Livestock Digestion Objective 12.01-12.02: Describe the functions of the major parts of the digestive system for ruminants and non-ruminants.

Definition care of MedicineNet.com Accessory Organs What is an accessory organ? An organ that helps with digestion but is not part of the digestive tract. The accessory digestive organs are the tongue, salivary glands, pancreas, liver, and gallbladder. Definition care of MedicineNet.com http://www.medterms.com/script/main/art.asp?articlekey=25962

Accessory Digestive Organs An accessory organ of the digestive system is the salivary glands Secrete Saliva Help soften food Make food easier to swallow Start the digestion process

Accessory Digestive Organs The pancreas is an elongated, lobed-shaped organ. Made of two parts Exocrine Largest part Produces digestive juices Endocrine Produces insulin that goes into the blood

Accessory Digestive Organs The liver is another lobed-shaped organ that is responsible for purifying blood. Assists in the formation of blood Destroys exhausted red blood cells Remember: red blood cells deliver oxygen

Accessory Digestive Organs Gall Bladder Empties waste Secretes bile Bile- yellow liquid that aids in digestion of lipids Horses don’t have a gall bladder Bile is mainly to breakdown fats and horses typically ingest less fat than other animals

Digestive Organs

The Philosophy of Digestion (partial digestion review) What is digestion?? Conversion of “feedstuffs” into nutrients Last stage of digestion? Excreting unused food residues Fecal matter

The Philosophy of Digestion Digestive Processes Mechanical Chemical Microbial

The Philosophy of Digestion Mechanical Actions of Digestion Mastication Deglutition Regurgitation Motility Defecation

The Philosophy of Digestion Mastication The chewing of food Deglutition The act of swallowing Regurgitation Casting up undigested food from the stomach for chewing again (cud) Motility Process of contracting or shrinking (squeezing food through intestines etc) Defecation The elimination of fecal material from the rectum

The Philosophy of Digestion Microorganisms exist in the digestive compartments of ruminants They break down the cellulose of plant cell walls Also called roughages

The Philosophy of Digestion Roughages Cellulose of plant walls What makes up the majority of a ruminant’s diet Gives ruminants 60%-80% of their energy About 60%-90% of the digestion occurs in the rumen

The Philosophy of Digestion The hypothalamus glad is the gland that controls the animal’s appetite Three things that affect appetite Level of glucose in the blood Amount of feed in the stomach Environmental temperature

The Philosophy of Digestion Chewing food is also called… mastication/masticating This aids in the digestion process Breaks down and reduces the particle size of food Mixes food with saliva

The Philosophy of Digestion What is chewing “cud?” Occurs in ruminants A cow will chew it’s regurgitated food Why? This aids in digestion Roughages held in the rumen can be regurgitated and “re-chewed” to help digest

The Philosophy of Digestion Do poultry have teeth? NO! How do they grind their food with no teeth? The gizzard, an organ used to grind and crush food in chickens, turkeys, etc

The Philosophy of Digestion

The Philosophy of Digestion Enzymes are responsible for most chemical changes in the digestive process because they speed up the biochemical reactions of digestion A few enzymes to know Ptyalin Amylopsin Sucrase

The Philosophy of Digestion Enzymes Ptyalin Breaks down carbohydrates Amylopsin In the pancreas, breaks down starches Sucrase Another enzyme to help breakdown carbs

The Philosophy of Digestion Which compartment was called the “true stomach” of a ruminant? Abomasum Two enzymes in the Abomasum Pepsin Rennin Both are activated by hydrochloric acids and help break down proteins Ruminant!

The Philosophy of Digestion Ruminant!

The Philosophy of Digestion More Enzymes… Trypsin Chymotrypsin Carboxypeptidase Help break down proteins into amino acids, which are the final product in digestion

The Philosophy of Digestion …and More Enzymes… Lipase Breaks down fats Bile Secreted by the liver, breaks fats up Steapsin Secreted from the pancreas, finishes the break down of fats

The Philosophy of Digestion In animals, minerals are dissolved in the stomach The stomach contains hydrochloric acid Through absorption, digested nutrients can pass from the walls of the digestive tract into the blood

The Philosophy of Digestion Most absorption occurs Carnivores and Omnivores Small intestine Absorbed by villi in the small intestines Herbivores Large intestine

The Philosophy of Digestion More about Absorbing Lymph Absorbs fats Blood Absorbs carbs, proteins, water, and inorganic salts Digestion is complete only after absorption has made the nutrients available for other parts to use

Assignment Complete the rest of the notes by reviewing what you already know and using the packet that was passed out Most of these notes will serve as a review