Strategic nutrient supplementation of free-ranging goats

Abstract

This paper provides an insight to nutritional limitations of forages and other feed resources and the use of supplementation technology by small farmers to optimize production potential of goats in semiarid range environments. In developing countries, the potential for goat meat production is limited by many environmental and nutritional factors. Free-ranging goats can select their diet from a complex variety of available native plant species. Forage quality and availability are reduced during winter and dry seasons of the year, affecting nutrient intake. Furthermore, the presence of plant secondary metabolites (PSM) in shrub species reduces the availability of energy, increasing the demand for glucose. Supplementation is required to mitigate both, nutrient deficiencies and the effect of PSM toxicity. Supplementation options include leguminous fodders that can serve as good protein and energy sources. However, these fodders need to be irrigated for optimum forage production. Cactus, which requires very little water and is frequently used in some developing countries as feed supplement for ruminants during periods of severe drought, has the disadvantage of high fibre and ash contents, and therefore, low energy and protein densities. Supplementation can also include energy sources such as molasses, cereal grains and byproducts, oilseeds and protein meals, minerals and vitamin A. Feed additives such as ionophores and polyethylene glycol (PEG) still need more evaluation under range conditions. Low-level (0.2–0.4% of body weight) cost-efficient high protein and mineral supplements should be considered carefully. Supplementation should be specific, considering the protein content and mineral profiles of forages in each region. Mineral and protein supplementation of goats consuming high fibre-low protein forages, generally improve intake and performance. Hand-crafted multi-nutrient blocks based on molasses and urea, can stimulate rumen fermentation and supply nutrients needed to complement deficiencies of goats consuming low quality forages. These bocks would require certain degree of compaction and the inclusion of lime (calcium oxide) that reacts with molasses will aid in hardness to restrict intake. They can be transported and managed easily and control supplement intake, while reducing the need of salt as intake regulator and the risk of urea toxicity. Technology transfer to producers should emphasis the use of cost effective and specific nutrient supplementation technology to optimize growth and reproduction of range goats.