Performance and ruminal fermentation of dairy cows fed whole cottonseed with elevated concentrations of free fatty acids in the oil.

Twenty-four lactating Holstein cows were used in an 8-wk completely randomized design trial to examine the effects of feeding whole cottonseed (WCS) with elevated concentrations of free fatty acids (FFA) in the oil on intake and performance. Treatments included WCS with normal concentrations of FFA (6.8%, control) and 2 sources of WCS with elevated FFA [HFFA1 (24.1%) or HFFA2 (22.3%)]. The 2 sources of WCS with elevated FFA differed in that HFFA2 were discolored from being initially stored with excess moisture, which led to heating and deterioration during storage, whereas HFFA1 were normal in appearance and the increase in FFA occurred without heating and visible damage to the WCS. Nutrient concentrations were similar among WCS treatments, which provided 14% of the total dietary dry matter. Dry matter intake tended to be higher for cows fed HFFA2 compared with control and HFFA1. Yield of milk and components was similar among treatments, but milk fat percentage was lower for HFFA1 and HFFA2 compared with control. In a concurrent 3 x 3 Latin square trial with 6 ruminally cannulated Holstein cows, molar proportions of isobutyrate were higher for HFFA2 than control and HFFA1, but no differences were observed in acetate or propionate. Results of these trials indicate that feeding WCS with high concentrations of FFA decreases milk fat percentage but does not alter dry matter intake, milk yield, or concentrations of other components. The minor changes in ruminal fermentation that were observed do not account for the decrease in milk fat percentage.

Quantitative assessment of the equine hoof using digital radiography and magnetic resonance imaging.

REASONS FOR PERFORMING STUDY: Evaluation of laminitis cases relies on radiographic measurements of the equine foot. Reference values have not been established for all layers of the foot. OBJECTIVES: To establish normal hoof wall and sole measurements using digital radiography (DR) and magnetic resonance imaging (MRI) and to document tissue components present in the dorsal hoof wall and solar layers seen on DR. STUDY DESIGN: Prospective observational case-control study. METHODS: Digital radiography and MRI were performed on 50 cadaver front feet from 25 horses subjected to euthanasia for nonlameness-related reasons. Four observers measured hoof wall (dorsal, lateral and medial) and sole thickness (sagittal, lateral and medial) using DR and magnetic resonance images. One observer repeated the measurements 3 times. Inter- and intraobserver correlation was assessed. RESULTS: Digital radiography and MRI measurements for the normal hoof wall and sole were established. Inter- and intraobserver pairwise Pearson's correlation for DR (r>0.98) and MRI measurements (r>0.99) was excellent. Based on MRI, the less radiopaque layer on DR is comprised of the stratum lamellatum and stratum reticulare. CONCLUSIONS: Normal DR and MRI measurements for the hoof wall and sole were established. On DR images, the less radiopaque layer of the foot observed corresponds to the critical tissues injured in laminitis, the strata lamellatum and reticulare. These reference measurements may be used by the clinician to detect soft-tissue changes in the laminitic equine foot and provide a foundation for future research determining changes in these measurements in horses with laminitis.

Treatment of guttural pouch mycosis.

Seventeen cases of guttural pouch mycosis (including two bilaterally affected cases) were diagnosed in a three year period. The presenting signs were, in order of frequency, epistaxis at rest, nasal catarrh, pharyngeal paralysis, ipsilateral laryngeal hemiplegia, swelling of the submandibular/parotid region, extension of the head and neck and dyspnoea. Ligation of the origin of the internal carotid and occipital arteries was attempted in 10 of the cases exhibiting epistaxis. Bilateral ligation was performed on one animal with an untoward sequelae. Where surgery was successfully completed further haemorrhage was prevented in eight out of nine affected pouches (89 per cent). Medical treatment involving local administration of various antifungal preparations via a specially designed catheter and/or the oral administration of benzimidazole drugs was successful in eliminating the mycotic plaque in most cases. Cases which presented with pharyngeal paralysis were all fatal.

Monorchidism in the horse.

Six horses with monorchidism, identified at surgery for cryptorchidectomy, are reported. All six presented with a single scrotal testis. Following surgical removal of one testis, they were either hormonally, anatomically or behaviourally determined to be geldings. Three other horses reported in the literature are reviewed. Of these nine cases of monorchidism, eight were thought to be caused by testicular degeneration and one by testicular agenesis. The vaginal process was present in all of the former and absent in the latter. The left side was involved in five of these eight horses. In seven, the epididymis was absent and, in the remaining two, only the epididymal tail was present. The condition was thought to be congenital in the six horses in this series. A surgical approach to identify accurately monorchid horses is described.

Effects of Aspergillus oryzae fermentation extract on in vitro equine cecal fermentation.

The objective of this study was to examine the effects of Aspergillus oryzae fermentation extract on the in vitro equine cecal fermentation of soluble starch, amino acids/peptides, coastal bermudagrass hay, and alfalfa hay. Cecal contents were obtained from a cecally fistulated Quarter Horse gelding fed coastal bermudagrass and grain (70:30) either unadapted or adapted to dietary A. oryzae supplementation (2 g/d). Mixed cecal microorganisms were incubated in anaerobic media for either 24 h (soluble starch, amino acids) or 48 h (bermudagrass hay, alfalfa hay). A. oryzae was added to the incubation bottles (n = 4) at concentrations of 0, .07, or .7 g/L. Fermentation of soluble starch in the presence of .7 g/L of A. oryzae resulted in increased concentrations of acetate, propionate, NH3, and L-lactate and decreased final pH. Addition of .7 g/L of A. oryzae to amino acid/peptide fermentations decreased final pH and increased concentrations of H2, acetate, propionate, butyrate, and total VFA. When alfalfa hay or bermudagrass hay was fermented with .7 g/L of A. oryzae, CH4, IVDMD, and digestion of NDF and ADF decreased. When adapted mixed cecal microorganisms were used, .7 g/L of A. oryzae did not inhibit methanogenesis or fiber digestion and L-lactate concentrations were not increased with soluble starch as the substrate. These results suggest that cecal microorganisms exposed to A. oryzae via the diet may adapt to the product. Incorporation of A. oryzae into in vitro incubations at concentrations similar to current recommended usage levels resulted in little change in final pH and fermentation products.

Effects of forage and sunflower oil levels on ruminal biohydrogenation of fatty acids and conjugated linoleic acid formation in beef steers fed finishing diets.

Six Hereford steers (295 kg) cannulated in the proximal duodenum were used to evaluate the effects of forage and sunflower oil level on ruminal biohydrogenation (BH) and conjugated linoleic acid (CLA) outflow. Steers were fed one of six treatment diets in a 3 x 2 factorial arrangement of treatments (grass hay level: 12, 24, or 36% of DM; and sunflower oil level: 2 or 4% of DM) in a 6 x 6 Latin square design. The remainder of the diet was made up of steam rolled corn and protein/mineral supplement. Duodenal samples were collected for 4 d following 10-d diet adaptation periods. Data were analyzed with animal, period, forage level, sunflower oil level, and two-way interaction between forage and sunflower oil level in the model. Dry matter intake showed a quadratic response (P < 0.04), with an increase in DMI as forage level increased from 12 to 24% followed by a decrease in DMI when 36% forage was fed. Flow of fatty acids at the duodenum was higher (P < 0.03) for 4 vs. 2% sunflower oil diets, and similar among forage levels. Apparent ruminal digestibility of NDF increased in a linear manner (P < 0.04) as dietary forage level increased. Ruminal BH of dietary unsaturated 18-C fatty acids, oleic acid, and linoleic acid increased linearly (P < 0.05) as dietary forage level increased. Linoleic acid BH tended (P < 0.07) to be greater for 4 than 2% sunflower oil level. Duodenal flow of pentadecyclic, stearic, linolenic, and arachidic acids increased linearly (P < 0.05) as dietary forage level increased from 12 to 36%. Duodenal flow of linoleic acid decreased in a linear manner (P < 0.03) with increasing dietary forage level. Flow of trans-10 octadecenoate decreased linearly (P < 0.03) as dietary forage level increased, whereas trans-11 vaccenic acid flow to the duodenum increased (P < 0.01) linearly with increased dietary forage. Dietary forage or sunflower oil levels did not alter the outflow of cis-9, trans-11 CLA. Flows of cis-11, trans-13, and cis-9, cis-11 CLA increased linearly (P < 0.05) with increased dietary forage. Flows of cis-11, cis-13, and trans-11, trans-13 CLA decreased linearly (P < 0.05) with increased dietary forage. Increasing dietary forage levels from 12 to 36% in beef cattle finishing diets increased BH of unsaturated 18-C fatty acid and outflow of trans-11 vaccenic acid to duodenum without altering cis-9, trans-11 CLA outflow.

Comparison of Tifton 85 and Coastal bermudagrasses for yield, nutrient traits, intake, and digestion by growing beef steers.

A study was undertaken to compare Tifton 85 (T85) and Coastal (CBG) bermudagrasses for effects of cultivar and age at harvest on yields of DM and digestible DM, in vitro digestion, nutrient content, cell wall composition, in situ digestion kinetics, and feed intake and digestion by growing beef steers. In Exp. 1, T85 and CBG forages staged for growth in May or July of 1993 were harvested at 3, 4, 5, 6, 7, and 8 wk from subplots. Tifton 85 bermudagrass had 7.1% greater DM yield, 18.2% higher (P < .05) digestible DM yield, and 7.1% greater IVDMD than CBG, and, after 5 wk of forage growth, IVDMD of both T85 and CBG decreased with increased age at harvest (P < .05). In Exp. 2, T85 and CBG forages staged for growth in July 1997 were harvested at 2, 3, 4, 5, 6, and 7 wk from subplots. Even though T85 had higher concentrations of NDF and ADF than CBG, T85 had 34.1% higher DM yield, 47.9% higher digestible DM, 55.0% higher digestible NDF, 91.7% higher digestible ADF, greater IVDMD, in vitro NDF and ADF disappearances, and higher in situ DM and NDF digestion (P < .05). Coastal bermudagrass had higher concentrations of lignin and lower concentrations of total neutral sugars, arabinose, glucose, and xylose than T85 (P < .05). In vitro digestibilities of DM, NDF, and ADF were lower and concentrations of ADF and lignin were greater for 7- vs 6-wk harvests of both T85 and CBG (P < .05). In Exp. 3, T85 and CBG forages staged for growth in July 1997 were harvested as hay at 3, 5, and 7 wk from .8-ha pastures and fed to 36 individually penned growing beef steers (initial BW = 244 kg) to quantify ad libitum intake without supplementation. Tifton 85 bermudagrass had lower concentrations of lignin and ether-linked ferulic acid and greater concentrations of NDF, ADF, hemicellulose, and cellulose than CBG (P < .05). Steers fed T85 had higher (P < .05) digestion of DM, OM, NDF, ADF, hemicellulose, and cellulose than steers fed CBG. Digestion of NDF, ADF, hemicellulose, and cellulose decreased (P < .05) with increased age at harvest for both cultivars. In conclusion, T85 produced more DM and had more digestible nutrients in vitro, in situ, and in vivo than CBG, and 3 and 5 wk of growth would be recommended ages to harvest either cultivar.

Use of nonergot alkaloid-producing endophytes for alleviating tall fescue toxicosis in stocker cattle.

Grazing studies were conducted to determine cattle growth performance, evaluate toxicosis, and compare grazing behavior in stocker cattle grazing nonergot alkaloid-producing endophyte-infected (AR542 or AR502), endophyte-free (E-), or wild-type toxic endophyte-infected (E+) Jesup, Georgia-5, and Kentucky-31 tall fescue. Replicated 0.81-ha tall fescue paddocks were established at the Central Georgia Branch Station at Eatonton and the Northwest Georgia Branch Station at Calhoun during October 1998 and were stocked with beef cattle for autumn and spring periods from fall 1999 through spring 2002. Mean ergot alkaloid concentrations were higher (P < 0.01) on E+ pastures than the other treatments at both locations. At Calhoun and Eatonton, post-treatment serum prolactin concentrations were decreased (P < 0.01) on E+ compared with AR542, AR502, and E- tall fescue. Cattle on AR542, AR502, and E- pastures had lower (P < 0.05) post-treatment rectal temperatures than cattle grazing E+ tall fescue during spring at Eatonton and Calhoun. Calf ADG was higher (P < 0.05) on AR542, AR502, and E- as compared with E+ tall fescue during autumn and spring grazing at Eatonton, and at Calhoun, cattle on E+ pastures had lower (P < 0.05) ADG in both autumn and spring. Gain/hectare was higher (P < 0.05) on AR542, AR502, and E- than on E+ during autumn at Eatonton and during spring at both locations. In autumn at Calhoun, gain/hectare was greater (P < 0.05) on AR502 and E- compared with E+ tall fescue. During April, May, and June, cattle grazing E+ pastures at Eatonton spent more (P < 0.01) time idling, more (P < 0.01) time standing, and used more (P < 0.01) water than cattle on AR542 and E- tall fescue. Daily prehensions and biting rate were each higher (P < 0.01) on AR542 and E- tall fescue than E+ tall fescue in both grazing seasons. There were no differences among pasture treatments for bite size in either spring (P = 0.50) or autumn (P = 0.34). Steers grazing E+ pastures had lower DMI than steers grazing AR542 and E- pastures during spring (P < 0.10) and lower DMI than steers grazing E- pastures during autumn (P < 0.05). Daily steer water usage was decreased (P < 0.10) in E+ pastures compared with AR542 and E- pastures during late fall. These results indicate that nonergot alkaloid-producing endophyte technology is a promising option for alleviating tall fescue toxicosis in stocker cattle.

Effects of exploratory laparotomy on plasma and peritoneal coagulation/fibrinolysis in horses.

Plasma and peritoneal fluid samples were collected before and after surgery from 6 horses undergoing a ventral midline exploratory laparotomy and from 6 anesthetized control horses. Coagulation/fibrinolytic components measured in the plasma and peritoneal fluid of these horses included the functional activity of antithrombin III, alpha-2 antiplasmin, plasminogen, and protein C, and the concentrations of fibrinogen and fibrin degradation products. Peritoneal fluid antithrombin III, fibrin degradation products, and plasminogen values were significantly increased after surgery (over time) in principal horses. Compared with control horses, postoperative peritoneal fluid from horses undergoing laparotomy had significantly increased antithrombin-III activity at 12 and 72 hours, alpha-2 antiplasmin activity at 24 hours, fibrin degradation product concentrations at 6, 12, 24, 72, 96, and 144 hours, plasminogen activity at 6, 12, 24, 48, 72 and 96 hours, and protein-C activity at 12, 24, 72, and 96 hours. There were no significant changes in the peritoneal fibrinogen concentration in principal horses. Plasma plasminogen activity was significantly decreased at 24 hours after surgery in principal horses, compared with controls. Changes were minimal in the remaining plasma coagulation/fibrinolytic components of horses undergoing laparotomy. Plasma and peritoneal fluid values of anesthetized control horses did not change.

Effects of ischemia and dimethyl sulfoxide on equine jejunal vascular resistance, oxygen consumption, intraluminal pressure, and potassium loss.

Physiologic effects of 1 hour of ischemia and 1 hour of reperfusion on equine jejunum and protective effects of systemic administration of dimethyl sulfoxide (DMSO, 1 g/kg of body weight) were investigated in 18 ponies, using neurally intact segments of jejunum perfused at constant flow with heparinized blood. Ponies were allotted to 4 groups: group 1, saline solution administered (control, n = 3); group 2, DMSO administered (DMSO, n = 3); group 3, ischemia induced and saline solution administered (ischemia, n = 6); and group 4, ischemia induced and DMSO administered (ischemia-DMSO, n = 6). Intestinal vascular resistance (R, mm of Hg/ml/min/100 g), oxygen consumption (VO2, ml/min/100 g), frequency and amplitude of rhythmic changes in intraluminal pressure, intestinal compliance (C, ml/mm of Hg), and arteriovenous potassium concentration difference (delta AV [K+], mEq/L) were determined and compared with stable preischemic values within groups. There were no significant changes in any variable in ponies of groups 1 or 2. In ponies of group 3, significant (P less than or equal to 0.05) changes included: an initial increase in R during reperfusion, followed by a decrease to values below preischemic values by 15 minutes of reperfusion; decreased VO2 during the entire reperfusion period; increased amplitude of rhythmic contractions during initial reperfusion; decreased frequency of rhythmic contractions during ischemia; and increased delta AV [K+] during initial reperfusion. Changes in ponies of group 4 were identical to changes in ponies of group 3, with the exception that DMSO administration prevented the decrease in R during reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphologic and ultrastructural evaluation of effect of ischemia and dimethyl sulfoxide on equine jejunum.

Morphologic changes in equine jejunal segments subjected to 1 hour of ischemia and 1 hour of reperfusion, and protective effects of systemic administration of dimethyl sulfoxide (DMSO; 1 g/kg of body weight) were investigated in 18 ponies, using light microscopy and scanning and transmission electron microscopy. Ponies were allotted to 4 groups: group 1--control (n = 3); group 2--DMSO (n = 3); group 3--ischemia (n = 6); and group 4--ischemia and DMSO (n = 6). In each pony, 2 jejunal sections were evaluated. The first section was obtained prior to induction of ischemia, and the second was obtained 2 hours later after reperfusion. Mucosal lesions were graded from 0 (normal) to 5 (most severe). Combined ischemia and reperfusion of 2 hours' duration induced moderately severe mucosal injury to the equine jejunum (group 3; grade 1.5 to 2.5), characterized principally by disruption of enterocyte attachment from the basement membrane and lamina propria. Fluid accumulation disrupted enterocyte cell-to-cell adhesion toward cell bases, while apical tight junctions and desmosomal junctions toward the luminal surface remained intact. Intracytoplasmic organellar changes within enterocytes were not a prominent feature of the injury. The aforementioned processes were marked at the villus tip and progressed down the villus sides. These findings support the importance of mechanisms leading to early subepithelial fluid accumulation rather than that of direct severe enterocyte injury. Further, fluid accumulation does not appear to arise from intercellular migration from the luminal surface. In this model, a pathomechanical effect caused by vigorous villus retraction appears to exacerbate epithelial lifting toward the villus tip.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of distention and neostigmine on jejunal vascular resistance, oxygen uptake, and intraluminal pressure changes in ponies.

The influence of distention (high baseline intraluminal pressure) and neostigmine methylsulfate on intestinal vascular resistance, oxygen uptake, and intraluminal pressure changes (rhythmic contractions) was studied in terminal jejunal segments, which were perfused at a constant rate, in 16 anesthetized ponies. When baseline intraluminal pressure was increased to 10 mm of Hg, the intestinal vascular resistance and amplitude of rhythmic contractions were increased. Neostigmine induced cyclic increases in amplitude of rhythmic contractions whether intraluminal pressure was 0 or 10 mm of Hg. Neostigmine also increased intestinal oxygen uptake at intraluminal pressures of 0 mm of Hg, but not at 10 mm of Hg, and vascular resistance was not altered at either intraluminal pressure. The results indicate that intestinal hemodynamics are adversely affected by distention. Further, neostigmine did not adversely affect intestinal hemodynamics while increasing rhythmic contractions, suggesting that neostigmine may be useful in the treatment of ileus in equids.

Palmar digital vessel relaxation in healthy horses and in horses given carbohydrate.

OBJECTIVE: To compare in vitro smooth muscle relaxation of palmar digital vessels from healthy horses with those from horses in the prodromal stage of experimentally (carbohydrate) induced laminitis. ANIMALS: 16 adult horses. PROCEDURE: Segments of palmar digital vessels were obtained from 5 healthy horses and 6 horses given carbohydrate. Vascular rings from the palmar digital artery and vein were suspended in individual organ baths containing buffer solution and indomethacin; isometric tension was recorded, and contraction and relaxation were compared. Smooth muscle contraction in response to cumulative addition of phenylephrine was recorded in the absence and presence of 1 microM NG-nitro-L-arginine methyl ester (L -NAME). After wash out, vascular rings were preconstricted with phenylephrine (0.3 microM), and cumulative endothelium-dependent (acetylcholine-induced) and independent (nitroprusside-induced) smooth muscle relaxations were recorded in the absence or presence of L -NAME. RESULTS: Phenylephrine increased vascular smooth muscle tone in ring preparations of palmar digital arteries and veins. Addition of acetylcholine or nitroprusside induced relaxation of palmar digital artery and vein ring preparations. Use of L-NAME (1 microM) significantly reduced maximal relaxation induced by acetylcholine, but not by nitroprusside. Maximal relaxation induced by acetylcholine, but not by nitroprusside, was reduced in vascular rings prepared from carbohydrate-overloaded horses. CONCLUSION AND CLINICAL RELEVANCE: Reduced endothelium-dependent relaxation of palmar digital vessels may have a role in the pathophysiology of acute laminitis after carbohydrate overload in horses.

Effects of flunixin meglumine on jejunal blood flow, motility, and oxygen consumption in ponies.

Using isolated autoperfused intestinal segments, the effects of flunixin meglumine administration on systemic arterial blood pressure, jejunal blood flow, vascular resistance, motility, arteriovenous oxygen difference, and oxygen consumption were determined in 10 anesthetized ponies ventilated with a mixture of halothane and oxygen. Saline solution or flunixin meglumine (1.1 mg/kg of body weight) was infused as a single bolus into the left jugular vein. By 10 minutes, flunixin meglumine increased systemic arterial blood pressure and increased intestinal vascular resistance. The jejunal blood flow, however, was not significantly decreased until 1 hour after flunixin meglumine administration. Intestinal motility, arteriovenous oxygen difference, and oxygen consumption were unchanged. Results indicated that acute administration of flunixin meglumine increases systemic arterial pressure and intestinal vascular resistance, but the resulting intestinal vasoconstriction does not lead to compromise of intestinal viability.

Comparison of surgical and nonsurgical treatment of humeral fractures in horses: 22 cases (1980-1989).

Medical records of 22 horses with humeral fractures were reviewed. The horses were from 2 to 144 months old (mean, 25.8 +/- 37.3 months). Ten horses were treated with stall confinement, 3 were treated surgically, and 9 were euthanatized at the time of diagnosis. Seven of 10 horses treated nonsurgically (stall confinement) were able to be ridden 5 to 12 months after the diagnosis was made (mean, 7.5 +/- 2.6 months). One horse treated nonsurgically was euthanatized 6 months after diagnosis because of laminitis in the contralateral limb. Two horses treated nonsurgically were lost to follow-up evaluation. Two of the 3 horses treated surgically had fractures repaired with Rush pins. The fractured humerus of the third horse was repaired with lag screws. Of the 3 surgically treated horses, 1 was pasture sound 10 months after surgery, but developed varus deviation in the contralateral carpus 6 weeks after repair; 1 horse was euthanatized 2 weeks after surgery because of failure of the implant; and the other horse was sound for riding 10 months after surgery. On the basis of these findings, young horses with humeral fractures that are treated nonsurgically can become sound for riding.

Incarceration of the small colon through a rent in the gastrosplenic ligament in a pony.

A 10-year-old castrated male pony was examined for intermittent signs of abdominal pain of 3 days' duration. An incarceration of the small colon through a rent in the gastrosplenic ligament was found. Resection and end-to-end anastomosis were performed on the affected portion of the small colon. The pony recovered and returned to its previous degree of activity. Incarceration of the small intestine and large colon through rents in the gastrosplenic ligament are documented, although involvement of the small intestine is more common. To the best of our knowledge, incarceration of the small colon has not been reported. Although a rare event, incarceration of the small colon in the gastrosplenic ligament should be considered in the differential diagnosis list for horses with intermittent signs of abdominal pain.

Severe nasal hemorrhage in an anesthetized horse.

An 8-year-old Thoroughbred gelding with colic was anesthetized for surgical correction of right dorsal displacement of the ascending colon. Removal of the nasogastric tube at the end of surgery resulted in hemorrhage from the nares and loss of 24 L of blood. Treatment included administration of acetated Ringer's solution, hypertonic saline solution, and dobutamine. A blood transfusion was started after hemorrhage was controlled, and arterial pressure was restored to the prehemorrhage value, but was stopped after infusion of 2.7 L of blood because of a suspected adverse reaction. This case indicates that infusion of balanced electrolyte solution, hypertonic saline solution, and dobutamine may maintain adequate arterial pressure after severe blood loss, and also supports the suggestion that administration of hypertonic saline solution potentiates blood loss in the absence of hemostasis.

Comparison of medical and surgical treatment for impaction of the small colon in horses: 84 cases (1986-1996).

OBJECTIVE: To characterize clinical findings and compare effects of treatment and outcome for horses treated medically or surgically for impaction of the small colon. DESIGN: Retrospective study. ANIMALS: 84 horses with impaction of the small colon. PROCEDURE: Medical records were reviewed for history, physical examination findings, laboratory values, treatment, response to treatment, complications, out-come, and necropsy findings. RESULTS: 47 horses were treated medically and 37 horses were treated surgically. Significant differences between groups were not identified for duration of clinical signs, physical examination findings, or laboratory values. Horses treated surgically were hospitalized longer than horses treated medically. Complications recorded during hospitalization included diarrhea, jugular thrombophlebitis, recurrent colic, fever, and laminitis. Salmonella organisms were isolated from 20 horses. Horses treated surgically were more likely to have signs of moderate abdominal pain, gross abdominal distention, and positive results for culture of Salmonella spp than horses treated medically. Follow-up information was available for 27 horses treated medically and 23 horses treated surgically. Twenty-four (72%) and 21 (75%) of the horses, respectively, survived and were being used for their intended purpose at least 1 year after treatment. CLINICAL IMPLICATIONS: Colitis may be a predisposing factor for impaction of the small colon in horses. Prognosis for horses treated surgically or medically is fair.

Lameness in a mare with signs of arteriovenous fistula.

A 5-year-old mare was evaluated for lameness and swelling of the right forelimb. Clinical findings, including peripheral edema, venous pulsation, palpable thrill in the cephalic vein, disparate arteriovenous oxygen tension differences between the left and right forelimbs, and Branham sign, were suggestive of arteriovenous fistula. Failure to identify the fistula by angiography was attributed to closure of the shunt during anesthesia. Surgical exploration of the affected limb to identify the shunt also was unsuccessful.

Use of a multifenestrated indwelling lavage system for treatment of septic digital tenosynovitis in cattle.

Septic tenosynovitis was diagnosed in seven cattle on the basis of history, physical examination, radiographs, cytological examination of tendon sheath fluids, and microbial culture. A commercially available indwelling multifenestrated silicone rubber drain was used to perform frequent lavage of the flexor tendon sheaths. The sepsis resolved in all cattle. Five of six cattle for which long-term (> 1 year) follow-up information was available were clinically sound on the affected limb and had remained productive members of the herd.