PASTURE MANAGEMENT at the PENN STATE HORSE BARNS
By Sarah Thomas
Introduction
Pasture management is
essential in order to keep a safe and healthy environment for horses. With
over 50 horses at the Penn
State horse barns
spending most of their time outside, pasture management becomes crucial in
order to supply the horses with an adequate nutritional source of
forages. There are many options for
pasture management and Penn
State uses a few of
them. Three aspects of pasture
management that will be discussed in this document are grazing management,
weed control, and parasite control. The
techniques that Penn State
uses as well as suggested techniques for both Penn
State and other horse
farms are described below. Please
note that all of the horse pastures at Penn
State are not mentioned
in this document and also that there are more aspects of pasture management
than those below.
Grazing Management
Stocking Density
The general rule for the
amount of horses on a pasture is to allow at least 1.5 acres per horse
(Pickeral 2003). However, when horses
are using the pasture as a primary nutritional source, as many of the Penn
State horses do, it is
suggested that 2-3 acres per horse should be allowed (Russel 1999). Supplying 2 acres per horse at Penn
State would entail
having over 100 acres of pasture space just for the horse barns. Although this would be nice, it is not
presently feasible. To give an
example of stocking densities at Penn
State, a few of the main
pastures will be evaluated.
In an average year at Penn
State, there are 12
broodmares and 10 foals. They are
kept on a 16-acre pasture directly behind the barn as seen in Figure 2. The stocking density of this pasture is
0.94 acres per horse (each foal counts as ½ a horse), which is well below the
suggested 2 acres per horse, from spring until late summer when the foals are
weaned. At weaning time, one older
mare is left with the 10 weanlings on that pasture (stocking density = 1.45
acres/horse) until November when the mares return and the foals are moved out
(stocking density = 1.3 acre/horse).
So from late summer until early spring, the stocking density is nearly
adequate (not taking into account the poorer production in the pasture given
the winter season). During the time
of weaning, the mares are moved to a 5-acre pasture, which leaves the mares
with about 0.5 acres per horse.
Despite the high number of horses per acre in these pastures at
different times during the year, the grass grows relatively well and does not
present a problem nutritionally for Penn
State. Hay and grain are supplemented as needed
according to pasture growth and season of the year.
As for the 2-year old
pasture, there is only about 0.25 acres per horse and as a consequence there
is very little grass and a lot of dirt and weeds. From November through May, about 10 2-year olds are on this
pasture. While from June through
October there are fewer horses on the pasture, there is still no resting
period for grass to re-grow. The lack
of grass in this pasture is not a problem because the purpose of it is to
provide the horses with a place to exercise and it is not used as a
nutritional source of forage. The
2-year olds are only on the pasture from about 9 am until 4 pm and they are
given full feed to meet all nutritional requirements.
The figure above shows 4
different paddocks for Penn
State horses. In the middle, there is a 1-acre lot where
the 10 yearlings are turned out during the weekdays from November through May
(stocking density = 0.1 acre/horse). There
are also 3 other plots of 1 acre, 0.5 acres, and 0.3 acres that are used for
the stallions. All of the lots in
this area are mostly dirt and weeds and do not supply much nutritional value
for the horses so hay and concentrate must be supplemented.
As seen in the pictures
and based upon calculated stocking density, the pastures at Penn State are in
desperate need of rotation to keep the horses off of the pastures for periods
of time. It is recommended to keep
pastures free of horses for about 4 weeks at a time (Russel 1999), but due to
lack of acreage, Penn
State cannot do this.
Weed Control
Mowing
One way to control weeds
is by mowing the pastures regularly. Penn
State has a variable
mowing schedule, meaning the pastures might only be mowed when the weeds are
already too high. Mowing will also
help to keep the grass young and palatable for the horses (Russel 1999). Regular mowing also helps the grass to
grow more densely (Pickeral 203).
Fertilizing and
Liming
Fertilizing and liming are
important for controlling weeds and encouraging better grass growth. Penn
State uses urea, a
source of nitrogen, on all of the pastures, except for the dry lots, once a
year. A more ideal approach to
fertilizing would be to have soil tests done in order to determine the amount
of fertilizer needed and if liming is necessary. Liming helps to reduce the acidity of the soil.
A recommended fertilizing
schedule is to use ½ of the yearly recommended dose of nitrogen )determined by
a soil test) in early spring, ¼ after late spring, and ¼ at the very end of
the summer. This schedule helps to
accommodate different types of grasses that may be growing in the pastures
(Russel 1999). It is important to
leave horses off of the pastures until the fertilizer is washed into the soil
(Pickeral 2003). At Penn
State, the urea that is
used soaks into the soil just by the morning dew, so the horses only have to
stay off of the pasture for a day or two.
Dragging
Dragging fields with a
chain harrow serves two purposes: weed control and parasite control. The role dragging has in parasite control
will be described later. Penn
State does not drag the fields
regularly, however, dragging is used at Penn
State to clean up left
over hay that has been fed over the winter.
Dragging for weed control is important to spread manure and pull up
dead forage in order to allow for young grass to grow (Pickeral 2003).
Parasite Control
McMaster Fecal Egg Counts
Each month at Penn
State, a McMaster Fecal
Egg Count is performed on 30-40% of each group of horses. This allows for appropriate worming when
needed. Through these tests, it has
been discovered that the parasites at Penn
State appear to be
developing a resistance to fenbendazole, a common de-wormer. This information has proven extremely
valuable so alternative de-wormers could be used. The McMaster Fecal Egg Count is a helpful technique that is
simple enough for a farm of any size to use, either on the property or by
sending fecal samples to a lab or to the veterinarian.
Dragging
As mentioned before,
dragging can also help with internal parasite control. Dragging the fields with a chain harrow
spreads the manure out so that the gastrointestinal parasites are killed by
the sunlight, dry air, and cold (Russel 1999). However this procedure is controversial and may in fact
increase the pasture parasite burden if done during temperate, moist weather.
Other Options
for Maintaining Pastures
Sometimes pastures become too
full of weeds with too little grass and no nutritional value for the horses,
as some of the Penn
State pastures have
become. There are two methods for
converting pastures back to nutritional sources of forage, although they are
quite expensive. The two methods are
“renovating” and “re-establishing” (Russel 1999).
Renovating
Renovating is just
management of the pastures based on the concepts described above. Basically it is the control of weeds by
herbicides and mowing, liming and fertilizing (based on soil tests), reducing
the vigor of sod, and reseeding into the sod a legume or legume-grass mixture
(Russel 1999). Although this
treatment is expensive, if done correctly, it can rejuvenate a pasture.
Re-establishing
Re-establishing is done by
completely destroying all existing vegetation in the pastures, putting down
fertilizer and lime on the soil, and preparing a seed bed that is planted
with appropriate forages. Although
this method is more expensive than renovating, there is a higher yield in
grass growth and it will provide an excellent nutritional source for the
horses. This method is especially
useful on pastures that are similar to some of Penn
State’s with a lot of
bare ground and weeds. However, it
is critical in both these procedures to keep horses off of the pastures for
extended periods of time. Like at Penn
State, this option is
not often available on the average farm.
Conclusion
The proper management of
pastures can eventually reduce costs for a farm by providing an adequate
nutritional source of forages for horses.
The horse pastures at Penn
State could benefit from
more maintenance, specifically greater pasture rotation, but the amount of
horses and a limited amount of space prevents many of the management
techniques just described. However,
despite this, the Penn
State horses do receive
proper nutrition to allow for good body weight, production, and general
health. The groups of horses that
require optimal nutrients from the pastures (i.e. the lactating mares and the
yearlings) are on pastures that grow well and provide a good nutritional
source of forage. For more
information regarding the techniques described above as well as other pasture
management techniques, please see the references below for further reading.
References
Pickeral ,Tamsin.
“Grass-kept Horses.” The
Encyclopedia of Horses and Ponies. Parragon Publishing,
United Kingdom. 2003.
pp. 36-39.
Russel, Mark A.
“Pastures for Horses.” The
Horse Industry Handbook. American
Youth Horse Council, Colorado. 1999.
Sec. 730.
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