The 1950s drought was caused by a combination of low rainfall and excessively high temperatures. In 1953, 75 percent of Texas
recorded below-average rainfall and Dallas temperatures exceeded 100 degrees on 52 days throughout that scorching summer.
The drought of 1987-1989 was the most expensive natural disaster to hit the United States until that time, with losses of
energy, water, ecosystems and agriculture estimated at $39 billion.
Scientists can give us some perspective, though, and NOAA's 2003 Paleoclimatology Perspective offers this insight: "Paleoclimatology
data suggest that droughts as severe as the 1950s drought have occurred in central North America several times a century over
the past 300 to 400 years and thus we should expect (and plan for) similar droughts in the future."
Woodhouse adds, "Even in the absence of poor land management and significant greenhouse warming, future droughts may be much
more severe and last much longer than what we have experienced this century."
While everyone should attempt to improve water conservation, land use and other factors leading to a healthier environment,
equine veterinarians will be called upon to help deal with the problem at hand – the current drought and hay shortage.
Potential problems, warning
Dust and increased particulate material are common during excessively dry weather. Horses that are somewhat affected by seasonal
pasture allergies or other forms of allergic bronchitis are likely to be even more uncomfortable under these conditions. Early
recognition, early and aggressive treatment and efforts at management are warranted.
Researchers at the University of Missouri's College of Veterinary Medicine are warning horse owners of the potential dangers
of using hay grown in other states. Because of poor hay crops in some areas, horse owners are importing hay from other states
and potentially exposing their horses to problems that are not typical with locally grown hay.
"Because of the poor Missouri hay crop," commented Dr. Philip Johnson, a University of Missouri veterinarian, "horse owners
imported hay from other states nearby and possibly fed their horses hay that was too high in selenium." Other owners may have
purchased poorer quality hay from other sources that was low in Vitamin E as well.
In June, the Georgia Department of Agriculture issued a warning to horse owners concerning problems associated with some shipments
of alfalfa hay from Michigan. These shipments contained high percentages of the contaminant weed Hoary Alyssum and 25 horses
were reported to have become ill following consumption of this hay.
According to the Agriculture and Food Department of Alberta, Canada, "weeds are exceptionally hardy and can survive and even
out-compete desirable species in drought conditions. ... Hungry horses often are more willing to eat poisonous plants if something
better is not available and some plants that are normally safe may form toxic compounds when stressed by drought."
Veterinarians should be aware of these concerns and urge clients to inspect new hay purchases, use reputable dealers and utilize
local agricultural departments for hay analysis, which usually is surprisingly inexpensive. When hay is in short supply,
the trend is to "take what one can get," but equine digestive problems or worse quickly make bargain hay no bargain at all.
Many horse owners will be looking for alternative hay sources and equine veterinarians should be able to offer some scientifically
Ideally, horses should receive 1.5 percent to 2 percent of their body weight daily in the form of roughage, which is by definition
high in fiber (minimum of 18 percent crude fiber). A minimum of 1 percent roughage is required to maintain normal digestive
function. Lower fiber sources (11 percent to 15 percent) can serve as alternatives during droughts and will not replace but
can reduce the amount of hay that must be fed.
Hay cubes sometimes are used to supplement roughage. These small cubes are made of alfalfa, grass hay or other hay sources
and are a nice alternative to hay. Alfalfa cubes can replace alfalfa on an equal-weight basis or replace grass hay on a ratio
of a little less than one-pound cubes to two pounds of grass.