Nutrition in horses encompasses the study of dietary requirements and feeding practices that support equine health, growth, and performance. It involves the analysis of nutrients such as carbohydrates, proteins, fats, vitamins, and minerals, and their roles in equine physiology. Proper nutrition is essential for maintaining optimal body condition, supporting metabolic processes, and preventing dietary-related disorders. Research in this field examines the nutritional needs of horses at different life stages and activity levels, as well as the effects of various feed types and supplements. This page compiles peer-reviewed research studies and scholarly articles that explore the composition, digestion, and impact of different dietary components on equine health and performance.
Mäenpää PH, Koskinen T, Koskinen E.Twenty mares and 15 foals of the Finnhorse breed were used to determine serum levels of vitamins A, E and D during different seasons. Monthly serum samples were analyzed from mares for 22 mo and from foals for 13 mo after birth. The horses were kept on pasture from early June until early October and in stables during the winter months. Seasonal differences (P less than .001) were found in serum retinol, retinol to protein ratio, alpha-tocopherol and alpha-tocopherol to cholesterol ratio. Values were lowest from February through May and highest from June through August. Serum levels of retinol ...
Groenendyk S, English PB, Abetz I.The components of the daily external water and electrolyte balances of five normal Standardbred geldings with a mean body weight of 427 kg, were determined over 14 day periods. The mean value of daily total water intake (a summation of free, combined and metabolic water intake) for the group was 27.6 litres, that is, 64.4 ml/kg body weight, while mean values for ambient temperature and humidity ranged from 16 to 25 degrees C and 55.4 to 75.5 per cent, respectively. The mean daily urine volume of 9.9 litres (23.2 ml/kg) for the group, was found to exceed the mean faecal water output of 7.2 litr...
Frape DL.There is no clear evidence that the chronic requirement for any non-energy yielding nutrient rises in proportion as the energy requirement increases with hard work. The need for protein, and probably that for calcium, remain a function of bodyweight daily. Some proportionality with energy may exist for certain nutrients, although the evidence has not been adduced. For example, because of an increase in both the proportion and amount of propionic acid in the volatile fatty acids of caecal contents, the tissue requirement for vitamin B12 may rise with an increase in the rate of energy metabolism...
Adams SB.Ileus may occur in horses of all ages secondarily to drug administration, colic, exhaustion, peritonitis, or metabolic disorders. Ileus most commonly occurs following abdominal surgery for colic and is a significant cause of postoperative mortality in these horses. The most common clinical signs of ileus are decreased or absent intestinal sounds and gastric reflux. Ileus is treated by eliminating the initiating causes, correcting metabolic imbalances, decompressing distended bowel, providing analgesia, stimulating motility with drugs, and regulating exercise and feed and water intake.
Smyth GB.Lengths of small intestine, caecum, ascending colon and descending colon were measured in intestinal tracts from 103 foetuses, foals and adult horses. Intestinal tracts from 21 of the horses were measured at varying intervals after death. Total intestinal length increased markedly from mid-gestation to one year of age, then showed little increment up to 35 years. Small intestinal length increased most rapidly in the first month of life. Caecal length increased most rapidly from one to six months and length of ascending colon increased most rapidly between one week and one year. Descending colo...
Stoianova LG, Abramova LA, Ladodo KS.The main biological parameters were studied in sublimated mare's milk: protein fraction composition, amino-acid spectrum, fatty-acid composition of lipids and the content of vitamins and mineral substances. A high biological value of the sublimated mare's milk has been proved, as well as significant proximity of its composition to human milk. Preliminary data have evidenced expediency of mare's milk use for the development of adapted milk mixtures for baby foods. However, the fatty component of the mixtures needs certain correction by addition of vegetable oil. The sublimated mare's milk can b...
Clarke LL, Ganjam VK, Fichtenbaum B, Hatfield D, Garner HE.The effect of feeding frequency and associated meal size on the renin-angiotensin-aldosterone system (RAAS) in seven horses was examined. A daily maintenance ration of hay-grain pellets was provided either as a multiple feeding regimen (MF), in which the ration was divided into six equal portions fed at 4-h intervals, or as a single large feeding (SF) given from 9 A.M. until 11 A.M. Plasma renin activity (PRA), aldosterone (PAC), cortisol (PCC), protein concentration (TP), packed cell volume (PCV), and serum sodium and potassium were measured serially. To prevent significant RAAS stimulation d...
Freeman DW, Potter GD, Schelling GT, Kreider JL.Nitrogen metabolism was measured in five mature geldings performing varying levels of work that simulated race training. Following an initial maintenance period without forced exercise, workload was increased in succeeding 18-d periods by doubling the distance the horses were galloped in each period from period 2 through 4. A 4-d N balance experiment was conducted at the end of each 18-d period. The maximum distance galloped daily, which was in period 4, was repeated in period 5. Then, workloads were decreased through period 7. Nitrogen balance was determined in two additional periods, 8 and 9...
Ross MW, Stephens PR, Reimer JM.A 9-year-old pregnant Standardbred broodmare was evaluated for signs of mild abdominal pain, failure to defecate, and mild abdominal distention. Rectal examination revealed the leading edge of a small colon intussusception, and peritoneal fluid analysis indicated suppurative peritonitis. Surgical management, including reduction of the intussusception and small colon resection with end-to-end anastomosis, resulted in successful outcome (1-year follow-up evaluation). Postoperative complications including dehiscence of the ventral midline surgical incision and simple obstruction at the anastomosi...
Oftedal OT, Jenness R.Milk samples of four species of wild equids (onager, Equus hemionus onager; mountain zebra, E. zebra hartmannae; plains zebra, E. burchelli; Przewalski horse, E. caballus przewalskii) and two domesticated equids (ass, E. asinus; pony, E. caballus) were analysed. At mid to late lactation the milks of all species were very similar, containing on average 10-12% total solids, 1-2% fat, 1.6-1.8% true protein, 6-7% 'lactose', 0.3-0.5% ash, 0.08-0.12% calcium, 0.04-0.07% phosphorus and a calculated energy content of 2.0-2.4 kJ/g. Milk samples collected in the first 2 weeks after birth showed elevated...
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...
Stull CL, Rodiek AV.Two experiments were conducted to determine the response of blood glucose, insulin and cortisol levels to four common equine diets. Experiment 1 was designed to determine the diurnal variation of glucose and two glucoregulatory hormones, insulin and cortisol, in four fasting geldings. No diurnal variation was observed in either glucose or insulin levels during the 24-h sampling period. However, cortisol levels did exhibit a circadian rhythm, with elevated values observed in the morning and low values in the evening. Experiment 2 investigated the response of glucose, insulin, cortisol and selec...
Hansen TO, White NA, Kemp DT.Total parenteral nutrition was accomplished in 4 healthy adult horses. During the 10-day study, the horses were not permitted to ingest food or water. Body weight was maintained at 94% of initial values without clinical evidence of dehydration. Serum urea nitrogen and triacylglycerol concentrations decreased during the study, without other significant hematologic or biochemical changes. Horses adapted without problems to the routine of IV feeding and confinement. All horses were healthy at the conclusion of the study. It was concluded that intravenous feeding with a lipid-glucose-amino acid-el...
Foster CV, Harris RC, Snow DH.1. L-carnitine was administered orally to thoroughbred horses for 58 days. 2. Acceptability and effects on plasma, muscle and urine concentration were studied. 3. Ten-60 g/day (as 2-3 doses) was acceptable with no deleterious effects. 4. One x 10 g L-carnitine significantly raised the plasma-free carnitine concentration (7 hr post) from 21.2 to 31.8 mumol/l; 2 x 30 g increased the mean to 36.5 mumol/l. 5. Plasma acetylcarnitine increased from approximately 1 to 5.5 mumol/l (7 hr post) on 2 x 30 g/day. 6. Muscle total carnitine was unchanged over 58 days. 7. Urinary output accounted for 3.5-7.5...
Ralston SL.A survey was taken of dietary management and training schedules of 54 horses competing in two 160 km endurance races. A total of 52 owners, representing 54 horses, responded to a questionnaire distributed prior to the races. Diet and training schedules were compared between horses that successfully completed the races and those that were eliminated for metabolic reasons. Horses that completed the races were 11.5 +/- 4 years old, weighed 429 +/- 4.5 kg and were ridden 61 +/- 32 km a week when training. Feed intake was reported as "free choice hay or pasture" by 34 of the respondents. Dry matter...
Schorr G.Serum iron concentration and iron-binding capacity were determined in 34 respectively 35 clinically healthy horses of different sex, with the age of 3 to 21 years. In the Warm blooded horse, the Half bred, the Haflinger horse, the Heavy horse and the Arabian Haflinger the mean serum iron concentration amounted to 253 +/- 66 micrograms/dl, 202 +/- 87 micrograms/dl, 166 +/- 67 micrograms/dl, 183 micrograms/dl and 366 micrograms/dl, while the iron-binding capacity in the Warm blooded horse, the Half bred, the Haflinger horse, the Thoroughbred, the Heavy horse and the Arabian Haflinger ran up to 4...
Houpt KA, Perry PJ, Hintz HF, Houpt TR.Twelve ponies were fed their total daily ration either as one large meal or divided into six small meals. Pre- and post-feeding behavior was recorded six times a day. Blood samples were taken for 30 min before and two hr after the meal. Plasma protein increased from 7.0 to a peak of 7.3 g/dl with small meals and from 7.3 to 8.1 g/dl with large meals, and returned to pre-feeding levels by 90 min post-feeding. Hematocrit rose from 33.3 to 34.1% with small meals and from 33.0 to 36.0% with large meals. These rapid and short-lived increases indicate a decrease in plasma volume. Plasma osmolality r...
Sweeney RW.Malassimilation should be suspected in horses with weight loss in spite of a good appetite. Malassimilation is usually confirmed with oral glucose or D-xylose absorption tests, whereas the oral lactose tolerance test can be used to evaluate lactase deficiency in foals. Once malassimilation is confirmed, other diagnostic tests such as abdominocentesis, rectal mucosal biopsy, or exploratory laparotomy with intestinal biopsies may determine the etiology of malassimilation.
Snow DH, Gash SP, Cornelius J.The effects of oral administration of high doses of ascorbic acid on plasma concentrations were investigated in both experimental Thoroughbred horses and those within racing stables. A single oral dose (20 g) did not result in any increase in plasma concentrations. However, daily administration of either 4.5 g or 20 g doses resulted in significant increases in plasma concentrations. Monthly variations in plasma ascorbate concentrations were found in both supplemented (20 g daily) and unsupplemented stables. It is concluded that oral supplementation with ascorbic acid is a satisfactory route to...
Shupe JL, Christofferson PV, Olson AE, Allred ES, Hurst RL.Teeth from cattle, sheep, and horses that ingested various fluoride intakes and teeth from field studies of these species plus deer, elk, and bison were examined for abnormalities. Approximately 99,000 animals in 322 herds were examined for fluorosis. From field studies, 988 cattle of various ages and with different degrees of dental fluorosis were slaughtered and necropsied. The severity of fluoride-induced mottling, hypoplasia, and abnormal abrasion of paired permanent incisor teeth was correlated with abrasion of premolar and molar (cheek) teeth that form and mineralize at approximately the...
McCann JS, Meacham TN, Fontenot JP.The digestibility and heat production values for three fats of different origin were determined. Four pony geldings (225 kg) were used in a study consisting of four successive digestion trials utilizing a 4 X 4 Latin square design. The four dietary treatments were basal alone and supplemented with 15% corn oil, blended fat or inedible tallow. The blended fat was composed of a mixture of animal and vegetable fats. A 7-d preliminary period preceded a 7-d total fecal collection period for each trial. Heat production values were obtained by indirect calorimetry and calculated from oxygen consumpti...
Harvey JW, Asquith RL, Sussman WA, Kivipelto J.Twenty-one healthy Thoroughbred and Quarter Horse foals were studied from birth until 1 year of age. Foals had access to an iron-supplemented creep feed before weaning and were fed an iron-supplemented concentrate as part of their diet after weaning at 4 months of age. Initial blood samples were taken before foals were allowed to nurse. Serum iron concentration, total iron-binding capacity, and PCV decreased during the foal's first 24 hours of life. Serum iron concentration decreased rapidly from 446 +/- 16 micrograms/dl (mean +/- SE) at birth to 105 +/- 11 micrograms/dl at 3 days of age. Seru...
Valieva TA, Valiev AG, Kulakova SN, Levachev MM.During six weeks rats were given a ration containing, as the only source of fat, lipids of sublimated mare's milk that had been stored with or without antioxidants (quercitrol, bisalcophen) during 3 months. The influence of specific quality of the ration fat on lipids and fatty acid composition of lipids in blood plasma, erythrocytic stroma and liver tissue, as well as on lipid peroxidation in the tissues was studied in the test animals. No changes induced by the lipids from sublimated mare's milk were detected in the parameters studied.
Beech J.This article discusses the history and signalment, clinical signs, differential diagnosis, pathology, etiology and pathogenesis, and treatment and prevention of equine degenerative myeloencephalopathy.
Foreman JH, Potter KA, Bayly WM, Liggitt HD.A 7-month-old male Quarter Horse was examined because of severe cachexia, which had begun 2 months earlier. The foal was emaciated and weak despite an excellent appetite. Percutaneous biopsy revealed multiple areas of subcutaneous steatitis with mineralization. Radiography demonstrated calcification of the nuchal ligament. The foal died 9 days after admission. Necropsy revealed mineralized lesions throughout the fascial planes and adipose tissues of the thorax, abdomen, and skeletal muscles, with little to no involvement of muscular tissue. Serum magnesium, copper, and thyroxine concentrations...
Whitlock RH.The equine practitioner often encounters serious diagnostic and therapeutic challenges regarding the specific origin of a disease. Such challenges may occur when horses become unaccountably ill after consuming what was thought to be acceptable feed but which in fact was contaminated or contained additives intended for other species. Examples of such additives and contaminants are monensin, lasalocid, salinomycin, blister beetles, and such antimicrobics as lincomycin and clindamycin.
Osweiler GD.Horses consume feed grains and forages that can produce a range of mycotoxins resulting from mold invasion. Toxicosis of horses often occurs from fumonisins or aflatoxin in grains, from the tremorgenic mycotoxins in dallis grass, or from slaframine in red clover. Fumonisin toxicosis often is severe and fatal, and aflatoxin can be acute or chronic and debilitating. Other mycotoxins reported in horses may cause moderate to mild signs that regress when the contaminated feedstuff is removed. Overall, horses appear to have a relatively low prevalence of reported mycotoxicoses among domestic animals...
Stammers JP, Leadon DP, Hull D.The fatty acid composition of the plasma free fatty acid, triacylglycerol and phospholipid fractions was measured in blood and milk samples taken daily from 3 mares and their foals on Days 1-9 post partum inclusive, and from a total of 12 mares and foals on Days 22, 30 and 51. A rise in the plasma concentrations of triacylglycerol and phospholipid similar to that well documented in other species occurred in the neonatal period. Alterations in the composition of the foal plasma phospholipid after birth lend support to the view that the placenta rather than the fetus could be responsible for the...
Irwin DH, Howell DW."Cube colic" is described and vain attempts to cause the problem on an experimental basis are recorded. It is concluded that not all horses are susceptible to cube colic and if colic occurs in horses being fed on cubes, it is not necessarily due to feeding of cubes. Nomenclature of bowel disorders is considered.
van Amstel SR, Reyers F, Colly PA.Variable results were obtained when the starch digestion test was carried out on a suspected case of malassimilation in a horse. In order to re-evaluate this test, 15 starch digestion tests were carried out using 4 horses. Results showed a marked variation in the increase in plasma glucose levels between individual horses and especially between poor and good condition horses when the dose of starch was based on body mass. Results also suggest that a fixed dose of starch may give more consistent results.