The Biology of the Goat Animations


Rumen microbes

The rumen contains a population of very specific micro-organisms.
Bacteria, protozoa and fungi are necessary for the digestion of cellulose
and other plant materials since animals do not have the enzymes
to digest this food source on their own.

rumen

The products released from digestion of plant materials by rumen microbes
supplies the goat with essential nutrients.

In one milliliter (1 ml) of the contents of a mature rumen there are about
1 million protozoa, 10's of billions of bacteria and thousands of fungi.

rumen

Protozoa are large, single-celled organisms. The species found in the rumen live
in no other environment and cannot survive outside the rumen for very long.
They come in different shapes and sizes.
They usually have microscopic hairs called cilia which help them move or push food toward their mouth.

Protozoa can only be established in the rumen by direct contact with the mouth or saliva of another goat.

rumen

Protozoa are the simplest form of animal life.
They have a skin, a mouth and digestive tract.
Other organs (vacuoles) control gases, and liquid and solid waste products.
They reproduce usually by division.

rumen

Rumen protozoa are facultative anaerobes, meaning that they can survive without oxygen
but they are able to use the low levels of oxygen that enters the rumen.
This helps to maintain an anaerobic condition in the rumen which is important
for the survival of rumen bacteria.
Protozoa ingest and store starch granules.
This helps to prevent starch digesting bacteria from causing high acid levels.
Protozoa eat bacteria as a source of nutrients preventing a harmful bacterial overgrowth.

Rumen Bacteria

rumen

Rumen bacteria play the major role in fermentation by converting cellulose
from plants into usable energy products for the goat.

There are many different kinds of bacteria which are found only in the rumen.
Some rumen bacterial species also digest starch, sugars, and other plant materials.

Some are able to utilize gases and the acidic by-products of other rumen bacteria.
Some bacteria even attack and destroy competing bacteria.

rumen

Rumen bacteria are strictly anaerobic (obligate anaerobes) which means that oxygen is toxic to them.
For this reason they cannot survive outside of the rumen environment.
Like protozoa, rumen bacteria are passed from goat to goat.
Bacteria produce all of the necessary B vitamins for the goat.
Large amounts of bacteria end up in the abomasum.
Goats, like all ruminants, secrete an enzyme in the abomasum called lysozyme which digests bacteria,
supplying 90% of the essential amino acids for the goat.

Rumen Fungi

The rumen can contain several different types of primitive fungi.
Fungi need nutrition and vitamins that they receive from rumen bacteria.
The action of the rhizoids penetrating plant material weaken plant cell walls
so that bacteria can more easily degrade and breakdown cellulose.
Fungi also contribute to fermentation.

A typical life cycle of a rumen fungi (Neocallismastix species.

Zoospore is attracted to the type of plant tissue that surrounds flowers and seeds.

rumen

The zoospore becomes encysted then germinates and forms a single rhizoid.

rumen

The rhizoid system grows and forms long branches.
Rhizoids secrete enzymes which break down compounds in the plant stem
and is then absorbed by the fungi.

rumen

When certain plant types are ingested a sporangium develops.
The nucleus divides.

rumen

Zoospores mature then are released to start the cycle again.

rumen