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.
Huntington PJ, Forman AJ, Ellis PM.This paper reports the first isolation of equine arteritis virus (EAV) in Australia and serological evidence of exposure to EAV in Australian horses. Twelve Standardbred stallions imported from North America were found to shed EAV in semen. One hundred and seven stallions were tested for serum antibodies to EAV and 73% of Standardbred stallions tested were seropositive as compared to 8% of Thoroughbred stallions. Serum antibody was detected in 71% of Standardbred mares, 6% of Standardbred racehorses and 1% of Thoroughbred mares and racehorses. Examination of stored serums demonstrated that EAV...
McCarthy PH.A detailed description is given of the structures forming the borders of Viborg's triangle and those structures contained within and adjacent to the triangle. Changes in the size, shape and prominence of these structures with changes of head and neck posture of the horse are also described.
Eicker SW, Cuvelliez S.Inhalation anesthesia has three requirements: delivery of oxygen, delivery of an appropriate concentration of a volatile anesthetic agent, and removal of carbon dioxide. Halothane and isoflurane are the most commonly used anesthetic agents. They are usually delivered with a semiclosed circle system using an out-of-the-circuit vaporizer. Carbon dioxide is eliminated by chemical absorption and by flow of excess oxygen and waste anesthetic agent through the pop-off valve. These gases should be scavenged to prevent room contamination. A variety of ancillary equipment is available to assist the ane...
Piquette GN, Kenney RM, Sertich PL, Yamoto M, Hsueh AJ.The association of equine granulosa-theca cell tumors with atrophied contralateral ovaries and abnormal estrous cycles suggests that these tumors produce hormones that affect pituitary gonadotropin production. Because inhibin, a heterodimer protein secreted by granulosa cells, decreases FSH production, we examined the presence of inhibin alpha- and beta A-subunits and their mRNAs in ovarian tumors obtained from three mares. These tumors contained neoplastic cords and nodules, multiple fluid-filled cysts, and a predominance of neoplastic granulosa cells. Reduced proteins from tumor-conditioned ...
Krause HD, Sieme H, Merkt H, Bader H, Wöckener A.A reduction in the motility of the spermatozoa in stallion semen stored in pellet form for 23 years in liquid nitrogen at -196 degrees C could not be seen after thawing. The insemination of a mare with this semen resulted in a normal pregnancy. A normally developed, healthy male foal was born after a gestational period of 321 days.
Cummings LE, Guthrie AJ, Harkins JD, Short CR.Gentamicin sulfate, equivalent to 4 mg of gentamicin base/kg of body weight, was administered IV to 6 Thoroughbred foals on day 1 (12 to 24 hours of age) and at 5, 10, 15, and 30 days after birth. On day 40 after parturition, gentamicin was given to the mares at a dosage similar to that used in foals. Decay of serum gentamicin concentrations was best described by a 2-compartment model. Among foals, the overall elimination rate constant at 30 days of age was significantly (P less than 0.05) greater than at days 1, 10, and 15. There was, however, no difference in the overall elimination rate con...
Seahorn TL, Carter GK, Martens JG, Crandell RA, Martin MT, Scrutchfield WL, Cummins JM, Martens RJ.The immunotherapeutic effect of low-dose human alpha interferon on viral shedding and clinical disease was evaluated in horses inoculated with equine herpesvirus-1 (EHV-1). Eighteen clinically healthy weanling horses, 5 to 7 months old, were allotted to 3 equal groups. Two groups were treated orally with human alpha-2a interferon (0.22 or 2.2 U/kg of body weight), on days 2 and 1 before inoculation with EHV-1, the day of inoculation, and again on postinoculation day 1. The horses of the remaining group were given a placebo orally on the same days. The horses were monitored daily for changes in...
Forster HV, Pan LG, Flynn C, Bisgard GE.The purpose of this study was to determine whether there was any recovery of the Hering-Breuer inflation reflex in ponies between 2-4 wk and 3-4 yr after hilar nerve denervation (HND). Under anesthesia and before HND, airway occlusion after a 3-liter lung inflation lengthened the subsequent occluded breath by nearly 10 times the control breath duration. Between 2 wk and 3-4 yr after HND, this maneuver increased the duration of the occluded breath by only 2.5 times the control breath duration. Also under anesthesia, the airway was occluded at end expiration. This maneuver increased the duration...
Tranquilli WJ, Thurmon JC.Several unique pharmacologic and physiologic factors must be considered when attempting to anesthetize premature or neonatal foals. Juvenile foals are similar to adults in their physiology and metabolism. Anesthetic drug and protocol selection should reflect the differences between these two age groups. Neonates are best anesthetized using an inhalation technique, whereas older foals can be safely anesthetized with either parenteral or inhalation anesthetic agents. Careful monitoring is absolutely essential when anesthetizing foals. The clinician should plan to routinely administer fluids and ...
Schmotzer WB, Timm KI.Successful diagnostic local anesthesia is dependent upon a thorough knowledge of appendicular anatomy, application of correct technique, and accurate interpretation. Use of cadaver specimens to review anatomy and practice needle placement is strongly recommended. A marker solution, such as new methylene blue, can be injected into cadaver limbs, which can be subsequently dissected to verify accuracy. Detailed interpretation of local anesthetic blocks in the lame horse reaches beyond the scope of this article. Interpretive difficulties, however, can be responsible for the failure of a block to p...
Geor RJ, Clark EG, Haines DM, Napier PG.Systemic lupus erythematosus (SLE) was diagnosed in a 2-year-old Standardbred filly. Clinical signs of SLE included weight loss, bilateral symmetric alopecia, seborrhea, oral ulceration, and lymphadenopathy. Abnormal laboratory findings included a Coombs test-positive hemolytic anemia and positive antinuclear antibody test result. Histologic evaluation of multiple skin biopsy specimens revealed interface dermatitis with linear deposition of IgG at the basement membrane zones of the epidermis and hair follicles. The filly did not respond to glucocorticoid treatment and was euthanatized. Necrops...
Sironi G, Caniatti M, Scanziani E.One hundred and seventy-two hyperplastic and neoplastic epithelial lesions from 8 different mammalian and 1 avian species have been tested with an immunohistochemical technique to detect papillomavirus structural antigens. Selected lesions were diagnosed histologically as papilloma, fibropapilloma, equine sarcoid, squamous cell carcinoma, basalioma, epulis, keratoacanthoma, trichoepithelioma, pilomatrixoma, epidermal inclusion cyst, and hyperkeratotic or acanthotic epidermal lesions. Positive nuclear staining was detected in 14 out of 23 papillomas, 8 out of 32 fibropapillomas and in 1 out of ...
Whetter L, Archambault D, Perry S, Gazit A, Coggins L, Yaniv A, Clabough D, Dahlberg J, Fuller F, Tronick S.A full-length molecular clone of equine infectious anemia virus (EIAV) was isolated from a persistently infected canine fetal thymus cell line (Cf2Th). Upon transfection of equine dermis cells, the clone, designated CL22, yielded infectious EIAV particles (CL22-V) that replicated in vitro in both Cf2Th cells and an equine dermis cell strain. Horses infected with CL22-V developed an antibody response to viral proteins and possessed viral DNA in peripheral blood mononuclear cells, as determined by polymerase chain reaction assays. In addition, horses infected with CL22-V became persistently infe...
Art T, Anderson L, Woakes AJ, Roberts C, Butler PJ, Snow DH, Lekeux P.The changes induced by exercise on the mechanics of breathing, as well as the simultaneous changes occurring in arterial blood gas tensions and in respiratory gas exchange were investigated in 6 healthy thoroughbred horses, performing a treadmill exercise of increasing intensity. Respiratory airflow and tidal volume (VT) were measured with ultrasonic flowmeters. Pleural pressure changes were measured by an oesophageal balloon catheter. Gas concentration of the expired air was analysed with a mass spectrometer; the oxygen consumption (VO2) and the carbon dioxide output (VCO2) were computed brea...
Prasse KW, Allen D, Moore JN, Duncan A.The balance of coagulation and fibrinolysis was studied in 15 horses during the prodromal stages of acute laminitis induced by carbohydrate overload. Progression of the disease was stopped 12 to 24 hours before the expected onset of lameness in trial 1 (8 horses) and at the onset of lameness in trial 2 (7 horses). The end points in each trial were identified by specific changes in blood pressures (trial 1) and by changes in pulse, rectal temperature, and arterial pressure (trial 2) that were anticipated on the basis of original description of the experimental model. Blood samples for hemostasi...
King JN, Gerring EL.The effect of pre-treatment with a selective platelet-activating factor (PAF) antagonist, WEB 2086, on the actions of low-dose endotoxin was evaluated in ponies prepared with gastrointestinal strain gauges. Endotoxin (0.1 microgram/kg i.v.) produced a marked reduction in gastric contraction amplitude and rate, and an increased frequency and reduced duration of jejunal phase III activity fronts (AFs). WEB 2086 (6.6 mg/kg) administered i.v. 10 min before the endotoxin, produced significant antagonism (P less than 0.001) of the effect of endotoxin on gastric contraction amplitude and rate. The co...
Wakuri H, Sakuma Y, Mutoh K, Watanabe S.In 6 equine specimens of both sexes, the morphological features of the cleavage lines of the skin over the entire body were examined using a metal probe with a sharp conical point. Wounds were produced on the skin with the probe and painted with Chinese white or Indian ink. The direction of running of the cleavage lines was determined from their relationship to the long axis of each region or area of the physical structure. The cleavage lines of the head and face revealed a fixed pattern in all specimens. They were similar to those of equine fetuses of 6 to 7 months of age. A transverse patter...
Shawley RV, Mandsager RE.Positive-pressure ventilation is used to provide improved ventilatory support during anesthesia in the horse. Because of the horse's size and the physiologic changes it undergoes during anesthesia, however, the use of positive-pressure ventilation does not always provide the improvement seen in smaller species. Careful attention to respiratory rate, inspiratory pressure, and I:E ratio minimizes the negative aspect of IPPV on the cardiovascular system. The goal of future ventilatory techniques will be to improve oxygenation without cardiovascular compromise and to do so at a reasonable cost to ...
Kellerman TS, Marasas WF, Thiel PG, Gelderblom WC, Cawood M, Coetzer JA.Leukoencephalomalacia (LEM) was induced by the oral administration of fumonisin B1 (FB1) to 2 horses: a filly received 59.5 mg/kg of a 50% preparation of FB1, administered in 21 doses of 1.25-4 mg/kg over 33 days; a colt, 44.3 mg/kg of 95% pure FB1 in 20 doses of 1-4 mg/kg in 29 days. Both animals developed nervous signs such as apathy, changes in temperament, inco-ordination, walking into objects, and one showed paralysis of the lips and tongue. Characteristic lesions of LEM were present in the brains. These trials proved conclusively that FB1 can induce LEM in horses.
Coyne CP, Carlson GP, Spensley MS, Smith J.In this preliminary investigation, various hematologic variables potentially influential in determining the degree of blood viscosity were evaluated in 10 Thoroughbred horses subjected to competitive acute running exercise. Following completion of sprints over a distance of 1.25 miles, mean percent (+/- SD) increases in PCV (38.3 +/- 12.9%), RBC (47.8 +/- 15.3%), and rouleaux index (232.7 +/- 176.8%) were recognized. Simultaneous increases in total plasma protein (28.3 +/- 5.31%), serum albumin (26.7 +/- 6.80%), alpha 1-globulin (60.0 +/- 49.0%), alpha 2-globulin (25.5 +/- 27.9%), beta 1-globu...
Geiser DR.Chemical restraint in the standing horse is used for a variety of procedures in veterinary medicine. The choice of agent depends on the physical status, temperament, and size of the patient; the procedure to be performed; and safety for the patient, veterinarian, and owner. The combination of certain agents may provide more desirable restraint and analgesia than does the use of individual agents. The use of analgesics in the horse is not without side effects, some of which may be detrimental to the patient's condition. Analgesics should be chosen with these untoward effects in mind. Draft bree...
LeBlanc PH.Organ toxicity from local anesthetic agents is rare. This makes these agents an attractive option in the high-risk patient. Complications associated with local anesthetics are related to overdosage. Overdosage with local anesthetic agents administered epidurally may cause motor paralysis and hind-limb weakness. Systemic signs of local anesthetic overdosage include changes in central nervous system activity (excitement or depression), muscle tremors, and hypotension. Because the dose required to produce these effects in the horse is high (12 mg/kg), this complication is uncommon. Few side effec...
Kamphues J, Meyer H, Liebler EM, Johannsen A.Anamnesis and clinical signs of horses form five different stables after ingestion of ionophores are reported and techniques of feed examination are described. Within a few hours or days after feeding of new types or batches of concentrates horses fell ill. They showed colic-like symptoms with intense sweating and ataxia. Most of the sick animals died within a short time span. Samples of the concentrates were analysed and different types and amounts of ionophores were detected. In four cases contamination by monensin in concentrations of less than 5 mg to 679 mg/kg feed were found. One feed sa...
Allen D, Clark ES, Moore JN, Prasse KW.A carbohydrate overload model was used in 8 horses to evaluate Starling forces and hemodynamics of the digit during the prodromal stage of acute laminitis. A pump-perfused extracorporeal digital preparation was used to evaluate blood flow, arterial pressure, venous pressure, capillary pressure, isogravimetric capillary filtration coefficient, osmotic reflection coefficient, and vascular compliance. From these data, pre- and postcapillary resistances and pre- to postcapillary resistance ratios were determined. Vascular and tissue oncotic pressures were estimated from plasma and lymph protein co...
Georgiev P, Petkov PI, Georgiev Kh, Bŭrzev G.Parallel physiologic, biochemical, and hormonal investigations of racehorses were carried out within the time period of a training cycle. The changes found in the physiologic and biochemical indices were said to be in a general relationship with the amount of physical training of the animals, at the same time reflecting some seasonal variations. The changes in the level of T-4 and cortisol were found to be in direct relationship with the continuation of training.
Claessen C, De Lange V, Huang T, Ma G, Osterrieder N, Favoreel H, Van de Walle GR.Equine herpesvirus 1 (EHV1) is an α-herpesvirus that can infect a variety of different cells in vitro and in vivo, including dendritic cells (DC) which are essential in the immune response against EHV1. Infection of equine monocyte-derived DC (MDDC) with EHV1 induced down-regulation of major histocompatibility complex I (MHCI), CD83, CD86, CD206, CD29 and CD172a, but not of CD11a/CD18 and MHCII. This down-regulation was not mediated by the virion host-shutoff (VHS) protein or pUL49.5. Interestingly, down-regulation of CD83 and CD86 was in part mediated by pUL56. Taken together, these data ind...
Ginther OJ, Bergfelt DR.Incidence of embryo reduction (natural elimination of one member of a twin set) before d 11 was studied by comparing the number of ultrasonically detected conceptuses per ovulation between single and double ovulators. Effect of unilateral (n = 24) vs bilateral (n = 26) double ovulations on the incidence of embryo reduction also was considered. Each of 50 double-ovulating mares was matched with two single ovulators yielding 100 ovulations, or potential embryos, per group. Frequency with which an ovulation resulted in a conceptus was greater for single ovulators (85%, P less than .01) and for bi...
Moorman VJ, Jann HW.A 2-day-old Thoroughbred intact female was presented for a large subcutaneous swelling in the right inguinal region. Surgical repair was performed using a double layer polypropylene mesh. To the authors' knowledge, there have been no previous reports of surgical repair of congenital body wall hernias with polypropylene mesh in foals. Une femelle pur sang intacte âgée de deux jours est présentée pour de l’enflure sous-cutanée importante dans la région inguinale droite. Une réparation chirurgicale est réalisée en utilisant une double couche de maille de polypropylène. À la connaiss...
Bernard W, Reef VB, Clark ES, Vaala W, Ehnen SJ.Records of 6 horses with pericarditis were reviewed. Septic pericarditis was suspected in all horses, based on historic and clinical findings. In horses 1, 2, and 4, cytologic examination of the pericardial effusion revealed acute inflammation with severe neutrophil degeneration. In horses 3 and 5, cytologic examination of pericardial fluid revealed subacute inflammation with degenerated neutrophils, and in horse 6, chronic active inflammation, with well preserved neutrophils. In horses 1 and 3, bacteria were identified on cytologic examination of pericardial fluid. Results of microbiologic cu...
Oishi S.The author has already reported on the time course of blood level of sulfonamides in horses at various dose schedules3). The present paper is concerned with the tissue distri-bution of sulfadimethoxine and sulfamonomethoxine in horses. The distribution of sulfonamides has been reported by KoNDol) in experimental animals, in which the concentrations of these drugs in the kidney, liver, lung and spleen were found to be close to the blood level. Many investigators ascribed the low concen-tration of sulfonamides in the spinal fluid to the existence of a blood-brain barrier, and also observed that ...
Perryman LE, Mason PH.Monoclonal antibodies (MAbs) have been successfully used to evaluate immune responses in horses, and to target important antigens of equine infectious agents to which protective immune responses may be directed (1–5). Most of these studies are performed with murine MAb produced by fusing spleen cells from immunized mice with an appropriate myeloma cell line, as described in Chapter 3. However, there are experimental questions for which murine MAb are not adequate. These include:
1.Definition of microbial epitopes recognized by the infected host;
2.Identification of immunodominant epito...
Dyke TM, Hinchcliff KW.Ceftiohr sodium was evaluated as a therapy for respiratory
infections in horses. This cephalosporin antimicrobial was
administered intramuscularly every 24 h and at a dose of 2.2
mglkg (1.0 mgllb) of body weight. The efficacy of ceftiofur
sodium was compared with that of a positive control drug,
ampicillin sodium (recommended dose of 6.6 mg/kg [3 mg/lb],
given every 12 h). Both treatments were continued for 48 h
after clinical symptoms were no longer evident (maximum of
10 days). Fifty-five (55) horses with naturally acquired
respiratory infections were included in the study; 28 were
...
Birks EK, Hultgren BD.A primary pericardial haemangiosarcoma with metastasis to the parietal pleura and left adrenal gland is described in a 22-year-old Clydesdale x Percheron gelding. Although haemangiosarcomas have been reported in horses, the pericardium has not hitherto been described as the primary site of origin.
Eberly VE, Tyler WS, Gillespie JR.EBERLY, V. E., W. S. TYLER, AND J. R. GILLESPIE. Cardio-vascular parameters in emphysematous and control horses. J. Appl. Physiol. 2 1 (3) : 883-889. I 966.—Horses with clinical signs of chronic pulmonary emphysema were demonstrated to have heart rates, total peripheral vascular resistance, pulmonary vascular resistance, and mean pulmonary artery blood pres-sure highly significantly greater than normal. They also had a highly significant decrease in central blood volume, stroke volume, stroke index, and left ventricular work. Cardiac out-put was significantly lower than in control (normal) h...
Hu J, Brooks M, Fuller AL, Armstrong P, McDougald LR.Cultured Histomonas meleagridis cells were readily agglutinated in vitro by horse serum at concentrations as low as 5%, although clumping was more rapid and prominent at 15% or higher. For observation of clumping, the cultured organisms were washed twice in Hanks balanced solution (HBSS) by centrifugation (1,000 x g for 15 min) and filtered through glass wool. The test sera were added and the mixture incubated in a Petri plate or 24-well culture plates at r.t. for 15-30 min. Formation of clumps was time- and concentration-dependent. Gentle agitation hindered agglutination at low serum concentr...
Labonville M, Higgins R, Lavoie JP.The aim of the study was to assess the relation between the direct smear observations and bacteriological results carried out on equine tracheal secretions. A total of 304 cases comprising both the direct smear (Gram stain) and the bacteriological culture, over a period of 8 years, were submitted to this retrospective study. Most of the specimens (78%) were obtained using tracheal washings while the rest (22%) originated from tracheal brushings. A total of 96 specimens (32%) were negative for both direct smear and culture. The positive predictive value of direct smears appeared high (81-96%) w...
Tallmadge RL, Antczak DF, Felippe MJB.Host defenses against infection by viruses, bacteria, fungi, and parasites are critical to survival. It has been estimated that upwards of 7% of the coding genes of mammals function in immunity and inflammation. This high level of genomic investment in defense has resulted in an immune system characterized by extraordinary complexity and many levels of redundancy. Because so many genes are involved with immunity, there are many opportunities for mutations to arise that have negative effects. However, redundancy in the mammalian defense system and the adaptive nature of key immune mechanisms bu...
Carter SD, Osborne AC, May SA, Bennett D.To consider the hypothesis that autoimmune mechanisms may contribute to the pathology of equine joint diseases, 3 autoimmune responses were assayed in sera and synovial fluids. IgM-rheumatoid factor and antibodies to heat shock protein 65 kDa were determined by ELISA; anti-nuclear antibodies were assayed by indirect immunofluorescence to whole cell nuclear components. All parameters showed only modest increases, if any and not in a pattern related to disease, although some statistically significant increases were detected. Group analysis showed significantly elevated synovial fluid IgM-rheumat...
Dabernat HJ, Tainturier D, Delmas C, Ferney J, Lareng MB.The cultural, biochemical, antigenic and antibiotic susceptibility characteristics of 17 strains of Haemophilus equigenitalis, the causative organism of contagious equine metritis (CEM), were studied. Biochemical characteristics were investigated using both conventional method and the API ZYM system of enzyme detection. The biochemical profile of the H. equigenitalis strains was unique and differed from the other bacterial species studied under the same experimental conditions (H. influenzae and H. parainfluenzae, B. abortus and B. melitensis, P. multocida, A. calcoaceticus). The required X an...
Acland HM, Mann PC, Robertson JL, Divers TJ, Lichtensteiger CA, Whitlock RH.Six foals of three different breeds, born to healthy mares, appeared normal at birth, and died at two to five days of age with icterus, ataxia, head pressing, and terminal hepatic coma. Their livers were less than one-half normal weight. Most of the liver was dark red-brown and slightly rubbery. Histologically, these areas were characterized by severe bile ductule proliferation, mild portal tract fibrosis, and massive hepatocellular necrosis and lobular collapse. A small proportion of the liver, usually on the peripheral part of the lobes, was grossly light brown and slightly raised. Histologi...
Colbern GT, Moore JN.A patellar fracture was identified radiographically in the right stifle of a mature Tennessee Walking Horse stallion. The horse was markedly lame (grade IV/V) on the right hindlimb. Due to the articular nature and small size of the fragment, surgical removal via arthrotomy was selected. A dorsomedial approach to the femoropatellar joint was used. The horse recovered well and has returned to training as a show horse by 8 months following surgery.
Marlow CH.Horse breeding in South Africa started in 1652, shortly after the 1st European settlement in the Cape. African horsesickness posed a serious problem and after a devastating outbreak of the disease in 1719, horses were largely replaced by oxen for agricultural and transport purposes but remained important from a sporting and military point of view. Examples of the latter are the export of horses for military use to India in the mid-19th century and for use in the Crimean War in 1854, reaching a zenith in the Anglo-Boer war in which an estimated 450 000 horses succumbed. Research and disease con...
Frost GE, du Preez HR.A 3 year old thoroughbred colt in full training pulled up
acutely lame during a training gallop on a dirt track.
According to the trainer no reason for the injury was
evident. The horse refused to bear weight on the leg
and when forced to walk back to the stables it would
only touch the affected toe to the ground. The fetlock
soon became swollen and was very painful. The trainer
treated the animal for a sprain with ice packs and
bandages. No improvement occurred in 72 hours and
veterinary advice was sought.
Examination revealed the horse to be in obvious
pain. He was unable to bear ...
Jongbloets AM, Sloet van Oldruitenborgh-Oosterbaan MM, Meeus PJ, Back W.Equine canker is a chronic, hyperplastic, exudative pododermatitis affecting one or more feet. Although many causes and treatments have been suggested, the cause of the disease is still unknown and most probably multifactorial. Local treatments include radical surgical debridement of the diseased hoof tissue and application of caustic substances, antibiotics, and pressure bandaging. Nevertheless, the number of recurrences is high (45%). This article presents a 3-year-old New Forest pony-cross mare in which all horny structures (frogs, coronets, spurs, chestnuts) of all feet were affected. Bact...
Glover ID, Henry GM, Townsend NB, Coles GC.The Stomacher is very widely used in food and medical research for extracting tissues. To determine whether nematode larvae were disrupted by the Stomacher, L3 larvae of Haemonchus contortus were homogenised for up to 40 min at full power but no larval disruption occurred. Therefore, tissue from the mucosa and submucosa of the caecum of horses collected from a licenced abattoir was treated to determine whether inhibited cyathostomin larvae could be extracted. The optimum time on full power for a 10-g sample was 20 min, and in three out of five caecal samples from different horses, significantl...