Tuesday, 04 December 2012 09:29


Written by  Dr. Bob Wright
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Many livestock owners expressed concern with the drought of 2012. Unfortunately, most of North America was in a similar situation. By early August, hay and grain prices sky-rocketed to record prices. The harvest of first cutting hay in many areas was good, but second cutting was non-existent. Farmers harvested what second crop hay was available with hopes that a third cutting harvest would be brought on by rain in early August. Regardless, hay inventories across North America are low. There are some key strategies that will help you through the dry times. Unfortunately, it is too late for this year to implement some of them. (Note: All references to nutritional quality will be on a 100% dry matter basis (DM) as obtained from either the 5th or 6th Edition of Nutrient Requirements for Horses. Refer to my web site wwww.horsenewsandviews.com for further reading where indicated below.)

Horses need a good source of forage daily. Forage in the form of hay and pasture are the traditional cornerstones of horse rations. At least 50% of a horse’s daily feed intake (1.25 to 1.5% of body weight) should consist of good quality forage. For the average adult light horse weighing 500 kg (1,100 lb.), this equates to a minimum of 7.5 kg (15 lb.) of dry hay. Forages are an important source of digestible energy (DE), protein (CP), minerals (e.g., calcium (Ca), phosphorus (P)), vitamins, and fibre. Long-stem hay and pasture grasses contain over 20% crude fibre (CF) or expressed as 50 to 60% NDF (neutral detergent fibre). The higher the NDF is, the higher the fibre content. Most grain mixes, even so-called “complete” feeds, contain less than 12% CF (<12% NDF). Horses can adapt to balanced rations that do not contain hay or pasture, but the absolute minimum of fibre necessary has not been established. Low fibre/high concentrate rations have been documented to increase the risk of colic and gastric ulcers and will dramatically increase a horse’s desire to chew wood.

Strategy 1: Preserve what you have/ Pasture management
Pastures are often poorly managed by horse owners. Good pasture managements start with;
• Maintaining high fertility in the soil through prudent use of chemical fertilizers. Fertilizer should be applied early in the spring and at strategic periods in summer and fall. High fertility will decrease drought stress on plants. Seek the advice of local fertilizer dealers.
• Preventing horses from over grazing and damaging pastures. It is too late for this season. However, subdivide your pasture(s) with electric fence to create areas that will be grazed short for five to seven days and then move the horses to a new section allowing each section a minimum three-week rest period.
• Ensuring that poisonous plants don’t get a foothold in pastures. Poor pasture management leads to the influx of weeds. In drought periods, horses will eat anything that is thought to be palatable, including poisonous plants (e.g., bracken fern, horse tail etc.) and leaves (e.g., red maple) with disastrous results. (Refer to factsheet; Managing Horse Pastures; Hay for Horses; Toxicity of Equisetum to Horses; Bracken Fern Poisoning.)
• Feeding – Place hay in a feeder with a pan or bottom that catches the leaves. Don’t feed on the ground. In the 1980s, Les Burwash and Bob Coleman of Alberta Agriculture, showed that horses fed hay in a simple four-foot-by-four-foot plywood box with a bottom reduced waste and increased the growth of weanling horses by 25%. If hay is $8 a bale, every time you place it on the bare ground you are wasting $2 of hay. Well-built hay feeders can be safe and quickly pay for themselves. (Refer to factsheets; Using and Feeding Round Bales to Horses, Round Bale Feeder for Horses.)

Strategy 2: Use Alternatives to extend Long-Stem Dry Hay
Livestock such as sheep, goats and cattle are fed a variety of crops to meet their nutritional needs. Some of these can be used to replace hay but most are hay extenders. They include preserved forage (e.g., hay crop silage [haylage], corn silage, straw and root crops (e.g., carrots and turnips).

2.1 Haylage, Grass Silage and Corn Silage
Haylage is produced by the ensiling process, which consists of cutting, partially wilting and placing young respiring plants in a silo or container, such as a plastic bag, where the air is eliminated. Ensiling maintains the quality of the forage as it was cut. It is usually high in energy, protein and fibre because the cutting date is not dependent on the weather. The high moisture level and lack of dust are useful when feeding a horse with heaves. Haylage feeding brings the danger of botulism. Serotypes A and B neurotoxins are associated with wet or spoiled forages. Horses should be vaccinated for botulism prior to being fed haylage or corn silage. However, a vaccine is available only for Serotype B. (Refer to the information sheet; Hay, Haylage and Treated Hay for Horses.)

Corn silage, like haylage, is fermented high moisture forage. It is made by chopping the whole corn plant, placing it in a bag or silo which excludes oxygen and allowing the content to ferment. It is high in fibre (CF 25% or NDF 49%), moderate energy (DE 2 Mcal/kg) and low in protein (CP 8.9%). It has been fed to horses, but should only be fed by those who are knowledgeable about what spoiled silage looks and smells like. It, too, carries the danger of an increased incidence of botulism.

2.2 Acid Treated Hay
Acid preservatives are applied to hay during wet haying seasons or with late season harvests where it is hard to get hay to dry with the shorter days and heavier dews. The preservatives are of various types, e.g., proprionic acid and are applied to the hay during the baling process. The preservatives, when used properly, allow the storage of hay at a higher moisture content level than dry hay. Only proprionic acid preservatives have been studied for feeding to horses. Horses prefer non-preservative-treated hay when given a choice, but will consume equal quantities of either when not given a choice. Proprionic acid is normally produced in the gastrointestinal system of horses.

2.3 “Complete” Concentrates
“Complete” concentrates are mixtures of grains, hay or beet pulp, vitamins and a mineral supplement. They are available in textured, pelleted or extruded forms and designed to be fed without hay, grain or other supplements and still meet the horse’s basic needs. “Complete” concentrates are available in a wide variety of nutritional profiles. Ensure that you purchase the one to suite your horse’s requirements (e.g. an adult horse for maintenance vs. a growing or performance horse). The label should contain the statement “designed to be fed without forage.” (Do not confuse complete concentrates with concentrates that are mixtures of grains designed solely for feeding with hay or other forages.) Unfortunately, complete concentrate products lack sufficient fibre to satisfy the horse’s need to chew. Fibre deficiency will cause dramatic increases in wood-chewing activity.

Use complete concentrate feed instead of, not in addition to, a horse’s regular grain ration. Switch horses to the complete concentrate rations slowly, taking over a week to completely eliminate hay from their diet and get them on the amounts of complete concentrate feed necessary to meet their needs. Feeding smaller amounts (1 to 1.5 kg or 2 to 3 lb. per feeding) more frequently will not only optimize digestion but will also keep the horse better occupied. Feeding horses complete concentrate feed without any other source of roughage may increase the risk of colic and/or laminitis.

2.4 Hay Cubes
Long-stem hay, either alfalfa or a mixture of alfalfa and timothy hay, is dried, chopped and compressed into cubes. The nutritional quality is dependent on the hay used to make the cubes. When hay is in short supply and expensive, hay cubes will equally be in short supply and expensive. Hay cubes can be fed up to 5.4 to 6.8 kg (12 to 15 lb.) of cubes per 1,000 lb. horse per day. A dramatic increase in the incidence of wood chewing is observed when feeding hay cubes. The incidence of choke is also increased. The danger of choking is eliminated by soaking the cubes in water for 10 minutes before feeding them to the horse.

Straight alfalfa cubes will contain high protein and calcium concentrations along with a high Ca:P ratio. These nutrients are supplied at concentrations higher than the normal adult horse requires, but will not harm the horse as long as its kidneys are functioning properly. Alfalfa cubes are more appropriate for either lactating mares or growing horses and as a partial forage substitute. While up to 6.8 kg (15 lb.) or more can be fed per horse per day, 1 to 2.5 kg (2 to 6 lb.) of cubes per horse per day can be used as a “hay extender” if only poor-quality hay is available in limited quantities.

2.5 Straw
Straw is left over stalks from harvesting grain crops (wheat, barley and oats). It contains very little nutritional value (DE 1.62 Mcal/kg, CP  3.5%). It is a great source of fibre (CF 41% or NDF 78%). If the horse’s energy, protein, mineral and vitamin needs are met by feeding a complete pelleted, extruded or textured concentrate, bedding the horse on straw will satisfy the horse’s desire to chew and reduce the amount of wood-chewing activity. Think of straw not as a source of nutrition for horses, but rather as a “chew factor” and fibre source. However, straw can cause impaction colic.

Straw may be contaminated with mycotoxins produced by different fungi especially in years of wet weather. This is less likely this year, but be cautious about the intentional or unintentional feeding of potentially Fusarium-infected straw. Rye straw can be infected with the fungus, Claviceps species. It will cause dystocia (difficulty foaling) in pregnant mares. Do not use rye straw with pregnant mares in the last two months of gestation. (Refer to; Molds, Mycotoxins and their Effect on Horses.)

2.6 Beet Pulp
Beet pulp is a by-product of the sugar beet industry. It is a good source of fermentable fibre (CF 20% or NDF 44%). It is high in energy (DE 2.56 Mcal/kg), fairly high in calcium (0.68%), low in phosphorus (P) (0.1%), with only moderate protein (CP 8%) and no vitamin content. Beet pulp is available in its “raw” form, which looks somewhat like ground-up old shoe leather, or in pellets. Traditionally, the raw form is soaked in water for 1 to 12 hours before feeding to prevent choke. Soaking in hot, humid weather can result in the pulp becoming rancid. It is a very common additive in “complete” concentrate feeds. Up to 4.5 kg (10 lb.) (dry weight) can be fed to the average adult horse, but it should be supplemented with a balanced vitamin/mineral supplement and perhaps protein. Do not feed beet pulp as the sole source of nutrition. Feeding it dry (unsoaked) increases the risk of choke.

Horses should not be allowed to eat carrots free choice.
The carrots froze at night, then thawed and went moldy.
– photo by Bob Wright
2.7 Root Crops (Carrots, Turnips, Potatoes)
Cull carrots are commonly found in areas where there is extensive market gardening. Carrots are an energy dense feedstuff much like grains (DE 3.78 Mcal/kg). They have medium protein content (CP 10%) and are low in fibre (CF 9.5% or NDF 12%). This analysis is very similar to oats. They should never be fed free choice.

Other root crops (turnip, potatoes) are fed in various locations around the world as energy dense feedstuffs. With the availability of grains they have fallen out of favour for the most part. If they are fed, they should be fed soil-free. Green potatoes and plant leaves should never be fed because of a glycoalkaloid poison. Root crops carry an increased risk of choke as well as dangers from being frozen and rotting.

Manure from horses eating carrots free choice.
– photo by Bob Wright

2.8 Bran
Although bran is a fair source of fibre (CF 11% or NDF 42.5%), do not feed it to horses in large quantities for prolonged periods of time. Wheat bran is extremely high in phosphorus (P 1.18%), low in calcium (Ca 0.13%) with a high Ca:P ratio (1:9) and will cause potentially debilitating calcium/phosphorous imbalances. Feeding horses excessive amounts of bran can cause nutritional secondary hyperparathyroidism or Big Head Syndrome. Bran is also fairly high in protein (CP 17%). If feeding it as a supplement, limit it to no more than 0.45 kg (1 lb.) per adult horse per day and carefully balance the calcium/phosphorus ratio with calcium supplements. Wheat bran can also contain Fusarium-related mycotoxins during wet growing years.

Rice bran has been promoted as a source of fat (energy) for horses (DE 3.35 Mcal/kg). It, too, is a fair source of fibre (CF 12.9%) (NDF 33%). However, it has a higher concentrate of phosphorus (P 1.78%) and lower calcium (Ca 0.07%) and higher Ca:P ratio (1:25) than wheat bran. Some commercial rice-bran products have added calcium to correct the imbalance, but, as with wheat bran, rice bran is not recommended as a main component of your horses diet or as a forage substitute.

2.9 Lawn Clippings
Grass clippings are small in particle size and high in moisture content. They ferment rapidly in warm weather and can lead to colic, botulism, laminitis and/or death. Recently, horses died in California of botulism (serotypes A) as a result of consuming grass clippings.

Strategy 3: Use Alternatives only when you have to
Long-stem, dry hay should always be the main nutrient source for horses. Learn from your shortfalls this year and be prepared for next year. Look closely at the substitutes described above. Many have drawbacks and should be looked as “hay extenders,” not as replacements.

Information for this article was first developed collaboratively between Dr. Bob Wright and Dr. Sarah L. Ralston, VMD, PhD, dACVN, Associate Professor, Department of Animal Science, Rutgers University College, New Brunswick, New Jersey. Dr. Wright has authored more than 150 factsheets, information sheets and scientific publications. He also created the monthly column Horse News and Views where more than 450 snippets provided advice to horse owners. The topics of these writings were based on the many investigations he has been involved in. Much of the information can be read on wwww.horsenewsandviews.com

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