Ruminant Animals: A Comprehensive Guide

November 10, 2023December 4, 2023 Agric4Profits

The ruminant animals have a digestive system that is quite different from the monogatstrict animals. In fact the nature of the ruminant digestion process from the basis of what you will be studying in subsequent units where feeds materials and the feeding of sheep/goats and cattle are treated.

This article attempts to give a brief overview of the digestion process in ruminants animals. The difference in the process of digestion as well as the anatomied difference of the stomach of young ruminants have been outlines.

The presence of microorganisms in the rumen and their advantages or disadvantages to the host animal has been treated.

Digestion in Ruminant Animals

The rumen consists of pillars, rhythmic contraction of these pillars causes the rumen to contract and expand leading to a mixing of its contents. The rumen content is made up of a more liquid part at the bottom and a dense floating “raft” of solid, mainly fibrous materials.

It is this dense floating fibrous materials that the ruminant is seen further chewing (regurgitating). The act of regurgitation reduces the particle size of the fibrous materials there by increasing surface area for attack by the micro organisms in the rumen and reticulum.

1. Carbohydrate Digestion in the Rumen

The first micro-organism to attack food in the rumen is the fungi. Secrets enzymes that break down the surrounding fibres thereby reducing the physical strength of food particles and allow the entry of bacteria and protozoa.

The rumen is an anaerobic (oxygen free) environment under this condition the protozoa and bacteria secrete enzymes that can breakdown the B-linkage in forages and 1 other fibrous feed materials to produce pyruvic acid (pyruvate) which is further broken down (Oxidized) to produce volatile fatty acid (VFA).

The major fatty acids produce in the rumen are acetil acid, propionic acid and butyric acids. Others are valeric, and iso-butyric obtained from micrsial metabolism of protein. The VFA produced from the incomplete digestion of carbohydrate is absorbed through the rumen wall.

You should note that the energy produced during an aerobic fermentation is lower than what is produced under aerobic (dependent on oxygen) fermentation where the end product is carbon dioxide and water.

2. Protein Digestion in the Rumen

Some of the protein consumed by the ruminants may escape microbial fermentation in the rumen and pass unchanged into the abomasums.

Some of these proteins that get into the abomasums which can be digested by the normal enzymic digestion that takes place in the abomasums is extremely important in ruminant nutrition and has been given various names such as “By Pass Protein”, “Rumen Escape Protein” Rumen Undergraduate Protein (RUP)”.

The fraction of dietary proteins that is degraded in the rumen is referred to as rumen degraded protein (RDP). The end product of the digestion of RDP are simple amino acids, ammarta and some urea.

Digestion leaves the reticula – rumen through the retuicula – omasa orfifice to the omasum. The major role of the omasum in the absorption of urge volume of water coming together with the digesta.

3. Digestion In The Hind-Gut

Once the digesta enters the abomasums it is subjected to a series of changes through the action of enzymes that is similar to what happens in the simple stomach of the monogastric animal.

4. Digestion In The Young Ruminant

Ruminants are not born with range rumen. At birth, the rumen and Reticulum together account for about 30% of the volume of the 4 chambers,

By the age of 2 months this would have increased to about 70% and in mature cow the rumen and reticulum together occupy 85% of the volume. The abomasums on the other hand will have reduced from 70% to 7% of the volume.

In the young ruminants, feeding solely on the dan’s milk the fore-gut digestion does not occur. Rather milk is passed straight from the oesophagus to the rumen through the oesophageal groove.

This groove is formed as a result of a reflected action of the young ruminant which initiated by the act of suckling. This is an important aspect of the nutrition of a young calf as milk is not subjected to microbial fermentation which reduces the quality of milk.

As the animal matures and begins to nibble on grasses and other solid feed materials however, the animal losses this ability to close the groove and the rumen begin to develop to what eventually obtains in the adult.

Advantages of Ruminant Digestion Process

The presence of the microbial population in the rumen has a marked effect on the nutrient metabolism of the host. The microbial population allows for effective utilization of fibrous materials particularly cellulose through the action of protozoa and bacterial that can break down the b-linkage in cellulose.

Micro-organism are also to make use of certain feed components to synthesis other essential nutrients. Example of this is the use of pan protein Nitrogen (NPN) by ruminants to synthesis cellular proteins.This reduces the dependence of high quality protein by ruminants and allow the use of compounds like urea to serve as protein use.

Micro-organism in the rumen can produce all B-complex vitamin. As a result they do not need to be supplied in the feed. This is with the exception of vitamins A.D and E.

Disadvantages of Ruminant Digestion Process

Most dietary protein are degraded to ammonia then to microbial protein. In some cases the microbial protein is lower in quality compared to the dietary protein. This therefore results in wastage.

Simple sugars such as glucose and starches are completely broken down to volatile fatty acids. While these acids are readily used by the animal tissues, they are used less efficiently for energy than the original carbohydrates.

During the fermentation process, as much as 4-10% of the energy consumed is converted to methanic and hydrogen gasses which the animal cannot utilize and is wasted as a result of microbial fermentation.

In conclusion, the digestion process in a ruminant animal is a complex activity involving the breakdown of fibrous materials by micro-organism leaving in the rumen in a symbiotic relationship with the animal.

It is therefore not necessary to provide ruminants with all the feed nutrients because some of it can be synthesis through the action of these micro-organisms.

Ruminant Animals: A Comprehensive Guide