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Last update: November 17, 2010 12:28:05 PM
D Furstenburg
Agricultural Research Council : Range & Forage Institute,
Grootfontein Agricultural Development Institute,Private Bag X 529, MIDDELBURG. 5900
Abstract
Changes in the socio-economic environment in southern Africa have lead to a change from livestock to integrated game farming, resulting in a rapidly expanding game industry. The present higher game production, risk saturating present forms of marketing. Consequently a struggle for survival by the “smaller”, marginally profitable game farmer develops. A 10-year study conducted from 1990 to 2000, of integrated game/livestock production systems in the Valley Bushveld of the eastern Cape revealed a strategy and means to optimize game production. Population performance by individual game species can be raised by as much as 20% by the manipulation of natural population dynamics through: a) management of individual species needs, b) annual control of age and sexual structures, c) filling all the potential niches in all habitats and, d) selecting the best performing game species. Focussing on management of game production, for high annual yields and for specific pre-defined markets, has become the key to the future survival of the “smaller” landowner.
Introduction
Game production is poorly understood, but has become the key to sustainability and the survival of the majority of present day game farmers. A definite distinction is to be made between game production farming i.e. implementing livestock farming principles to fit the natural limitations of individual game species and game ranching i.e. managing ecological biodiversity and game conservation.
The game industry, in contrast to pure conservation, implemented the agriculturally defined Large Stock Unit (LSU) as benchmark to determine carrying capacities and game stocking rates to optimize financial returns. Applying this principle does not fit the needs of game, nor the co-existence and functioning of multi-species assemblages in an eco-system, consequently misconceptions about the production of game evolved. This resulted in degradation of the natural resources and non-viable economic returns. A game production optimization strategy was developed after a 10-year study (Furstenburg Undated) of integrated game/livestock production in the Succulent Valley Bushveld in the eastern Cape. Confusion has arisen regarding the risk of the eco-tourism and trophy market mat being pulled from under the feet of the “smaller” game farmer. This is largely due to the development of a series of greater wilderness- and transfrontier parks across southern Africa (Peace Parks Foundation 2001).
This scenario is aggravated by a rapid increase in the number of landowners entering the game industry, eg. a 42% and 48% increase in 1999 and 2000 respectively in the eastern Cape alone. New markets and products need to be developed (Hugo 2000 and Laubsher 2000) to safeguard and secure the industry from a sudden collapse in the near future.
Background
Present South African socio-economic environment
The number of game ranches, eco-tourism, conservation and game farms, conservancies and production systems in South Africa exceeds 9 000 in number at present, covering more than 13% of the country’s total land area (Falkena & Van Hoven 2000). National and provincial parks cover an additional 5%. It has been estimated that some 3 000 additional livestock farms, less than 4 000 ha in size with 80% less than 2 500 ha in size, were in a process of partial or full conversion to integrated game/livestock production. Vague estimates gleaned from the eastern Cape alone, indicate that 25-30% of all livestock farms have already integrated some form of game production which is not included in the statistics quoted above. This trend is both terrifying and alarming, taking into consideration that all the game farms compete for the same market. Most privately owned land units have become too small to sustain the animal numbers needed to be economically viable at the natural reproduction rates of the game animals. They therefore operate on the meagre profits gleaned from professional hunting and eco-tourism, with accommodation and hosting, rendering the bulk of the income. Many ranches merely survive by subsidies received from external commercial businesses other than the game industry.
Main trends responsible for the present status of the socio-economic environment (Falkena & Van Hoven 2000):
Deregulation of the farming sector by the World Trade Organization followed by the local government forcing the agricultural sector to improve productivity and become less dependent on government support;
Loss of political leverage – Agriculture has lost its political clout in parliament by the changes in voting power in the rural areas – agricultural subsidies disappeared, production costs increased and commodity prices came under severe pressure from international competition – marginally profitable farming operations being forced out of business;
Climate – 60% of South Africa receive less than 500 mm rain annually, which is regarded internationally as being semi-desert and 21% less than 200 mm which is regarded as desert – at best, maize production in SA may reach 2,3 tons/ha compared to 7,9 tons in the USA, and livestock carrying capacity in SA may reach 4 ha/LSU compared to 1,5 ha/LSU in New Zealand – the arid nature of the South African climate makes it difficult to compete with the World Market;
New labour legislation enforced by law, rapidly increased labour cost, decreased productivity and therefore lead to a decline in profitability;
The increase in AIDS and malaria, especially in rural areas, results in a declining productive labour force – which also have a negative impact on foreign eco-tourists and hunters visiting the country;
Stock theft – since the death penalty and hard labour had been abandoned in SA prisons, law and order took a turn for the worse – enhanced by unemployment, poverty and illegal immigration – the loss of income due to livestock being stolen, the high cost of increased policing and security and the exclusion of large portions of land in high risk theft areas from production – are all factors contributing to livestock farming becoming less profitable and less viable.
Rapid transformation of marginally profitable livestock production systems into game ranching and/or game production farming seems to be the only ultimate solution in the short-term. However, this is not a simple solution. Limitations set by land size and habitat requirements, spatial separation and interaction, social behavioural needs and the performance potential of game species are subjects poorly understood at present by both the landowner and the scientist. Exacerbating the situation, is the poor understanding of the differences in production principles governing livestock and game and, the extent to which game can be manipulated to increase and optimize production. Complicating the matter of transformation, is the future risk of instability of the present game produce markets, the need to develop alternative markets (Laubsher 2000) and the potential to develop alternative or new products (Hugo 2000).
Of immediate concern at present is the impact that the development of the eight large transfrontier parks in southern Africa (Peace Parks Foundation 2001), as well as various large over 100 000 ha in size wilderness parks e.g. Greater Addo; Cape Peninsula; Baviaanskloof; Oudtshoorn; Lake St Lucia; developments in northern Angola; etc., will have on eco-tourism and trophy hunting. Especially the effects of competition upon a) the “smaller” landowner with less than 4000 ha and b) the integrated game/livestock farmer, who is not capable of creating the Great African “Experience” Atmosphere, but who still depends for survival upon profits derived from game. Currently, 85% of all of Africa’s trophy exports derive from South Africa (Falkena & Van Hoven 2000), what would it be like in 10-15 years time? From the total income from game ranching, 80% derives from hunting, 10% from eco-tourism and venison export and 10% from live sales (Falkena & Van Hoven 2000). The question could rightly be asked, where does the “smaller” game farmer fit in with regard to the limitations set by the spatial needs of the game species when it comes to the viability of trophy and/or venison production?
The origin of game animal production
Diversification and differentiation owing to the needs of the living, had its origins in prehistory. Evolutionary changes in the development of different living creatures, was the outcome of two major events: a) changes in existing environments and habitats and b) differences which developed in the spatial needs of different groups of animals and plants. Man has developed the skills and technology necessary to enable him to overcome extremely poor environmental conditions. The environment can be changed to suit his needs. Livestock has been domesticated by man since about 4000 years BC, for increased performance, primarily for quantity and secondly quality. This enabled one male to mate with up to 40 or more females, which is in direct conflict with their natural social and spatial needs. The outcome of this domestication is, the achievement of continuous, maximum reproduction under the prevailing conditions of an adequate, high quality, forage supply. The abundance of forage became the major factor affecting livestock production.
The natural law, “survival of the fittest”, still applies to all non-domesticated animals, irrespective of: a) the management system being followed, b) land size, c) species composition, or d) degree of integration with livestock. Game still have their natural instincts and requirements and therefore restrict their production to the limitations associated with confined, fenced-in, areas. Nature’s Law laid down that only the strongest males will mate. The weaker and younger, get driven away by the stronger. Often females refuse to mate with the weaker males, because through instinct they seek out the strongest genes to be carried forward in their offspring. Consequently, with too many males around, the dominant males spend more time in securing females, than in mating, therefore rarely reaching their potential mating limit. Reducing male numbers in favour of females, does not necessarily mean a counterbalanced increase in production and population growth. Game management is therefore, highly complex (refer to Table 1).
Discussion of principles governing production
Game production is governed by the various parameters most limiting with regard to the landunit and habitat (Furstenburg Undated):
Suitable habitat:Every species has specific requirements regarding the provision of refuge, feeding and social activities by the specific habitat. Variations in the stratified woody canopy and grass height, provides different suitable habitats in the same Veld Type for a specific game species, e.g. Succulent Valley Bushveld provides nine different habitats in relation to the geological substrate. However, only three of these habitats are optimally suitable for kudu.
Kudu, being a browser primarily, prefer less dense bush enabling good visibility at head height. With frequent human disturbances, refuge is taken in dense thicket and forest-like habitats, while it is compulsory that there will be more open woodland to cater for their feeding requirements.
Impala, a mixed feeder, tolerates denser bush than kudu, but selects short grass for feeding.
Sable prefer low density savanna woodland with medium to tall grass of the less sweet species which grows on the sandy, granitic soils.
Roan prefer sweeter grass, of the same height as that preferred by sable, but in the dense woodland found on alluvial soils and basaltic plains.
Mountain Reedbuck prefer rocky outcrops and undulating terrain.
Buffalo prefer plains, marshlands and drainage lines, with abundant tall, sweet grass and open surface water.
Although some species may survive in various habitats, their production potential will seldom be realised there. Some may breed poorly, as do gemsbok in the eastern Cape, or some may take to new habitats, as do the exotic fallow deer. The most important aspect to remember is the specialized type of feeding behaviour of the different species, which differs entirely from that of domesticated livestock. There does not exist a non-selective feeding game animal. Even the bulk feeding buffalo select grass species (refer to Table 2).
An adequate forage resource:Adequacy, being a function of a certain vegetation species composition, structure, quality and quantity, as required by the different animal species and sustainability, which is a function of the forage production rate and supply within the habitat, should be adequate for the game population during the driest season. Can the vegetation supply sufficient fodder to provide in the various diet requirements of the different game species and numbers roaming the landunit? An inadequate supply limits reproduction, whereas inadequate quality, i.e. forage of low nutritive value, results in physically stressed animals and possibly in mortalities during sudden climatic changes.
Social structure: The single most important difference between livestock and game production, can be found in their social structure. Hierarchical ranking, determined by natural laws, is important in the social structure of game. Social structure is a function of home range,territoriality, social maturityand physical body conditionand differs significantly between the different game species. With solitary species, both the males and females have defined territories and home ranges with a little less than 20% overlap. Either, pair bonding as with steenbok occur, sharing one territory, or the male wanders across the bordering territories of two or more females, as is the case for duiker, bushbuck and black rhino, but here, during mating only.
For semi-gregarious species, including zebra, kudu, hartebeest, sable and impala, the males only become territorial during the rutting season. With too high a bachelor male ratio, the dominant males will spend more time fighting than in mating. Gregarious animals, giraffe, buffalo, wildebeest and springbuck, are less territorial and hence the males are less aggressive. Mating ratios may vary between 1:6 and 1:15, depending on the species. Some species form strict lifelong family bonds, i.e. buffalo, zebra and sable. With kudu, giraffe, springbuck and impala, the groups constantly restructure on account of the movement of individuals between groups, only forming temporary associations. Individuals of the latter species will however, remain on a defined home range that may overlap with another by as much as 80% (Furstenburg Undated). These ranges are not specifically occupied by groups, but rather by individual animals.
Overlapping in the case of the strict family and pair bonding species, rarely exceeds 20% (Furstenburg Undated). Higher animal densities can be maintained for species where a larger overlap of home ranges occur, provided the carrying capacity is not exceeded. Socially immature males consume forage and take up space that could otherwise be used by productive females. Hence, if trophy production is the aim, a herd of unproductive bulls have to be maintained in the interim in order to prevent the bull structure declining due to advancing age.
Farm size: This is the single most important parameter with the biggest influence on budgets and turnover and which determines the viability of the ranch or game production system. It limits animal numbers and the species composition that can be run on the farm. Game may not be stocked according to the size of the ranch or farm. The percentage suitability of each variation in the habitat on the farm has to be defined very carefully for every game species considered for the farm. Numbers of animals must be calculated for each species individually, given the proportional size of the suitable habitat, multiplied by its percentage suitability.
Carrying capacity:The carrying capacity follows the general agricultural grazing capacity norm according to the ecological status of the veld. This is the most unstable feature of the habitat, changing with climatic fluctuations and varying veld condition. A maximum density, i.e., level of saturation, exists for every animal species on every land unit, in proportion to the size of suitable habitat. Beyond the saturation level, social behavioural needs inhibit any further increase in density. By definition, carrying capacity is the number of Large Stock Units that can be carried per hectare per year(LSU.ha-1.yr-1), without deterioration occurring in the habitat.
One LSU is defined as a 450-kg steer, feeding exclusively on grass and gaining 500 grammes per day. Important parameters which affect the carrying capacities of game are: a) Minimum hectare per Animal Unit (ha/animal) of optimal habitat needed to fulfill the varied requirements of dietary fodder needed year round; b) Minimum Habitat Area (ha) per animal or associated animal groups (family) needed to fulfill the social and spatial needs of the species; and c) Browser Equivalent Unit for browser animals, where one browser unit equals a 140 kg kudu feeding on 1500 edible, acceptable trees/shrubs with a canopy height of between 0,6 to 2,0 m and which retain over 35% of its foliage year round (Furstenburg Undated)(refer to Table 3).
Every landunit or farm differs from another and each one has its own unique carrying capacity and game composition potential. General norms for stocking game do not exist for the major Veld Types. Landowners who try to optimize game production by applying the so-called “general norms”, grope in the dark. The smaller the scale of farming operation, the larger is the error. No two farms can be compared or managed alike for game production. Professional advice and planning are needed continuously, since environments, climate and management objectives are not stable, but forever changing. For every individual landunit, production optimization is a rule of thumb which cannot be generalized.
Reproduction physiology:This concept refers to the sexual and social maturity ages and the natural and optimal male : female mating ratios.Production potential, i.e. reproduction, is a function of the sexual and age structure of the population and of the physical condition of individuals. Physical condition is a function of social and spatial structure, i.e. degree of stress, and abundance and quality of the food supply. Degree of social and spatial stress is determined by animal density, which include animal numbers and land-unit size and the species interaction, determined by the animal-species composition. Food supply is determined by habitat, climate and veld-condition.
For example:
Springbuck become socially mature at nine months of age, females and 20 months of age, males. Gestation period is 5½ months. An ewe can give birth for the first time at 15 months of age and under optimal conditions, every seven months after that. They may produce 16 to 18 lambs throughout their expected life-span of 10 years.
Kudu reaches sexual maturity at 16 months of age, females and 24 months of age, males; they become socially mature at 20 months of age, females and at three years of age, males. Gestation period is eight months. A cow may produce only 4 to 7 calves over her expected life-span of 6 to 9 years (Furstenburg Undated); the life span of males is 12 years.
Buffalo cows reaches social maturity at four years of age with a gestation period of 11 months, but with a calving interval of 20 to 26 months and a life-span of 20 years, producing a maximum of seven calves per cow.
Solitary game species mate at a ratio of 1 male : 1 to 2 females; semi-gregarious species at 1:4 to 6; and gregarious species at 1:10 to 15. Natural ratios in populations are generally 1:1 to 2 on account of the natural birth ratio of 50% male and 50% female. Therefore, up to 75% of the males in the population is either socially immature or too old or socially post-mature to compete with the stronger younger mature males and therefore do not breed. An important feature with game is that only the dominant males and socially mature females breed. For some species like the impala, females are very particular in their choice of a male. Inferior rams are ignored by the ewes. With larger gregarious animals the hierarchy is less strict and some sub-adult males will mate, but only with sub-adult females.
7.Maturity:
Sexual maturity: The age at which the animal has reached sexual maturity physiologically and the animals are fertile, then they are able to mate with a female.
Social maturity: The age at which the animal has developed sufficient body strength to repel opposition by its own sex when making overtures to the opposite sex. The animal can now ensure that his own genes will be transferred to future generations during reproduction. The animal is now able to play a leading role within the social hierarchy of the population.
Post-maturity: The animal has lost its strength to compete for social dominance, or it has become infertile, but is still dominant and this keeps fertile males from mating.
Sub-adult: The period from the stage when sexual maturity is reached up to the average age at which members of the species generally reach social maturity.
Calf / lamb: Generally from birth up to the age of one year.
Youngster: From one year of age until sexual maturity is reached.
Sub-adult males render the least contribution to animal production on the game farm. They consume forage and utilize the habitat and fill up the animal load in terms of roaming space and carrying capacity, while they do not contribute to reproduction. In most cases they also have no value as trophies. Management must keep the number of sub-adult males low. Only sufficient replacement males must be kept on the farm, in accordance with the number of breeding herds in the population.
Ageing criteria:This is probably the most ignored parameter in the management of a game population for production, it is the rate of body growth and the social hierarchical rank of the animal relative to its age. Maximum production versus the maximum production of trophy animals is in direct conflict. When managing for maximum production with kudu, the sexual ratio of socially mature animals have to be kept to between 1 male : 3 to 5 females, never to exceed a ratio of 1:8. It is important to note that trophy status in the kudu is only reached at over 8 years of age (Furstenburg Undated)(Fig. 1).
Once the population has reached ecological equilibrium, optimal sustainable take-off, i.e. reproduction in kudu is only 19%, with a range of between 12 to 26%, this figure depends largely on rainfall. Kudu cows increase in body weight up to the age of 4 years, after which growth stabilises, only to start deteriorating from 5.5 years of age. Sudden cold and wet spells experienced after 5 years of age and during droughts, cause up to 75% of all females over 5 years of age to die (Furstenburg Undated). With the above take-off figures in mind, 44% of take-off need to be old females over 5 years of age, 44% of socially mature males, of 3 years of age and only 12% trophy animals, which should be over 8 years of age.
A population of 250 kudu kept on 3000 ha of suitable habitat: a) for maximum animal production – management will yield a sustained growth rate of 34 animals; with annual take-off figures of 15 old females, 15 males of 3 years of age and only four trophy bulls; b) For maximum trophy production – management will yield a growth rate of 22 animals; with annual take-off figures of 11 old cows and 11 trophy bulls, 6 of 8 years of age and 5 of 10 years of age. Old cows have to be culled as they start deteriorating after five years of age with an ever increasing risk of mortality during sudden climatic fluctuations (Fig. 2). Population growth reaches a plateau at a sexual ratio of 1:4 to 5. After this, females have to be taken off regularly in order to sustain optimal reproduction. Allowing more males in the age group of 4 to 7 years, intended for maximum trophy production, will result in over stocking of the farm. Consequently, more females will have to be taken off to maintain the stocking rate, this leads to a reduction in the total population production, i.e. in reproduction.
35% of the total population springbuck at the saturated equilibrium, may be harvested annually. The harvest ratio will be 49% females, of over 4 years of age, 45% socially mature males, of 2 years of age and 6% older males, of over 3 years of age.
Population dynamics are extremely sensitive to sudden changes in management. One poorly judged harvest of the sexually active age hierarchy of a kudu population can reduce their production by more than 30%. The population may then take 4 to 12 years to recover, depending on the size of the habitat, population size and rainfall. Species which have high reproduction potentials such as springbuck, are just as sensitive, but their recovery rate is much faster, rate of recovery may be as low as 2 years. On larger land units, the reduced population growth rate, due to a poorly judged harvest will be counterbalanced by the higher animal numbers carried in the larger habitat.
Stocking rate, i.e. the animal load as a percentage of the carrying capacity:The number of animals to be kept on any land unit is determined by: the habitat-area size, provided that it is suitable for the species; the carrying capacity of the unit; the social and spatial needs of the animals; and, the animal-species composition, i.e. interaction and composition. For example: On a land unit with a size of 6000 ha, with a carrying capacity of 10 ha/LSU/yr, the stocking rate equals 600 LSU’s; 6000 ha is suitable habitat in the case of roan and cattle, but only 4000 ha of this property may contain suitable habitat for kudu and black rhino;
Rhino are highly solitary animals with a home range of 200 ha per individual or breeding pair, there is less than 20% overlap, thus the ranch has room for 25 plus 50% pairs, which calculates to 37 animals. By LSU definition, one rhino is equal to 1.67 LSU’s, the ranch could maintain 239 rhino. However, dietary and social needs require 30 ha/animal, this reduces the carrying capacity of the ranch for black rhino to 133 animals.
Kudu are gregarious animals, the average group size is 6, but they are not territorial and have a home range of 250 ha, with up to 80% overlap, therefore the ranch can carry 7680 animals. By LSU definition, one kudu is equal to 0.4 LSU’s, which means that the ranch could maintain 1000 kudu. However, dietary and social needs require 12 ha/animal, which reduces the carrying capacity of the ranch for kudu to 333 animals.
Roan are gregarious animals, the average group size is 15, they are highly territorial, with a home range of 2000 ha, with less than 20% overlap. Therefore the ranch can carry 50 animals. By LSU definition, one roan is equal to 0.59 LSU’s, which means that the ranch could maintain 1017 roan. However, dietary and social needs require 30 ha/animal, which reduces the carrying capacity of the ranch to 200 animals.
Cattle: By LSU definition the ranch could maintain 600 head of cattle.
By reason of the parameter limiting the individual species needs the most, with reference to single species, the ranch can maintain a maximum of: 37 rhino, by reason of their home range; or 333 kudu, by reason of their ha/animal need; or 50 roan, by reason of their home range; or 600 cattle, by reason of the LSU definition. When carrying all four species, the number per species still have to be adjusted to fit into the total of 600 LSU’s, of the grazing as well as the browsing capacity of the ranch. If mixed feeder species are to be included into this game composition, browsing and grazing capacity will have to be allocated proportionally to the percentage of either, consumed by the mixed feeder species.
Animal species composition:The species composition is determined by: a) the objectives set by the land owner, b) the suitability of the different types of habitat available, c) the species interaction and d) the market. Greater species diversity is required for eco-tourism, which obviously means fewer animals per species, this puts the populations at the bottom of the exponential growth curve (Fig. 3) and production is therefore decreased. Income will now have to be generated from eco-tourism, as harvesting of the population will be unsustainable. If it is the intention to keep game for game production, local hunting, live and venison sales, larger numbers of fewer species are to be considered, which will put the population higher on the exponential growth curve and lead to a higher production.
Management objectives of the land owner:For which market does the land owner manage and produce his animals? What is the scale of the farming operation and the time frame dictating production. The main parameters are the financial outlay of the landowner and his aesthetic values with regard to wildlife. When starting a new venture, introducing game at numbers lower than 20 individuals per species will only generate a return on the investment after 5 to 7 years, in the case of most of the median to larger game species. Bridging capital will be needed to see the owner through this period.
Optimizing production
A ranch needs to be divided into vegetation’s structural, floristic and landscape units, encompassing far more than the superficial descriptions of biome or vegetation type. These units determine the different habitat requirements of each animal species.
The percentage suitability of every unit on the ranch needs to be ranked and quantified with respect to inter alia forage production and cover for each animal species. The criteria of selective, non-selective and browsing game feeding as used in the past, is completely inadequate as ranking parameters, since there is no non-selectively feeding game animal.
Quite apart from their feeding behaviour, game animals are also to be ranked according to their social and spatial needs. This has proved to have an even greater effect on game production than feeding.
Every potential game species for which the habitat may be suitable, described by some quantified measure, is then allocated to the game herd at an appropriate rate of stocking.
Stocking rate is calculated by the factor most limiting to the animals performance potential, which is expressed either by large stock unit carrying capacity, browser unit carrying capacity, minimal social roaming space, or minimal feeding space.
The proportion of browse and grass taken by each animal species are to be distinguished, quantified and treated separately with regard to the forage potential of the habitat.
Divide the most limiting parameter into the sum of the allocated percentage suitabilities of all the potential habitats. The answer to this calculation will provide the maximum number of animals per species that can be run sustainably as a single species on the landunit.
Define the different ratios of feeding structure of the different animals that are to be run on the farm; i.e. the ratios of highly selective short grass grazers to bulk grazers to browsers to intermediate low-selective grazers.
Once the maximum load for every suitable game species had been calculated, the species composition can be selected with due regard to animal performance potential, long-term vision, objectives and the market to be entered (Table 4).
Population dynamics in production modelling
Once the objectives have been set, the landowner needs to know how to manage and what to expect as a result of his management. Especially the smaller populations of most game species are extremely sensitive to changes in the sexual and age structure of the population due to harvesting, be it hunting, culling, capturing or introductions. Natural growth rate norms have been compiled for every game species individually. By studying the natural behavioural needs of each species, production can be optimized by manipulating the sexual and age structure of the population to a certain extent by applying domestic livestock principles. Natural production is now transformed into an intensively managed farming operation, which means maximum sustainable annual production and harvesting. The essence of game production has now become maximum use and filling up the entire range of feeding niches occurring on the farm, to maximum capacity. This was done a) with animals with the highest performance possible, b) with minimal interactive competition between animals and, c) without a degrading trend taking place in either the overall forage production potential and/or in the specialized structural environmental features and conditions needed for performance by some of the suitable and chosen species.
At first glance this all seems very complex and beyond reach. The whole exercise is certainly complex. However, once the principles are clearly understood and a certain amount of knowledge is gained for every animal species, by the scientist and manager, the picture starts unfolding itself. Reality becomes plain. Most of the behavioural and performance information needed, concerning the different animal species are published. It needs to be reviewed in an holistic approach. The most important approach is to define and break down the given habitats on the ranch into detailed niches and not to merely stick to vegetation types.
When the carrying capacity of the farm has been reached by the number of game stocked, either by virtue of their LSU equivalents or by the minimum roaming space needed, the number of animals in the population have to be effectively managed by the correct rate of take-off. This can be done in two ways: a) to achieve the optimal sexual ratio for maximum breeding and therefore for maximum production, male animals will have to be reduced. This will affect mainly the sub-adults. The individuals hunted for trophies only, by professional hunters, will have little impact on reducing animal numbers in the population, especially if this is a game species where the males take 4 years or more to reach trophy status, this aspect applies to the majority of the species; b) the size of the population, i.e. the number of animals are managed by taking off the old mature and post mature females. Reducing these females will have a direct impact on animal numbers as well as an immediate reduction in the exponential reproduction rate of the species.
Regarding the fluctuating conditions in climate and veld, the manager will have to follow a sensitive balance with regard to his vision and the farming objectives, in order to manage and maintain the correct number of animals per species at the maximum potential carrying capacity of the habitat. The maximum production rate need to be maintained by management to keep the maximum number of animals. In contrast to domestic livestock, production can be allowed to extend beyond the carrying capacity of the farm, but only with regard to the roaming space needed by the animals, not by LSU equivalents, with the proviso that the annual takeoff equals the annual reproduction rate as dictated by the specific year’s climatic conditions. Lambs and calves do not take up any social roaming space within the behavioural niche of the species. Bear in mind that game is being managed in terms of numbers and not in terms of metabolic mass. Initially the carrying capacity is calculated with due regard to metabolic mass. By only utilizing sub-adult and adult animals, to maintain the animal numbers within the carrying capacity, the metabolic mass of the population will never exceed the ecological carrying capacity of the land. The adults removed by takeoff, get replaced during the following season by infants only, of far less mass.
By scientifically managing sexual and age ratios or structures correctly, the production of semi-gregarious animals can be increased by 3 to 10%. Production norms vary with climatic conditions. For kudu it can vary from 12 to 26% between dry and wet years. Sub-adult males will mate with sub-adult females, only during years of good rainfall and extremely good veld conditions. Game production therefore follows a cyclically fluctuating trend intimately related to climatic conditions, displaying frequent dry and wet periods. Game numbers have to be managed accordingly. There are four broad climatic cycles: a) a short-term, unstable, wet-dry cycle ranging from 6 to 12 years each, b) a medium term, stable cycle ranging from 18 to 23 years each, c) a longer-term, highly stable cycle of 45 years, and d) a super long-term, highly stable cycle of 88 years (Furstenburg Undated).
Whenever two or more of these cycles coincide at the top asymptote, wet, severe wet conditions, i.e. flooding will occur or, at the bottom asymptote, dry, severe droughts will occur. Under these conditions, old female animals which have stopped breeding and/or for which the risk of mortalities increase, are taken off. At the same time, males are taken off mainly as sub-adult animals. Only a few replacement males and females for trophy hunting are left out of each year’s population increase.
With some species, the optimal trophy age is reached during the peak breeding age, this will usually be the dominant breeding males. After this age the quality of the trophy starts to deteriorate as it does with Wildebeest. In the case of other species such as buffalo and kudu, optimal trophy status is reached during the post-breeding ages, these are normally old, outcast males. The manager has to get to know at which age each species reaches maximum trophy status and he will then have to manage accordingly.
Conclusions with regard to game introduction
Numbers build numbers. For economical game production, large numbers, i.e. viable breeding populations of only a few game species are necessary. In most cases the valued game species have low reproduction rates. Starting off with only 20 buffalo it will take 10 years to reach a population size of 70, whereas, starting off with 20 springbuck, a population of 750 will be reached within 10 years. On smaller game farms, i.e. those less than 3000 ha in extent, lower animal numbers can be kept, for reasons explained previously and, therefore, the high production exponential phase will never be reached for a species. Therefore, it is of the utmost importance to keep fewer species, no more than five, in order to keep the numbers per species as high as possible so that the production rate will reach the exponential phase.
References
Falkena H & Van Hoven W 2000. Bulls, bears and lions: Game ranch profitability in southern Africa. SA Financial Sector Forum Publications, Rivonia, SA. pp69.
Furstenburg D 1998. Game Production: Limitations set by land area, breeding and population dynamics. Pelea 17:25-37.
Furstenburg D Undated. The influence of environmental and animal factors sustaining production in semi-arid vegetation. Ph.D. thesis, to be submitted to the University of Port Elizabeth. pp567.
Furstenburg D, Kleynhans M & Barnard HJ In press. Integrated kudu, duiker, bushbuck and Boer goat production systems in Valley Bushveld: Ecological interactions, processes and constraints. Pelea 21st Anniversary Scientific Edition, pp11.
Hugo A 2000. Value adding to venison. Unpublished report, University of the Free State, pp5.
Laubsher K 2000. Game farming as a business – a strategic view. Unpublished report, University of the Free State, pp7.
Peace Parks Foundation 2001. Mapping the way ahead. Africa Environment & Wildlife 8(11):94-95.
Table 1: The most important ecological differences between game and domestic livestock production systems
GAME LIVESTOCK
Social hierarchy and spatial separationTerritorial behaviour importantMigration with larger and more gregarious species
Co-existence of various species
Multi species conundrum
Self regulating, harmonic ecological equilibrium of co-existence between plants and animals
Ecosystem adapted for co-existence of species
Niche separation
Stratified feeding to minimize species competition
Production for quality and strength
Co-evolution is positive, it inforces the ecosystem
Eco-production principle
Forward succession of the resource
Carrying capacity based upon animal social needs and habitat requirements
Natural social structure are lostNo territorial behaviour
No migration
Loss of co-existence
Mono species culture
Opportunistic machines only to be controlled by the manager himself
Exotic animals being bred to take maximum advantage of the system, to the detriment of other species
Loss of niche separation
Maximum competition
Production for quantity
Co-evolution is negative, it demolishes the ecosystem
Exploitation principle
Backward succession of the resource
Carrying capacity based upon fodder production, consumption and Veld Type
Table 2: A detailed breakdown of the feeding behaviour of game
Species/Feeding type Selectiveness Grass Tallness Grass Nutritiveness
BROWSERS
Kudu (Forbs)GiraffeCommon duiker (Forbs)
Black rhino (Forbs)
Bushbuch (Forbs)
Nyala (Forbs)
Klipspringer
HighHigh – ConcentrateHigh – Concentrate
High
High – Concentrate
High – Concentrate High – Concentrate
6 – 30 cm6 – 30 cm1 – 8 cm
6 – 30 cm
6 – 30 cm
6 – 30 cm
6 – 30 cm
MixedMixedMixed
Mixed
Sweet
Sweet
Sweet
MIXED FEEDERS (Browse; Grass; Forbs)
ElandGemsbokImpala
Springbuck
Grysbok
Steenbok
Elephant
Fallow Deer
Boergoat
Grey Rhebuck
PartPartHigh – Concentrate
High
High – Concentrate
High – Concentrate
Low – Bulk
Part
Part
High
6 – 30 cm6 – 30 cm1 – 8 cm
1 – 8 cm
1 – 8 cm
1 – 8 cm
6 – 150 cm
6 – 30 cm
1 – 30 cm
6 – 30 cm
Mixed/SourSweet/MixedSweet
Sweet
Sweet
Sweet/Mixed
Sweet/ Mixed
Sweet/Mixed
Sweet/Mixed
Mixed/Sour
GRAZERS
BuffaloWaterbuckRoan
Sable
Zebra (Hartmann Mountain)
Zebra (Cape Mountain)
Zebra (Burchell)
White rhino
Tsessebe
Blesbok
Oribi
Bushpig
Warthog
Red hartebeest
Ostrich
Black wildebeest
Blue wildebeest
Bontebok
Lechwe
Common reedbuck
Mountain reedbuck
Low – bulkPartPart
Part
Part
Part
Part
Low – bulk
Part
High
High
High – concentrate
High
Part
High
High
High
High
Part
Part
Part
6 – 150 cm6 – 30 cm6 – 150 cm
25 – 150cm
6 – 30 cm
6 – 30 cm
6 – 30 cm
6 – 30 cm
6 – 30 cm
1 – 8 cm
6 – 30 cm
1 – 8 cm
1 – 8 cm
6 – 30 cm
1 – 8 cm
1 – 8 cm
1 – 8 cm
1 – 8 cm
6 – 150 cm
25 – 150cm
1 – 30 cm
Sweet/mixedSweet/mixedSweet/mixed
Sweet/mixed
Mixed/sour
Mixed/sour
Sweet/mixed
Sweet/mixed
Sweet/mixed
Mixed/sour
Mixed
Sweet
Sweet
Mixed
Sweet
Mixed/sour
Sweet/mixed
Sweet/mixed
Sweet/mixed
Sweet/mixed
Mixed/sour
Table 3: The minimum game stocking criteria for optimally suitable habitat conditions
Species LSU equivalents Browser equivalents Minimum ha/animal(feeding needs) Min. size habitat-area(social needs)
Browsers
Kudu (forbs)GiraffeCommon duiker (forbs)
Black rhino (forbs)
Bushbuck (forbs)
Nyala (forbs)
0.401.600.07
1.67
0.13
0.26
1.004.100.02
4.17
0.33
0.65
12803
30
4
8
250 ha900 ha3 ha
200 ha
4 ha
80 ha
Mixed Feeders (Browse; Grass; Forbs)
ElandGemsbokImpala
Springbuck
Grysbok
Steenbok
Elephant
Fallow deer
Boergoat
Grey rhebuck
0.900.430.16
0.11
0.06
0.06
2.50
0.26
0.17
0.09
2.250.800.40
0.28
0.15
0.15
6.25
0.65
0.45
0.30
22206
10
4
4
500
9
2
12
200 ha450 ha150 ha
100 ha
10 ha
30 ha
2000 ha
200 ha
20 ha
120 ha
Grazers
BuffaloWaterbuckZebra (Hartmann)
Zebra (Burchell)
White rhino
Tsessebe
Blesbok
Bushpig
Warthog
Red hartebeest
Ostrich
Black widebeest
Blue wildebeest
Bontebok
Lechwe
Common reedbuck
Mountain reedbuck
1.000.450.50
0.70
2.50
0.34
0.21
0.20
0.13
0.50
0.24
0.35
0.50
0.21
0.28
0.20
0.10
0.000.000.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
301525
25
30
20
15
8
15
20
20
20
20
15
15
5
5
1200 ha300 ha500 ha
800 ha
600 ha
400 ha
200 ha
150 ha
60 ha
300 ha
60 ha
400 ha
300 ha
150 ha
120 ha
70 ha
60 ha
Table 4: General production norms for the different game species under optimal habitat conditions; This is the annual increase in the population size, taking natural mortalities into account
Species
KuduWildebeestEland
Bushbuck
Warthog
Waterbuck
Blesbok
Steenbok
Gemsbuck
Red Lechwe
19%30%20%
20%
120%
20%
28%
30%
15%
25%
Common DuikerRed HartebeestMountain Reedbuck
Hippopotamus
Grey Rhebuck
Springbuck
Bontebok
Klipspringer
Fallow Deer
Common Reedbuck
45%23%29%
20%
20%
33%
25%
30%
35-60%
18%
OstrichImpalaZebra
Giraffe
Buffalo
Elephant
Sable
Rhino
Nyala
Average norm
40%30%25%
12%
14%
20%
20%
12%
28%
25%
optimising game production 1Fig. 1 Trophy growth for kudu bulls, length in mm, based on annual increments measured in 242 animals (Furstenburg Undated)
optimising game production 2Fig. 2 Body growth rate in kudu in relation to age, determined from 440 animals harvested at the Kirkwood Prison Farm between 1989 to 1993 (Furstenburg Undated)
optimising game production 3
Fig. 3 The expected optimal population growth rate for kudu under optimal, sustainable habitat conditions. Annual rainfall 300-400 mm, maintained at the median, starting off with only 20 animals. Habitat size is unlimited. Exponential growth only commences once a number of 200 animals are exceeded. Minimum numbers are taken off in order to maintain the optimal sex ratio
Published
Karoo Agric 5 (1)
