis in 3 eyes. Follow-up information was obtained in all horses from 1 month to 3.5 years after surgery. Visual results were judged good by owners or veterinarians in 10 of the horses.
Grosenbaugh DA, Hood DM, Amoss MS, Williams JD.Epidermal growth factor (EGF) receptors were detected in plasma membrane preparations of equine hoof wall laminar tissue at concentrations comparable to that of equine liver. Scatchard analysis of the equilibrium binding data suggested the presence of two classes of EGF binding sites in most of the controls (plasma membranes from clinically normal horses); a high-affinity class and a more numerous low-affinity class. The dissociation constant of the low-affinity class of EGF-specific receptors (KD = 1 x 10(-9)M) is in reasonable agreement with other values established for the EGF receptor. The...
Hall LW, Aziz HA, Groenendyk J, Keates H, Rex MA.To investigate activity in respiratory muscles, insulated wire electrodes were used to record electromyographic activity in the costal diaphragm and in the intercostal, serratus ventralis, internal abdominal oblique, transversalis and rectus abdominis muscles in conscious horses and in the same animals when anaesthetised. Electromyographic activity was related to respiratory phases as recorded by a stethograph around the chest wall. The costal diaphragm showed tonic and inspiratory activity in both conscious and anaesthetised animals. The principal muscle actively involved in expiration was th...
Ricketts SW, Alonso S.Paired endometrial biopsy samples were taken from 530 subfertile mares, before and after treatment (where indicated) and a period of sexual rest. Prognoses were made after each biopsy (Categories 1A-4A before treatment and Categories 1B-4B after treatment), using histopathological criteria similar to those described by Kenney and Doig (1986). Eighty-seven per cent of the mares were assigned to first biopsy prognosis Category 3A. The second biopsy prognosis produced a more even population distribution (10, 47, 40 and 3 per cent respectively for Category 1B, 2B, 3B and 4B mares). First biopsy Ca...
Riley CB, Yovich JV, Bolton JR.Bilateral hypoplasia of the soft palate and aspiration pneumonia occurred in a Standardbred foal. The filly was presented with a history of illthrift, dyspnoea, coughing and bilateral nasal discharge. Abnormal sounds (crackels and wheezes) were auscultated over all lung fields and the cervical trachea. Endoscopy revealed a shortened soft palate with a uvula-like mass protruding from the free border into the nasopharynx. Mucopurulent material was present in the trachea. Samples obtained by tracheal wash were submitted for cytology, culture and sensitivity testing. Results indicated a septic inf...
McIlwraith CW, Foerner JJ, Davis DM.The technique and results of arthroscopic surgery for the treatment of osteochondritis dissecans in 318 tarsocrural joints in 225 horses are reported. Of the 225 horses, 154 were racehorses or intended for racing. Arthroscopic surgery was an effective technique for treating osteochondritis dissecans of the tarsocrural joint. The overall functional ability and cosmetic appearance of the limbs were excellent. Post surgical follow-up information was obtained for 183 horses, of which 140 (76.5 per cent) raced successfully or performed their intended use following surgery. Of the remaining 43, 11 w...
Tulleners EP.Three basic techniques (and one modified technique) were developed, allowing successful excision of subepiglottic cysts in 10 horses (5 Standardbreds, 4 Thoroughbreds, and 1 Quarter Horse; mean age, 3.5 years) via peroral approach. This approach eliminated the need for laryngotomy or pharyngotomy and reduced postoperative care. None of the cysts redeveloped. Clinical signs of disease before surgery included respiratory noise, exercise intolerance, coughing, and dysphagia and were eliminated in all horses except one that raced successfully, but in which some respiratory noise was detected. Pero...
Williams RB, Clark CG, Young SS.A technique for continuous computerised recording and analysis of the stride of horses on a treadmill is described. Advantages of the system are low cost, the use of normal shoes and the calculation of stride parameters in real time.
Darien BJ, Potempa J, Moore JN, Travis J.Antithrombin-III (AT-III) activity was measured at the time of admission in 46 horses referred with colic. Differences in AT-III activities between animals treated medically or surgically and survivors or non-survivors were compared. The mean AT-III values for the horses treated medically (76.2 per cent), surgical survivors (69.5 per cent) and surgical non-survivors (55.9 per cent) were significantly different from the reference value for healthy adults (92 to 108 per cent). The mean AT-III activity of the survivors was significantly (P less than 0.01) greater than that of the nonsurvivors. Th...
Dorman DC, Haschek WM.Toxicosis attributable to propylene glycol (1,2-propanediol) was suspected in an 8-year-old 450- to 500-kg male Quarter Horse. Clinical signs of toxicosis developed within 15 minutes of the accidental iatrogenic oral administration of 3.8 L of propylene glycol. Clinical signs of toxicosis included salivation, sweating, ataxia, and signs of pain. Additionally, at 24 hours after propylene glycol ingestion, the horse became increasingly atactic, had an abnormal breath odor, developed rapid shallow breathing, and was cyanotic. The horse died of apparent respiratory arrest 28 hours after the propyl...
Browning GF, Chalmers RM, Sale CS, Fitzgerald TA, Snodgrass DR.The homotypic and heterotypic antibody response to rotavirus was determined in three pony mares and their foals. The normal concentrations of anti-rotavirus antibodies in mares' milk and mares' and foals' serum over the first 10 weeks post-partum were measured using IgA, IgG and rotavirus serotype-specific enzyme linked immunosorbent assays. Experimental infection of the foals with serotype 3 equine rotavirus produced a rapid, serotype-specific response which peaked 10 days after infection and a slower heterotypic response which peaked 32 days later. In contrast, vaccination of the mares with ...
Gaughan EM, Nixon AJ, Krook LP, Yeager AE, Mann KA, Mohammed H, Bartel DL.Sodium hyaluronate reduces adhesions after tendon repair in rodents and dogs, and has been used in limited clinical trials in people. To evaluate its effect on tendon healing and adhesion formation in horses and to compare these effects with those of a compound of similar visco-elastic properties, a study was performed in horses, using a model of collagenase injection in the flexor tendons within the digital sheath. Eight clinically normal horses were randomly allotted to 2 groups. Adhesion formation between the deep digital flexor tendon and the tendon sheath at the pastern region was induced...
Milne EM, Doxey DL, Kent JE, Pemberton A.Four acute phase proteins were assayed in the serum of normal horses and those with acute, subacute and chronic grass sickness, colic and inflammatory conditions, in order to investigate their diagnostic value in grass sickness. The grass sickness and inflammation group had a significantly increased haptoglobin concentration (P less than 0.01-P less than 0.001). Orosomucoid was elevated in acute, subacute and chronic grass sickness and inflammation (P less than 0.001, P less than 0.001, P less than 0.05 and P less than 0.05, respectively). Highest concentrations of haptoglobin and orosomucoid ...
Weiland G, Hasslinger MA, Mezger S, Pöllein W.In an investigation period over 8 months the natural course of infection was studied by means of coproscopic and serological methods in 27 mares and 29 foals. The examination of the stool showed in mares, before the beginning of the grazing season, an infection rate of 100% with small and a rate of 7.4% with large strongyles (Str. vulgaris). Serologically the ELISA showed in foals only a distinct increase of antibody activity with the somatic antigen. The mares retained the high IgG-values of activity, which were already found at the beginning of the investigations. Even though the agglutinati...
Lavoie JP, Couture L, Higgins R, Laverty S.Bacterial isolations were reviewed from equine trachea, guttural pouch, uterus, wounds, abscesses, blood, synovial fluid, and abdominal fluid submitted to the Clinical Bacteriology Laboratory of the School of Veterinary Medicine at the University of Montreal for aerobic bacterial culture from 1986 to 1988. Of the 733 samples submitted, 324 (44%) were positive for bacterial growth, and 233 antimicrobial sensitivity tests were performed. Seventy-six percent of all positive samples yielded one bacterial species and two were isolated from 22% of positive samples. Streptococcus zooepidemicus, Esche...
Ullrich E, Selbitz HJ, Schieck R, Friedrich U, Schulz J.Clinical, bacteriological and serological examinations on a 6 years old pony mare were performed. Cytological alterations in the genital tract were also recorded. A cellular reaction was seen after infection with T. equigenitalis. This reaction is an evidence for infection but it is not specific for this organism. Cytological studies should be performed on mares especially in cases of latent infections to complete bacteriological examination and to prevent false positive or negative results.
Edington N, Smyth B, Griffiths L.One of three mares in the last trimester of pregnancy became paraplegic 7 days after experimental infection with EHV-1 and was killed 10 days after infection (d.p.i.). The other two mares aborted foetuses at 12 and 14 d.p.i. In the first mare, virus was detected by immunofluorescence (IIF) and immunoperoxidase (IP) staining in endothelial cells of the endometrium, placenta and umbilical vein, but not in any other foetal tissues. In the experimentally aborted foetuses, and in two other independent field cases of abortions, endothelial cell infection was also detected in the foetuses, both in ma...
Jacob JC, Gastal EL, Gastal MO, Carvalho GR, Beg MA, Ginther OJ.The follicle and hormone aspects of diameter deviation and development of one dominant (>/=28 mm) follicle (1DF) vs two dominant follicles (2DF) were studied in 32 ovulatory follicular waves in mares. Follicles were ranked each day as F1 (largest) to F3. The beginning of deviation was designated day 0 and preceded the first increase in the differences in diameter between F1 and F2 in the 1DF group and between a combination of F1 and F2 vs F3 in the 2DF group. One dominant follicle and 2DF developed in 21 (66%) and 11 (34%) waves, respectively. Double ovulations occurred in only one of the w...
de Graaf-Roelfsema E, Tharasanit T, van Dam KG, Keizer HA, van Breda E, Wijnberg ID, Stout TA, van der Kolk JH.To determine the effects of short-term IV administration of hydrocortisone or equine growth hormone (eGH) or long-term IM administration of eGH to horses on tissue sensitivity to exogenous insulin. Methods: 5 Standardbreds and 4 Dutch Warmblood horses. Methods: The euglycemic-hyperinsulinemic clamp technique was used to examine sensitivity of peripheral tissues to exogenous insulin 24 hours after administration of a single dose of hydrocortisone (0.06 mg/kg), eGH (20 microg/kg), or saline (0.9% NaCl) solution and after long-term administration (11 to 15 days) of eGH to horses. The amounts of m...
Sampaio MU, Galembeck F, Paiva AC, Prado ES.The kinetic constants for horse urinary kallikrein and trypsin hydrolysis of BAEE, TAME, bradykinin methyl ester and bradykinyl-Ser-Val-Gin-Val-Ser were determined. The values of the ratio kcat/Km show that (1) kallikrein is catalytically less efficient than trypsin for all the substrates (2) the three esters are equally good substrates for trypsin while horse urinary kallikrein is 100-fold more effective on bradykinin methyl ester than on the other substrates (3) for both enzymes the ester of bradykinin is a better substrate than the tetradecapeptide.
McKibbin LS, Cheng RS.This study showed that subcutaneous injection of a solution of D-amino acids produced effective analgesia in horses. It is postulated that systemic D-phenylalanine and D-leucine may become one of the safe, effective and nonaddictive drugs for acute and chronic pain treatment. These D-amino acids cause analgesia by presumably preserving brain endorphins. They may bind reversibly to enkephalinases and prevent enzymatic degradation of enkephalins.
Gehring R.The Veterinary Pharmacovigilance Centre received 59 reports of suspected adverse drug reactions during the period January 1998 - February 2001. The number of reports received increased after the establishment of a formal procedure for recording and responding to reports. The number of reports received per species was: dogs 19, cats 15, cattle 7, sheep/ goats 6, chickens 4, pigs 3, horses 2 and giraffe 1. Many different types of adverse reactions were reported, including lack of efficacy, hypersensitivity, inappropriate use of products by non-veterinarians, known adverse effects and adverse eff...
Wilson DC, Corbett AD, Steel C, Pannirselvam R, Bovell DL.The causal factors of equine anhidrosis have not yet been elucidated but defective electrolyte transport mechanisms in the gland are likely to be involved. To investigate this possibility, experiments were performed on cultured equine sweat gland epithelia from five free-sweating UK horses (3 intact males, 2 mares, aged 2-4 years) and from three free-sweating Singapore horses (1 intact male, 2 mares, aged 3-5 years) and three anhidrotic (Singapore) horses (1 intact male, 1 gelding, 1 mare, aged 3-6 years). Cultured cells from each animal were grown on permeable supports and loaded into Ussing ...
Seay SS, Aucoin DP, Tyczkowska KL.A simple, rapid and sensitive high-performance liquid chromatographic procedure has been developed for the determination of ketamine and dehydronorketamine in equine serum. Sample preparation consisted of mixing equal volumes of serum and acetonitrile-phosphoric acid (85%)-water (20:2:78, v/v/v), followed by ultrafiltration through a 10,000 molecular mass cut-off filter. Separation of these two analytes in the ultrafiltrate was accomplished on a reversed-phase phenyl column eluted with methanol-acetonitrile-phosphate buffer solution. Ketamine and dehydronorketamine were detected by a variable ...
The Journal of parasitologyNovember 26, 2004
Volume 90, Issue 5 1027-1033 doi: 10.1645/0022-3395(2004)090[1027:AEOARB]2.0.CO;2
Gupta GD, Lakritz J, Saville WJ, Livingston RS, Dubey JP, Middleton JR, Marsh AE.Sarcocystis neurona is the primary parasite associated with equine protozoal myeloencephalitis (EPM). This is a commonly diagnosed neurological disorder in the Americas that infects the central nervous system of horses. Current serologic assays utilize culture-derived parasites as antigen. This method requires large numbers of parasites to be grown in culture, which is labor intensive and time consuming. Also, a culture-derived whole-parasite preparation contains conserved antigens that could cross-react with antibodies against other Sarcocystis species and members of Sarcocystidae such as Neo...
Crawford AM, Mills JN.Venoms of the tiger snake and brown snake were procoagulant, in vitro, when tested with cat, dog, horse and wallaby plasma. In the absence of calcium and phospholipid the coagulant activity of tiger snake venom was minimal. In contrast, brown snake venom alone had marked procoagulant activity. This activity, however, was enhanced by the presence of calcium and phospholipid. Death adder venom exerted an anticoagulant effect. Apparent species' differences in susceptibility to the coagulant venoms were noted. However, the probable explanation of these differences was attributed to variation in th...
Fawcett JA, Innan H, Tsuchiya T, Sato F.Many studies have reported that advancing age in broodmares has a negative impact on the reproductive performance of horses. However, although the ages at first and last mating vary among broodmares, it is unknown how this variation affects the correlation between age and reproductive performance in mares. Here, in order to examine the effects of the ages at first and last mating, we analyzed all recorded mating events for Thoroughbreds in Japan from 1997 to 2017. We found that the live foal birth rate of mares with a younger age at first mating indeed declined at an earlier age than those wit...
Ikenaga H, Mizuta Y, Ono K, Sawazaki T, Suzuki N, Tomoda I.The placental and plasma cystine aminopeptidase (CAP) in pregnant animals was examined on stability after the treatment with L-methionine, ethylene diamine tetra-acetic acid (EDTA) and heat. Inhibitory effects of these treatments on enzyme activities were different among CAPs from the animal species, however, significant correlation in those effects between placental and plasma CAPs was observed. These results suggested that plasma CAP might reflect placental CAP and seemed to be available for estimating maternal gestational conditions.
Jalim SL, McKinnon AO.To evaluate the fertility of mares bred at various intervals relative to surgical management of rectovaginal fistula (RVF). Methods: Surgical repair of RVF was performed in 28 mares at variable times relative to foaling (30 days to 24 months) and also relative to rebreeding (same cycle or delayed). Postoperative fertility was then evaluated. Results: Two mares were already pregnant at the time of surgery and 20 of 23 mares (87%) that were bred immediately prior to or following surgery conceived from their first service. When mares were bred in the same cycle as surgery, the next cycle followin...
Intemann S, Reckels B, Schubert DC, Wolf P, Kamphues J, Visscher C.Evidence has already been provided that feed-borne mold spores and endotoxins can trigger chronic, non-infectious respiratory disease if inhaled. Furthermore, deficiencies in feed microbiology are suspected to trigger gastrointestinal and liver disorders in horses, but the connection needs further clarification. Most of the previous studies regarding horse feed hygiene focused on forage, whereas research regarding hygienic quality of concentrates is scarce. In the present study, results of reports on hygienic quality of compound feed and cereals for horses were evaluated secondarily. Results i...
Ribeiro RM, Ribeiro DDSF, Cota LO, Carvalho AM, Gobesso AAO, Faleiros RR.This study aimed to compare the use of enzymatic colorimetry and Friedewald's formula for the determination of LDL in horses. A total of 260 samples were used. Direct analysis was performed to determine low-density lipoprotein (LDL), high-density lipoprotein (HDL) cholesterol, triglycerides (TG), and total cholesterol (TC). The LDL level was calculated using the Friedewald equation (LDL= TC-HDL-TG/5). The correlations between the direct LDL analysis and the LDL calculated using the Friedewald formula were determined by Pearson's tests, and the coefficient of determination was also obtained by ...
Thijssen HH, van den Bogaard AE, Wetzel JM, Maes JH, Muller AP.The pharmacokinetics of racemic warfarin were studied in 6 adult horses. After IV administration, the plasma concentration of warfarin showed a biphasic decline in time. Analysis of the data, according to 2-compartment kinetics, revealed the following constants: biological half-life was 13.3 hours, apparent volume of distribution was 0.46 L X kg-1, body clearance was 25.3 ml X hour-1 X kg-1. Warfarin was bound (91.5%) to plasma proteins. Unchanged warfarin was not detected in the urine. Absorption from the gastrointestinal tract was almost complete. Concentrations of warfarin in tissue were ex...
Clayton HM.Six event horses jumped a 1.10 m high table fence 4 times under each of 2 conditions; the rider weight condition involved carrying the weight of the rider and saddle (61 kg), whereas the added weight condition included an additional 18 kg weight cloth. Sagittal view, 60 Hz video recordings were analysed using standard methods. Comparisons between the rider weight and added weight conditions using paired t tests (P<0.05) showed a number of significant differences. In the added weight condition the leading forelimb landed closer to the fence, and there were increases in the maximal extension ...
Aiken GE, Potter GD, Conrad BE, Evans JW.Body weight gains and height at the withers were measured in yearling geldings grazing bermudagrass (Cynodon dactylon [L.] Pers.) pastures with neither energy nor protein feed supplementation at stocking rates of 6.7, 8.0, 9.5 and 12.4 yearlings per hectare. Weekly forage samples were taken to estimate the quantity and quality of available forage. These samples were clipped and separated into three equal lengths to characterize upper, middle and lower thirds of the canopy and to determine relationships between available forage and yearling growth rate. Average daily gain was influenced by stoc...
Ginther OJ, Baldrighi JM, Castro T, Wolf CA, Santos VG.In experiment 1, daily blood samples were available from Days 0 to 20 (Day 0 = ovulation) in mares with an interovulatory interval (IOI, n = 5) and in mares that developed idiopathic persistent corpus luteum (PCL, n = 5). The PCL was confirmed by maintenance of progesterone (P4) concentration until end of the experiment (Day 20). Significant interactions of group and day revealed the novel findings that luteinizing hormone (LH) was lower (P < 0.05) in the PCL group than that in the IOI group on Days 0 to 4, and prolactin was lower (P < 0.05) on Days 1, 4, 6, and 7. In experiment 2, treat...
Müller AC, Büttner K, Röcken M.In postoperative monitoring of synovial structure infection due to limb wounds, early recognition of a recurrence of synovial infection is indispensable to prevent further damage to the affected synovial structure. This study evaluated the role of serum amyloid A (SAA) as a systemic biomarker in disease monitoring and correlated this tool with clinical variables. In this prospective cohort study, 55 horses with acute limb wounds were divided into two groups: those with (group 1, n = 26) or without (group 2, n = 29) a diagnosis of synovial structure penetration. SAA, lameness and body tempe...