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.
Raisbeck MF, Dahl ER, Sanchez DA, Belden EL, O'Toole D.A review of Wyoming State Veterinary Laboratory records for 1947-1987 revealed no substantiated cases of naturally occurring selenosis. However, older reports attributed thousands of animal deaths to selenium each year in this area. Beginning in August 1988, cases of suspected selenosis and selenium deficiency were solicited from veterinarians and producers by announcements in various statewide livestock publications. As of August 1991, 4 cases (all horses) of naturally occurring selenosis have been confirmed. Clinical signs were most often referable to epithelial damage, e.g., hoof lesions an...
Pethick DW, Rose RJ, Bryden WL, Gooden JM.Nutrient uptake by the hindlimb was investigated utilising the arteriovenous difference technique in 5 Thoroughbred horses fed to maintenance a diet of 100% roughage or 52% oat grain and 48% roughage. Arterial blood was obtained from a catheter inserted into the carotid artery while venous blood was simultaneously collected from a catheter placed into the iliac vein via the medial saphenous vein. The arteriovenous difference for glucose was significant and represented a mean extraction of 10 +/- 1% with no effect of diet. If fully oxidised, glucose uptake (corrected for lactate and pyruvate ar...
Ross PF, Ledet AE, Owens DL, Rice LG, Nelson HA, Osweiler GD, Wilson TM.A study to evaluate the effects of dietary fumonisin B1 was conducted using 6 ponies (4 test and 2 control). A ration naturally contaminated with fumonisin B1 was fed in 3 phases: 1) 44 ppm fumonisin B1, 2) less than 1 ppm fumonisin B1, and 3) 88 ppm fumonisin B1. All ponies were monitored daily, weighed weekly, and limit fed at a rate of 0.8% body weight plus hay. Feed intake was measured daily, and a serum chemistry panel was completed once or twice weekly. Four to 7 days after initiation of the trial (Phase 1), all 4 test ponies had decreased feed consumption, and selected serum chemistry p...
Benamou AE, Harris RC.The changes in carnitine in plasma and milk during the first 3 months of lactation were studied in 14 broodmares and their foals. Six of the mares (Group S) were given a supplement of 10 g carnitine split between the morning and evening feeds, starting 2 weeks before birth. At birth the plasma carnitine concentration in Group S mares was about twice that in Group NS mares (no supplement). In both groups the concentration initially declined in the days after birth. Whilst this trend was reversed in Group S mares, the concentration in Group NS mares remained at a reduced level for the remainder ...
Engelking LR.It appears that different mechanisms responsible for fasting hyperbilirubinemia may be operative in different mammalian species (and subspecies). An increase in bilirubin production does not seem to occur in the horse, but a decrease in the hepatic uptake of bilirubin has been supported by a number of studies. Even though the delay in plasma elimination could also result from a decrease in hepatic blood flow, this possibility does not seem to play a major role since the hepatic uptake of compounds with low intrinsic hepatic clearance (e.g., ICG and bilirubin) appear to be affected more during ...
Stowe HD, Herdt TH.Assessment of the selenium status of livestock is an important aspect of production medicine, but variations in reported values between laboratories and between methods may be > 30%. Reliable interpretations require considerable experience with an assay and an extensive database from field and research case samples of a variety of species. The Michigan State University Animal Health Diagnostic Laboratory (MSU-ADHL) has offered Se analyses by acid-digestion and fluorometric detection since 1982. This laboratory expects serum Se values (nanograms per milliliter) of livestock to increase graduall...
Ullrey DE.Selenium was discovered 174 yr ago but, until 1957, was given little notice by biologists or was vilified as an agent that caused toxicity in grazing ruminants and horses in the northern Great Plains. After its status as an essential nutrient was established, Se received intense scrutiny, and hundreds of papers have been published dealing with its metabolic functions and the consequences of a Se deficiency. Because regions of Se deficiency are so extensive in the United States, great efforts have been made to gain Food and Drug Administration (FDA) approval for Se supplementation of animal die...
Buffa EA, Van Den Berg SS, Verstraete FJ, Swart NG.Over a 10-month period, 24 randomly selected riding horses were fed various amounts of biotin. Statistically significant improvements in growth rates and hardness of hooves were produced by biotin supplementation. Greater growth rates and hardness were achieved at a daily dose of 15 mg than at 7.5 mg. Increased hoof hardness was greatest in the hoof quarters and toe. No ring formation occurred in hooves of horses fed biotin intermittently.
Murray MJ, Schaudies RP, Cavey DM.Epidermal growth factor (EGF)-like activity was measured in mares' colostrum and milk by radioreceptor assay. Milk samples were collected from 22 mares 1 or more times during early lactation. Samples of colostrum were taken after parturition and before the foal first suckled (presuckle), within 6 hours after the foal first suckled (postsuckle), and on days 1, 2, 4, and 8 of lactation. In the 5 mares from which milk samples were obtained at each sampling time, presuckle colostral mean EGF-like activity (17.8 ng/ml) was greatest (P less than 0.05). The mean values for EGF-like activity at all ot...
Buffington CA, Knight DA, Kohn CW, Madigan JE, Scaman PA.The effects of 2 liquid formula diets differing in protein source were evaluated in orphan foals. The response of 7 foals fed a diet containing casein as the protein source, and 6 foals fed a diet containing a combination of whey and casein, was compared with the response in a reference group of 8 mare-raised foals. Orphaned foals were fed 150 kcal/kg of body weight/d, divided into 6 equal feedings of 25 kcal/kg. Formula intake was comparable among the experimental groups, and foals fed the liquid formula diet grew as well as mare-raised foals. There was no difference among groups in mean dail...
Ronen N, van Heerden J, van Amstel SR.Three cases of horses with nutritional secondary hyperparathyroidism (NSH) are described. The horses showed typical thickening of the maxillae and mandibular bones with or without lameness. Laboratory findings included elevated concentrations of parathyroid hormone (carboxy-terminal and mid-molecule fractions), alkaline phosphatase and an increase in the fractional excretion rate of serum inorganic phosphorus.
Furr MO, Crisman MV, Robertson J, Barta O, Swecker WS.Immune system dysfunction and immunoglobulin deficiency was diagnosed in a 2-year-old horse with disseminated lymphosarcoma. Prolonged (35 days) parenteral nutrition was delivered to support the horse during a period in which immune function studies could be performed. Correction of nutritional compromise by use of parenteral nutrition did not correct the immunoglobulin deficiency, and results of lymphocyte phenotype testing did not indicate abnormal proportions of leukocytes. Lymphoblast transformation studies were suggestive of a circulating immunosuppressive factor in the horse's serum. Nor...
Watson TD, Murphy D, Love S.The background, clinical signs, blood biochemistry and management of 18 cases of equine hyperlipaemia are described. Eleven of the animals were Shetland ponies, four were Welsh mountain ponies or their crosses, one was a fell pony and two were riding ponies of mixed breeding. Their average age was nine years. Fourteen of the cases were mares, of which nine were in foal and two were lactating; the remainder were geldings. Underlying or concurrent diseases were identified in only six animals, but in one other animal the hyperlipaemia appeared to have been precipitated by stress, and in another b...
Knottenbelt DC, Harrison LJ, Peacock PJ.Three foals under four weeks old and two under six months old with a history of oesophageal obstruction, had oesophageal strictures of different characters in the rostral cervical oesophagus. One case, which was complicated by severe inhalation pneumonia, was euthanased without any treatment and in another initial treatment by bougienage under general anaesthesia was attempted without success. The four surviving cases were provided with progressively firmer and coarser food, starting with liquid only, over a period of three to four weeks. The treatment is recommended in the early stages of str...
Martin RG, McMeniman NP, Dowsett KF.Intakes of milk and milk nutrients were determined for 8 foals at 11-18 days of age and for 10 foals at 30-44 days and 60-74 days of age while sucking grazing mares. Water intakes (sources other than milk) of the foals were determined at 30-44 days and 60-74 days of age. Five of the 10 mares were fed a protein supplement (24% crude protein) in addition to grazing during the stud season. The protein supplement did not influence foal intakes of milk and milk nutrients, milk composition, weight gains of the mares or the growth rate of the foals. Foal milk intakes increased (P less than 0.05) from...
McClure SR, Chaffin MK, Beaver BV.Self-mutilative behavior, a form of stereotypic behavior, can be a serious problem in stallion management. An 11-year-old Quarter Horse stallion was referred for evaluation of repeated episodes of self-mutilation and aggressive behavior. Historically, this behavior worsened when the horse was isolated from other animals and confined to a stall for long periods. Observations of the stallion revealed episodes of self-mutilation and other forms of stereotypic behavior precipitated by stressful situations. Modification of this behavior was achieved by environmental and nutritional management and p...
Clarke LL, Roberts MC, Grubb BR, Argenzio RA.In ponies fed concentrated (pelleted) meals, postprandial increases of plasma aldosterone have been temporally associated with a decrease in colonic fluid volume that parallels the conclusion of postfeeding fermentation. To determine the significance of short-term increases of plasma aldosterone on the rate of colonic Na absorption, in vitro transport studies were conducted on the mucosae of three morphologically distinct colonic segments (i.e., ventral, dorsal, and small colons) from ponies infused with a high physiological concentration of aldosterone for an 8-h period. In control ponies, ba...
Jaffé W.After a brief discussion of some of the aspects of importance, sources, deficiencies and excesses of selenium the great differences of ingestion between different countries are mentioned. Breast fed children from an area in Venezuela ingest 10 times the amount compared with children from Finland. Among sesame seed samples from 20 different countries used as Se indicators, the highest and the lowest values were found in those of Latin-American origin. With very few exceptions the highest and the lowest urinary and serum Se levels reported in the literature came from this region. The performance...
Podoll KL, Bernard JB, Ullrey DE, DeBar SR, Ku PK, Magee WT.Food and Drug Administration regulations currently permit addition of .3 mg of Se per kilogram of diet for chickens, turkeys, ducks, swine, sheep, and cattle. However, field reports indicate that this level may not be adequate for ruminants in all situations. Because sodium selenite is the most common supplemental form and is known to be readily absorbed to particles or reduced to insoluble elemental Se or selenides in acid, anaerobic environments, studies were conducted with dairy cattle, sheep, and horses fed sodium selenate to determine whether Se from this source was more bioavailable than...
Taira T, Fujinaga T, Tamura K, Izumi M, Itoh H, Tsunoda N, Yamashita K, Okumura M, Mizuno S.Equine alpha 1-acid glycoprotein (alpha 1AG) was isolated from equine serum by successive ammonium precipitation, anion- and cation-exchange chromatographies, and gel filtration. Purified equine alpha 1AG had a molecular weight of 46,000 +/- 1,000, and contained 31.4% carbohydrate. Gel isoelectric focusing revealed an isoelectric point range of 2.8 to 3.7. With immunoelectrophoresis, it was found that alpha 1AG migrated to the alpha 1-globulin region. Single radial immunodiffusion was used for quantitative measurement of alpha 1AG in equine serum. In clinically normal foals, serum alpha 1AG wa...
Freestone JF, Beadle R, Shoemaker K, Bessin RT, Wolfsheimer KJ, Church C.Ten hyperinsulinaemic ponies divided into conditioned (N = 5) and rested (N = 5) groups were evaluated for their insulin and glucose response following oral glucose administration at Weeks 0, 2, 4, and 6. All ponies received a controlled intake of a pelleted ration during the study. In both groups body weight had decreased from baseline by Week 4 and remained low. After 2 weeks of exercise, ponies in the conditioned group had significantly decreased insulin and glucose indices, including peak insulin response, area under the insulin curve from 0 to 210 min (TIS), and the TIS value: area under ...
Vandenbossche GM, Bouckaert S, De Muynck C, Mommens G, Van Zeveren A, Remon JP.The bioavailability and pharmacokinetics of ibuprofen, a nonsteroidal antiinflammatory drug, was studied in healthy Shetland ponies. Ibuprofen was administered IV, as a suspension, and as a solid solution oral paste to ponies from which food was withheld. The suspension paste was also administered to ponies that received hay and water ad libitum. Both formulations had an absolute bioavailability of about 80%. Bioavailability was not influenced by feeding.
Rice L, Ott EA, Beede DK, Wilcox CJ, Johnson EL, Lieb S, Borum P.Oral tolerance tests were performed on 13 neonatal foals to determine their ability to digest disaccharides on d 1, 3 and 5 postpartum. Foals were assigned randomly to treatments consisting of 20% (wt/vol) solutions of either maltose, lactose, or sucrose, dosed at 1 g/kg of BW, or glucose, dosed at .5 g/kg of BW. After a 2-h fast, an initial blood sample was collected via jugular catheter. Foals were administered the appropriate solution orally, and blood was collected every 15 min for 1 h and then every 30 min for 3 h. Plasma glucose increased after dosing with lactose or glucose but not with...
Golenz MR, Knight DA, Yvorchuk-St Jean KE.Nasogastric infusion of a human enteral feeding preparation was effective in reversing hyperlipemia in an anorectic miniature horse with an esophageal laceration. The nutrient preparation was delivered every 4 hours by gravity flow through a 12 F enteral feeding tube. Within 48 hours of initiating enteral nutrition, the hyperlipemia had resolved. Signs of intolerance to the preparation were not observed, and further weight loss was prevented. The use of a human enteral formula was a convenient and successful alternative for the treatment of hyperlipemia in the horse.
Doreau M, Boulot S, Bauchart D, Barlet JP, Martin-Rosset W.Voluntary food intake, milk yield and composition, and blood metabolites were measured during the first 2 mo of lactation in draft broodmares fed diets containing either 95% hay and 5% concentrates (Diet F) or 50% hay and 50% concentrates (Diet C). Voluntary food intake was higher for mares fed Diet C than for those fed Diet F (22.9 vs. 21.4 kg dry matter in wk 4). Both diets, especially Diet C, were eaten in amounts exceeding the energy requirements. Daily milk yield in wk 4 was 26.4 kg and 23.4 kg for mares fed Diets C and F, respectively. Milk fat and protein concentrations were higher (P l...
Ferrante PL, Menninger JH, Spencer PA, Kronfeld DS.Four mares fed a low fiber, high soluble carbohydrate diet were used in a crossover design to evaluate the effects of dietary sodium bicarbonate (NaHCO3) supplementation during daily low-intensity submaximal working conditions. Mares were fed the diet at 1.7 times the maintenance energy requirement for mature horses at work. The horses tolerated the diet well and had no clinical abnormalities. Resting venous blood bicarbonate (HCO3), standard HCO3, and base excess (BE) concentrations significantly (P less than 0.05) increased with NaHCO3 supplementation, but no significant changes in resting v...
Roberts MC.Lactase and cellobiase were detectable in the fetal intestine by the 3rd month of gestation, and although there was little change by the 9th month, maximal levels were reached at birth and steadily declined after 4 months. Conversely maltase, sucrase and trehalase were barely discernible in the fetus, maltase being present at low levels at birth, but all increased during the suckling period to attain adult levels by 7 months of age. Alkaline phosphatase activity matured earlier than did disaccharidase activity. Mucosal enzymes other than alkaline phosphatase were virtually absent from meconium...
Schryver HF.Recent knowledge regarding the absorption of calcium and phosphorus from the intestine of the horse has been reviewed. Consideration has been given to sites, mechanisms and factors affecting absorption as well as to the availability of calcium and phosphorus from feedstuffs commonly used in Eastern North America. Although the anatomy of the digestive tract might appear to impose restrictions on the ability of the horse to assimilate minerals, studies of absorption show that the horse utilizes the calcium and phosphorus of many feeds very efficiently.
McManamny LF.This research argues for the veterinarians leading the planning and enforcement of disease control measures in thoroughbred stud farms, emphasizing their expertise and knowledge in disease diagnosis and management. Collaboration […]
Step DL, Divers TJ, Cooper B, Kallfelz FA, Karcher LF, Rebhun WC.A 6-year-old Quarter Horse was examined because of acute, severely swollen masseter muscles (palpation of which elicited pain response), exophthalmos, severe chemosis, and protrusion of the third eyelids. Blood selenium and vitamin E concentrations, and results of feed analysis and muscle biopsy supported a diagnosis of nutritional myopathy. The horse was treated and was clinically normal 2 weeks after discharge from the hospital.