*3.1.5 Conventional supplements, food industry, and agro-industrial by-products*

There are different food industry by-products and agricultural wastes that are alternative dry season livestock feed supplements. These can be of animal and plant origin or of the fermentation industry. Animal by-products include blood, bones, meat and bone offals, fat, intestine and rumen contents, whey, tannery by-products, and poultry manure [1]. By-products of plant origin consist those of the milling industry (e.g. bran, waste flour), oil industry (e.g. soya bean and sunflower cakes), sugar industry (molasses), and citrus and horticulture waste. The fermentation industry produces grain, molasses, and brewer's waste, among a large array of other by-products. By-products of plant origin are the commonly used. For instance, in the SEL, molasses is readily available as the main sugarcane processing factories in Zimbabwe are located in that area. However, high cost of transportation

#### **Figure 3.**

*Browse trees provide feed during the dry season when both the grazing resource and cereal stovers become limiting.*

**109**

*Livestock Feeds and Feeding in Semi-Arid Areas of Southern Africa*

**3.2 Recommended innovations in livestock feeds and feeding**

makes the product often quite expensive. Additionally, those of plant origin are also mostly based on staple food crops such as maize and soya bean, creating competi-

Straw ammoniation is the process of addition of urea, liquid ammonia, or ammonium bicarbonate to poor-quality cereal crop stovers in order to improve their palatability, nutritive value, and digestibility. Of these three, urea is the most readily available and easiest to handle ammonia source. Nevertheless, in the SEL, as in most rural areas, urea treatment still is not a commonly used method improvement of the feeding value of cereal stovers due to lack of expertise in carrying out the procedure, as well as unaffordability for most rural resource-poor farmers. Additionally, if not done properly, urea-treated straw can be toxic to animals and cause air pollution.

Silage is forage produced from the fermentation process of chopped fresh green

Other potential technologies include intercropping cereals with ley (dual-purpose)

legumes [38]. Ley legumes provide protein-rich fodder, improve the productivity of cereal crops by increasing the amount of nitrogen available for uptake, as well as offer a possible lower-cost alternative to nitrogen fertilisers [39, 40]. In addition to cut and carry systems for feeding fresh plant material, leaf meals can also be produced by drying harvested leaf material under shed. The commonly grown multipurpose trees include *Leucaena leucocephala*, *Calliandra calothyrsus*, and *Gliricidia sepium.* The leaf meal can then be incorporated in home-made livestock rations. Cutting and drying herbage from forage and multipurpose trees can also increase feed availability. Multipurpose trees can be grown in alleys as live boundaries, home gardens, and

There are generally four fundamental principles of rangeland management which are important in order to improve condition and stability of the veld and consequently increase feed. They are rest, removal of top hamper, period of stay, and stocking density. Rest facilitates replenishment of plant growth reserves and also sets seed after defoliation. Top hamper is dead plant material accumulation which causes shading out of new shoots as they develop. It represents a nutrient bottleneck by preventing plant material from recycling back into the soil. It should therefore be removed. Another principle of rangeland management is control of period of

material under anaerobic conditions. These materials include fodder or forage grasses. Ensiling maize has been shown to improve feed digestibility and reduce methane gas production by 30% compared to feeding dry maize [37]. However, despite silages being advantageous in areas of water shortages, as well as reducing tannins due to the heat produced during the incubation period, silage production is

*DOI: http://dx.doi.org/10.5772/intechopen.90109*

tion in use between humans and livestock.

*3.2.1 Straw ammoniation*

not common among farmers.

contour ridges and in woodlots.

**3.3 Rangeland management**

*3.3.1 Principles of rangeland management*

*3.2.3 Other strategies*

*3.2.2 Silages*

makes the product often quite expensive. Additionally, those of plant origin are also mostly based on staple food crops such as maize and soya bean, creating competition in use between humans and livestock.
