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Objectives: To report the clinical presentation, complications, and long-term outcomes of cats treated for perineal hernia with modified internal obturator muscle transposition., Methods: The medical records of cats surgically treated for perineal hernia between 2013 and 2019 were reviewed and an owner questionnaire was conducted to determine long-term outcome., Results: Thirty-six cats were included in the study: 34 had bilateral and two unilateral hernias. Of these 36, 24 (67%) were male neutered with a median age of 10 (range: 1 to 18) years. The complication rate was low, however, one cat experienced a major postoperative complication: rectal prolapse requiring revision surgery 48 hours postsurgery. Short-term outcomes were available for 32 of 36 (89%) cats. Of the 32, 23 were examined 6 weeks postoperatively, and a telephonic consultation was performed for an additional nine of 32. Of the 23 cats examined directly, none had recurrence. Overall 12 of 32 experienced short-term postoperative tenesmus which resolved in nine of 12 (75%). Long-term outcomes were available for 31 of 36 cats (86%), with a median of 18.5 (6 to 89) months follow-up. A good outcome was achieved in 23 of 31 (74%) whereas three of 31 (10%) had fair outcomes and five of 31 (16%) had a poor outcome. Of the five cats with a poor outcome, two required subtotal colectomy to manage clinical signs related to megacolon, two were euthanised following a return of clinical signs, and one developed unilateral recurrence., Clinical Significance: Perineal hernia should be considered in cats presenting with tenesmus or recurrent obstipation. Surgical treatment of perineal hernias in cats can result in good owner-assessed long-term outcome., (© 2022 British Small Animal Veterinary Association.)

Objective: To evaluate outcomes in cats undergoing subtotal colectomy for the treatment of idiopathic megacolon and to determine whether removal versus nonremoval of the ileocecocolic junction (ICJ) was associated with differences in outcome., Animals: 166 client-owned cats., Procedures: For this retrospective cohort study, medical records databases of 18 participating veterinary hospitals were searched to identify records of cats with idiopathic megacolon treated by subtotal colectomy from January 2000 to December 2018. Data collection included perioperative and surgical variables, complications, outcome, and owner perception of the procedure. Data were analyzed for associations with outcomes of interest, and Kaplan-Meier survival time analysis was performed., Results: Major perioperative complications occurred in 9.9% (15/151) of cats, and 14% (12/87) of cats died as a direct result of treatment or complications of megacolon. The median survival time was not reached. Cats with (vs without) a body condition score < 4/9 (hazard ratio [HR], 5.97), preexisting heart disease (HR, 3.21), major perioperative complications (HR, 27.8), or long-term postoperative liquid feces (HR, 10.4) had greater hazard of shorter survival time. Constipation recurrence occurred in 32% (24/74) of cats at a median time of 344 days and was not associated with retention versus removal of the ICJ; however, ICJ removal was associated with long-term liquid feces (OR, 3.45), and a fair or poor outcome on owner assessment (OR, 3.6)., Conclusions and Clinical Relevance: Results indicated that subtotal colectomy was associated with long survival times and a high rate of owner satisfaction. Removal of the ICJ was associated with less favorable outcomes in cats of the present study.

Objective: To compare survival and complications in horses undergoing large colon resection with either sutured end-to-end or stapled functional end-to-end anastomoses., Study Design: Retrospective cohort study., Animals: Twenty-six client-owned horses with gastrointestinal disease., Methods: Retrospective data were retrieved from the medical records of 26 horses undergoing colectomy, including 14 horses with sutured end-to-end and 12 horses with stapled functional end-to-end anastomoses, between 2003 and 2016. Records were evaluated for signalment, medical and surgical treatments, and survival to hospital discharge. Long-term follow-up was obtained through owner contact. Continuous variables were compared with Mann-Whitney tests. Fisher's exact testing was used to compare survival to hospital discharge. Survival time was compared by constructing Kaplan-Meier survival curves and performing log-rank curve comparison testing., Results: Mean age of horses undergoing colectomy was 13 years. Reason for colectomy was prophylaxis (12) or salvage (14). Mean surgical time was 169 minutes. Mean hospitalization time was 9 days, which did not differ with anastomosis type (P = .62). Nine of 12 horses undergoing stapled functional end-to-end anastomosis and 12 of 14 horses undergoing sutured end-to-end anastomosis survived to hospital discharge (P = .63). Survival time did not differ with anastomosis technique (P = .35)., Conclusion: Short- and long-term survival outcomes are not different between sutured end-to-end or stapled functional end-to-end anastomoses in horses undergoing colectomy., (© 2017 The American College of Veterinary Surgeons.)

Bioabsorbable hemostatic agents such as oxidized regenerated cellulose are widely used to control intraoperative diffuse capillary bleeding. Compared with electrocautery or ligation, oxidized regenerated cellulose has the advantage of controlling bleeding without occluding the vessel lumen or causing thermal injuries to adjacent tissue. Although the manufacturer recommends removal of the material once hemostasis is achieved, oxidized regenerated cellulose is a bioabsorbable hemostatic agent and is often left in the surgical bed to prevent subsequent bleeding after surgical closure. However, noninvasive imaging techniques have revealed granulomatous foreign-body reactions that mimic infection or tumor recurrence. We present a case report of sterile peritonitis and granuloma formation secondary to the presence of oxidized regenerated cellulose after intestinal resection to excise a colonic adenocarcinoma in an aged rhesus macaque.

Feline colonic adenocarcinoma is a locally invasive, highly metastatic tumor that is most often treated with wide surgical excision (subtotal colectomy) and systemic chemotherapy either with or without nonsteroidal anti-inflammatory medications. In this retrospective study, the outcome of subtotal colectomy and adjuvant carboplatin in 18 client-owned cats is described. The median carboplatin dose was 200 mg/m(2) (range, 200-254 mg/m(2)) q 4 wk with a median of five doses/cat (range was two to seven doses/cat). Limited toxicities were noted. Positive prognostic factors for the disease-free interval included cats that had weight loss as a presenting sign (P < 0.036) and negative prognostic factors for median survival included nodal and distant metastasis (178 versus 328 days and 200 versus 340 days, respectively). The median disease-free interval was 251 days (range, 37-528 days) and the median survival time was 269 days (range, 40-533 days). Subtotal colectomy and adjuvant carboplatin is a safe and potentially effective treatment for cats with colonic adenocarcinoma.

Surgical management of idiopathic megacolon is described in 2 cats by a rectal pull-through with subtotal colectomy performed outside of the abdomen. This newly described technique facilitates access to the rectum for suturing an anastamosis without the need for pubic osteotomy and with minimal risk of abdominal contamination.

Objectives: To evaluate the long-term results of subtotal colectomy for acquired hypertrophic megacolon in the dog., Methods: Eight dogs with acquired hypertrophic megacolon underwent subtotal colectomy with preservation of the ileocolic junction. Long-term follow-up was obtained by clinical records and telephone interviews with the owners., Results: Eight large-breed dogs (age range: 6 to 12 years; mean age: 10.75 years) were enrolled. The use of bone meal, low levels of exercise, chronic constipation with dyschesia and tenesmus refractory to medical management were factors predisposing dogs to acquired hypertrophic megacolon. The diagnosis was confirmed in all animals by abdominal palpation, plain radiography and postoperative histopathological findings. There were no intraoperative complications. One dog died as a result of septic peritonitis. The clinical conditions (that is, resolution of obstipation and stool consistency) of the remaining seven dogs were improved at discharge; all animals returned to normal defecation in five to 10 weeks (mean: 7.3 weeks) and were alive 11 to 48 months (mean: 40.5 months) after surgery., Clinical Significance: Predominantly bony diet and/or low levels of physical activity may predispose dogs to acquired hypertrophic megacolon. Our results emphasise the long-term effectiveness of subtotal colectomy with preservation of the ileocolic junction in this condition.

An 11-year-old, female neutered Labrador retriever was presented with a micro-invasive differentiated papillar adenocarcinoma at the colorectal junction. A colorectal end-to-end anastomosis stapler device was used to perform resection and anastomosis using a transanal technique. A rectovaginal fistula was diagnosed two days later. An exploratory laparotomy was conducted and the fistula was identified and closed. Early dehiscence of the colon was also suspected and another colorectal anastomosis was performed using a manual technique. Comparison to a conventional manual technique of intestinal surgery showed that the use of an automatic staple device was quicker and easier. To the authors' knowledge, this is the first report of a rectovaginal fistula occurring after end-to-end anastomosis stapler colorectal resection-anastomosis in the dog. To minimise the risk of this potential complication associated with the limited surgical visibility, adequate tissue retraction and inspection of the anastomosis site are essential.

Objective: To report use of a biofragmentable anastomosis ring (BAR) device in cats with idiopathic megacolon (FIM) and compare outcome after subtotal colectomy with sutured colocolic anastomosis., Study Design: Retrospective study., Animals: Nineteen cats with megacolon., Methods: Medical records (January 1990-January 2004) of cats treated surgically for idiopathic megacolon with sutured (SUT) or BAR anastomosis were retrieved and reviewed. Operative, short- and long-term complications, and survival times were recorded and Kaplan-Meier survival analysis used to assess outcome., Results: There were 11 SUT and 8 BAR cats. One BAR cat had anastomotic dehiscence 36 hours after surgery. Mild serosal tearing during BAR insertion in 6 cats was corrected by suture reinforcement. One SUT cat developed anastomotic stricture at 32 days. Short-term complication rates at 3 and 7 days were 18% and 45% in the SUT group and 25% and 87.5% in the BAR group, respectively (P=.058). Two SUT cats had persistent loose stool consistency and were euthanatized 254 and 1661 days after surgery. One BAR cat had recurrence of constipation which was managed medically. Long-term complication rates were not significantly different between SUT and BAR (P=.61). The 1 and 4-year survival rates were 90% for SUT and 100% for BAR (P=.29)., Conclusions: No difference was detected for short and long-term complication rates and survival times between SUT and BAR groups., Clinical Relevance: The BAR device can be used for colocolic anastomosis in cats with idiopathic megacolon. Serosal tearing during BAR insertion was a common intraoperative complication. Regardless of anastomotic technique, survival outcome after colonic resection is excellent for cats with FIM.

There are many recognised causes of constipation in the cat and the management of the condition depends on the clinician's ability to recognise the appropriate aetiology in each case. Most surgery therapies for constipation in the cat are related to the management of idiopathic megacolon, although causes such as pelvic outlet obstruction, complications of neutering surgery, perineal herniation, and malunion pelvic fractures may also require surgical intervention. Currently, the surgical management of megacolon consists of subtotal colectomy with the recommendation that the ileocolic junction be preserved. The procedure, in general, is associated with few life-threatening complications although the majority of individuals will experience a transient period of loose stool formation in the immediate post-operative period. In the majority of cases, the long-term outcome following subtotal colectomy is considered excellent., (Copyright 2002 ESFM and AAFP)

A 14-year-old 61.7-kg (136-lb) alpaca was examined for colic of 24 hours' duration. An exploratory celiotomy was performed because of lack of response to medical treatment and ultrasonography revealed an abnormally large amount of free fluid in the peritoneal cavity. Exploration of the abdomen revealed a 20-cm diameter mass, consisting of most of the ascending colon. The spiral colon was thick and edemetous, and it was decided to resect the spiral colon. Following a few complications, the alpaca was discharged 17 days after surgery. Colic in camelids is considered a severe problem because clinical signs are subtle and often not recognized until the condition is untreatable. Camelids are reported to be stoic animals, and may have few signs of pain despite severe abdominal disease. Alpacas with signs of abdominal pain should undergo early and complete physical, laboratory, and diagnostic imaging evaluations. Rapid identification of the need for surgery is vital for a successful outcome.

A 7-month-old sexually intact female Vietnamese pot-bellied pig was evaluated because of constipation. On abdominal palpation, a hard tubular structure was palpated in the middle of the abdomen. Abdominal radiography revealed loops of intestine that were markedly distended with ingesta, consistent with obstructive intestinal disease. On exploratory celiotomy, a massively distended cecum and spiral colon were found. A subtotal colectomy, with a side-to-side ileocolonic anastomosis, was performed. The cause of the megacolon was not discovered. The pig did well following surgery and eventually defecated normally following an initial period of diarrhea. To our knowledge, this is the first report of therapeutic removal of a substantial portion of the large intestine in swine. Our decisions concerning the pig of this report were based largely on our knowledge of megacolon in cats. The outcome for this pig indicates that subtotal colectomy along with removal of the cecum and ileocecal valve can be used to successfully treat idiopathic megacolon in Vietnamese pot-bellied pigs.

Objective: To evaluate a group of cats with malignant colonic neoplasia and to identify factors related to survival time., Design: Retrospective study., Animals: 46 cats with malignant colonic neoplasia., Procedure: Information on signalment, diagnostic findings, histopathologic diagnosis, surgical procedure performed, identification of nodal metastasis at surgery, type of chemotherapy administered, and survival time was obtained from the medical record of each cat. A diagnosis of malignant colonic neoplasia had been established by histologic examination of endoscopic biopsy specimens (3 cats), biopsy specimens obtained during laparotomy (38), or necropsy specimens (5)., Results: Mean age of cats was 12.5 years (range, 6 to 18 years). Ultrasonography was useful 84% of the time in localizing the mass to the intestine. Three cats had endoscopic biopsy, 9 had incisional biopsy, 21 had mass resection, and 8 had subtotal colectomy performed. Histopathologic diagnoses included adenocarcinoma (21 cats), lymphoma (19), mast cell tumor (4), and neuroendocrine carcinoma (2)., Clinical Implications: Obtaining clean margins at surgery seems to increase survival time in cats with malignant colonic neoplasia. Metastasis at the time of surgery decreases survival time. Data from this study indicate that the survival time of certain cats with colonic lymphoma may not be affected by chemotherapy. Cats with an unidentified colonic mass should receive a subtotal colectomy to increase survival time. Cats with colonic adenocarcinoma should receive a subtotal colectomy with consideration of doxorubicin administration to increase survival time.

With the exception of lipoma, neoplasia of the gastrointestinal tract is rare in horses. Lymphosarcoma is the most common neoplasm of the hematopoietic system in horses. In horses with lymphosarcoma of the large colon, clinical signs may include intermittent signs of mild abdominal pain, weight loss, pyrexia, and pelvic flexure impaction caused by impingement of the colonic lumen by the mass. Peritoneal fluid analysis may be normal or have a high total protein concentration. If signs of metastasis are not evident, resection of the large colon affected by the mass may prolong survival.

A subtotal colectomy was performed on 12 normal adult cats using an interrupted apposing suture pattern of monofilament polyglyconate (n = 6) or a biofragmentable intestinal anastomosis ring (Valtrac, Davis and Geck Company, Danbury, CT) (n = 6) composed of polyglycolic acid and barium sulfate. Abdominal radiographs were made daily, beginning 10 days after surgery, to determine fragmentation rates of the anastomosis ring. The cats were euthanatized 30 days after surgery, and a gross and histopathological evaluation of anastomotic healing and stricture formation was performed. The technique for implantation of the anastomosis ring was easy to learn and required only two purse string sutures to complete. Intraoperative complications associated with the anastomosis ring were minor, and included problems with purse string suture placement, small serosal tears, and spasms of the colon that reduced the lumenal diameter. There were no intraoperative complications in the cats with sutured anastomoses. Postoperative recovery was uneventful in all cats. The anastomosis rings fragmented 12.2 +/- 1.1 days (mean +/- standard deviation [SD]) after implantation and passed in the stool 3.8 +/- 1.9 days later without clinical signs in five of six cats. There were no statistically significant differences between the time required to perform the anastomosis (P = .348), postmortem gross anastomosis grades (P = .088), or percent of lumenal stricture (P = .178) between the two groups. Histologically, the only significant differences were an increased muscular inversion in the anastomoses performed using the fragmentable ring (P = .039) and an increased muscular eversion in the sutured anastomoses (P < .001) compared with normal colonic architecture.

Surgical stapling equipment was used to perform an end-to-end colonic anastomosis in 15 cats for the treatment of acquired megacolon. An end-to-end stapling device was passed to the anastomotic site by a trans-cecal approach. Subsequent closure of the cecal incision was accomplished with a thoracoabdominal stapling device. Two cats had hemorrhagic episodes immediately after surgery that required blood transfusions. All 15 cats have had good to excellent health after subtotal colectomy and colocolostomy performed using this stapling technique. Results of this study have demonstrated that "single surgical field" placement of the end-to-end stapling device has the primary advantage of simplicity and a lower chance of contamination compared with (dual field) rectal passage of similar devices. Closure of the cecal access incision is easily performed without reducing the diameter of the large intestinal lumen. The stapling technique provided an efficient and consistent method for anastomosis of the large bowel in cats.

In cats, clinical signs of constipation usually respond to laxatives, fecal softeners, enemas, and dietary management. Uncommonly, constipation is chronic and is associated with a marked increase in the diameter of the colon. When megacolon is present, constipation responds poorly to medical therapy. Without surgical treatment, megacolon may become an intolerable problem, with euthanasia of the cat as the probable outcome. Subtotal colectomy is now established as a satisfactory treatment for idiopathic megacolon in cats. Recently, removal of the colon has been used successfully to treat chronic constipation and megacolon associated with mechanical obstruction of the pelvic canal caused by stenosis from malunion of pelvic fractures. Colectomy has minimal long-term effects on enteric function in cats.

Strangulating volvulus of the large colon was treated by resection and anastomosis of the colon in 9 horses. Tissue specimens were obtained at the site of the resection for histologic evaluation. An attempt was made to correlate the appearance of the colon at the time of surgery to the histologic evaluation and the eventual outcome. Six of the 9 horses (66%) survived. This is in contrast to a reported survival of 34.7 to 36% after decompression and reduction of colonic volvulus. Survival after surgery could not be predicted on the basis of visual assessment or histologic examination.

A leiomyoma of the small colon was discovered incidentally in a 4-year-old Thoroughbred gelding during colic surgery to correct large colon displacement. The mass and 20 cm of small colon were resected, and an end-to-end anastomosis was performed. A postoperative fecal impaction proximal to the anastomosis responded after 5 days to administration of intravenous fluids, analgesics, and stool softeners.

Eleven cats in which subtotal colectomy with end-to-end jejunocolostomy was performed for the treatment of chronic obstipation secondary to pelvic fracture malunion were followed for at least 18 months. Seven cats had no recurrence of clinical signs and no longterm complications. In two cats, constipation was less severe and occurred less frequently; however, medical treatment was still required. In one cat, watery diarrhea gradually changed to semiformed feces of normal consistency by month 6; the cat was clinically normal at month 18. One cat had recurrence of constipation and was euthanatized after 2 years of medical treatment.

A dog with signs of small intestinal disease developed signs of severe large intestinal disease after being treated with multiple agents. Endoscopy and biopsy revealed total destruction of the colonic mucosa, which necessitated total parenteral nutrition plus subtotal colectomy. It was hypothesized that the multiple prior treatments led to an overgrowth of toxigenic or cytotoxic bacteria, which caused this colonic mucosal destruction.

Typhlitis caused by Balantidium coli and requiring surgical resection occurred in three captive lowland gorillas over a 30-month period. Not one of the other gorillas in the colony or their keepers was ill. B. coli is distributed widely geographically and widely among mammals. Asymptomatic commensalism predominates, but invasion of the colonic mucosa can produce diarrhea and dysentery and set the stage for local or systemic spread.

Lactase, maltase, sucrase, and alkaline phosphatase activities were determined in the intestinal mucosa from 3 locations in the small intestine and 4 locations in the large intestine 1 year after extensive large-colon resection (group 1; n = 5) and 1 year after sham operation (group 2; n = 3) in horses. Lactase, maltase, and sucrase activities were similar (P greater than 0.05) between group-1 and group-2 horses in all locations measured in the intestinal tract. Alkaline phosphatase activity in the remaining large colon of group-1 horses was significantly (P less than 0.05) greater than the activity in the large colon of group-2 horses. Decreased apparent digestion of phosphorus and a negative phosphorus balance are persistent features of large-colon resection in horses. Increases in alkaline phosphatase activity in the remaining colon of horses with extensive large-colon resection may be a specific functional adaptive mechanism that attempts to counteract the derangements in phosphorus metabolism.

The enteric function of four cats that had undergone subtotal colectomy for megacolon was compared with that of four normal cats. All cats were fed the same diet before and during the study. History, physical condition, body weight, blood chemistry panel, fasting and postprandial serum bile acids, serum cobalamin concentration, serum folate concentration, fecal weight, fecal water content, fecal fat content, fecal osmolality and electrolyte concentration, quantitative anaerobic fecal bacterial culture, partial thromboplastin time, prothrombin time, breath hydrogen concentration, urinary calcium, phosphorus and electrolyte concentrations, and abdominal radiographic examination with air contrast studies (pneumocolon) were examined. The four cats treated surgically were healthy and thriving and, in general, enteric function was similar to the controls. Bowel movements occurred only slightly more frequently with no significant differences in fecal volume or water content. Serum cobalamin concentrations were significantly higher in cats treated surgically. Fecal sodium concentrations were high and fecal potassium concentrations were low. Results of this study did not show any significant subclinical evidence of abnormal bowel function in cats after subtotal colectomy.

Excessive administration of phenylbutazone was associated with development of right dorsal ulcerative colitis. The clinical signs of right dorsal colitis include chronic colic and weight loss. The laboratory abnormalities include panhypoproteinemia and a high WBC count in the abdominal fluid. Medical management of the chronic colic and protein-losing enteropathy associated with the ulcerative lesions in the right dorsal colon and surgical bypass of the right dorsal colon did not result in long-term resolution of clinical signs. Resection of the ulcerated right dorsal colon through a right lateral approach at the 16th rib resulted in resolution of intestinal protein loss and colic. The results of this case suggest that surgical resection of the ulcerated right dorsal colon may be the recommended treatment for right dorsal ulcerative colitis.

Light microscopy, morphometry and scanning electron microscopy (SEM) were used to examine the mucosal morphology of seven intestinal specimens (three from the small intestine and four from the large intestine) from two horses not subjected to surgery and three horses one year after sham-operation for colon resection. Qualitative and quantitative evaluation revealed similar morphology for all horses except that the unoperated horses had significantly (P < 0.05) fewer goblet cells in the crypts of the large intestine. In the small intestine, SEM demonstrated that villus shape varied and ranged from coned to broad and flat. In the large intestine, SEM of the right ventral and dorsal colon revealed more prominent crypt openings than in the caecum. The small colon contained the most prominent crypt openings with the least variation among horses. In the small intestine, light microscopy and morphometry revealed a greater number of goblet cells and a decreased width to the enterocytes in an aboral direction from the cranial jejunum to the ileum. In the large intestine, the crypt area and crypt depth increased significantly and the intercrypt area decreased significantly in an aboral direction from the caecum to the small colon (P < 0.05). In comparison to the normal morphology, horses one year after extensive large colon resection had significantly greater intercrypt area in the caecum and remaining large colon.

Fecal excretion of a particulate marker, ytterbium (Yb), was evaluated in 9 horses before surgery and 3 weeks, 3 months, and 6 months (4 trials) after sham-operation (group 1; n = 3) or extensive large colon resection (group 2; n = 6). Fecal excretion curves of total Yb excretion, loge Yb excretion, % Yb excretion, loge % Yb excretion, and cumulative % Yb excretion were evaluated, and kinetic analysis was performed on the loge Yb excretion curves to detect mixing pools and to calculate the fractional rate of particulate passage, turnover rate, and pool size. Calculations were performed to determined transit time, mean overall retention time, adjusted mean retention time, peak time, and disappearance time. Values were statistically analyzed to determine differences between groups and among trials (P less than 0.05). Group-2 horses had significantly shorter transit, peak, and mean overall retention times, compared with preoperative values and with values for group-1 horses. Two mixing pools were identified: a slower emptying pool of 5.7% hour-1 (k1) and a faster emptying pool of 12.3% hour-1 (k2). The rate of passage from the first pool (k1) was not altered by colon resection, and was interpreted as being most influenced by the cecum. In further support of this interpretation, the capacity of the k1 pool approximated the capacity of the cecum (17 L). The capacity of the k1 pool significantly expanded by 6 months in the resected horses. the rate of passage from the second pool (k2) significantly increased initially after colon resection (3 weeks and 3 months), but returned to preoperative values by 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Each of 3 digestion trials (3 forage diets) was performed on 2 groups of horses 6 to 12 months after sham operation (group 1; n = 3) or large-colon resection (group 2; n = 5). Diets were alfalfa pellets, alfalfa hay, and grass hay. Feed and fecal analyses were performed to determine apparent digestion of dry matter, organic matter, and crude protein and true digestion of dry matter, organic matter, crude protein, total plant cell wall, hemicellulose, cellulose, and lignin. Additional fecal and metabolic variables determined were percentage of fecal water, total fecal water, metabolic organic matter, metabolic crude protein, and metabolic nitrogen. Large-colon resection decreased the digestion of plant cell wall because of decreased digestion of cellulose in alfalfa pellet and grass hay diets, but not in alfalfa hay diet. Insufficient digestible energy and/or protein from grass hay was obtained by horses with colon resection, and significant (P less than 0.05) weight loss was observed. Voluntary intake was significantly (P less than 0.05) increased by horses with colon resection. Of the diets studied, alfalfa hay was the most appropriate forage diet, compared with average grass hay and alfalfa pellet diet, for horses after extensive large-colon resection. Additionally, horses with colon resection may have higher levels of feed intake than do horses without colon resection.

Large colon resection and anastomosis was performed in 11 horses at various levels of the colon, using several surgical methods. The level of resection ranged from the pelvic flexure to the cecocolic ligament. Nine of 11 horses survived and at follow-up (4 months to 7 years) were free of clinical signs referable to disease of the gastrointestinal tract. Seven horses could be evaluated as to athletic or reproductive function and all returned to original potential.

Ten normal horses had approximately 95% of the length of the large colon resected with a side-to-side anastomosis between right ventral and right dorsal colon performed with surgical stapling equipment. Four horses died shortly after surgery of colitis (1 horse) or failure of the TA 90 transection staple line (3 horses). Another horse died 4 months after surgery from disseminated streptococcal infection but had recovered well from the colon resection. Five horses survived long term (18 months) with no clinical evidence of adverse effects of the resection. Surviving horses had weight loss and soft fecal consistency for 3 to 12 weeks after surgery but returned to preoperative values within 12 months. At a second surgery 1 year later (5 horses) or at necropsy 4 months later (1 horse), fibrous omental adhesions were present over the transection staple line in four horses and over the anastomotic staple line in two horses. Omental adhesions to the everted staple line were moderate but not associated with any clinical sequellae. An incisional hernia was present in one horse. The anastomotic stomata measured between 8 and 9 cm, which was 60% of the size of the original surgically created stomata. Failure of the transection staple line occurred in the first three of five horses in which the procedure was attempted due to improper configuration of the staples or crushing of the tissue between the staples. Experience corrected this complication.

The effect of 60% resection of the large colon vs ischemic insult without resection on the ability of horses to digest grass hay was investigated. Digestion trials were performed on 9 horses before surgery (base line) and 3 weeks, 6 weeks, and 6 months after surgery. The percentage of apparent digestion of crude protein, crude fiber, nitrogen-free extract, calcium, phosphorus, magnesium, manganese, copper, and zinc was calculated. Horses that had resection (n = 5) had decreased apparent digestion of crude protein, crude fiber, and phosphorus 3 weeks after surgery, compared with those in horses with ischemic insults (n = 4) and with base-line values. Horses with ischemic insults also had a decrease in crude protein digestion 3 weeks after surgery, compared with base-line values. All horses returned to base-line values of digestion at the 6-month trials, although horses that had resection had higher fecal concentrations of phosphorus and nitrogen-free extract than did horses with ischemic insult. During the study, all horses had maintained good body condition.

Nutritional alterations were evaluated in 9 horses before surgery and 3 weeks, 3 months, and 6 months (4 total trials) after sham operation (group 1; n = 3) or extensive large colon resection (group 2; n = 6). Feed and fecal analyses were performed to determine apparent digestion of dry matter, organic matter, crude protein, calcium, phosphorus, magnesium, potassium, manganese, zinc, copper, and iron, and true digestion of dry matter, organic matter, crude protein, total plant cell wall, hemicellulose, cellulose, and lignin. Additional fecal and metabolic variables included the percentage of fecal water (water in the feces), total fecal water, metabolic organic matter, metabolic crude protein, and metabolic nitrogen. A CBC and standard series of biochemical tests were performed. Large colon resection decreased (P less than 0.05) the true digestion of dietary crude protein and cellulose and apparent digestion of phosphorus, and it increased the fecal metabolic matter and water loss. Total fecal output increased 45% and total fecal water increased 55%. Phosphorus digestion was decreased (P less than 0.05) in group-2 horses, but effects of this were not detected on analysis of blood variables or on physical examination. Nevertheless, after extensive large colon resection, horses can regain body weight lost after surgery and have no overt physical changes when fed an alfalfa pellet diet that meets greater-than-maintenance requirements. Ad libitum water access is suggested, because these horses may have to consume 2 gal/day more than would normal horses.

Total colectomy with end-to-end ileorectal anastomosis was performed in eight healthy adult cats. Hydration status, body weight, attitude, appetite, and stool consistency were monitored for 24 weeks. Ileal water absorption was determined at weeks 1, 6, 12, 18, and 24 using the double-lumen catheter intestinal perfusion technique with polyethylene glycol as the indicator substance. Bowel adaptation was evaluated by histologic morphometric analysis of full-thickness ileal biopsies taken at the time of total colectomy and at weeks 6, 12, 18, and 24. The anastomoses were examined at necropsy for evidence of leakage and development of strictures. All cats resumed normal activity in 48 hours and maintained or gained weight during the study. Small volumes of watery diarrhea were present immediately after surgery, but by week 1 all cats had a semi-solid nonformed stool. At month 2, three cats developed semi-solid formed stools. One cat had occasional perineal soiling and five cats had at least one episode of hematochezia. There was improvement in ileal water absorption in two cats, and there were significant increases in villus height, enterocyte height, and enterocyte density in all cats. Results of postmortem examination of the anastomosis showed no evidence of stricture in any cat.

Chronic constipation, nonresponsive to medical management and associated with idiopathic megacolon, was diagnosed in 38 cats from 1979 to 1985. All cats were treated by subtotal colectomy and enterocolostomy, in which the ileum or distal portion of the jejunum was joined to a 2- to 4-cm segment of distal portion of the colon preserved to accommodate an end-to-end anastomosis. After surgery, cats usually were depressed and anorectic, had tenesmus, and passed liquid tarry feces. In 37 cats 1 week to 3 months after surgery, character of the feces changed from diarrhea to soft semiformed or formed feces. One cat had severe diarrhea that was nonresponsive to diet change and pharmacologic treatment; the diarrhea resolved after 4.5 months. One cat developed a stricture of the enterocolostomy, which was relieved by 3 balloon catheter dilatations. All cats regained normal appetite, did not lose weight, and were not incontinent. Three cats had sporadic episodes of constipation and were easily treated. Results of histologic examination of the resected portion of colon in 23 cats were inconclusive.

With large colon resection and anastomosis, up to 95 per cent of the length of the large colon has been successfully removed. A hand-sewn end-to-end anastomosis is effective for lesions in the left dorsal colon and pelvic flexure. Transection and a side-to-side anastomosis with stapling equipment is most effective for extensive resections (greater than 50 per cent). Horses with extensive colon resection (95 per cent) have permanent deficiencies of water absorption and digestion of cellulose and protein. Fermentative capacity is reduced, owing to decreased particulate matter retention time in the smaller capacity colon. These deficits are minimized with alfalfa hay as the source of forage (fed at 2 per cent of the body weight), and normal blood variables and body weight can be maintained. Voluntary intake increases to help maintain a positive nutrient balance. Grass hay, owing to the higher cell wall content, is inadequate as the sole source of energy and protein, and weight loss will occur. Ad libitum intake of water is recommended at all times, owing to the increased fecal water loss.

The case records of 4 cats and 1 dog with megacolon and constipation were reviewed to study the history, clinical signs, pathologic changes, and longterm results of surgical treatment. The 4 cats had idiopathic megacolon. The dog had megacolon secondary to dietary indiscretion. All animals had radiographic evidence of a large colon, which was confirmed by exploratory coeliotomy. Two of the cats and the dog had an intraoperative finding of megacecum as well. Subtotal colectomy was performed in all cases, with the ileocolic valve being removed in 3 of these cases. End-to-side anastomosis was used to restore the integrity of the bowel. All animals were treated successfully with this surgical technique, as judged by clinical response and owner satisfaction. Histologically, there were no consistent lesions to explain the cause of this disease in the cats.