Caution with Summer Pastures for Horses
Horses are herbivores and need forage in their diet either as
pasture or hay. But not all forages are suitable for horses.
A favorite meal for horses anytime is high-quality pasture,
but that can be a problem in late summer. Hot, dry weather
typically causes a slump in summer pastures. The situation occurs
so frequently that some horse owners plant a temporary summer
In fact, one of the mainstay summer forages for cattle is hybrid
sorghums, which horses shouldn't graze.
Hybrid sorghums, Sudan grass and johnsongrass are related. When a
horse grazes these forages cystitis can result. Cystitis is an
inflammation of the bladder.
With cystitis horses may dribble urine, causing skin scalding.
They may also be uncoordinated in their hindlegs, especially when
backed or turned, causing them to sit on their hindquarters like
a dog. Some have reported that mares may abort when grazing these
What other options do horse owners have for summer annuals? The
millets are also often used for summer grazing.
But German and foxtail millets also may cause problems with
horses. If a major part of the diet, they may act as a laxative,
cause excessive urination and kidney and bone problems.
The major summer annual for horses is pearl millet. But don't let
horses graze it until it's 10-12 inches high. Stop them from
grazing when it's taller than 24-36 inches. Also don't let them
graze it closer than 5-6 inches. Its best use is with a
high-stocking rate and rotational grazing.
If summer pastures become dry, horses on pasture may have to be
supplemented with hay. This can cause another problem if hay is
in short supply or expensive. Normally you would conserve hay
until the winter when there isn't much pasture.
Brown, dry summer pasture does have some nutritional value. But
if owners don't use good pasture management, horses may easily
overgraze it, resulting in loss of forages.
So you may want to feed horses grain in some situations. Grain
supplements the decreased nutritive value of summer pasture and
conserves the winter hay supply.
Owners can evaluate summer pasture by body-condition scoring
(BCS) horses. The BCS is a visual, hands-on evaluation of
body-fat content and is a method to evaluate the energy intake of
BCS will be more reliable when several horses are evaluated
monthly on pasture. You should have started scoring your horses
before the dry summer began.
If the average BCS of three or more horses decreases, your
pasture isn't providing adequate energy. So feed grain or hay to
correct this situation.
Whatever you do, if your summer pasture decreases, don't let your
horses graze hybrid sorghum forages.
Source: Dr. Frederick Harper
UT Agricultural Extension Service