International attitudes to biodiversity since 2002 have presented a dilemma to the Game Industry as well as to the State and Provincial Governments in South Africa. There are many arguments, all with their own merits, for both the game conservation sector as well as for the game business sector. Some species were found permanently in some parts or regions of the province, others migrated through sporadically, and others occurred peripherally on the borders of this region.

It is important to note that habitats and flora have changed significantly since the 1700’s. Therefore the suitability of certain areas for different species has also changed markedly.  Areas which once were unsuitable for certain species, are now suitable, and vice versa. Whether a certain species will flourish on a certain farm, or not, cannot be determined merely by the fact that it occurred in that area in the 1700’s. Therefore it is necessary that you do research and determine what the specific ecological and sociological needs of a specific animal are before you decide whether or not to include it in a game management system.

Breeding And Population Growth

There is a natural order of social dominance hierarchy between the members of a population of animals, as well as direct competition between members of the same gender (particularly noticeable between males). Because of this competition, few (less than 20%) animals will begin to reproduce when they reach sexual maturity. Socially dominant individuals will prevent sub adult sexually mature individuals from mating. With intensive production, where small breeding groups are kept separately in enclosures, male competition is eliminated and sub adult sexually mature individuals will likely breed successfully. Where animals are kept in extensive natural conditions, most animals will need to achieve social adulthood before they will breed. In other words, when the animal has achieved the physical strength and size which will enable it to compete successfully in the hierarchy, it may begin to breed.

Annual population growth is not merely a measure of the rate of reproduction of female animals.  An actively managed population of 100 kudu consists of 20 adult bulls, 40 adult cows, 20 first year heifers and 20 second year heifers. The 40 cows produce 38 calves, in other words, an increase of 95%. Of these calves, 12 die before they are weaned, and 4 adults die of natural causes. The population now consists of 96 adult kudus plus 26 calves, giving 124 animals in total as opposed to 100 before breeding. The population growth is therefore 24%. 

Most calves and lambs are born in a male/female ratio of close to 1:1. In nature, there is a tendency for young adult males to move out of the population and the ratio of female adult animals therefore increases slightly. The structure of a population of adult, breeding-ready (socially mature) animals can be slightly adjusted by management, in extensive conditions, to increase population growth and so optimize production. Under intensive production, with breeding animals separated into breeding enclosures, the application of agricultural animal production principles and techniques can further enhance the gender ratio in favour of female animals (specialized expertise and advice must be sought for this).

Establishing new populations

The gender ratio of adult animals in a population becomes very important when a new species is introduced or established. This ratio needs to take into account the desired male/female ratio, and must also account for individual social competition. With several strictly territorial species eg white rhinoceros, blesbok, water buck, sable antelope, gems buck, reedbuck, and tsessebe, there needs to be a minimum of three adult males in new populations or herd. If there were only 2 males, the more dominant stronger male would continuously chase the weaker animal until it would die of starvation or exhaustion, or suffer a severe injury. If there were only one adult male in the population it would be supremely dominant and kill all male offspring, or injure them as soon as youths would attain sexual maturity.

Game population growth is generally slow (about 25%), and therefore the establishment of too small new groups of a species will mostly be uneconomical. Before one decides on the number of animals required to establish a species, one needs to study the age of social maturity/first mating, as well as the expected population growth, and to take it into account when doing the required financial planning.

Animal Capacity

Animal load and carrying capacity remain the most important, and at the same time, the most ill-understood and difficult to interpret factor involved in game management. Other than in agricultural adult animal or large stock unit (LSU), the game capacity cannot be estimated by animal LSU carrying capacity alone.  There are five components involved in calculating animal capacity in game farming:

1. Habitat and suitability:    

The hectare size of the area suitable for the species in question needs to be determined. This is usually only a fraction of the total size of the available area or farm.  The overall suitability of this allocated habitat needs to be estimated on a percentage basis (1-100%). The hectare size needs to be multiplied by this percentage (of suitability for the species in question) to determine the total amount of hectares available for the species.

2. Social behaviour space:         

Is there enough space (in hectares) to supply the needs of the particular species for territorial and home-range needs in the confines of the farm, habitat or enclosure? If not, the species may survive, but will not achieve its potential population growth. This is usually more of a limiting factor for the game stocking capacity of an area than the food supply capacity.  What is the social herd/family size of the species and how much overlap of territorial area is tolerated between neighbouring herds/families? This will give an indication of how many animals can be kept in a specific area, if enough food were available.

3. Large Stock Unit – Browsing Unit:   

Every animal species has its own large stock unit (LSU) equivalent and browsing unit (BU) equivalent. One LSU = one head of cattle with mass of 450 kg with a metabolic energy intake of 500 kJ per day. One BU = one non-lactating Kudu of 160kg.

4. Dietary intake: 

Every animal species eats a proportion of grass and non-woody plant material and a percentage of woody plant material. The LSU and BU of a particular species of game needs to be multiplied by the % intake of the respective plant materials in the diet, mentioned above. These calculated answers must be multiplied for the planned total animals of each species, and the totals of all the species on the farm or enclosure need to be added together.

5.  Carrying capacity:    

The LSU and BU carrying capacity of the vegetation of each habitat unit on the farm needs to be calculated separately. The LSU and BU of the total animal load should not exceed the calculated total LSU and BU carrying capacity of all the habitats added together. Please note that the food supply carrying capacity has a direct relationship to the rainfall of the current season as well as the long term rainfall. That is why the carrying capacity and game load will vary over time. Table 8 provides recommended game loads for specific rain fall limits within which an animal species may prosper over time. Outside of these limits, game loads will be quite different.

In most instances it will be noted that a much smaller game biomass than cattle biomass may be kept successfully on the same farm. This is due to the societal special needs as well as the diverse feed needs of game species, which are usually more limiting than the feed carrying capacity of an area. Many farmers have the perception of “My farm can carry so many LSU cattle and therefore should be able to carry the same amount of LSU for game.”  This perception is false and is not at all applicable to management of game!

Suitability of Habitat

A particular habitat, landscape or area cannot be assumed to be suitable to a game species merely because it naturally occurred there in the past. One has to consider the current condition of the habitat and determine to what extent it fulfills the requirements of the particular species. I mentioned earlier that vegetation and climate are dynamic, and over time many temporary or permanent changes occur. Few habitats are the same today as they were a few hundred years ago. The two main factors driving these changes are man and his artificial technological development, and the natural process of global warming.

The main parameters determining suitability of habitat for a particular species include: temperature (variations and limits), rainfall, topography, composition of vegetation species, vegetation structure (grass height, tree and shrub crown height and density), veldt type (sweet, sour, or mixed), nutritional value (nutrient content) of plant material, taste (phenophase and growth stage) of plant material, superficial sources of water, total available space (in hectares), and infrastructure (human disturbance).