Pedunculated lipomas as a cause of intestinal obstruction in horses: 17 cases (1983-1990).

The medical records of 17 horses that were evaluated and treated because of colic caused by pedunculated lipomas between 1983 and 1990 were reviewed. The mean age of the horses was 16.6 +/- 3.9 years (range, 10 to 26 years), which was significantly greater than that of the population of horses evaluated because of colic (control population) during the same period. There were significantly more geldings (76.5%), compared with the control population. Nasogastric reflux ranged from 1 to 16 L in 8 horses and was not obtained in 9 horses. Abdominal palpation per rectum revealed small intestinal distention in 13 horses, displaced large colon in 7 horses, and large colon impaction in 2 horses. Peritoneal fluid was abnormal in 11 of 12 horses from which it was obtained successfully. One horse was euthanatized after unsuccessful medical treatment. Surgery was performed in 16 horses. Lipomas were blindly resected in 5 horses or exteriorized and resected in 6 horses. The method used to resect the lipoma was not recorded in 5 horses. The ileum and/or jejunum was strangulated in 15 horses, the small colon was strangulated in 1 horse, and the jejunum was obstructed in 1 horse. The length of intestine resected ranged from 0.15 to 7.2 m. Fourteen horses survived surgery, of which 11 were discharged from the hospital (short-term survival rate of 78.6%). Excluding 2 horses lost to follow-up evaluation, 6 of 12 horses that survived surgery were alive 2 to 56 months following surgery (long-term survival rate of 50%), and 9 of 15 horses died or were euthanatized (fatality rate of 60%).     

Open drainage, intra-articular and systemic antibiotics in the treatment of septic arthritis/tenosynovitis in horses.

Open drainage was used to treat 26 horses with persistent or severe septic arthritis/tenosynovitis. Infected synovial structures were drained through a small (3 cm) arthrotomy incision that was left open and protected by a sterile bandage. Joint lavage was performed in all 26 horses. In addition to systemic antibiotics, 23 of these horses were also treated with intra-articular antibiotics; amikacin (17 horses), gentamycin (2 horses), cefazolin (2 horses), and 2 horses were injected at different times with gentamycin and amikacin. The infection was eliminated from the involved synovial structures in 25 of 26 horses; 24 survived and were released from the hospital. The arthrotomy incisions healed by granulation in 16 horses; in 9 horses the arthrotomy incision was sutured closed once the infection was eliminated. Seventeen horses returned to soundness and resumed athletic function. Open drainage was an effective method of achieving chronic drainage from a joint or tendon sheath. It is indicated in horses that have established intra-synovial infections or in horses that do not respond to joint lavage through needles.     

Arthrodesis of the proximal interphalangeal joint affected with septic arthritis in 8 horses

Arthrodesis was performed to treat septic arthritis of the proximal interphalangeal joint of 8 horses. Records of the horses were reviewed to determine outcome and possible factors that influenced success or failure. All horses were female. Seven horses had 1 joint treated and 1 horse was treated for bilateral pelvic limb involvement. The duration of sepsis before surgery ranged from 1 to 66 days. Bone lysis and production was radiographically apparent in 7 horses before surgery. Six horses had multiple bacterial organisms cultured from bone or synovial tissues; 2 horses had single isolates identified. After aggressive curettage, arthrodesis was accomplished with 3 parallel screws in 1 horse, 2 divergent narrow dynamic compression plates in 3 horses, and a single broad dynamic compression plate in 4 horses. Casts were applied to all horses for 1 to 6 weeks. Four horses survived to successful brood mare status. Four horses were euthanized during hospitalization because of continued discomfort or complications of sepsis. Arthrodesis of the proximal interphalangeal joint affected with septic arthritis appears to be an acceptable alternative to euthanasia for some horses.     

Severe carpometacarpal osteoarthritis in older Arabian horses

OBJECTIVE: To report a severe form of carpometacarpal osteoarthritis (CMC-OA) affecting primarily older Arabian horses. STUDY DESIGN: Retrospective study. ANIMALS: Thirty-one horses with CMC-OA. METHODS: Carpal radiographs (405 sets) from 3 hospitals were evaluated to identify horses with marked osteoproliferative reaction across the medial aspect of the CMC joint. Owners were contacted to obtain detailed histories and status updates. Necropsy specimens of the CMC joint were evaluated at 2 hospitals to determine the prevalence of 2 variations in the articulation between the proximal second and third metacarpal bones. RESULTS: Thirty-one horses were identified as having marked osteoproliferative reaction at the CMC joint. Twenty-three (74%) were Arabian horses. Of the Arabian horses, the average age at admission was 14.4 years. Eight (34.8%) Arabian horses had a known history of trauma. Most were no longer rideable at presentation. Ten of the horses were subsequently euthanatized because of lameness. The dorsal and palmar articulations between the second and third metacarpal bones were examined in 177 horses. The palmar articulation was absent in 48% of Arabian horses and 12.5% of non-Arabian horses at 1 center, including 4 horses with CMC-OA. At the second center, the palmar articulation was present in 8 of 8 Arabian horses but was absent in 22 of 92 (24%) non-Arabian horses. CONCLUSIONS: An increased frequency of this crippling form of OA was observed in Arabian horses. It may reflect an increased prevalence, in some geographical regions, of an absent palmar articulation between the second and third metacarpal bones. CLINICAL RELEVANCE: Carpal trauma in some Arabian horses may result in unexpectedly severe carpometacarpal osteoarthritis.     

Medical and surgical management of small-colon impaction in horses: 28 cases (1984-1989).

Medical records of 28 horses with impaction of the small colon were reviewed; 20 horses were admitted during the winter months. Diagnosis of small-colon impaction was made in 21 horses by rectal examination, and in 7 horses at exploratory celiotomy. Ten horses were treated medically, and 18 were treated surgically. Horses that were treated surgically were more likely to have abdominal distention than were those that responded to medical treatment (P less than 0.025). Signs of greater degree of abdominal pain and higher heart rate were seen in horses treated surgically, but these values were not significantly different from values in medically treated horses. Duration of hospitalization was less in horses treated medically (P less than 0.025). Long-term survival was higher for horses treated medically (P less than 0.025). All horses treated medically and 7 of the horses treated surgically were alive at follow-up evaluation, at least 1 year after discharge. Fever and diarrhea were common complications after surgery. Four horses were fecal culture-positive for Salmonella sp after surgery. Early and aggressive medical management of horses with impaction of the small colon is recommended.     

Complications of nasogastric intubation in horses: nine cases (1987-1989).

Pharyngeal or esophageal trauma was diagnosed in 9 horses after nasogastric intubation. Evidence of trauma (edema or ulceration) was detected in the pharynx of 3 horses and in the esophagus of 6 horses. Complications associated with nasogastric intubation were first observed in 5 horses while they were intubated and in 4 horses after extubation. Clinical signs of pharyngeal or esophageal trauma were similar, and included salivation, bruxism, coughing, and nasal discharge. Treatment, including extubation, enteral feeding through a small nasogastric tube, or esophagostomy distal to the affected site, was attempted in 6 horses. Three of 6 treated horses survived, but 4 of 5 horses with perforated esophagus were euthanatized.     

Cellulitis associated with coagulase-positive staphylococci in racehorses: nine cases (1975-1984)

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 affected limb (2 horses), laminitis of the contralateral limb (4 horses), osteomyelitis and sequestrum formation (2 horses), and bacteremia (1 horse). Five horses were euthanatized because of the severity of the complications, ie, laminitis in 4 horses and severe skin loss in 1 horse. The remaining 4 horses were discharged from the clinic. At follow-up evaluation (mean, 16.7 months), the swelling in 3 of the horses had completely resolved. One horse returned to racing; of 2 used for pleasure riding, one was mildly lame. The remaining horse was not lame, but was used for breeding because of persistent swelling of the affected limb.     

Circumferential Wiring of Mid-body and Large Basilar Fractures of the Proximal Sesamoid Bone in 15 Horses

Circumferential wiring was used to repair 12 mid-body fractures and four large basilar fractures of proximal sesamoid bones in 15 horses. Eighteen-gauge stainless steel wire was placed around both fragments in five horses, and through the proximal fragment and around the distal fragment in 10 horses. The horses were returned to work when they were clinically sound and fracture healing was evident radiographically. Eleven horses resumed athletic performance, three horses were used as breeding animals, and one horse was retired. Five horses performed at an athletic level equal to or better than their previous levels, and six horses performed at a lower level.     

Comparison of the diagnosis and management of unilaterally castrated and cryptorchid horses at a referral hospital: 60 cases (2002-2006)

OBJECTIVE: To determine the incidence of unilaterally castrated horses among horses admitted to the hospital for castration and to compare horses that underwent previous unilateral castration with horses that had cryptorchism. DESIGN: Retrospective case series. ANIMALS: 16 unilaterally castrated horses and 44 cryptorchid horses. PROCEDURES: Medical records of horses that were admitted to the veterinary medical teaching hospital for castration, including cryptorchid and unilaterally castrated horses, between January 2002 and December 2006 were reviewed. Medical records of unilaterally castrated horses and cryptorchid horses were examined for age, breed, history, diagnostic procedures, surgical technique of cryptorchidectomy, location of the retained testicle, and cost of surgery. RESULTS: Of 160 horses admitted for castration, 16 (10%) had undergone previous unilateral castration and 44 (27.5%) had cryptorchidism. Unilaterally castrated horses were significantly older than cryptorchid horses. No significant difference was found in left versus right distribution of testicles. No significant difference was found in abdominal versus inguinal distribution of left-sided testicles. Unilaterally castrated horses had a significantly lower proportion of right inguinal testicles, compared with cryptorchid horses. The cost of diagnosis and management of unilaterally castrated horses was significantly greater than in cryptorchid horses. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the distribution of retained testicles is significantly different in unilaterally castrated horses, compared with cryptorchid horses, which may affect the selection of diagnostic and surgical approaches to unilaterally castrated horses.     

Treatment of horses with chronic diarrhea: immunologic status.

All chronically diarrheal horses given (orally) 2 series of treatments with normal horse serum recovered in 2 to 4 weeks. However, mild diarrhea sometimes persisted several months in the group of horses with severe diarrhea. Weight gains were approximately 35% in horses with severe diarrhea and approximately 10% in horses with mild diarrhea. Serum specimens from 12 diarrheal and 20 normal horses were examined for immunoglobulins by single radial immunodiffusion technique. Concentration of immunoglobulin A in serum of diarrheal horses was approximately 50% lower than that in serum of normal horses. By contrast, there was more immunoglobulin G in serum of diarrheal horses than in serum of normal horses. Phytohemagglutinin (PHA-M) responsiveness of blood lymphocytes showed transient suppression during the stage of severe diarrhea. The regaining of PHA-M responsiveness of lymphocytes was observed simultaneously with the recovery process. However, the responsiveness of lymphocytes in recovered horses remained markedly lower than that in normal horses. Allergic reactions in diarrheal and normal horses were studied by observing dermal response to injections of saline extracts from some of the horse feeds. A delayed hypersensitivity reaction to streptokinase-streptodornase and PHA-M was also studied. Allergic reactions to these extracts were not induced in either diarrheal or normal horses; however, inflammatory response to the extracts was approximately 50% greater in normal than in diarrheal horses. Response to intradermal injection of either streptokinase-streptodornase or PHA-M was significantly greater in normal horses than in diarrheal horses.     

Evaluation of glucose tolerance and intestinal luminal membrane glucose transporter function in horses with equine motor neuron disease

OBJECTIVE: To confirm whether the plasma glucose concentration curve obtained during oral glucose tolerance tests (OGTTs) in horses with equine motor neuron disease (EMND) is decreased, compared with that obtained in clinically normal horses, and determine whether that decrease is a result of defective glucose metabolism or intestinal glucose transport dysfunction. ANIMALS: 8 horses with EMND and 44 matched control horses. PROCEDURE: Electromyography and OGTTs were performed in all 8 affected horses and 10 control horses. Intravenous GTTs (IVGTTs) were performed in 6 affected horses and another 11 control horses. The activity and levels of jejunal luminal membrane glucose transporter (Na+ / glucose cotransporter isoform 1 [SGLT1]) were measured in 2 affected horses and 23 control horses. RESULTS: In horses with EMND, generalized neuropathy was detected via quantitative electromyography; the mean increase in plasma glucose concentration during the OGTT was significantly decreased, compared with the value in control horses. During the IVGTT the mean increase in plasma glucose concentration was significantly lower than that of control horses. The activity and levels of SGLT1 in 2 affected horses were similar to those of control horses. Diagnosis of EMND was confirmed postmortem in all affected horses. CONCLUSIONS AND CLINICAL RELEVANCE: Data suggest that the decreased plasma glucose curve obtained in horses with EMND during OGTTs (compared with control horses) is a result of overall enhanced glucose metabolism or abnormalities in the facilitated glucose transporters; definitive identification of the underlying mechanisms could aid in the development of appropriate treatments of EMND in horses.     

Esophageal Disorders in 61 Horses: Results of Nonsurgical and Surgical Management

Obstructive esophageal disorders in 61 horses included feed or foreign body impaction (27 horses), strictures (18 horses), perforations (11 horses), and diverticula (5 horses). Horses with feed impaction were treated nonsurgically (25 horses) or by esophagotomy (2 horses). Survival to discharge was 78%, and 37% of these had persistent chronic obstruction at home. Long-term survival was 52%. Long-term survival of nine horses treated nonsurgically for esophageal strictures was 22%; for nine horses treated surgically it was 44%. Long-term survival of horses treated nonsurgically was significantly better in acute than chronic strictures. Surgical repair of esophageal mural strictures was more successful than repair of annular or mucosal strictures. One third of the horses with strictures were foals. Long-term survival for horses with strictures was 33%. Long-term survival was higher for the horses with perforations managed surgically (2 of 4) than nonsurgically (0 of 7). Long-term survival for this group was 18%. One esophageal diverticulum was managed nonsurgically, and four were treated surgically; all horses survived long term. Complications of obstructive esophageal disorders included aspiration pneumonia, chronic obstruction, esophageal mucosal ulceration, postoperative infection, pleuritis, laminitis, laryngeal paralysis, and Horner's syndrome.     

Influence of age of horse on results of quantitative electromyographic needle examination of skeletal muscles in Dutch Warmblood horses

OBJECTIVE: To determine the influence of age on results of quantitative analysis of electromyographic (EMG) needle examination in the subclavian, triceps, and lateral vastus muscles of Dutch Warmblood horses. ANIMALS: 7 healthy young Dutch Warmblood horses (range, 13 to 18 months old), 7 healthy adult Dutch Warmblood horses (range, 4 to 10 years old), and 7 healthy elderly Dutch Warmblood horses (range, 18 to 21 years old). PROCEDURE: An EMG needle examination was performed to evaluate insertional activity, spontaneous activity, and motor unit action potential (MUAP) variables. Although all horses were conscious, young horses were sedated prior to examination. RESULTS: Mean insertional activity in young horses was significantly lower than in elderly horses. Pathologic spontaneous activity was rarely found in young and adult horses but was frequently evident in all muscles in all elderly horses. The MUAP duration and amplitude were significantly lower in all muscles of young horses, compared with values for adult and elderly horses. The MUAP duration and number of phases and turns were significantly lower in adult horses than in elderly horses. Group differences for percentages of polyphasic and complex MUAPs were also found. The 95% confidence intervals for MUAP duration, MUAP amplitude, and number of phases and turns for the subclavian, triceps, and lateral vastus muscles were significantly lower in young horses than in adult or elderly horses. CONCLUSIONS AND CLINICAL RELEVANCE: Age of the horse being examined should be considered when EMG examination is performed.     

Esophageal disorders in 61 horses. Results of nonsurgical and surgical management

Obstructive esophageal disorders in 61 horses included feed or foreign body impaction (27 horses), strictures (18 horses), perforations (11 horses), and diverticula (5 horses). Horses with feed impaction were treated nonsurgically (25 horses) or by esophagotomy (2 horses). Survival to discharge was 78%, and 37% of these had persistent chronic obstruction at home. Long-term survival was 52%. Long-term survival of nine horses treated nonsurgically for esophageal strictures was 22%; for nine horses treated surgically it was 44%. Long-term survival of horses treated nonsurgically was significantly better in acute than chronic strictures. Surgical repair of esophageal mural strictures was more successful than repair of annular or mucosal strictures. One third of the horses with strictures were foals. Long-term survival for horses with strictures was 33%. Long-term survival was higher for the horses with perforations managed surgically (2 of 4) than nonsurgically (0 of 7). Long-term survival for this group was 18%. One esophageal diverticulum was managed nonsurgically, and four were treated surgically; all horses survived long term. Complications of obstructive esophageal disorders included aspiration pneumonia, chronic obstruction, esophageal mucosal ulceration, postoperative infection, pleuritis, laminitis, laryngeal paralysis, and Horner's syndrome.     

Rupture of collateral ligaments in metacarpophalangeal and metatarsophalangeal joints in horses: 17 cases (1999--2005)

OBJECTIVE: To characterize ruptures of collateral ligaments (CLs) in metacarpophalangeal and metatarsophalangeal joints in horses. DESIGN: Retrospective case series. ANIMALS: 17 horses with ruptured CLs. PROCEDURES: Data were obtained from medical records, including signalment, history, clinical signs, ultrasonographic and radiographic findings, treatment, and outcome. Additional follow-up information was obtained from owners or referring veterinarians. RESULTS: The lateral CL was ruptured in 11 horses; the medial CL was ruptured in 6 horses. Ultrasonography revealed ipsilateral rupture of the short and long components of the CL in 11 horses and rupture of only 1 component in 6 horses. No biaxial ruptures were detected, but 9 horses had desmitis of the CL on the nonruptured side of the affected joint. All horses were lame (lameness score range, 2/5 to 4/5). Joint instability was palpable in 9 horses; only 4 horses had episodes of joint luxation. Avulsion fractures were identified radiographically in 6 horses and ultrasonographically in another 2 horses. Stress radiography revealed joint instability in 10 horses. Horses were managed by stall confinement, limb immobilization, and gradual return to exercise. Eight horses returned to riding, 2 resumed breeding, 2 were retired, 2 were euthanized, and 3 were doing well 86 to 139 days after injury. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonographic examination is indicated in horses with acute lameness and swelling at the metacarpophalangeal or metatarsophalangeal joint, particularly when stress radiography cannot be performed or findings are equivocal. Affected horses can be conservatively managed. Prognosis for athletic use may be better than originally believed.     

Outcome of medical and surgical treatment of cecal impaction in horses: 114 cases (1994-2004)

OBJECTIVE: To determine short- and long-term outcomes, including recurrence rates, for horses with cecal impaction treated medically or surgically. DESIGN: Retrospective case series. ANIMALS: 114 horses. PROCEDURES: Medical records were reviewed for information on signalment, history, clinical findings, treatment (medical vs surgical), and short-term outcome. Information on longterm outcome was obtained through a mail survey and telephone interview with owners. RESULTS: 54 horses were treated medically, 49 horses were treated surgically, and 11 horses were euthanized after initial examination without further treatment. Horses treated surgically were significantly more likely to have signs of moderate or severe pain than were horses treated medically. Forty-four of the 54 (81%) horses treated medically were discharged from the hospital. Twelve of the 49 horses treated surgically were euthanized at surgery because of cecal rupture. Thirty-five of the 37 (95%) horses that were allowed to recover from surgery were discharged from the hospital. In 34 horses treated surgically, typhlotomy without a bypass procedure was performed. Long-term (>or= 1 year) follow-up information was available for 19 horses treated medically and 28 horses treated surgically. Eighteen (95%) and 25 (89%) of the horses, respectively, were alive at least 1 year after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that medical and surgical treatment were both associated with favorable outcomes in horses with cecal impactions. In this population, typhlotomy alone without cecal bypass was associated with a low recurrence rate. The long-term prognosis for horses that were discharged from the hospital was good.     

Equine Melanocytic Tumors: A Retrospective Study of 53 Horses (1988 to 1991)

A study of 57 cutaneous melanocytic tumors from 53 horses revealed 4 distinct clinical syndromes: melanocytic nevus, dermal melanoma, dermal melanomatosis, and anaplastic malignant melanoma. Melanocytic nevus and anaplastic melanoma each had histopathologic features that distinguished them from dermal melanoma and dermal melanomatosis. Dermal melanoma and dermal melanomatosis were histologically similar but could be differentiated by their clinical features. Melanocytic nevi were diagnosed in 29 horses with an average age of 5 years; they were solitary, superficial masses that occurred in both grey and nongrey horses, and in which surgical excision was generally curative. Dermal melanomas were diagnosed in 20 horses with an average age of 13 years; all horses of known coat color were grey. Eight horses with an average age of 7 years had 1 or 2 discrete dermal melanomas. Follow-up information was available for 6 horses; metastases occurred in 2 horses, and surgical excision was apparently curative in 4 horses. Dermal melanomatosis was diagnosed in 12 grey horses with an average age of 17 years; all 6 of these horses evaluated had internal metastases. In 2 aged nongrey horses with anaplastic malignant melanoma, the tumors metastasized within 1 year of diagnosis. Two tumors with features of both melanocytic nevus and dermal melanoma remained unclassified.     

Evaluation of a cranial arthroscopic approach to the stifle joint for the treatment of femorotibial joint disease in horses: 23 cases (1998-1999)

OBJECTIVE: To describe a single-portal cranial arthroscopic approach to the stifle joint in horses and to determine the clinical outcome in horses with femorotibial joint disease in which this approach was used. DESIGN: Retrospective study. ANIMALS: 23 adult horses. PROCEDURE: Medical records were reviewed to obtain information on clinical outcome in horses in which the single-portal cranial arthroscopic approach was used. RESULTS: Twenty-nine stifle joints of 23 horses were examined arthroscopically, using the described approach. Subchondral bone cysts were treated in 19 medial femoral condyles of 12 horses. Unilateral cruciate ligament desmitis (4 horses), meniscal tearing (3), or both (2) were identified in 9 horses. Evidence of degenerative joint disease without cystic lesions or soft tissue trauma was found in 2 horses. Information on clinical outcome was obtained for 21 of 23 horses. A successful outcome was obtained in 15 of 21 horses and was defined as return to sound performance at a degree equal to or better than that prior to injury and lameness. Eight of 12 horses treated for medial femoral condylar cysts had a successful outcome. Four show horses treated for cruciate ligament lesions alone successfully returned to showing activity. None of the 3 horses with meniscal tearing were able to perform successfully. CONCLUSIONS AND CLINICAL RELEVANCE: The femorotibial joint was evaluated through a single-portal cranial arthroscopic approach, using the femoropatellar joint as the point of access. This approach was easy to perform, allowed controlled access to the femorotibial joint, avoided accidental damage to articular structures, and required fewer access portals.     

Necrosis of the nasal conchae in 12 horses

Twelve horses with a history of a unilateral malodorous nasal discharge were examined clinically, endoscopically and radiographically. The head of one of the horses was examined by computed tomography. Tissue samples were taken for microbiology from four of the horses and for histology from three. The conchal necrosis was unilateral in 11 of the horses and bilateral in the other, and no particular concha was affected more than the others. The affected tissue was removed transendoscopically with a polypectomy snare while the horses were sedated and standing. Mild disinfectants were used locally in six of the horses. After the removal of all the necrotic tissue, the affected concha healed without any complications in all 12 horses.     

Abdominal Auscultation in the Detection of Experimentally Induced Gastrointestinal Sand Accumulation

A blind study was designed to determine if abdominal auscultation is an effective method for detecting the presence of intestinal sand. Fifteen horses divided into two groups were used in the study. There were seven horses in Group 1 and eight horses in Group 2. All horses were auscultated and determined to be free of sand sounds before initiation of Trial 1. Group 1 horses were given 4.2 g/kg body weight of sand via nasogastric tube using carboxymethylcellulose (CMC) as a suspending agent at 9.0 ml/kg body weight. Group 2 horses were given CMC only. Horses remained in the same group through all trials. A total of five trails, each lasting 24 hours, was performed. Dosing with sand and CMC or CMC alone was repeated at the beginning of each trial. Abdominal auscultation was performed on each of the 15 horses beginning on Trial 2 by an investigator with no knowledge of the grouping of the horses. The ventral abdomen was auscultated for 5 minutes at 7 hours and 17 hours after trial initiation. When a horse was considered positive for intestinal sand by auscultation, the horse was eliminated from future trials. On Trial 2, no horses were positive; on Trial 3, one horse; on Trial 4, two horses, and on Trial 5, four horses. Sounds considered characteristic for sand in the intestinal tract were eventually identified in all Group 1 horses. No horses in Group 2 were ever identified as having sounds characteristic for intestinal sand at any point during this investigation.