Bacteria Effect

There are approximately 1-10 billion bacteria in each milliliter (ml) of gut or contents. On high-forage diets, there are normally between 1 to 3 billion bacteria per ml of contents, and on high-grain diets, there are normally between 8 to 10 billion bacteria per ml of contents. The main reason for the difference in concentration are that high-forage diets contain more lignin, which can limit the surface area of available polysaccharides. And because there is a ‘lag time’ for the bacteria to attach to the forage particles. With high-grain diets, there is usually much more surface area for the bacteria to attach to, as grains contain very little lignin, and because the time it takes starch digesting bacteria to replicate is normally less than the time it takes cellulose digesting bacteria to replicate. Bacteria can replicate in 10 minutes to 2 hours, depending on the species. Any type of feed processing that increases the surface area available for bacterial attachment increases the number of bacteria digesting feed at any one time.

The major useful end-products of microbial fermentation are the volatile fatty acids (VFA), microbial protein, and B-vitamins. The three major VFA's are acetic (CH₃COOH), propionic (CH₃CH₂COOH) and butyric (CH₃CH₂CH₂COOH), which provide over 70% of the animal’s energy. Propionic acid is transported to the liver, converted to glucose, and used for energy. Acetic acid is used primarily in the production of milkfat, back fat, and seam fat, and butyric acid is used for energy production. As a result, maximizing the bacterial concentration, with any diet, should increase the energy production to the animal.

Specific research information can be found by clicking on the links below:

Wiedmeier et al.,  1987

Frumholtz et al.,  1989

Fondevila et al.,  1990

Beharka et al.,  1991

Newbold et al.,  1991

Newbold et al.,  1992

Campos-Montiel and Viniegra-Gonzalez,  1995

Kreikemeier and Varel,  1997

Beharka and Nagaraja,  1998