Grazing management in harmony with nature

Be gentle with nature. Work with what you have on your farm and not with what you would have liked to have. This is the grazing management philosophy of commercial farmers Helmut and Iris Stehn from Dordabis in Namibia.

Smalhoek has mainly deep, sandy soil with scattered small pockets of clay and rocky soil.Photo: Annelie Coleman

Helmut and Iris Stehn represent the third generation of the Stehn family to farm on Smalhoek near Dordabis in Namibia. Helmut has an honours degree in rangeland management from the University of the Free State, while Iris qualified as an agriculturalist at Namibia’s Neudam Agricultural College.

Helmut’s grandparents, Rudi and Maria Mayer, settled on the land in 1931. The business was then taken over by his uncle, Willie Mayer, before the Stehns settled there in 1992. “My grandparents lived in a wattle and daub house and farmed under very taxing conditions. But, through hard work they succeeded in buying the farm from the government in 1938,” Helmut explains

When they took over in the 1990s, Helmut and Iris initially decided to introduce a terminal crossbreeding system using Braunvieh bulls on Afrikaner cows. However, they soon changed from Afrikaner cows to Sanga cows to breed smaller-framed, more fertile animals better able to survive the dry conditions in Namibia. Today, the couple has a 475-strong commercial beef cattle herd.

Grazing

A total of 4 030ha of the 4 975ha farm consists of sandy soil, with the balance being clay and rocky soil. The red Kalahari sand limits the grass species available for grazing. Willie’s objective was to introduce more climax grass species for grazing on Smalhoek, but Helmut realised the error of this. It proved impossible to establish significant patches of climax grasses such as blue buffalo grass (Cenchrus ciliaris) and Kalahari sand quick (Schmidtia pappophoroides). Blue buffalo grass calls for a lime base, while Kalahari sand quick requires a firm base. 

Consequently, Helmut and Iris resolved to do the best with the species that occur naturally on their land rather than opt for drastic veld improvement. “It soon became clear that it would be futile to try and force change on the veld,” Iris recalls. “One has to be flexible to succeed with farming under the extensive conditions in Namibia. Sustainability and not profit is our main objective.

“One can’t change nature. Any grazing programme that follows the cycles and dynamics of nature will add to profit. Silky bushman grass (Stipagrostis uniplumis) is what we have on Smalhoek and that’s what we have to manage. Giant three-awn grass (Aristida meridionalis) is a pioneer species on Smalhoek. Trying to eradicate it or replace it with other species is futile. It has a vital function in the ecosystem – in our case, to provide much-needed green forage early in spring.”

About 90% of the available forage consists of the less palatable silky bushman grass, a perennial tufted grass that grows up to 1m tall and forms large tufts with fine, silky hairs on the awns of the seed.The horizontally spreading roots are adapted to absorb even the smallest amount of moisture from the top soil. Smalhoek also has small isolated patches of sour grass (Schmidtia kalahariensis), a reasonably palatable annual favouring disturbed sandy soil.

In Namibia, with its harsh, dry conditions, good rains can see some animals in the herd gaining as much as 1kg/ day, says Helmut. The perennial nature of the silky bushman grass therefore ensures a relatively stable forage supply, but it could also be badly affected by the first frost.

Shrubs and trees

The woody component consists of camel thorn trees (Vachellia erioloba), black thorn (Senegalia mellifera) and candle thorn (Vachellia hebeclada), while a variety of dwarf shrubs such as ganna (Salsola spp.) and bushman’s candle (Sarcocaulon patersonii) on the harder soils provide valuable additional nutrition. Their resilience is an advantage in the colder winter months. A number of not very palatable forbs such as Indigofera flawicans and Requienia sphaerosperma also play an invaluable role, providing vital green feed when the rest of the veld is still dormant.

Water

Smalhoek is divided into 64 camps, with between seven and 12 camps sharing common watering points. Nine boreholes supply all the farm’s water. The aquifer, at a depth of between 50m to 100m, is strong. The average annual rainfall is between 250mm and 300mm, with a recorded maximum and minimum of 500mm and 50mm respectively. Temperatures range from below zero to more than 42°C.

A severe drought hit Namibia shortly after the Stehns settled on Smalhoek.

“During this drought, the Braunvieh proved itself, especially as a dam line. We found that medium-framed Braunvieh and Braunvieh cross heifers performed excellently, even under extreme conditions. This led to a crisscross breeding system, using Braunvieh and Sanga,” he says.

Feeding cattle during times of drought is not economical in Namibia, says Iris. Fodder is imported mainly from Zambia or South Africa and high demand pushes up the price.

The Stehns’ herd is divided into three groups: Braunvieh-type cattle, Braunvieh crossed with Sanga, and a purebred but not registered Braunvieh group. Currently, each cow herd is about 40- strong, with grower herds of up to 130 animals.

Animal recording plays a vital role on Smalhoek. The animals are weighed every three months and average daily gain and intercalving periods are calculated. Analysis has shown that fertility in the Braunvieh group is slightly lower than in the crossbred herd, but it shows the best growth.

“It became evident to us that the hybrid vigour in the crossbred herd was on the decline. So we upgraded the crossbred cattle to a purebred line again, with possible terminal crossbreeding in the future,” Iris explains. “While making these changes, we replaced the Sanga with Tuli cattle, a decision also based on coat colour. Like the Sanga, the Tuli is fertile and well-adapted to the extensive conditions here. We may have to market some of our cattle at auction and buyers prefer uniformly coloured animals.”

The bulls run permanently with the females in breeding herds of one bull and 30 cows. The females are tested for pregnancy at every three-monthly weighing session. Combined with accurate recordkeeping, this enables the Stehns to manage herd fertility in a process that’s normally associated with a time-limited breeding season. They market steers and cull heifers at between 30 months and 36 months. Calves are weaned at between five months and eight months, with heifers averaging 209kg and bull calves 219kg. Between 20% and 30% of the annual heifer crop is retained for breeding.”

Namibian meat processing company, Meatco, markets most of the animals. 

Optimal grazing

For Helmut and Iris, their greatest challenge and responsibility is to successfully convert the available grazing on Smalhoek into beef. “Silky bushman grass grows very rapidly during the rainy season, but with a higher lignin level,” explains Helmut.

“This makes the grass unpalatable and difficult for the animals to digest. Our job is to manage the system to make optimal grazing available to the animals, yet with minimum external input. In Namibia, we must also include the effect of free- range game in the grazing management equation.

On Smalhoek, the veld is grazed rotationally around watering points. The animals are not moved according to the calendar or a determined cycle, but “according to what the animals and the veld tell us,” Iris says. “We have to be flexible and keep a keen eye on key indicators such as lick intake. Increased intake indicates a decline in the nutritional value of the forage. We inspect the herds and camps every day to keep abreast of the veld condition and what is being grazed at the time. What worked last year isn’t necessarily applicable this year.”

According to Iris, this flexibility and their commitment to make the best with what they have has resulted in ample grazing on Smalhoek, despite a harsh winter and the current drought.

“During the active growing period, we keep an eye on what and where animals graze. If the grazing pattern changes, it’s an indication that the preferred grazing is no longer readily available and the cattle are seeking less acceptable alternatives. In fact, at this point they should have been moved to the next camp already.”

The Stehns feel that by doing this, they stick to the principle that a grass plant should not be defoliated by more than 50% during active growth. When grazing all camps, this also enables them to give the perennial grasses a full growing season of rest in a year with good rain.”

The rainy season usually has two rainfall periods, the ‘small rain’ from October to December and the ‘big rain’ starting in January/February. The veld’s growth period may last from January to March or April, but occasionally begins only in April. The general rule in Namibia is that at the end of the rainy season no more than 50% of the total available forage (excluding Aristida species) should be available for grazing the following year.

However, the Stehns calculate their available grazing to be 30% on the deep sandy soils, which significantly reduces the use of Stipagrostis uniplumis. On the harder and hilly parts, the utilisation of the available forage is calculated to be 50%. “We collect and weigh representative forage samples from different spots on the farm to determine the available forage and its allowable utilisation,” Helmut explains.

“We normally calculate the grazing capacity of the veld at around 34kg/ ha to 35kg/ ha live weight, but this may increase to well over 40kg/ ha live weight. The official recommendation for the area is 30kg/ha live weight.

“A major portion of the 50% of the total forage not available for animal consumption must be used by termites to get organic matter from moribund vegetation into the soil to improve it. The dry climate doesn’t normally enable fungi and bacteria micro-organisms to form compost, so nature has to find other ways to cycle nutrients,” he says.

Planning for game grazing

The Stehns’ grazing plans also provide for nearly 80 gemsbok, 100 warthog and 120 red hartebeest that roam freely, even upsetting the grazing planning from time to time. Bush encroachment is not a serious problem in Smalhoek and is mostly limited to isolated patches. The Stehns view veld and grazing management as an operational matter and just as important as livestock management. The challenge is to keep abreast of the latest research while being able to determine what will work on Smalhoek – and what will not.