while baled silage tends to be used for beef cattle, sheep and horses. The advantages of silage as animal feed are several: During fermentation, the silage bacteria act on the cellulose and carbohydrates in the forage to produce volatile fatty acids (VFAs), such as acetic, propionic, lactic, and butyric acids. By lowering pH, these produce a hostile environment for competing bacteria that might cause spoilage. The VFAs thus act as natural preservatives, in the same way that the lactic acid in yogurt and cheese increases the preservability of what began as milk, or vinegar (dilute acetic acid) preserves pickled vegetables. This preservative action is particularly important during winter in temperate regions, when green forage is unavailable. When silage is prepared under optimal conditions, the modest acidity also has the effect of improving palatability and provides a dietary contrast for the animal. (However, excessive production of acetic and butyric acids can reduce palatability: the mix of bacteria is ideally chosen so as to maximize lactic acid production.) Several of the fermenting organisms produce vitamins: for example, lactobacillus species produce folic acid and vitamin B12. The fermentation process that produces VFA also yields energy that the bacteria use: some of the energy is released as heat. Silage is thus modestly lower in caloric content than the original forage, in the same way that yogurt has modestly fewer calories than milk. However, this loss of energy is offset by the preservation characteristics and improved digestibility of silage. History Using the same technique as the process for making sauerkraut, green fodder was preserved for animals in parts of Germany since the start of the 19th century. This gained the attention of French agriculturist Auguste Goffart of Sologne, near Orléans. He published a book in 1877 which described the experiences of preserving green crops in silos. Goffart's experience attracted considerable attention. The conditions of dairy farming in the United States suited the ensiling of green corn fodder, and was soon adopted by New England farmers. Francis Morris of Maryland prepared the first silage produced in America in 1876. The favourable results obtained in the US led to the introduction of the system in the United Kingdom, where Thomas Kirby first introduced the process for British dairy herds. The modern silage preserved with acid and by preventing contact with air was invented by Finnish academic and professor of chemistry Artturi Ilmari Virtanen. Virtanen was awarded the