agricultural production guidelines
m
Veld in KwaZulu-Natal
Co-ordinated Extension KwaZulu-Natal Veld 3.3 1999
PLANNING A CLOSED VELD MANAGEMENT SYSTEM
K G T Camp
KwaZulu-Natal Department of Agriculture
Allocate
Camps to Each Group of Livestock
Select the Appropriate
Grazing Cycle
Plan the Period of Stay for
Each Camp
Plan the Period of
Absence for Each Camp
Determine
the Number of Camps per Group of Livestock
The Size of Camps
INTRODUCTION
The closed management system has a certain number of camps allocated on a seasonal basis to a group of livestock. The system has a fixed management pattern and possibly requires less management and experience than an open system. The planning procedure is detailed below.
ALLOCATE CAMPS TO EACH GROUP OF LIVESTOCK
- Calculate the size of each group of livestock in Animal Units (AU’s).
- Select the most suitable area of the farm for the group of livestock concerned.
- The grazing capacity of camps in the selected area should already have been established.
- Group camps together until the total area is large enough to carry the number of AU being allocated i.e. the forage requirements of the animals is matched by the forage production potential of the allotted camps.
SELECT THE APPROPRIATE GRAZING CYCLE
The appropriate grazing cycle for a given veld type (which is described in terms of Bioresource Groups) is given in Table 1.
Table 1. Grazing cycle in days for different Bioresource Groups.
Bioresource Group
Grazing cycle (days)
1 to 11, & 15
12
13, 14, 16 to 20
21 to 23
30
42
63
84
Table 2 illustrates a four camp system in Bioresource Group 8. In this example, camp 4 has been set aside as a rest camp for the season. The remaining 3 camps are grazed consecutively with a period of stay of 10 days in each camp. The grazing cycle is 30 days.
Note that planning must be based on the grazing cycle and not on the period of stay in the camps. Refer to Production Guideline 3.2 and particularly the effects of the period of stay on stocking intensity. Be aware of the danger of incorrect planning.
Table 2. The grazing cycle for a four camp system with a period of stay of 10 days in each of three camps. The fourth camp is rested for the whole of the season.
Camp No.
Period of stay (days)
1
2
3
4
10
10
10
Resting for the season
The number of grazing cycles can be estimated on a yearly and seasonal basis.
Max. cycles/year = (Grazing period in days) / ( Grazing cycle in days)
Example 1
(Bioresource Group 21) = 365/84
= 4.35 grazing cycles
Example 2
(Bioresource Group 8) = 220/30 (winter months excluded)
= 7.3 cycles for the period the animals graze the veld.
The number of grazing cycles possible in each of the different Bioresource Groups for the grazing season is given in Table 3.
Table 3. Estimated number of grazing cycles per season for the different Bioresource Groups.
Bioresource Group Number of grazing cycles per season 1 to 11, & 15
12
13, 14, 16 to 20
21 to 23
8.0
6.5
5.0
4.5
PLAN THE PERIOD OF STAY FOR EACH CAMP
The period of stay (PS) refers to the number of continuous days a herd, flock or group of livestock remains in a camp within a grazing cycle. It is essential that the PS is accurately assessed to ensure an adequate supply of quality fodder throughout the period of stay.
The number of AU which can be carried in a particular camp can be calculated from the grazing capacity (GC) of the camp (in ha/AU) and the area of the camp, as illustrated in Table 4. The period of stay is based on the number of AU that the camp can carry.
Table 4. The number of AU which can be carried in each camp of a 5-camp system, based on the grazing capacity (GC) of each camp and its area. Camp 5 is rested for the season.
Camp No.
Area (ha)
GC (ha/AU)
No. of AU
1
2
3
4
5 (rest)
20
30
40
30
50
2.0
2.5
2.8
2.0
3.1
10
12
14
15
16
Total
170 ha
67
Note that the number of AU which can be carried in a camp is calculated by dividing the area (ha) of the camp by the grazing capacity (ha/AU) of the camp.
When planning the period of stay for each camp in a camping system which includes a camp resting for a season, the total AU’s which could be carried by the grazed camps are used, that is, the number of AU’s which could be carried in the rest camp are excluded in the calculation. This is because grazing capacity is based on an estimate of the forage production potential of a camp which is derived from a veld condition assessment of the camp.
Assuming that the farm was in Bioresource Group 12 and using the formula:
(AU for camp) / (AU of grazed camps of the system) x GC
then the PS for camp 2 will be 12/51 x 42 = 10 days (Note: 51 represents the total GC of camps 1 to 4, rest camp excluded), and the PS for camp 4 will be 15/51 x 42 = 12 days.
Note that although both camps are the same size, camp 4 has a higher grazing capacity than camp 2 and can therefore support the herd for a longer period.
It should also be noted that the period of stay should not be so long that the regrowth of grass tufts grazed early in the period of stay is grazed. The rate at which regrowth occurs after the grass tuft has been defoliated varies according to the season and veld type. Table 5 indicates the recommended period of stay for veld in the different Bioresource Groups of KwaZulu-Natal.
PLAN THE PERIOD OF ABSENCE FOR EACH CAMP
The period of absence (PA) for any particular camp is the number of days a group of livestock takes to rotate through the remaining camps of the camping system during a grazing cycle. The period of absence should be long enough to accumulate sufficient fodder for the next period of stay for the camps concerned, and not too long so that the quality of herbage deteriorates.
Table 5. Recommended period of stay for the Bioresource Groups of KwaZulu-Natal.
Bioresource Groups
Period of stay (days)
1 to 11, & 15
12
13, 14, 16 to 20
21, 22 & 23
10
14
21
28
To calculate the period of absence (PA) for a camp.
PA = the sum of the periods of stay (days) of the remaining camps still to be grazed during a cycle, or
PA = the grazing cycle minus the period of stay of the camp concerned.
The recommended period of absence for the different Bioresource Groups of KwaZulu-Natal are given in Table 6.
Table 6. Recommended periods of absence for the Bioresource Groups of KwaZulu-Natal.
Bioresource Group
Period of absence (days)
1 to 11, & 15
12
13, 14, 16 to 20
21 to 23
20
28
42
56
PLAN THE PERIOD OF REST FOR EACH CAMP
This refers to an extended period during which a camp is not grazed in order for the veld to regain vigour and/or to permit seeding to occur and for new plants to become established. A rest period should be planned to meet the needs of the veld. This could mean a full season's rest, or a spring, summer or autumn rest, or a rest over a combination of seasons.
In general it can be said that sourveld, because of the short grazing cycle, will require a vigour rest every four years. In mixed and particularly sweet veld, where the period of absence can constitute a full growing cycle rest, veld should be rested according to the condition of the veld. Two important factors apply. Should veld be in poor condition, with a poor species composition and basal cover, it should receive rests as frequently as possible to improve condition. It is a decrease in the vigour of the palatable species, however, which acts as an early warning system of a deteriorating condition. It is essential, therefore, to monitor the vigour of the palatable species and here one should set a standard for vigour. A vigorous tuft will be large with many robust tillers. It will be firmly anchored in the soil by a strong root system, with no signs of erosion round the tuft. A standard can be set by familiarising oneself with veld in very good condition and inspecting grass tufts in this veld. Vigour can then be scored as a percentage of the ideal vigorous condition, 100 % representing highly vigorous veld. Veld can then be scored before and after a rest, to monitor the effects of the rest. While this is a subjective way of monitoring veld, it at least gives some idea of veld vigour, serves the purpose of improving one's observational powers and, in most cases, should allow the farmer to gain insight into the value of rest periods.
Table 7. Relationship between number of camps and periods of stay (PS) and absence (PA) with different grazing cycles.
Bioresource Groups
1 to 11, 15
12
13,14, 16 to 20
21 to 23
Grazing cycle (days)
30
42
63
84
Rest camps
Number of camps
PS
PA
PS
PA
PS
PA
PS
PA
2
3
4
4
5
6
6
7
7
8
15.0
10.0
7.5
10.0
7.5
6.0
7.5
3.5
6.0
3.5
15.0
20.0
22.5
20.0
22.5
24.0
22.5
25.0
24.0
25.0
21.0
14.0
10.5
14.0
10.5
8.4
10.5
7.0
8.4
7.0
21.0
28.0
31.5
28.0
31.5
33.6
31.5
35.0
36.0
35.0
31.5
21.0
15.8
21.0
15.8
12.6
15.8
10.5
12.6
10.5
31.5
42.0
47.2
42.0
47.2
50.4
47.2
52.5
50.4
52.5
42.0
28.0
21.0
28.0
21.0
16.8
21.0
14.0
16.8
14.0
42.0
56.0
63.0
56.0
63.0
67.2
63.0
70.0
67.2
70.0
No rest
No rest
No rest
1 Camp
1 Camp
1 Camp
2 Camps
1 Camp
2 Camps
2 Camps
DETERMINE THE NUMBER OF CAMPS PER GROUP OF LIVESTOCK
Once the primary camps have been planned for the farm, further subdivisions into secondary camps, may be required. These secondary subdivisions might be necessary for several reasons.
- The primary reason for having camps is to exercise management over the utilization of the veld and that by fencing according to areas of palatability, grazing can be controlled and areas of over and under-utilization avoided.
- Camps need to be small enough to facilitate the collection of animals for various operations. This is particularly so in veld with a low grazing capacity, i.e. a small number of animals in a large camp, or in bushveld where bush inhibits the collection of animals.
- Camps are required in order to allow rotational resting of the veld. The number of camps per group of animals depends on the frequency of resting. For example, in veld that requires a rest every four years, four camps per group of animals will be necessary.
- Camps are required to allow rotational grazing of the veld and to control the frequency and intensity of defoliation. The grazing cycle, period of stay and period of absence are manipulated to control these important management factors.
- The required number of camps on the farm varies according to the number of livestock groups and to meet the norms for rotational resting and grazing.
- If camps are too large, the unpalatable species and areas might not be utilized during the desirable period of stay (Table 5) and much of the herbage will remain unutilized at the end of the period of stay. The inference here is that the camp is too large for the size of the livestock group for the normal period of stay. This period of stay should not be extended because the most palatable grasses will be regrazed and thus lose vigour.
The number of camps per group of animals depends on inter-related management principles, that is, cycle length, period of stay and period of absence. The length of the grazing cycle must be standardised (Table 1). The periods of stay and absence will vary according to the number of camps. The objective must be to match the norms for the period of stay (Table 5) and the period of absence (Table 6).
In Table 7 the closest approximation to the norms have been indicated in bold print. Seasonal rest camps would have to be added to the number of camps per group of animals.
It can be clearly seen that three and less camps are likely to stress the veld, whereas seven or more camps per stock group provide limited advantages. The only advantage likely to be gained by seven or more camps per stock group is a greater flexibility in management, which can be of advantage when veld is in poor condition.
The formula for determining the optimum number of grazing camps is based on accommodating the desirable period of stay into the grazing cycle norm for the veld type concerned.
The necessary rest camp(s) would have to be added to the number of camps allocated to each group of animals for the grazing season. Remember, this refers to the number of camps per group of animals for optimum management and towards which one should plan. Economics will, however, dictate progress towards the ideal.
The size of camps is largely dictated by ecological factors and this will result in primary camps varying considerably in size. What is then important is that the grazing intensity or grazing days per hectare must vary according to the camp size. This is determined by varying the period of stay (within the limitations given above), based on the carrying capacity of the camp and the ideal grazing cycle for the veld type concerned.
Primary camps may often be too large for effective utilization of the veld. These camps must then be subdivided into secondary camps (see Production Guideline 2.2 of this series). The formula for determining an ideal camp size is based on the size of the group of animals, the grazing capacity of the veld and the number of camps required per group of animals.
For practical management purposes, a herd consisting of 100 AU’s is recommended. In Highland Sourveld, with a grazing capacity of 2 ha per AU, 200 ha would be required to carry the 100 AU herd. If five camps are used for this herd, with four camps to be grazed and one camp rested, the average camp size = 200/5 = 40 ha. Similarly the average camp size for all other Bioresource Groups can be estimated. In Bioresource Group 21, for example, where the grazing capacity is approximately 5 ha per AU, the 100 AU in a five-camp system would require average camp sizes of 100 ha.