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Extension > Horse Extension - Ask an Expert > April 2015

Monday, April 6, 2015

Crown Rust in Oat Hay

Question: The cover crop of oat in my newly seeding alfalfa hay field has rust. The oat will get cut and baled with the alfalfa, and I'm wondering if this is going to be a problem for the horses?

 Response: Crown rust is a fungus that affects the leaves of oat, and spreads from leaf to leaf via spores. There are some varieties of oat that are more resistant to crown rust than others. 
Crown rust on oat should not pose a major health risk to your horses once baled. However, crown rust will likely decrease the nutrient value of the hay (decreased protein and digestible energy levels) and may decrease the palatability (the horses willingness to ingest the hay) of the hay. Therefore, it is recommended that you test the hay for forage quality and supplement with a vitamin/mineral mix or concentrate as needed. 

More importantly, crown rust may make the hay dusty, which could lead to respiratory issues. Feeding the hay outdoors and pulling apart the flakes prior to feeding may help to decrease the dust level. Wetting (not soaking) the hay with water prior to feeding will also help reduce the chance the horse will inhale the dust and spore particles. 

 Author: Krishona Martinson, PhD, University of Minnesota  


Hay Consumption

Question: How many square bales does a horse eat a day. Is it necessary to have hay/feed in front of a horse all day.
Answer: It is difficult to estimate how many small square-bales of hay a horse needs each day since bales vary in size and weight. Its better to feed based on weight. The average adult horse required about 2% of its bodyweight in feed (hay plus grain) each day. For example, a 1,000 adult horse at maintenance would require 20 pounds of feed daily. If your small square-bale weighs 40 pounds, then the horse should be fed half the bale each day. If the bale weighs 80 pounds, then one quarter of the bale would be required each day.                 

If you are feeding grain, then subtract that amount from the hay meal. For example, if you are feeding 5 pounds of grain, then reduce the amount of hay fed by 5 pounds. Using the above example, the hay ration would then be reduced from 20 to 15 pounds. Adding the 5 pounds of grain to the 15 pounds of hay fed daily would help ensure the horse was receiving 2% of their bodyweight in feed each day. It is also a good idea to assess horse body condition each month and adjust the amount of hay (and grain) fed as needed.                      

 It is not necessary for horses to have feed in front of them all day. In fact, this practice can lead to obesity if high quality, energy dense feed is offered without sufficient exercise. Feeding 2 to 4 small meals throughout the day, that equal 2% bodyweight, is ideal since horses evolved to consume several small meals throughout the day. However, feeding more than two meals throughout the day is not feasible for many horse owners. One management method that has proven to extend foraging time while allowing horses to remain on a controlled diet in the use of slow feed hay nets. A recent study at the University of Minnesota found that horses took 3.2 hours to consume a hay meal when fed off the stall floor and 6.5 hours to consume the same hay meal when fed from a slow-feed hay net. Researchers concluded that slow-feed hay nets represent simple and affordable management tools for extending foraging time when meal feeding horses. For more information on the hay net study, click here.

 By: Krishona Martinson, PhD, University of Minnesota

Trees to Plant in a Horse Pasture

Question: Our horses pasture is along a residential road. In attempts to filter out the exhaust, we are proposing to plant shrubs/trees along the inside of our fence. The city requires these plantings to be on "our side" of the fence. What trees/shrubs are "safe" for horses, in case their curiosity results in a nibble?

Answer: It is more practical to provide a list of trees that should not be planted and why. Do not plant:

Plants in the cherry family (Prunus species). For example, chokecherry, most parts of the plant contain cyanide which causes death if ingested. Black cherry is a common food source of eastern tent caterpillars which are associated with Mare Reproductive Loss Syndrome.    

Ornamental shrubs including rhododendron, Japanese yew, and oleander. These ornamental shrubs will cause death when ingested in small amounts.     

Be cautious when planting the following trees:

Oak. New buds and green acorns hulls contain tannins. Ingesting large amounts for more than a few days can lead to diarrhea, colic, swelling, and frequent urination.

Maple. Ingestion of 1 to 3 pound of dried or wilted leave (not fresh leaves) can cause toxicity. Signs include red/brown urine, depression, and possibly death.  

Female boxelder trees. Seeds may contain a toxin that is known to cause seasonal pasture myopathy. Male trees do not produce seeds.

Oak, maple and boxelder trees are common in horse pastures. They can be planted, but owners should be aware of the potential issues. The only way to ensure the horse will not ingest parts of the tree is to fence the horse out of the trees. Most horses who are well fed will rarely seek out ‘alternative’ food sources like trees. 

By: Krishona Martinson, PhD, University of Minnesota

Hay Soaking

Questions: Should I always be soaking my horse's hay, or is this something reserved for horses with respiratory problems or other health conditions such as laminitis?

 Answer: Soaking hay in water is a common strategy used to manage horses diagnosed with laminitis, equine metabolic syndrome (EMS), polysaccharide storage myopathy (PSSM), and hyperkalemic and periodic paralysis (HYPP). Soaking hay should not be done, and is not necessary, for healthy horses because essential nutrient are leached during the hay soaking process.

 Hay is soaked for horses diagnosed with PSSM, EMS and laminitis to remove some of the nonstructural carbohydrates (NSC) from the forage; NSC are water soluble. Horses diagnosed with PSSM should have an overall diet of ≤10% NSC, and horses diagnosed with EMS and/or laminitis should have an overall diet of ≤ 12% NSC. Although forage is the major component of a horses diet, when feeding horses diagnosed with these diseases, make sure to account for NSC content in any grain, supplements, and treats the horse is also receiving.

Before soaking hay, it is critical to have the hay tested for nutritive value. Legumes (i.e. alfalfa) tend to be lower in NSC compared to cool-season grasses (i.e. timothy), and hays containing legumes may not need to be soaked. Soaking most grass hays for 15 to 30 minutes will remove enough NSC for horses diagnosed with PSSM, EMS, and/or laminitis. However, testing forage both before and after soaking is necessary to ensure recommended levels of NSC are being met. Soaking forage for greater than 60 minutes is rarely necessary and may actually be detrimental due to excessive leaching of essential nutrients and loss of dry matter.

 For horses diagnosed with HYPP, soaking hay is water is necessary to leach potassium (K), which is water soluble. Unfortunately, legumes and cool-season grasses tend to be very high in K and often exceed the recommended 1.1% maximum over-all diet for horses diagnosed with HYPP. For horses with HYPP, soaking hay for 60 minutes is often necessary. If soaking hay for 60 minutes does not achieve the recommended amounts, owners may need to consider feeding a complete feed that formulated for horses diagnosed with HYPP.

 For horses diagnosed with respiratory disease, including heaves, thoroughly wetting the hay is sufficient. Wetting the hay is different from hay soaking. The goal of wetting hay is to weigh down
mold and dust particles so they are not inhaled. Horses diagnosed with respiratory problems do not have nutrient restrictions (unless they have a secondary diagnosis), and therefore, hay soaking is not necessary. Wetting the hay will have a minimal impact on leaching of essential nutrients.          

Bottom line, hay soaking should only be done if the horse has been diagnosed with laminitis, EMS, PSSM, and/or HYPP, and a hay analysis indicates specific nutrients are in excess of recommendations. Thoroughly wetting the hay is necessary for horses diagnosed with respiratory disease. Soaking hay in water is not necessary for healthy horses. For more information on hay soaking, click here.

 By: Krishona Martinson, PhD, University of Minnesota


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