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Topic:Digestion
Digestion in horses involves a complex process that begins in the mouth and extends through the gastrointestinal tract, including the stomach, small intestine, and large intestine. Horses are non-ruminant herbivores with a digestive system adapted to a high-fiber diet primarily composed of forage. The process starts with mastication, where food is mechanically broken down by the teeth and mixed with saliva to aid in swallowing. In the stomach, enzymatic digestion begins, but the majority of nutrient absorption occurs in the small intestine, where carbohydrates, proteins, and fats are broken down. The large intestine, including the cecum and colon, plays a significant role in fermenting fibrous plant material with the aid of a diverse microbial population, producing volatile fatty acids that serve as an energy source. This page aggregates peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and nutritional aspects of equine digestion, as well as the impact of diet and management practices on digestive health.
Molecular characterisation of carbohydrate digestion and absorption in equine small intestine. Dietary carbohydrates, when digested and absorbed in the small intestine of the horse, provide a substantial fraction of metabolisable energy. However, if levels in diets exceed the capacity of the equine small intestine to digest and absorb them, they reach the hindgut, cause alterations in microbial populations and the metabolite products and predispose the horse to gastrointestinal diseases. We set out to determine, at the molecular level, the mechanisms, properties and the site of expression of carbohydrate digestive and absorptive functions of the equine small intestinal brush-border memb...
The(13)C-octanoic acid breath test for detection of effects of meal composition on the rate of solid-phase gastric emptying in ponies. The aim of this study was to apply the(13)C-octanoic acid breath test for detection of alterations in the rate of solid-phase gastric emptying, induced by changes in test meal composition, in ponies. After a 14 hour fast the ponies (n = 4) ingested a test meal with 0, 35 or 70 ml soya oil, and labelled with 250 mg(13)C-octanoic acid. Each pony was given each of the three test meals on three separate occasions, in a randomised order. Exhaled breath samples were collected for 12 hours after ingestion of the test meal. Breath samples were analysed by continuous flow isotope ratio mass spectrometr...
Effect of dental correction on feed digestibility in horses. To test the hypothesis that routine dental correction (removal only of sharp hooks and points from molars and premolars) would improve digestion of a hay/grain ration whereas performance 'floats' (rounding and smoothing of the dental arcades) would adversely affect digestion, 8 mature horses free from dental correction for over a year were used. Five-day digestion trials were conducted before and 2 and 4 weeks after correction in all horses. Although all horses had sharp points and minor premolar hooks, none had severe dental abnormalities. There were no significant differences found in appare...
Six intestinal microflora-associated characteristics in sport horses. The aim of this study was to investigate 6 microflora-associated characteristics (MACs) in faecal samples from horses and to compare the results with baselines previously established in other mammals. A MAC is defined as any anatomical structure, physiological, biochemical or immunological characteristic in a host, which has been acted on by microorganisms. When the active microbes are absent, as in germ-free animals and healthy newborn organisms, the corresponding characteristic is defined as germ-free animal characteristic (GAC). The MACs studied were degradation of mucin, conversion of chol...
Phytate and phosphorus movements in the digestive tract of horses. This experiment was conducted to study phytate degradation and the effect of dietary phytate level on phosphorus absorption in the gastrointestinal tract of horses. Six Thoroughbred horses were fed diets containing low-phytate diet or high-phytate diet for 5 days. The diets were supplemented with Cr2O3 as an unabsorbable marker. The horses were killed 3 h after the last feeding and digesta in some segments of the intestine were collected. In both dietary groups, the daily passage of phytate phosphorus was decreased in the upper small intestine and in the lower large intestine. The daily passag...
[Nutrition of horses: digestion, energy and protein evaluation and nutritional standards]. The diet of horses should cover the energy and nutrient requirements of these animals. The desired composition of the ration depends on its digestion in the equine gastrointestinal tract. Nutritional problems or diseases caused by incorrect composition of the ration or by incorrect feeding should be prevented. The digestion of carbohydrates, fats, and proteins in the different parts of the gastrointestinal tract is described. In addition, the recently introduced net energy and digestible protein evaluation systems for feeds, and the energy and protein requirements of horses are presented.
Detection of equine herpesvirus types 2 and 5 (EHV-2 and EHV-5) in Przewalski’s wild horses. In blood samples of seven captive equid species from four German zoos EHV-1 specific antibodies were detected in 76% and EHV-4 specific antibodies in 73% of the 55 animals, whereas 93% were tested positive for EHV-2 and EHV-5, respectively. In only one blood sample from a Przewalski's wild horse EHV-4 DNA was amplified by PCR. From seven Przewalski's wild horses EHV-2, and from another one EHV-5 was isolated by cocultivation. The identity of the virus isolates was verified by PCR and restriction enzyme digestion.
Breath hydrogen measurement in ponies: a preliminary study. The aim of this study was to establish the normal patterns of breath hydrogen excretion in adult ponies following either voluntary consumption or administration per stomach tube of a test meal/carbohydrate substrate. After an overnight fast, the ponies (n = 7) received either no test meal (ie fasted), glucose, xylose, lactose, lactulose, wheat flour or oats. Exhaled breath samples were collected in duplicate at 0 minutes and at 30-minute intervals thereafter for eight hours. Analysis of duplicate breath hydrogen measurements (n = 714) indicated that the breath hydrogen collection/storage metho...
Calculation of fecal kinetics in horses fed hay or hay and concentrate. Marker methods are needed for estimating fecal output by grazing animals in studies of nutrition and environmental impact. In addition, estimates of prefecal mass and turnover time are relevant to exercise performance and certain digestive disorders. As a first step in developing marker methods for field use, a chromic oxide model of fecal kinetics was developed and tested in the context of a digestion balance experiment with stall-fed horses. The model consists of removal of feces at a constant rate from a single compartment, the prefecal mass. Four horses were fed hay, and another four were ...
Diseases and surgery of the cecum. The cecum is an important site of water and electrolyte absorption, as well as microbial digestion of soluble and insoluble carbohydrates. These functions of the cecum and ascending colon require that ingesta be mixed constantly and retained long enough to complete the digestion of cellulose. Parasites, changes in regional blood flow, diet, and various pharmacologic agents are associated with alterations in normal cecal motility patterns.
Morphology of starch digestion in the horse. Structure of starch in feed and chyme of horses (7 with a cannula at the caudal end of the jejunum and 2 with a cecal fistula) after feeding high starch diets (maize: whole, broken, ground, expanded and as silage, oats: whole, rolled or ground, rolled barley, raw potatoes, and tapioca) was investigated by light and electron microscopy. Structure of feed starch and morphology or starch degradation in the chyme corresponded to data on preileal starch digestibility which was investigated in a parallel study. Barriers for starch digestion in the gastrointestinal tract of the horse were structure o...
An evaluation of the use of cisapride in horses with chronic grass sickness (equine dysautonomia). A clinical trial was carried out to determine the effect of cisapride on rate of passage of digesta and clinical parameters in horses with chronic grass sickness. Sixteen horses were given intramuscular cisapride (0.1 mg kg-1 three times daily) (group I), and 15 received oral cisapride (0.8 mg kg-1 three times daily) (group O). A liquid-phase marker (cobalt-EDTA) and a solid-phase marker (polystyrene pellets) were given by stomach tube at the beginning of each of three consecutive 7 day periods, i.e., before, during and after cisapride therapy. Seven horses in each group completed the rate of ...
Methods for the Detection of Trichinellosis in Horses. Twelve horses were infected with various doses of Trichinella spiralis and then tested for infection using direct (artificial digestion) and indirect (enzyme immunoassay) methods. Horses became infected in a dose-dependent manner. Larvae accumulated preferentially in the tongue, followed by the masseter, neck, supraspinatus, trapezius, and diaphragm. At lower infection levels, the tongue harbored several times more parasites than were found in other tissues. The sensitivity of artificial digestion methods for detecting infections was directly related to sample size. One-gram samples were not r...
A review of recent research on nutrition and metabolism in the athletic horse. Although a lot of research has been directed at attempts to improve performance of the equine athlete, many of the studies reviewed herein did not show statistically significant improvements in race times or increased time to fatigue. However, it must be remembered that success in racing performances is not always measured in time, but by comparative lengths or even by a nose. Therefore, improvement in the ability of an individual equine athlete is not always measurable and success is most frequently determined by one animal being better than the others in a particular competition. Therefore, ...
Stability of penicillin G, ampicillin, amikacin and oxytetracycline and their interactions with food in in vitro simulated equine gastrointestinal contents. Penicillin G was extensively (84.7 per cent) and amikacin moderately (14.4 per cent) degraded when incubated for one hour in a chloride buffer at pH 1.9 designed to mimic the equine gastric pH. Ampicillin and oxytetracycline were stable at pH 1.9. Penicillin and ampicillin were moderately stable (more than 90 per cent) when incubated in equine caecal liquor for three hours but were degraded by about 65 per cent after 24 hours. More than 80 per cent of the initial concentrations of amikacin and oxytetracycline were recovered after 24 hours' incubation in equine caecal liquor. The concentrations...
Gastric emptying of solid, non-digestible, radiopaque markers in ponies. The gastric emptying of different forms of ingesta occurs by a variety of mechanisms and dysfunction may selectively affect different components of the gastric contents. A technique for assessing gastric emptying of solid, indigestible, radiopaque markers was developed. Emptying of these markers in four ponies was variable in both pattern and rate (half emptying time ranged from less than one hour to more than 24 hours). However, whereas in man physically similar markers appear to empty relatively rapidly when fasting but are delayed by a meal, no such delay was evident in these ponies. The ho...
Gastric emptying of four liquid meals in pony foals. Water, saline and a saline/Intralipid mixture (lipid concentration 1.25 per cent) emptied very rapidly from the stomach in neonatal pony foals, and obeyed an apparently exponential pattern. Cisapride did not significantly modify the emptying of the saline/Intralipid mixture. Equine milk emptied more slowly. The data indicated that the lipid component of milk was not an important factor. Milk caused deviation from an exponential pattern in two of four foals: an initial lag phase appeared, which could represent a phase of intragastric processing. However, the rate was still rapid compared with r...
Nutrition of the horse. The horse was domesticated around 2500 BC and has been used for work, pleasure, and companionship since that time. However, the percentage of time devoted to these endeavors has changed greatly. The number of horses in the US peaked at more than 26 million in 1918. Thereafter, the increasing use of the internal combustion engine caused a steady decline in the number of horses. By 1960, the US Department of Agriculture (USDA) estimated that there were only about 3 million horses in the US. In the 1960s, however, the number of...
[Trichinellosis in slaughtered and wild animals in Switzerland using a digestion method and a serologic method (E/S-ELISA)]. For many decades trichinellosis has not been reported among Swiss domestic pigs. Considering the fact that Trichinella occurs in a sylvatic cycle in Switzerland, a study was designed to reevaluate the present epidemiologic situation by investigating 10,904 fattening pigs, 218 pigs with free access to pasturage or being kept on an alp, 104 domestic boars, 106 horses, 44 wild boars and 538 foxes using a direct and an indirect diagnostic technique (digestion method and serology with ELISA and an excretory/secretory antigen, respectively). The digestion method was performed according to EC-guideli...
Effects of diet and hindgut defaunation on diet digestibility and microbial concentrations in the cecum and colon of the horse. The effects of diet and hindgut defaunation (removal of protozoa from the hindgut) on diet digestibility (Trial 1) and on total and cellulolytic bacterial and fungal concentrations in the cecum and colon (Trial 2) were investigated. A high-forage (HF) diet, 90% alfalfa hay-10% concentrate, or a higher-concentrate (HC) diet, 60% alfalfa hay-40% concentrate, was limit-fed. In Trial 1, defaunation resulted in a slight decrease in DM digestibility (P < .1) and had no effect on cellulose digestibility. Dry matter digestibility was higher (P < .001) with the HC diet; however, no differences we...
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 incubat...
Use of oral tolerance tests to investigate disaccharide digestion in neonatal foals. Oral tolerance tests were performed on 13 neonatal foals to determine their ability to digest disaccharides on d 1, 3 and 5 postpartum. Foals were assigned randomly to treatments consisting of 20% (wt/vol) solutions of either maltose, lactose, or sucrose, dosed at 1 g/kg of BW, or glucose, dosed at .5 g/kg of BW. After a 2-h fast, an initial blood sample was collected via jugular catheter. Foals were administered the appropriate solution orally, and blood was collected every 15 min for 1 h and then every 30 min for 3 h. Plasma glucose increased after dosing with lactose or glucose but not with...
Common horse sense. This research article corrects a common misconception about the energy metabolism in horses during short sprinting and long-distance running events, emphasizing that short sprints are primarily powered by anaerobic activity, [...]
[The effect of nutrition on the origin of colic (digestive disorders) in horses]. Colics are often initiated by mistakes in feeding inadequate feed quality or quantity or poor feeding technique. The consequences are obstruction, impaction or dysbiosis with increased production of organic acids, gas or toxins. Nutritional anamnesis in patients with colic may give information on the pathogenesis of the disease.
Equine myenteric plexus with special reference to the pelvic flexure pacemaker. Sellers et al. (1979, Am. J. Phys., 237: E457-E464) proposed a pelvic flexure pacemaker mechanism to account for the bidirectional contraction waves needed to both retain ingesta within the right ventral colon for cellulose digestion and terminal fermentation and to transport the digesta distad once the process has been completed. To corroborate the presence of a pelvic flexure pacemaker, we prepared whole mount samples of the tunica muscularis from 23 horses at ten sites along the large colon, cecum and jejunum. Following smooth muscle enzymatic digestion, somata of the myenteric plexus were ...
