WINDHOEK -If grazing animals are not supplemented in winter, their production and fertility declines. They become stunted and if pregnant, are unable to carry the foetus to term or raise offspring to maturity. This is typically the case in communal areas where few farmers can afford to invest in lick supplements. If there is no investment in a factory, there is also usually little production, says Dr Axel Rothauge, foremost expert on animal supplementation.
Studies have proven the worth of animal supplementation in winter as Dr Rothauge explains:
“From May onwards, perennial grasses become dormant in preparation for winter. Sending their starches and proteins to the roots and crowns gets them out of harms’ way so that they are not lost to frost, fire or grazing and are available for next season’s re-growth. Annual grasses and herbs die off, having invested most of their nutrients in seeds that ensures generational succession when next it rains. These survival mechanisms of grasses means that grazing animals experience quite a severe deficiency of various nutrients in winter, the dormant season of vegetation. Veld in poor condition with annual grasses dominating contains even less nutrients than veld in better condition, with abundant and diverse perennial grasses,” he says.
According to him, veld forage does not always contain all the nutrients needed by domestic livestock. In general, grazing is not as nutritious as browsed forage (the leaves of trees, bush and shrubs) so that grazers suffer more nutritional deficits than browsers. But grass is usually much more productive than available browse. A lot of tree leaves grow out of reach or are protected by thorns or chemicals (e.g. tannins).
Thus, there are normally many more grazers (animals that eat predominantly, but not exclusively, grass) than browsers (animals that eat predominantly, but not exclusively, the leaves of woody plants) on savannah veld.
Commercial farmers invest in lick supplements and get re-paid by higher production and fertility of their livestock. A typical winter lick contains protein, energy and minerals. The worse the condition of the grass sward on the farm, the more energy and proteins have to be supplemented to cattle and sheep. The most common and cheapest natural sources of proteins are bone, blood and carcass meal. Namibian farmers are not allowed to use these under the FAN Meat scheme because many countries that buy our meat do not want livestock to have eaten supplements of (land) animal origin, for reasons of health and hygiene. We can feed protein sources of marine origin (fish and seal meal) or protein-rich plant seeds (sunflower, cotton) which are very expensive because they feed or clothe humans. We can also use artificial protein-like supplements like urea, which is potentially toxic, not acceptable in organic production but unlimited in supply and thus relatively cheap.
The most common sources to supplement energy to livestock are starches (from grains) and sugars (molasses from cane). All are very expensive because they are human staple foods. The world is fast running out of grains to feed its 7,5 billion people (unless GMO’s are widely accepted, which is a topic for another day) and will thus become prohibitively expensive in the near future. It will be a lot cheaper for Namibian farmers to invest in their veld instead!
The content of minerals in plants is generally not linked to plant condition as minerals derive from the soil and not from plants. If there is too little of a mineral in the soil, it will be too little in plants and animals will suffer a deficiency of that mineral too. Coarse, sandy Kalahari soils are usually severely deficient in many micro-minerals such as copper, zinc, manganese and selenium. Kalahari sands cover the eastern and north-eastern parts of Namibia all the way up from Aroab in the south to Aminuis, the Omaheke, eastern Otjozondjupa and all of the northern communal areas except Kunene region. In all these areas, cattle and goats suffer sub-clinical and clinical micro-mineral deficiencies that can best be addressed by supplementing a cocktail (mixture) of micro-minerals in lick.
Micro-minerals are poorly absorbed from the gut of livestock if the diet contains high levels of calcium or is alkaline. This happens where white limestone (“kalkklip”) surfaces, as near Mariental, Kalkrand, Rehoboth, Kalkveld, Witvlei, Outjo, Otavi, Tsumeb, Etosha, Grootfontein, Kamanjab, Omakange and Outapi. Here, a micro-mineral deficiency is induced by the alkaline rumen environment and not because there is an absolute deficiency in the soil. An induced deficiency cannot be addressed by adding more micro-minerals to lick. Instead, a micro-mineral cocktail should be injected under the skin, now and in October. Since limestone soils are common all over Namibia, it is probably best to always inject micro-minerals rather than add them to lick.
Phosphorus (P) is an exceptional mineral as it is linked not only to soil but also to growth and maturity of plants. It is abundant in green plants and scarce in dry grass. P deficiency is widespread in Namibia in winter, except on the most fertile, loamy soils (as in east-central Otjozondjupa and large parts of Kunene and Karas regions). Again, P is made unavailable by an alkaline rumen environment but is needed so much (it’s a “macro”-mineral) that it cannot be injected, it has to be fed by mouth.
“When the grass turns yellow it is time to switch from summer to winter lick, from mineral to production lick. Winter licks are much more expensive and needed in greater amounts than summer licks. Apart from most macro- and all micro-minerals, the nutrients in winter lick could have been supplied by veld in good condition. The farmer who neglects his veld will pay dearly with an increased lick bill. The cheapest lick supplement is good veld, as in the “old days” when our forefathers could produce cream off the veld with only a salt lick! Those days are gone, but can return if we improve veld condition. However, this will take much effort over many decades and I wonder if we have the commitment to do it,” he concludes.
Source: STRATEGIES FOR DRY SEASON FEEDING OF ANIMALS IN NAMIBIA by J.F. Els1, P. T Jessen and H. Von Seydlitz