WINDHOEK – Namibian Farmers have responded in big numbers to last week’s article in Farmers’ Forum on cactus (prickly) pear cladode production as a good enterprise for farmers in semi-arid and arid parts of South Africa and especially Namibia.
It has, once again, raised the issue of how to produce extra fodder and the prickly pear is highly sought- after as animal feed. One of the country’s foremost experts on the topic is independent consultant, Dr Axel Rothauge, who says in the drier southern, western and north-western parts of Namibia, the best option for extra fodder is to establish plantations of drought-tolerant fodder shrubs such as the well-known exotic oldman saltbush (Atriplex nummularia), Australian bluebush (Kochia brevifolia), spineless cactus (Opuntia ficus-indica, and Mexican aloe (Agave mexicana).
He says the spineless cactus also produces a delicious fruit, which can be sold for a cash income that more than pays for the establishment of the plantation. “If you think big, cactus pear can even be exported. Spineless cactus used to be a common drought fodder grown on huge plantations in southern Namibia, but its popularity has waned recently as 15 years of good rains lulled us to sleep,” he is quoted. Dr Axel Rothauge says several indigenous shrubs with fodder production potential can be tried out as well like the Salvadora persica or mustard bush, which is a slow-growing but highly palatable shrub that prefers to grow in loamy soils and on river banks. It is one of the principal fodder species of the Topnaar’s goats along the Kuiseb River and used to grow all over the many small streams and rivulets that criss-cross southern, western and north-western Namibia.
However, unrestricted browsing by goats has wiped it off many landscapes. The bush seeds profusely in summer and grows easily from seed. The seeds contain a valuable detergent oil that can be harvested commercially when the plant is not being browsed. Salvadora seed oil is a valuable alternative to coconut oil in the soap and detergent industry. Cattle find the mustard bush’s leaves highly palatable. Where-ever it is easily accessible on flat ground, the plant has been killed by over-browsing and only its thick, gnarled woody stem remains to show what once was. Various Salsola species (gannabosse) grow in arid Namibia, are highly drought-tolerant, palatable and stay green even during the driest of seasons. They often grow on poor and brak (alkaline) soils but are not very productive. They can probably be propagated vegetatively by rooted cuttings.
Phaeoptilum spinosum, the brosdoring is the principal browse plant of goats and kudu in central Namibia, is drought-tolerant, adapted to dystrophic (infertile) and shallow soils and grows easily from seed. It flowers in October when the veld is still dry. Its beautiful winged fruit in all shades of red from rose pink to deep burgundy turn it into a spectacular sight. These fodder shrubs should be established in fenced plantations. They are suitable for areas with poor or saline soil or with active soil erosion because they bind soil and prevent further erosion. Normally, well established plants do not need to be watered. To produce 1 kg of dry fodder, an agave needs 93 liters of water, spineless cactus 267, oldman saltbush 304 and maize, by comparison, needs 469 liters of water. In the drier areas of Namibia, a plantation of drought-tolerant fodder crops can produce up to two tonnes dry material per hectare, which could maintain a herd of 20 non-lactating Sanga cows for nearly three weeks. In addition, the fenced plantation can serve as a seed reserve of good grazing grasses.
“Plantations should not be browsed during the rainy season and protected from browsing livestock by wire or bush fence to be able to build up a good supply of fodder. The fence can be opened during the dry season or drought to allow livestock to utilize the accumulated fodder.
Most exotic drought-tolerant shrubs are not very nutritious and only supply a maintenance or sub-maintenance diet which only just keeps animals alive during a drought (at maintenance level). Although they can provide the bulk of an animal’s diet during a drought, they should not serve as only fodder for long because most are nutritionally imbalanced: they contain too little protein and too much sodium and calcium (minerals, see table below), which has a slight laxative effect on animals. If mixed with other feedstuffs, drought-tolerant bush fodder can form a balanced diet that can be used in fodder-based feedlots. Since Mexican aloe fed as an only feed can cause paralysis and its yield is the lowest of all drought-tolerant fodder crops, it is least suitable for Namibia’s dry areas,” he concludes.