The digestive tract in horses is a complex system responsible for the breakdown and absorption of nutrients essential for maintaining equine health. It includes several key components: the mouth, esophagus, stomach, small intestine, cecum, large colon, small colon, and rectum. Each segment of the digestive tract performs specific functions, from the mechanical breakdown of feed to the enzymatic digestion and absorption of nutrients. The horse's digestive system is uniquely adapted to process fibrous plant material, relying heavily on microbial fermentation, particularly in the hindgut. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and function of the equine digestive tract, as well as common disorders and their management.
Leandro RM, Filho RPPF, De Silvio MM, Quilici AP, Sattin MM, Paretsis BF, Souza VA.Anatomy is traditionally regarded as a difficult, non-motivating course involving a large body of theoretical and practical content, and it is often associated with high levels of dropout and failure. Given the relevance of the topic, we propose an alternative active multisensory teaching tool consisting of the construction of a low-fidelity anatomical model assembled into an articulated equine skeleton. Model construction and assembly assists students in the recognition of the topography and anatomical boundaries of the equine abdominal digestive system. Digestive system organs (liver, pancre...
Crotch-Harvey L, Thomas LA, Worgan HJ, Douglas JL, Gilby DE, McEwan NR.Anthelmintics are used as anti-worming agents. Although known to affect their target organisms, nothing has been published regarding their effect on other digestive tract organisms or on metabolites produced by them. The current work investigated effects of fenbendazole, a benzimidazole anthelmintic, on bacteria and ciliates in the equine digestive tract and on and their major metabolites. Animals receiving anthelmintic treatment had high faecal egg counts relative to controls. Analysis was performed over two weeks, with temporal differences detected in bacterial populations but with no other ...
Gerstner K, Liesegang A.Free faecal water (fluid excreted separate from normal faeces) is a common problem of unknown origin in horses. Multifactorial causes are assumed. This study assessed the effect of a commercial product (EMP) sold to help support intestinal health of horses, particularly regarding the occurrence of free faecal water. The hypothesis was that water-binding capacity and microbial activity are improved in the large intestine of horses fed EMP. EMP contained montmorillonite-bentonite, whey and extracts from hop and absinthium. Eight adult and healthy horses kept on the same diet and bedding were add...
Nakamae Y, Ishihara A, Itoh M, Yanagawa M, Sasaki N, Yamada K.Computed tomography (CT) was performed for an 18-year-old female pony with enterolithiasis in the prone and supine positions. CT images from the prone position revealed displacement of the large dorsal colon, which contained an enterolith to the ventral side of the abdomen, and those from the supine position revealed displacement to the dorsal side. A high-density material suggestive of a metallic foreign body was also observed in the enterolith core. An enterolith (422 g, 104 mm) was surgically removed from the large dorsal colon. This caused no complications after surgery and increased the h...
Williams TL, Mochal-King C, Rude BJ, Weed BC, Nicodemus MC.Cecal and ileal cannulations have previously been used to determine equine digestibility and define gastrointestinal physiology. However, research has been limited to specific portions of the equine digestive tract lacking utilization of dual cannulations. The purpose of this study was to develop and implement surgical and preoperative and postoperative procedures for cannulation of dual sections, ileum and cecum, of the equine digestive tract including development of recommendations for addressing postsurgery complications. A total of 8 ponies went through surgical procedures for the placemen...
Stegelmeier BL, Davis TZ.Because most poisonings occur by toxin ingestion, the gastrointestinal system is the first exposed and, in most cases, it is exposed to the highest toxin concentrations. Consequently, enterocyte damage is common. However, because many toxins produce organ-specific damage, and enterocyte necrosis is easily confused with autolysis, many gastrointestinal lesions are overlooked or overshadowed by other clinical and pathologic changes. The objective of this work is to review several common toxins and poisonous plants that produce primarily gastrointestinal disease.
Montgomery JB, Bracamonte JL, Alam MW, Khan AH, Mohammed SK, Wahid KA.This pilot study assessed wireless capsule endoscopy in horses. Image transmission was achieved with good image quality. Time to exit the stomach was variable and identified as one limitation, together with gaps in image transmission, capsule tumbling, and inability to accurately locate the capsule. Findings demonstrate usefulness and current limitations. Cette étude pilote a évalué l’endoscopie par capsule chez les chevaux. La transmission d’images a permis d’obtenir une bonne qualité d’image. Le temps jusqu’à la sortie de l’estomac était variable et identifié comme une li...
Hummel J, Scheurich F, Ortmann S, Crompton LA, Gerken M, Clauss M.There is a discrepancy in the literature on potential digesta separation mechanisms in horses, with both a selective retention of fine and of large particles postulated in different publications. To assess the net effect of such mechanisms, we fed ponies on a hay-only diet a pulse dose of whole (unchopped) marked hay together with a solute marker, collected faeces on a regular basis, measured marker concentrations in whole faeces and in their large (2.0-16 mm), medium (0.5-1.0 mm) and small (0.063-0.25 mm) particle fraction, and calculated the corresponding mean retention times (MRTs). For ...
Harlow BE, Lawrence LM, Harris PA, Aiken GE, Flythe MD.Cereal grains are often included in equine diets. When starch intake exceeds foregut digestion starch will reach the hindgut, impacting microbial ecology. Probiotics (e.g., lactobacilli) are reported to mitigate GI dysbioses in other species. This study was conducted to determine the effect of exogenous lactobacilli on pH and the growth of amylolytic and lactate-utilizing bacteria. Feces were collected from 3 mature geldings fed grass hay with access to pasture. Fecal microbes were harvested by differential centrifugation, washed, and re-suspended in anaerobic media containing ground corn, whe...
Muscher-Banse AS, Marholt L, Eigendorf N, Wilkens MR, Schröder B, Breves G, Cehak A.For horses, distinct differences in intestinal phosphate transport have been postulated to account for the unique features of hind gut fermentation compared to other monogastric animals and ruminants. So far published data on mechanisms and underlying transport proteins involved in intestinal phosphate transport in the horse are still missing. Therefore we investigated intestinal phosphate transport in horses at both functional and molecular levels. Segmental diversity of intestinal phosphate transport along the intestinal axis was documented using the Ussing chamber technique. A transcellular...
Sadet-Bourgeteau S, Philippeau C, Julliand V.Feeding a diet with a small amount of hay and a high proportion of concentrate given in large meals entails a risk of colic to horses as this can impact the hindgut microbial ecosystem. To counteract this potential negative effect, one feeding strategy is to modify the distribution sequence of concentrate and hay. The purpose of the present study was to assess the impact of feeding the concentrate meal before or with the hay meal on fermentative parameters postprandial variations in caecum and right ventral colon contents and faeces. We focused on the comparison of pH value and volatile fatty ...
Ericsson AC, Johnson PJ, Lopes MA, Perry SC, Lanter HR.Horses are exquisitely sensitive to non-specific gastrointestinal disturbances as well as systemic and extraintestinal conditions related to gut health, yet minimal data are available regarding the composition of the microbiota present in the equine stomach, small intestine, and cecum and their relation to fecal microbiota. Moreover, there is minimal information regarding the concordance of the luminal and mucosal microbial communities throughout the equine gut. Illumina-based 16S rRNA gene amplicon sequencing of the luminal and mucosal microbiota present in seven regions of the gastrointestin...
Yamada K, Sato F, Horiuchi N, Higuchi T, Kobayashi Y, Sasaki N, Nambo Y.Autopsy imaging (Ai), postmortem imaging before necropsy, is used in human forensic medicine. Ai was performed using computed tomography (CT) for a 1-month-old Thoroughbred foal cadaver found in a pasture. CT revealed pericardial effusion, collapse of the aorta, bleeding in the lung lobe, gas in the ventricles and liver parenchyma, and distension of the digestive tract. Rupture in the left auricle was confirmed by necropsy; however, it was not depicted on CT. Therefore, Ai and conventional necropsy are considered to complement each other. The cause of death was determined to be traumatic cardi...
Coverdale JA.Intensive management practices in the horse industry present a unique challenge to the microbiome of the large intestine. Common management practices such as high-concentrate diets, low forage quality, meal feeding, and confinement housing have an impact on intestinal function, specifically large intestinal fermentation. The microbiome of the equine large intestine is a complex and diverse ecosystem, and disruption of microbiota and their environment can lead to increased incidence of gastrointestinal disorder. Digestion in the horse can be improved through a variety of approaches such as feed...
Brøkner C, Austbø D, Næsset JA, Blache D, Bach Knudsen KE, Tauson AH.The hypothesis for this study was that a higher dietary proportion of soluble fibre would result in stable and constant plasma metabolite and regulatory hormone concentrations. The study was a 4×4 Latin Square design with a sequence of 17 days adaptation to the ration followed by 8 sampling days. The feed rations consisted of only timothy hay (H), hay plus molassed sugar beet pulp combined with either whole oats (OB) or barley (BB) and hay plus a loose chaff-based concentrate (M). Four horses were fitted with permanent caecal cannulas and liquid caecal content was withdrawn manually and blood...
Bełżecki G, Miltko R, Michałowski T, McEwan NR.This paper describes cultivation methods for ciliates from the digestive tract of horses. Members of three different genera were successfully grown in vitro for short periods of time. However, only cells belonging to the genus Blepharocorys, which resides in the horse's large intestine, were maintained for longer periods. This Blepharocorys culture was successfully grown in vitro after inoculation of freshly excreted horse faeces in culture medium containing a population of bacteria. The ciliates survived for over six months, and the density of their population varied between 1.7 × 10(3) and ...
Schaafstra FJ, van Doorn DA, Schonewille JT, Wartena FC, Zoon MV, Blok MC, Hendriks WH.Methodological aspects of digestibility measurements of feedstuffs for equines were studied in four Welsh pony geldings consuming four grass-hay diets in a 4 × 4 Latin square design. Diets contained either a low (L), medium (M), high (H), or very high (VH) ADF content (264, 314, 375, or 396 g·kg DM, respectively). Diets were supplemented with minerals, vitamins, and TiO (3.9 g Ti·d). Daily feces excreted were collected quantitatively over 10 consecutive days and analyzed for moisture, ash, ADL, AIA, and titanium (Ti). Minimum duration of total fecal collection (TFC) required for an accurate...
Miller MA, Moore GE, Bertin FR, Kritchevsky JE.Postmortem findings in 241 equids admitted to a teaching hospital that were at least 15 years old at autopsy were reviewed (1) to determine disease prevalence, (2) to compare the cause of death (or euthanasia) in equids 15 to 19 years of age (n = 116) with that in equids ≥20 years of age (n = 125), and (3) to catalog coexisting lesions in equids with pituitary pars intermedia dysfunction (PPID). Breed and sex were evenly distributed between the age groups. Death or euthanasia was attributed to disease of the digestive system (41.5%), pituitary gland (12.9%), locomotor system (10.0%), nervous...
Philippeau C, Sadet-Bourgeteau S, Varloud M, Julliand V.This study aimed at assessing the impact of four barley forms on total tract apparent digestibility of dietary fibre in horses fed a large amount of starch in the morning meal (0.27% BW). Processed barley forms had a greater pre-caecal starch digestibility than the whole form. Based on this result, we hypothesised that using barley-processing methods would limit the potential dumping of undegraded starch in the hindgut of horses and, consequently, the potential negative effect on fibre degradation in the hindgut. In a 4×4 latin square design, four mature geldings fitted with a right ventral c...
Hansen NC, Avershina E, Mydland LT, Næsset JA, Austbø D, Moen B, Måge I, Rudi K.It is well known that nutrient availability can alter the gut microbiota composition, while the effect on diversity and temporal stability remains largely unknown. Methods: Here we address the equine caecal microbiota temporal stability, diversity, and functionality in response to diets with different levels of nutrient availability. Hay (low and slower nutrient availability) versus a mixture of hay and whole oats (high and more rapid nutrient availability) were used as experimental diets. Results: We found major effects on the microbiota despite that the caecal pH was far from sub-clinical ac...
Decloedt AI, Bailly-Chouriberry L, Vanden Bussche J, Garcia P, Popot MA, Bonnaire Y, Vanhaecke L.Traditionally, steroids other than testosterone are considered to be synthetic, anabolic steroids. Nevertheless, in stallions, it has been shown that β-Bol can originate from naturally present testosterone. Other precursors, including phytosterols from feed, have been put forward to explain the prevalence of low levels of steroids (including β-Bol and ADD) in urine of mares and geldings. However, the possible biotransformation and identification of the precursors has thus far not been investigated in horses. To study the possible endogenous digestive transformation, in vitro simulations of t...
Destrez A, Grimm P, Cézilly F, Julliand V.The digestive system of horses is adapted to a high-fiber diet consumed in small amounts over a long time. However, during training, high-starch and low-fiber diets are usually fed which may induce hindgut microbial disturbances and intestinal pain. These diets can be described as alimentary stress. The aim of the present study was to investigate to what extent changes in behavior are associated with alimentary stress and microbial composition changes of the cecal or colonic ecosystem. Six fistulated horses were used. The alimentary stress was a modification of diet from a high-fiber diet (100...
Hagen KB, Tschudin A, Liesegang A, Hatt JM, Clauss M.It is generally assumed that animal species differ in physiological characteristics of their digestive tract. Because investigating digestive processes is often labour-intensive, requiring lengthy adaptation and collection periods, comparisons are often made on the basis of data collated from different studies. We added a new data set on dietary crude fibre (CF) and macromineral (Na, K, Ca, P, Mg) composition and apparent digestibility (aD) of organic matter (OM) and macrominerals in rabbits (Oryctolagus cuniculus; a total of 180 measurements with 12 individuals and 10 different diets) to a li...
John J, Roediger K, Schroedl W, Aldaher N, Vervuert I.Almost all foals develop transient diarrhoea within the first weeks of life. Studies indicated different viral, bacterial, and parasitic causes, such as rotavirus, Clostridium perfringens, Escherichia coli, and Cryptosporidium are discussed. But little is known about the development of intestinal microflora in foals. The present study investigated whether the supplementation with Bacillus cereus var. toyoi would modify the developing intestinal microflora and consequently reduce diarrhoea in foals. From birth, the foals were randomly assigned to three treatment groups: placebo (10 mL isotonic...
Pilo C, Altea A, Scala A.Gasterophilus larvae are common obligate parasites of the digestive tract of the equids. Horses become infected with this parasite by ingesting the larvae hatched from eggs laid by the female flies. In this study carried out monthly, we (i) counted the Gasterophilus eggs deposited by female flies on the coat of 30 grazing horses, (ii) counted and identified the Gasterophilus larvae retrieved from the digestive tract of 128 slaughtered horses, and (iii) compared these results to meteorological data. Eggs were deposited on all monitored horses, and were present from October to January and from M...
Zeyner A, Kirchhof S, Susenbeth A, Südekum KH, Kienzle E.Few data on apparent pre-caecal digestibility (APCD) of crude protein (CP) and particularly amino acids (AA) are available from studies with horses. Protein bound in cell walls (i.e. neutral detergent insoluble CP (NDICP)) is unlikely to be decomposed by digestive enzymes in the small intestine. In contrast the corresponding analytical fraction of neutral detergent soluble CP (NDSCP) (NDSCP = CP-NDICP) is likely to be available for auto-enzymatic digestion. A literature analysis on the relationship between NDICP/NDSCP and pre-caecal indigestible/digestible CP was carried out. There was a str...
Chiocchetti R, Giancola F, Mazzoni M, Sorteni C, Romagnoli N, Pietra M.The lower esophageal sphincter (LES) is a specialized, thickened muscle region with a high resting tone mediated by myogenic and neurogenic mechanisms. During swallowing or belching, the LES undergoes strong inhibitory innervation. In the horse, the LES seems to be organized as a "one-way" structure, enabling only the oral-anal progression of food. We characterized the esophageal and gastric pericardial inhibitory and excitatory intramural neurons immunoreactive (IR) for the enzymes neuronal nitric oxide synthase (nNOS) and choline acetyltransferase. Large percentages of myenteric plexus (MP) ...
Nedjadi T, Moran AW, Al-Rammahi MA, Shirazi-Beechey SP.The diet of the horse, pasture forage (grass), is fermented by the equine colonic microbiota to short-chain fatty acids, notably acetate, propionate and butyrate. Short-chain fatty acids provide a major source of energy for the horse and contribute to many vital physiological processes. We aimed to determine both the mechanism of butyrate uptake across the luminal membrane of equine colon and the nature of the protein involved. To this end, we isolated equine colonic luminal membrane vesicles. The abundance and activity of cysteine-sensitive alkaline phosphatase and villin, intestinal luminal ...
Glade MJ.Mature geldings at maintenance were fed different diets in a 4 x 4 Latin square design balanced to account for residual effects in an attempt to determine whether differences in the digestibility of the fibrous portions of feedstuffs would influence dietary nitrogen (N) requirements. Diet 1 contained corn and soybean meal (SBM); diet 2, corn, corn oil and urea; diet 3, corn, SBM, straw and urea; diet 4, corn, alfalfa and urea. Urea supplied 50% of the total N in diets 2 and 3 and 39% of the total N in diet 4. The diets were fed in amounts that met National Research Council (NRC) recommendation...
Fehlberg LK, Lattimer JM, Drouillard JS, Douthit TL.Effects of Co on fiber digestibility in horses are largely unknown. Our objective was to evaluate effects of Co chloride on in vitro gas production, VFA production, and dry matter (DM) disappearance (IVDMD) using cecal fluid from 4 cannulated Quarter Horses. Five grams DM of alfalfa or smooth bromegrass hay were provided as substrate with Co added at 0.0, 0.5, 5.0, 25.0, or 50.0 mg/kg substrate DM. Ten milliliters cecal fluid and 140 mL McDougall's buffer were incubated in duplicate, and pH, VFA concentrations, and IVDMD were measured after 48 hours. Gas production, used as an indicator of...
Ross MW, Rutkowski JA, Cullen KK.The myoelectric activity of the cecum and right ventral colon (RVC) was studied in 4 female ponies. Eight, bipolar Ag-AgCl electrodes were sequentially placed on the seromuscular layer of the cecum (6 electrodes) and RVC (2 electrodes), and recordings were begun 14 days after surgery. The myoelectric activity for each pony was recorded during 12, 60-minute recording sessions done during the interdigestive period (3 to 7 hours after the morning feeding). Coordinated series of spike bursts were recognized as independent motility patterns in the cecum and in the RVC. Local haustra-haustra myoelec...
Lorenzo-Figueras M, Preston T, Ott EA, Merritt AM.To evaluate the effect of ingestion of a high-carbohydrate versus a high-fat meal on relaxation of the proximal portion of the stomach and subsequent gastric emptying in horses. Methods: 6 healthy adult horses. Methods: The study consisted of 2 phases. In phase I, horses were offered a high-fat (8% fat) or a high-carbohydrate (3% fat) pelleted meal (0.5 g/kg) of identical volume, caloric density, and protein content. In phase II, meals consisted of a commercial sweet feed meal (0.5 g/kg) or this meal supplemented with corn oil (12.3% fat) or an isocaloric amount of glucose (2.9% fat). Proximal...
Fehlberg LK, Lattimer JM, Vahl CI, Drouillard JS, Douthit TL.Calcium salts of fatty acids (CSFAs) frequently are fed to ruminants, but their fate in the equine digestive system is unknown. The purpose of this study was to compare Enertia s/f, a proprietary CSFAs, and soybean (SB) oil with respect to impact on apparent total tract nutrient digestion and cecal fermentation parameters in horses. Eight cecally cannulated Quarter Horses were used in a crossover design in which horses consumed a diet for 32 d consisting of 1.5% body weight (BW) (as-fed) smooth bromegrass hay and 0.5% BW (as-fed) pelleted concentrate containing 4.9% CSFAs or 4.1% SB oil. Fecal...
Van Hoogmoed LM.Intestinal stasis or ileus is a significant cause of mortality and morbidity in horses and has been attributed to a variety of causes, including loss of intrinsic or extrinsic electrical activity, incoordination of contractile activity from regional stimuli, and dissociation between electrical and mechanical activity. Proposed mechanisms include systemic shock, electrolyte disturbances, persistent luminal distention, ischemia, inflammation, peritonitis, endotoxemia, and anesthesia. Because the cause of ileus is likely multifactorial, a variety of pharmaceutics have been used to target specific...
Errecalde JO, Button C, Baggot JD, Mulders MS.The pharmacokinetics and bioavailability of theophylline in horses were investigated following both intravenous and intragastric administration of aminophylline solutions at doses corresponding to 15 and 10 mg/kg theophylline base. A rapid distributive phase with a half-life of approximately 15-30 min was followed by a slower elimination half-life averaging 15-17 h. The apparent volume of distribution averaged 850-900 ml/kg. Theophylline, administered as aminophylline solution, was both rapidly and completely absorbed from the equine digestive tract. Based on the bioavailability and dispositio...
Santos AS, Ferreira LM, Martin-Rosset W, Cotovio M, Silva F, Bennett RN, Cone JW, Bessa RJ, Rodrigues MA.To access the fermentative response of equine caecal microbial population to nitrogen availability, an in vitro study was conducted using caecal contents provided with adequate energy sources and nitrogen as limiting nutrient. Two nitrogen (N) sources were provided, protein (casein) and non-protein (urea). Caecal fluid, taken from three cannulated horses receiving a hay-concentrate diet, was mixed with a N-free buffer-mineral solution. The influence of four N levels (3.7, 6.3, 12.5 or 25 mg of N in casein or urea) was studied using the gas production technique. Total volatile fatty acids (VFA)...
Meyer H, Flothow C, Radicke S.Three horses (approximately 190 kg BW) fitted with a permanent fistula at the end of the jejunum were used. To a control diet (1/3 hay, 2/3 mixed feed) one of two fat types (coconut fat or soybean oil) were added at 2 levels resulting in fat intakes of 0.1 g (control diet) to 0.5 or 1 g/kg BW 0.5 d, respectively. Each experimental period consisted of 2 weeks adaptation, 2 days of breath tests (before and hourly after the morning meal) and 5 days sampling of chyme. Crude fat, crude protein, concentrations of organic acids (SCFA, lactic acid), pH, and the minerals calcium, magnesium and phosphor...
Berreta A, Kopper JJ, Alexander TL, Kogan CJ, Burbick CR.Probiotics, by definition, are live micro-organisms and should remain viable when they reach the intended site of action which is typically the cecum and/or colon. In humans, probiotics often need enteric protection to survive transit through the proximal gastrointestinal (GI) tract. Typically, equine probiotics do not advertise enteric protection and to the author's knowledge the viability of equine probiotics after exposure to the proximal GI tract has not been evaluated. The objective of this study was to evaluate the effect of an in vitro simulation of the equine proximal GI tract on probi...
Glade MJ.Twelve adult horses were fed a corn-oats-timothy hay diet containing 2.87% nitrogen (N) for 4 wk and were then killed. Fresh digesta samples were immediately harvested from the stomach, duodenum, jejunum, ileum, cecum, large colon, small colon, rectum and feces. Total N content of the digesta (on a dry matter basis) increased from the stomach (2.74%) to the duodenum (5.58%; P less than .01), decreased in the cecum (3.10%, P less than .01), remained constant through the large intestine and decreased in the feces (2.10%; P less than .01). High-speed centrifugation of wet digesta and low-speed ce...
Suagee-Bedore JK, Linden DR, Bennett-Wimbush K, Splan RK.When fed to horses, high-starch diets elevate plasma concentrations of interleukin-1β (IL-1β) as soon as 1 hour posteating. This increase in IL-β is possibly because of changes in intestinal pH that result from rapid bacterial fermentation of starches and sugars in the digestive tract. The purpose of this research was to investigate the effect of feeding 0.9 kg of grass hay 30 minutes before feeding a concentrate meal on the postprandial rise in IL-1β, compared with control horses receiving the same concentrate without hay first. Six mature geldings were used in a switchback design. Hor...
Bockisch F, Taubert J, Coenen M, Vervuert I.The German Society of Nutrition Physiology has proposed a new protein evaluation system for horse feeds to estimate pre-cecally digestible crude protein (pcdCP) and amino acids (pcdAA) from chemical properties. A total of 71 feeds for horses were chemically tested and evaluated according to the new protein evaluation system. A feeding trial with eight horses tested whether differences in estimated pcdAA and neutral detergent soluble CP (NDSCP) in the diet were reflected by post-prandial (ppr) kinetics of plasma lysine (Lys) by feeding a complementary feed (control = CTRL) with 1.02 g Lys/100 k...
Peloso JG, Schumacher J, McClure SR, Crabill MR, Hanselka DV, Householder DD, Potter GD.A T-cannula was fitted permanently into the ileum of ten mature ponies to quantify the role of the prececal and postileal segments of the digestive tract in equine nutrition studies. The ponies were anesthetized, positioned in left lateral recumbency, and the distal small intestine was exteriorized through a right paralumbar incision. A silastic T-cannula was inserted through a 2-cm longitudinal incision into the lumen of the ileum, on the antimesenteric surface, and sutured to the ileum. The stem of the cannula was exteriorized through a 2-cm circular skin incision, 6 cm caudal to the 16th ri...
Nielsen MK, Martin AN, Scare JA, Steuer AE.Cyathostomins are pervasive parasites of equids across the world. Larval stages encyst in the mucosa of the cecum, ventral and dorsal colon and can induce an inflammatory response leading to larval cyathostominosis, a life-threatening generalized typhlocolitis. Mucosal digestion is the only gold standard procedure for identifying and quantifying all larval stages. There is a lack of standardization of this technique and several aspects are ambiguous, such as precision of the method and the possibility of spatial variation of mucosal larval counts. The aim of this study was to estimate precisio...
Minder HP, Merritt AM, Chalupa W.Feces from 13 healthy horses and 8 horses with chronic diarrhea were subjected to an in vetro fermentation procedure that had been developed for rumen fluid. Fermentations were conducted over 6 hours in a closed system, with and without an essential amino acid (EAA) mixture being added to the basic starch-buffer medium. The addition of EAA caused no significant difference in results of fermentation of feces from healthy horses. For diarrheic animals, there was a significant (P less than 0.01) increase in gas and total volatile fatty acids production whether EAA were present or not, and alpha-a...
Thorringer NW, Weisberg MR, Jensen RB.The competition for customers increases the search for new grain processing methods for equine feed, but the effect on starch digestibility and metabolic responses varies. Therefore, to evaluate the effect of the processing methods, toasting and micronizing, on starch digestion and the effect on metabolic responses, the mobile bag technique (MBT) and plasma glucose and insulin concentrations in the blood were used to estimate nutrient disappearance and metabolic responses pre-cecally. Further, cecal pH, ammonium nitrogen (N), and short-chain fatty acid (SCFA) concentrations were used to estima...
Muscher-Banse AS, Marholt L, Eigendorf N, Wilkens MR, Schröder B, Breves G, Cehak A.For horses, distinct differences in intestinal phosphate transport have been postulated to account for the unique features of hind gut fermentation compared to other monogastric animals and ruminants. So far published data on mechanisms and underlying transport proteins involved in intestinal phosphate transport in the horse are still missing. Therefore we investigated intestinal phosphate transport in horses at both functional and molecular levels. Segmental diversity of intestinal phosphate transport along the intestinal axis was documented using the Ussing chamber technique. A transcellular...
Rosenfeld I, Austbø D.Gastrointestinal retention time may affect digestive processes in the horse. To evaluate the effect of processing of grains on mean retention time in different segments of the gastrointestinal tract, 4 Norwegian Cold-blooded trotters (cecally cannulated, approximately 500 kg of BW) were used. Barley, maize, and wheat were all ground, pelleted, extruded, and micronized to create a total of 12 processed grains. After an adaptation period of 5 d, each horse was given 0.2 kg of Yb-mordanted grain together with their morning meal, which consisted of 2 kg of hay and 1 kg of one of the grains. Fecal ...
Nikles SA, Heath TJ.The intestine of horses differs from that of most other domestic animals in having a huge ascending colon and cecum, which together act as a large fermentation vat. The lymph drainage from this intestine occurs through a complex network of lymph vessels and lymph nodes, of which there are several thousand. The pathways taken by lymph through these vessels and nodes were studied by tracing injections of dye, by examining Microfil casts, and with light and transmission electron microscopy. Lymph vessels transporting lymph from the intestinal wall generally terminate on a single node within a gro...
Fintl C, Hudson NP.Gastrointestinal motility disorders are a serious problem in both veterinary and human medicine and may represent a dysfunction of the neural, muscular or pacemaker components (interstitial cells of Cajal) of bowel control. The interstitial cells of Cajal are considered to be the pacemakers and mediators of certain forms of neurotransmission in the gastrointestinal tract. These cells have been implicated, either primarily or secondarily, in the pathogenesis of gastrointestinal disease processes in which there is a prominent element of disturbance to intestinal motility. In the horse, their inv...
Giusto G, Gandini M, Amedeo S.To determine effects of staple size, precompression time, and tissue thickness on staple shape and tissue approximation in side-to-side jejunocecal anastomosis in equine specimens. Methods: Cecum, ileum, and jejunum specimens obtained from 18 healthy horses at an abattoir. Methods: Specimens were allotted into 2 groups. Anastomoses were stapled with 4.8-or 3.8-mm staples. Precompression time was 15 seconds for both groups. Staple lines were cut into proximal, middle, and distal sections. Thickness of intestinal walls was measured with a calibrated tissue micrometer, photographs were obtained, ...
Roger T, Bardon T, Ruckebusch Y.The electrical and mechanical activity of the digestive tract and its response to the administration of opiate agonists and antagonists was assessed from electrodes and strain gauges chronically implanted on the jejunum and the cecocolonic segments in 3 ponies given a diet of hay and concentrates. Before the drugs were given, 10 to 17 migrating myoelectric complexes/day were recorded on the small intestine, and a rhythmic motor activity (base line) was observed on the proximal portion of the colon at the rate of 3.5 to 6.6/hour. Propagated contractions from the proximal to the distal portion o...
Grev AM, Hathaway MR, Sheaffer CC, Wells MS, Reiter AS, Martinson KL.Reduced lignin alfalfa (Medicago sativa L.) has the potential to provide a higher-quality forage source for livestock by improving forage digestibility. This study was conducted to evaluate apparent digestibility when feeding reduced lignin and nonreduced lignin alfalfa hay to adult horses, and to examine mean fecal particle size (MFPS) and mean retention time (MRT) between alfalfa forage types. In 2017, reduced lignin ("54HVX41") and nonreduced lignin ("WL355.RR") alfalfa hay was harvested in Minnesota at the late-bud stage. Alfalfa hays were similar in crude protein (CP; 199 g/kg), neutral d...
Patton ME, Andrews FM, Bogers SH, Wong D, McKenzie HC, Werre SR, Byron CR.Ileus is a common life-threatening problem in horses, and currently available treatments may be ineffective. The purpose of this study was to determine whether bit chewing, a form of sham feeding, decreases the gastric emptying time (GET), small intestinal transit time (SITT), and total orocecal transit time (OCTT) in clinically normal horses in a prospective crossover study. Nine healthy horses were acclimated and fed a standardized diet. Following 24 h of fasting, self-contained video endoscopy capsules and acetaminophen were administered into the stomach via a nasogastric tube. Each horse u...
Muhonen S, Philippeau C, Julliand V.Horses are herbivores, and their hindgut functions as a fluid reservoir as forage fibre properties have great impact on the water content of digesta and the milieu in the ecosystem. Our objective was to compare the effect of grass fibre maturity and legume forage on the water-holding capacity (WHC) and viscosity of the equine hindgut and the body weight (BW) and fluid balance of horses. Three diets: concentrate and late harvested grass haylage (35:65 energy ratio) (C); early and late harvested grass haylage (80:20) (G); lucerne and late harvested grass haylage (80:20) (L) were fed to six caecu...
Crowhurst RC, Simpson DJ, McEnery RJ, Greenwood RE.Intestinal surgery in the foal is seldom necessary but some conditions in which it is essential are well recognized. The foal is a good surgical subject but success depends mainly on operating promptly before irreversible degenerative changes take place. Exploratory laparatomy is recommended whenever mechanical obstruction is suspected. Indications fall broadly into two main categories: 1. Cases arising from congenital defects. These form a miscellaneous group and present considerable difficulties in diagnosis and effective treatment. 2. Cases related to acute onset of obstruction, mainly due ...
Rosenfeld I, Austbø D, Volden H.Fecal samples were collected to evaluate mathematical models to describe the kinetics of digesta passage in the segments of the equine gastrointestinal tract and to compare the passage kinetics of hay and oats. Four Norwegian Cold-blooded trotters (cecally cannulated, approximately 500 kg of BW) were fed Cr-mordanted hay and Yb-marked oats with their morning meal. The meal consisted of 2 kg of hay and 1 kg of oats processed as ground, pelleted, extruded, or micronized. Each horse was fed each type of oats on different days of collection, after a 5-d adaptation period, in a 4 x 4 Latin square d...
Bergero D, Préfontaine C, Miraglia N, Peiretti PG.The digestibility of horse feeds and rations can be determined using different techniques such as calculations based on the chemical composition, in vivo or in vitro methods. The marker methods overcome difficulties like discomfort for the animals and longer experimental times encountered using the ingesta/egesta method. In field conditions, a natural indigestible marker like acid-insoluble ash (AIA), with no changes in the normal ration, could be a very useful tool for digestibility trials. A group of six standardbred horses was used in a set of seven apparent digestibility trials. The diets ...
Vervuert I, Bothe C, Coenen M.This study was conducted to evaluate the effects of different barley processing techniques on the glycaemic and insulinaemic responses in horses. It was hypothesized that the changes in pre-caecal starch digestibility caused by barley processing would affect metabolic responses. Six horses were fed in random order: whole (WB), finely ground (FGB), steamed (SB), steam-flaked (SFB) and popped barley (PB). The total barley intake was adjusted to 630 g starch/horse/day (1.2-1.5 g starch/kg BW/day). During a 10-day stabilization period, the horses also received 6 kg grass hay/horse/day. On the bloo...
