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.
Markel MD, Wheat JD, Jones K.The medical records of 10 horses with invasive neoplasms of the penis, prepuce, and/or superficial inguinal lymph nodes in which treatment involved en bloc resection and penile retroversion were reviewed. All were geldings and ranged in age from 12 to 25 years (mean, 19 years). Evaluation of biopsy specimens obtained before surgery confirmed lymphosarcoma in 1 horse and squamous cell carcinoma in 9 horses. Typical history included swelling, ulceration, and abscessation of the penis and prepuce and large superficial inguinal lymph nodes. Complications after surgery included dehiscence of the ur...
Wright JA, Hodson NP.Lesions in a wide range of cranial nuclei are described in 11 horses with grass sickness. Similar changes were seen in one horse with laminitis, but not in control animals. It is suggested that such lesions are non-specific in nature.
Koblik PD, O'Brien TR, Coyne CP.The effect of dorsopalmar projection obliquity on calculation of distal phalangeal rotation (DPR) angle was determined in 8 feet obtained from 5 horses that had been euthanatized because of laminitis. A true lateromedial view of each foot served as a reference, with additional views taken at 5, 10, 15, and 20 degrees of x-ray tube head rotation in both a dorsal and in a palmar direction. Projection obliquity resulted in consistent underestimation of DPR angle. Where projection obliquity exceeded 10 degrees, there were significant (P less than 0.05) differences in DPR angle. The magnitude of un...
Bohanon TC.An 8-cm compressed mass of dry cracked corn was found obstructing the duodenum of a horse with signs of colic. The mass was manipulated aborally and removed through jejunal enterotomy. The horse recovered and the impaction did not recur.
Rose RJ, Hodgson DR, Kelso TB, McCutcheon LJ, Reid TA, Bayly WM, Gollnick PD.This study determined maximal O2 uptake (VO2max), maximal O2 deficit, and O2 debt in the Thoroughbred racehorse exercising on an inclined treadmill. In eight horses the O2 uptake (VO2) vs. speed relationship was linear until 10 m/s and VO2max values ranged from 131 to 153 ml.kg-1.min-1. Six of these horses then exercised at 120% of their VO2max until exhaustion. VO2, CO2 production (VCO2), and plasma lactate (La) were measured before and during exercise and through 60 min of recovery. Muscle biopsies were collected before and at 0.25, 0.5, 1, 1.5, 2, 5, 10, 15, 20, 40, and 60 min after exercis...
Ross MW, Stephens PR, Reimer JM.A 9-year-old pregnant Standardbred broodmare was evaluated for signs of mild abdominal pain, failure to defecate, and mild abdominal distention. Rectal examination revealed the leading edge of a small colon intussusception, and peritoneal fluid analysis indicated suppurative peritonitis. Surgical management, including reduction of the intussusception and small colon resection with end-to-end anastomosis, resulted in successful outcome (1-year follow-up evaluation). Postoperative complications including dehiscence of the ventral midline surgical incision and simple obstruction at the anastomosi...
McCarthy RN, Hutchins DR.A retrospective analysis of 74 cases that underwent surgery for colic was undertaken to determine short and long term survival rates and the incidence of post-operative complications. In 28 cases colic was related to small intestinal lesions and in 46 cases to large intestinal lesions. Pre-operative packed cell volume and heart rate were found to be inversely related to short-term survival. Twenty-five horses (34%) recovered from surgery and were discharged. Of 18 of these cases with available histories, 6 subsequently had one or more episodes of colic since surgery of which 5 eventually died ...
Humber KA.After becoming entangled in safety lines and being submerged in a chlorinated swimming pool, a 2-year-old Thoroughbred gelding was evaluated and treated successfully. Treatment included antimicrobial agents, anti-inflammatory drugs, bronchodilators, diuretics, humidified oxygen, and surfactant transplant. The results of follow-up examination of the gelding 120 days after hospitalization were normal.
Firth EC, Schamhardt HC, Hartman W.Two to 7 days after birth, 9 foals were anesthetized, and strain gauges were applied to lateral and medial aspects of the third metacarpal bone of the left forelimb. In 5 of these foals, strain gauges also were applied to the radius of the left forelimb. Four to 6 days later, foals were walked (5 sets of 10 to 20 strides), and compressive and tensile strains in the bone beneath strain gauges were recorded on paper and diskette. After recording base-line data, a wedge was fitted to the hoof of the limb with the strain gauges, in such a way that the lateral bearing surface was raised, and strain...
Koblik PD, Hornof WJ, Seeherman HJ.Review of 121 bone scintigrams obtained on racing Thoroughbred horses with clinical histories indicative of forelimb lameness revealed 3 scintigraphic patterns of stress-induced trauma to the dorsal cortex of the third metacarpal bone: (1) focal, intense uptake associated with recent stress fracture; (2) regional uptake of varying intensity or a mixed pattern of uptake associated with chronic stress fracture; and (3) diffuse, mild to moderate uptake associated with periostitis (bucked shins). The latter scintigraphic pattern appeared to be an exaggerated manifestation of the normal remodeling ...
Markel MD, Meagher DM, Richardson DW.Colopexy of the left ventral colon to the abdominal wall was performed in 4 horses with recurrence of large-colon displacement or volvulus. Horses were discharged between 5 and 27 days after surgery. At follow-up evaluation (mean, 10.5 months; range, 7 to 13 months) of the horses, none had recurrence of signs of abdominal pain, and all had normal body weight. Three horses were exercised regularly; signs of abdominal pain were not observed.
Songer JG, Beckenbach K, Marshall MM, Olson GB, Kelley L.Isolates (n = 94) of Corynebacterium pseudotuberculosis were obtained from sheep, goats, horses, and cattle from various parts of the world. The isolates were characterized biochemically and by restriction endonuclease analysis of DNA. We found near homogeneity in the ability of isolates to ferment carbohydrates and to produce urease. All isolates produced phospholipase D and catalase. The ability of isolates from horses to reduce nitrate, the inability of isolates from sheep and goats to do so, and the correlation of this characteristic with results of restriction endonuclease analyses confir...
Kloppe LH, Varner DD, Elmore RG, Bretzlaff KN, Shull JW.A breeding trial was conducted to evaluate the effect of insemination timing on the fertility of mares bred with frozen/thawed equine semen. One stallion and 60 reproductively sound, estrous-synchronized mares were included in the study. Mares were assigned to one of three groups (n = 20): 1) insemination with fresh semen every other day during estrus from detection of a 35-mm follicle until ovulation, 2) insemination with frozen/thawed semen every day during estrus from detection of a 35-mm follicle until ovulation or 3) insemination with frozen/thawed semen once, within 6 h after ovulation. ...
Garza F, Thompson DL, Mitchell PS, Wiest JJ.Five lighthorse mares were actively immunized against gonadotropin releasing hormone (GnRH) conjugated to bovine serum albumin (BSA) to study the involvement of GnRH in luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion following ovariectomy (OVX) and after administration of testosterone propionate (TP). Five mares immunized against BSA served as controls. Immunizations were started on November 1, and OVX was performed in June (d 1). All mares were treated with TP from d 50 to 59 after OVX. On the day of OVX, concentrations of LH were lower (P less than .05) in GnRH-immu...
Murray MJ, Ball MM, Parker GA.A 3-month-old foal with a history of persistent fever and leukocytosis was found to have pneumonia, ulceration of the squamous portion of the stomach, and dilatation of the distal portion of the esophagus. The foal was euthanatized and necropsied. The distal portion of the esophagus was severely dilated, and there was severe ulceration and mural thickening of the stomach at the cardia. Because of the severe gastric ulceration and mural thickening, the gastroesophageal junction was fixed in an open position, permitting gastroesophageal reflux. The megaesophagus and pneumonia were considered to ...
Sundquist B, Lövgren K, Morein B.A monovalent experimental ISCOM vaccine has been prepared with the envelope glycoproteins haemagglutinin and neuraminidase of the equine virus strain A/Solvalla/79 (H3N8). In vaccination trials on BALB/c mice the ISCOM vaccine induced more than ten times higher serum antibody titres measured in ELISA than a corresponding experimental micelle vaccine. Similarly, in guinea-pigs the ISCOMs induced about tenfold higher haemagglutination inhibition (HI) and neuraminidase inhibition (NI) titres than a micelle vaccine or a conventional killed influenza whole virus vaccine. Horses vaccinated with a di...
Oftedal OT, Jenness R.Milk samples of four species of wild equids (onager, Equus hemionus onager; mountain zebra, E. zebra hartmannae; plains zebra, E. burchelli; Przewalski horse, E. caballus przewalskii) and two domesticated equids (ass, E. asinus; pony, E. caballus) were analysed. At mid to late lactation the milks of all species were very similar, containing on average 10-12% total solids, 1-2% fat, 1.6-1.8% true protein, 6-7% 'lactose', 0.3-0.5% ash, 0.08-0.12% calcium, 0.04-0.07% phosphorus and a calculated energy content of 2.0-2.4 kJ/g. Milk samples collected in the first 2 weeks after birth showed elevated...
Kobluk CN, Smith DF.An intramural hematoma involving a 40-cm segment of the distal portion of the jejunum caused intestinal obstruction and colic in a mature mare. The involved intestine was resected, and an end-to-end anastomosis was performed. The mare recovered completely, but 4 years later had colic caused by incarceration and volvulus of the distal portion of the jejunum, involving fibrous abdominal adhesions. The cause of hematoma was not identified; however, rupture of an intramural vessel after migration of Strongylus vulgaris larvae was considered a possibility because of the histologic observation of an...
Plenderleith RW.In large animal practice, clinical cases involving deep-seated infections affecting bones, joints, meninges and the larynx are particularly difficult to treat. The antibiotic lincomycin has the ability to penetrate tissue of poor vascularity and is also effective in the presence of pus. Eleven cattle, six sheep and three horses were treated with the drug at various doses and in 75 per cent of the cases there was a positive response.
Harrison IW, Raker CW.Bilateral arytenoidectomy had been performed as treatment for bilateral arytenoid chondritis in 2 horses. After surgery, dorsal mucosal defects were associated with subsequent development of dorsal glottic stenosis in the 2 horses. When performing bilateral arytenoidectomy in the horse, care must be taken to eliminate dorsal mucosal defects that cross the midline. Failure to close these defects may result in glottic stenosis.
Boyd EH, Allen WE.Plasma concentrations of neomycin were measured after intrauterine infusion of 3.3 mg/kg neomycin sulphate. Mares infected two hours previously with an intra-uterine infusion of beta-haemolytic streptococci absorbed approximately 12 per cent of the neomycin in both the oestrous and the luteal phases of the cycle. Normal mares in oestrus absorbed 6 per cent of the neomycin infused and luteal mares absorbed 56 per cent. In infected mares the peak plasma concentrations occurred two hours after neomycin infusion, earlier than in healthy mares. Cervical flushings after neomycin infusion in infected...
Young JD, Mason DK, Fincham DA.Na+-dependent system ASC and Na+-independent system asc are characterized by a common selectivity for neutral amino acids of intermediate size such as L-alanine and by their interactions with dibasic amino acids. For system ASC, the positive charge on the dibasic amino acid side chain is considered to occupy the Na+-binding site on the transporter. We report here the use of harmaline (a Na+-site inhibitor in some systems) as a probe of possible structural homology between these two classes of amino acid transporter. Harmaline was found to inhibit human erythrocyte system ASC noncompetitively w...
Bowling AT, Ewalt-Evans R.Family data are presented for a new allele (Aabdg) in the A system of horse erythrocyte alloantigens which includes factors Aa and Ab traditionally thought to be products of allelic genes. Evidence for incorrect assignment of the codominant factor Ae in the presence of Ab and Ac and the absence of Aa is discussed.
Delbeke FT, Teale P, Debackere M, Houghton E.A commercially available generic promazine ELISA kit is available which shows cross-reactivity for the tranquilizer chlorprothixene (CPT). The ELISA test readily detects the presence of CPT or its metabolites in equine urine for up to 24 h after the i.v. and i.m. administration of sub-therapeutic doses (4.5 mg) to three horses. Maximum concentrations (CPT equivalents) are obtained 2 h after i.v. dosing. No distinct concentration peak values are observed after i.m. administration. Following solid-phase extraction, confirmation of CPT and its metabolites by electron impact mass spectrometry afte...
Hassanain MM, al-Afaleq AI, Soliman IM, Abdullah SK.Two 7-year old Arabian racing horses were reported to show typical AHS symptoms in Qatar and died shortly after. The horses had been vaccinated with formol inactivated vaccine approximately 10 days before the onset of the disease. Blood samples from these horses were collected and AHS virus isolated from one sample after intracerebral (i.c.) inoculation into suckling mice. The virus identity was confirmed by complement fixation test (CFT) using the virus antigen and reference type 9 of AHS virus hyperimmune serum. The serotype of the isolated virus was identified by serum neutralization test (...
Tappenbeck K, Schmidt S, Feige K, Naim HY, Huber K.Lidocaine is the most commonly chosen prokinetic for treating postoperative ileus in horses, a motility disorder associated with ischaemia-reperfusion injury of intestinal tissues. Despite the frequent use of lidocaine, the mechanism underlying its prokinetic effects is still unclear. Previous studies suggested that lidocaine altered cell membrane characteristics of smooth muscle cells. Therefore, the present study aimed to elucidate effects of lidocaine administration on characteristics of detergent-resistant membranes in equine jejunal smooth muscle. Lidocaine administration caused significa...
Black B, Cribb NC, Nykamp SG, Thomason JJ, Trout DR.Artefacts caused by regional anaesthesia can influence image interpretation of ultrasonography and nuclear scintigraphy. Perineural and intrasynovial anaesthesia are commonly performed prior to magnetic resonance imaging (MRI); and the effects on MR images, if any, are unknown. Objective: To determine if perineural and intrasynovial anaesthesia of structures in the equine foot cause iatrogenic changes detectable with MRI. Methods: A baseline MRI examination of both front feet was performed on 15 horses, 2-6 days prior to mepivacaine injection adjacent to the lateral and medial palmar digital n...
Bonfig H.The purpose of this detailed description of the clinical examination of the colic patient is to arrive at a specific diagnosis. However, this is hardly ever possible, but the practitioner should be in the position to establish the suspicion of an intestinal obstruction or to rule out its presence during the course of the development. Single clinical findings should not be interpreted in isolation but in relation to one another, so that a false diagnosis is not made. All clinical findings should be documented, so that when repeated examinations are carried out, findings can be compared with one...
Story MR.Equine cervical pain and dysfunction may be difficult to diagnose and effectively manage. Understanding techniques in integrative medicine often allows the practitioner to observe and palpate areas of pain and dysfunction in the horse being evaluated in ways often not taught or used in conventional medicine. There are many integrative therapies that also may be utilized to more effectively manage these horses, resulting in a more comfortable and functional horse.
Schenk I, Machnik M, Broussou D, Meuly A, Roques BB, Lallemand E, Düe M, Röttgen H, Lagershausen H, Toutain PL, Thevis M.In horses, the benzodiazepine diazepam (DIA) is used as sedative for pre-medication or as an anxiolytic to facilitate horse examinations. As the sedative effects can also be abused for doping purposes, DIA is prohibited in equine sports. DIA is extensively metabolized to several active metabolites such as nordazepam, temazepam and oxazepam (OXA). For veterinarians, taking into account the detection times of DIA and its active metabolites is needed for minimizing the risk of an anti-doping rule violation. Therefore, a pharmacokinetic study on 6 horses was conducted using a single intravenous (...
Knych HK, Arthur RM, Stanley SD, McKemie DS.In order to ensure the welfare of performance horses and riders as well as the integrity of the sport, the use of both therapeutic and illegal agents in horse racing is tightly regulated. While Dehydroepiandrosterone (DHEA) is not specifically banned from administration to racehorses in the United States and no screening limit or threshold concentration exists, the metabolic conversion of DHEA to testosterone make its presence in nutritional supplements a regulatory concern. The recommended regulatory threshold for total testosterone in urine is 55 and 20 ng/mL for mares and geldings, respec...
Witte ST, Will LA, Olsen CR, Kinker JA, Miller-Graber P.Chronic selenosis (alkali disease) was diagnosed in horses of western Iowa, a region associated with marginal to adequate soil selenium. Two locally produced alfalfa hays (Medicago sativa L) were identified as the primary source. Difficulty in selecting diagnostic specimens to evaluate potential chronic selenosis cases is complicated by the wide range of tissue concentrations reported in previous cases, conflicting correlation of sample selenium concentrations in the literature, and different recommendations on specimen selection and diagnostic value. These problems arise form the similarity i...
Kolm G, Knapp E, Wagner R, Klein D.Interleukin-1beta (IL-1beta) is a primary cytokine of the skin that has a pivotal role in keratinocyte differentiation, epidermal wound healing and host defense. Pathological increase of cutaneous IL-1beta is associated with edema formation, epidermal hyperproliferation and atopic dermatitis in humans. However, in horses the role of cutaneous IL-1beta in edema formation and allergic skin disease has not been characterised so far. Particularly in Culicoides hypersensitivity (CHS), intradermal injection of Culicoides extract may be associated with enhanced transcription of local IL-1beta. To exa...
Alonso Jde M, Rodrigues KA, Yamada AL, Watanabe MJ, Alves AL, Rodrigues CA, Hussni CA.Heparin is routinely administered in postoperative abdominal surgery aiming to prevent adhesions formation; however, there is no consensus indicating its effectiveness. This study evaluated the effect of heparin on peritoneal reactivity after abdominal surgery, through the association between peritoneal fluid features and ultrasonographic and laparoscopic examination. Ten adult horses were used: control group (CG) and treated group (TG). Both groups underwent laparotomy and small colon enterotomy. TG received subcutaneous heparin at 150 IU/kg every 12 hours for 5 days. The animals underwent ...
Vreman S, Wiemer P, Keesler RI.A 10-year-old KWPN (Royal Warmblood Studbook of the Netherlands) gelding was euthanized after developing severe neurological symptoms preceded by severe epistaxis during laser treatment for progressive ethmoid haematoma (PEH) in the right nasal cavity. Postmortem examination of the head revealed a large amount of clotted blood between the right ventral and dorsal conchae in the nasal cavity and acute haemorrhage in the right subarachnoid space. Histologically, there was moderate, acute polioencephalomalacia in the neuropil adjacent to the haemorrhage. The haemorrhages were most likely caused b...
Denoix JM.Equine diagnostic sonography was initially used for the diagnosis and documentation of tendon injuries. Since 1990, this technique, along with radiography, has become an indispensable imaging procedure for the diagnosis of equine joint injuries. Sonography provides precise diagnostic information on the synovial membrane and fluid, the articular cartilage, subchondral bone and joint margins, the ligaments and menisci, and the anatomical structures involved in periarticular swelling or enlargement. Improvements in ultrasound machines and better superficial and deep image resolution allow us to e...
Brama PA, Rijkenhuizen AB, van Swieten HA, Warmerdam EP.The prognosis of aortic-iliac thrombosis (TAI) is usually considered to be poor, although affected horses are reported to have recovered following treatment with sodium gluconate. This paper presents some diagnostic techniques to monitor the development of hypoxemia in the diseased limb and to visualise the extension of the thrombosis into the femoral artery. Also, a surgical technique using a Fogarty thrombectomy catheter for partial or total removal of thrombi to restore blood flow, is described. One horse recovered completely, allowing it to resume its former career, the other horse improve...
Gruys E, Kok HA, Van Der Werff YD.Post-morten examination of a fourteen-year-old mare of the Gelderland breed, which had been treated for severe dyspnoea and had subsequenlty died, revealed the presence of haemothorax, atelectasis of the lung and a metastasized haemangiosarcoma of the left ovary. The haemothorax could have resulted from rupture of one of the metastases.
Dubuc J, Da Silveira EA.A 3-week old Hanoverian foal was presented with bilateral moderate to severe carpal valgus. The deviations were 10 and 14 degrees, respectively for the left and right carpi and orthogonal radiographs of both front limbs highlighted bilateral persistent ulnar remnants. A partial resection of the ulnar remnants and periosteal transection on the disto-lateral aspect of the radius were performed bilaterally under general anesthesia. The valgus deviations began to improve within the first month and the limbs were almost straight (2 degrees for the left and right carpi) 5 1/2 months after surgery. T...