Agriculture Reference
In-Depth Information
Table 10.2
Grazing effi ciency or utilization rate.
Relation of Gain per Hectare and Average Daily Gain at
Different Stocking Rates
Grazing Effi ciency
includes
Maintaining
Minimum Stubble
Approximate
Days on Each
Paddock
600
Number of
Paddocks
500
400
Continuous
—
40% or less
or (80%
overgrazed, low
yield)
Gain/hectare
ADG
300
200
4 to 6 paddocks
7 to 9 days
40 to 55%
100
8 to 10 paddocks
4 day
55 to 65%
0
24 to 45 paddocks
1 day or less
70 to 80%
8
10.4
13.6
16.4
Hay
—
70 to 80%
Goats per Hectare
Source: Brann, 2005 .
Figure 10.2
Average daily gain and gain per
hectare for goats grazing continuously annual
ryegrass pastures at different stocking rates.
Source: Solaiman et al., 2006.
tures. The timing of animal rotation is based on the growth
characteristic of the forage in the pasture and occasionally
may depend upon the stage of the parasite cycle prevailing
in that environment.
The size of the paddocks dictates the need for fencing
and the design of the water supply system. Paddock size
is positively correlated with animal numbers, animal size,
level of intake, and days on pasture, but negatively cor-
related with available forage and grazing effi ciency. The
equation below can be used to determine paddock size for
a rotational grazing system.
produce the maximum gain per hectare. Higher stocking
rates often will reduce average daily gain (ADG) even
though gain per hectare will be increased as illustrated in
Figure 10.2 (Solaiman et al., 2006 ).
Because investments in fencing and watering systems
are small with continuous grazing, it is not capital inten-
sive and requires few management decisions because
animals are not moved from pasture to pasture. Research
data on optimum stocking rates for pastures continuously
grazed by goats are lacking, and most of the available
information has been transferred to goats using cattle data
considering that fi ve or six goats are equal to one animal
unit. However, parasite management is diffi cult with con-
tinuous grazing systems and warrants further investigation.
Also, forage preferences and accumulation of undesirable
plant species may be greater with goats than cattle due to
greater plant selectivity by goats.
(
No. Anim.
) × (
Anim. Wt.
)×
(
DMI, % BW
f Rotation
cm of forage kg per ha, cm
DM from grain m
) × (
Freq.o
)
Hectare Paddock
=
(
)
×
(
)
−
⎡
⎢
⎤
⎥
(
)
ix
×
(
)
%
GE
Where, DMI = dry matter intake; BW = body weight;
GE = grazing effi ciency.
Dry matter intake for goats on pasture will range from
3.5-4% of body weight. If grain supplement is provided
on pasture, dry matter contributed from grain mix can be
deducted from total forage DM required. Frequency of
rotation (days on paddock) is a managerial decision, but
grazing for 3-7 days per pasture usually is recommended.
Grazing effi ciency (utilization rate) of pasture varies
depending on number of paddocks used and height of
grazed forage (Table 10.2). The recommended grazing
height and rest days for pasture are listed in Table 10.3.
For goats, it is highly recommended to move goats out of
pasture when vegetation height approaches 13 cm (5 in.).
Rotational Grazing
Rotational grazing or controlled grazing is an economical
way to provide forage for goats, but this system requires
careful planning, fencing, and more intensive animal and
pasture management. This also is called management-
intensive grazing where goats are allowed to rigorously
graze one pasture before being rotated or transferred to
another similar pasture. Rotational grazing permits plants
to regrow on the grazed pasture and is helpful for parasite
management. With this system, multiple paddocks are
needed so that grazing animals can be rotated among pas-
