Ask the Expert: Horses per Acre of Pastures

Question: We’ve finally purchased a horse property! It’s 7 acres with about 5 acres in pasture. We have 2 horses, but are looking to expand our herd. However, we do not want more horses than what our pasture can hold since we do not want to feed hay (or much hay) during the summer. How many horses can our pasture support? 

Response: Congratulations on purchasing a horse property! The answer to your question is, “it depends”. In general, 2 acres per one 1,000-pound horse is recommended if owners expect the pastures to provide most of the horse’s nutrition during the growing season. However, this is highly variable and depends on several factors including geographical location, soil type, rainfall, and management. Although location, soil type, and rainfall are mostly out of an owners control, management can be controlled and includes mowing, fertilizing, controlling weeds, resting (e.g. avoiding over-grazing), and dragging; all recommended best practices for horse pasture management.

Your 5 acres of pasture should be able to feed 2.5 1,000-pound horses during the summer grazing season. If your farm is on sandy soil, there is a drought, or you choose not to do any pasture management (e.g. mowing, fertilizing, weed control, resting, and dragging), then 5 acres might not be enough for your two horses and hay supplementation would be needed. On the other hand, if your farm has heavier soil, there is good rainfall, and you practice good pasture management, then your pasture should be able to support your two horses, and maybe one more, during the summer grazing season. For more information on pasture management, click here

Author: Krishona Martinson, PhD, University of Minnesota. Photo credit: Michelle DeBoer, PhD, UW-River Falls.

Interpreting an Equine Hay Analysis

Most universities and equine nutritionists encourage horse owners to have their hay tested. However, most horse owners need help interpreting the results of their analysis. Below is a list of some of the primary components commonly analyzed for in hay, and a basic interpretation of each. Keep in mind that additional components can be analyzed for by request (and/or for an additional cost) and that each laboratory will have a unique display of results. Also, remember the analysis you receive is only as good as the sample you submit. For more information on taking a hay sample, click here.

As Sampled vs. Dry Matter Results

When your sample is returned, there will be two main columns of numbers; As Sampled and Dry Matter. As sampled reports nutrients in their natural state, including moisture. Dry matter reports nutrients with the moisture removed. Results reported as dry matter allow for the direct comparison of nutrients across different feeds and often simplifies the ration balancing process; therefore, we recommend owners use the percent dry matter column. In this example, this is the third column of numbers.

Moisture
The optimum moisture for horse hay ranges from 10 to 15%. Hay under 10% may be too dry, leading to brittle hay. Hays over 17% moisture have an increased risk of molding (unless propionic acid is used), and hays over 25% moisture pose the threat of severe heat damage and serve as a potential fire hazard. In the above example, the moisture of this hay is 7.8% (moisture is usually listed above the other components at the top of the report). Please note, this hay was used for a research trial, so was dried prior to analysis.

Equine Digestible Energy (DE)
DE is the measure of the digestible energy in the hay and is used to balance the energy portion of the equine diet. Most hays range from 0.76 to 0.94 Mcal/lb of DE. Different classes of horses require different amounts of DE. For example, a light working horse requires approximately 20 Mcal/day of DE. In the above example, the hay has 0.92 Mcal/lb of DE. If this hay was used to feed a horse in light work, 22 pounds of hay each day would be needed to meet the horse’s energy requirement (20 Mcal/0.92 Mcal per lb/= 22 pounds). Make sure you request an equine DE when having horse hay analyzed as sometimes the default DE calculation is for cattle.

Crude Protein (CP)
Crude protein is a measure of the protein concentration in the hay. Crude protein can range from 8 to 14% in grass hays, 14 to 17% in mixed hays, and 15 to >20% in legume hays. Hay containing approximately 12% CP is thought to meet the amino acid requirements of most adult, idle horses. Other groups of horses (e.g. lactating mares, horses in heavy work, and foals) require greater amounts of CP. If feeding hay with less than 12% CP, supplemental protein sources will likely be required. In the above example, the hay has 15.1% CP.

Acid Detergent Fiber (ADF)
ADF represents cellulose and lignin, the highly indigestible fractions of plant material. The lower the ADF value, the more digestible the nutrients in the hay are. Hays with ADF values of 30 to 35% are readily digested, while those above 45% are appropriate for feeding horses with lower energy needs (e.g. horses at maintenance). In the above example, the hay has 35.9% ADF and nutrients should be readily digested by the horse.

Neutral Detergent Fiber (NDF)
NDF is a measurement of the insoluble fiber and is classified as cell wall or structural carbohydrates. These components provide the plant with structural rigidity. The higher the NDF, the less a horse will consume; it is generally accepted as an indicator of preference. NDF levels between 40 and 50% represent hays that will be highly palatable, while those above 65% will likely not be readily consumed by most horses. However, high NDF hays can be used as “busy hays”. Both ADF and NDF can be used to help determine maturity; the higher the values, the more mature that hay tends to be. In the above example, the hay has 64.8% ADF and will likely be more slowly consumed by horses.

Non Structural Carbohydrates (NSC)
NSC is an analysis of the starches and sugars in the forage. NSC is commonly estimated by adding starch and water-soluble carbohydrates (WSC). Since some horses are very sensitive to dietary starch and sugar (e.g. horses with laminitis and metabolic syndrome), the NSC level can be helpful in selecting hay. Hays containing greater than 12% NSC should not be fed to horses diagnosed with metabolic syndromes, while NSC is rarely a concern for healthy horses. In the above example, there is 5.3% WSC and 0.9% starch for an estimated NSC of 6.2%. This example is teff hay, an annual warm-season grass becoming popular among owners managing laminitic and metabolic horses.

Calcium (Ca) and Phosphorus (P)
Ca and P are two macrominerals required in the diet by all horses in specific amounts. The levels of these minerals can vary among different types of hay. For example, legume hays have high Ca levels relative to P. For the adult, maintenance horse, the Ca:P ratio should be between 3:1 to 1:1. In the above example, the hay has 0.44% Ca and 0.39% P for a Ca:P ratio of 1.13:1. Additional minerals can be tested for if necessary.

Relative Feed Value (RFV)
RFV can be used when selecting hay but is not used in balancing equine rations. Generally speaking, higher RFV reflects higher quality, greater intake, and digestibility. An “average” hay has a RFV of 100 and most agree would be suited for horses in light work. In the above example, the RFV is 87% indicating this hay would be best suited for adult horses at maintenance.

Written by Krishona Martinson, PhD, University of Minnesota. This and other horse nutrition articles can be found at http://www.extension.umn.edu/agriculture/horse/nutrition/.

10 Ways to Optimize and Stretch Horse Hay Supplies

Weather woes; winter injury, a cool and wet spring, flooded hay fields, and frequent rainfall have tightened already short hay supplies in the Midwest, and other areas of the country are facing similar challenges. Flooded fields may have long-term damage from standing water and forage quality will likely take a hit as wet conditions delay cutting. However, horse owners still need to secure hay and should consider these strategies to optimize and stretch hay supplies.

1. Develop a good relationship with at least one horse hay suppliers. Find (and keep) hay suppliers that are trustworthy, communicate well, and produce a quality product. A good hay supplier should be willing to patiently answer questions; stand behind their product; and clearly explain their pricing, delivery, and storage structure. In turn, owners should become educated buyers, be aware of local conditions and prices, and be prepared to buy when the forage is available. Both parties should be understanding of weather conditions, be timely with communications, and be professional at all times.

2. Maximize pasture during the summer months. Utilizing pasture forage is usually a third the cost of feeding hay. Therefore, horse owners are encouraged to establish new pastures and maintain existing pastures. Pasture maintenance includes mowing, fertilizing, resting to allow for re-growth, dragging, and controlling weeds. Consider using annual forages like teff and annual ryegrass to extend the grazing season into the spring and fall.

3. Purchase hay by weight. Bale density can make bale weight estimations difficult, especially for large round and square bales. Most truck stops and gravel pits have scales and will allow loads to be weighed for a fee. Owners can use bathroom or luggage scales to weigh small square bales. For example, a 35-pound square bale sold for $5 is more expensive ($286 per ton) than a 50-pound bale sold for $6 ($240 per ton). Weighing the bales can also help owners accurately calculate annual hay needs.

4. Buy a hay type that matches your horse’s needs. In general, less mature forages are more nutrient dense than more mature forages. Likewise, legumes (e.g. alfalfa) tend to be more nutrient dense than cool (e.g. orchardgrass) and warm-season (teff) grasses. A mature grass hay will likely meet the needs of a pasture companion. However, feeding a pasture companion an immature alfalfa hay may result in overspending and horse weight gain. Always buy good quality hay with no mold, dust or weeds. Buying hay with preservatives (e.g. propionic acid) is safe for horses and will help limit mold growth in hay.

5. Have your hay tested for quality. Testing your hay will aid in feeding precision, costs about $20 per sample, and results are usually available within a few days. Choose a lab that has an “equine package” and provides equine digestible energy (Equine DE). Use the test results to calculate how much hay each horse needs to avoid over or under feeding. For example, an average grass hay may contain 0.91 mega calories (Mcals) per pound compared to a mixed grass legume hay with an average of 1.06 Mcals per pound. If an adult horse requires 16 Mcals each day, an owner would feed 18 pounds of the grass hay compared to 15 pounds of the mixed hay to meet the horse’s energy requirements. If these hays are the same price per ton, the mixed hay would be a better buy since less of it is needed to meet the horse’s energy requirement. Of course other nutrients are important, but energy is the first nutrient used to balance a horse’s ration.

6. Do not over (or under) feed. Most horses should eat 1.5 – 2.5% of their bodyweight (BW) in feed (forages plus grains) daily. For example, a 1,000-pound horse should eat 15 – 25 pounds of feed daily, with a majority (≥75% for most horses) of that being forage. Most horse owners should target 2% BW; however, owners with easy keepers or overweight horses should target 1.5% BW, while owners with hard keepers should target 2.5%. Overfeeding can result in excessive horse weight gain, related health issues, and wasteful spending. Using these values can also help owners accurately calculate annual hay needs.

7. Always use a feeder or net to reduce hay waste. When feeding small square bales indoors, 7% hay waste occurred without a feeder vs. only 1% with a feeder. When feeding small square bales outdoors, 13% waste occurred without a feeder vs. 1 to 5% waste with a feeder. When feeding round bales outdoors, 57% waste occurred without a feeder compared to 5 to 33% waste with a feeders. Although feeders can be an investment, all feeders paid for themselves within one year. Not using a feeder can result in thousands of dollars of wasted hay (and money) annually.

8. Reduce hay waste with proper bale wrap and storage. Research found that when harvesting and storing round bales outdoors, dry matter (DM) losses were nearly 20% for bales wrapped with sisal twine, 11% for plastic twine, 7% for net wrap, and minimal losses with B-Wrap®. Hay stored indoors will always result in less DM loss compared to hay stored outdoors; however, not all owners have sufficient indoor storage. When round bales were stored outdoors without cover, DM loss was 7 to 49%, compared to only 2 to 6% when stored indoors. Outdoor storage tips include covering the bales with tarps, deterring wildlife from storage areas, storing bales on a well-drained surface or pallets, baling or buying a tightly packed bale, and using older bales first. Consider building additional indoor hay storage to reduce losses and to help ride out market swings and the seasonality of hay production. Properly stored hay will keep for multiple years.

9. Explore using alternative feedstuffs. These can be economical compared to hay during times of high hay prices. Hay cubes, hay pellets, chopped alfalfa, and complete feeds can be used as total replacements for hay; however, horses tend to eat these products quickly. Other fiber sources include rice bran and beet pulp. These feeds cannot fully replace hay, but can be used as partial hay replacements. Whenever hay alternatives are used, owners should work with an equine nutritionist (and their veterinarian if needed).

10. Consider reducing herd numbers by rehoming horses that no longer meet your goals. A 1,000-pound horse, eating 20 pounds of hay daily, will eat about 7,300 pounds or 3.6 tons of hay annually. If hay is selling for $300 per ton, that is a cost of $1,080 annually. 

Authors: Krishona Martinson, PhD, Hannah Lochner, BS, Jessica Prigge, BS, and Marcia Hathaway, PhD, University of Minnesota. Photo credit: Krishona Martinson, PhD, University of Minnesota. This and other horse nutrition articles can be found at http://www.extension.umn.edu/agriculture/horse/nutrition/.

Feeding the Easy Keeper Horse

Is your horse on the higher end of the body condition score chart? Or does he seem to gain weight by simply looking at a bag of feed? Then check out these feeding tips for the easy keeper.

  1. Limit pasture grazing time. This is especially true in spring and early summer, when pasture growth is most rapid. If this is not possible, fit the horse with a grazing muzzle.
  2. Don’t feed high-fat supplements. Eliminate corn oil, flaxseed and rice bran supplements from your horse’s diet to cut out some calories and prevent excessive weight gain.
  3. Eliminate high-calorie concentrates. Instead try a ration balancer product, which is a low calorie and low starch, vitamin and mineral fortified supplement in a pelleted form that supplies the missing nutrients for a horse consuming only hay or pasture.
  4. Start an exercise program. The main purpose of exercise is to increase energy expenditure or calorie loss. Other benefits of daily exercise include an increase in metabolic rate, a possible reduction in appetite, and prevention of bone and mineral losses that may occur during calorie restriction when the horse is inactive.
  5. Replace legume hay with grass hay. Legume hay, such as alfalfa and clover, contains more calories per pound than grass hays. Instead of alfalfa, feed a high-fiber, good quality grass hay that is free of dust, mold and weeds.
  6. Limit the amount of hay fed and divide it into several daily feedings. Limit the amount of hay fed to 1.5% of body weight, which is enough to ensure body condition maintenance while keeping proper digestive function happening. If the horse’s body condition is still excessive after weight loss has stabilized, then decrease the feeding rate of hay to 1.25% of body weight or less and continue feeding management for weight loss.

At the end of the day, the name of the game is simple – your horse needs more calories being burned, than calories being consumed. It just takes some planning, and sticking with the plan for the long haul, to keep your easy keeper in ideal condition.

Ask the Expert: Maple Leaf Toxicity

Question: Our horse pasture has several maples trees. I was told they are toxic to horses, but our horses seem fine. Are they toxic? If they are, do we have to remove them from our pasture?   

Answer: Wilted (not fresh) maple leaves are toxic to horses. However, horses must eat 1.5 to 3 pounds of wilted maple leaves per 1,000 pounds of bodyweight to become sick.  Wilted maple leaves can remain toxic for four weeks, but they aren’t generally believed to retain toxicity the following spring. Thus, illness normally occurs in the fall when normal leaf fall occurs. 

Illness from maple leaves has only been reported in horses. Common signs after the first day of eating leaves include depressed behavior, tiredness, not eating, and dark red/brown urine. Signs may progress to going down with labored breathing and increased heart rate before death. Don’t cut down maple trees in horse pastures. Instead, keep branches out of reach of horses (for example, trimmed above their reach) and fence horses out of areas with a lot of wilted maple leaves. However, horses will rarely choose to ingest wilted maple leave unless very hungry. For more information on wilted maple leave toxicity, click here

Written by Krishona Martinson, PhD, University of Minnesota. This and other horse nutrition articles can be found at http://www.extension.umn.edu/agriculture/horse/nutrition/.

Frost Concerns for Grazing Horses

Photo Credit: Krishona Martinson, PhD, University of Minnesota

Fall can be a beautiful time of year for horseback riding. However, frost can negatively impact horse health during fall grazing. 

There are no reports of toxicity of horses grazing frost damaged pastures (includes grass and legume species). However, frost damaged pastures can have higher concentrations of nonstructural carbohydrates, leading to an increase in potential for founder and colic, especially in horses diagnosed with or prone to obesity, laminitis and Equine Metabolic Syndrome. To help prevent these health issues, wait up to a week before turning horses back onto a pasture after a killing frost. Subsequent frosts are not a concern as the pasture plants were killed during the first frost.

Why do nonstructural carbohydrates increase during the fall? During the day, plants carry out the process of photosynthesis. In this process, they make carbohydrates as an energy source for the plant. A second process, respiration, is carried out when the plants use up the carbohydrates they produce during the night for energy. Plant respiration slows down when temperatures are near freezing. As a result, the plants hold their carbohydrates overnight. Freezing can stop respiration and lock the carbohydrates in the plant for over a week. Thus, plants tend to contain more carbohydrates in colder temperatures or after a frost. Often, horses will prefer forages after a frost due to the higher carbohydrates levels.

For more information on fall health concerns for grazing horses, click here

Written by Krishona Martinson, PhD, University of Minnesota. This and other horse nutrition articles can be found at http://www.extension.umn.edu/agriculture/horse/nutrition/.
  

Ask the Expert: Feeding Preservative Treated Hay

Photo Credit: Krishona Martinson, PhD, University of Minnesota

Question: Our regular hay supplier applied a preservative (propionic acid) to the bales this year. What is that and is it safe for horses?   

Answer: Preservatives are commonly used during times of frequent rainfall or poor drying conditions (e.g. high humidity or heavy dew). Propionic and acetic acids are commonly used hay preservative that are applied to hay as it is baled to allow baling of wetter than normal hay without spoiling during storage. Moisture at the time of baling is directly related to mold formation. Hay baled at ≤15% moisture is unlike to mold; however this is impacted by bale-type and mass. For example, small square bales can be baled up to 18% moisture with limited risk of mold formation; however, large round bales must be baled at ≤15% moisture to reduce the risk of mold formation. Preservatives are most effective at inhibiting mold growth, and most economical, when the hay is baled between 18 to 25% moisture. 

Preservatives are safe for use in horse hay. Researchers found that when given a choice, horses preferred hay that was not treated with a preservative; however, horses readily consumed the treated hay when a choice was not given. Yearlings receiving hay treated with a preservative consumed and gained just as much as yearlings consuming untreated hay, and clinical measures of well-being were not affected by consumption of preservative-treated hay. Interestingly, a horse’s hindgut bacteria actually make propionic acid as a result of microbial fermentation.

Therefore, feeding horses hay treated with a preservative is a safe and common practice, especially in years when poor weather conditions exist for making hay, and helps to inhibit mold growth during storage.

Written by Krishona Martinson, PhD, University of Minnesota. This and other horse nutrition articles can be found at http://www.extension.umn.edu/agriculture/horse/nutrition/.

Maintaining Body Condition in Hot Weather

It may seem like common sense, but a horse that is overweight is a horse that will struggle in warmer temperatures. The fat on a horse acts as insulation, great in the winter, but come summer this is a major issue. An obese horse in the summer can result in heat stress. This is why it’s vital to keep tabs on your horses’ body condition score during all seasons.

A proper body condition score (BCS) for growing and performance horses, as well as general-use horses, should be kept at 4-7, with a 5 being “ideal”.  Broodmares should generally be kept at a 5.5-7.5.

Weight tape (or a scale) can be used to monitor changes in the horse’s body condition. A weight tape may not be very accurate for estimating exact body weight for a particular horse, but it is consistently accurate at discovering changes in your horse’s weight. Take the measurement every 30 days, applying the tape at the same location around the heart girth and behind the withers, and maintain the same tension on the tape each time you use it. The results of your monthly measurements can be used to adjust your horse’s feeding program to maintain a constant and desirable body weight and body condition score.

Learn more about proper body condition scoring here.

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