Digestion In Ruminants - Structure, Function, Process,Types, Digestion, & Facts

What Are Ruminants?

Ruminants are herbivorous mammals which have three-chambered stomachs intended for the digestion of plant tissues. These include animals including cattle, sheep, goats, and deer. This is important as it shows how such animals can effectively break down plant matter to enable the human body to be provided with vital nutrients through microbial fermentation and the process of regurgitating and chewing the cud.

Key Characteristics of Ruminants

The characteristics of ruminants are listed below-

Physical Characteristics

• Ruminants have a complex and specialised stomach which contains four compartments including the rumen, reticulum, omasum, and abomasum.

• They possess dental pads and do not have upper incisors.

Behavioural Characteristics

• There are several subgroups of mammals, some of which include ruminants, which feed on grasses and other parts of plants

• This means they spend most of their time chewing the cud (rumination).

• Many of them are herding animals.

Compartments of the Ruminant Stomach

The four compartments of the stomach in ruminants are:

Rumen

• Structure and Function: The food before entering the rumen is partially or even completely digested. This serves to hold and process a material which could be plant matter when ingested, mixed with saliva and fermented by microbes.

• Microbial Fermentation: It contains numerous bacteria, protozoa and fungi, which ferment the dietary fibres into simpler molecules, and volatile fatty acids.

Reticulum

• Structure and Function: The second chamber is called the reticulum which has a honeycomb-like structure. It collaborates with the rumen to sort large parts from small ones and helps to spit a cud to chew it again.

• Role in Regurgitation and Cud Chewing: It acts almost similarly to a sack that is used in rumination in which food is regurgitated before being chewed for a second time to improve its digestion.

Omasum

• Structure and Function: The omasum or manyplies has a large number of ridges or leaves for absorption activities due to the large surface area demanded by the organ.

• Role in Water and Nutrient Absorption: Regarding the role of the duodenum, it serves to absorb water to thicken the digest, thus decreasing its bulk and at the same time, increasing the nutrient density before the material enters the abomasum.

Abomasum (True Stomach)

• Structure and Function: The abomasum on the other hand the fourth stomach chamber also known as the true stomach where enzymatic digestion happens. It discharges other juices by which more enzymes are released to continue digesting proteins.

• Similarities to a Monogastric Stomach: Abomasum is the organ in monogastric animals which works like the stomach in that they both are responsible for the digestion of protein and also the preparation of the food for absorption in the intestines.

Digestive Process in Ruminants

The digestive process in ruminants is listed below-

Ingestion and Initial Chewing

• Food Intake and Partial Chewing: The ruminants start the digestion process by grazing. The initial chewing is roughly done because its main function is to increase the size of food particles that are to be digested further.

Regurgitation and Re-Chewing (Rumination)

• Cud Formation and Re-chewing: The food is swallowed and partially digested in the rumen then the chews and brings it back to the mouth. The ruminant chews again the cud to process it to an even finer state by mixing it together with saliva for digestion.

• Benefits of Rumination: This process enhances the effectiveness of breaking down fibrous plant material, boosts the rate of microbial fermentation and thus raises the overall effectiveness of nutrient absorption.

Microbial Fermentation

• Breakdown of Cellulose and Fiber: In the rumen bacteria, protozoa and fungi decompose cellulose and fibre into simpler substances in the rumen

• Production of Volatile Fatty Acids (VFAs): This fermentation yields short-chain fatty acids, acetate, propionate and butyrate which are then consumed as the main energy source.

• Synthesis of Microbial Protein: Microbes also produce proteins which are later used by ruminants for amino acids, that are considered important.

Absorption

• Absorption of VFAs in the Rumen: VFAs synthesised in the rumen are absorbed through the wall of the digestive organ with the help of blood vessels to maintain its energy.

• Absorption of Water and Nutrients in the Omasum: The omasum serves in the soaking of water and consolidation of nutrients, thus the volume of the digester is to some extent reduced and nutrient uptake is increased.

True Digestion and Intestinal Absorption

• Secretion of Digestive Enzymes: The abomasum produces hydrochloric acid and enzymes to digest proteins and other constituents.

• Breakdown and Absorption in the Small Intestine: Enzymatic digestion goes on in the small intestine where nutrients are even more digested and assimilated into the bloodstream.

• Large Intestine: Large intestine absorbs water and electrolytes and the waste products in the remaining foods are transported to be excreted.

Comparison: Ruminants vs Non-Ruminants

The difference between ruminants and non-ruminants are:

Digestion in Ruminants NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Compartment of the ruminant stomach

• Digestion in Ruminants

Practice Questions for NEET

Q1. The esophagus opens in which part of the stomach?

1. Tiger

2. Horse

3. Lion

4. Human Beings

Correct answer: 2) Horse

Explanation:

The horse is known for its remarkably long small intestine, which aids in the digestion and absorption of nutrients from the plant-based diet that horses consume. The length of the small intestine in horses allows for thorough digestion and extraction of nutrients from the ingested food before reaching the large intestine. This adaptation is essential for herbivorous animals like horses to maximize nutrient absorption from the fibrous plant material they consume.

Hence, the correct answer is option 2) Horse.

Q2. The trigger for activation of the toxin of Bacillus thuringiensis is:

1. Acidic pH of stomach

2. High-temperature

3. Alkaline pH of gut

4. Mechanical action in the insect gut

Correct answer: 3) Alkaline pH of gut

Explanation:

The alkaline pH of the gut of insects converts inactive protoxin into active toxin. This kills the insect. The alkaline pH in the gut of insects activates the protoxin produced by Bacillus thuringiensis, converting it into its toxic form. The activated toxin binds to receptors on the insect's gut cells, disrupting the digestive system. This results in the insect's inability to process food, leading to starvation and death. As a result, Bacillus thuringiensis serves as an effective biopesticide for controlling insect populations.

Hence, the correct answer is option 3) Alkaline pH of the gut.

Q3. Assertion: The rumen of ruminants contains billions of microorganisms.

Reason: These microorganisms help break down cellulose and other tough plant material in the rumen.

1. Assertion and reason are both true, and reason is a correct explanation of assertion.

2. Both assertion and reason are accurate, but reason does not correctly explain the assertion.

3. The assertion is correct, but the reasoning is incorrect.

4. Both the assertion and reason are incorrect.

Correct answer: 1) Assertion and reason are both true, and reason is a correct explanation of assertion.

Explanation:

This assertion and reason are both true. The rumen of ruminants is a large fermentation chamber that houses billions of microorganisms, including bacteria, protozoa, and fungi. These microorganisms play a crucial role in the digestion of plant material, breaking down cellulose and other complex carbohydrates into simpler compounds that can be absorbed by the animal. The microorganisms also produce important nutrients, such as B vitamins and essential amino acids, that the animal can utilize.

Therefore, the reason explains why the assertion is true, and both the assertion and the reason are accurate.

Hence, the correct answer is option 1) Assertion and reason are both true, and reason is a correct explanation of assertion.

Also Read:

• MCQs on Ruminant Digestive System

• Pancreas Function in Human Body

• Intestinal Glands

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