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.
Longland AC, Barfoot C, Harris PA.The digestibility and nutritive values of pastures that were either freely or strip-grazed for 28 days were compared. Twelve ponies were individually grazed in adjacent, 10 m wide, rectangular paddocks. On day -1, each paddock length was adjusted to contain a 28-day supply of herbage DM at 1.5 % of pony BW/d. Ponies, (4/treatment) either accessed the entire 28-day supply from day 1 (TA), or gradually via strip-grazing treatments, SG1 and SG2. SG1 had a 'lead' fence spanning the paddock width that from day 3 was moved forward 1/26th of the paddock length daily, whereas SG2 had an additional 'b...
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...
Zicarelli F, Tudisco R, Lotito D, Musco N, Iommelli P, Ferrara M, Calabrò S, Infascelli F, Lombardi P.Determination of digestibility represents the first step for the evaluation of the net energy content of feed for livestock animals. The aim of this study was to evaluate the in vivo digestibility and in vitro degradability of five diets characterized by different forage/concentrate ratios (F:C) in horses. The in vitro degradability was determined by the Gas Production Technique (GPT), using as an inoculum source the feces of the same subjects used for the in vivo test. Five diets consisting of poliphyte hay, straw and grains of barley and oats with a different F:C ratio [90/10 (Diet 1); 78/22...
Li J, Huang X, He L, Li C, Jing H, Lin J, Ma C, Li X.This study aimed to investigate the effects of EA supplementation on body weight, nutrient digestibility, fecal microbiota, blood biochemical indices, and urolithin A metabolism in one-year-old Thoroughbred horses. A group of 18 one-year-old Thoroughbred horses, with an average weight of 339.00 ± 30.11 kg, were randomly allocated into three groups of six horses each (three males and three females). The control group (n=6) received only the basal diet, whereas test groups I (n=6) and II (n=6) were fed the basal diet supplemented with 15 mg/kg BW/d and 30 mg/kg BW/d of EA, respectively, for ...
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...
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 ...
Elghandour MMY, Tan ZL, Abu Hafsa SH, Adegbeye MJ, Greiner R, Ugbogu EA, Cedillo Monroy J, Salem AZM.The production of livestock and poultry faces major challenges to meet the global demand for meat and dairy products and eggs due to a steady increase in the world's population and the ban of antibiotics in animal production. This ban has forced animal nutritionists to seek for natural alternatives to antibiotics. In this context, the yeast Saccharomyces cerevisiae has received considerable attention in the last decade. It has been reported that feed supplementation with live yeast cells improve feed efficiency, enhance feed digestibility, increase animal performance, reduce the number of path...
Harris PA, Ellis AD, Fradinho MJ, Jansson A, Julliand V, Luthersson N, Santos AS, Vervuert I.The horse is a non-ruminant herbivore adapted to eating plant-fibre or forage-based diets. Some horses are stabled for most or the majority of the day with limited or no access to fresh pasture and are fed preserved forage typically as hay or haylage and sometimes silage. This raises questions with respect to the quality and suitability of these preserved forages (considering production, nutritional content, digestibility as well as hygiene) and required quantities. Especially for performance horses, forage is often replaced with energy dense feedstuffs which can result in a reduction in the p...
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...
Flickinger EA, Van Loo J, Fahey GC.Inulin and oligofructose are prebiotic oligosaccharides fermented in the large intestine. This article provides an extensive review of the effects of these oligosaccharides on gastrointestinal characteristics (microflora, pathogen control, epithelial cell proliferation, putrefactive compound production, fecal characteristics, and nutrient digestibility) and systemic metabolism of carbohydrates, nitrogen, lipids, and minerals in dogs, cats, horses, calves, pigs, poultry, and rabbits. In addition, intake of inulin and oligofructose and considerations in their supplementation to animal diets are ...
Moore BE, Dehority BA.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 were obs...
Jouany JP, Gobert J, Medina B, Bertin G, Julliand V.Eight crossbred male horses aged 12 +/- 5 yr and with BW of 305 +/- 18 kg were used in pairs in a 4 x 4 Latin square design with 4 ground and pelleted diets. Each pair included a cecum and right ventral colon-fistulated animal and a cecal-fistulated animal. The 4 horse diets were a high-fiber diet (HF+0) based on dehydrated alfalfa, a high-starch diet based on barley and wheat bran (HS+0), and the HF or HS diets supplemented with Saccharomyces cerevisiae (SC) CBS 493.94 (HF+SC and HS+SC). The probiotic preparation contained 4.5 x 10(9) cfu/g of live yeast mixed with the culture medium, and was...
Pearson RA, Merritt JB.Four donkeys and four ponies maintained in climate rooms, were provided with meadow hay or barley straw supplemented with minerals and vitamins ad libitum. Both diets were given to all animals for periods of 21 days. Measurements were made during the last seven days following single doses of two non-absorbable markers (Cr-fibre and Co-EDTA). After six weeks the donkeys repeated the trial, walking 14 km and ascending 260 m five days per week. At rest ponies ate more than donkeys, however the donkeys showed a higher digestibility of dry matter (DM), organic matter (OM) and acid detergent fibre (...
Earing JE, Cassill BD, Hayes SH, Vanzant ES, Lawrence LM.The objective of this study was to determine if in vitro methodologies developed for the Ankom Daisy(II) incubator could produce accurate estimates of in vivo equine DM digestibility (DMD) and NDF digestibility (NDFD) when equine feces were used as the inoculum source. Four mature geldings were utilized in a 4 × 4 Latin square design experiment with a 2 × 2 factorial arrangement of dietary treatments (timothy hay, alfalfa hay, timothy hay plus oats, and alfalfa hay plus oats), in which the geldings were individually housed and fed. During each 5-d total fecal collection period, feces were co...
Adegbeye MJ, Elghandour MMMY, Barbabosa-Pliego A, Monroy JC, Mellado M, Ravi Kanth Reddy P, Salem AZM.Several concerns exist regarding horse rearing such as environmental pollution, antibiotics resistance, digestive disorders, mycotoxins contamination of animal feed, gut health management, and improvement of feed efficiency. Nanoparticles have the potential to address these issues and thus could be used as feed additive. Citrate reduces and stabilizes gold nanoparticles, alongside biosynthesized silver nanoparticles have the potential to prolong and improve digestive enzyme activity, which would enhance starch digestibility in the stomach. Zinc oxide and selenium nanoparticles could be used to...
Pastuszka R, Barłowska J, Litwińczuk Z.Protein content in cow milk (with over 20 proteins, and peptides may also occur as a result of enzymatic hydrolysis) ranges from 2.5% to 4.2% and is about 1.5-2 times higher than in human milk. Its most important allergens are considered to be β-lactoglobulin (absent in human milk) and αs1-casein. The most similar in composition to human milk is horse and donkey milk. It contains considerably more whey proteins (35-50%) than cow milk (about 20%), and the concentration of the most allergenic casein fraction αs1 is 1.5-2.5 g/l. In comparison, the content of αs1-casein in cow milk is about 10...
Swyers KL, Burk AO, Hartsock TG, Ungerfeld EM, Shelton JL.A study was conducted to determine whether direct-fed microbials (DFM) could be used to increase digestibility and minimize the risk of acidosis associated with feeding an increase in the amount of starch fed to horses. Fifteen mature Thoroughbred geldings were randomly assigned to 1 of 3 treatments in a 3 x 3 Latin square design balanced for carryover effects. Within each 26-d period, horses were offered grass hay + low-starch concentrate (LS; 1.2 g of starch x kg of BW(-1) x meal(-1)) from d 1 to 13 and then were abruptly changed to hay + high-starch concentrate (HS; 2.4 g of starch.kg of BW...
Elia JB, Erb HN, Houpt KA.The natural diet of free-ranging horses is grass, which is typically high in fiber and calorically dilute, however diets for high performance domestic horses are often low in fiber and calorically dense. The aim of the study was to determine the motivation of horses for hay when fed a low roughage diet. Their motivation could be used to determine if low roughage diets compromise the welfare of horses. Eight mares were fed two different diets in counterbalanced order: ad libitum orchard grass hay; a complete pelleted feed (pellets). Each trial lasted three weeks, with a one-week transition peri...
Ragnarsson S, Jansson A.The aim of the present study was to compare digestibility and metabolic response in Icelandic and Standardbred horses fed two grass haylages harvested at different stages of maturity. Six horses of each breed were used in a 24-day change-over design. A total collection of faeces was made on days 15-17 and 22-24. Blood samples were collected on day 24 of each period and analysed for total plasma protein (TPP), plasma urea, non-esterified fatty acids, cortisol and insulin concentration. There were no differences in digestibility coefficients of crude protein, neutral detergent fibre or energy be...
Franz R, Soliva CR, Kreuzer M, Hummel J, Clauss M.It is assumed that small herbivores produce negligible amounts of methane, but it is unclear whether this is a physiological peculiarity or simply a scaling effect. A respiratory chamber experiment was conducted with six rabbits (Oryctolagus cuniculus, 1.57±0.31 kg body mass) and six guinea pigs (Cavia porcellus, 0.79±0.07 kg) offered grass hay ad libitum. Daily dry matter (DM) intake and DM digestibility were 50±6 g kg⁻⁰·⁷⁵ d⁻¹ and 55±6% in rabbits and 59±11 g kg⁻⁰·⁷⁵ d⁻¹ and 61±3% in guinea pigs, respectively. Methane production was similar for both species (0.2...
Tassone S, Renna M, Barbera S, Valle E, Fortina R.Successful studies on in vitro digestibility measurement of feedstuffs with fecal inoculum have been reported for horses, whereas data on donkeys are currently lacking. In this study, we evaluated the use of the Daisy Incubator for in vitro digestibility measurement of feedstuffs using donkey feces as source of microbial inoculum. The method was tested using seven feedstuffs commonly used in donkey diets (alfalfa, bromegrass, ryegrass, and timothy hays; wheat bran and wheat straw; barley grains). Feces were obtained from four female donkeys, and incubations were carried out at 1-week interva...
Argo CM, Dugdale AH, McGowan CM.The addition of hay soaking to current nutritional advice for weight loss management for equine obesity lacks clinical evidence. Twelve overweight/obese horses and ponies were used to test the hypothesis that feeding soaked hay at 1.25% of body mass (BM) daily as dry matter (DM) before soaking would elicit weight losses within the target 0.5-1.0% of BM weekly. Six animals were used to evaluate the impact of nutrient-leaching on the digestibility and daily intakes of dietary energy and nutrients. Soaked hay DM was corrected in accordance with the 'insoluble' ADF content of fresh and soaked hays...
Longland AC, Barfoot C, Harris PA.The aim of this study was to determine the amounts of water-soluble carbohydrate (WSC), WSC constituents and protein leached from a range of U.K. hays soaked according to common practice. Initial hay WSC content ranged from 123 to 230 g/kg dry matter (DM). Soaking the hays for up to 16 hours in water at a mean temperature of 8°C resulted in a mean loss of 27 per cent (range 6 to 54 per cent) of hay WSC. The mean percentage losses of WSC constituents were 24 per cent (range 14 to 31) for fructan, 41 per cent (range 21 to 70) for fructose, 45 per cent (range 28 to 100) for sucrose and 56 per ce...
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...
Lattimer JM, Cooper SR, Freeman DW, Lalman DL.Two experiments were conducted to evaluate the use of a closed system, fermentation apparatus (Daisy II incubator) and determine the effects of a yeast culture (YC) preparation (Saccharomyces cerevisiae) on in vitro microbial populations, diet digestion, and fermentation patterns in horses. In Exp. 1, 4 mature horses were fed a pelleted concentrate and alfalfa cubes in a 50:50 (%, as-fed) ratio. Fecal samples were taken from each horse to form the inoculum and placed in 4 separate incubation vessels. Twenty nylon bags (10 with 0.25 g and 10 with 0.50 g of the total mixed diet) were placed in e...
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 ...
Gibbs PG, Potter GD, Schelling GT, Kreider JL, Boyd CL.Mature ponies fitted with permanent ileal cannulas were used in a 3 X 3 Latin square experiment to quantify prececal, postileal and total tract digestion of hay protein. Coastal Bermuda grass (CB), containing 11.7% crude protein, and two qualities of alfalfa, containing 15.0% (low-protein alfalfa; LA) and 18.1% (high-protein alfalfa; HA) crude protein, were fed in coarsely chopped form at 2% of body weight daily. Total tract apparent digestibility of the N in HA (73.8%) was higher than that in CB (57.0%; P less than .05) and was slightly higher than that in LA (66.1%; P less than .10). Nitroge...
Meyer H, Radicke S, Kienzle E, Wilke S, Kleffken D, Illenseer M.In this study preileal starch digestibility of starchy feeds (oats, corn, barley, potatoes, manioc) was determined in seven jejunofistulated horses. The grains were fed whole (oats, corn), rolled (oats, barley), crushed, ground and expanded (corn); the potatoes were fresh, the manioc rolled. Ground corn was also fed in combination with amylase. The feeds were fed partly isolated or in combination with alfalfa meal or hay (Table 1). At least four horses with a cannula in the terminal jejunum were used for each diet. Two meals per day were offered at 12 h intervals. The starch intake was mostly ...
Clauss M, Schiele K, Ortmann S, Fritz J, Codron D, Hummel J, Kienzle E.Equid digestion is often conceptualized as a high-throughput/low-efficiency system, in particular compared with ruminants. It is commonly assumed that ruminants have an advantage when resources are limited; the effect of low food intake on digestive physiology of horses has, however, not been explored to our knowledge. We used four adult ponies [initial body mass (BM) 288 ± 65 kg] in two subsequent trials with grass hay-only diets [in dry matter (DM): hay1, mid-early cut, crude protein (CP) 10.5%, neutral detergent fibre (NDF) 67.6%; hay2, late cut, CP 5.8%, NDF 69.5%], each fed subsequent...
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...
