In recent years, in the Argentina Various protein and/or energy-rich by-products of the agricultural industry are evaluated. Among them, this stands out barley pellets or roots, This is waste from beer malt factories (malting houses).
The process begins with the germination of the barley grain (Hordeum vulgare) in large tanks with controlled temperature (36-38°C) and high humidity (+60%) for 7 days. When the grains germinate, they push out their first 3 to 4 roots (5 to 8 mm long), germination is stopped by a warm air stream of more than 70 °C emitted by turbines that dry them to a humidity of 4%. At this moment, the breakdown (hydrolysis) of the starch stops.
Strictly speaking, starch is broken down into various chemical compounds during the malting process. One of them is maltose and heat stops the process.
Finally, special rollers separate the “roots” from the grains. The grains “without roots” represent the malt itself, which, after grinding and fermentation with yeast, water and hops, ultimately forms beer.
The barley pellet consists of a) barley roots, b) broken or small grains and c) impurities (husks, sticks, etc.). The result of mixing these three fractions and after the pelletizing process with steam and pressure, the final product is the pellet or barley root.
Below is a brief summary of the role and values of the key nutritional parameters of the pellet or root. We will compare them to the values of “good” commercial, balanced foods.
The crude protein content of barley root is between 22 and 24%, although there are some products that can contain up to 30% protein. Commercially available balanced feeds for fattening (male or female) have a crude protein content between 12 and 14%, for dairy cows between 16 and 18% and for early weaned calves (meat) or artificially reared calves (milk) around 18 to 22%.
In other words, the rootstock with the lowest crude protein content (22%) is equal to or superior to the best commercially balanced food on the market.
The digestibility and convertible energy of the root are very high (75 to 78% or 2.7 to 2.8 Mcal ME/kg DM). A “good quality” commercially balanced feed, on the other hand, has a digestibility of 70 to 75% and a content of 2.5 to 2.7 Mcal ME/kg DM.
The starch (energy) content of the rootstock is between 28 and 30% of the total dry matter, depending on the proportion of broken and smaller whole grains it contains. In commercial balanced foods, the starch content can reach 26-28% on a dry basis, considering that they contain a high proportion of cereal grains (±30%), which is not common.
All nutritional parameters of barley root are excellent, both for high-yielding dairy cows and for artificial rearing, early weaning or various fattening stages (pasture or free range).
In practice and after numerous experimental works in different production systems, both meat and milk, with barley roots or pellets, this energy-protein supplement can be described as the most balanced food of “natural origin” that exists in the world.
The author is a doctor of veterinary science specializing in animal nutrition and managing director of the International Consulting Firm for Production and Nutrition of Cattle (Meat and Milk). afmayer56@yahoo.com.ar //resalancursos@gmail.com. www.nutriciondebovinos.ar
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