Omega Fields

  • Complications with feeding clover

    Written By: Mike Murphy, DVM U of M

    Clover is a desirable feed source for most horses whether used in pasture or in hay because it provides useful energy and acceptable protein and fiber. Problems may rarely arise with clover, just as they can with most desirable feed sources. Clover may be "too rich" at times for horses. The early rapid growth phase of some clovers, like other forages, may contain high amounts of soluble sugars. The soluble sugar content of the plant will decrease as it matures. These soluble sugars and other carbohydrates are sometimes associated with colics and founder in horses fed only pasture in the early spring.

    Growth of mold on clover is occasionally encountered. Two mold problems are generally associated with the common pasture clovers (red, white and alsike). They are associated with weather above 80°F and humidity above 60%. The most well characterized problem is "slobbers." Horses can literally fill several 5 gallon buckets full of saliva in one day. This condition is caused by slaframine, which is produced when red clover is infested with a mold. The mold is generally a rust color seen on the upperside of the leaf. This mold normally "runs its course" in 2 to 4 weeks, depending on weather conditions.

    The second problem in these clovers, black blotch disease, is not quite as well characterized, but has been reported in Minnesota, Washington, and areas of Canada. The mold literally causes black blotches to occur on the underside of the clover leaves, usually closer to the ground where the humidity is higher. Horses ingesting clover with black blotch have been known to develop excessive "sunburn," which is really a thickening and reddening of the white areas of skin due to liver damage. Black haired horses also get the liver damage but the "sunburn" is not visible.

    A third mold condition affects a different clover both white and yellow sweet clover. These clovers are not common in pasture mixes, but are more frequently seen along roadways. The problem arises not from clover in pastures but if sweet clover is harvested for hay AND gets moldy as the hay is baled. Crimping the sweet clover at cutting reduces, but may not entirely eliminate, this problem. An unknown mold converts the naturally occurring cumarol in the sweet clover to dicumerol a blood thinning drug. Horses may bleed if moldy sweet clover hay is a substantial amount of a horse's diet over a number of days. Dicumerol clears quickly, so taking the horse off the hay is the best choice. Injections of vitamin K or blood transfusions may be necessary in extreme bleeding situations.

    However, even with these potential problems, clover is still considered a desirable forage for horses.

    Permission granted for reprint of article from University of MN Extension. To read more articles from U of M Extension please visit their A to Z library >>>

  • Unitended Consequences

    Written By Walt Friedrich

    In an earlier article we examined the horse's natural way of communication with others of his species, and how, by domestication, he uses those same natural ways with us. It's the only "language" he knows, and it's virtually all body language. Because neither of us is perfectly fluent in the other's language, misinterpretations can (and do) occur, and when someone is hurt as a result, it's usually a human. This brief series is intended to suggest some of the conditions that can result in unintended but serious damage to ourselves.

    Since we're not horses, we're limited to "reading" our horse from a human perspective, and we can "get it" wrong - and he can misinterpret us as well. For example, we like to "pet" him with our hands, as a way of showing our love and appreciation of him. But horses are very conscious of their personal space, and except for human and equine “friends”, do not allow others into it without an invitation. Sometimes, our horse rejects what we intend as overtures of friendship and mutual admiration. How often have you raised your hand to his nose, just to render a brief pet, only to have him turn away emphatically?

    His action may not mean that he doesn't want our affection; it usually does mean that we've invaded his private space, and he protects it. Fortunately, most often his reaction is as mild as just turning away - another horse invading his space without invitation may well get at least a nip, possibly much more than that as he defends his personal territory.

    The point is to use caution in treating him as a human or even a pet pooch. Though we may have the best of intentions, his misinterpretation could result in our receiving a serious reprimand in the form of a kick or a nip…or worse.

    He can also do us serious damage with no intention at all to do so. Consider: as prey animals his kind discovered ages ago that long life is much more dependent on an ability to escape danger than to take it on and fight it out. And with threats like perpetual lunch-hunting mountain lions sharing his environment, escaping a threat calls for instant action and great speed, letting nothing stop or even delay him. Horses are huge animals of great power, and they dance to their own music, not ours; his sudden reaction to an unexpected touch of our hand on his nose should be taken as a tiny hint of what can happen if we're in the wrong place at the wrong time.

    His needs are far different from his predatory neighbor’s. He's got some pretty good defenses to keep the big cats at bay; he knows his territory down to blades of grass; as a healthy adult he's faster than the big cats (except for the cheetahs, but they don't share his territory); and he's extremely quick to react to danger. Instant escape and tremendous speed and endurance are his only true defenses, and he takes no chances.

    To illustrate the difference between him and us, consider this hypothetical: you and I and a horse are standing in a pasture, chatting, all nice and close to each other, when a prankster sets off a firecracker just behind the horse. Your reaction and mine is to immediately look toward the sound to determine what it was, and then decide if we need do anything about it. In other words, we think about it, just for a second or two. But what does the horse do? He's instantly at full speed, running like blazes at virtually the moment of the sound, because his instinct yelled, “mountain lion!” - no time for thinking. If you or I are in his path, too bad for us - he runs right through us to escape, and we could be just lucky to survive.

    Why on earth is there such a different reaction? You and I can tell very quickly whether or not a sudden situation is an emergency, because rather than to run, our first reaction is to look and evaluate, and then take whatever action we deem necessary. But that takes time. In his case, survivors of his species learned through the millenia that the sudden presence of a predator means they'll either get moving or they'll be the mid-day meal. No time to think, even a few milliseconds can make the difference, so he doesn't bother to look, he's just gone.

    Good thing, too, because his vision, although superb, has an "Achilles Heel”. A brief explanation here of equine vision: with eyes located on the sides of his head, a horse has almost 360 degree vision. Each eye "sees" independently of the other, affording him superior peripheral vision; but while monocular vision is great for awareness, it has no depth perception, meaning the horse has difficulty in determining distance using just one eye. (He switches to binocular mode by turning his head to view with both eyes simultaneously, resulting in superb vision - in 3-D and with depth perception.) Further, his monocular vision is slow to focus, meaning it takes measurable time for him to see clearly, and although it's a matter of just milliseconds, it's too long when the view is of a mountain lion.

    And so because his inability to recognize and identify instantly what he sees can be dangerous for him; his instinct is to move first and look back later, from a safe distance. The problem for us is that when we’re near him when he spooks, we’re in danger of his taking us out as he escapes – and he’ll spook from many more causes than just the sudden bang of a firecracker. You can't stop him from running through you; it can happen much quicker than you can react to avoid it.

    But you can prevent it; he's your horse, and you want to spend quality time with him and not be paranoid about it. So when you're with your horse, it's excellent practice to form the habit of being always aware of your surroundings, and never in his potential flight path if he were to spook. We all know that hanging around his butt puts us in the line of fire from his howitzers (hind feet), but pay attention to his front as well, because that's the way he'll run. When you're dealing with his feet, stay on yours - don't sit as you do footwork on him, but rather, bend - even though it can be hard on the back. Don't daydream when you're on saddle - pay attention to your surroundings. And it's always wise to avoid cramped quarters when you and your horse are together -- his reaction to a fly bite can be enough to get you squashed and stomped.

    This has been Part 2 in a series of writings intended to explain some fundamental differences - those that can get you into trouble -- between your world and your horse's. Please watch for future explorations of these differences.

  • Just Being

    Written By Jenny Pavlovic

    Earlier this year I wrote about taking a therapy dog class with Cay, and how far she’s come since she first arrived here as a practically-feral adolescent 8 years ago. I had decided to enter Cay in the class because of the response she’d shown to my niece’s children, fetching the ball over and over for a 3 year old boy, when she had never fetched the ball for me. She came alive while playing with those kids, and I thought she might like to become a library dog, like Chase, and have kids read to her.

    In the therapy dog class, Cay made many friends and learned to do all of the exercises required to pass the Pet Partners therapy dog test. She sat on command, came when called, walked nicely by my side, and walked through a crowd. She let a stranger brush her and touch her. She even learned to be calm around wheelchairs and funny noises and people who move differently. She did very well, considering she was afraid of practically everything when I first met her.

    After graduating from the class, we were scheduled to take the Pet Partners test the following week. Cay seemed to be ready for the real test since she had passed all of the exercises in class. But she had hurt her leg and was limping, so she was unable to take the test. We rescheduled at a later date and Cay and I continued to practice.

    When the big day came, we started out well enough. But when I told Cay to sit, she just looked at me. She knows the word and knows how to sit, but for some reason she didn’t want to. We tried again and she just didn’t do it. Isn’t it odd that she didn’t do the exercise that most dogs know, the one that was supposed to be the easiest?

    I wasn’t particularly nervous since I’d easily passed the test with both Chase and Bandit in the past. I just wanted Cay and me to give it our best shot. Still, I could tell she was stressed by the test environment, with everyone in the room focusing on her. When we were in the class, with other teams in the room the attention was divided.

    I thought about the test and what was different and how I might have helped Cay better. I tried to stay relaxed, perform my part consistently and do my best to support her. I even gave her calming signals. The message I got from her is that she really wasn’t that interested in doing the exercises. After working with Bandit, a dog who competed in multiple types of performance events for many years and always did what I asked, and then with Chase, who is a natural therapy dog who has always done what I asked, I had to pause and think about what was happening with Cay. Although she had done very well in the class, she wasn’t comfortable in the test environment. I had to listen to what she was telling me.

    Cay doesn’t want added stress in her life. She doesn’t want to work to become anything, she just wants to be herself. She wants to hang out together, go for walks on the hill and by the river, and not strive for anything in particular. She wants to enjoy one another’s company, enjoy the day, and celebrate life. We can all learn from her.

    Each dog has lessons to teach us. I thought Cay wasn’t hearing me when I told her to sit, but maybe I wasn’t listening to her. And she’s right. We could all use more time to just enjoy the day.

    You could say we failed the therapy dog test. But I learned to listen better. Take it from Cay: Don’t let the whole summer get away from you without taking time to relax and enjoy the day with your pups. Cay has come a very long way over the years and I think she would be a great therapy dog. I may consider taking the test with her again in the future, but that will be up to her. I’ll keep listening and we’ll see. For now, we’re taking time to celebrate life.

    With all that’s happening here this summer, Cay has taught me a valuable lesson. In August the kids will visit and Cay will get to play ball with them. Who knows, maybe they’ll even read to her.


    Cay has allergies this time of year. Omega Fields Canine Shine and Omega Nuggets keep her skin and coat healthy and keep her from feeling itchy.

  • Make better use of round-bales

    Written By: Krishona Martinson, PhD, University of Minnesota

    Drought conditions have severely reduced the supply of hay and other feedstuffs, escalating the demand and driving up prices. Horse owners can reduce hay waste by using feeders and properly storing hay, especially when feeding round-bales.

    In a study conducted in MN, feeding round-bales to horses without a feeder resulted in 57% waste. All nine round-bale feeders tested reduced hay waste, and ranged from 5 to 33% hay waste.

    Research has shown outdoor hay storage losses can range from 5 to 35% depending on precipitation, storage site, and original condition of the bale. For example, the outer 4" layer of a 6' diameter round-bale contains about 25% of the total bale volume, and is most likely to be damaged by weather if stored improperly or unprotected.

    There are a number of techniques that minimize outdoor storage losses:

    1. Bale (or buy) a dense bale as the bales will sag less and have less surface area in contact with the ground.
    2. Use plastic wrap, net wrap, or plastic twine. Research showed that net wrapped bales reduced grass hay dry matter losses by 32% compared with twine bales when stored outside.
    3. Store bales on a well-drained surface. A well-drained, 4-6" coarse rock base will minimize bottom spoilage, as well as using wooden pallets.
    4. Never store bales under trees.
    5. Storage losses are usually reduced by approximately two-thirds with indoor storage and by one-half with good plastic covering (i.e. a tarp) outdoors.

    Permission granted for reprint of article from University of MN Extension. To read more articles from U of M Extension please visit their A to Z library >>>

  • Chokecherry

    Written By: Krishona Martinson, PhD, Lynn Hovda, DVM, Mike Murphy, DVM, PhD, and Patrick Weicherding, PhD, University of Minnesota

    chokecherry in bloom

    Chokecherry in bloom

    fall leaf color of chokecherry

    Fall leaf color of chokecherry

    Chokecherry: Prunus virginiana

    Origin: Native to Canada, chokecherry is a widely planted species that has been cultivated since 1724.

    Lifecycle: Chokecherry is a perennial tall shrub or occasionally a small tree.

    Identification: Chokecherry reaches a mature height of 6 to 10 feet and has an irregular, rounded top, often with a crooked or leaning trunk. The leaves are toothed and usually ovate. The long spikes of flowers bloom in June and the “cherries” ripen in August.

    Distribution: Found from Newfoundland to Saskatchewan and south to North Carolina and west to Kansas.

    Habitat: Chokecherry commonly grows on open sites with rich, moist soils, such as along fence rows and streams, on cleared land, and bordering wooded areas. It is relatively intolerant of shade.

    Control: All chokecherries, and other cherry species, should be removed from horse pastures. Do not plant cherry species in horse pastures.

    Toxin: Cyanide.

    When toxic: Cyanide is released from the cyanogenic glycoside (precursor to cyanide) after chewing the forage or seed, or wilting of the forage (i.e., after a frost). The cyanogenic glycoside may be present in higher concentrations in the forage of a young or rapidly growing plant.

    Toxicity: Members of the Prunus (cherry) genus of plants have varying amounts of cyanogenic glycosides in the leaves and seeds of the plants. The Agucatillo (P. brachybotrya), cherry laurel (P. laurocerasus), black, wild, or rum cherry (P. Serotina) and chokecherry (P. virginiana) tend to have more cyanogenic glycoside in the foliage. Apricots (P. armeniaca) and peaches (P. Persia) tend to have more cyanogenic glycoside in the seeds.

    Signs and effects of toxicosis: Animals are most commonly found dead within minutes to a few hours of ingestion of the plant. Rarely, terminal seizures may be observed.

    Treatment: The opportunity for treatment is rare. Sodium nitrite and thiosulfate may be administered in an attempt to treat cyanide toxicity.

    Other information: The fruit of chokecherry (and other cherry species) is not poisonous to humans and is commonly used for making jams, jellies, pies, sauces, and wines.

    Thanks to the following fact sheet reviewers: Ron Genrick, Assurance Feeds and Harlan Anderson, DVM. Photos provided by Krishona Martinson, PhD, University of Minnesota.

    Permission granted for reprint of article from University of MN Extension. To read more articles from U of M Extension please visit their A to Z library >>>

  • Carbohydrates: the good, the bad, and the ugly

    Written By Marcia Hathaway, PhD, University of Minnesota

    It is usually the amount of carbohydrates fed at one time, not the inclusion of carbohydrates, that causes problems.

    Carbohydrates are a hot topic in the horse industry. Carbohydrates are essential in all horse's diets. There are, however, different kinds of carbohydrates found in horse feeds.

    The good: The most common kind of carbohydrate is cellulose present in forages. Cellulose is digested by microbes that reside in the horse's hindgut. The microbes break the cellulose down into individual sugars; using the sugars themselves. As a by-product of that process. they produce volatile fatty acids which the horse can absorb and use as its primary energy source. In many cases, all of a horse's energy requirements can be met by forages.

    More good: Another common kind of carbohydrate is starch; present in high quantities in cereal grains, like oats, corn and barley. Starch is digested into individual sugars by enzymes produced by the horse in its foregut. There, the individual sugars can be absorbed by the horse and used as an energy source if the horse requires more energy than can be provided from forages alone.

    The bad: If the horse's capacity to digest and absorb the sugars from starch is not adequate, the sugars pass from the foregut to the hindgut. The amount of starch that can be digested and absorbed in the foregut depends primarily on the amount of starch fed and the amount of time it spends in the foregut, before it is pushed along the gastrointestinal tract and into the hindgut. A general rule of thumb is that no more than 0.5% of the horse's body weight in cereal grains should be fed in one meal. For a 1,000 pound horse, it can digest and absorb the sugars from 5 pounds of cereal grains at one time. To feed more than that amount runs the risk of overwhelming the horse's digestive and absorptive capacity of the foregut and consequently having starch overflow into the hindgut. If more than 5 pounds of grain is necessary per day, it should be divided into two feedings per day.

    The ugly: If starch overflows the foregut and enters the hindgut where microbes utilize it as their personal energy source, the by-products produced in this scenario result in a more acid environment that alters the microbe population and the integrity of the lining of the hindgut. Both of these changes are hazardous to the health of the horse and can potentially lead to laminitis and founder.

    Take home message: it is usually the amount of carbohydrates fed at one time, not the inclusion of carbohydrates, that causes problems in the healthy horse.

    Permission granted for reprint of article from University of MN Extension. To read more articles from U of M Extension please visit their A to Z library >>>

  • Carpometacarpal syndrome

    Written By:Erin Malone, DVM, University of Minnesota

    carpometacarpal syndrome

    In recent years, researchers at the University of Minnesota Veterinary Medical Center have identified a crippling form of arthritis that seems to primarily affect Arabian horses, at least in the upper Midwest. This syndrome involves apparent instability of the carpus (foreleg "knee"). This eventually leads to a bony reaction that resembles the callus from a healing fracture and can be seen on the inside of the leg.

    The bone tries (and occasionally succeeds) to bridge the lowest joint in the carpus in order to increase its stability. This is a low motion joint and would not be missed if it were to fuse but the inflammation affects the upper joints. In other words, by the time the lower joint fuses, the upper joints are also arthritic.

    Horses have a gradual onset of increasingly severe lameness that seems to coincide with the development of the bony protruberance on the inside of the carpus (see photo). The affected horses resent flexion of the carpus (i.e. can be sore after farrier work). Most affected horses are lame enough that they cannot be ridden.

    To further investigate this, we found 31 horses with the unusual form of carpometacarpal joint arthritis. 74% of the affected horses were Arabian. The problem affects older Arabians, and the average age at presentation for the initial diagnosis was 14.4 years. It seemed to affect mares and geldings at even percentages. In 7 horses, both forelegs were affected. Two horses were still in work when evaluated but the others were too lame for riding. None of the horses had previous leg surgery but 8 had known episodes of trauma to the carpus. At the time of the study, 10 horses had been euthanized for severe lameness. Five horses lived over 5 years after being retired from riding. Four of the affected horses were necropsied (autopsied), and the anatomy of the carpometacarpal joint was examined.

    During the necropsies, two different types of connection between the medial splint bone and the cannon bone were found. In most horses, these bones contact each other at two sites. In some, the caudal articulation (back connection) is missing, leaving a gap between the bones. In Minnesota, 46% of Arabians and 13% of non Arabians are missing this articulation and have the gap. When horses in California and Florida were examined, this type of anatomy was not seen. When the bones were examined, the Arabians in California did not have a missing connection.

    Based upon our work, we suspect that horses having a gap in the back part of the carpometacarpal joint cannot withstand trauma to the carpus as well as other horses. Injury could then lead to instability and arthritis. Obviously injuries cannot be prevented (particularly in horses) but the increased risk in Arabians makes it important that we recognize the problem and deal with carpal injury more aggressively than is routine. Surgery to fuse the lower joint may help prevent the continued joint degeneration and allow these horses to remain in work.

    Permission granted for reprint of article from University of MN Extension. To read more articles from U of M Extension please visit their A to Z library >>>

  • Harvest moisture and bale wrapping affects forage quality and mold in grass round-bales

    Written By:Krishona Martinson, PhD and Craig Sheaffer, PhD, University of Minnesota Wayne Coblentz, PhD, USDA-ARS Dairy Forage Research Center


    mature orchardgrass hay_ first cutting_1

    Figure 1. Mature orchardgrass hay (first cutting)

    temperature data loggers_2

    Figure 2. Temperature data loggers

    inidividual bales warpped in plastic_3

    Figure 3. Individual bales wrapped in plastic

    Harvesting hay can be complicated by poor drying conditions (i.e. high humidity and heavy dew) and the threat of rainfall [1]. In an effort to avoid rain and other adverse weather conditions, hay is often baled before it is dried to recommended moisture levels, resulting in mold development and reduced forage quality [1]. Hays baled at moisture levels less than 15% are assumed to be relatively stable, and typically exhibit little evidence of microbial respiration [1]. The development of mold in baled hay is positively correlated with the moisture concentration of the hay at baling [2]. It is common knowledge that horses are highly sensitive to several molds, and that ingesting moldy feed can result in both short-term and long term respiratory problems, specifically heaves, and gastrointestinal problems, such as colic [3].

    In Sweden, researchers investigated wrapping individual round bales of grass hay in plastic at 35% moisture [4]. Wrapping bales at this moisture level resulted in minimal fermentation, and the resulting forage was offered to equines without causing adverse health effects. The objectives of this research were to determine the effects of initial bale moisture and plastic wrapping on mold formation in large-round bales of orchardgrass hay.

    How the research was conducted

    Over a 2-year period (2008 and 2009), 40 4 x 5-foot round bales (16 in 2008; 24 in 2009) were baled and tied with three revolutions of net wrap from a 37-acre orchardgrass (Dactylis glomerata L.) hay field (Figure 1). All harvested forage was obtained from the initial growth (first crop). Targeted moisture ranges at the time of baling included less than 15%, 18 to 25%, and 30 to 35%. Moisture at time of baling was estimated with a forage moisture probe and later confirmed through forage analysis. The bales were stored outside on a well-drained sod surface in one continuous row running east and west. Bales within a treatment were butted tightly against each other, and non-treatment bales were placed between treatment groups and on both ends of the row. Each year, the treatments were applied in a completely randomized design with four replications. In 2008, treatments included the three moisture targets without plastic wrap, and bales made at 30-35% moisture that were individually wrapped with plastic. In 2009, plastic wrapping was added to all three moisture targets, resulting in six baling treatments. Wrapping cost approximately $10 per bale.

    Immediately following baling, each bale was cored six times, and samples were analyzed for forage quality by a commercial forage testing laboratory. Forage quality components included moisture content, crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), equine digestible energy (DE), calcium (Ca) and phosphorus (P). After sampling, three temperature data loggers were placed in each bale about 24 inches from either flat end of the bale at depths of 15, 28 and 45 inches from the top of the bale (Figure 2). After temperature sensors were placed, designated bales were immediately wrapped six times with one mil plastic wrap with a bale wrapper (Figure 3).

    Temperature sensors recorded temperature every hour for 7 (2008) or 10 (2009) weeks. After the temperature sensors were removed, six additional cores were taken from each bale to determine forage quality and mold counts. Data were analyzed and significance was declared at the P < 0.05 level of confidence.


    Moisture content and bale temperature

    Initial bale moisture differed among treatments. However, the low moisture treatment in 2008 was slightly greater (17%) than the target moisture range of less than 15%. However, this moisture content proved to be critically important. Other moisture contents at the time of baling were within or near moisture targets (Table 1) and were harvested in 2009. Maximum bale temperature for 21 and 33% moisture at baling was much greater compared to 12% moisture at baling. All other treatments had similar maximum temperatures compared to 12% moisture. Spontaneous combustion becomes a concern when internal bale temperature reaches 150°F and is likely at 190°F. Spontaneous combustion was not observed in this study, but unwrapped bales baled at higher moisture contents exhibited heat damage (Figure 4).

    Table 1. Initial bale moisture content, temperature, and mold counts for orchardgrass round bales

    Initial bale moisture (%) Maximum temperature (°F) Mold counts (cuf/g)
    Unwrapped bales
    12 115 26,000
    17 113 24,800,000
    21 145 7,100,000
    33 180 5,300,000
    Wrapped bales
    12 120 51,000
    18 122 19,000
    26 109 260,000

    Mold counts

    Twelve percent moisture bales had lower mold counts compared to bales baled at 17 to 33% moisture and were not different compared to wrapped bales, regardless of initial bale moisture. Aspergillus mold species were found in all treatments except 12% moisture, cladosporium was found in all unwrapped treatments, and fusarium was found in the 17 and 12% moisture bales and the 18 and 26% moisture wrapped bales. Asperigillus and fusarium species are commonly found in insufficiently dried hay and can lead to production of mycotoxins [5].


    Our results agree with previous research that determined alfalfa (Medicago sativa L.) and mixed grass-legume hays baled at moisture concentrations less than 15% are relatively stable in terms of mold growth and forage quality [6]. Orchardgrass hay baled at 12% had low mold counts compared to unwrapped bales harvested at 17 to 33%. In contrast, large round bales of mixed alfalfa-orchardgrass hay were prone to spontaneous heating when initial concentrations of bale moisture were greater than 16% [6]; which is consistent with our results.

    Although both 12 and 17% moisture bales had similar maximum temperatures, the difference between mold counts can be partially explained by heating degree days (HDD). Accumulated HDD are the summation of the daily increments by which the average internal bale temperature was greater than 86°F. In other words, the unwrapped bales in our study remained warmer longer, which is an indication of microbial activity or molding, and likely provided a better environment for mold growth. The 12% moisture bales resulted in 47 HDD compared to 209 HDD for the 17% moisture bales.

    In comparison, the 33% moisture bales resulted in over 1,200 HDD and the extremely high maximum temperature likely killed some of the mold, resulting in a lower amount of mold for this treatment compared to the 17 and 21% moisture bales (Figure 4).

    Orchardgrass hay baled at greater moisture concentrations (i.e. greater than 17% and unwrapped) resulted in reduced forage quality, mainly though increases in fiber components (NDF and ADF). Increased concentrations of fiber components in higher moisture hays have been reported for other forage species [1]. Changes in fiber components are thought to occur primarily by indirect mechanisms, where the respiratory activity of microorganisms has a concentrating effect on fiber constituents by preferentially oxidizing non-fiber components [1]. These deleterious changes in forage quality also affected livestock utilization negatively when heat-damaged bermudagrass (Cynodon dactylon L.) was offered to steers [7].

    When we baled orchardgrass at 17% moisture, mold counts were similar to unwrapped hay baled at 21 and 33% moisture. Based on these findings, we conclude that orchardgrass packaged in large round bales is susceptible to molding and forage quality losses at relatively low moisture concentrations.

    Previous research has demonstrated that wrapped orchardgrass round bales at moisture concentrations of 46% were relatively stable after unwrapping for as long as to 32 days during the winter [8]. Hay wrapped at 35% moisture was fed to equines without causing adverse health effects in Sweden [4]. Others have observed surface mold between the hay and plastic wrap when dry hay (less than 15% moisture) was wrapped [8].

    All feeds contain some level of mold, even feeds properly harvested and stored. Table 2 outlines feeding risks and cautions developed for livestock based on mold counts (mold counts total the amount of all mold species found in a sample). Using these recommendations, all wrapped forage and 12% moisture bales would be considered desirable equine forage. Seventeen to 33% moisture unwrapped bales resulted in greater than 5 million cfu/g of mold, and were not appropriate equine feeds. Because horses appear to be more sensitive to mold compared to other livestock, we recommend horse feed (hay or grain) contain less than 1 million cfu/g of mold.

    Table 2. Livestock feeding risks* at various mold counts

    Mold count (cuf/g) Feeding risks and cautions**
    Under 500,000 Low risk
    ½ to 1 million Relatively safe
    1 to 2 million Feed with caution
    2 to 3 million Closely observe animals and performance
    3 to 5 million Dilute with other feeds
    Over 5 million Discontinue feeding

    * Risks refer primarily to effect of mold without regard to possible mycotoxin content. Dust may also reduce feed consumption.

    ** Adapted from Adams RS, Kephart KB, Ishler VA, Hutchinson LJ and Roth GW. Mold and mycotoxins problems in livestock feeding. The Pennsylvania State Univ. College of Agricultural Sciences and Cooperative Extension publication 1993. DAS 93-21. 16 pgs.


    heat dampage note dark color caused by high moisture at baling_4

    Figure 4. Heat damage (note dark color) caused by high moisture at baling

    Maintaining forage quality and reducing mold growth was achieved by baling dry (12%) hay or wrapping, regardless of initial moisture, round bales of orchardgrass hay. Therefore, the current moisture threshold of 15% for safe storage of other hays also is appropriate for orchardgrass.

    This recommendation should be carefully followed; orchardgrass bales were prone to significant molding and forage quality losses at moisture concentrations (i.e. 17%) slightly greater than 15% moisture. This abrupt line between high-quality and moldy hay is likely one reason some horse owners assume it is difficult to harvest and feed quality round bales to horses.

    Wrapping higher-moisture orchardgrass round bales is an effective method for maintaining forage quality. However, the stability of higher moisture bales after unwrapping and during feeding, especially during the summer months or with intermittent feeding schedules, needs further investigation.

    Acknowledgements: This research was funded by a grant from Midwest Forage Association with additional support from Kemin Industries, Inc. and Cropland Genetics.

    Literature Cited

    1. Rotz CA and Muck RE. Changes in forage quality during harvest and storage. In Proc Natl Conf on Forage Quality, Evaluation, and Utilization, Lincoln, NE. ASA, CSSA, and SSSA, Madison, WI. 1994;828-68.
    2. Roberts CA. Microbiology of stored forages. In KJ Moore and MA Peterson (ed). Post-harvest physiology and preservation of forages. CSSA Spec Pupl 22. ASA and CSSA Madison, WI. 1995;21.
    3. Smith TK and Girish CK. The effects of feed born mycotoxins on equine performance and metabolism. Mycotoxins in Farm Animals. Transworld Research Network 2008;48-70.
    4. Muhonen S, Julliand V, Lindberg JE, Bertilsson J and Jansson A. Effects on the equine colon ecosystem of grass silage and haylage diets after an abrupt change from hay. J Anim Sci 2009;87:2291-98.
    5. Raymond SL, Heiskanen M, Smith TK, Reiman M, Laitinen S, Clarke AF. An investigation of the concentrations of selected fusarium mycotoxins and the degree of mold contamination of field-dried hay. J of Equine Vet Sci 2000;20(10):616-21.
    6. Montgomery MJ, Tineo A, Bledsoe BL and Baxter HD. Effect of moisture content at baling on nutritive value of alfalfa orchardgrass hay in conventional and large round bales. J Dairy Sci 1986:69:1847-53.
    7. McBeth LJ, Coffey KP, Coblentz WK, Hellwig DH, Turner JE and Scarbrough DA. Impact of heatingdegree- day accumulation during storage of bermudagrass hay on in situ degradation kinetics from steers. Anim Feed Sci Technol 2003;108:147-158.
    8. Rhein RT, Coblentz WK, Turner JE, Rosenkrans, Jr CF, Ogden RK and Kellogg DW. Aerobic stability of wheat and orchardgrass round-bale silages during winter. J. Dairy Sci 2005;88:1815-26.Photo Credits: K. Martinson, Univ. of Minnesota
    9. Manuscript Citation: K. Martinson, W. Coblentz and C. Sheaffer. The Effect of Harvest Moisture and Bale Wrapping on Forage Quality, Temperature, and Mold in Orchardgrass Hay. Journal of Equine Veterinary Science. DOI: 10.1016/j.jevs.2011.05.003
    10. Reviewers: Harland Anderson, DVM and Jim Paulson, Univ. of Minn.

    Permission granted for reprint of article from University of MN Extension. To read more articles from U of M Extension please visit their A to Z library >>>

  • Selecting and storing horse hay

    Written By: Krishona Martinson, PhD and Paul Peterson, PhD, University of Minnesota Extension

    There are several characteristics horse owner should use to evaluate and purchase hay for their horses.

    Content / Species

    An alfalfa grass hay mix

    Figure 1. An alfalfa grass hay mix

    Mature grass hay heads

    Figure 2. Mature grass hay (heads)

    young grass hay no heads

    Figure 3. Young grass hay (no heads)

    interaction of forage quality and yield

    Figure 4. Interaction of forage quality and yield

    Determine the percent of grass and/or legumes in the hay (Figure 1). Common grasses include orchardgrass, bromegrass, timothy, fescue, reed canarygrass, and bluegrass. Common legume species include alfalfa, red clover, white clover, and sweet clover. In general, legumes (like alfalfa and clover) have a higher protein content than grasses, and leaves have more protein than other parts of the plant . Protein content of hay is also affected by stage of maturity at time of cutting, protein content decreases as the plant matures. In many cases, pure alfalfa hay has more protein than what the average horse needs. Although this will not affect the horse's health, it will increases water requirements and cause more urination that is high in ammonia. Some legumes are hard to dry (like red clover) when making hay, and therefore are at higher risk of molding.

    Stage / Maturity

    As forage plants mature, the nutritional value changes. Plants have more fiber and less protein as they mature. Indicators of maturity for legumes are flowers, and seed heads for grasses (Figure 2). Thick stems in both cases are indicators of maturity. Grasses harvested at early boot stage (when the seed head is just starting to form), have excellent fiber digestibility and energy availability, and will produce leafy hay (Figure 3). The leaf to stem ratio is also important. Leaves have more protein and digestible energy and less fiber than stems (Figure 4).


    Horses' mouth, lips and tongue, are very soft; hence, softer hay will be consumed more readily, and there will be less waste. Even though some hay may meet or pass the nutritional requirements of a horse, it also has to be attractive and edible, or it will be wasted.


    Sweet smell is attractive to people and horses, and it is also a good indication of having readily available energy (sugar). Much like soft touch, a sweet smell is an incentive for the horse to eat the hay and get its full nutritional value.


    Green is more attractive to those of us taking care of the animals, and it also is a good indication of having vitamin A. Bleached color indicates exposure to sunlight or rain and very likely oxidation of vitamin A, but other very essential nutrients are still there! Despite the color, any type of hay needs to be supplemented with an appropriate vitamin-mineral mix. Don't be too concerned about color, since weeds are also green in color.


    Reduction in hay quality due to rain is greatest after the forage is partially dried. Dry matter losses of 22% were observed when alfalfa was exposed to 1 inch of rain after 1 day of drying. Similar hay without rain damage lost only 6.3%. Sugars and fructans are water soluble, so if the hay is rained on (or soaked in water), the overall non-structural carbohydrate (i.e. sugar) content will be reduced. However, good quality, rained on hay can actually benefit horses that are sensitive to forage sugar content. Bottom line, quality, rained on hay can be fed to horses.


    Just knowing whether the hay is 1st, 2nd or 3rd crop does not predict nutrient content. The stage of maturity at which the hay was cut is the foundation of its nutritional value. Plants that grow under cooler temperatures build more digestible fiber. Therefore, 1st crop hay may have more fiber, and the fiber will be easier for the horse to digest and use.


    Horse quality hay should be baled between 13 and 17% moisture. Hay over 18% is at risk of molding, and hay baled above 25% is at risk of severe heat damage and serves as a potential fire hazard. The use of propionic acid can be used to help prevent molding of hay at time of bailing, and is usually used when the hay is between 17 to 25% moisture. Propionic acid treated hay can have a slight acidic smell, however, it is safe for horses.


    Virtually all feed has some mold spores. The presence of excessive mold if inhaled by the horse may cause coughing, heaves or allergic reactions. Horses with heaves are often particularly sensitive to mold spores or dust. Before purchasing hay, be sure to inspect the inside of at least one bale. If the hay has been stored inside and is not moldy, then the risk of it getting moldy is very low. Even though little research has been conducted on the effect of feeding moldy hay to horses, it is not recommended to feed horses moldy hay.

    Bale type

    Hay can be baled in a variety of ways, and depending on your storage and feeding methods, each type has pros and cons. Small square bales (40 to 80 lbs.) are easy to handle and store, and are a common bale type used by horse owners. Small square bales, if stored and fed properly, usually have less waste than round bales and medium or large square bales. However, small square bales can be very labor intensive. Round bales (800 to 1,200 lbs.) are also commonly used by horse owners, but because of their size, a tractor or skid loader is usually required for movement. Round bales can be less labor intensive compared to small square bales, but excessive waste can be an issue if they are stored improperly or fed without being placed in a feeder. It's also important to have enough horses (i.e. more than one) feeding off a round bale to reduce the amount of waste over time. Medium or large square bales (800 to 1,200 lbs.) have gained popularity with horse owners over the past few years, and have the same advantages and disadvantages of round bales. However, medium or large square bales tend to stack better and can be more easily "flaked" off for individual feeding compared to round bales.


    net wrapped round bale

    Figure 5. Net wrapped round bale

    twine wrapped round bale

    Figure 6. Twine wrapped round bale

    When it comes to hay storage, there are a few things horse owners can do to help guarantee their hay will stay in good condition and have minimum losses.

    1. Water/animal proof the area. If you stack hay under a leaky roof, it will grow moldier with each rain. Plug rat and mouse holes and attempt to detour larger wildlife, such as raccoons, from moving in during winter months. Not only do these animals deposit feces, but they can also chew through twine, making a mess out of your hay storage area.
    2. Do not stack hay directly on the ground. Stacking bales on pallets encourages air circulation beneath the bales and can help prevent the bales from "wicking-up" condensation from the ground. Hay bales stored on wet surfaces can have as much as 50% spoilage.
    3. Use older hay first. As long as moisture entry is completely avoided from any direction, and the hay was adequately dry when put into storage, it should keep indefinitely (Table 1). In Midwest climates, high humidity might increase moisture content and reduce storage life, so feeding hay within three years of purchase is recommended. Regardless, it's a good practice to always use older hay first.
    4. Round bales should be stored end-to-end in a "sausage" type formation to reduce waste. Stacking large round bales (on top of one another) usually increases losses, especially if they are stored outside. Stacking tends to trap moisture and limits drying from sun and wind. Studies have shown outdoor storage losses for round bales range between 5 and 35 percent depending on the amount of precipitation, storage site location, and original condition of the bale (Table 2). To help minimize this loss, buy dense bales as they will sag less and have less surface area in contact with the ground. Buy bales with plastic twine or net wrap (Figure 5) as they will resist weathering, insects, and rodents better than natural fiber twines (Figure 6). Store bales on a well drained site (if outside). Finally, never store round bales under trees or in low lying area. It is highly recommended that bales that are stored outside have some type of cover placed over them (a tarp). The outer four-inch layer of a six-foot diameter round bale contains about 25 percent of the total bale volume and is most likely to be damaged by weather if stored improperly or unprotected (Table 2). Storage losses are usually reduced by approximately two-thirds with indoor storage and by one-half with good plastic covering outdoors.
    5. Table 1. Longevity of Stored Hay
    Hay Storage Options Storage Longevity (Years) Dry Matter Loss (%)
    Conventional Shed 20 4 to 7
    Tarped on Pallet 5 4 to 7
    Net Wrap on Ground 1 15 to 25
    Twine on Ground 1 25 to 35

    Table 2. Percentage of Round Bale Volume Affected

    Bale Dimensions Depth of Weathered Layer in Inches
    2 4 6 8
    Width Diameter % of bale volume weathered
    4' 4' 16 31 44 56
    4' 5' 13 25 36 46
    5' 6' 11 21 31 40

    Hay testing

    Hay can be analyzed or tested to determine the following: moisture, protein, minerals, sugar, energy, and more. DHIA (320-352-2028), Dairyland (320-240-1737) and the Minnesota Veterinary Diagnostic laboratory (612-625-8787) can test hay for these qualities. Be sure to request an equine analysis and remember that the analysis is only as good as the sample you submit.

    Out state hay needs

    The certified noxious weed seed free forage program is designated to assure that certified forage meets the minimum standards designed to limit the spread of noxious weeds. In Minnesota, there are no areas where certified forage (hay) must be used. When trail riding and camping in public parks, it is considered voluntary to use certified hay. However, if you are planning a trail ride or camping trip with your horse on public lands in the western U.S., then certified hay must be used. For a current list of producers of certified noxious weed seed free forage in Minnesota, please call the MN Crop Improvement Association at 800-510-6242.

    Additional information

    For more information, visit the horse nutrition section of this site.

    Some information taken from University of Kentucky, Virginia Tech, University of Wisconsin, and Pennsylvania State Extension.

    Reviewers: Mike Murphy, DVM, Betsy Gilkerson, Brenda Postels and Lisa Behnken, University of Minnesota; Harland Anderson, DVM; and Ron Genrick and Abby Duncanson, Assurance Feeds.

    Permission granted for reprint of article from University of MN Extension. To read more articles from U of M Extension please visit their A to Z library >>>

  • Equine compulsive behaviors

    Written By: Margaret Duxbury, DVM, University of Minnesota

    A Cribbing Pony A Cribbing Pony

    Compulsive or 'stereotypic' behaviors are repetitive behaviors that serve no apparent function and occupy a significant portion of an animal's time. Common examples include crib biting and weaving. These problems are frustrating for horse owners. As a result, they have often been categorized as 'vices', a label that implies some fault or failing on the part of the horse. In reality, compulsive behaviors usually begin when there is something 'wrong' with the horse's environment.

    Compulsive behaviors are not seen in feral, free ranging horses. In natural settings, horses graze 16-19 hours per day consuming a wide variety of plants. They chew greater than 30,000 bites per day, walking a few steps after every bite or two. They live together in relatively stable social groups exchanging an enormous amount of social information via subtle non-verbal mechanisms including touch, smell and visual changes in body posture and facial expression.

    The horse's ability to cover long distances per day and to respond to refined social signals suits them well to our domestic needs. But it's a 'package deal'. The very same genes that enable horses to thrive on training and competition will tell them to move a certain amount per day, to forage and chew, and to form social bonds with other equines. Highly managed environments may not allow this. Some horses adapt to a restricted environment with out apparent problem. Others seem compelled to do what nature tells them—and this becomes the basis for the development of compulsive behaviors. A horse that repeatedly grabs a stationary object with its front teeth, pulls back and makes a grunting noise is said to be crib-biting.

    Horses kept in stalls with limited access to other horses, and horses fed low forage diets are more likely to crib bite. Since satiety is tied to chewing in horses, cribbing may be an attempt to satisfy a severe case of 'the munchies' brought on by having too little to chew. Horses fed high concentrate diets are also at increased risk of cribbing. In one study, foals fed concentrates after weaning developed crib biting four times as often as those that were not. High concentrate diets increase gastric acidity and the risk of ulcers—which can increase the risk colic.

    There are anecdotal reports that some horses with gastric ulcers may be more likely to crib or do things like eat dirt, however, this has not been proven in research. Equine saliva acts as a buffer to neutralize stomach acids. In horses, the sight or smell of food does not trigger salivation—but chewing does—and cribbing may too. Cribbing horses do not actually swallow air as previously believed. While owners are often concerned that one horse may learn to crib from watching another, this has not been documented, though cribbing may well arise in several horses under similar management.

    A weaving horse repeatedly shifts its neck and its weight from side to side. Weaving is often triggered in situations where the horse would like to move or follow other horses but is prevented by a barrier. The incidence of weaving in stalled horses may be decreased when horses can see and touch other horses from multiple sides.

    These behaviors serve no apparent function and occupy a significant portion of an animal's time. Treatment of compulsive behaviors can be difficult. Lack of environmental enrichment may encourage stereotypic behavior. However, ensuring a rich environment for a horse with an established problem may not be curative. What may start as a thwarted effort to accomplish a natural behavior may actually release tension for the horse. This release of tension reinforces the compulsive behavior making it more likely to occur again. The longer a compulsive behavior has been exhibited, the harder it is to treat. The behavior makes the horse feel good - and nothing we can do after the fact changes this. We can and do try, but prevention is our best tool. Devices such as anti-weaving bars and crib straps can physically prevent the horse from performing the stereotypic behavior, but do little to address the reason the horse began to weave or crib in the first place. Is it humane to simply bar the horse from behavior that may help it cope with an unsatisfactory environment? Environmental enrichment including increased foraging opportunities (offer a variety of hay types and ensure hay is available over night), adequate exercise and social interactions with other horses are important for both treatment of the problem and the welfare of the horse.

    For more information on compulsive behaviors, please contact Dr. Duxbury at

    Permission granted for reprint of article from University of MN Extension. To read more articles from U of M Extension please visit their A to Z library >>>

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