Brought to you by: Dr. Jenifer Nadeau


Spring has finally sprung and with the return of the robin comes
the return of green grass. If you’re like most horse owners,
you’re probably looking at your pasture with fresh eyes,
wondering what you can do to recover those bare spots, tackle
weeds, and provide the best grazing possible for your horse. By
managing horse pastures more effectively, horse managers can
increase forage production, lower production costs, improve
aesthetics, and promote a healthier environment.


The benefits of a well-managed pasture include reducing
environmental impacts of your operation, including movement of
soil and manure to water bodies, improving property aesthetics,
which makes for good neighbor relations and increases property
value, and providing feed and recreation for your horses. Using a
rotational grazing system can enhance these benefits.


For optimal health, horses need to eat about 1% of their body
weight in hay or pasture grasses and legumes daily (10 lbs of dry
matter intake for a 1,000 lb horse). Horses will generally eat
about 1-1.4 lbs of pasture grasses and legumes per hour on a dry
matter basis if they have enough pasture available. With 24-hour
access to good quality pasture, a horse grazing 17 hours each day
can consume up to 25 lbs as forage, which is enough to satisfy
his daily dry matter intake. A minimum of 8-10 hours per day on
good quality pasture would be needed to meet the dry matter
intake of 1% body weight.


Planning

Here in New England we often have restricted land space. At high
stocking density (amount of horses kept on land is high), pasture
supply will not meet the horse’s needs. Horses that weigh
1,000-2,000 lbs need a minimum of 1.75-2 acres for a mare and
foal, 1.5 –2 acres for yearlings and mature horses, and 0.5-1
acre for weanlings. With less acreage, pasture will be used
mainly for exercise since only a minimal amount of feed will be
supplied.


In planning your pasture consider animal needs and restrictions:
1) the total number of horses that will utilize the pasture, 2)
proper grass height at which to begin grazing (this is usually
about 6-8 inches), 3) the necessity of grouping horses for
turnout periods and size of each group, and 4) the desired length
of turnout periods. Next consider land resources available. Are
you lacking sufficient acreage, or are there too many acres of
pasture for the animals to keep it adequately grazed? Think about
the grass needs: 1) is there enough leaf area to intercept
sunlight for photosynthesis? 2) are rest periods long enough
following grazing to allow regrowth of leaves and to maintain a
healthy root system? 3) is proper soil pH and fertility available
to increase grass vigor and reduce weed competition? 4) is grass
protected from hooves when soil is wet?


A Rule of Thumb is to graze animals when grass is 6 to 8 inches
high. Rest grass when it is 1-1/2 to 2 inches high. Grazing
plants too short may cause horses to ingest soil resulting in
sand colic, allow more weeds to invade the pastures, increase the
chance for consumption of toxic plants and increase the need for
weed control. In the first year after seeding, never graze lower
than 4 to 6 inches, new seedings that are slow in establishing
should not be cut or grazed the first year except to control
weeds or other competing vegetation. However, a Kentucky
bluegrass and white clover pasture can be grazed beginning at 4
inches of height. Bluegrass is tolerant of shorter grazing
heights, and receiving sunshine will stimulate clover.


Seeding

Seed in early April or mid August, mid September at the latest.
August seedings are usually ideal because the soil is dry enough
to prepare a firm, well-graded seedbed and seeds germinate
quickly in warm temperatures. Root development is favored due to
slower top growth due to cool weather. Weed competition is at a
minimum and moisture is ample as fall rains become more
prevalent. Additionally you receive early use of pasture or a
full hay production season next year.


The pasture mix recommended for Connecticut is 10lb Kentucky
bluegrass, 6 lb orchardgrass and 1 lb ladino clover per acre.
Test the soil prior to planting and fertilize according to
recommendations. Fertilize after rain. Weeds and sod can be
suppressed with chemical means (2,4 D or crossbow) if desired.
Roundup kills grasses and may cause colic horses if they lick it.
Use herbicides in the cooler part of the day, not at temperatures
above 80° or on a windy day. Use when plants are blooming, in
full leaf, and actively growing. The interval between application
and grazing for 2,4 D is 7 days, there is no interval needed when
using Crossbow. Read manufacturer’s directions carefully. Do not
graze the new seeding until grass is 6 to 8 inches high.


Kentucky bluegrass has high animal acceptance, grows well in
spring and fall, is cold tolerant and is a low growing sod
forming grass that withstands overgrazing. It has low summer
production. Orchardgrass is a desirable bunch grass. It is our
highest yielding species of grass to choose from, establishes
quickly in the spring, and recovers quickly after grazing or
harvest. It produces early spring growth, and is more drought and
heat tolerant in summer than timothy. Ladino clover is a pasture
legume. Although horses generally prefer grass to legumes,
legumes enrich the diet, improve summer pasture production during
periods of midsummer heat and drought, and provide fixed nitrogen
for pasture grasses. Ladino clover may cause horses to slobber in
drought periods, but this is not a serious problem and removing
horses from the pasture will stop the slobbers. Ladino clover
requires a soil pH of 6.0-7.0 for best production/persistence.


Timothy lacks drought resistance and on very wet soil has a
shorter life. It tolerates shade poorly, grows less well than
bromegrass or orchardgrass and can easily be overgrazed. Rhode
Island bent grass is a “native” grass to this area (it is not
actually native, it came originally from Europe, Newfoundland and
the Gaspe Peninsula). It is low quality, and has few leaves. It
is adapted to acid soils and tolerates wet soil conditions and is
also drought resistant. Reed canarygrass is a coarse, tall
growing species. It doesn’t mix well with legumes, too tall and
shades legumes. It can easily be overgrazed and is drought
tolerant. Meadow and tall fescue are less tolerant than
orchardgrass or timothy. It is also traffic tolerant. If you do
decide to get tall fescue and meadow fescue, make sure you get
the endophyte free variety. The endophyte fungus causes a
thickened amniotic membrane around the foal, poor milk production
and other problems in foaling mares. Ryegrass is a grass that may
cause ryegrass staggers which leads to incoordination, tremors
and a sawhorse stance. Sorghum, sudangrass, sorghum sudan hybrids
and Johnsongrass should not be used for horse pasture. They can
cause cystitis characterized by paralysis and urinary disorders.


Introduction to Pasture

Be sure to gradually introduce horses to spring pasture. Pasture
grasses are high in sugars (sucrose, glucose, fructose and
fructan) particularly during rapid growth. These simple sugars
(sucrose, glucose, and fructose) can be digested in the small
intestine by the horse but fructans can’t be digested by enzymes
presented in horse’s small intestine, and reach the horse’s large
intestine undigested. Then it is rapidly fermented by the action
of microbial enzymes with the production of lactic acid and a
decrease in cecal pH leading to colic and laminitis. The first
day or two after the onset of pasture growth, try to limit
grazing to 30 minutes to 1 hour. Then gradually increase the time
over the next 7-10 days. Avoid grazing laminitis prone horses and
ponies on spring or lush pasture that may trigger laminitis. Use
a dry lot for overweight horses and ponies.

Good luck with your pasture
http://www.sp.uconn.edu/~jnadeau