Analgesic effects of epidural administration of hydromorphone in horses

OBJECTIVE: To evaluate the effects of epidural administration of hydromorphone on avoidance threshold to noxious electrical stimulation of the perineal, sacral, lumbar, and thoracic regions in horses. ANIMALS: 6 healthy adult horses. PROCEDURE: Horses were assigned to receive hydromorphone (0.04 mg/kg) or a control solution (20 mL of sterile water) administered epidurally into in the first intercoccygeal space. Treatments were administered at time intervals of > or = 7 days. Electrical stimulation was applied for 6 hours after epidural injection over the dermatomes of the perineal, sacral, lumbar, and thoracic regions, and the avoidance threshold voltage was recorded. RESULTS: Administration of sterile water did not change the avoidance threshold. Hydromorphone significantly increased the avoidance threshold by 20 minutes after injection, which lasted until 250 minutes after epidural administration in the perineal, sacral, lumbar, and thoracic regions. Profound analgesia (avoidance threshold > 40 V) was achieved only in the perineal region at 60 minutes after epidural administration of hydromorphone. Analgesia for all dermatomes was considered moderate for 250 minutes after epidural injection. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural administration of hydromorphone increases the avoidance threshold to noxious electrical stimulation in the perineal, lumbar, sacral, and thoracic regions in horses for 250 minutes after injection. Hydromorphone epidural administration may prove useful in the management of horses with pain of moderate to mild intensity.     

Outcome of epidural catheterization for delivery of analgesics in horses: 43 cases (1998-2001)

OBJECTIVE: To determine reasons for epidural catheter placement among horses examined at a veterinary teaching hospital, efficacy of epidural administration of analgesics, duration of catheter placement, reasons for catheter removal, and complications encountered. DESIGN: Retrospective study. ANIMALS: 43 horses. PROCEDURE: Medical records were reviewed. RESULTS: A total of 50 epidural catheters were placed in the 43 horses. Underlying conditions included fractures, lacerations, septic arthritis, myositis, perineal injuries, and cellulitis. Horses ranged from 2 to 21 years old and weighed between 365 and 795 kg (803 and 1,749 lb). Median duration of catheter placement was 96 hours (range, 1.5 to 480 hours). The response to epidural drug administration was reported as positive in 34 horses and negative in 4. There was no apparent response in 2 horses, and response could not be determined in 3. Three temporary patient-related complications associated with epidural catheter administration were observed. Technical problems associated with the epidural catheters included dislodgement of the catheter itself (7 catheters) or of the adapter or filter (5), obstruction (5), and leakage (5). Twenty-two catheters were removed because of resolution of the underlying condition, and 10 were removed because of complications. For 6 catheters, the reason for catheter removal was not recorded. The remaining 12 catheters were in place when the horses were euthanatized. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that epidural catheterization can be used successfully for repeated epidural delivery of analgesics and anesthetics in horses with various clinical conditions. Complications associated with epidural catheters or epidural drug administration were infrequent and transient.     

Efficacy of an Epidural Combination of Morphine and Detomidine in Alleviating Experimentally Induced Hindlimb Lameness in Horses

Amphotericin B-induced synovitis of the left tarsocrural joint was used to create a grade 3 of 4 lameness in 11 horses. Caudal epidural catheters were placed and advanced to the lumbosacral region. Baseline heart and respiratory rates were recorded and horses were videotaped at a walk and trot. Morphine sulphate (0.2 mg/kg) and detomidine hydrochloride (30 μg/kg) were administered to treated horses (n = 8) through the epidural catheter; an equivalent volume of physiologic saline solution was administered to control horses (n = 3) through the catheter. At hourly intervals after epidural injection for a total of 6 hours, heart and respiratory rates were recorded, and horses were videotaped walking and trotting. At the end of the observation period, video recordings were scrambled onto a master videotape. Lamenesses were scored by three investigators unaware of group assignment or treatment time. Lameness scores, heart rates, and respiratory rates were compared between groups using repeated measures analysis of variance. There was a significant decrease in lameness score after treatment with epidural morphine and detomidine ( P =.0003); average lameness scores of treated horses were less than grade 1 at each hourly observation for 6 hours after drug administration. Early in the observation period, heart rates significantly increased in control horses and decreased in treated horses ( P =.03). A similar trend occurred for respiratory rates ( P =.07). Results of this study demonstrate that epidural administration of a combination of morphine and detomidine is capable of providing profound hindlimb analgesia in horses.     

The clinical, cerebrospinal fluid, and histopathologic effects of epidural ketorolac in dogs

OBJECTIVE: To evaluate the clinical, cerebrospinal fluid (CSF), and histopathologic effects of epidural ketorolac. STUDY DESIGN: Blinded, randomized, placebo controlled study. ANIMALS: Twenty-two adult mixed breed dogs with 16 treatment and 6 control dogs, weighing 14.4 to 29.8 kg. METHODS: Dogs were anesthetized and epidural catheters were placed at the lumbosacral space. Catheter placement was evaluated fluoroscopically. Ketorolac (0.4 mg/kg) or placebo (5% ethanol) was administered epidurally over a 52-hour period, with 5 injections given at 12-hour intervals. At 1, 2, 4, or 8 hours after the first and last injection of ketorolac, dogs were anesthetized and CSF was obtained. Control dogs had CSF sampled 1 hour after the first and last ethanol injection. Neurologic function and pain responses were evaluated before and during the study. Selected dogs were then killed and necropsies performed. RESULTS: None of the dogs exhibited any clinical or neurologic abnormalities during the study. No statistical difference was noted in pain response or CSF analysis between treatment and control dogs. Gross necropsy revealed gastrointestinal ulceration of varying degrees in all treatment dogs. Histopathologic analysis of the spinal cord and meninges revealed minimal focal leptomeningeal phlebitis in 2 of 8 treatment dogs and minor subdural inflammation in 1 control dog. No changes to the neural structures were noted in any dogs. CONCLUSIONS: Epidural administration of ketorolac did not cause clinical signs, alteration in CSF values, or pathologic changes to the spinal cord when used for short duration. Gastrointestinal ulceration was common when ketorolac was administered epidurally at 0.4 mg/kg every 12 hours for 5 treatments. CLINICAL RELEVANCE: This study documented the neurologic safety of epidural ketorolac in dogs before an efficacy trial can be performed. Gastrointestinal ulceration may limit use to short duration or a single injection.     

Comparison of cervical epidural morphine with intravenous morphine administration on antinociception in adult horses using thermal threshold testing

ObjectiveTo compare the antinociceptive effects of morphine administered via cervical epidural catheter to intravenously administered morphine using a thermal threshold (TT) testing model in healthy adult horses.Study designProspective, randomized, blinded experimental study.AnimalsA total of six university-owned adult horses.MethodsHorses were instrumented with a cervical (C1–C2) epidural catheter and TT testing device with probes at withers and thoracic limb coronary bands. All horses underwent three TT testing cycles including cervical epidural morphine administration (treatment EpiM; 0.1 mg kg^–1), systemic morphine administration (treatment SystM; 0.1 mg kg^–1) and no morphine administration (treatment Control). Baseline TT was established prior to treatments, and TT was tested at 15, 30, 60, 90, 120, 150, 180, 240, 300, 360, 420, 480, 600 and 720 minutes following treatment. Horses underwent a 5 day washout period between treatments and the order of treatment was randomized. Differences between treatments were analyzed with repeated measures anova.ResultsSystemic and epidural morphine administration resulted in significantly higher TT values compared with baseline and control treatment. The duration of effect was significantly longer in treatment EpiM (10–12 hours) than in treatment SystM (1.5–2.0 hours). Horses in treatment EpiM had significantly higher TT values at time points 180–600 minutes (withers) and 300–600 minutes (coronary band) than horses in treatment SystM.Conclusions and clinical relevanceCervical epidural administration of morphine provided antinociceptive effects as measured by increased TT for 10–12 hours compared with 1.5–2.0 hours for intravenously administered morphine. No complications or adverse effects were noticed following epidural placement of a C1–C2 catheter and administration of morphine. The use of a cervical epidural catheter can be considered for analgesia administration in treatment of thoracic limb and cervical pain in the horse.     

Airway mucus in recurrent airway obstruction--short-term response to environmental challenge

Mucus accumulation and neutrophilic inflammation in the airways are hallmarks of heaves. Endoscopically visible mucus accumulations, however, have not been studied during exposure to dusty hay and allergens (ie, environmental challenge). We hypothesized that (1) heaves-affected horses have increased mucus accumulation compared with controls, (2) mucus accumulations increase in heaves-affected horses during environmental challenge, and (3) environmental challenge also induces neutrophilic inflammation and mucus accumulation in control horses. Mucus accumulation was graded endoscopically (mucus grades [MGs] 1-5), and airway inflammation was evaluated by bronchoalveolar lavage fluid (BALF) cytology before (0 hours) and during (6, 24, 48 hours) environmental challenge. Large amounts of mucus (MG 4-5) were specific for heaves-affected horses in this study. Variation among controls was considerable, however, and intermediate grades (MG 2-3) were nonspecific, showing complete overlap between the 2 groups. Median mucus accumulations (25th, 75th percentiles) increased in heaves-affected horses from MG 2.5 (1.5, 3.5) at baseline to MG 3.5 (2.0, 4.0), 4.0 (3.0, 4.0), and 4.0 (4.0, 4.0) at 6, 24, and 48 hours, respectively. MG values did not increase in controls--overall MG 1.0 (1.0, 2.0)--even though controls also showed a moderate increase of BALF neutrophils. Mucus accumulations before and especially after exposure to dust and allergens are increased in heaves-affected horses compared with controls. Healthy controls show considerable variability in mucus accumulation but, despite an influx of neutrophils into the airways, no increase of mucus accumulation after exposure to hay dust.     

A comparison of the analgesic effects of caudal epidural methadone and lidocaine in the horse

Objective To evaluate and compare the effects of caudal epidural administration of methadone (METH) and lidocaine (LIDO) on tolerance to thermal stimulation over the dermatomes of the perineal, sacral, lumbar and thoracic regions in the horse. Study design A blinded, randomized, prospective, experimental cross‐over study. Animals Seven healthy horses, 15.7 ± 4.9 years (mean ± SD) of age, weighing 536 ± 37 kg. Methods The horses were randomly assigned to receive two treatments (group M: METH, 0.1 mg kg^?1 or group L: LIDO, 0.35 mg kg^?1) at intervals of at least 28 days. An 18‐gauge 80‐mm Tuohy epidural needle was placed in the first intercoccygeal space (Co1–Co2) in awake standing horses restrained in stocks. Analgesia was assessed by use of a probe maintained at a constant 62 °C by circulating hot water. The maximum stimulation time was 30 seconds. Bilateral stimulation was performed at five defined points. Before drug administration, baseline values of response time to thermal stimuli were obtained. Time to response was then measured 15 and 60 minutes after METH or LIDO administration and then hourly until the response returned to baseline at all stimulation points on two further assessments. Development of any ataxia and/or sedation was recorded. Positive pain responses were defined as purposeful avoidance movements of the head, neck, trunk, limbs and tail. Absence of attempts to kick, bite and turning of the head toward the stimulation site were used to indicate analgesia. Results Caudal epidural administration of METH and LIDO significantly increased reaction time to thermal stimulation (one‐sample t‐test; p = 0.05). Analgesia in the perineal region was present 15 minutes after both METH and LIDO administration and progressed from caudal to cranial dermatones with time. The duration of a significant increase in reaction time was 5 hours after METH injection compared to 3 hours following LIDO. All horses defaecated and urinated normally, and no excitement, sedation or ataxia were observed after METH administration. The horses were unable to defaecate normally and were moderately to severely ataxic with hindlimb weakness after LIDO. Conclusions Caudal epidural administration of methadone has considerable potential in the management of perineal, lumbo‐sacral and thoracic pain in horses. Regional differences exist in the onset, duration and intensity of the pain relief. Clinical relevance Epidural methadone administration provides analgesia with no measured side effects in these healthy adult horses.     

Cardiopulmonary effects of epidurally administered xylazine in the horse

This study was designed to determine whether the epidural administration of an alpha2 agonist, xylazine, would produce measurable changes in arterial blood pressure, electrocardiographic (ECG) activity and arterial blood gas values in horses. Six horses were given each of four treatments: epidural xylazine, intravenous xylazine, epidural lidocaine and epidural saline. A carotid artery catheter was used to measure arterial blood pressure and to collect samples for blood gas analysis before treatment and at intervals post treatment. Heart rate, arterial pressures, ECG activity and respiratory rate were recorded at the same intervals. No significant changes were recorded between time intervals or between individual treatments. It was concluded that this method of xylazine administration to horses produced potent caudal analgesia without measurable cardiopulmonary effects.     

Effects of enteral and intravenous fluid therapy, magnesium sulfate, and sodium sulfate on colonic contents and feces in horses

OBJECTIVE: To assess changes in systemic hydration, concentrations of electrolytes in plasma, hydration of colonic contents and feces, and gastrointestinal transit in horses treated with IV fluid therapy or enteral administration of magnesium sulfate (MgSO4), sodium sulfate (NaSO4), water, or a balanced electrolyte solution. ANIMALS: 7 horses with fistulas in the right dorsal colon (RDC). PROCEDURE: In a crossover design, horses alternately received 1 of 6 treatments: no treatment (control); IV fluid therapy with lactated Ringer's solution; or enteral administration of MgSO4, Na2SO4, water, or a balanced electrolyte solution via nasogastric intubation. Physical examinations were performed and samples of blood, RDC contents, and feces were collected every 6 hours during the 48 hour-observation period. Horses were muzzled for the initial 24 hours but had access to water ad libitum. Horses had access to hay, salt, and water ad libitum for the last 24 hours. RESULTS: Enteral administration of a balanced electrolyte solution and Na2SO4 were the best treatments for promoting hydration of RDC contents, followed by water. Sodium sulfate was the best treatment for promoting fecal hydration, followed by MgSO4 and the balanced electrolyte solution. Sodium sulfate caused hypocalcemia and hypernatremia, and water caused hyponatremia. CONCLUSIONS AND CLINICAL RELEVANCE: Enteral administration of a balanced electrolyte solution promoted hydration of RDC contents and may be useful in horses with large colon impactions. Enteral administration of either Na2SO4 or water may promote hydration of RDC contents but can cause severe electrolyte imbalances.     

Evaluation of the analgesic effects of epidurally administered morphine, alfentanil, butorphanol, tramadol, and U50488H in horses

OBJECTIVE: To evaluate and compare effects of epidurally administered morphine, alfentanil, butorphanol, tramadol, and U50488H on avoidance threshold to noxious electrical stimulation over the dermatomes of the perineal, sacral, lumbar, and thoracic regions in horses. ANIMALS: 5 healthy adult horses. PROCEDURE: Using a Latin square complete repeated-measures design, horses were randomly assigned to receive 1 of 6 treatments (morphine, alfentanil, butorphanol, tramadol, U50488H, or sterile water) at intervals of at least 7 days. Agents were injected epidurally at the first intercoccygeal epidural space, and electrical stimulation was applied at repeated intervals for 24 hours to the dermatomes of the perineal, sacral, lumbar, and thoracic regions. Avoidance threshold to electrical stimulation was recorded. RESULTS: Administration of butorphanol, U50488H, and sterile water did not induce change in avoidance threshold. Alfentanil increased avoidance threshold during the first 4 hours, but not significantly. Tramadol and morphine significantly increased threshold and analgesic effects. Complete analgesia (avoidance threshold, >40 V) in the perineal and sacral areas was achieved 30 minutes after tramadol injection, compared with 6 hours after morphine injection. Duration of complete analgesia was 4 hours and 5 hours after tramadol and morphine injections, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural administration of tramadol and morphine induces long-lasting analgesia in healthy adult horses. Epidural administration of opioids may provide long-lasting analgesia in horses without excitation of the CNS.     

Concentrations of gentamicin in serum and bronchial lavage fluid after once-daily aerosol administration to horses for seven days

OBJECTIVE: To assess gentamicin concentrations in serum and bronchial lavage fluid (BLF) of horses during a 24-hour period after once-daily aerosol administration of gentamicin (GAER) for 7 days and the pattern and degree of bronchial tree inflammation associated with repeated GAER. ANIMALS: 13 healthy adult horses (9 geldings and 4 mares). PROCEDURE: The treatment group comprised 8 horses, and 5 horses were untreated control animals. Gentamicin (20 mL of gentamicin [50 mg/mL]) was administered via aerosol once daily for 7 days. Samples of serum and BLF were obtained from all horses before GAER and 0.5, 4, 8, and 24 hours after the final day of GAER. Gentamicin concentrations were determined for all samples from treated horses, and cytologic examinations were performed on all BLF samples. RESULTS: Peak median BLF gentamicin concentration detected at 0.5 hours was 2.50 microg/mL. Median serum gentamicin concentration was < 0.50 microg/mL at all time points. Significant differences were not observed in total nucleated cell counts or differential cell counts in BLF between groups at any time point. Neutrophil count in BLF for all horses was increased over baseline at 4 and 24 hours. CONCLUSIONS AND CLINICAL RELEVANCE: We did not detect evidence of gentamicin accumulation or respiratory inflammation after once-daily GAER for 7 days. This protocol appears unlikely to result in local or systemic toxicosis. Repeated daily GAER to horses appears to be a safe procedure and may have clinical use in the treatment of horses with bacterial infections of the airways.     

Epidural anesthesia and analgesia in horses.

Intercoccygeal, or caudal, epidural injection of local anesthetics is a convenient method of producing analgesia and local anesthesia of the tail and perineal structures in conscious standing horses. This technique has been further developed to provide long duration analgesia and anesthesia by placement of catheters into the epidural space of horses. More recently, opioid, alpha-2 adrenergic agonists, ketamine and other analgesic agents have been administered by caudal epidural injection, providing pain relief in both conscious, standing and anesthetized, recumbent horses. This chapter describes the development of different anesthetic and analgesic epidural techniques in horses, methods for epidural injection and catheterization, and reviews the current literature related to epidural analgesia and pain control in horses.     

Use of iohexol for myelography in the horse

The use of iohexol as a contrast agent for myelography is reported in two groups of horses. Group 1 (n = 6) were used only for myelography and to assess the clinical and pathological effects of intrathecal administration of iohexol. A volume of 20 ml at a concentration of 300 or 350 mg iodine/ml gave satisfactory myelographic detail with no serious clinical or neurological side effects. Only a minimal inflammatory response could be demonstrated in cerebrospinal fluid at four and 14 days after injection. At post mortem examination 14 days after myelography there was no evidence of meningitis nor was any other pathological change detected. Group 2 (n = 19) comprised a series of clinical cases of suspected cervical vertebral malformation. The only untoward sequelae recorded involved two horses in which iohexol was diluted with sterile water prior in intrathecal injection. A progressive necrotising meningitis developed in both cases which necessitated euthanasia. It was concluded that the major advantages of iohexol for use in the horse were its diagnostic quality, safety and low cost.     

Evaluation of a method of intracoelomic catheterization in koi

OBJECTIVE: To develop an easy and safe method for catheterization and determine the pharmacokinetics of a single dose of enrofloxacin after intracoelomic administration in koi. DESIGN: Prospective study. ANIMALS: 20 healthy koi. PROCEDURE: 6 koi were anesthetized with tricaine methanesulfonate, and a 23-gauge, three-fourths-inch butterfly catheter was inserted into the coelomic cavity and secured. Catheters were flushed daily for 6 days with 0.4 mL of sterile saline (0.9% NaCl) solution containing heparin (100 units of heparin in 250 mL of saline solution) without removing koi from the aquarium. At the end of the sixth day (144 hours), each of the 6 catheterized koi and 6 uncatheterized (control) koi was anesthetized individually. Enrofloxacin (10 mg/kg [4.5 mg/lb]) was administered to catheterized koi via the injection port and to control koi via a 23-gauge needle in the same site as the catheter placement. A pharmacokinetics study was performed on multiple plasma samples to validate the efficiency of the catheter. Reliability of the catheterization method was determined in 8 koi. RESULTS: All 6 catheters remained patent and effective for the 6 days prior to the start of the pharmacokinetics study. Results for the 2 routes of administration were comparable, and all koi survived the study without any detectable clinical problems. CONCLUSIONS AND CLINICAL RELEVANCE: An intracoelomic catheter was effective and safe when maintained in koi for at least 6 days. This would be highly beneficial for veterinarians, clients, and fish, especially when intracoelomic administration of a drug would require daily or more frequent dosing.     

Histologic findings in the gastrointestinal tract of horses with colic

Thirty horses were admitted to the University of Georgia Veterinary Medical Teaching Hospital with colic severe enough to warrant surgery and/or euthanasia. Gastrointestinal tracts of these 30 horses were histologically examined for morphologic changes. The horses were grouped according to cause of the colic (ie, simple obstruction, strangulation obstruction, thromboemboli, and inflammation). Lesions were graded as to severity, and grade scores were correlated with survival or nonsurvival. Mucosal changes developed distal and proximal to the primary lesion site and, although there were some differences between groups, changes characteristic of ischemia were common to all groups. The predictability of lesion grades of 2 or higher for nonsurvivability (90%) indicates that intestinal biopsy may have prognostic value in the postsurgical evaluation and management of equine colic.     

Diagnosis and surgical treatment of epidural neoplasms in two ataxic horses

Two cases of ataxia caused by epidural neoplasia diagnosed with myelography and histopathology are presented in this report. One horse was diagnosed with lymphohistiocytic lymphosarcoma and the other with haemangiosarcoma. In both cases, subtotal dorsal decompression was performed as part of their treatment protocol. One horse was subjected to euthanasia immediately after surgery; however, the other horse recovered well, with no gait abnormalities and a normal myelographic dye column seen at 6 months post surgery. Although both horses were ultimately subjected to euthanasia, subtotal dorsal decompression provides a potential surgical treatment for epidural neoplasia.     

Pulmonary and systemic effects of inhaled endotoxin in control and heaves horses

To investigate whether inhaled endotoxin contributes to airway inflammation and dysfunction in stabled horses, control (n = 6) and asymptomatic heaves (previously termed chronic obstructive pulmonary disease)-susceptible (n = 7) horses were given inhalation challenges with 20, 200 and 2,000 microg of soluble Salmonella typhimurium Ra60 lipopolysaccharide (LPS). LPS inhalation induced a dose-dependent neutrophilic airway inflammatory response in both groups. Inhalation with 2,000 microg of LPS also induced detectable lung dysfunction in the heaves group. LPS inhalation did not alter clinical score, tracheal secretion volume or airway reactivity in either group. The no-response thresholds were lower for the heaves group (<20 microg for airway inflammation; 200 to 2,000 microg for lung dysfunction) than for the control group (20 to 200 microg for airway inflammation; >2,000 microg for lung dysfunction). To enable comparison of these threshold levels with airborne endotoxin concentrations in stables, horses also received a 5 h duration hay/straw challenge, during which the total and respirable airborne endotoxin concentrations were determined. Comparison of the effects of acute LPS inhalation and hay/straw challenges suggest that inhaled endotoxin is not the sole cause of heaves. However, it is likely that it contributes to airway inflammation, both in heaves horses in concert with other inhalants, and in normal horses when they are exposed to high levels in poor stable environments.     

Surgical Reduction of Ileal Impactions in the Horse: 28 Cases

Objective —To evaluate the seasonal influence, signalment, type of hay consumed, clinical examination findings, and outcome after surgery for horses with ileal impaction. Study Design —A retrospective study. Results —Between 1988 and 1993, 28 horses had surgical correction of ileal impaction. There was a significantly higher rate of ileal impaction during the Fall (September-November, P= .0041). Mean duration of clinical signs of abdominal pain before referral was 15 hours. Transrectal palpation was used to localize the impaction in 11 horses. The ileal impaction was reduced by extraluminal massage aided by admixing of intestinal fluid oral to the impaction or injection of fluids intraluminally and then movement of the ingesta into the cecum alone in 24 horses. A total of 26 horses recovered from surgery; 24 horses were discharged from the hospital and eventually returned to previous use. Two horses had fatal postoperative complications: jejunocec-ostomy dehiscence and development of extensive small intestine adhesions after manual reduction of the impaction. One horse initially treated by manual reduction required jejunocecostomy twice for management of recurrent ileal impaction. Follow-up information was obtained for 21 horses, of which 20 were alive 1 year or longer after surgery. A total of 27 of 28 horses were fed Coastal Bermudagrass hay as the primary type of hay consumed. A total of 9 horses continued to be fed Coastal Bermudagrass hay as the only roughage source, whereas 6 horses were fed Coastal Bermudagrass with at least 50% other hay, and in 6 horses, Coastal Bermudagrass hay was entirely eliminated from the diet. Conclusion and Clinical Relevance—Ileal impactions can be successfully reduced by celiotomy and extraluminal massage and injection techniques to soften the ingesta for passage into the cecum without enterotomy or bypass techniques in most horses. Changes in weather and feeding practices in the Fall may account for an increased risk of ileal impaction in horses in the southeastern United States at that time of year.