Rumen Ecosystem:

Ruminants are kind of mammal which falls under Artiodactyla order. The word Ruminare is derived from Latin meaning chew again and again. They process the food in two steps. They digest plant materials such as grass by softening it with it’s stomach first and converts them in to semi digested mass and then masticate again. Semi digested mass is referred to as cud. Mastication of cud further or digestion of plant material further is referred to as ruminating. Ruminants are group of herbivorous animals mostly. The animals like goat, cows, sheep, deer, giraffes, elk and bison are ruminating.

Types of ruminants:

Morphological difference may be in their digestive systems, rumen size and others. The differences are because of different feeding habits. Based on the type and habit of feeding they are categorized as follows.

• Concentrate selectors
• Intermediate types and
• Grass eaters or roughage eaters.

Distribution: They are found plenty in all 5 continents and not in Antarctica and Australia. Native ruminants are nearly 75 million in number. Out of which around 3.5 million are domestic ruminants. Most of them are available in Europe countries. They can sustain vast range of climate starting from tropic to arctic. They are capable of habituating from plains to dense forests.

Feeding Habit: This type of feeding method is in practice because animals need take large amount of food in short period of time. Chewing of large amount of food in short period of time is not possible as it takes time for them to masticate and not safe in public place.

Processing of Food: Herbivorous animal’s stomach is divided in to four compartments to chew or process the intake food. Upper part of ruminant’s stomach stretches to form a pouch of larger size referred to as Rumen and smaller reticulum which is like honey comb. Bottom most part of the ruminants stomach has antechamber called as omasum and behind is true stomach that is abomasum.

Food intake is mixed with saliva in first two compartments namely the rumen and reticulum initially. The solid and liquid material gets separated here. Solid materials gets clumped together to form cud. Cud is also referred as bolus. Cud is chewed again in order to break down their particle size. The plant materials are rich in fiber content especially cellulose and hemi cellulose which are broken down to three fatty acids by microbial action like bacteria, protozoa, ciliates and fungi such as Neocallimastix as mentioned below.

• Ethanoic acid
• Propanoic acid and
• 3 – hydroxy butanoic acid

Other than plant materials, it can ferment proteins, pectin and sugars. The function of rumen and reticulum is almost similar and hence referred to as reticulorumen. They move back and forth to digest the intake food. The digested material come down to lower most part of reticulorumen chamber and ultimately passes in to omasum. Here water and other inorganic minerals are absorbed by blood stream. After absorption it passes in to true stomach, abomasum. The abomasum is similar to stomach. The digested food then moves into small intestine and glucose and nutrients are absorbed. Already digested food in reticulorumen gets digested again in small intestine. In a similar fashion ruminants ferment carbohydrates to fatty acids, CO₂ and H₂ takes place in large intestine.

Mutual Relationship:

Ruminants is not capable of producing cellulase. Hence they have established a mutual relationship with anaerobic micro organism which can produce cellulase. Cellulase break the covalent bond linkage of glucose residues of cellulose and glucose is released ultimately. The released glucose is then fermented to produce acids such as formate, acetate, propionate, butyrate and valerate. Produced organic acids act as a real energy sources for the ruminant. ATP produced during fermentation helps in growth of rumen microorganisms.