Fermentation of Fodder

a biological method of preparing fodder that increases its nutritional value and improves its taste and dietetic qualities. It is used mainly in swine breeding.

Grain fodder that is rich in carbohydrates (barley, corn, oats, and bran), and sometimes root crops and mixtures of grain and root crops, are fermented. During the process there is rapid multiplication of the yeasts, which is accompanied by alcoholic fermentation. Lactate bacteria, whose metabolic products are lactic, acetic, formic, and some other volatile acids, reproduce at the same time. As a result, the pH of the fodder is raised to 3.8-4.2, thereby preventing the development of putrefactive bacteria. Yeasts are capable of synthesizing protein from simple nitrogen compounds, which increases the total amount of protein in the fodder. The bacterial protein of yeasts is similar in composition to the proteins of animal origin, and it contains a large quantity of irreplaceable amino acids. The digestibility of protein is also increased. In addition, the fodder becomes enriched with B-complex vitamins and enzymes. All these qualitative changes in the fodder have a beneficial effect on the appetite, health, reproductive functions, and productivity of the animals.

A culture of baker’s yeast fungi is used to ferment fodder. Yeasts of the species Anthomyces Reukauffii, which are present on the surface of grains, also participate in the fermentation. The rate at which the yeasts multiply depends on the presence of nutrients in the material being fermented, the degree of pulverization and moisture content of the fodder, the temperature, and the aeration conditions. Yeast fungi multiply and grow quickly in a medium rich in soluble carbohydrates, nitrogenous compounds, and minerals. The optimum temperature is 20°-25°C. The fodder should have the consistency of thick gruel. The medium is aerated by mixing. The fodder is fermented with or without leaven. To prepare the leaven, the yeasts are first added to a small batch of fodder mixed with warm water. After 4-6 hours the remaining fodder is added to the ready leaven and then kept for 3 hours. In the nonleaven method, the yeasts are mixed immediately with all the fodder; fermentation continues for 6-9 hours. The maximum amount of fermented fodder given daily to boars, sows, piglets 2 months old and older, as well as to young animals that are being fattened, is about 50 percent of the ration. Ten days before farrowing the amount of fodder given the sows is reduced or eliminated completely.