Warm Temps & Water Consumption

The transition in temperature and humidity from cool season to warm season may require an adjustment in watering horses. Reduced water consumption may impair performance and may increase the risk of impaction colic. Also, horses that are not conditioned properly may sweat more profusely than a well-conditioned horse, and thus dehydrate faster. This is particularly important early in the season when temperatures may change suddenly and horses may not yet be in peak condition.

The first key element is to make certain that horses have ready access to clean, palatable, cool water at all times or at very frequent intervals. Horses will normally consume about 1 gallon of water per 100 lbs body weight, so an 1100 lb horse will require a minimum of 11 gallons of water per day. This quantity can increase substantially during periods of exercise, high heat/humidity or for lactating mares.

Some tips to keep in mind to keep water consumption up:

  • Horses do not like to consume warm water in warm temperatures. Automatic waterers or large tanks, located in the shade and cleaned regularly, may be good options. If water is supplied in buckets, they need to be cleaned regularly and re-filled regularly.
  • If you are traveling to a show or other competition, it is essential to monitor water consumption, particularly if temperature conditions change.
  • It is routine in many barns to flavor the water with something like wintergreen or peppermint at home so that you can flavor the water in new facilities to match the home water.  Read here for tips on training your horse to drink water away from home.
  • Do NOT use soft drinks or any material containing caffeine as these can trigger positive drug tests.
  • Taking horses to facilities with chlorinated water can sometimes reduce water consumption without proper precautions.

The second key element is to make certain that salt is offered free choice. Things to keep in mind for salt consumption in horses include:

  • Horses require 1-2 ounces of salt per day, and this can increase to 6 ounces per day with exercise in hot weather conditions.
  • Loose salt is consumed more readily than salt blocks in many cases.
  • When evaluating the total diet for salt consumption, commercial feeds normally contain 0.5-1.0% salt. It is not typically any higher than this, due to problems with palatability.
  • If a horse has been salt deficient or is bored, they may over-consume salt while in a stall.
  • Additional electrolytes, commercial or personal recipe, may be used per directions before, during and following completion, but care must be taken to ensure that the horses are drinking adequate water. Administering electrolytes to a horse that is not drinking properly, or allowing a horse to over consume salt without adequate water, can lead to electrolyte imbalances. If electrolytes are added to the water, plain water should be offered also.

Horses need to be offered water throughout the day at a competition, and should be re-hydrated following exertion. They cannot cool out and recover properly without being re-hydrated. Keeping horses properly hydrated and maintaining electrolyte balance is extremely important in order to make a safe transition from cool temperatures to summer time and competition.

Types of Minerals Used in Horse Feeds

In the case of minerals found in a bag of commercially prepared feed, the form of mineral used as an ingredient can be looked at.  There are a variety of types of minerals that can be used as ingredients, with varying levels of bioavailability, or ability to be absorbed by the animal, for each of them. 

  1. Inorganic trace minerals, namely oxides and sulfates, are the most common, with oxides having about half the bioavailability of sulfates, except in the case of copper and zinc.  These would be seen on a feed tag as “zinc oxide” or “copper sulfate”. 
  2. Organic* trace minerals, namely “chelates” and “complexes”, are two forms of minerals that are gaining popularity in horse feeds due to their increased digestibility. 
    1. Chelates are a mineral molecule tied to a string of general amino acids. These are seen on feed tags as “zinc amino acide chelate”.
    2. Complexes (the more bioavailable of the two) are minerals tied to a specific amino acid that is known to assist in the availability.  These are seen on feed tags as “zinc methionine complex”. 

Premium horse feeds often contain one of the two forms of organic trace minerals, as they are the more bioavailable forms. They are generally used in combination with the inorganic forms to acheive the desired level, without skyrocketing the price of the feed.

For more information on trace minerals in horse feed, visit ZinPro’s website - ZinPro is a key supplier of trace minerals in the feed industry.

*Please note that “organic” is not referencing certified organic products like you would purchase at a grocery store – instead it is a scientific reference to the chemical makeup of the mineral.

Minerals in Horse Feeds

There are a variety of minerals that are important in horse nutrition.  As we learned in previous blog posts, it is important not to put too great of an emphasis on any one particular mineral, although some do require greater supplementation than others.  For example, rarely will iron or iodine be seen listed in the guaranteed analysis on a horse feed tag, but most all commercially prepared feeds will have guaranteed levels of copper and zinc.  The reason for this is that some nutrients are naturally present in most forages, but others are often not present in high enough levels to fulfill the needs of today’s horse – a horse with the demands of performance placed on it. 

Also, it is important to note that when looking at a feed tag, just because a particular mineral is not listed on the guaranteed analysis, that does not mean that it is not present in the feed.  Many minerals are naturally occurring in the ingredients used to produce the feed, and in some cases does not need to be supplemented on top of the other ingredients.

Below is a quick guide to some of the basic minerals and what their function is in the horse:

Magnesium is necessary to reduce stress and irritability. Although rare, deficiency may occur in horses on high grain diets or animals in high-stress situations. If deficient, horses are high-strung, and jumpy. Rations with significant forage generally have no problem with magnesium deficiency.  Grass tetany as seen in cattle is not an issue in horses, as horses absorb magnesium much more efficiently than cattle do.  Toxicities are not generally seen in horses.

Potassium has a major function in muscle activity, and acid-base balance. It may be deficient in horses on high-grain diets. Deficiency symptoms may be reduced intakes, muscle weakness, diarrhea, and a slow-down in growth. Forage is important to prevent potassium deficiency. Toxicity is not generally an issue if adequate water is provided, as excesses are excreted in the urine.

  • Potassium has gained most of its notoriety with the onset of HYPP in the quarter horse world. Feeding elevated levels of potassium can induce an attack in an HYPP-positive horse. Total dietary potassium in a HYPP-positive horse should be kept to less than 1%.

Cobalt is necessary for synthesis of vitamin B12 in the intestinal tract. However, the requirement is very low.

Copper is necessary for hemoglobin formation, along with iron and vitamin B12. Anemia and abnormal bone development in foals may be symptoms of deficiency. Often deficiencies occur in suckling foals, as the mare’s milk has very low levels of copper.  Care should be taken with pregnant mares to feed a diet sufficient in copper during the last 3-4 months of gestation, when the unborn foal is laying down stores of copper in it’s liver to get through the nursing period without problems. Copper levels are also of great interest in developmental orthopedic diseases.  Toxicity is very rare in horses, and deficiencies in mature horses are also not seen often.

Iodine is needed to make thyroxin, which controls the ratio of body metabolism. When iodine is deficient, foals may be born dead. Mares may be unable to nurse or have higher than normal naval ill when iodine is deficient.  Both toxicity and deficiency lead to hyperthyroidism, due to the fact that a toxicity impairs/inhibits release of thyroid hormones, while a deficiency doesn’t allow for sufficient hormone production.

Iron is necessary for the formation of hemoglobin, which enables the blood to carry oxygen. Iron deficiency anemia is a deficiency symptom. Horses under the heavy stress of racing or showing may develop deficiency symptoms, as well as horses with chronic blood loss from parasite damage.  Symptoms of toxicity can include depression, diarrhea, or increased susceptibility to bacterial infections.

Manganese is essential for bone formation, growth and reproduction. Manganese deficiency symptoms may be poor growth, lameness or bowing of legs, as well as reproductive dysfunction. Most feedstuffs are rich in manganese. 

Selenium is associated with white muscle disease and the death of foals. Deficient animals have muscle disorders, such as tying-up. However, greater than 5 ppm selenium in the ration may be toxic to the horse.  Feed companies are not allowed to supplement selenium at a rate that would give more than 0.3 ppm in the total daily intake when fed as directed.  Should be fed with Vitamin E, as they work together in the body.

Zinc gives gloss or “bloom” to hair coat and is needed for protein synthesis and metabolism.  Needs to be kept in ratio with copper, with the ideal ratio being between 1:3 and 1:4 copper to zinc.  Zinc is also being heavily looked at in relation to the occurrence of developmental orthopedic diseases.

Measuring Minerals in Horse Diets

Minerals are generally listed in two ways on a feed tag guaranteed analysis. 

  1. Macro minerals, or those needed in larger quantities, are expressed as a percentage. They include calcium, phosphorus, sodium, chlorine, potassium, magnesium, and sulfur. 
  2. Micro minerals, or those needed in smaller amounts, are expressed as “parts per million” which is what the “ppm” on the tag stands for.  Occasionally a feed tag will list these in “mg/kg”, which converts directly to ppm – 1 ppm is equal to 1 mg/kg.  These minerals include selenium, iodine, copper, zinc, manganese, and iron.

When analyzing a feeding program, it is of great importance to make sure that the same units of measurement are being used.  Often times, test results for a hay sample that has been analyzed will not be expressed in the same unit of measure as the nutrients guaranteed on a bag of feed.  So, in order to know what the entire diet is providing, make sure you are comparing apples to apples!