Digestibility in horses refers to the process by which horses break down and absorb nutrients from their feed. It involves the mechanical and chemical breakdown of feed components in the digestive tract, enabling nutrient absorption into the bloodstream. Digestibility is influenced by various factors, including feed type, processing methods, and individual horse health. Commonly examined components include fiber, protein, starch, and fat, each requiring specific digestive processes. Research in this area often focuses on optimizing feed formulations and understanding the digestive efficiency of different feedstuffs. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms of digestion, factors affecting digestibility, and implications for equine nutrition and health.
Karasu GK, Rogers CW, Gee EK.Sustainability is the balancing act of optimizing the use of current resources without compromising the current or future environment. Within the agriculture sector the primary focus of sustainability has been to reduce environmental pollution, specifically greenhouse gasses (GHG) emissions, nitrogen emissions, and leaching. For the equine industry the first step towards sustainability is the documentation and critique of current feeding and management practices to permit modifications to enable the industry meet social and legislative obligations. As a monogastric hindgut fermenter on a per k...
de Medeiros Ferreira JR, Mello Cerbaro AE, Bastos FL, Pereira RA, Duarte MA, Araújo Júnior ÂMC, da Silva AH, de Oliveira Gobesso AA.High amounts of grains in the equine diet led to high starch intake, causing gut alterations. Aimed at reducing harmful effects, extract (MCE) is a phytogenic additive that stands out for its antibiotic and anti-inflammatory effects proven in different species. However, there is no useful information for horses. The objective of this study was to evaluate the effects of different levels of the inclusion of commercial MCE on body weight (BW), body condition score (BCS), total apparent digestibility (AD) of nutrients, faecal pH and fermentative products, on ponies fed a high-starch diet. Eight ...
Ögren G, Ragnarsson S, Jansson A.Knowledge of endogenous nutrient losses is important when estimating the nutrient requirements of animals. It has been suggested that faecal endogenous phosphorus (P) losses differ between growing and adult horses, but studies on foals are scarce. In addition, studies on foals on forage-only diets with different P contents are lacking. Thus this study: (1) assessed faecal endogenous P losses in foals fed a grass haylage-only diet close to or below estimated P requirements; (2) evaluated use of serum cross-linked carboxyterminal telopeptides of type-I collagen (CTx) as a marker of bone resorpti...
Muhonen S, Julliand V.Racing events challenge the fluid balance of athletic horses. The equine large intestine functions as a fluid reservoir, since the properties of dietary forage fibre affect the digesta water content and the milieu of this ecosystem. This study aimed to investigate the effect of grass maturity and legume forage on the faecal water-holding capacity (WHC) and microbial ecosystem, and the fluid balance and body weight (BW) of French trotters in race training. Six geldings were offered three diets with different fibre compositions: concentrate and late-harvested mature grass haylage (35:65 energy r...
Stang FL, Bjerregaard R, Müller CE, Ergon Å, Halling M, Thorringer NW, Kidane A, Jensen RB.Carbohydrates in forages constitute an important part of the feed ration for all horses. The aim of the present study was to investigate the effect of harvest time on carbohydrate composition and digestion of various grass species. The experiment was divided into three parts 1) characterization of the chemical composition of experimental feeds (6 grass species: meadow fescue [MF], cocksfoot [CF], perennial ryegrass [PR], smooth bromegrass [SB], tall fescue [TF], and timothy [TI], and 3 harvest times: early, medium, and late first cut), 2) measurements of the in vitro digestion of selected expe...
Perricone V, Sandrini S, Irshad N, Comi M, Lecchi C, Savoini G, Agazzi A.To support the overall health of horses, it is essential to maintain an optimal gut health (GH) status, which encompasses several physiological and functional aspects, including the balance and functionality of intestinal microbial populations and, accordingly, the effective digestion and absorption of nutrients. Numerous biotic and abiotic stressors can lead to an imbalance of GH, such as the quality of forages and the composition of diet, e.g., the inclusion of high energy-dense feeds to meet the energy requirements of performance horses. To support the digestive function and the intestinal ...
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...
Pisch C, Wensch-Dorendorf M, Schwarzenbolz U, Henle T, Greef JM, Zeyner A.Steaming hay is increasingly used to treat low-quality forage because it was proven to reduce inhalable allergens such as mould spores, bacteria, and airborne dust particles. Preliminary results have shown a substantial loss of precaecal (pc) digestibility (D) of crude protein (CP) and amino acids (AA). For this purpose, six different batches of hay from central Germany were divided into four subsamples, and each one was individually steamed. Native hay and four replicates of each steamed subsample were analysed for CP, AA, neutral detergent insoluble crude protein (NDICP), neutral detergent s...
Raspa F, Vervuert I, Capucchio MT, Colombino E, Bergero D, Forte C, Greppi M, Cavallarin L, Giribaldi M, Antoniazzi S, Cavallini D, Valvassori E....Horses are often fed high amounts of starch in their diets despite the well-established benefits of a fibre-based diet to promote gut health and animal welfare. The aim of the present study was to compare the effects of two different diets - one based on high amounts of starch (HS) vs. one base on high amounts of fibre (HF) - on specific parameters of the gut environment across different intestinal compartments of the horse digestive tract. To this end differences in the gastrointestinal environment between HS vs. HF fed horses were assessed in terms of dry matter, organic matter and ash conte...
Dockalova H, Baholet D, Batik A, Zeman L, Horky P.Milk thistle (Silybum marianum) provides several possible benefits for horses, namely anti-inflammatory, antioxidant effects, hepatoprotective, and neuroprotective effects. Silybin exerts also pronounced effects on energy metabolism, that could be useful for sport horses. The aim of this study is to evaluate the effect of milk thistle seed cakes (in the form of a granulated mixture with barley) on blood biochemical parameters (total protein, albumin, bilirubin, urea, creatinine, ALT, AST, ALP, GGT, LDH, the total cholesterol, HDL-cholesterol, LDL-cholesterol, TAG, BHB, NEFA, creatine kinase, l...
Fowler AL, Hayes SH, Crum AD, Lawrence LM.Titanium dioxide has been used as a marker for determining diet digestibility indirectly, but some authors have expressed difficulty in measuring TiO2 concentrations in fecal material. We developed an accurate and precise method to determine TiO2 concentrations in equine feces. The method includes dry-ashing samples, digestion with (NH4)2SO4 in concentrated sulfuric acid, followed by the addition of H2O2 to produce a yellow to orange color that can be read spectrophotometrically. Accuracy was tested by spike recovery, and precision was tested by examining the coefficient of variation (CV) betw...
Potter SJ, Bamford NJ, Baskerville CL, Harris PA, Bailey SR.Ponies and some horse breeds such as Andalusians exhibit an 'easy keeper' phenotype and tend to become obese more readily than other breeds such as Standardbreds. Various hypotheses have been proposed, including differences in appetite or metabolic efficiency. This study aimed to investigate the effect of breed on nutrient digestibility. Ponies, Standardbreds and Andalusian horses were adapted to consuming either a control fibre-based diet ( = 9), a hypercaloric cereal-rich diet ( = 12) or a hypercaloric fat-rich diet ( = 12) over 20 weeks. Total faecal collection was performed over 24 h to de...
Fujimori S.The cell walls of plants are mainly made of cellulose and contain a large number of calories. However, the main component, cellulose, is an indigestible plant fiber that is thought to be difficult for humans to use as energy. Herbivores acquire energy through the degradation of cell wall-derived dietary fiber by microorganisms in the digestive tract. Herbivores, especially horses, have a highly developed cecum and large intestine, and plants are fermented for their efficient use with the help of microorganisms. Humans also have an intestinal tract with a wide lumen on the proximal side of the ...
Weinert-Nelson JR, Meyer WA, Williams CA.Warm-season grasses have been suggested as alternative low non-structural carbohydrate (NSC) pasture forages. The purpose of this study was to evaluate nutrient composition and diurnal changes in soluble carbohydrates for the warm-season annual 'Quick-N-Big' crabgrass [CRB; Digitaria sanguinalis (L.) Scop.] and the warm-season perennial 'Wrangler' bermudagrass [BER; Cynodon dactylon (L.) Pers] in comparison to mixed cool-season grass [CSG; 'Inavale' orchardgrass (Dactylis glomerata [L.]), 'Tower' tall fescue (Lolium arundinaceum [Schreb.] Darbysh.), and 'Argyle' Kentucky bluegrass (Poa prat...
Saastamoinen M, Särkijärvi S, Suomala H.Six Finnhorse mares were used in a digestibility trial, in which six typical horse diets were compared. The diets were: (A) haylage 100%; (B) hay 100%; (C) hay 70% and oats 30%; (D) hay 70% and soybean meal + oats 30%; (E) hay 70%, rapeseed meal + oats 30% and (F) hay 70 %, linseed meal + oats 30%. The trial was conducted according to an unbalanced 6 × 4 Latin square design with four 3-week experimental periods. The experimental period consisted of 17-day preliminary feeding which was followed by a 4-day total faecal and urine collection periods to evaluate N excretion. The digestibilities of...
O'Donnell D, Sukovaty L, Webb G.This study evaluated the effect of storage conditions of equine fecal material on the viability of microbial inoculum used for in vitro equine digestibility trials. Pooled fecal material from three mature Quarter Horse geldings was stored at 39 °C anaerobically for 15 min (control), while aerobic samples were stored at 22 °C for 6 h (SC1), 3 °C for 6 h (SC2), and -18 °C for 24 h (SC3). Following storage, the feces were utilized to prepare microbial inoculum for the digestion of six different forages using the Daisy II Incubator. After incubation, DM, NDF, and ADF compositions were determin...
Vasco ACCM, Brinkley-Bissinger KJ, Bobel JM, Dubeux JCB, Warren LK, Wickens CL.Rhizoma peanut (RP, Arachis glabrata) hay has the potential to meet horses' crude protein (CP) requirements with less nitrogen excretion than other legumes. This study aimed to evaluate nutrient intake, apparent digestibility, and nitrogen balance of RP "Florigraze" hay compared with alfalfa (ALF, Medicago sativa L. "Legendary XHD") and bermudagrass (BG, Cynodon dactylon L. "Coastal") hays when fed to maintenance horses at 2% body weight/d on a dry matter (DM) basis. We hypothesized that nutrient intake would be comparable between the legume hays and lesser for BG and that RP would result in r...
Godwin T, Webb G, Lancaster P.Previous research indicates equine fecal inoculates produce comparable results to cecal fluid when used for in vitro procedures to analyze dry matter digestibility (DMD). Equine hindgut microbial communities represented in fecal samples have been shown to be affected by diet. The study's objective was to determine the effect of the donor diet on in vitro DMD when fecal donors were fed high starch, or high fiber diets. Six Quarter Horses were used in a crossover design to compare the effects of a grain versus forage diet on in vitro digestion of forages ranging from: CP 7.7 to 16.4 %DM, NDF 53 ...
Jurjanz S, Collas C, Quish C, Younge B, Feidt C.Data on soil ingestion in horses are lacking in contrast to other free-range animals. The importance of soil as a vector for environmental pollutants to food is less relevant in horses but several disorders secondary to soil ingestion, such as sand colic or enteritis have been reported. Therefore, soil ingestion has been studied on Irish sport horses grazing at three offered levels of daily herbage: 2, 3 and 4% of their body weight. Soil ingestion was estimated by the faecal recovery of a soil natural marker. Horses had 4.5, 4.1 and 3.7% of soil in their total intake respectively for the 2, 3 ...
Rodrigues PG, Garcez DSM, Silva CM, Santana CCS, Santana JCS, Lopes CDC, Muniz EN, de Oliveira Júnior GM, Silva de Moura R, de Souza JC.Forage palm is extremely suitable as animal fodder due to its high tolerance to the climatic rigors of the semiarid region and its ability to withstand the harsh physical-chemical limitations of poor soils. Thus, in this study, the effects of the partial replacement (0 %, 5 %, 10 % and 15 % replacement) of a molasses- or oat-based commercial concentrate with forage palm bran (FPB) on the acceptability, apparent digestibility and glycemic response of horses at maintenance were evaluated. The ratio of concentrate to roughage (Tifton 85 hay) was , and the dry matter (DM) intake was 2 %...
Kalantari RK, Rouzbehan Y, Fazaeli H, Direkvandi E, Salem AZM.The aim of this study was to investigate, the effect of different levels of concentrates and grain processing on feeding behavior, nutrient digestibility, fecal pH and blood metabolites in the horse. Sixteen 5 to 11 years old Turkmen horses with an initial body weight 433±50 kg were used in this experiment based on completely randomized design. Four treatments were studied, in three treatments were used 20, 25 and 30% of concentrate containing processed grains (A20, A25 and A30, respectively), and in one treatment was used 25% of concentrate containing whole grain (B25). The amount of feed in...
Dockalova H, Zeman L, Baholet D, Batik A, Skalickova S, Horky P.Milk thistle seeds contain a mixture of flavonoids known as silymarin, which consists of silybin, isosilybin, silychristine, and silydianin. Until now, there has been no evidence of monitoring the digestibility of silymarin complex in horses. The aim of the research was to evaluate the digestibility of silymarin complex and the effect of nutrient digestibility in horses. Different daily feed doses (FD) of milk thistle expeller (0 g, 100 g, 200 g, 400 g, 700 g) were administered to five mares kept under the same conditions and at the same feed rations. Digestibility of silymarin complex was mon...
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...
Spurgin CL, Coverdale JA, Leatherwood JL, Redmon LA, Bradbery AN, Wickersham TA.This study was conducted to determine the effects of forage crude protein () level on intake and digestion of Coastal bermudagrass hay by horses. Four cecally fistulated geldings were used in a 4 × 4 Latin square design with four treatments and four periods. Horses were fed one of four Coastal bermudagrass hays consisting of 7%, 10%, 13%, or 16% CP during each of the four 15-d periods. Intake and apparent digestibility were determined for each horse at the end of each period by total fecal collection. In addition, cecal fluid and blood samples were collected on the last day of each period for...
Bochnia M, Pietsch C, Wensch-Dorendorf M, Greef M, Zeyner A.Soaking hay before feeding has been documented to reduce airborn respirable particles and water-soluble carbohydrate (WSC) content which may have positive benefits for horses suffering from Equine Asthma (EA) or Equine Metabolic Syndrome (EMS). Prolonged soaking also leaches minerals, but to-date no measurement of the loss of small intestine digestible crude protein has been documented. One aim of this study was to investigate various soaking durations on nutrient contents of hay, WSC, macronutrients, and trace elements levels. Another objective was to determine the prececal digestible crude p...
Saeidi E, Mansoori Yarahmadi H, Fakhraei J, Mojahedi S.The objectives of this study were to determine the effects of dietary prebiotic fructooligosaccharides (FOS) from inulin and Enterococcus faecium on nutrient digestibility, fecal pH, and some blood parameters. In this experiment, twelve adult Kurdish horses with average bogy weight of 416 ± 43.3 kg and age averaging 6 ± 1.8 year were used in a replicated 4 × 4 Latin Square experiment with a 2 × 2 factorial design during 4 periods of 28 days, including 21 days for dietary adaptation and 7 days for sampling. Horses were offered 1 of 4 treatments: (1) no FOS or 2.5 × 10 colony forming ...
Direkvandi E, Rouzbehan Y, Fazaeli H.To determine the effects of feeding frequency on nutrient digestibility and blood metabolites in horse, 16 Turkmen horses were used with weight of 430 ± 46 kg and age of 7 ± 1.8 years. Four feeding frequencies with 2 (M2), 4 (M4), 6 (M6), and 8 (M8) meals per day were used for a period of 28 days. The ratio of hay to concentrate was 70:30 in the experimental diet. Acid insoluble ash was used as internal marker to determine digestibility. On the 27th day of experiment, the blood was collected on 13 time points throughout the day. The results of this experiment showed that feed intake was not ...
Martin-Rosset W, Andueza D, Vermorel M.The metabolisable energy (ME) content of feeds is a better estimate of their 'true' energy value than their digestible energy (DE) content, because ME takes account of the gross energy of methane (GEgas) and the gross energy of urine (GEurine) losses. The accuracy and precision of the Gesellschaft für Ernährungsphysiologie (GfE) and Institut National de la Recherche Agronomique (INRA) systems for predicting the DE and ME contents of diets for horses were compared using the results of a study comprising 15 mixed diets. The INRA system was more accurate than the GfE system for predicting DE, G...
Thorringer NW, Jensen RB.Total collection of faeces is considered the golden standard for estimating apparent total tract digestibility (ATTD) in horses. However, the evaluation of individual feedstuffs is limited and determination of nutrient digestibility in different segments of the gastrointestinal tract (GIT) is excluded. The rationale for performing this study was that the mobile bag technique (MBT) can provide information on individual feedstuffs' degradation, and the use of fistulated animals does provide additionally information regarding degradation in individual segments of the GIT. Recommendations for usin...
LaCasha PA, Brady HA, Allen VG, Richardson CR, Pond KR.Matua bromegrass (Bromus willdenowii Kunth. cv. Grasslands Matua) was introduced in 1973, but little information exists concerning its potential as a hay for horses. Thus, voluntary intake and apparent digestibility of OM, CP, and fiber components of Matua by 18 Quarter Horse yearlings (mean initial BW 354 kg; SE 5.8) were compared with alfalfa (Medicago sativa L.) and coastal bermudagrass (Cynodon dactylon L.) as hays in a randomized block design. A 15-d adjustment period was followed by a 5-d collection period during which the hays were consumed ad libitum. Voluntary intake of DM was greater...
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...
Pearson RA, Archibald RF, Muirhead RH.Four cattle, sheep, ponies and donkeys were fed dehydrated lucerne, early-cut hay, later-cut hay or barley straw in a Latin square-based design for four periods of 35 d. In the first sub-period animals were fed the diets ad libitum (1-21 d) and in the second sub-period they were fed the same diet restricted to 0.75 of ad libitum intake (days 22-35). Measurements of forage intake, apparent digestibilities and gastrointestinal mean retention times (MRT) were made in the last 7 d of each sub-period. Differences between species in voluntary DM intake (VDMI; g/kg live weight (LW)(0.75) and g/LW) we...
Kienzle E, Zeyner A.The development of a metabolizable energy (ME) system for horses is described. Predictive equations for gross energy and digestible energy (DE) are revisited. The relationship between feed protein content and renal energy losses and the relationship between feed fibre content and methane energy losses were analysed in a literature review to develop predictive equations for ME. In horses, renal energy losses are much higher than losses by methane energy. Renal energy losses were correlated more strictly to protein intake than to digestible protein intake. The reason probably is that per gram of...
Gomez A, Sharma AK, Grev A, Sheaffer C, Martinson K.Although contributions of the equine gut microbiome to forage utilization are well recognized, the impact of alfalfa (Medicago sativa L.) lignification on the equine gut microbiome remains unknown; thus, we characterized microbial communities in the equine gut when feeding reduced lignin (RL) and conventional (CON) alfalfa hays to adult stock-type horses. Dietary treatments were fed to six horses in a crossover study. Experimental periods consisted of a 9-day dietary adaptation phase followed by a 5-day total fecal collection phase, during which horses were housed in individual box stalls and ...
Hoskin SO, Gee EK.The feeding value of fresh pasture grazed in situ is determined by animal performance or productivity and could be relatively easily established for growing and lactating horses. Despite this, there is a lack of published information on the relative feeding value of different pastures and forages grazed by horses in New Zealand and the world. In addition, for adult breeding or non-breeding and young or adult sport or performance horses, the definition of feeding value and its determination remain problematic. Limited information suggests that the feeding value of perennial ryegrass-based pastu...
Shepherd ML, Ponder MA, Burk AO, Milton SC, Swecker WS.The purpose of the present study was to compare digestibility of grass hay, faecal and plasma volatile fatty acid (VFA) concentrations, and faecal bacterial abundance in overweight and moderate-condition mares. Five overweight adult mixed-breed mares and five adult mixed-breed mares in moderate condition were housed individually and limit-fed orchard grass (Dactylis glomerata) hay at 20 g/kg body weight (as fed) daily for 14 d. Forage DM and fibre digestibility were determined using AOAC methods; digestible energy was measured using bomb calorimetry; plasma and faecal VFA concentrations were ...
O'Connor CI, Nielsen BD, Woodward AD, Spooner HS, Ventura BA, Turner KK.Numerous studies suggest that silicon (Si) supplementation is beneficial for mineral metabolism and bone health. Mineral balance studies have not been performed in horses to determine how these supplements affect absorption of other minerals. The purpose of these studies was to investigate the effects of two different Si supplements on mineral absorption and retention in horses. Eight geldings were randomly placed in one of two groups: control (CO) or supplemental Si, which was provided by one of two supplements. The first, sodium aluminium silicate (SA), contains a bioavailable form of Si and...
Staniar WB, Bussard JR, Repard NM, Hall MH, Burk AO.The objective of this study was to evaluate nutrient composition, voluntary DMI, and apparent DM digestibility of teff hay cut at 3 different stages of maturity to evaluate its potential as a preserved forage for horses. Six mature Quarter Horse mares (12 +/- 3 yr; 553 +/- 39 kg of BW) were used in a replicated balanced Latin square design with 3 periods and 3 maturities of teff hay. Eragrostis tef ('Tiffany' teff) was planted in May and harvested at the boot, early-heading, or late-heading stage of maturity through the summer. Horses were acclimated to a mixture of maturities of teff hay for ...
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 ...
Udén P, Van Soest PJ.1. The abilities of cattle, sheep, goats, equines and rabbits to digest mature timothy (Phleum pratense) hay were compared. Apparent digestibilities were partitioned into true digestibility, metabolic faecal output (MFO) and fibre digestibility. The aid of the study was to determine the relative effects of fermentation site (among groups) and of body-weight (within groups) on the efficiency of digestion. 2. The ruminants were superior to equines, which were in turn superior to rabbits, in digesting fibre-components of the hay. A large individual variation in digestibility was noted only for th...
Edouard N, Fleurance G, Martin-Rosset W, Duncan P, Dulphy JP, Grange S, Baumont R, Dubroeucq H, Pérez-Barbería FJ, Gordon IJ.Food intake is a key biological process in animals, as it determines the energy and nutrients available for the physiological and behavioural processes. In herbivores, the abundance, structure and quality of plant resources are known to influence intake strongly. In ruminants, as the forage quality declines, digestibility and total intake decline. Equids are believed to be adapted to consume high-fibre low-quality forages. As hindgut fermenters, it has been suggested that their response to a reduction in food quality is to increase intake to maintain rates of energy and nutrient absorption. Al...
Kienzle E, Pohlenz J, Radicke S.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...
Zeyner A, Romanowski K, Vernunft A, Harris P, Müller AM, Wolf C, Kienzle E.The provision of NaCl, according to current recommendations, to horses in moderate work has been shown to induce immediate postprandial acidosis. The present study aimed to clarify whether this NaCl induced acidosis i) persists beyond the immediate postprandial period, and ii) is still present after a 2 week adaptation period. Six adult warmblood mares in moderate work received daily 1.00 kg hay per 100 kg body weight (bwt) only together with 0.64 kg unprocessed cereal grains/100 kg bwt.d as fed basis. Using a 3x3 Latin Square, either 0 (NaCl-0), 50 (NaCl-50) or 100 (NaCl-100) g NaCl/d were fe...
Hussein HS, Vogedes LA, Fernandez GC, Frankeny RL.Twenty geldings (five groups; similar age and BW) were used in a completely randomized design experiment to determine effects of grain supplementation of an alfalfa-cube diet on apparent nutrient digestibility and hindgut fermentation. The geldings were housed individually, fed their diets in two equal meals (0600 and 1800), and adapted to five dietary treatments over 6 wk. The treatments were alfalfa cubes (1% of BW; DM basis) without (control) or with one of four rolled cereal grains (i.e., barley, corn, naked oats, or oats) to provide a target level of 0.4% of BW as total nonstructural carb...
de Fombelle A, Veiga L, Drogoul C, Julliand V.This trial was conducted to determine the extent of prececal starch digestibility depending on the botanical origin of starch and on diet characteristics (i.e., composition and feeding pattern). The prececal disappearance of six substrates (oats, barley, corn, horse bean, potato, and wheat) was measured in four cannulated horses fed (as-fed basis) 11.8 g/kg BW of a high-fiber (HF) or high-starch (HS) pelleted feed and 10.0 g/kg BW of meadow hay using the mobile bag technique (MBT). The daily feeding pattern was either three meals (two meals of pellets and one meal of hay) or five meals (three ...
Palmgren Karlsson C, Jansson A, Essén-Gustavsson B, Lindberg JE.The aim of this study was to investigate the effect of partly replacing oats with molassed sugar beet pulp in a traditional hay/oat diet on nutrient utilisation and metabolic parameters in exercising horses. In a change-over experiment, 4 Standardbred geldings were fed a hay and oat-based diet (Oat diet) and a hay and oat-based diet where oats was partially replaced with molassed sugar beet pulp (MSBP diet). Each experimental period was 21 days during which total collection of faeces and urine was made and an exercise test (ET) performed. The crude fat digestibility was lower on the MSBP diet ...
Zeyner A, Geissler C, Dittrich A.To investigate effects of hay intake and feeding sequence on indicators of the microbial activity within the hindgut, six horses were fed 1.00 kg oats plus 0.50, 0.67, 0.83 or 1.00 kg hay/100 kg body weight (BW) x day, each for 14 days. Oats was offered either 30 min prior to hay (OA) or in the reversed sequence (HA) in a 2 x 8-week crossover design. Because typically exercised horses should be subjected to the study, faeces was used as substrate. Faecal dry matter (DM), the faecal waters' short-chain fatty acids (SCFA, in mmol/1) and molar percentages (mol%) of propionate and iso-butyrate wer...
The Journal of nutritionDecember 30, 1998
Volume 128, Issue 12 Suppl 2704S-2707S doi: 10.1093/jn/128.12.2704S
Pagan JD, Harris P, Brewster-Barnes T, Duren SE, Jackson SG.Most digestibility studies in horses have been conducted with idle horses confined to metabolism stalls. The values obtained from such studies are used for all classes of horses, including the performance horse. It has not been clearly established whether exercise affects digestibility. Olsson and Ruudvere (1955), summarizing a number of earlier studies, suggested that digestion may be affected in horses by work or exercise in such a way that it is improved by light exercise and inhibited by heavy work.
Orton et al. (1985) reported reduced retention time of a particulate marker in yearling ...
De Marco M, Miraglia N, Peiretti PG, Bergero D.Several studies have reported data on comparisons between two methods: the total collection of feces and the internal markers method. The aim of this study was to assess the apparent digestibility of two concentrates and to compare the apparent digestion coefficients using the total collection of feces and acid-insoluble ash (AIA) as the internal marker method. In 2009, six adult geldings aged between 3 and 11 years, with an average weight per trial of 543, 540 and 542 kg, respectively, were used to determine the apparent digestibility by means of three in vivo digestibility trials on hay, hay...
Clauss M, Castell JC, Kienzle E, Schramel P, Dierenfeld ES, Flach EJ, Behlert O, Streich WJ, Hummel J, Hatt JM.To test whether mineral recommendations for horses are likely to guarantee adequate mineral provision for black rhinoceroses (Diceros bicornis), we investigated the apparent absorption (aA) of macro- and microminerals in eight black rhinoceroses from three zoological institutions in a total of 32 feeding trials with total faecal collection, with additional data from three unpublished studies (18 feeding trials). Feeds and faeces were analysed for Ca, P, Mg, Na, K, Fe, Mn, Cu, Zn and Co. The resulting aA coefficients, and the linear relationships of apparently absorbable dietary mineral content...
Brøkner C, Austbø D, Næsset JA, Knudsen KE, Tauson AH.The working hypothesis was that a minor postprandial caecal pH decline would affect apparent total tract digestibility (ATTD) of the fibre fraction in horses and, hence, that soluble fibre would amplify fermentation and consequently increase ATTD of fibre. This 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 (Group H), hay plus molassed sugar beet pulp combined with either whole oats (Group OB) or barley (Group BB) and hay plus loose chaff based concentrate (Group M). Four hor...
Orton RK, Hume ID, Leng RA.Rates of passage of fluid and particulate digesta markers and apparent digestibility estimated by three methods were compared in yearling horses fed high (14 per cent) or low (8 per cent) crude protein diets with one of two levels of exercise (0 or 12 km trotting per day at 12 km/h). Mean retention times (MRT) of the fluid marker (51Cr-EDTA) were shorter than those of the particulate marker (ruthenium-phenanthroline). There were no significant effects of dietary protein level on passage of either marker or on apparent digestibility of dry matter. Exercise increased voluntary feed intake and ap...
Jensen RB, Austbø D, Bach Knudsen KE, Tauson AH.A total of four diets with different carbohydrate composition were investigated in a 4×4 Latin square design experiment with four Norwegian Coldblooded trotter horses. The objective of the present study was to increase the fermentable fibre content and reduce the starch intake of the total ration obtained by partly substituting mature hay and barley with sugar beet pulp (SBP), a soluble fibre source. The diets investigated were hay only (HAY), hay (85% of dry matter intake (DMI)) and molassed SBP (15% of DMI) (SBP), hay (68% of DMI) and barley (32% of DMI) (BAR), and hay (68% of DMI), barley ...
Doreau M, Boulot S, Bauchart D, Barlet JP, Martin-Rosset W.Voluntary food intake, milk yield and composition, and blood metabolites were measured during the first 2 mo of lactation in draft broodmares fed diets containing either 95% hay and 5% concentrates (Diet F) or 50% hay and 50% concentrates (Diet C). Voluntary food intake was higher for mares fed Diet C than for those fed Diet F (22.9 vs. 21.4 kg dry matter in wk 4). Both diets, especially Diet C, were eaten in amounts exceeding the energy requirements. Daily milk yield in wk 4 was 26.4 kg and 23.4 kg for mares fed Diets C and F, respectively. Milk fat and protein concentrations were higher (P l...
Moore-Colyer MJ, Hyslop JJ, Longland AC, Cí·¯ord D.An in sacco mobile bag technique was used to determine the rate and extent of disappearance of unmolassed sugar-beet pulp, soyabean hulls, hay cubes and an oat hull-naked oats mixture (67:33, w/w) in the foregut and total digestive tract of ponies. Ponies were administered naso-gastrically polyester mesh bags containing 350 mg feed, in a Latin square design. Bags were collected at the ileo-caecal junction (small intestine bag, SIB) and in the faeces (faecal bag, FB) and their residues analysed for proximate constituents and NSP composition and content. DM disappearances from individual bags we...
Mackenthun E, Coenen M, Vervuert I.Supplementation with Saccharomyces cerevisiae (SC) in horses may have some potential to modify microbial populations and thereby improve fibre digestibility. The aim of this study was to investigate the effects of SC on apparent total tract digestibility (ATTD) of nutrients, with a special focus on fibre digestion in healthy horses. The fermentation profile of microbial populations was another focus of interest. Twelve geldings were randomly assigned to three groups. The basal diet consisted of cracked corn (2 g starch/kg body weight [BW]) and hay (1.2 kg/100 kg BW). During adaptation (3 weeks...
Coverdale JA, Moore JA, Tyler HD, Miller-Auwerda PA.Soybean hulls have been successfully fed to ruminant animals as an economical substitute for hay. This feedstuff is a source of highly digestible fiber that does not contain starch. The purpose of this trial was to evaluate soybean hulls as a replacement fiber in horse diets. Four cecally cannulated Quarter Horse geldings, aged 6 to 10 yr and averaging 502 kg, were used in a 4 x 4 Latin square design with 21-d periods. Diets consisted of alfalfa/bromegrass hay (14.4% CP, 58.1% NDF, 39.1% ADF; DM basis) with the replacement of either 0, 25, 50, or 75% (as-fed basis) unpelleted soybean hulls (13...
Oliveira CA, Azevedo JF, Martins JA, Barreto MP, Silva VP, Julliand V, Almeida FQ.This study was performed to evaluate the impact of dietary protein levels on nutrient digestibility and water and nitrogen balances in conditioning eventing horses. Twenty-four Brazilian Sport Horses, male and female (8.0 to 15.0 yr; 488 ± 32 kg BW), were used in a randomized design with 4 levels of CP diets: 7.5%, 9.0%, 11.0%, and 13.0%. A digestion assay was performed with partial feces collection over 4 d, followed by 1 d of total urine collection. Data were submitted to regression analysis and adjusted to linear and quadratic models (P < 0.05). No differences were observed in the intake o...
Schultz CL, Lodge-Ivey SL, Bush LP, Craig AM, Strickland JR.To determine the amount of ergovaline and lysergic acid retained or excreted by geldings fed endophyte-infected seed containing known concentrations of these alkaloids, and the effects of exposure time on clinical expression of toxicosis. Methods: Mature geldings (n=10) received diets containing either endophyte-free (E-) or endophyte-infected (E+) tall fescue seed during three experimental phases. The first phase (Days -14 to -1) was an adaptation phase, to allow all horses to adapt to a diet containing E- tall fescue seed. The second (Days 0 to 3) was the initial exposure phase to E+ tall fe...
