Veterinary medicine for horses encompasses the study and application of medical practices to diagnose, treat, and prevent diseases in equine species. This field involves a comprehensive understanding of equine anatomy, physiology, pathology, and pharmacology. Veterinary practitioners employ a range of diagnostic tools and therapeutic interventions to address health issues in horses, including lameness, gastrointestinal disorders, respiratory conditions, and infectious diseases. Preventative care, such as vaccination and deworming programs, is also a significant aspect of equine veterinary medicine. This page gathers peer-reviewed research studies and scholarly articles that explore various aspects of veterinary medicine as it pertains to horses, including advancements in diagnostic techniques, treatment protocols, and preventive health strategies.
Sirois J, Betteridge KJ, Goff AK.The outcome of 23 collections and reinsertions of conceptuses on Days 10.5-13.5, 4 transfers of Day-10.5, and 13 transfers of Day-6.5 embryos (ovulation = Day 0) was monitored in 30 mares. Blood samples were taken before and after each procedure to measure plasma 15-keto-13,14-dihydroprostaglandin F-2 alpha (PGFM), and then daily for progesterone determinations. Mares were also subjected to daily teasing for detection of oestrus, and to uterine ultrasonography for tracing the development of the conceptus. After the reinsertions, 12/23 conceptuses were detectable immediately after the procedure...
Ricketts SW, Mackintosh ME.This study, performed over 3 breeding seasons, surveyed anaerobic and aerobic bacterial isolates from 362 clitoral and endometrial swabs and uterine washes from 263 Thoroughbred maiden, foaling, foal heat and barren mares, and from 113 urethral, urethral fossa, preputial and pre-ejaculatory fluid swabs from 29 Thoroughbred stallions. The significance of isolates was determined by their association with acute endometritis, as determined by concurrent endometrial smear results and by consideration of age and reproductive status before and after the survey. The results suggest that the horse uter...
Jöchle W, Irvine CH, Alexander SL, Newby TJ.Nine mares received cannulae to collect blood from the pituitary venous outflow in the intercavernous sinus (ICS) and the jugular vein; in 4 mares, only jugular cannulae were used. Those 4 mares and 3 of the mares with cannulae in both positions received 7.5 mg luprostiol i.m. and 1 mare with both cannulae was treated with 3.75 mg uprostiol i.v. Blood samples were kept before and after treatment at 2-, 5- or 10-min intervals and concentrations of LH, FSH and GnRH were determined by RIA. Treatments resulted in an immediate sharp rise of LH and FSH in ICS and jugular blood samples within 2-10 mi...
Hines KK, Fitzgerald BP, Loy RG.Changes in the pattern of LH and FSH in serum were studied in 6 mares foaling during the summer. Samples were collected frequently (every 15 min) for 24 h twice before foaling, -33 +/- 2 and -12 +/- 2 days, and for 12 h after foaling, on Day 0 and Day 4. Simultaneous pulses of FSH and LH were observed before foaling (r2 = 0.99). Before foaling, gonadotrophin pulses were infrequent (6 in 264 h of observation). On the day of foaling, LH and FSH pulse frequency increased (P less than 0.005) with 2-4 pulses per mare. The amplitudes of pulses of LH and FSH were higher before parturition than for th...
Bouchey D, Evermann J, Jacob RJ.Examination of six field isolates of equine herpesvirus 3, the causative agent of equine coital exanthema, indicates that all were temperature sensitive (ts) at the body temperature, 39 degrees C, of their host (Equine asinus and callabus) when grown in cell culture. The isolates were characterized by fingerprint analysis with the restriction endonucleases XbaI, EcoRI, BamHI and Hind III to establish possible epidemiologic relatedness. Three of the six isolates may be considered related. Variation in the mobility of the BamHI-A and Hind III-K fragments indicates that a small plaque isolate may...
McDonnell SM, Garcia MC, Kenney RM.Series of experiments and clinical trials were conducted to evaluate the effects of psychoneurotropic agents on sexual behaviour of stallions. The benzodiazepine derivative, diazepam (Valium), effectively reversed experimentally suppressed precopulatory arousal and response. Diazepam treatment also blocked the negative effect of novel environment on sexual response. The dibenzazepines imipramine and clomipramine induced erection, masturbation, and ejaculation in the absence of a sexual stimulus.
Jeffcott LB, Hyland JH, MacLean AA, Dyke T, Robertson-Smith G.Pregnant Standardbred mares were allocated to 2 groups. On Day 45 of gestation, 20-45 ml saline (240 g NaCl/l) were injected into the fetal sacs of 10 mares, and the other 10 mares were given sham treatment. Post-operative plasma oestrone sulphate concentrations were lower (P less than 0.01) on Days 48-55 in saline-treated mares than in sham-treated mares. Mean plasma progesterone profiles were similar in the two groups of mares, although post-operative luteolysis occurred in 4 saline-treated mares. There was no difference in plasma CG profiles between the 2 groups, except that CG concentratio...
Kraft W.Clinical symptoms of hepatopathies are not specific and must be verified by further investigation. Laboratory diagnosis is a very useful method to decide if liver disease is present or not. In individual cases laboratory methods can give hints as to the aetiology of the illness. If necessary, biopsy, angiography or/and cholecystography can be carried out for further clarification of the diagnosis.
Stewart F, Leigh SE, Thomson JA.Complementary (c)DNA libraries have been made from horse pituitary gland and endometrial cup tissues with the aim of isolating the genes for the horse gonadotrophins (FSH, LH and CG) and growth hormone (GH). Southern (DNA) and Northern (RNA) blotting techniques were used to demonstrate that several heterologous (human and ovine) cDNA probes would be adequate for isolating the horse genes. A human cDNA probe was then used to isolate the horse gonadotrophin alpha-subunit cDNA from the pituitary and endometrial cup libraries. The nucleotide sequences from both tissue sources were identical, there...
Beech J, Haskins M.A naturally occurring disease condition, neuraxonal dystrophy, was identified in 27 male and 15 female Morgans, many of which were closely related. Five-generation pedigrees were constructed for 33 of these horses and were compared with those for 29 randomly selected age- and sex-matched Morgans. Their mean coefficient of inbreeding was not statistically different (P greater than 0.1, 1 tailed t test; P less than 0.001, median test). Breeding of 2 severely affected and 2 normal stallions to 2 severely affected, 3 mildly affected, and 6 normal mares produced 10 mildly affected, 8 suspect affect...
Sentsui H, Kono Y.Horse erythrocytes treated with equine infectious anemia virus hemagglutinin were found to be lysed after incubation with fresh horse serum at 37 degrees C. Fresh guinea pig serum induced more efficient hemolysis than horse serum. Direct immunofluorescence test revealed the adsorption of complement factors on the surface of the erythrocytes. Calcium and magnesium ions were necessary for the hemolysis to take place. Antibody against equine infectious anemia virus enhanced the virus-induced complement-mediated hemolysis. These observations indicated that the classical pathway of complement activ...
Powers SK, Beadle RE, Thompson D, Lawler J.The purpose of these experiments was to examine the temporal pattern of arterial carbon dioxide tension (PaCO2) to assess the relationship between alveolar ventilation (VA) and CO2 return to the lung at the onset and offset of submaximal treadmill exercise. Five healthy ponies exercised for 8 min at two work rates: 50 m/min 6% grade and 70 m/min 12% grade. PaCO2 decreased (P less than 0.05) below resting values within 1 min after commencement of exercise at both work rates and reached a nadir at 90 s. PaCO2 decreased maximally by 2.5 and 3.5 Torr at the low and moderate rate, respectively. Aft...
Loch WE, Swantner LD, Anderson RR.Mean weight of 20 Quarter Horse placentas on a wet basis was 3.27 +/- 0.17 kg. These placentas contained mean dry fat-free tissue, DNA, RNA and collagen weights of 411 +/- 24 g, 11.2 +/- 0.6 g, 12.4 +/- 0.7 g and 210 +/- 15 g, respectively. In Ponies and Quarter Horses, there was a trend towards a decrease in these 4 values as gestation length increased. Analysis of placentas of Ponies fed different amounts of endophyte fungus-infected fescue seed showed that weight of dry fat-free tissue increased with increasing percentages of fescue seed in the diet. Diets containing fescue seed resulted in...
Johnston AM.Respiratory disease is one of the commonest medical reasons for referring a horse to the Royal Veterinary College, with coughing the main presenting sign. Investigation requires the taking of a detailed history, clinical examination, the use of appropriate diagnostic aids and noting response to medication and management changes. On arrival the horse is stabled in a minimal dust environment, remaining there until discharge. The use of a dust-free box frequently produces a favourable response without the use of medication which in itself is diagnostic. The problem of a horse which is asymptomati...
König HE, Ries R.The ovary of the mare is vascularized by two branches of the A. ovarica, which differ in diameter. They take a characteristic course in this organ. Near the ovulation fossa several branches of 1st and 2nd class leave the A. ovarica to provide the functional structures. These vessels are formed like a corkscrew. At the veins and its ramifications there are sphincter-like structures which support the venous valves. They are of haemodynamic importance for the different phases of the functional structures.
Allen WR, Kydd JH, Boyle MS, Antczak DF.Transfer of donkey embryos to horse mares provides a useful model of early fetal death. Endometrial cups do not develop in this one type of extraspecific pregnancy and 80% of donkey fetuses are aborted between Days 80 and 100 of gestation in conjunction with abnormal implantation and an intense accumulation of leucocytes in the endometrium of the surrogate mare. Treatment of mares carrying donkey conceptuses with progestagen (allyl trenbolone) or purified horse chorionic gonadotrophin does not prevent abortion. However, passive immunization with serum from mares carrying intraspecific horse fe...
Cohen JJ.Sunrise over the Rincon Mountains revealed a procession of fifty horses groaning under their burden of psychologists and immunologists as a recent desert workshop got under way. The participants later sat, some rather gingerly, around a table to discuss methodological questions central to the new and sometimes embattled field variously called behavioural immunology, psychoneuroimmunology, and neuroimmunomodulation.
Schuh JC, Valentine BA.Basal cell tumors from 11 horses were examined histologically. Distinct patterns identified in the order of frequency are adenoid (six), solid (three), and medusoid (two). A minor component of most of these neoplasms was a ribbon pattern and cystic spaces. Hyalinized connective tissue and clear cells reminiscent of hair follicle glassy membranes and outer root sheath were present in a solid and the medusoid tumors. Heavy melanin pigmentation was present in one solid basal cell tumor. In eight cases for which information was available, the tumors had not recurred 3 to 8 years after excision.
Thompson DL, McNeill DR, Wiest JJ, St George RL, Jones LS, Garza F.Sequential samples of blood were drawn via jugular catheters every 15 min for 24 h from four mares in each of five reproductive states: intact anestrous mares in winter, intact diestrous mares in summer, intact estrous mares in summer, ovariectomized mares in winter and ovariectomized mares in summer. Estrous mares were sampled on d 4 or 5 of estrus and diestrous mares on d 10 or 11 of diestrus. Each sample of plasma was assessed for concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) in two independent radioimmunoassays. A computer program was developed that dete...
Grabner A.Mycosis of the guttural pouches is a sporadic disease characterized by diphtheroid-necrotizing inflammation, and is caused by different fungal species, mainly by Aspergillus spp., Penicillium spp. and Candida spp. Highest incidence is during summer in stable horses. Proper diagnosis often requires--besides detection by mycological techniques--histological examination of tissue obtained by bioptic endoscopy. Prognosis is hopeless in late stages of the infection because of the erosion of the carotid artery or accompanied by the fatal complications of a not reparable cranial nerve damage also in ...
Baxter GM, Moore JN.Different dosages of aspirin were administered (by nasogastric tube) to 3 groups of 5 healthy adult horses to determine the minimal effective dosage needed to decrease serum thromboxane B2 (TxB2) concentrations and to determine the duration of this decrease. When compared with their base-line serum TxB2 concentrations, horses in group 1 (given 5 mg/kg) had a 71% decrease in TxB2 concentrations at 24 hours after aspirin was given and a 86% decrease at 48 hours; serum TxB2 concentrations were back to base-line values by 120 hours. Horses in group 2 (given 10 mg/kg) had a 60% decrease in TxB2 con...
Markel MD, Wheat JD, Jang SS.Nine Thoroughbred racehorses were admitted with cellulitis (of one or more limbs) associated with coagulase-positive staphylococci. The right hindlimb was affected in 4 horses, the right forelimb in 2, the left hindlimb in 1, and both hindlimbs in 2. Typical abnormalities included high values for rectal temperature (9 horses) and heart rate (5 horses), hyperfibrinogenemia (7 horses), leukocytosis (7 horses), and neutrophilia (6 horses). The staphylococcal isolants were speciated in 3 horses and classified as Staphylococcus aureus. Complications included skin loss (5 horses), laminitis of the a...
Allen D, White NA, Foerner JF, Gordon BJ.Thirteen horses with chronic refractory laminitis were evaluated and treated. In each horse, deep digital flexor tenotomy was performed on all affected limbs at the level of the midpastern. Five horses returned to limited athletic endeavors, 6 horses improved and were comfortable on pasture, 1 horse improved clinically, but was euthanatized for economic reasons, and 1 horse improved, but deteriorated 9 months after surgery and was euthanatized. Results of this study indicated that deep digital flexor tenotomy at the level of the midpastern can be used effectively as a salvage procedure in hors...
Voorhout G, Klein WR, Meutstege FJ.An avulsion fracture of the tendon of origin of the extensor digitorum longus muscle is reported in a horse and a cat. This avulsion fracture was due to injury in both animals. There was a striking similarity of radiographic findings in these animals, with involvement of the lateral trochlear ridge and lateral condyle of the femur. The horse was slaughtered because of a poor prognosis as a riding-horse. Fixation of the avulsed fragment with two Kirschner wires resulted in complete recovery in the cat.
Lane JG, Lucke VM, Wright AI.Papillomatous lesions intruding into the laryngeal airway were identified in an imported polo pony during a routine neurological examination for partial quadriplegia. Histological examination established a diagnosis of laryngeal besnoitiosis but it is unlikely that the laryngeal parasitism was associated with the cerebellar neuropathy which was also present.
Bidwell LA.Equine anesthesia is complicated regardless of the procedure being performed. Anesthesia for the mare experiencing dystocia is complicated by the size of the fetus, positioning of the mare for the procedure, and concern over drug effect on the fetus through the neonatal period. Anesthesia of the neonate is complicated by multiple factors, specifically, sensitivity to the drugs administered. Ventilatory support, minimizing drugs administered, and minimizing anesthesia time are essential for a positive outcome.
Palmisano M, Bender S, Johnson AL.We describe the unique clinical presentation of a central nervous system neoplasm in a 6-month-old draft horse cross gelding. Based on the neurologic examination at admission, neurolocalization was most consistent with a mildly asymmetric cervical, multifocal, or diffuse myelopathy. Mild vestibular involvement also was considered, but no cranial nerve deficits were observed. The gelding was negative for Sarcocystis neurona or Neospora hughesi based on paired serum and cerebrospinal fluid (CSF) samples analyzed, with no evidence of cervical compression based on contrast myelography. The horse w...
Charman RE, Vasey JR.Chronic facial defects extending into the sinuses of two mares were repaired using periosteal flaps. Partial osseous bridging was established over the defects following repair. Previous attempts to close the defects with skin alone had failed. A periosteal flap is a simple surgical technique that provides the foundations for successful repair, despite the chronicity of some fistulae.
Palmer JE, Benson CE.Sixteen healthy ponies were inoculated IV with Ehrlichia risticii-infected P388D1 mouse monocytes. Of the 16 ponies, 15 developed clinical signs of equine ehrlichial colitis. Twenty-four hours after onset of fever (rectal temperature > 38.8 C), 7 ponies were treated with 25 mg of erythromycin stearate/kg of body weight and 10 mg of rifampin/kg, given orally every 12 hours for 5 days. The remaining 8 ill ponies served as nontreated controls. All ponies were observed for progression of clinical signs typical of equine ehrlichial colitis. Within 12 hours of initiation of treatment, 4 of the 7 ...
Giordano A, Castagnetti C, Panzani S, Paltrinieri S, Freccero F, Veronesi MC.In newborn babies, endothelin 1 (ET-1), a potent vasoconstrictor, increases during septicemia and severe respiratory syndromes. Because equine neonatal sepsis (ENS) and perinatal asphyxia syndrome (PAS) are major causes of morbidity and mortality in newborn foals and because no information on the concentration of ET-1 in healthy and sick foals has been reported yet, the aims of this study were (1) to define the serum concentration of Big ET-1 in healthy neonatal foals during the first week of age; (2) to preliminarily explore the diagnostic and prognostic role of Big ET-1 during ENS and PAS. S...
Specht TE, Colahan PT.Eleven horses with acute or chronic incomplete cortical fractures of the left or right third metacarpal bone (McIII) were treated with surgical puncture (osteostixis). The fractures were diagnosed by physical examination and radiography. Four to eight holes, 2.7 or 3.5 mm in diameter, were drilled in the fractured bone. Radiographically, the fractures were healed by month 3, and the drill holes were inapparent by month 7. Nine horses (82%) returned to race competition, and two horses were retired, one the result of a surgical complication. The mean time between surgery and the first race was 9...
François L, Hoskens H, Velie BD, Stinckens A, Tinel S, Lamberigts C, Peeters L, Savelkoul HFJ, Tijhaar E, Lindgren G, Janssens S, Ducro BJ, Buys N....Insect bite hypersensitivity (IBH), which is a cutaneous allergic reaction to antigens from Culicoides spp., is the most prevalent skin disorder in horses. Misdiagnosis is possible, as IBH is usually diagnosed based on clinical signs. Our study is the first to employ IgE levels against several recombinant Culicoides spp. allergens as an objective, independent, and quantitative phenotype to improve the power to detect genetic variants that underlie IBH. Genotypes of 200 Shetland ponies, 127 Icelandic horses, and 223 Belgian Warmblood horses were analyzed while using a mixed model approach. No s...
Henderson WM.An attempt is made to review the validity of the claim that more equine research is required with the conclusion that the problems in the equine field that would respond to research must be listed and each assigned a degree of priority according to suggested criteria. Future action will then depend upon identifying or stimulating scientific initiative and seeking the required financial support noting that self help from the equine industry has not been adequately utilised.
Cavallero S, Pombi M, Perrone V, Milardi GL, D'Amelio S, Giuliani C, Gabrielli S.Larval forms of the bot-fly Gasterophilus are obligate parasites commonly found in the gastrointestinal tract of equids, causing intestinal myiasis. Five species are reported so far in Italy, mostly observed during necroscopy, located in different portion of gastrointestinal tract of equids: G. intestinalis, G. nasalis, G. inermis, G. pecorum and G. haemorrhoidalis. An unusual finding of larval Gasterophilus intestinalis deeply inserted into the diaphragmatic muscle is here reported. Due to the uncommon localization, to the absence of clinical signs related to myiasis and subsequent uncertaint...
Blue BJ, Pickett BW, Squires EL, McKinnon AO, Nett TM, Amann RP, Shiner KA.Gonadotrophin-releasing hormone (GnRH) was administered subcutaneously to reproductively normal stallions, either in a pulsatile manner (10 micrograms GnRH/2 h; n = 6) or as a continuous infusion (10 micrograms GnRH/2 h; n = 6), and in a pulsatile manner to 9 reproductively abnormal stallions, from February to July, 1988. Hormonal secretion patterns, testicular parameters and semen characteristics were monitored before and during treatment. In general, pulsatile GnRH caused a significant increase (P less than 0.05) in luteinizing hormone (LH) concentrations in the peripheral blood of normal st...
Peter AT, Colenbrander B, Gadella BM.The present study was designed to test the hypothesis that addition of anticaspase cocktails (inhibiting caspases and thus blocking apoptosis) to the extenders increases the post-thaw viability of equine spermatozoa. The addition of caspase inhibitors failed to improve the acrosome and plasma membrane integrity of spermatozoa, suggesting that in equine sperm cryopreservation protocols, the addition of these caspase inhibitors to cryopreservation medium may not be beneficial in protecting the sperm from the stress of cryopreservation.
Kraft W.Neurological examination in equine practice, physiological findings and pathological disturbances are described. Because of the sizes of the horse the neurological examination is more difficult than in small animals. The examination of cerebrospinal fluid is a worthful completion and is able to refer to the etiology of a certain disease. The technique of the puncture of cerebrospinal fluid is described.
Marquardt J, Heymer J, Heinz H, Deegen E, Adolf GR, Leibold W.Interferon is known to induce antiviral mechanisms and to exert immunoregulatory capacities on various cell types. The antiviral capacity of recombinant equine interferon-beta 1 (rEqIFN-beta 1) is most sensitively monitored by indirect quantitation of multiplication of vesicular stomatitis virus (VSV) in blood cells of horses. As few as 0.5 pg rEqIFN-beta 1/ml can be assessed by means of 90% reduction of VSV-replication in whole blood (w.b.) as well as in isolated mononuclear blood cells (MNC) in spite of individual variations. The immunoregulatory influence of 20-50 pg rEqIFN-beta 1/ml is suf...
Vivrette SL, Irvine CH.Acyclic mare given oestradiol for 3 days to simulate the preovulatory plasma oestradiol surge showed a non-significant 37% decrease in plasma LH during treatment. When GnRH analogue injections were given with oestradiol on Days 1--3, oestradiol had no effect on each GnRH-induced LH increase, but LH increases were more prolonged following subsequent GnRH injections on Days 4--7 when oestradiol was no longer being given. A much greater prolongation of LH release occurred when the course of GnRH injections was commenced after oestradiol treatment ceased; the LH response was almost identical to th...