agricultural production guidelines
m
Veld in KwaZulu-Natal
Co-ordinated Extension KwaZulu-Natal Veld 9.8 1999
VELD MANAGEMENT STRATEGIES FOR LIVESTOCK FARMERS IN THE SOURVELD REGIONS OF SOUTH AFRICA
K P Kirkman & A Moore
Nooitgedacht Agricultural Development Centre
P.O Box 3, Ermelo 2350, South Africa
Veld Management
Strategies
Proposed Strategies
Veld Management Basics
Mangement
Strategies for Different Scenarios
INTRODUCTION
Over the past few decades farmers have consistently experienced problems related to poor animal performance (particularly sheep) during summer on sourveld, wintering has always been difficult and is becoming increasingly costly, and scientists have established that the condition of sourveld is deteriorating. Recent literature reviews and research results indicate that traditional veld management recommendations have not provided solutions for either of these two problems.
Research results obtained over the last ten years have highlighted certain principles, which, if incorporated into grazing management, have the potential to facilitate improved animal performance, improved fodder flow (particularly in terms of wintering dry stock) and an increase in vigour of preferred veld grass species thus leading to potential veld condition improvement.
It is not the intention to provide rigid systems or recipes. The intention is to highlight important principles and outline practical guidelines, obtained from recent research, for veld management which will enable livestock farmers to produce livestock on a sustainable basis from veld. The farmers can evaluate the principles and guidelines and then decide on an appropriate strategy for their particular situations.
The main principles are:
- Any grazing has a negative effect on vigour of preferred species.
- The productivity of non-preferred species is stimulated as a result of reduced competition from preferred species with a low vigour.
- The effect of grazing on veld vigour as a whole is negative.
- Manipulation of grazing procedure (number of paddocks per herd and period in and out of paddocks) does not compensate for the effects of grazing on vigour.
- Periodic full growing-season rests are necessary to allow vigour recovery in order to maintain veld productivity at a high level and maintain the vigour of the preferred species.
- Sheep potentially have a greater negative effect on grass vigour than cattle, and thus with higher sheep numbers relative to cattle, more frequent resting is necessary.
- Sheep should preferably only graze a specific area of veld for one growing season, after which a rest, or grazing by cattle and then a rest, follows.
- Rested veld can form an important source of cheap feed during winter for dry stock with appropriate protein supplementation, and improves feed supply throughout the year. Rested veld has a higher winter value than veld which has been partially (selectively) grazed during the growing season.
- Sheep performance is enhanced if veld is burned, sheep are put on the burnt veld as early as possible and veld is kept short.
- Cattle performance is not influenced by burning or veld grass height to the same extent as that of sheep.
- Provision is made for burning veld which has rested during the previous season if necessary.
These principles highlight the following aspects of livestock production from sourveld.
- Animal performance is considered important as well as the maintenance of veld productivity and condition.
- Grazing has a detrimental effect on grass vigour.
- The main emphasis is on compensation for the detrimental effects of grazing on vigour by incorporating long term rests.
- Grazing procedure (number of paddocks per herd and period in and out of paddocks) is not considered to be of primary importance to veld condition because it has a negligible (if any) effect on compensating for vigour loss of the sward.
- Sheep and cattle are recognised as having different requirements for good performance and different effects on veld vigour.
- Sheep have a more serious detrimental effect on vigour than cattle.
- Annual grazing by sheep on the same area of veld is discouraged.
- The provision of rested veld during winter as a cheap source of roughage is considered an important means of improving feed supply through the dry winter months.
- Principles and guidelines are provided for the farmer to devise a strategy for his own situation.
(Note: The general poor quality of grass during the winter in sourveld is well recognised by farmers. Farmers may therefore be inclined to reject the idea that winter veld may provide a cheap form of over-wintering. However, the following must be considered.
- Veld rested for the growing season potentially provides a better quality of feed than veld which has been grazed during the growing season.
- Rested veld should be grazed at low stocking rates so as to provide animals with the maximum opportunity for selection.
- The animals will lose weight and condition while on rested veld.
- Animals who are provided rested veld during winter must be in good condition at the start of winter. The degree to which animals are allowed to lose weight and condition during winter will depend on their condition at the start of winter. Herd management should therefore aim to maximise animal condition during the growing season (e.g. early weaning.)
The incorporation of the principles outlined above into grazing management strategies is based firstly on the provision of adequate rests (in the form of full growing season rests) to enable preferred plants to regain vigour after a season or seasons of defoliation and thus provide for sustainable production of preferred feed, as well as maintenance or improvement of veld condition. Secondly, provision is made for satisfactory animal performance and improved fodder flow (on an economic basis). Thirdly, recommendations are based on easily understood principles, are cheap (non-capital intensive) and easy to implement.
Before outlining broad strategies for different scenarios, it is necessary to highlight two basic principles.
It must be recognised that stocking rate is of primary importance in any grazing management system and the animal intake should never exceed the production of utilisable feed in the grazing area at any period during the season. While the improvement of the vigour of the preferred grasses due to regular resting may result in higher production of palatable material, compared to a system without regular resting, it is not implied that an increase in stocking rate is possible with the incorporation of regular resting. Rather, grazing capacity of a particular farm can be estimated based on the utilisation of veld for relevant periods according to the system used, including winter utilisation of the rested veld.Stocking rate
Subdivision of veld
Veld is invariably extremely heterogeneous, with units often differing markedly from neighbouring units. The species composition, slope, aspect, rainfall, temperature, soil and many other factors may differ from one part of a farm to another, giving rise to heterogeneity. This heterogeneity is manifested in differences in palatability and acceptability of veld, both within and between species over different areas. The physical planning of veld involves the subdivision of the veld into homogeneous units and the supply and correct placing of watering points and gates. This subdivision of veld is indicated firstly to minimise area selective grazing and increase the efficiency of utilisation of homogeneous units, and secondly to provide sufficient camps for the application of animal management and veld management practises such as resting and burning.
MANAGEMENT STRATEGIES FOR DIFFERENT SCENARIOS
Four differing scenarios are presented, ranging from sheep production to cattle production with two broad combinations of varying sheep:cattle ratios between.
It has for many years been advocated that sheep should be stocked together with cattle in a ratio not exceeding 6:1, to prevent veld degradation. Little or no effort has been put into developing grazing management recommendations suitable for sheep alone. There are, however, many sourveld livestock farmers who farm with sheep alone and many who have sheep to cattle ratios wider than 6:1. This is largely due to economic reasons, as sheep production is much more profitable than beef production locally.Two block strategy
It seems that a rational approach to management of veld for sheep production would be to apply practices which favour sheep performance, i.e. burning combined with early stocking, in one season. As mentioned earlier, any grazing detrimentally affects grass vigour, whatever the system or procedure applied. A long-term rest is necessary to compensate for this vigour loss, and this can be accomplished by resting in the next season.
Such a system would logically involve dividing a farm into two blocks of comparable grazing capacity. There should normally be several camps within each block after separation of veld types. During year one, block one is burned during the late dormant season to remove residual dead herbage if necessary. The block is grazed for the duration of the growing season in a manner to facilitate satisfactory animal performance. During the dormant season, block two is available for grazing. During year two, block two is grazed during the growing season, while block one rests in preparation for winter utilisation (Figure 1).
|
Block 1 |
Block 2 |
|
|
Year 1 Growing season |
Burn Graze |
Rest |
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Year 1 Dormant season |
Graze |
|
|
Year 2 Growing season |
Rest |
Burn Graze |
|
Year 2 Dormant season |
Graze |
Figure 1. Schematic outline of two block grazing strategy.
While this strategy was originally designed for situations with sheep alone (burnt veld for animal performance and adequate rest for vigour compensation), it is in fact suitable for sheep and cattle together or cattle alone as well, particularly where shortages of cheap winter feed are a problem.
Obviously, careful fodder flow planning is required to utilise the veld optimally with a suitable class of animals at the correct time of year. For example, while rested veld with a protein supplement may be sufficient for wintering dry stock, it will be unsuitable for lactating or producing stock. Also, the period between the burning of the rested veld and its subsequent utilisation can be a critical period. Staggered burning can partially overcome this problem, but alternative cheap feed sources are usually necessary for this period. The incorporation of rested veld reduces the need for alternative feed sources to a minimum.
Three block strategy
Sheep and cattle are often stocked together in ratios wider than 6:1. A realistic management strategy for this scenario would be to divide a farm into three blocks of comparable grazing capacity. During year one, block one is burnt if necessary and grazed by sheep during the growing season in a manner to facilitate satisfactory sheep production. Block two (which was grazed by sheep during the previous season) is grazed by cattle. The defoliation of the preferred grasses in block two will be less severe than the defoliation by sheep in the previous season, as cattle graze more uniformly, and there are fewer Animal Units of cattle relative to sheep in this scenario. Block three (which was grazed by cattle in the previous season) rests during the growing season in preparation for winter grazing and a late dormant season burn if necessary. This cycle is repeated every three years (Figure 2). Although untested, it is felt that the lower sheep numbers (due to the cattle component) relative to a situation where sheep graze alone, allows the resting frequency to be relaxed from every second to every third year.It may be desirable to graze sheep and cattle together on the same block, and this can be accommodated, although currently it would seem desirable not to graze a specific block with sheep for more than one season without resting.
This strategy was designed for a scenario with more than six sheep per head of cattle, but is also suitable for lower ratios of sheep to cattle or cattle alone.
|
Block 1 |
Block 2 |
Block 3 |
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|
Year 1 Growing season |
Burn, Sheep |
Cattle |
Rest |
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Year 1 Dormant season |
Graze |
||
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Year 2 Growing season |
Cattle |
Rest |
Burn, Sheep |
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Year 2 Dormant season |
Graze |
||
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Year 3 Growing season |
Rest |
Burn, Sheep |
Cattle |
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Year 3 Dormant season |
Graze |
Figure 2. Schematic outline of three block strategy.
Four block strategy
Producers with sheep and cattle in a ratio of less than 6:1 could divide the farm or unit into four blocks of equivalent grazing capacity.During year one, block one is burnt during the late dormant season if necessary and grazed by sheep, again in a manner that will ensure satisfactory sheep performance. Block two and three are now grazed by cattle as there are relatively more cattle in this scenario. Block four is rested in preparation for winter utilisation. This cycle is repeated every four years (Figure 3).
Again, it may be desirable to graze sheep and cattle together on the same block, and this can be accommodated, although again it would seem desirable not to graze a specific block with sheep for more than one season without resting.
Careful fodder flow planning is necessary for the optimal utilisation of the veld. In the absence of supporting evidence, it is suggested that in such a scenario with relatively few or no sheep, at least one quarter of the veld should be rested annually. It may be necessary to rest more than one quarter of the veld to provide sufficient winter feed. In the crop growing areas of the sourveld, many farmers winter sheep on crop residues, and, in that case it is suggested that the rested veld be used primarily for cattle as well as for sheep during the periods before crops are harvested and after crop residues are depleted.
|
Block 1 |
Block 2 |
Block 3 |
Block 4 |
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|
Year 1 Growing season |
Burn, Sheep |
Cattle |
Cattle |
Rest |
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Year 1 Dormant season |
Graze |
|||
|
Year 2 Growing season |
Cattle |
Cattle |
Rest |
Burn, Sheep |
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Year 2 Dormant season |
Graze |
|||
|
Year 3 Growing season |
Cattle |
Rest |
Burn, Sheep |
Cattle |
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Year 3 Dormant season |
Graze |
|||
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Year 4 Growing season |
Rest |
Burn, Sheep |
Cattle |
Cattle |
|
Year 4 Dormant season |
Graze |
Figure 3. Schematic outline of four block strategy.
Cattle alone
Cattle are intrinsically more suited than sheep to the utilisation of sourveld. However, even if veld is stocked at the correct stocking rate with cattle, periodic full season rests are necessary. It has been shown that even lenient and infrequent defoliation reduces the vigour of the preferred grasses. In the absence of empirical data, it seems that a rest at least every four years is indicated to improve vigour of the preferred grasses.As a basis, enough veld should be rested to provide the required amount of winter grazing, with the constraint that at least one quarter of the veld should be rested annually on a rotational basis.
Any of the above strategies can be used for cattle alone. Cattle with the highest quality feed requirement will obviously replace the sheep in the scenarios above.
Grazing procedure within blocks - the indicator camp approach
Recent research indicates that multi-camp rotational grazing systems offer little advantage over few camp systems in terms of manipulating defoliation patterns and the periods ‘out’ in rotational grazing systems are usually too short to allow for vigour recovery. It makes sense then to manage veld within a block that is being grazed in a manner flexible enough to take advantage of seasonal fluctuations in production, and in a manner to facilitate good animal performance (keeping grass short and leafy).The so-called indicator camp system is one method of doing this. In principle one concentrates on one or more ‘indicator’ camps during the growing season. These camps are then well grazed throughout the season. Other camps within the block are only grazed when necessary, and animals are returned to indicator camps as soon as they are again ready for grazing. In this way, quality is maintained on the indicator camps by keeping them short and leafy. Also, in years of good rainfall, some camps in the grazing block may not be grazed at all or may only be grazed at a low frequency, resulting in more than the recommended area being rested. In years of poor rainfall, if all feed in the grazing block has been used, it may be necessary to move into a block designated for resting, resulting in less than the recommended area being rested. This should serve as a timely warning that there will be a shortage of winter feed, and decisions regarding stock numbers or alternative feeding strategies can be taken timeously. In the long term, if the stocking rate is correct, the correct amount of veld should be rested.
CONCLUSIONS
These strategies have been based on research results and designed to cover most scenarios in sheep and cattle farming situations in sourveld. They have been applied successfully on research farms and commercial farms. However, they are by no means the last word in veld management. For example, the ‘five cell system’ applied by a number a farmers in KwaZulu-Natal, includes most of the principles outlined above, but also formally incorporates a drought reserve, and veld in each cell rests for two consecutive years in a five year cycle.
The strategies outlined above offer the following advantages:
- Provision is made for vigour maintenance of vigour.
- Sheep grazing frequency is reduced i.e. annual grazing by sheep no longer takes place.
- Provision is made for facilitating satisfactory sheep performance.
- Provision is made for winter grazing of rested veld which has a beneficial effect on fodder flow and economics.