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.
Baker H, Schor SM, Murphy BD, DeAngelis B, Feingold S, Frank O.Blood concentrations of thiamin, biotin, nicotinates, pantothenates, folates, riboflavin, vitamins A, B6, B12, C, E, beta-carotene and choline were analyzed in healthy animals (23 horses, 25 dogs, and 29 cats). B-Complex vitamins and choline also were analyzed in the liver of the dogs and cats. Vitamin concentrations in the blood and livers of dogs were similar; however, blood vitamin A and beta-carotene concentrations were lower in the cat than in the dog. Horses had a higher B12 blood concentration than did the dogs and cats. These data can be useful for detecting overt and hidden vitamin de...
LeBlanc MM, McLaurin BI, Boswell R.Postpartum, presuckle, colostrum samples were collected from 100 mares. Colostral specific gravities significantly correlated (r = 0.9) with colostral immunoglobulin (Ig)G concentrations. Foal serum IgG concentrations highly correlated (r = 0.82) with specific gravities of the colostrum each foal ingested. Eight of 48 foals (17%) had serum IgG concentrations less than 400 mg/dl. The dams of these 8 foals had colostral sp gr less than 1.06 and colostral IgG concentrations less than 3,000 mg/dl. Foals had serum IgG concentrations greater than 520 mg/dl 24 hours after parturition, when the colost...
Cymbaluk NF, Christensen DA.Five groups of horses were fed different diets of known trace mineral concentration for a minimum of six months. Copper (Cu), zinc (Zn) and manganese (Mn) concentrations were measured in livers of 125 yearling horses and kidneys of 81 yearling horses as an assessment of trace mineral status. Plasma Cu and Zn determinations were made for all horses.Mean hepatic Cu concentrations of horses fed diets containing 6.9 to 15.2 mg Cu/kg dry matter (DM) feed were 0.27 to 0.33 mumol/g DM tissue. Plasma Cu concentrations ranged between 22.8 to 28.3 mumol/L. There was no simple mathematical relationship b...
Pagan JD, Hintz HF.Twenty-two pony mares were fed one of three diets that provided 93.0, 74.8 or 57.2 kcal of digestible energy (DE) per kg body weight per day. Milk samples were taken at 14 day intervals. A total of five samples were taken from each mare. The samples were analyzed for total solids, crude protein, lactose, total lipids, ash, calcium and phosphorus. Gross energy was calculated from composition data. Increases in energy intake decreased the concentration of total solids, protein, fat and gross energy of mare's milk. Energy intake had a greater influence on the mare's body condition than on milk en...
Robb EJ, Kronfeld DS.A 3-year-old mare repeatedly had clinical signs of rhabdomyolysis on mild exertion. Serum creatine kinase and aspartate transaminase activities were high at rest. Responses to dietary sodium bicarbonate were tested through 7 alternating periods of supplementation of a basal ration of timothy hay and oats. Physical signs; venous blood pH and gases; blood glucose and lactate; serum electrolytes, enzymes, and creatinine; and urine pH were monitored before and after exercise. Dietary sodium bicarbonate raised resting venous blood pH and bicarbonate slightly and significantly increased urine pH fro...
Ruoff WW, Baker DC, Morgan SJ, Abbitt B.DIABETES mellitus is an uncommon disease in the horse and,
when reported, is frequently secondary to Cushing’s disease
(King, Kavanaugh and Bentinck-Smith 1%2; Loeb, Capen
and Johnson 1966; Tasker, Whiteman and Martin 1966;
Baker and Ritchie 1974; Pauli, Rossi and Straub 1974; Moore,
Steiss, Nicholson and Orth 1979). Diabetes mellitus, associated with chronic pancreatitis, was reported in a horse with
hyperglycaemia, glycosuria and ketonuria (Jeffrey 1969).
Other reported cases were not examined fully to determine the
underlying cause of hyperglycaemia (Jorgenson 1921 ; Wilkinson 195...
Garcia MC, Beech J.Intravenous glucose tolerance testing (0.5 g/kg of body weight) was done on 2 groups of healthy horses maintained with hay (group 1, n = 5) and with hay plus grain supplementation (group 2, n = 5) and on a group of horses with clinically diagnosed pituitary adenoma (group 3, n = 10). Healthy horses showed an immediate increase of plasma glucose concentration after the IV glucose injection, with return of values to base line in 1 hour. Group 3 horses showed resting hyperglycemia and a delayed return of glucose values to base line (3 hours). Group 3 horses showed resting hyperinsulinemia and a f...
Smith JE, Cipriano JE, DeBowes R, Moore K.Values for serum ferritin, serum iron, and serum total-iron binding capacity were determined in 100 hospitalized horses. Six foals had iron deficiency, as indicated by low serum ferritin and iron concentrations. Twenty-eight horses had low serum iron content and normal or high serum ferritin content and were considered to have pseudo-iron deficiency, possibly in response to infection. Ten horses had serum ferritin concentrations that were quite high, probably indicating iron overload.
Ott EA, Asquith RL.Three experiments using 63 Thoroughbred and Quarter Horse yearlings were conducted to evaluate the influence of level of feeding, and protein and calculated energy content of pelleted concentrates on growth and bone development. Animals were housed in drylot paddocks and individually fed concentrates twice daily. Coastal bermudagrass (Cynodon dyctylon) hay was group-fed. Yearlings offered a corn-based concentrate (3.56 Mcal digestible energy [DE]/kg) consumed levels of dry matter similar to yearlings fed a mixed-grain concentrate (3.32 Mcal DE/kg but consumed slightly more digestible energy. N...
Kalinskiĭ MI, Kamenetskaia OV, Skorik LG, Tishchenko GN.The paper deals with possibility to regulate in a proper direction the acid-base state in race horse blood administering carbostimulin at rest and under physical exercises. The preparation is shown to favour an increase in alkaline blood reserves in race hours at rest and to prevent acidotic changes caused by physical exercises. The results obtained show a promising use of carbostimulin for the directed correction of the acid-base state of blood in race horses aimed at increasing the efficiency of the training process.
Wintzer HJ.A long-term treatment with biotin (vitamin H) in 5 warm-blooded horses and 10 trotter horses is reported. The dose of 0.031-0.037 mg/kg body weight was well tolerated, and with a therapy period up to 10 months an improvement of the horn quality of the growing hoof could be attained as it had not been possible before with other measures. Biotin (Gabiotan) is recommendable as a therapeutic in all cases of hoof problems which are based on disturbed horn elasticity.
Schryver HF, Oftedal OT, Williams J, Cymbaluk NF, Antczak D, Hintz HF.Milk samples were obtained in early and/or late lactation from Przewalski horses, Hartmann's zebras, Grant's zebras, domestic horses, ponies and a mule mare made pregnant by embryo transfer. Samples were compared for their content of total solids, ash, calcium, phosphorus, magnesium, sodium, potassium, copper, zinc and iron. Milk from the Przewalski horses, Hartmann's zebra and the domestic horse had similar mineral composition and the content of minerals was higher in early than in late lactation. Milk from the domestic mule contained the lowest concentration of calcium, phosphorus and zinc b...
Doreau M, Boulot S, Martin-Rosset W, Robelin J.The milk and nutrient intakes of 21 nursing foals of heavy breeds (adult weight: 800 kg) were determined at 1, 4 and 8 weeks of age. Lactose intake increased (P is less than 0.01) from 1 300 g/day at 1 week of age to 1 800 g/d at 8 weeks; fat decreased (P is less than 0.01) from 400 g/d to 300 g/d and protein did not vary (600 g/d). Energy and nitrogen intakes did not depend on the source of energy in the mother's diet. Milk, energy and nitrogen intakes were well related (r = 0.74 to 0.81) with foal growth between 1 and 4 weeks, but not between 4 and 8 weeks. The composition of weight gain sho...
Todhunter RJ, Stick JA, Slocombe RF.The effects of 3 feeding techniques on healing of a cervical esophageal mucosal resection and anastomosis were investigated in 16 horses. Horses were fed a moistened pelleted diet 1 of 3 ways: 1) per os (n = 5), 2) by nasogastric (n = 5) or 3) by esophagostomy tube (n = 6) until the 14th postoperative day. The pelleted diet was then fed orally in all horses until euthanasia on the 60th postoperative day. Immediate postoperative feeding per os was unsatisfactory, as only 2 of 5 horses survived in this group. Endoscopic evaluation revealed that mucosal dehiscence of varying degrees occurred, wit...
Ronéus BO, Hakkarainen RV, Lindholm CA, Työppönen JT.Vitamin E requirements of adult Standardbred horses were evaluated by tissue depletion and repletion. All the horses used in the study were given the same basal feed low in vitamin E during the eight months of the experiment. After an initial depletion period of two-and-a-half months the horses were divided into groups according to the amounts of DL alpha-tocopheryl acetate given (0 mg, control; 200, 600, 1800 and 5400 mg, respectively) as a daily oral supplement. The supplement study was followed by a second depletion period. Total vitamin E content and individual natural tocopherol isomers a...
Maczulak AE, Dawson KA, Baker JP.A total of 114 bacterial isolates were obtained from the cecal contents of two mature cecally fistulated horses on a habitat-simulating medium containing 40% energy-depleted cecal fluid. Of these isolates, 108 were maintained in pure cultures and were tentatively grouped on the basis of cell morphology and physiological characteristics. Gram-negative rods (50.9%), gram-positive rods (22.8%), and gram-positive cocci (21.9%) represented the largest groups isolated from these animals. Fifty isolates were tested for their ability to grow in media containing urea, ammonia, peptones, or amino acids ...
Piscator M.Cadmium exposure, metabolism, and effects are described especially in relation to dietary intakes. Data on dietary intakes in several countries have been complied from studies using the duplicate diet method or fecal analysis. These two methods seem to give more accurate data than estimates based on cadmium concentrations in food classes and food consumption (composite method). The present data on absorption and retention of ingested cadmium indicate that normally less than 5% is ingested, but absorption may increase in women who have iron deficiency. Earlier estimates of the critical concentr...
Morris DD, Meirs DA, Merryman GS.A prospective study was performed to determine the incidence and associated maternal and managemental factors of failure of passive transfer (FPT) in foals on a breeding farm. The zinc sulfate turbidity test (ZSTT) and latex agglutination test (LAT) were compared for accuracy in estimating serum immunoglobulin (Ig)G of foals, as determined by single radial immunodiffusion (SRID). Complete past and present foaling histories of 136 Standardbred mares were obtained. All foalings were witnessed by farm attendants, and colostral samples were collected from mares within 2 hours after parturition. Fo...
Youket RJ, Carnevale JM, Houpt KA, Houpt TR.The effect of meal frequency on body fluid, glucose, triiodothyronine (T3), heart rate and behavior was measured in 10 ponies. A simple reversal design was used in which each pony received one meal/day (1X) for 2 wk and six meals/day (6X) for 2 wk. The total intake/day was held constant. Feeding was followed by a rise in plasma levels of glucose, T3, protein and osmolality. One large meal was followed by significantly greater changes in all of the variables than was a meal one-sixth the size. Plasma T3 rose from 41 +/- 5 (SE) ng/liter before feeding to 43 +/- 5 ng/liter following a small meal,...
Engelking LR, Anwer MS, Lofstedt J.Fasting is associated with unconjugated hyperbilirubinemia in several species, including the horse. Studies in ponies showed that a 3-day fast decreased plasma clearance of bilirubin, cholic acid, and sulfobromophthalein (BSP). Since these organic anions are conjugated with different substrates, it is possible that observed differences in plasma clearance result from a general decrease in hepatic conjugating capacity during the animals' fasting. To test this hypothesis, the effects of a 3-day fast on plasma clearance of IV injected BSP (4.4 to 5.1 mg/kg), which is conjugated to glutathione, an...
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...
Martens RJ, Malone PS, Brust DM.Oral lactose tolerance tests were evaluated in 25 healthy foals (principals) assigned to 4 groups of approximately 1 week, 4 weeks, 8 weeks, and 12 weeks of age. Lactose monohydrate (1 g/kg of body weight [in a 20% water solution]) was administered via nasogastric tube after a 4-hour fast. Plasma glucose concentrations were monitored before dosing (0 minutes) and sequentially for 300 minutes. Six control foals were given a volume of water equivalent to the volume of lactose monohydrate administered to principal foals. After oral lactose loading, mean plasma glucose concentrations of all princi...
Orton RK, Hume ID, Leng RA.Rates of growth were measured in two-year-old (Experiment 1) and nine-month-old (Experiment 2) horses fed high (12 or 14 per cent) or low (6 or 8 per cent) crude protein diets with one of two levels of exercise (0 or 12 km trotting per day at 12 km/h). In the non-exercised horses feed intakes and growth rates were greater on the high than on the low protein diets. Exercise increased feed intakes and growth rates of horses on the low but not the high protein diets, so that in the exercised groups there were no significant differences in feed intakes or growth rates between the horses on the two...
Lezica FP, Filip R, Gorzalczany S, Ferraro G, de Erausquin GA, Rivas C, Ladaga GJ.In the present study, we determined the incidence and effects of season and weather on clinical manifestations of endophyte-infected ryegrass toxicity, performed chemical detection and pharmacological bioassays on ryegrass extracts, and conducted trials on: (i) effects of domperidone or metochlopramide on ovarian inactivity induced by endophyte-infected ryegrass; (ii) efficacy of buspirone or dihydrochloro phenyl piperazine (m-CPP) for preventing suppressed milk production induced by endophyte-infected ryegrass; and (iii) efficacy of domperidone to induce ovulation during winter anestrus. Mare...
Belonje PC, van Niekerk CH.Attention is drawn to the beneficial effect of improved nutrition during winter and early spring on the ovarian activity of mares. Furthermore, the necessity of an adequate plane of nutrition during early pregnancy to prevent embryonic resorption is stressed.