Transcript Lecture 1
Concentrates Feeds & Nutrition AN S 336 Chapter 10 Introduction All biological processes require energy – Respiration, Temperature Regulation, Motor Control, etc. – Production Production – Parameters we as producers are seeking from our livestock – Lactation, growth, pregnancy, egg laying, etc. – Require large amounts of energy Introduction Production cont’d – Before energy is expended for production, energy requirements for routine body functions must be met – Therefore, producers must utilize a high energy ration when feeding • High caloric density and digestibility – A balanced high energy ration will allow for livestock to reach their genetic potential for production with a minimum amount of feed. Concentrates “Feeds that are high in nitrogen-free extract and total digestible nutrients (TDN) and low in crude fiber (less than 18%)” NFE – – – Term for organic material in a feedstuff for which there is no specific analysis. These include carbohydrates, pigments, and water soluble vitamins 100 – (% moisture + % crude fiber + % ash + % ether extract + % crude protein) Concentrates TDN – Sum of the digestible protein, digestible fiber, digestible nitrogen-free extract and digestible fat x 2.25 Concentrates Can be broken down into 2 categories: 1. Carbonaceous feeds 2. Nitrogenous feeds • Protein & protein supplements Function as a dietary energy supply. – Sugars, polysaccharides, fats and oils consisting primarily of the elements Carbon, Hydrogen, and Oxygen Concentrates When feeding concentrates, the cereal grains play the most important role. – Provide the bulk of the energy along with a large portion of the dietary protein. These grains are low in fiber, and are considered to be highly digestible by all of the livestock species – Nonruminants such as poultry and swine have the bulk of their ration consisting of these highly digestible cereal grains. Concentrates Cereal Grains – Seeds from cereal plants – Corn, Oats, Barley and Sorghum • Primary grains fed to livestock and poultry • Rice and Wheat are primarily consumed by humans – Millet, emmer, spelt and triticale are fed in small amounts. – Grains are very palatable to livestock with the exception of Rye. Feed Grains Fed to Livestock and Poultry (Million Tons) 160 140 120 100 Corn Sorghum Barley and Oats Total 80 60 40 20 0 1965 1970 1975 1980 1985 Corn (Zea mays) Most widely fed to livestock of all the cereal grains. Feeding value of other grains is compared to corn on a lb for lb basis. TDN around 90% for all species of livestock High in starch, Low in fiber Corn (Zea mays) Low in protein Used as a feedstuff for all animals Approximately 25% of all corn production is fed to hogs. Constitutes about 81% of all grains fed to livestock in the U.S. Oats (Avena sativa) Very palatable, and considered to be an excellent conditioning feed High in protein when compared to the other grains Best balance of amino acids of the cereal grains TDN approximately 75% Compared with corn, oats have a feeding value of 70-80% on a lb for lb basis. Oats (Avena sativa) Oats are considered to be an excellent feed for all livestock especially horses and breeding stock for most species. Barley (Hordeum vulgare) Palatable feed Contains more protein, lysine and fiber than corn TDN approximately 82% Compared to corn, barley has a 90-95% feeding value on a lb for lb basis Barley (Hordeum vulgare) A large portion of the barley grown in the U.S. is used for brewing and distilling. As a feedstuff: – An excellent source of energy for Beef and Dairy cattle – A good source of fiber for poultry and swine. – Barley should be ground or somehow processed prior to feeding for all species of livestock Sorghum (Sorghum vulgare) Sorghum is increasing in importance as a feedstuff, and currently ranks second behind corn. Almost exclusively a feed grain in the United States. Sorghum has a TDN value of 75% When compared to corn, sorghum has a feeding value of 85-95% Sorghum (Sorghum vulgare) Approx. 98% of the sorghum grain used in the U.S. goes into livestock and poultry rations Sorghum constitutes 6-8% of cereal grains fed to livestock Sorghum needs to be processed in some way prior to feeding Minor Cereal Grains Millet – TDN approximately 70% – May be used as a feed for livestock and poultry Emmer – TDN approx. 77% – Minor grain crop similar to barley and oats. Minor Cereal Grains Spelt – TDN approx 75% – Principally used as a livestock feed. – Grain has no milling value. Triticale – Hybrid of durum wheat and rye – TDN of 84% – Difficult to use for livestock because of high costs Digestion The consumption of grain in a ration results in the acquisition of carbohydrates or more simply put starch which the body can use for energy for the biological processes mentioned earlier. Digestion and absorption of these starches takes place in different places in the different types of livestock. Digestion Ruminants vs. Non-Ruminants – Ruminant animals digest starches in a different way than do non-ruminants – In the non-ruminant starches are broken down and absorbed in the small intestine – This is accomplished by a series of enzymes (amylase, trypsin, etc.) which breaks the starch down into a 6 carbon sugar known as glucose. • Glucose is the sugar from which the body produces ATP (useable energy) Digestion In the ruminant, the starches first reach the rumen. Here, the starches undergo microbial fermentation and are converted into Volatile Fatty Acids (VFAs) These VFAs are short chain carbon molecules 2,3,4 carbon atoms long which are absorbed into the blood stream through the rumen wall. Digestion Once in the blood stream, these carbon chains can enter the cells and directly into the Citric Acid Cycle to be converted into ATP. Not all starch will be digested by the rumen. Some will escape and enter the abomasum (true stomach) and small intestine. Once this occurs, digestion and absorption will occur in the same manner as it did in the nonruminant. Problems The use of concentrates gives the producer a way to boost production levels through higher levels of energy consumed. These grains can be used to bolster high levels of production, or to compensate for animals which are unable to use forages effectively. They are not without their problems though. Problems High-concentrate rations can cause acidosis and para-keratosis of the rumen. – Ruminants need some roughage to stimulate the growth of rumen papillae – This can be accomplished by rolling or coarse grinding the grain. – Most feedlot finishing rations contain some source of forage (10-15% of the ration) Problems Some grains need to be processed before they can be fed – Determined by the type of grain and the type of animal being fed. Grains are more expensive than most forages on a weight basis – When comparing the two the energy content, digestibility and nutrient density must be considered on a per unit of feed basis Problems Grains are very deficient in calcium and certain vitamins – Most grains contain less than .1% calcium and adequate amounts of phosphorous – Vitamin A is low in all grains except for fresh yellow corn