Senwes Scenario August/September 2018 | Page 16

AGRICULTURAL Feed sources on a grain farm What is the nutritional value and use for livestock production? In the previous article regarding Livestock + grain = a sensible choice, we referred to different sources of feed which can typically be produced on a grain farm and used for livestock production, specifically beef production. What is the feeding value of these different sources of feed for animal production?  By Dr Kobus Swart Animal Nutritionist I rrespective of the production system used, the primary nutrients required by animals for production are energy, protein and minerals. On a grain farm the feed produced provides energy in the form of grains which are high in starch and roughage which is high in fiber. Energy remains the most important and most expensive feed component. That is why a grain farm has a competitive advantage in respect of animal produc- tion. 14 SENWES SCENARIO | SPRING 2018 DIGESTIBILITY MAKES THE DIFFERENCE The digestibility of feeds sources differs from each other and which is important to consider. The biochemical composition of the feed determines how effective energy is released and made available to the animal for production. The higher the fiber content (NDF), the slower the feed will be digested, the lower the daily voluntary feed and energy intake and the lower the daily production (growth) will be. Ruminants can digest crop residue like Maize Stover or Wheat Straw produced on a grain farm but, however, this source can only provide approximately 50% of the metabolizable energy which is in Maize or Hominy Chop per kilogram available to the animal. Although not produced on farm, Hominy Chop is mentioned as a feed source since it is usually available as a milling product in grain producing areas. On the other hand, these high-starch and high energy feeds can course metabolic disturbances, like acidosis, if fed in large quantities without adequate fiber and in a nutrient balanced feed. FEEDS MUST BE NUTRITIONALLY BALANCED Adequate protein, nitrogen and minerals must be provided to balance the feed and