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Objective: To evaluate equids with enostosis-like lesions (ELLs) and document the clinical and epidemiological features of this disease., Design: Retrospective case series., Animals: 79 equids with a scintigraphic diagnosis of at least 1 ELL on ≥ 1 occasion., Procedures: Medical records of 4,992 equids that underwent bone scintigraphy between March 1997 and March 2009 were reviewed; 78 horses and 1 pony had a scintigraphic diagnosis of an ELL. For those equids, signalment; physical, scintigraphic, radiographic, and lameness examination results; and outcome were reviewed., Results: Of the 79 equids, 4 (5.1%) had anatomically distinct ELLs on 2 (n = 3) or 4 (1) separate occasions that caused lameness in different limbs. Thus, there were 85 ELL-related admissions to the hospital. Overall, 157 ELLs were detected. Among all equids undergoing scintigraphic examination, Thoroughbreds were more commonly and Standardbreds were less commonly affected. Older animals were more likely to have ELLs. Lameness was directly attributed to scintigraphically evident ELLs in 42 of the 85 (49.4%) admissions. The tibia (62/157 [39.5%]) and the radius (46/157 [29.3%]) were most commonly affected. The ELLs located in the humerus caused more severe lameness than did ELLs in other anatomic locations. Lameness severity was associated with radiopharmaceutical uptake intensity. Among racehorses, those with 1 ELL were more likely to return to racing than were those with multiple ELLs detected in 1 scintigraphic examination; mean interval from diagnosis to first start was 184 days., Conclusions and Clinical Relevance: Results of this retrospective evaluation of a large group of equids with ELLs have provided a better understanding of this disease process.

Objective: To determine whether topical application of 1% diclofenac sodium cream would decrease inflammation at sites of IV regional limb perfusion (IVRLP) in healthy horses., Animals: 6 healthy adult horses (12 forelimbs)., Procedures: Bilateral IVRLP with 2.5 g of amikacin sulfate was performed twice in each horse, with 24 hours between each session. Horses were treated with topical 1% diclofenac liposomal cream (treated limbs) or a placebo cream (control limbs). All injection sites were evaluated before the first IVRLP session and 24 hours after the second session by means of ultrasonographic examination by a trained ultrasonographer who was unaware of the treatment received. Circumferential measurements and subjective visible inflammation scores were recorded by a veterinarian who was also unaware of treatment received., Results: After IVRLP, control limbs had a significantly greater increase in subcutaneous thickness, compared with treated limbs. Ultrasonographic and visual assessment scores were significantly higher in control versus treated limbs. The mean change in limb circumference was greater, but not significantly so, in control limbs, compared with treated limbs., Conclusions and Clinical Relevance: Topical application of 1% diclofenac sodium liposomal cream to sites of IVRLP in healthy horses decreased inflammation as judged by visual assessment and ultrasonography. Decreased inflammation may allow extended use of IVRLP and may result in a reduction in pain in treated horses.

Objective: To compare results (ie, return to racing and earnings per race start) of surgical versus nonsurgical management of sagittal slab fractures of the third carpal bone in racehorses., Design: Retrospective study., Animals: 32 racehorses (19 Thoroughbreds, 11 Standardbreds, and 2 Arabians)., Procedure: Medical records and radiographs were reviewed to obtain information regarding signalment and treatment. Follow-up information was obtained from race records. Robust regression analysis was performed to evaluate earnings per start in horses that raced at least once before and after injury., Results: 22 (69%) horses raced at least once after treatment of the fracture. All 7 horses treated by means of interfragmentary compression raced after treatment, and horses that underwent interfragmentary compression had significantly higher earnings per start after the injury than did horses treated without surgery. Eight of 9 horses treated by means of arthroscopic debridement of the damaged cartilage and bone raced after treatment, but only 7 of 16 horses treated without surgery (ie, stall rest) were able to return to racing after treatment., Conclusions and Clinical Relevance: Results suggest that racehorses with sagittal slab fractures of the third carpal bone have a favorable prognosis for return to racing after treatment. Horses treated surgically were more likely to race after treatment than were horses treated without surgery.

Objective: To report the outcome of surgical treatment of comminuted fractures of the proximal phalanx in horses., Design: Retrospective study., Animals: 64 horses., Procedure: Medical records and radiographs were reviewed to obtain information regarding signalment, fracture classification, and treatment. Follow-up information was obtained by telephone conversation or evaluation of production records., Results: Thirty-eight horses had moderately comminuted fractures of the proximal phalanx. Two horses were euthanatized immediately. Fractures of the proximal phalanx in 36 horses were repaired with open reduction and internal fixation with a successful outcome in 33 (92%) horses. Reconstruction of the fracture was performed in most horses by use of a long curved incision, transection of the collateral ligament of the metacarpophalangeal or metatarsophalangeal joint, and open exposure of the proximal articular surface of the proximal phalanx. Twenty-six horses had severely comminuted fractures of the proximal phalanx. Six horses were euthanatized immediately. One horse was euthanatized after 9 days of treatment with a cast alone. Severely comminuted fractures of the proximal phalanx in 13 horses were treated with an external skeletal fixation device, and fractures healed in 8 of those horses. Six horses with severely comminuted fractures of the proximal phalanx were treated with transfixation pins incorporated into a fiberglass cast, and fractures healed in 4 horses., Conclusions and Clinical Relevance: Moderately comminuted fractures of the proximal phalanx can be successfully repaired; however, fractures that are too severe to permit accurate reconstruction of the fragments remain difficult to treat and horses have only a fair prognosis for survival.

Objective: To identify scintigraphic abnormalities in the pelvic region of horses examined because of hind limb lameness or poor performance and determine the clinical relevance of areas of abnormal radiopharmaceutical uptake (ARU) in these horses., Design: Retrospective study., Animals: 128 horses., Procedure: Medical records were reviewed, and information on signalment, history, admitting complaints, physical examination findings, and results of lameness examinations was recorded. Clinical relevance of areas of ARU was determined by comparison with results of other diagnostic tests. For horses with clinically relevant areas of ARU, follow-up information was obtained through telephone interviews with owners and trainers and analysis of race records., Results: Areas of ARU were identified in the tuber coxae (25 horses), ischiatic tuber (9), hip joint (10), third trochanter (10), ilium (5), sacral tuber region (22), greater trochanter (1), cranial femoral cortex (1), skeletal muscle surrounding the pelvis (34), or multiple areas (11). In 44 horses, areas of ARU were associated with the primary cause of lameness; in 51, areas of ARU were not associated with the primary cause of lameness; and in 33, the primary cause of lameness was not determined. Thirty-six of the 44 horses with clinically relevant areas of ARU were available for follow-up; 15 (42%) had a good outcome., Conclusions and Clinical Relevance: Results suggest that pelvic scintigraphy may be useful in identifying abnormalities in horses with hind limb lameness or poor performance.

Objective: To determine features of postoperative wound infection caused by Actinobacillus spp in horses undergoing clean, elective surgery and to evaluate bacterial susceptibility profiles of bacteria isolated., Design: Retrospective study., Animals: 10 horses., Procedure: Data were retrieved from medical records and the microbiology laboratory database., Results: 1,604 horses underwent clean, elective surgical procedures during the study period. Of these, 23 (1.43%) had postoperative wound infections, and Actinobacillus spp was isolated from 10 of these 23 (43%). Surgical procedures in these 10 horses included laryngoplasty with ventriculocordectomy (n = 3), arthroscopy (3), desmotomy of the accessory ligament of the superficial digital flexor tendon (2), removal of laryngoplasty prostheses (1), and hygroma resection (1). Seven horses survived, and 3 were euthanatized. All 10 Actinobacillus isolates were resistant to penicillin, and 6 were resistant to trimethoprim-sulfamethoxazole. All isolates were susceptible to ceftiofur and gentamicin. During the 5-year period of the study, Actinobacillus organisms were isolated from 35 of 513 (6.8%) samples from the general hospital population submitted for bacterial culture and antimicrobial susceptibility testing., Conclusions and Clinical Relevance: During the study period, Actinobacillus spp was isolated from a higher than expected percentage of horses that developed postoperative wound infections after clean, elective surgery. Susceptibility profiles for these isolates were different from typical susceptibility profiles for Actinobacillus isolates, suggesting that a pattern of resistance may be emerging.

Objective: To describe the pool-raft recovery system protocol and to evaluate the clinical outcome in horses that underwent recovery from general anesthesia using this system., Design: Retrospective study., Animals: 393 horses that underwent recovery from general anesthesia in the pool-raft system., Procedure: Anesthetic records were examined from horses recovered from anesthesia in the pool-raft system between January 1984 and December 2000. Complete medical records of horses were examined when available. Information regarding the anesthetic and recovery period was recorded. Horses first recovered from general anesthesia in the pool-raft and, once awake, were transported to a recovery stall and lowered to the floor in a standing position., Results: 351 horses underwent 1 pool-raft recovery, and 42 horses underwent multiple pool-raft recoveries. Most horses were recovered from general anesthesia within the pool-raft system to safeguard repair of a major orthopedic injury. During 471 pool-raft recoveries, 34 (7%) horses had complications within the recovery pool and 62 (13%) had complications within the recovery stall. Deaths resulted from complete failure of internal fixation, pulmonary dysfunction, or a combination of pulmonary dysfunction and fixation failure in 2% (10/471) of horses that underwent pool-raft recoveries., Conclusions and Clinical Relevance: The pool-raft system is a good option for recovery from general anesthesia. Although not a fail-safe system, it appears to decrease the complications of recovering horses in a high-risk category. Potential disadvantages of this system are added expense and manpower necessary in building, maintenance, and usage, as well as size limitations of the raft itself.

Four horses were evaluated because of hind limb lameness. Two had a distinct gait abnormality at the walk characterized by lateral rotation of the point of the calcaneus and medial rotation of the toe during the stance phase. Nuclear scintigraphy revealed a focal area of intense radioisotope uptake in the caudodistal aspect of the femur in all 4 horses, and 3 of the horses had a corresponding proliferative reaction on the caudodistal cortex of the femur on radiographs. In all 4 horses, a diagnosis of injury to the origin of the gastrocnemius muscle was made. Three of the horses returned to athletic endeavors after an extended period of rest and a gradual return to exercise. The fourth improved after 5 months of rest but became lame again when returned to exercise and was euthanatized.

Objective: To determine the prognosis in horses with cecocolic or cecocecal intussusception., Design: Retrospective study., Animals: 30 horses with cecocolic intussusception or cecocecal intussusception., Procedure: Information on history, physical examination findings, and laboratory values was summarized from the medical records. Laboratory data included results of hematologic examination, serum biochemical analysis, and peritoneal fluid color, total nucleated cell count, and total protein concentration. A one-year follow-up via the telephone was used to determine long-term survival., Results: Horses ranged from 7 months to 30 years old, but 63% were < or = 3 years. Standardbred horses were significantly overrepresented. Twenty-six horses had acute-to-subacute disease, and 4 had a chronic wasting disease. Cecal intussusceptions were suspected on the basis of finding a mass on abdominal palpation per rectum (14 of 24 horses) and positive ultrasonographic findings (2 of 3 horses). Thirteen horses with colic for > 1 day had scant, soft feces. Six horses died or were euthanatized without undergoing surgery, and 24 were treated surgically. Six of the latter horses were euthanatized during surgery because of peritonitis, rupture of the cecum, and irreducible intussusception. All 4 horses with a chronic disease were euthanatized because of irreversible changes in the cecum. Of the 18 horses allowed to recover from surgery, 15 survived long-term. Surgical treatments were reduction, with or without partial typhlectomy (6 horses), partial typhlectomy through a colotomy and reduction (6), reduction through a colotomy and partial typhlectomy (3), partial typhlectomy for a cecocecal intussusception (1) and an ileocolostomy (2)., Clinical Implications: Cecal intussusception has a good prognosis with surgical correction without delay. Reduction through colotomy has a high success rate. Bypass by ileocolostomy should be used as a last resort.

Objective: To assess the effect of incomplete, midsagittal fractures of the proximal phalanx (P1) on racing performance in Standardbreds., Design: Retrospective cohort study., Animals: 49 Standardbred horses admitted to the George D. Widener Hospital for Large Animals between July 1986 and December 1992 with a definitive radiographic diagnosis of an incomplete, midsagittal fracture of P1 and a known method of treatment., Procedure: Performance index and racing time were compared before and after diagnosis and treatment of fracture, using ANOVA that controlled for the effects of horse, gender, age, track length, and track condition., Results: Expected racing time increased by 0.7 seconds and performance index decreased by 0.7 points, although controlling for factors known to affect racing performance had a substantial impact on these results., Clinical Implications: Standardbreds with incomplete, midsagittal fractures of P1 have a favorable prognosis for return to racing; recovered horses will likely have slower racing times and decreased performance indices.

A 4-year-old sexually intact male Standardbred trotter was evaluated for left forelimb lameness. A presumptive diagnosis of severe cartilage damage was made because the horse had a history of infectious arthritis involving the left metacarpophalangeal joint. Arthroscopic evaluation revealed what was presumed to be a large villonodular lesion. The mass was surgically removed, and the horse was treated with procaine penicillin G, trimethoprim-sulfamethoxazole, phenylbutazone, and polysulfated glycosaminoglycans and eventually returned to racing. Histologic examination of the mass revealed a bed of granulation tissue covered with keratinized epithelium. We hypothesize that the lesion developed secondarily to implantation of epithelial cells into a reactive villonodular lesion.

A 1-year-old polled Hereford heifer was admitted with a mass of the rostral mandibular area that had been observed 17 days earlier. Cytologic examination of fluid aspirated from the mass revealed normal blood. Radiography revealed an expansile, osteolytic mass involving the rostral portion of the mandible. Mineralization of the soft-tissue component was evident. Rostral mandibulectomy was performed to remove the mass in its entirety. The histologic diagnosis was ameloblastic fibro-odontoma. One year after surgery, cosmetic appearance of the mandible was acceptable, and there was no evidence of tumor regrowth. Radiation therapy, cryotherapy, and thermocautery have been recommended in conjunction with surgical excision to prevent tumor regrowth in the oral cavity. Tumor regrowth was not a factor in long-term prognosis in this cow.

Twenty-two horses with ulnar fractures were treated, using tension band wires alone or tension band wires in combination with pins or cortical bone screws. Age of the horses ranged from 2 weeks to 12 years (median, 4 months), and body weight ranged from 68 to 477 kg (median, 181 kg). Fractures were classified according to the Donecker and Bramlage ulnar fracture classification and included type 1-a (4 horses), type 1-b (4), type-2 (6), type-3 (1), type-4 (3), and type-5 (4), fractures. Tension band wires alone were used in 7 horses. Tension band wires were used in conjunction with unthreaded pins in 10 horses. In 3 horses, 5.5-mm cortical bone screws were inserted longitudinally instead of pins. A combination of a 5.5-mm cortical bone screw and a pin was used in 2 horses. In addition to pins and tension band wires, 4.5-mm cortical bone screws were placed in lag fashion to aid reduction of comminuted or oblique fractures in 7 of the 22 horses. Fractures healed in 18 (82%) horses. Four horses were euthanatized because of complications that included catastrophic failure of fixation during recovery from general anesthesia in 1 foal, septic arthritis and hyperextension of the contralateral metacarpophalangeal joint in 1 foal, and wound infection with partial disruption of repair in 2 horses. Nonfatal complications developed in 6 horses and included incision infection, partial wound dehiscence, carpal contraction, carpus varus of the contralateral forelimb, slight distraction of proximal fragments of the fractures, bent implants, and distal migration of pins. Long-term monitoring was performed on 17 horses.(ABSTRACT TRUNCATED AT 250 WORDS)

Medical records of 40 racing Standardbreds with superficial digital flexor tendinitis that underwent transection of the accessory ligament of the superficial digital flexor (SDF) muscle (superior check desmotomy) were reviewed. Surgery was performed bilaterally in 32 horses and unilaterally in 8. Concurrent palmar annular desmotomy was performed in 8 horses in which tendinitis involved the distal metacarpal region and confinement of the deep and SDF tendons by the annular ligament was suspected. Follow-up information was obtained for 32 horses, by telephone, and racing results were available for 39 horses (1 horse is currently in training, but had a qualifying race prior to surgery). Tendinitis recurred in 8 of 32 (25%) horses that returned to training. Thirty-five of 38 (92%) horses started at least 1 race after surgery. Mean +/- SD time between surgery and first race was 237 +/- 86 days. Overall, 33 of 38 horses completed 5 or more races after surgery; however, SDF tendinitis recurred in 6, and treatment was, therefore, considered to be successful in 27 horses. Horses started a median of 18 races after surgery. Median amount of money won per start after surgery (median, $418; range, $0 to $4,626) was significantly less than median amount won per start before surgery (median, $1,155; range, $0 to $14,603). Inflammation of the interosseous muscle (suspensory ligament) developed in 5 horses with bilateral SDF tendinitis and in 2 horses with unilateral SDF tendinitis. All horses with inflammation of the interosseous muscle had undergone bilateral superior check desmotomy.

Tympany of the auditory tube diverticulum was treated in 2 Standardbred foals by fenestrating the median septum, using an endoscopically placed Nd:YAG laser. Recurrence in 1 foal was treated by enlarging the fenestration, using a modified Whitehouse approach, and the pharyngeal opening of the auditory tube. Use of the Nd:YAG laser eliminates the risk of inadvertent cranial nerve damage associated with incisions into the auditory tube diverticulum. The procedure can be performed with the horse sedated or anesthetized. Clinical signs can recur in the fenestration heals closed or if the condition is bilateral rather than unilateral.

Articular fracture of the dorsoproximolateral aspect of the third metatarsal bone (MT3) caused an acute onset of lameness in 5 horses; however, 3 of the horses had historical and radiographic or scintigraphic evidence of chronic tarsal and metatarsal disease before fracture. The pathogenesis of dorsoproximolateral fracture of MT3 remains unclear, but the fracture may occur as a result of the formation of abnormal bone in the proximal aspect of MT3. The prognosis for racing in horses with this fracture appears to be guarded.

Transoral axial division was performed, using endoscopic guidance, in 20 horses with epiglottic entrapment. Mean age of affected horses was 3 years (range, 2 to 5 years), and there were 18 Standardbreds and 2 Thoroughbreds. Standardbreds and female horses were significantly overrepresented when compared with a reference population. Upper respiratory noise prompted endoscopic examination before surgery in 16 horses, but noise was not heard in 4 horses. Ten horses had entrapment by thin tissue without ulceration, 6 horses had entrapment by thin tissue with small, partial-thickness ulceration, 3 horses had entrapment by moderately thick tissue with large, partial-thickness ulceration, and 1 horse had entrapment with thick tissue and severe ulceration. After surgery, horses received anti-inflammatory medication and box stall rest with hand walking for 7 days. All horses returned to race training on day 7 after surgery and returned to their previous level of racing or training. Epiglottic entrapment recurred in 2 horses (10%), and dorsal displacement of the palate developed in 2 horses after surgery. Relationship of epiglottic entrapment and dorsal displacement of the palate to epiglottic hypoplasia was not apparent. Transoral axial division under endoscopic guidance appeared to be a useful, safe, and economic alternative to currently available methods for management of epiglottic entrapment in horses. Horses with entrapment by thick and ulcerated tissue may be best managed by surgical resection of entrapping tissue.

Seven Standardbred horses, all pacers, with a mean age of 2.9 years (range, 2 to 4 years), had dorsomedial articular fracture of the proximal aspect of the third metacarpal bone. Fracture caused acute, unilateral, severe lameness after training or racing. Lameness was abolished by midcarpal joint anesthesia in 4 horses. Six horses had a palpable bony swelling, which caused signs of pain. Radiography revealed a nondisplaced, articular, oblique fracture extending distad toward the dorsomedial cortex for a mean distance of 28 mm (range, 15 to 40 mm). In all horses, chronic periosteal proliferative changes, seen near the distal aspect of the fracture, corresponded to palpable bony exostoses and were associated with the medial attachment of the extensor carpi radialis tendon. In 1 horse, internal fixation followed by a 6-month rest resulted in a successful outcome. All other horses were given 3 months' rest without surgery and were not lame. Five horses raced successfully and lowered the lifetime race records, 1 horse was sound and trained successfully, but died of colic, and 1 horse was not lame in early training.

Loop colostomy was performed in 10 horses as treatment for grade-III rectal tears (n = 6 horses), small-colon infarction (n = 2 horses), perirectal abscess and stenosis (n = 1 horse), and small-colon stricture (n = 1 horse). In 7 horses, the colostomy was constructed through a single incision low in the left flank, with closure of the incision around the stoma (single-incision technique). In 3 horses, 2 of which had colostomy performed as a standing procedure, the selected segment of small colon was placed from a flank incision into a separate, small incision low in the left flank (double-incision technique). Five horses underwent colostomy reversal (at 18 to 63 days) and 2 of these horses, both with grade-III rectal tears, recovered completely. Of 8 horses that did not survive, 6 died from the primary disease or associated complications. Technical problems associated with colostomy accounted for death of 2 horses. One horse had gastric rupture attributable to suture occlusion of the small intestine after colostomy reversal, and another horse had complications of incisional infection after repair of a peristomal hernia. Small-colon prolapse through the stoma necessitated premature reversal of the colostomy in a horse that was euthanatized because of worsening laminitis. Minor complications of the colostomy procedure were partial stomal dehiscence (n = 4 horses), partial dehiscence of the flank wound after colostomy reversal (n = 2 horses), and small ventral midline hernia after colostomy reversal (n = 1 horse). Loop colostomy may be of benefit to horses with rectal tears, provided it is done soon after the tear occurs.(ABSTRACT TRUNCATED AT 250 WORDS)

A 2-year-old Standardbred colt was examined because of signs of abdominal pain of 12 hours' duration. Clinical signs of disease, including tachycardia and abdominal distention, and rectal palpation findings of distention and thickening of the ventral colon, were consistent with displacement or early strangulation obstruction of the large colon. Surgical exploration revealed volvulus of the large colon around an axis formed by the dorsal mesenteric attachment of the transverse colon. The cecum could be completely exteriorized and lacked the cecocolic ligament and dorsal mesenteric attachments. The dorsal mesenteric attachments of the right ventral and dorsal colons were also lacking. The viscera were repositioned, and the horse was discharged 13 days after surgery. The horse developed severe colic 6 months later and was euthanatized. Mesenteric volvulus and omental adhesions were found at necropsy.

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.

Myoelectric activity of the ileum, cecum, and right ventral colon (RVC) was studied in 4 mature ponies. Eight Ag-AgCl bipolar recording electrodes were sutured to the seromuscular layer of the ileum (2 electrodes), cecum (4 electrodes), and RVC (2 electrodes). Myoelectric activity was studied beginning 10 days after surgery. Eight, 60-minute recording sessions were performed in each pony during the interdigestive period, which was the period 3 to 7 hours after the morning feeding. On separate days, food was withheld for 24 hours, and 90-minute recordings were obtained during the nonfeeding period. Ponies were then fed a normal ration, and recordings were continued to obtain data for the digestive (feeding) period. All phases of the migrating myoelectric complex were seen at both ileal electrodes during the interdigestive period, including the periods of no spiking activity (phase 1), irregular spiking activity (phase 2), and regular spiking activity (phase 3). Phase 2 occupied 77% of the total recording time, and the mean duration of phases 1, 2, and 3 was 3.4 +/- 0.2, 12.8 +/- 1.2, and 6.7 +/- 0.7 min, respectively. Frequency of ileal slow waves was 11.8 +/- 0.1/min, and spike burst conduction velocity was 4.7 +/- 0.3 cm/s. A complete migrating myoelectric complex was seen in 11 of 32 tracings (34%) and had a mean duration of 24.2 +/- 2.6 min. The ileal migrating action potential complex, most often seen in phase 2, had a frequency of 4.8 +/- 0.5 spike bursts/h and a conduction velocity of 13.6 +/- 0.4 cm/s.(ABSTRACT TRUNCATED AT 250 WORDS)

The case records of 26 horses with ileocecal intussusception over a 7-year period were reviewed to determine clinical features of the disease and response to treatment. The median age of horses with ileocecal intussusception was 1 year and ranged from 2 weeks to 19 years. There was no apparent gender or breed predisposition to this disease. An acute form of ileocecal intussusception was diagnosed in 19 horses with signs of moderate to severe abdominal pain of less than or equal to 24 hours' duration, and a chronic form was diagnosed in 7 horses with signs of intermittent, mild to moderate abdominal pain of more than 3 days' duration. Horses with chronic ileocecal intussusception had a history of weight loss or failure to gain weight, slow growth, poor appetite, low-grade pyrexia, and postprandial signs of abdominal pain. At surgery, the involved segments of intestine (intussusceptum and intussuscipiens) in chronic cases were 2 to 10 cm long, and the ileum and much of the distal portion of the jejunum were flaccid, dilated, and thick walled. In the acute cases, the length of involved intestine ranged from 6 to 457 cm. Whereas only 1 of 7 chronic intussusceptions (14%) could be reduced, 9 of 19 (47%) acute intussusceptions were reducible. Surgical treatment included resection and jejunocecostomy (6 horses), partial resection through a cecotomy and a side-to-side jejunocecostomy (2 horses), and a side-to-side ileocecostomy or jejunocecostomy without resection (12 horses, 7 of which had chronic intussusception). Six horses with acute intussusception were euthanatized before or during surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

A rapid and convenient commercial radioimmunoassay kit, developed for quantifying hormones in specimens from human beings, was validated for use in measuring insulin in serum of dogs, cattle, and horses. The procedure uses polypropylene assay tubes treated with rabbit anti-porcine insulin serum and porcine [125I]iodoinsulin. Specificity was proven by demonstrating that standard solutions of porcine insulin and serial dilutions of canine, bovine, and equine sera and pancreatic extracts inhibited binding of [125I]iodoinsulin to the antibody in a parallel manner. Gel-filtration chromatography of pancreatic extracts yielded a major peak of immunoreactive material that eluted identically with [125I]iodoinsulin. Immunoreactivity was not associated with fractions that contain larger and smaller molecular weight peptides (eg, proinsulin and C-peptide, respectively). Biological specificity of the assay was shown by demonstrating increased insulin in serum after injection of glucose into heifers and glucagon into dogs and horses. Purified insulin and insulin in pancreatic extracts could be quantitatively recovered from serum, thereby demonstrating accuracy of the assay. Interassay precision of 5 control specimens run in 20 consecutive assays ranged from 6.7% to 20.1% (coefficient of variation) and intra-assay precision of 6 control specimens each assayed 10 times ranged from 4.4% to 10.7% (coefficient of variation). Sensitivity of the assay was 3.2 microIU/ml. This radioimmunoassay for insulin is ideal for veterinary research and diagnosis, because a single set of reagents and procedures can be used for at least 3 species.

To study the normal motility of the cecum and right ventral colon (RVC) in 3 mature Shetland ponies, a 6-part, indwelling, intraluminal catheter system was used to measure intraluminal pressure changes. Three catheters were placed in the cecum at 10, 25, and 40 cm from the cecocolic orifice, and 3 catheters were placed in the RVC at 10, 20, and 30 cm from the cecocolic orifice. Recordings were made during the interdigestive period beginning 2 weeks after surgical operation was done. Frequent, low-amplitude peaks (0.35 +/- 0.13 coordinated peaks/min) were seen involving the cecal body and caudal cecal base, which represented a haustra-to-haustra mixing pattern. Coordinated pressure peaks originated in the cecal body and progressed to the cranial cecal base (0.07 +/- 0.01/min) or originated in the cranial cecal base and progressed to the cecal body (0.07 +/- 0.04/min). Associated with a loud rush of ingesta heard on transabdominal auscultation and progression of liquid ingesta confirmed with barium contrast radiography, there was a series of coordinated, progressive pressure peaks which originated in the cecal body, sequentially involved the cecal base, traversed the cecocolic orifice, and extended into the RVC (0.36 +/- 0.05/min). It seemed that a pacemaker region existed in the cecal body and initiated the important aborally propagated progressive pattern responsible for the transit of ingesta from the cecum to the RVC. A separate mechanism for the transit of gas was not identified. In the RVC, infrequent, nondirectional, low-amplitude segmental pressure peaks (0.12 +/- 0.06/min), and aborally progressive coordinated pressure peaks originating at the beginning of the RVC (0.09 +/- 0.02/min), occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Thirteen Standardbreds had subchondral lucency of the third carpal bone (C3), described as single or multiple central areas of C3 bone loss in the radial fossa. Sclerosis of the radial fossa was also detected. The mean age of 9 stallions, 3 mares, and 1 gelding was 4.1 years (range, 3 to 7 years). All horses had an acute moderate to severe lameness referable to the middle carpal joint. A dorsoproximal dorsodistal (skyline) radiographic projection was most useful and identified mild (3 horses), moderate (6 horses), and severe (4 horses) subchondral lucency and sclerosis of the radial fossa. The margin of C3 was intact dorsal to the lucent areas in all horses. In 12 horses, arthroscopic surgical evaluation and curettage of the lesion were performed. Of the 9 horses monitored long enough to allow racing, 8 horses (89%) returned to racing, although only 6 (75%) raced at the same degree of competition. Subchondral lucency of C3 resulted from chronic damage to C3 with subsequent osteochondral collapse or acute C3 proximal surface osteochondral fracture.

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 anastomosis site necessitated a second surgical procedure. Small colon intussusception is an uncommon cause of signs of abdominal pain and is similar to type-IV rectal prolapse.

The case records of 23 horses with cecal perforation (CP) were reviewed. The horses averaged 4.5 years of age (6 weeks to 13 years) and included 9 intact males, 12 mares, and 2 geldings. Twelve of the horses were Standardbreds, 9 were Thoroughbreds, and 1 each, a Belgian and Morgan. The horses were allotted to 2 groups: group I-13 hospitalized horses in which CP occurred unexpectedly, and group II-10 horses with CP at the time of admission. The horses characteristically had been sick or affected with disease unrelated to the cecum. Sixteen horses had been given nonsteroidal anti-inflammatory drugs before the onset of CP. Twelve of the 13 hospitalized patients (group I) had vague, scarcely recognizable clinical signs of gastrointestinal disease before CP. The clinical signs and clinical laboratory changes that appeared in affected horses were identifiable with severe endotoxin shock, secondary to peritoneal contamination with ingesta and bacteria. All horses died. At necropsy of the horses, the cecum was large and firm and was filled with ingesta, and the colon was empty; however, in 1 postpartum mare, the cecum and colon contained the usual amount of ingesta and were normal in size. In all horses, a single perforation was present, which appeared at various sites. The most common was a transverse perforation along the ventral aspect of the cecal body. Gross and microscopic examinations uncovered no existing disease near the perforation site or in other areas of the cecal wall or cecocolic orifice.(ABSTRACT TRUNCATED AT 250 WORDS)

The myoelectric activity of the cecum and right ventral colon (RVC) was studied in 4 female ponies. Eight, bipolar Ag-AgCl electrodes were sequentially placed on the seromuscular layer of the cecum (6 electrodes) and RVC (2 electrodes), and recordings were begun 14 days after surgery. The myoelectric activity for each pony was recorded during 12, 60-minute recording sessions done during the interdigestive period (3 to 7 hours after the morning feeding). Coordinated series of spike bursts were recognized as independent motility patterns in the cecum and in the RVC. Local haustra-haustra myoelectric activity involving approximately 40 cm of the cecal body (0.45 +/- 0.03 spike bursts/min) were detected. A series of spike bursts started at the cecal apex and progressed to, but stopped at, the caudal cecal base (0.40 +/- 0.03 spike bursts/min). Infrequently, a series of spike bursts started at the apex and progressed to the cranial cecal base (0.09 +/- 0.01 spike bursts/min). More commonly, a series of spike bursts with a conduction velocity of 3.8 +/- 0.07 cm/s, began in the cranial base and progressed orally to the cecal apex (0.46 +/- 0.03 spike bursts/min). Spike bursts conducted aborally (propulsion) beginning at the origin of the RVC (0.05 +/- 0.007 spike bursts/min) and spike bursts conducted orally (retropulsion; 0.15 +/- 0.02 spike bursts/min) were seen independent of cecal myoelectric activity. A progressive series of coordinated spike bursts, which began at the cecal apex, were conducted through the cecolic orifice and continued into the RVC (0.42 +/- 0.02 spike bursts/min), representing the only pattern common to the cecum and RVC.(ABSTRACT TRUNCATED AT 250 WORDS)

The medical records of 9 foals less than 4 months old, with fracture of the tibial diaphysis, were reviewed. Open reduction was accomplished by use of 3 approaches; however, a cranial approach was preferred and was used in 7 foals. Two dynamic compression plates were implanted in all foals except the first of this series. The technique of plate luting was used in 7 foals and appeared to improve the ability of implants to resist failure. Complications after surgery included partial or complete failure of fracture fixation (n = 3 foals), osteomyelitis (n = 2 foals), angular limb deformity (n = 2 foals), minor dehiscence of the surgical wound (n = 3 foals), and mild extensor deficits of the injured limb (n = 4 foals). One foal was euthanatized 12 hours after surgery because of complete loss of fracture fixation. All other foals were discharged 10 to 295 days after surgery. One or both plates were subsequently removed in 7 foals. Follow-up information was obtained 6 to 36 months after discharge. Excellent results were reported for 6 foals, and good or fair results were reported for the remaining 2 foals.

Four Holstein heifers were found to have partial nasal obstruction caused by bilateral cystic conchae. Three of the heifers (age range, 4 to 6 months) had a history of progressive nasal obstruction since near birth, were affected severely, and required surgical management. Each of 2 surgical procedures, a bilateral dorsolateral nasal flap approach and a dorsal nasal flap approach, was used successfully. The fourth heifer, which was 15 months old, had signs of nasal obstruction since shortly after birth, but was affected only mildly and was not treated. Follow-up information obtained 10 to 37 months later revealed that all cattle were considered normal and had no signs of nasal obstruction. In each case, a developmental problem or malformation of the ventral nasal concha resulting in cystic enlargement was suspected. The onset of clinical signs early in life and the bilateral nature suggested that the defect was of congenital origin.

Effects of xylazine HCl (0.5 mg/kg of body weight, IV) and/or butorphanol tartrate (0.04 mg/kg, IV) or neostigmine methylsulfate (0.022 mg/kg, IV) on myoelectric activity of the cecum and right ventral colon were studied in 4 conscious female ponies. Eight bipolar Ag/AgCl electrodes were sequentially placed on the seromuscular layer of the cecum (6 electrodes) and right ventral colon (2 electrodes). Recordings began 30 minutes before and continued for 90 minutes after drug administration. Each drug or drug combination was studied on 2 occasions in each pony. Two major patterns of coordinated spike bursts were identified. A series of coordinated spike bursts began at the cecal base and was conducted to the cecal apex (pattern I). A series of coordinated spike bursts began at the cecal apex, traversed the cecum, cecocolic orifice, and right ventral colon and was termed a progressive pattern (pattern II). Xylazine administration caused a significant decrease in patterns I and II for 20 minutes (P less than 0.05). Butorphanol tartrate administration caused a significant decrease in the progressive pattern for 10 minutes (P less than 0.05) without affecting the orally directed pattern. Administration of the combination of xylazine/butorphanol significantly decreased the frequency of pattern I for 40 minutes (P less than 0.05) and pattern II for 30 minutes (P less than 0.05). Neostigmine administration caused a significant increase in the frequency of pattern II for 30 minutes (P less than 0.05) without affecting pattern I (P greater than 0.05). Changes in conduction velocity of pattern I or II or the duration of spiking activity were not significantly different because of any treatment.

To study communications and boundaries of the middle carpal and carpometacarpal joints of the horse, 50 forelimbs were obtained from fresh cadaver specimens. Blue latex solution (20 +/- 2.5 ml) was injected into the middle carpal joint, and the specimens were frozen in extension. Frozen specimens were cut into 1-cm sagittal sections from the middle of the radius to the middle of the metacarpus. The communications between the middle carpal and carpometacarpal joints and the presence, length, and position of the distopalmar outpouchings of the carpometacarpal joint were recorded. The middle carpal and carpometacarpal joints always communicated between os carpale III (C3) and os carpale IV (C4). An additional communication between the joints existed in 17 (34%) of the specimens, 10 on the palmar aspect of C4, and 3 on the palmar aspect of os carpale II (C2). When os carpale I (C1) was present (n = 5), communication between C1 and C2 was observed in 4 of the 5 specimens. In all specimens, medial and lateral distopalmar outpouchings of the carpometacarpal joint were observed and were located between the axial surface of os metacarpale II (MC2) and os metacarpale IV (MC4) and the abaxial surface of the suspensory ligament. There was no significant difference between the lengths of the lateral (2.3 +/- 0.54 cm) or medial (2.6 +/- 0.75 cm) distopalmar outpouchings. Small extensions from the distopalmar outpouchings were seen and extended axially into the fibers of the suspensory ligament or between the suspensory ligament and the distal accessory ligament of the deep digital flexor tendon.(ABSTRACT TRUNCATED AT 250 WORDS)

Two yearling heifers developed rapidly growing soft tissue masses attached to the base of the right hind teat. In each heifer, the solitary mass was raised, firm, and attached to the overlying skin. En bloc removal was accomplished in each by positioning the heifer in dorsal recumbency and by using local infiltration analgesia. Histologic examination revealed one of the masses to be fibroma and the other, fibrosarcoma. Neither tumor has recurred, and normal function of the teat was retained.

A 3-year-old Standardbred stallion was admitted for treatment of acute enterocolitis. The horse improved in response to empiric treatment, but subsequently developed ventral edema, scrotal abscessation, and severe laminitis. Improvement again was seen, but on day 29 of hospitalization, the horse developed rapid heart rate and signs of abdominal pain. Exploratory celiotomy revealed complete obstruction of the descending portion of the duodenum, 20 cm caudal to the duodenal sigmoidal flexure. Three-tier duodenojejunostomy and jejunojejunostomy were performed to bypass the duodenal obstruction.