In Namibia, livestock production is heavily dependent on rangeland, which supports a diverse range of forage resources, including trees, shrubs, grasses and forbs. 

These plants differ in growth forms, structure, life cycles, habitat preferences and uses. Cattle, sheep and goats characterise livestock farming in this country. 

These animals have different forage preferences and foraging habits. 

Cattle and sheep are predominant grazers (grass-eaters), whereas goats are browsers (eating leaves and twigs). However, these animals can still use any forage resource available to meet their daily feed intake and nutritional needs.  For example, goats do eat grass, and cattle also browse.

When describing a grazing area, several key attributes should be considered to determine its grazing value.  These are grass species’ composition, frequency, abundance, richness and density.

Fundamentally, the quality of the grass plant can be attributed to its species, growth structure and life cycle. 

Farmers commonly use the term palatability as an assertion of the quality of the grass. However, different grass species have different levels of palatability.  A palatable grass is one that an animal is attracted to or selects, among others, to graze.

This is influenced by its smell, taste, nutrients and digestibility. 

Therefore, selective grazing becomes particularly hazardous, especially when the diversity or composition of species is narrow, thereby leading to the local extinction of sensitive and valuable grass species.

One of the essential attributes that farmers should understand is the grass life cycle or its lifespan. There are two different lifespans under which grasses can be classified, annual and perennial. 

Annual grasses refer to grasses that have a shorter lifespan of less than a year.  They grow fast, produce seeds quickly and shed seeds for reseeding, and then the mother plant dies.

Typically, annual grasses emerge with the first rainfall or are visible only during the wet season. 

However, they disappear by August, coinciding with the onset of the dry season. These types of grasses dominate many grazing areas in Namibia, with their dominance increasing as rangeland degradation progresses.

On the other hand, perennial grasses have a longer lifespan and persist for several years.  Unlike annuals, they do not die after shedding seeds but only undergo a dormancy period (stop growing) during the dry season to conserve nutrients for regrowth from the same stump in the next rainy season. There are many different species of perennial grasses. 

However, not all are palatable or well-utilised by grazing animals. 

The most valuable perennial grasses are more sensitive to continuous grazing.

 Thus, their dominance decreases with the overgrazing and degradation of rangelands, giving rise to the aggressive establishment of annual grasses.

To make informed grazing management decisions, farmers need to know and understand the impact of the prevailing ecological perturbations, including herbivory, climate, as well as intra- and inter-specific species competition. 

The reaction of the rangeland to these perturbations can be observed through its plant population establishment and distribution.The dominant annual grasses in almost all grazing areas in Namibia currently include Schmidtia kalahariensis, Chloris virgata, Eragrostis porosa, Eneapogon cencroides and Urochloa brachyura. 

The dominating perennial grasses are Stipagrostis uniplumis, Stipagrostis obtusa, Stipagrostis hochstetteriana, Eragrostis pallens, Eragrostis rigidior and Aristida stipitata.

The most valuable perennial grasses, such as Cenchrus ciliaris, Brachiaria nigropedata, Anthephora pubescens and Schmidtia pappophoroides, are observed only in well-managed or least disturbed areas in some parts of the country.

Farmers can gain more knowledge about these grasses from descriptive literature books (e.g., Grasses of Namibia), where they can also find common names.

These literature materials and information can be found on the internet, bookshops, the Namibia Botanical Research Institute and university libraries.

Farmers should engage in restorative practices on their rangelands. These include improving soil conditions, controlling bush densities and reintroducing valuable perennial grasses by reseeding their grazing areas and cultivating them in gardens or crop fields.

These efforts should all be aimed at reducing pressure and adding value to the rangelands, ensuring sustainable fodder availability for livestock. 

*Erastus Ngaruka is Agribank’s technical advisor on livestock and rangeland.