Digestive System

DOLOR SET AMET

ANIMAL ANATOMY

CHAPTER 1

Digestive System

4 COMPARTMENTS

Many people think that ruminant digestive systems have 4 stomachs, but they actually have 4 compartments.

Those 4 compartments are the rumen, the reticulum, the omasum, and the abomasum.

DIGESTIVE SYSTEM

Ruminants The rumen is the largest compartment and has the nick-name “The Fermentation Vat”. It makes up 80% of the stom-achs capacity. It can partially break down food with millions of bacteria and microorganisms. The rumen is where food is regurgitated, then re-chewed in the form of “cud” and re-swallowed for further digestion.

The reticulum is nicknamed the “Honeycomb”, the inner walls are lined with membranes that are divided into honey-comb like compartments. It acts as a collection for metal ob-jects such as nails and wires. This is how animals are able to eat objects such as metal cans.

A rumen magnet is inserted orally to the rumen to pre-vent or treat a disease known as hardware disease. Hardware disease usually occurs when an animal has swallowed a sharp metal object causing irritation or cut in the stomach. The mag-net will hopefully help keep the object contained so the hole can be repaired. In some cases surgery is necessary.

The omasum absorbs water and helps decrease the size of food particles. It is nicknamed “Manyplies” or Butchers Bible” . It contains many little folds of tissue that line the interior.

The abomasum is nicknamed the “True Stomach”. It functions similar to a non-ruminant stomach and secretes di-gestive enzymes. It functions as a digestive unit of calves until rumination begins several months later.

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DIGESTIVE SYSTEM

Calves Digestive Developement

A calf is not born with a functioning ruminant digestive sys-tem, it must be developed over time with proper nutrition. Calves could technically be considered non-ruminant until they have properly developed the ru-men. The first few months are critical in calves for growth, development, and too avoid digestive problems later.

At early stages, such as nursing, the rumen is not the largest compartment of the stomach and only acts as another part of the esophagus, pass-ing milk to the other chambers.

The rumen officially begins to develop a few weeks after the calf has begun to start eating forages such as hay and grass. If calves do not get the proper nutrition, they can develop seri-ous digestive diseases and problems later on and delayed growth.

Another very important part of the rumen development is wa-ter. Milk and other liquids do not help with rumen develop-ment they only pass through to other chambers. Water helps bacteria needed for fermentation.

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Non-ruminant animals are often referred to as “mono-gastric” because they only have one chamber in their stomach. Food is passed through the mouth to the esophagus to a single com-partment stomach. Some common mono-gastric animals are pigs, cats, and dogs. The stomach breaks down food with a muscular movement and digestive juices. Digestive juices help break down fats and pro-teins. The small intes-tine is where most diges-tion and absorption of proteins, carbohydrates, and lipids happens. Un-digested food is passed through the small intes-tine to the large intes-tine. This is where water is absorbed and mucus is added to aid the passing materials through the large intestine.

Cecal Fermenters are very similar to mono-gastric ani-mals and only have a single chambered stomach. The only difference is they are able to digest roughages like rumi-nant animals. Horses are the most common known of cecal fermenters. They have a large cecum which allows them to consume roughages such as hay. There is a bacteria pre-sent in the cecum to help di-gest roughages.

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DIGESTIVE SYSTEM

Non-Ruminant “Mono-gastric” and Cecal Fermenters

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DIGESTIVE SYSTEM

Process

There are five processes to digestion. They are me-chanical, peristalsis, chemical, absorption, and metabolism.

Digestion begins at the mouth when food is chewed, broken down to smaller pieces, and then swallowed. This is the mechanical process.

Peristalsis is a wavelike moment that causes food to move through the digestive tract which is caused by a muscular contraction.

The chemical process involves the enzymes and acids in your body which reduces food size and changes particles to useful forms for animals. While most of this occurs in the stomach

and small intestines, some occurs in the mouth with the help of salvia.

Absorption is when the nutrients move from the digestive tract to the bloodstream making the nutrients usable for animals. It takes place mostly in the small intestine in mono-gastric systems, in ruminant some occurs in the rumen.

The last process is metabolism, this removes nutrients from the blood-stream and allows the different or-gans to use it. This process is respon-sible for bone, muscle, fat, skin, and hair growth. It helps maintain body temperature and proper functioning organs.

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