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HEALTH CONCERNS IN HAY
Also consider potential dangers lurking in forage materials. Blister beetles are a deadly component of legume hay – a very small amount (3-6 beetles) is lethal if consumed
by a horse. Beetles present in hay fields
may be killed during harvest, ending up in some bales. Blister beetle problems are less likely encountered in spring or early summer first-cutting hay since they are attracted to flowering plants that often coincide with late summer cuts of alfalfa. Blister beetles also feed on grasshopper larvae, with increased risk of their presence during abundant grasshopper years.
Another concerning health problem arises from ingestion of spores of the botulism bacterium. While not as common in hay
as with ensiled feeds, botulism is usually associated with the presence of dead animals caught up in hay during baling. It also occurs from ingestion of contaminated soil baled with trampled forage. An environment conducive to botulin bacteria also promotes mold growth, yet another reason not to feed moldy hay.
Haylage or silage is particularly at risk
of botulism due to processing that couples high moisture and anaerobic fermentation, an environment that encourages proliferation of Clostridium botulinum bacteria. Mold- contaminated or discolored haylage should not be fed. Carefully inspect hay before feeding and discard suspect material. Round bales are more difficult to inspect, but when horses have adequate forage, they tend to eat around bad hay due to poor palatability.
STORAGE OF GRAINS AND SUPPLEMENTS
Whether storing forage or grain-based feeds, moisture is the enemy to horse
health. Lessen the risks of deterioration and mold by keeping supplements in cool, dry environments, with containers tightly closed to exclude moisture, insects or rodents. Oxidation (air exposure) affects short-lived vitamins, particularly B-vitamins like biotin.
High humidity or moisture in cereal
grains can lead to mycotoxin production with dangerous health consequences to horses. Various mycotoxins are produced from fungi present at grain harvest that proliferate in
the presence of moisture or humidity during storage. Very small amounts of mycotoxins won’t usually affect a horse. With significant mycotoxin levels, reduction in feed intake may be the first sign of a problem. Often, fungi
are neither visible to the eye nor with a black light – some corn kernels may have a pinkish, reddish hue, but not always. For accurate
identification of mycotoxins, a sample must be submitted to a lab for testing.
A horse consuming moldy corn is
at risk of developing liver failure and a serious neurologic condition called equine leukoencephalomalacia (ELEM or moldy corn poisoning) caused by fumonsin from Fusarium moniliforme. During years of questionable corn harvests during wet weather, corn concentrations in grain are best kept less than 20% and the corn heated through steaming, pelleting or extrusion.
All grains are subject to mold and development of mycotoxin, not just corn. The fungi Aspergillus produces alfatoxins in cereal grains – at high levels, these are detrimental to horse health.
STORAGE LONGEVITY OF GRAINS
Feed companies generally designate
an expiration date within 30-60 days
from manufacture of grain products. If maintained under ideal circumstances,
feed may remain safe for 4-6 months, with straight whole grains potentially lasting years. Ideal conditions depend on low moisture (less than 13%), a minimum of broken kernels, and restricted infestation
by insects or rodents. Shelf life is affected by humidity and temperature of storage facilities at both the warehouse and farm, degree of infestation of rodents or insects, and exposure to air. It helps to store bags
on pallets and stack them no more than five high, especially in humid climates. Sealed bags last longer than open bags since once
a bag is open, degradation begins from exposure to air, humidity and heat.
Addition of molasses and/or oil to grain mixes increases moisture and can affect shelf life. High-fat feeds are more prone to rapid spoilage from oxidation (rancidity) that degrades fats and fat-soluble vitamins. While manufacturers may add preservatives to slow oxidation, mold and bacterial growth, this doesn’t totally prevent deterioration, which
is determined by storage conditions. Rising temperature and humidity during summer months decreases storage life of feed. It’s best to keep on hand only as much grain as can be
So that air circulates freely to facilitate evaporation of moisture, stack square bales on edge, leaving narrow gaps between rows, alternating bale orientation in each layer and stacking no more than 4-5 bales high.
A couple of health concerns to watch for with the storage of hay are:
Mold Contamination
VETERINARY VIEWS
Even under ideal storage conditions, more than 5% of vitamins in hay are lost each month after it has been cut.
Blister Beetles
SPEEDHORSE August 2020 109