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.
Bochnia M, Boesel M, Bahrenthien L, Wensch-Dorendorf M, Zeyner A.The aim of the study was to compare diverse feed intake patterns in sport ponies and warmblood-type horses after feeding iso-energetic amounts of three different concentrates: a pelleted fibre-rich mixed feed (PF), a muesli feed (MF) and semicrushed oat grains (OG). Four sport ponies and six warmblood-type horses received the concentrates and meadow hay according to maintenance (0.52 MJ metabolizable energy (ME) kg body weight (BW) /day). Both breeds were allocated at random to three groups and received once daily for 8 days either OG (1 g starch/kg BW/meal) or iso-energetic quantities of ...
Schaafstra FJWC, van Doorn DA, Schonewille JT, van Riet MMJ, Visser P, Blok MC, Hendriks WH.Methodological aspects of digestibility measurements were studied in four Welsh pony geldings consuming haylage-based diets with increasing proportions of a pelleted concentrate according to a 4×4 Latin square design experiment. Ponies were fed four experimental, iso-energetic (net energy (NE) basis) diets (i.e. 22 MJ NE/day) with increasing proportions of a pelleted concentrate (C) in relation to haylage (H). The absolute amounts of diet dry matter fed per day were 4.48 kg of H (100H), 3.36 and 0.73 kg of H and C (75H25C), 2.24 and 1.45 kg of H and C (50H50C) and 1.12 and 2.17 kg of H and C ...
Faubladier C, Julliand V, Beuneiche L, Philippeau C.Total tract apparent digestibility of dietary fibrous components and parameters of the faecal digestive ecosystem were compared at immediate and late post-weaning periods using five foals. The foals were abruptly weaned (day 0) from their mares at 6 months of age. Immediately (day 0 to day 14) and later (day 131 to day 194) after weaning, foals received the same basal diet consisting of hay and pellets. Pellets were fed at 0.36% BW. Hay was offered ad libitum and corresponded to 120% of the average voluntary hay intake measured individually during the immediate (days 1 to 4) and late (days 180...
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...
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...
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...
Huntley NF, Naumann HD, Kenny AL, Kerley MS.The domestic horse is used as a nutritional model for rhinoceros maintained under human care. The validity of this model for browsing rhinoceros has been questioned due to high prevalence of iron overload disorder (IOD) in captive black rhinoceros (Diceros bicornis), which is associated with high morbidity and mortality. Iron chelators, such as tannins, are under investigation as dietary supplements to ameliorate or prevent IOD in prone species. Polyphenolic compounds variably affect microbial fermentation, so the first objective of this experiment was to evaluate the effects of grape seed ext...
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...
Fowler AL, Hansen TL, Strasinger LA, Harlow BE, Lawrence LM.Inorganic P is often added to growing horse diets because organic P, or phytate-P, is believed to have lower digestibility. If horses can efficiently digest organic P, then the need for inorganic P may be reduced. Much of the P in grain-based concentrates fed to growing horses is in the form of phytate-P. Little is known about the ability of growing horses to degrade phytate-P or whether horse age affects mineral digestion in horses. The objective of this study was to examine the effect of age on P, Ca, and Mg digestibility as well as phytate-P degradation. Four yearling geldings and 4 mature ...
Schaafstra FJ, van Doorn DA, Schonewille JT, Wartena FC, Zoon MV, Blok MC, Hendriks WH.Methodological aspects of digestibility measurements of feedstuffs for equines were studied in four Welsh pony geldings consuming four grass-hay diets in a 4 × 4 Latin square design. Diets contained either a low (L), medium (M), high (H), or very high (VH) ADF content (264, 314, 375, or 396 g·kg DM, respectively). Diets were supplemented with minerals, vitamins, and TiO (3.9 g Ti·d). Daily feces excreted were collected quantitatively over 10 consecutive days and analyzed for moisture, ash, ADL, AIA, and titanium (Ti). Minimum duration of total fecal collection (TFC) required for an accurate...
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...
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...
López López C, Celaya R, Santos AS, Rodrigues MA, Osoro K, Ferreira LM.Utilization of long-chain alcohols (LCOH) as diet composition markers in horses and cattle was assessed in a study conducted with 12 mature crossbreed mares (385±47 kg BW) and six adult non-lactating cows (499±36 kg BW) of Asturiana de los Valles breed. The LCOH data were combined with alkane and long-chain fatty acid (LCFA) data to test the applicability of combining these markers to estimate diet composition. Animals were randomly divided into groups of three animals and received a daily total amount of 1.0 kg dry matter/100 kg BW of diets composed of different proportions of ryegrass (Lol...
Dansen O, Pellikaan WF, Hendriks WH, Dijkstra J, Jacobs MP, Everts H, van Doorn DA.Methane production from Welsh ponies fed 2 isoenergetic diets (NE basis) at maintenance was studied in a crossover design with 4 mature geldings (230 ± 10.5 kg BW, mean ± SE). Treatments included a roughage-only (R) diet (5.1 kg DM/d) or a roughage plus cereal mix (RC) diet (2.5 kg DM hay/d plus 1.1 kg DM cereal mix/d). For both diets, the same grass hay was used (898 g DM/kg and 4.5 MJ NE/kg DM) and a commercial cereal mix was used in the RC diet (890 g DM/kg and 9.6 MJ NE/kg DM). Ponies were housed in pairs in climate-controlled respiration chambers. Carbon dioxide production (CO2), oxygen...
Collas C, Dumont B, Delagarde R, Martin-Rosset W, Fleurance G.Little is known about how to manage grazing horses, including the thresholds under which energy supplementation is required. Here we investigated the effects of daily herbage allowance (DHA) and energy supplementation (ES) on daily herbage intake in lactating mares of light breeds grazing high-quality regrowth during summer. Three contrasting DHA, low (LOW), medium (MED), and high (HIGH), that is, 35.0, 52.5, and 70.0 g DM∙kg BW(-1)∙d(-1), respectively, were obtained by adjusting pasture strip width. Eighteen Anglo-Arab and French Saddle lactating mares were either supplemented with 2.6 kg...
Hagen KB, Tschudin A, Liesegang A, Hatt JM, Clauss M.It is generally assumed that animal species differ in physiological characteristics of their digestive tract. Because investigating digestive processes is often labour-intensive, requiring lengthy adaptation and collection periods, comparisons are often made on the basis of data collated from different studies. We added a new data set on dietary crude fibre (CF) and macromineral (Na, K, Ca, P, Mg) composition and apparent digestibility (aD) of organic matter (OM) and macrominerals in rabbits (Oryctolagus cuniculus; a total of 180 measurements with 12 individuals and 10 different diets) to a li...
Zeyner A, Kirchhof S, Susenbeth A, Südekum KH, Kienzle E.Few data on apparent pre-caecal digestibility (APCD) of crude protein (CP) and particularly amino acids (AA) are available from studies with horses. Protein bound in cell walls (i.e. neutral detergent insoluble CP (NDICP)) is unlikely to be decomposed by digestive enzymes in the small intestine. In contrast the corresponding analytical fraction of neutral detergent soluble CP (NDSCP) (NDSCP = CP-NDICP) is likely to be available for auto-enzymatic digestion. A literature analysis on the relationship between NDICP/NDSCP and pre-caecal indigestible/digestible CP was carried out. There was a str...
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...
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 ...
Obitsu T, Hata H, Taniguchi K.Nitrogen (N) digestion and urea-N metabolism in Hokkaido native horses fed roughage-based diets containing different types and levels of protein sources were studied. Horses (173 ± 4.8 kg) fitted with an ileum cannula were fed four diets consisting of 100% timothy hay (TH), 88% TH and 12% soybean meal (SBM), 79% TH and 21% SBM, and 51% TH and 49% alfalfa hay at 2.2% of body weight. Dietary protein content varied from 5% to 15% of dry matter. Apparent N digestibilities in the pre-cecum and total tract for the TH diet were lower than those for other diets. However, the proportion of post-ileum ...
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 ...
Philippeau C, Varloud M, Julliand V.To determine prececal starch digestibili-ty and estimate glucose uptake from the digestion of 4 forms of barley in the small intestine, 4 mature cecally fistulated geldings (449 ± 41 kg BW) fed a 62:38 (wt/wt) meadow hay:concentrate diet at 1.7 kg DM/100 kg BW were included in a 4 × 4 Latin square design experiment. During each period, horses received 80% DM of their concentrate as 1 of the 4 forms of a same batch of barley, whole grain, 2.5 mm ground, steam flaked, and pelleted. Hay was offered in 2 equal meals and concentrate in 2 unequal meals. The starch supply in the morning meal amount...
Miyaji M, Ueda K, Hata H, Kondo S.Eight Thoroughbred horses were used to examine the effects of grass hay intake on the fiber digestion and the retention time of digesta in the total gastrointestinal tract and the hindgut segments. The horses were randomly assigned to 2 groups and offered 2.0 (high intake [HI]) or 1.3 kg DM/(100 kg BW • d; low intake [LI]) of timothy hay in equal amounts every 3 h for 17 d. The digestibility and total tract mean retention time of digesta (tMRT) in the total gastrointestinal tract were measured from d 11 to d 15. To measure the mean retention time of digesta in each hindgut segment (sMRT), th...
Goachet AG, Harris P, Philippeau C, Julliand V.This study aimed at evaluating, in previously inactive Standardbreds horses, the effect of 5 weeks of an exercise training programme on nutrient digestibility and faecal fermentative parameters (FFPs). As an increase in digestibility had previously been reported in trained endurance horses, we hypothesized that similar results would be found in horses being trained for other types of exercise on a different type of diet. After 3 weeks of dietary adaptation, a digestibility trial (DT1) was undertaken, over 3 days, in eight untrained Standardbreds with a fresh faecal sample being collected on th...
De Marco M, Peiretti PG, Miraglia N, Bergero D.The aim of this study was to assess the apparent digestibility of broken rice using total collection of feces and the pepsin-cellulase in vitro technique to provide updated and more accurate digestion coefficients for this by-product when fed to horses. The in vivo digestibility trial was consecutively performed, using five adult geldings, weighing 555.6 kg on average. First, hay was given as the only feedstuff, while second, the experimental diet consisted of the same hay plus broken rice at a forage-to-concentrate ratio of 70/30 (on dry matter (DM) basis). Feces were collected over 6 days pr...
Gordon ME, Edwards MS, Sweeney CR, Jerina ML.The objective of this study was to test the hypothesis that feed additives such as chelated minerals, organic Se, yeast culture, direct-fed microbials, and Yucca schidigera extract would improve nutrient digestibility when included in an equine diet. Horses (Quarter Horse geldings 4.5 to 16 yr of age; mean BW 522 kg ± 46 kg) were acclimated to 100% pelleted diets formulated with (ADD) and without (CTRL) commercially available sources of the aforementioned additives followed by a 14-d collection period of feces and urine. Chelated sources of Cu, Zn, Mn and Co were utilized versus sulfated form...
Winsco KN, Coverdale JA, Wickersham TA, Lucia JL, Hammer CJ.Thirty pregnant mares (538 to 695 kg BW; 4 to 19 yr of age) were used to evaluate the effects of plane of nutrition on DMI of hay and mare performance (BW, BCS, and rump fat) during the last third of pregnancy. Mares were divided into 4 blocks by their expected foaling date and randomly assigned within block to either a hay or concentrate plus hay diet (concentrate fed at 0.75% BW, as-fed basis) with 15 mares per treatment. Treatments began 110 d before expected foaling date (230 d of gestation) and terminated at parturition. Mares were housed by block and allowed ad libitum access to coastal ...
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...
Goren G, Fritz J, Dillitzer N, Hipp B, Kienzle E.Hay stabilises urine pH in horses. It is unknown whether this is an effect of structure or of chemical composition. In this study, four ponies (230-384 kg body weight [BW]) were fed six different diets with either a structure or a composition similar to hay with and without acidifiers in a cross-over experimental design in amounts to maintain body weight with the following main compounds: Fresh grass (GRASS), alfalfa hay (ALF), grass cobs (COBS), grass silage (SIL), straw (STR) or extruded straw (STRe) for 2 to 10 days. Urine pH was measured in all trials, blood pH, blood base excess and bicar...
Lindberg JE, Karlsson CP.The objective of the present work was to assess the influence of partial replacement of oats with dried unmolassed sugar beet pulp (SBP) and/or maize oil on nutrient utilisation in horses fed a traditional hay and concentrate diet. The total tract digestibility of nutrients, urinary excretion and plasma parameters were studied in a 4 x 4 Latin-square design experiment with purebred Arabian geldings. Horses fed the SBP diets responded with a reduced (P<0.05) apparent digestibility of crude protein and feeding of maize oil resulted in an increased (P<0.05) apparent digestibility of crude f...
Jansen WL, Geelen SN, van der Kuilen J, Beynen AC.The aim of the present study was to establish whether the inhibitory effect of fat feeding on fibre digestion has been underestimated due to the substitution of fat for corn starch. A high fat intake has been shown to lower total intestinal tract apparent digestibility of crude fibre in horses but, since fat was substituted for nonstructural carbohydrates, including starch, the specific effect of fat could not be ascertained. The possibility could not be excluded that starch also inhibits fibre digestibility, so that the fat effect observed earlier would have been underestimated. In this study...
Fleurance G, Duncan P, Fritz H, Gordon IJ, Grenier-Loustalot MF.The spatial heterogeneity of grasslands determines the abundance and quality of food resources for grazing animals. As plants mature, they increase in mass, which allows greater instantaneous intake rates, but the cell wall concentrations increase too, reducing diet quality. In ruminants, daily intake rates are often constrained by the time needed for the ingesta to pass through the rumen, which is influenced by the rate of digestion. It has been suggested that the digestive constraint should have much less effect on hindgut fermenters such as equids. Horses play an increasing role in the mana...
Martin RG, McMeniman NP, Norton BW, Dowsett KF.The dynamics of N metabolism in mature horses were investigated when they were fed on a low-N diet or the same diet supplemented with sufficient urea or soybean meal to meet their theoretical N requirements. There were no differences in DM, organic matter or neutral-detergent-fibre digestibilities for the three diets. N digestibilities and digestible-N intakes were similar for the urea- and soyabean-supplemented diets and very low for the low-N diet. For all three diets plasma urea was degraded in the digestive tract to NH3 which was utilized by the bacterial population as a N source. NH3 was ...
Vervuert I, Coenen M, Bothe C.This study was conducted to evaluate the effects of different corn processing techniques on the glycaemic and insulinaemic responses in horses. It was hypothesized that the changes in pre-caecal starch digestibility caused by various types of corn processing would alter the post-prandial glycaemic and/or insulinaemic response. Six horses were fed in random order: untreated, finely ground, steamed, micronized, steam-flaked and popped corn. The total corn intake was adjusted to 630 g starch/horse/day (1.2-1.5 g starch/kg BW/day). During a stabilization period of 10 days, horses also received 6 k...
Cí·¯ord D.Artificially dehydrated lucerne produced in the United Kingdom has been shown to be a better source of nutrients for horses than grass hay. Horses eat more lucerne when it is pelleted, and the processing has little effect on its nutritive value. Lucerne does not appear to contain any antinutritional factors of significance to horses. Lucerne contains readily available calcium and protein and can thus be used as a cereal-balancer or to upgrade poor quality roughages. Because lucerne is a good source of digestible nutrients it has therapeutic applications, including the correction of electrolyte...
Laut JE, Houpt KA, Hintz HF, Houpt TR.In order to determine if horses will increase their intake in response to caloric dilution, four pony geldings were fed ad lib a mixed grain diet either undiluted (3.4 Mcal/kg of digestible energy) or diluted (wt/wt) with 25% sawdust (2.6 Mcal/kg) or with 50% sawdust (1.7 Mcal/kg). The mean daily caloric intake was 17,457 kcal (3.4 Mcal diet), 17,546 kcal (2.6 Mcal diet) and 12,844 kcal (1.7 Mcal). The mean time spent eating was 246 (3.4 Mcal), 351 (2.6 Mcal), and 408 (1.7 Mcal) minutes/day. Meal size increased and meal frequency decreased with increasing dilution. The median long survivorship...
Jansen WL, van der Kuilen J, Geelen SN, Beynen AC.The hypothesis tested was that the intake of extra fat at the expense of an isoenergetic amount of nonstructural carbohydrates reduces fibre utilisation in horses. In a crossover trial with feeding periods of 42 days each, 6 mature trotting horses (age 4-12 years, bodyweight 340-476 kg) were given either a control or test diet. The test concentrate was formulated to contain 37% of net energy in the form of soybean oil. The control concentrate contained an isoenergetic amount of corn starch plus glucose. The concentrates were fed in combination with the same amount of hay so that the control an...
Siciliano PD.Little is known regarding nutrient requirements and feeding of geriatric horses, and more effort should be placed on this area of equine nutrition research. That which is known suggests that some geriatric horses may not have different requirements than other mature horses, whereas others affected by disease or poor dentition may have special nutritional needs. In general, rations for geriatric horses should be based on high-quality roughage supplemented with complementary minerals and vitamins. The need for additional energy aside from that provided by the forage can be supplied by adding ene...
Zwirglmaier S, Remler HP, Senckenberg E, Fritz J, Stelzer P, Kienzle E.In nine adult Warmblood horses with mild to moderate dental findings (no signs of discomfort during chewing), voluntary hay intake before and after dental correction was examined. In a second experiment, digestibility of feed and faecal particle size were determined (3 days of total faecal collection) before and after dental correction. During both digestion trials including a 3-day adaptation period, the amount of hay and concentrate (mixture of oats, barley and maize) was kept constant in each individual horse before and after dental correction. Voluntary hay intake in individual horses ra...
Flachowsky G, Kirchgessner M.The paper describes the energetic feed evaluation systems for ruminants, pigs, poultry and horses presently used in Germany. During the last ten years the "Ausschuss für Bedarfsnormen" (AfB; Committee of Nutrient Requirements) of the "Gesellschaft für Ernährungsphysiologie" (GfE, Society of Nutritional Physiology) introduced new recommendations for energy requirements of domestic animals including national and international references. The energetic requirements were factorially deduced (demand for maintenance and various performances) under consideration of partial efficiency of utilized m...
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...
Grace ND, Rogers CW, Firth EC, Faram TL, Shaw HL.To measure the nutritive value of pasture in terms of digestible energy intake (DEI) and dry matter (DM) digestibility, and the effects of increased calcium (Ca) intakes on apparent mineral absorption and bone characteristics in grazing weanling Thoroughbreds. Methods: DM intake (DMI) and DEI were determined in 16 weanling Thoroughbreds grazing pasture from their daily faecal DM output, measured over 8 days, divided by the DM indigestible fraction (1-digestible DM) determined in a 6-day digestibility trial. The DM, gross energy content, crude protein, soluble carbohydrate, acid detergent fibre...
Schaafstra FJ, van Doorn DA, Schonewille JT, Wartena FC, Zoon MV, Blok MC, Hendriks WH.Methodological aspects of digestibility measurements of feedstuffs for equines were studied in four Welsh pony geldings consuming four grass-hay diets in a 4 × 4 Latin square design. Diets contained either a low (L), medium (M), high (H), or very high (VH) ADF content (264, 314, 375, or 396 g·kg DM, respectively). Diets were supplemented with minerals, vitamins, and TiO (3.9 g Ti·d). Daily feces excreted were collected quantitatively over 10 consecutive days and analyzed for moisture, ash, ADL, AIA, and titanium (Ti). Minimum duration of total fecal collection (TFC) required for an accurate...
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...
van Doorn DA, van der Spek ME, Everts H, Wouterse H, Beynen AC.Literature data show conflicting results on the effect of feeding high calcium (Ca) levels on phosphorus (P) digestibility in ponies. None of the studies reported involved a dose response as to the effect of Ca intake on apparent P digestibility while keeping P intake constant. Thus, the influence of high dietary Ca level on apparent P digestibility was studied in balance trials by feeding six mature ponies three different Ca levels against a constant P intake. The ponies received 148, 316 and 535 mg Ca/kg BW/day with the low, intermediate and high Ca diet. Phosphorus intake was approximately ...
Bochnia M, Boesel M, Bahrenthien L, Wensch-Dorendorf M, Zeyner A.The aim of the study was to compare diverse feed intake patterns in sport ponies and warmblood-type horses after feeding iso-energetic amounts of three different concentrates: a pelleted fibre-rich mixed feed (PF), a muesli feed (MF) and semicrushed oat grains (OG). Four sport ponies and six warmblood-type horses received the concentrates and meadow hay according to maintenance (0.52 MJ metabolizable energy (ME) kg body weight (BW) /day). Both breeds were allocated at random to three groups and received once daily for 8 days either OG (1 g starch/kg BW/meal) or iso-energetic quantities of ...
Powell CD, Dhanoa MS, Garber A, Murray JMD, López S, Ellis JL, France J.Two models are proposed to describe atypical biphasic gas production profiles obtained from in vitro digestibility studies. The models are extensions of the standard Mitscherlich equation, comprising either two Mitscherlich terms or one Mitscherlich and one linear term. Two models that describe typical monophasic gas production curves, the standard Mitscherlich and the France model [a generalised Mitscherlich (root-) equation], were assessed for comparison. Models were fitted to 25 gas production profiles resulting from incubating feedstuffs with faecal from equines. Seventeen profiles displa...
Glade MJ.Mature geldings at maintenance were fed different diets in a 4 x 4 Latin square design balanced to account for residual effects in an attempt to determine whether differences in the digestibility of the fibrous portions of feedstuffs would influence dietary nitrogen (N) requirements. Diet 1 contained corn and soybean meal (SBM); diet 2, corn, corn oil and urea; diet 3, corn, SBM, straw and urea; diet 4, corn, alfalfa and urea. Urea supplied 50% of the total N in diets 2 and 3 and 39% of the total N in diet 4. The diets were fed in amounts that met National Research Council (NRC) recommendation...
Fehlberg LK, Lattimer JM, Drouillard JS, Douthit TL.Effects of Co on fiber digestibility in horses are largely unknown. Our objective was to evaluate effects of Co chloride on in vitro gas production, VFA production, and dry matter (DM) disappearance (IVDMD) using cecal fluid from 4 cannulated Quarter Horses. Five grams DM of alfalfa or smooth bromegrass hay were provided as substrate with Co added at 0.0, 0.5, 5.0, 25.0, or 50.0 mg/kg substrate DM. Ten milliliters cecal fluid and 140 mL McDougall's buffer were incubated in duplicate, and pH, VFA concentrations, and IVDMD were measured after 48 hours. Gas production, used as an indicator of...
Swartzman JA, Hintz HF, Schryver HF.The effects of dietary oxalic acid on absorption, excretion, and retention of calcium was determined in Shetland ponies in 2 experiments. In each experiment, the results of feeding a control diet consisting of oats, molasses, and a complete pelleted horse ration were compared with those of feeding the control diet plus 1% oxalic acid. The diets contained 0.6% calcium in the 1st experiment and 0.45% calcium in the 2nd experiment. Oxalic acid increased the fecal excretion of calcium and decreased calcium absorption. The endogenous fecal excretion of calcium determined in the 1st experiment, usin...
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...
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...
Hoffmann M, Steinhöfel O, Fuchs R.The digestibility of the crude nutrients of 6 rations on the basis of oat, hay and wheat straw (in one case a straw-concentrate mixture as sole feed) was compared at a nutrition level of 1.0 and 1.3 resp. with adult geldings of the species "Noble Crossbreed", adult pony geldings and wethers The energy concentration of the rations varied between 424 and 585 EFUcattle/kg DM, the crude fibre content between 17 and 25% of the DM. In the studied field, a good agreement between horse and pony could be ascertained as to the digestibility of the organic matter and NFE. There are partly considerable di...
Fehlberg LK, Lattimer JM, Vahl CI, Drouillard JS, Douthit TL.Calcium salts of fatty acids (CSFAs) frequently are fed to ruminants, but their fate in the equine digestive system is unknown. The purpose of this study was to compare Enertia s/f, a proprietary CSFAs, and soybean (SB) oil with respect to impact on apparent total tract nutrient digestion and cecal fermentation parameters in horses. Eight cecally cannulated Quarter Horses were used in a crossover design in which horses consumed a diet for 32 d consisting of 1.5% body weight (BW) (as-fed) smooth bromegrass hay and 0.5% BW (as-fed) pelleted concentrate containing 4.9% CSFAs or 4.1% SB oil. Fecal...
Ögren G, Holtenius K, Jansson A.This study examined the P balance and fecal P losses in growing Standardbred horses in training fed a forage-only diet with or without P supplementation and assessed the magnitude and proportion of the soluble, inorganic P (Pi) fraction in feces. Fourteen Standardbred horses (aged 20.0 ± 0.3 mo) adapted to ad libitum intake of grass forage containing 0.25% P were used in a crossover experiment investigating 2 dietary treatments with (high-P) and without (low-P) mineral supplementation for 6 d. Daily feed intake and refusals were weighed. Spot samples of feces were collected twice daily on d 4...
Fowler AL, Hansen TL, Strasinger LA, Harlow BE, Lawrence LM.Inorganic P is often added to growing horse diets because organic P, or phytate-P, is believed to have lower digestibility. If horses can efficiently digest organic P, then the need for inorganic P may be reduced. Much of the P in grain-based concentrates fed to growing horses is in the form of phytate-P. Little is known about the ability of growing horses to degrade phytate-P or whether horse age affects mineral digestion in horses. The objective of this study was to examine the effect of age on P, Ca, and Mg digestibility as well as phytate-P degradation. Four yearling geldings and 4 mature ...
