Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
Gilbert RO.Luteolysis with subsequent shortening of diestrus has been reported to follow equine endometrial biopsy performed early in the luteal phase of the estrous cycle, but a comprehensive study of the effect of endometrial biopsy on cycle length at different times of the cycle has not been reported. In this study, endometrial biopsies were obtained from four different pony mares on each of Days 0, 4, 8, 12, 16 and 20 after ovulation as determined by serial palpation per rectum. Compared with control cycles in the same mares, the ovulatory interval was shortened in mares from which biopsies were obta...
Kobluk CN, Ducharme NG, Lumsden JH, Pascoe PJ, Livesey MA, Hurtig M, Horney FD, Arighi M.From May 1, 1983 to April 1, 1985, 142 operations were performed on horses with signs of acute abdominal pain (colic), using a ventral midline incision. Seventy-eight horses lived for at least 15 days after surgery or had acute dehiscence and were included in the study. Seventy horses had surgery once, and 8 horses had surgery 2 or more times. Six-month follow-up evaluation was obtained for 66 horses that had 1 surgery and for 6 horses that had multiple surgeries. Incisional complications included drainage (including infection), acute dehiscence, hernia, and suture sinus formation. The effects...
Turner AS, Tucker CM.A randomised double-blind clinical trial of 28 horses was undertaken to evaluate the efficacy of isoxsuprine hydrochloride at four different doses:- 0.0 mg/kg bodyweight (bwt) (placebo), 0.6 mg/kg bwt, 1.2 mg/kg bwt and 1.8 mg/kg bwt for treatment of navicular disease. The results showed that horses treated with isoxsuprine hydrochloride (N = 22) responded significantly with respect to clinical assessment score (P less than 0.01) when compared with the control group (N = 6). Furthermore, there were no dose-related differences in the responses of the horses treated with increasing levels of iso...
Freeman DE, Ferrante PL, Kronfeld DS, Chalupa W.A D-xylose absorption test was conducted on 4 healthy mares deprived of food for 12, 36, 72, and 96 hours before the test, with a 13- to 15-day adjustment period between each test. Maximal plasma concentrations after 72 and 96 hours of food deprivation were approximately 36% lower than those obtained after the 12- and 36-hour periods (P = 0.0001). Absorption curves were flatter and the decrease in plasma concentration was slower after the 72- and 96-hour periods of food deprivation. The rate of D-xylose absorption (P = 0.0108) and the initial rate of urinary excretion (P = 0.0117) were slower ...
Bertone AL, VanSoest PJ, Johnson D, Ralston SL, Stashak TS.Fecal excretion of a particulate marker, ytterbium (Yb), was evaluated in 9 horses before surgery and 3 weeks, 3 months, and 6 months (4 trials) after sham-operation (group 1; n = 3) or extensive large colon resection (group 2; n = 6). Fecal excretion curves of total Yb excretion, loge Yb excretion, % Yb excretion, loge % Yb excretion, and cumulative % Yb excretion were evaluated, and kinetic analysis was performed on the loge Yb excretion curves to detect mixing pools and to calculate the fractional rate of particulate passage, turnover rate, and pool size. Calculations were performed to dete...
Adams JG, Trim CM.Five horses were anaesthetised twice with thiopentone sodium, guaifenesin and halothane. The second anaesthesia was 16 days after the first and two days following oral administration of trichlorfon. Heart rate, carotid arterial, pulmonary arterial and right atrial pressures, cardiac output and blood temperature were measured every 15 minutes for 120 minutes. Heart rate, carotid arterial pressure and cardiac output were similar on both occasions. Pulmonary arterial and right atrial pressures were highest during anaesthesia after treatment with trichlorfon when compared with values obtained befo...
Hamada T, Watanabe G, Kokuho T, Taya K, Sasamoto S, Hasegawa Y, Miyamoto K, Igarashi M.A sensitive radioimmunoassay (RIA) for the determination of inhibin in peripheral plasma and tissue homogenates of different species has been developed using antisera to partially purified bovine follicular fluid (bFF) inhibin and 125I-labelled bFF 32 kDa inhibin. Antisera were produced by immunization of rabbits with partially purified bFF inhibin prepared by immunoaffinity chromatography. Increasing doses of a high titre antiserum could neutralize the suppressing effect of bFF, porcine follicular fluid and rat ovarian homogenate on FSH secretion from rat anterior pituitary cells in culture. ...
Gray WL, Yalamanchili R, Raengsakulrach B, Baumann RP, Staczek J, O'Callaghan DJ.Equine herpesvirus type 1 (EHV-1) preparations enriched in defective interfering particles (DIPs) have previously been demonstrated to mediate the coestablishment of persistent infection and oncogenic transformation in primary hamster embryo fibroblasts. In this study, it was demonstrated that infection of a rabbit kidney (RK) cell line with EHV-1 DIP-enriched preparations also results in the establishment of persistent infection. Viral transcription was characterized in RK cells infected with DIP-enriched stocks and compared to viral transcription in RK cells infected with standard (STD) EHV-...
Bertone AL, Schneiter HL, Turner AS, Shoemaker RS.Two mares with multiple carpal bone fractures, malarticulation and degenerative joint disease were successfully treated with unilateral arthrodeses of the antebrachiocarpal, middle carpal, and carpometacarpal joints. Arthrodesis was achieved by removal of articular cartilage, autogenous cancellous bone graft, and double dynamic compression plating. In one horse, wedge ostectomy corrected the severe, acquired angular limb deformity. External coaptation supplemented the internal fixation. Postoperative complications were limited to cast sores that healed with treatment, although protracted in on...
Lochner F, Sangiah S, Burrows G, Shawley R, McNew R, Walker J.The effect of allopurinol pretreatment 12 hours before an intraperitoneal challenge with a sublethal dose of Escherichia coli endotoxin (50 micrograms kg-1) was evaluated in 18 horses. The horses were divided among three equal groups: 1-endotoxin alone; 2-5 mg allopurinol kg-1 bodyweight plus endotoxin; and 3-50 mg allopurinol kg-1 bodyweight plus endotoxin. A variety of evaluation parameters were used. No differences among the groups were noted in rectal temperature, heart rate, respiration rate, haematological values, blood PaO2, blood PaCO2, blood pH or blood bicarbonate. Significant (P les...
Grundy FJ, Baumann RP, O'Callaghan DJ.The immediate early (IE) proteins of herpesviruses are important regulatory factors which control the expression of genes at the transcriptional level. We report the DNA sequence of the immediate early gene of the alphaherpesvirus equine herpesvirus type 1 (EHV-1). This sequence is shown to be extremely rich in guanine and cytosine, resulting in a highly biased codon usage. The IE gene region possesses 38 open reading frames (ORFs) greater than 300 bp in length, 11 of which have coding regions of at least 100 amino acids (aa) following potential translation initiator codons. The largest ORF co...
Detilleux PG, Cheville NF, Sheahan BJ.Tissues from subcutaneous lymphosarcomas and regional lymph nodes were examined by light and electron microscopy and by lectin histochemistry. Tumors were composed of two major cell types: small lymphocytes with few organelles and pleomorphic histiocytic cells with undulant surfaces, large numbers of cytoplasmic vacuoles, and many mitochondria with large crystalline inclusions. A large gram-positive coryneform bacterium was isolated from tumor nodules but was not identified morphologically in tumor tissues. Evaluation of sections of tumors with lectins as histochemical probes revealed three st...
Ball BA, Altschul M, Freeman KP, Hillman RB.Trophoblastic vesicles have been used to study early embryonic development and maternal recognition of pregnancy in domestic animals. The purpose of this study was to characterize the formation of trophoblastic vesicles from Day-12 to Day-16 equine conceptuses. Conceptuses (n = 19) were collected nonsurgically from mares, the capsule was removed, and the conceptus (trophoblast and inner cell mass) was dissected into 2- to 4-mm fragments. Conceptus fragments were cultured in either Ham's F10 (HF10) or Minimum Essential Media (MEM) with 10% fetal bovine serum (FBS) in 24-well plates. Plates were...
Byars TD, Simpson JS, Divers TJ, Shiner KA, Rantanen NW.Percutaneous nephrostomy was used to provide urine output in a 3-year-old Thoroughbred filly with azotemia and obstructive ureterolithiasis. Previous left ureteral surgery had failed to provide clinical improvement, and the filly became more azotemic. Nephrostomy was performed in the standing patient, with ultrasonographic guidance and local anesthesia. Continuing IV fluid therapy and diuresis through the nephrostomy tube resulted in a decrease in clinical signs of azotemia. However, the filly developed a cecal impaction, which ruptured during surgery because of colic, and was euthanatized.
Norman WM, Williams R, Dodman NH, Kraus AE.After surgery, high intramuscular pressures were measured in a horse with clinical signs of postanesthetic myopathy that developed following a 2.25-hour surgical procedure. In the postoperative period, tests for muscular and neurologic integrity were made, including measurement of intracompartmental muscle pressure.
Meagher DM, Aldrete AV.Lateral luxation of the superficial digital flexor tendon from the calcaneal tuber occurs in horses as a result of tearing or rupture of the medial retinaculum of the tendon. This report describes the repair of this condition in 2 Thoroughbred race horses, using a surgical technique in which 2 cancellous bone screws were placed in the calcaneus lateral to the tendon, along with suturing the medial retinaculum.
Belknap JK, Moore JN.The records of 71 horses with small intestinal disorders requiring surgical correction were disorders requiring surgical correction were reviewed to compare the prevalence of laminitis in those horses treated prophylactically with heparin and the prevalence of horses not treated with heparin. The prevalence of laminitis was 13% (9/71), and there was no significant difference (P less than 0.05) in the prevalence of laminitis between the 2 groups. The lack of significant benefit after treatment with heparin indicates that further work needs to be done on the equine coagulation system before hepa...
Vanhaesebroeck B, Grooten J, Fiers W.Using a model of local lymph node (LN) immunization, we investigated the effect of in vivo Ir on the generation of lymphokine-activated killer (LAK) cells or their precursors. Ag used for immunization were SRBC, horse RBC, OVA, keyhole limpet hemocyanin, or CFA. Ag-draining LN, in the acute phase of the Ir, did not contain detectable LAK effector activity, nor an enhanced NK activity. After culture for 3 to 5 days in the absence of exogenously added IL-2, immunized LN cells developed a spontaneous LAK-like cytotoxicity. This activity represented a substantial fraction of the IL-2-generated LAK...
Milne EM, Pogson DM, Else RW, Rowland AC.One case of caecocaecal intussusception (case 1) and one case of caecocolic intussusception (case 2) in ponies are described. Case 1 showed mild abdominal discomfort for seven days followed by sudden death whereas case 2 showed continuous moderate pain for three weeks. At post mortem examination, case 1 showed intussusception of the base of the caecum into the body whereas in case 2, the entire caecum had invaginated into the right ventral colon. Histopathological examination showed that the lesions in both animals had been present for a long time.
Taylor MA, Hunt KR.The term 'anthelmintic drug resistance' describes the heritable ability of some nematode parasites to survive treatment with anthelmintic drugs at the recommended therapeutic dose levels. Genes for resistance appear to be present in many of the important pathogenic nematodes of ruminants and horses. Under intensive management systems, where heavy reliance is placed on anthelmintic drugs for worm control, the selection of resistant genotypes may result in increased reports of the drugs failing to control the nematode populations against which they are aimed. Anthelmintic resistance has been rep...
Foster CV, Harris RC, Pouret EJ.After an oral dose of 10 g of L-carnitine the plasma concentrations of free and total carnitine increased in five yearling thoroughbred horses, reaching a peak two to four hours after administration, but in two horses there was no increase. In the five which responded, the mean (+/- sd) peak increase in total carnitine concentration was 15.1 +/- 6.9 mumol/litre from a predose mean of 18.8 +/- 3.4 mumol/litre, and the mean peak increase in free carnitine concentration was 13.5 +/- 3.1 mumol/litre from a pre-dose mean concentration of 12.5 +/- 2.2 mumol/litre. These changes were similar to those...
Dodman NH, Lehr JL, Spaulding GL, Gavriely N.Three sheep, a foal, a pony, and a calf were anesthetized and ventilated for short periods, using a high-frequency oscillatory ventilator. The efficiency of CO2 elimination was characterized at various oscillatory frequencies (50 to 30 Hz) and various tidal volumes, although the tidal volume used was always less than the measured dead space of the animal. In general, increasing either the oscillatory frequency or tidal volume increased CO2 elimination, but increasing the tidal volume had more effect. The relationship between these 3 variables was best described by a power law equation. Ventila...
Westerduin FE, Lankveld DP, van der Velden MA, Back W, Sloet van Oldruitenborgh-Oosterbaan MM.A 14-year-old Arabian cross-bred gelding was referred to the University Clinic because of mild, recurrent signs of colic for 5 days. The pony showed icteric mucous membranes, haemolytic blood, and dark coloured urine. Internal examination did not give a clear diagnosis. Unidentified intra-abdominal strands were found and haemorrhagic abdominocentesis led to the decision to perform an exploratory laparatomy. An extremely enlarged spleen was the sole finding. A splenal biopsy sample was taken and surgery was completed. The pony remained colicky, so the spleen was examined by ultrasonography. Aft...
Duarte PC, Paz CFR, Oliveira APL, Maróstica TP, Cota LO, Faleiros RR.To investigate the nociceptive and clinical effects of buffering a lidocaine-epinephrine solution with sodium bicarbonate in caudal epidural block in mares. Methods: Prospective randomized controlled trial. Methods: Six mixed-breed mares weighing 350-440 kg. Methods: Each animal was administered two caudal epidural injections, 72 hours apart, using different solutions prepared immediately before injection. The control solution was 7 mL 2% lidocaine hydrochloride with epinephrine hemitartrate (1:200,000) added to 3 mL sterile water for injection (pH 2.9). The alkalinized solution was 7 mL o...
West HJ.Single intravenous injections of bromosulphthalein (BSP) were given to horses and the change in plasma concentration of BSP with time was analysed by computer to obtain the proportionality transfer constants 'a', 'h' and 'b'. No age, weight or sex differences in BSP clearance were found in normal horses. The technique was non-invasive, repeatable and suitable for conscious animals. The measurement of the transfer constants 'a', 'h' and 'b', helped to provide an accurate guide to diagnosis and prognosis of liver disease.
Münzer B, Lubczyk B.Ultrasonography in veterinary practice represents a method that nowadays is a approved component of the examination of small and large animals. Although sometimes more difficult than in small animals, ultrasonography can be often useful in horses. In the present report two cases demonstrate the possibility of sonography in the diagnostic of foreign bodies in soft tissues in horses.
Lacombe VA, Hinchcliff KW, Kohn CW, Reed SM, Taylor LE.Exercise depletes muscle glycogen stores, which could subsequently impair performance. Muscle glycogen replenishment is determined by substrate availability. Objective: To study the effects of feeding meals of varying glycaemic responses on blood concentrations of substrates used for glycogenesis in horses with exercise-induced glycogen depletion. Methods: In a 3-way crossover study, 7 horses received each of 3 isocaloric diets for 72 h after undergoing glycogen-depleting exercise: 1) a high soluble-carbohydrate diet, which induced a high-glycaemic (HGI) response; 2 and 3) a low soluble-carboh...
Kowalik S, Kedzierski W.The effect of interval vs. continuous exercise on plasma leptin and ghrelin concentration in young Standardbred horses was studied. The experiment was conducted on 27 trotters, in the age between 2 and 3 years. They were divided into two groups according to the type of exercise. Blood samples were collected through jugular venipuncture in the following experimental conditions: at rest, immediately after exercise and 30 minutes after the end of the effort. Plasma leptin and ghrelin concentrations were determined using RIA tests. The continuous exercise induced an increase in plasma leptin conce...
King SS, Evans JW.Follicular growth, circulating estradiol concentrations and endometrial prostaglandin F2 alpha (PGF2 alpha) production were measured to determine whether there is an interrelationship among these factors associated with luteolysis. Follicular growth was monitored by rectal palpation every other day during diestrus in 16 mares. Plasma estradiol was determined for daily samples during all estrous cycles. Endometrial tissue was removed for PGF2 alpha analysis by radioimmunoassay on d 10, 12, 14 or 16 during several normal cycles and after d 30 during spontaneously prolonged cycles. Circulating es...
Maddison JE.Seventy-seven reports of suspected adverse drug reactions (ADRs) were received by the Adverse Drug Reaction Subcommittee (ADRSc) of the Australian Veterinary Association from April 1993 to December 1994 inclusive. The number of reports received/number of animals involved per species were: dogs (32/44), cats (18/31), horses (17/48), and cattle (10/21). Of these, 49 (64%) were classified as definite ADRs and 9 (12%) as probable ADRs. In 11 (14%) reports an ADR could not be substantiated or there was insufficient information available to make a decision. Eight reports were not classified because ...
Gross DK, Stover SM, Hill AE, Gardner IA.To assess the accuracy and reliability of a visual method of evaluating horseshoe characteristics. Methods: 1,199 Thoroughbred racehorses. Methods: Characteristics of 1 forelimb horseshoe were visually assessed on horses immediately prior to racing by 5 field observers at 5 major racetracks in California. Characteristics evaluated included horseshoe type; toe grab height; and the presence of a rim, pad, and heel traction devices. Sensitivity and specificity for observer assessment of horseshoe characteristics were calculated by comparing observer assessments to a postmortem laboratory standard...
Prado Silva RH, Carneiro de Rezende AS, Ferreira WM, Bastianetto E, Mello MM, Pereira de Abreu A, Farinelli F, Colares de Araújo Moreira D....Weanlings undergo rapid body development in the first year of life and, in this period, are more susceptible to helminth infection that can impair their growth. The objective of this study was to compare the apparent digestibility of nutrients, blood parameters, and body development of deworming and not deworming weanlings. Fourteen Mangalarga Marchador weanling colts, on a farm in Northern Minas Gerais, Brazil, were divided into two groups: dewormed (D) and not dewormed (ND) groups. The weanlings were kept separately for 3 months in two pastures of Cynodon nlemfuensis cv. African Star Grass....
Sohrabi Haghdoost I, Zakarian B.THE results of a 20 year retrospective study of the tumours diagnosed in all equine cases referred to the Faculty of Veterinary Medicine, University of Teheran, for surgical treatment or post mortem examination are reported here.
Biedrzycki AH, Grant BD, Nemke B, Markel MD, Morello SL.To describe a technique for surgical placement of a modified kerf-cut cylinder for the purpose of arthrodesis across the equine centrodistal and tarsometatarsal joints. Methods: Each horse (n = 4) underwent unilateral placement of a single kerf-cut cylinder spanning the centrodistal and tarsometatarsal joints with the placement of an autologous cancellous bone graft. Horses were evaluated via lameness examination and radiography postoperatively and euthanatization of each horse was performed at four different time points up to 12 weeks post-surgery to evaluate for lameness, implant stability a...
Chan GHM, Tang W, Curl P, Lin Y, Wan TSM, Ho ENM.Arsenic can be easily found in our surrounding environment. Because of its ubiquitous nature, horse urine and blood invariably contain low levels of arsenic. Nevertheless, inorganic arsenic, despite its general use as a tonic for horses, is an effective doping agent having a deleterious effect because of its ability to induce gastroenteritis. The misuse of arsenic in horseracing has been controlled by an international urinary threshold of total arsenic at 0.3 μg/mL. However, an equivalent threshold for total arsenic in plasma is yet to be established. In this study, an inductively coupled pla...
Littlejohn A, Virlas D.Five doses of sodium cacodylate (194 mg) were administered intravenously to two horses at two-day intervals. The arsenic content of daily urine samples was determined for five days after the final dose, by which time urinary arsenic concentrations were close to those of control samples. It was considered that these results reflected a common property of organic arsenicals viz. more rapid excretion by mammals than is the case with inorganic arsenic compounds.
Stadler P, van Amstel SR.The results of a study conducted to determine the clinical changes in 4 experimentally-induced cases of endotoxaemia in the horse are reported on. Endotoxaemia was induced by injecting commercially available E. coli 055:B5 lipopolysaccharide intravenously at a dose of 1 microgram kg-1. The parameters that were monitored include general behaviour, rectal temperature, heart rate, respiratory rate and quality, pulse quality, mucous membrane colour, capillary refill time, appearance of the faeces and the presence of laminitis. Increases in rectal temperature, respiratory and heart rate, capillary ...
Cutler C, Viljanto M, Taylor P, Habershon-Butcher J, Muir T, Biddle S, Van Eenoo P.AC-262536 is one of a number of selective androgen receptor modulators that are being developed by the pharmaceutical industry for treatment of a range of clinical conditions including androgen replacement therapy. Though not available therapeutically, selective androgen receptor modulators are widely available to purchase online as (illegal) supplement products. The growth- and bone-promoting effects, along with fewer associated negative side effects compared with anabolic-androgenic steroids, make these compounds a significant threat with regard to doping control in sport. The aim of this st...
Roberts MC, Norman P.The absorption of d-xylose forms the basis of a useful screening test in the investigation of small intestinal disorders in the horse. A comparison has been made of different assay methods and there was no significant difference between the results obtained with the parabromoaniline (PBA) method or the ferric chloride-orcinol (FCO) method. The orthotoluidine method was unsatisfactory. The anticoagulant agent did not affect the test. A dose of 0.5 g commercial grade xylose/kg body weight as a 10 per cent solution given by stomach tube, produced a peak plasma xylose level after 90 min and should...