Anatomy of Livestock Species Flashcards
How is digestion achieved?
A combination of Physical/Mechanical, Chemical, Enzymatic, and Microbial actions.
What are the digestive system types?
Monogastric and Ruminant
What types of animals are monogastric?
Swine and Equine
What types of animals are ruminants?
Cattle, sheep, goats
What makes horses special when it comes to being monogastric?
they are monogastric herbivores, or non-ruminant herbivores
How many stomachs does a ruminant have?
1, but that stomach has 4 compartments
What are the 4 different compartments of the ruminant stomach?
Rumen, Reticulum, Omasum, and Abomasum
Which type of digestion is the fastest, and why?
Monogastric, different feeds have different digestibilities, and rumination takes a lot of time.
What are the functions of the mouth?
take in food, taste, chew, and mix the food with saliva
What is mastication?
the physical reduction of feed to increase surface area
What are the adaptations related to mastication?
Carnivores have incisors made for tearing and little chewing, herbivores have specialized molars made for chewing and grinding, horses grind in a circular motion with their molars, sheep and cattle have dental pads and molars on the bottom, molars roll and crush turgid and brittle food.
What are the three pairs of salivary glands?
Parotid - contains secretory proteins and produces zymogen, located in front of ears.
Submaxillary - produces seromucous fraction, located inside lower jaw.
Sublingual - contains mucous secretory portions, located underneath the tongue.
serous gland secretions are sometimes rich in What?
proteins and water
Mucous gland secretions are sometimes rich in what?
glycoproteins and water
Saliva is made up of what?
99% water
and 1% mucin, inorganic salts, alphaamalayse, and alysazyme
Which animals lack amalyse?
horses, cats, and dogs
Which animal has amalyse with low activity?
Pigs
What do salivary glands secrete?
water, mucin, bicarbonate salts, and amalyase
Water
moistens the feed and aids in mechanisms
Mucin
lubrication aid for swallowing
Bicarbonate salts (sodium bicarbonate)
act as a buffer to regulate stomach pH
Amylase
the digestive enzyme that starts to break down simple sugars in the feed
Swine differ from ruminants in that…
they secrete salivary amylase while cows do not secrete enzymes, but provide a source of N,P, and K
Esophagus
A muscular tube that connects the mouth and stomach, and uses peristaltic waves to move ingested material
horses esophagus
have one-way peristaltic waves, a very strong sphincter, and the tube connects at an oblique angle, so regurgitation is nearly impossible
Ruminants esophagus
two-way movement that allows rumination to occur easily, so regurgitation is very easy
Cardia
the sphincter at the junction of the esophagus and stomach, which controls the passage of ingesta into or out of the stomach
Esophageal region
non-glandular area surrounding the cardia
Cardiac gland region
(1/3 of stomachs surface) contains cells that produce primarily viscous mucous that protects the stomach lining against acid
fundic gland region
contains cells that protect the gastric secretions need for the initial stages of digestion
Parietal cells in fundic gland
produce hydrochloric acid
chief cells in fundic gland
produce enzymes/precursors of enzymes and controls the passage of food from the stomach to the small intestine
Pyloric gland region
located before the entrance to the small intestine, contains cells that produce mucous and some proteolytic enzymes
Plyorous
the sphincter at the beginning of the small intestine which controls the passage of chyme out of the stomach
The monogastric stomach
A hollow, pear-shaped, muscular digestion organ that stores ingested food and is very acidic with a pH of around 2 or 3. Muscular movements cause a physical breakdown, secretes juices, and regulates gastric secretions.
What are the digestive juices of the monogastric stomach?
Gastrin, Hydrochloric acid, Pepsinogen, Rennin (chymosin), and mucous.
how much does each compartment take up in the ruminant stomach?
Reticulum - 5% Rumen - 80% Omasum - 7-8% Abomasum - 8-9%
Reticulum
“honeycomb - grinding, transfer, trap objects, part of nd not completely separate from the rumen, walls are lined with a mucous membrane containing many intersecting rides that are the reason for the honeycomb-like surface, no enzymes are secreted, Reticular groove, plays a crucial role in stomach contractions, responsible for regurgitation and eructation, and even controls digestea passing to the omasum.
hardware disease
when cows eat objects that cannot pass or can puncture through the reticular wall and puncture the pericardial wall of the heart and ultimately cause death,
Reticular groove
in young ruminants, transfer milk from esophagus to omasum and abomasum, but non-functional after weaning, this keeps the mother’s milk from being mixed with microorganisms and broken down.
Rumen and its functions
Fermentation vat or paunch are its nicknames largest compartment that holds over 40 gallons and could nearly fill the entire left side of the abdominal cavity, a large, hollow, muscular compartment which extends from the diaphragm to the pelvis, walls are covered in papillae for absorption since no enzymes are secreted. It is used for storage, soaking, physical mixing, breakdown, physical contraction, Fermentation chamber (since it provides the ideal environment for microbial activity), Microbial digestion of feed (bacteria, Protozoa, And Fungi), Produce Volatile Fatty Acids (VFA’s), and methane. The bottom is fluid, and fiber floats to the top like a raft, then the microorganisms destroy the raft.
What are the VFA’s
Acetate, Proportionate, and butyrate
What are the 4 steps of rumination?
regurgitation, remastication, resalavation, and Reswallowing
the 4 r’s
where does fermentation occur?
in the rumen in primarily in the reticulum (reticulorumen)
What are the products of fermentation?
Acetate, Proportionate, butyrate, Gas(methane, and carbon dioxide), Eructation (belching/releasing of gas), heat, microbial crude proteins, B vitamins, and Vitamin k.
high forage vs. high grain
the makeup of microbial organisms depends on diet, so a diet should be changed slowly over the course of about 10 days, microorganisms numbers peak 2-3 hours after a high grain diet, and 4-5 hours after a high forage diet.
what is propionate?
gluconeogenic (glucose=sugar)
What are Acetate and butyrate?
lipogenic (lipids=fat)
Forage diet percents
65% acetate
25% propionate
10% butyrate
Grain diet percents
50% acetate
40% propionate
10% butyrate
types of microbes in fermentation
bacteria, protozoa, and fungi
Favorable conditions for fermentation
a constant temperature of ~102 degrees f, motility (mixing of digestea), Continuous nutrient supply, constant pH of 5.5-7.0, end producers are removed, and no oxygen (anaerobic).
Microbes for fermentation and their classifications
cellulolytic digests cellulose, amylolytic digests starch, Hemicellulolytic digests hemicellulose, proteolytic digests proteins, sugar utilizing uses monosaccharides and disaccharides, acid utilizing uses lactic, succinic, and malic acids, vitamin synthesizers, and methane producers.
Eructation
belching of gas and production of gas
Belching of gas
microbial fermentation in the rumen produces large amounts of CO2 and Methane, if the gasses are not released, the animal will bloat, which can result in death.
Gas production
65% CO2, 25% CH4, and 7% N2 with some O2, H2, and H2S. This is the cause for energetic inefficiency compared to monogastric animals, particularly CH4 where there’s the loss of potential energy in feed.
Phase 1 of rumen development Non-Ruminant (birth-21 days)
the abomasum is 60% of the total stomach, the rumen is underdeveloped and non-functional, rumen development is stimulated by dry feed intake.
Phase 2 of rumen development (22-56-84 days)
Dry feed intake, especially grain (starter) to stimulate the growth of the rumen microorganisms which produce VFA’s that stimulate the growth of rumen tissue.
Phase 3 of rumen development (more than 84 days of age)
at this stage, the calf is considered a ruminant
Omasum and its functions
A spherical organ filled with muscular laminae which are studded with papillae, its located to the right of the reticulum and rumen, known as “many piles”, has a capacity of ~10L, and moves particles from the reticulum to the abomasum, absorbs water (this is where most of the absorption takes place), reduces particle size, and continues to grind anything that wasn’t ground in the rumen.
Abomasum
known as the true stomach, essentially the same as the monogastric stomach, the first glandular portion of the ruminant GIT, digests feed fractions not fermented in the rumen, digests bacterial cell proteins produced in the rumen, uses hydrochloric acid and enzymes to digest feed, and nutrients (proteins)
Small intestine
has three segments the duodenum, the jejunum, and the Ileum
Duodenum
receives secretions from the Brunner’s gland (alkaline), Pancreas (majority of digestive juices with hormone secretion), and the liver ( bile stored in the gallbladder)
Jejunum
The active site of nutrient absorption, amino acids, sugar molecules, fatty acids, and glycerol
Ileum
The active site of nutrient absorption
What gland do horses not have?
Gallbladder, they have and use their very large cecum.
Why can absorption happen in the small intestine?
The villi and microvilli on their lining
what are the enzymes and their substrate from the small intestine?
Peptidase-peptides, lactase-lactose, sucrase (monogastric)-sucrose, Maltase-maltose, chymotrypsin-protein, trypsin-protein, lipase-triglycerides(lipids), Amylase-carbohydrate starch
Liver
Bile salts (emulsify fats and activate lipase), Cholesterol (bile salts that emulsify fats and neutralize acidic chyme are stored in the gallbladder, but made in the liver)
Why are horses considered hind-gut fermenters?
They have no gallbladder, so they store bile in their extremely large cecum
Large intestine
made of 3 segments (cecum, small and large colon, and the rectum), has limited digestion with cellulose, hemicellulose, and pectinase in the cecum and colon, fermentative digestion has no enzymes so it relies on microbes that are washed out of the small intestine, absorbs water, VFA’s, vitamins, electrolytes, and minerals, but no absorption of Lipids (fatty acids) or Protein (amino acids)
Large intestine of a horse
60% of GIT, the cecum is the location of bacterial fermentation (bacterial breakdown of VFA’s (fibrous materials)), synthesis of water-soluble vitamins, and vitamin k, and proteins are considered of limited value to the horse.
What other animal has hindgut fermentation?
Rabbit
Animals that practice coprogrophy also
depend heavily on cecal fermentation
how do the horse and cow stomachs compare?
Horses have half the stomach capacity of a cow
Feed not digested in the foregut goes where?
the cecum to be fermented
how does the foreut digest?
enzymatically
Digestive tract of poultry
crop, proventriculus, gizzard/ventricous, small intestine, ceca, and large intestine, and cloaca
crop
enlargement of the esophagus, storage of feed, some fermentation may occur here, salivary amylase
proventriculus
a glandular stomach secretes gastric juices (pepsin) and hydrochloric acid
gizzard/ventricous
grinds feed, reduces particle size, strong muscular contractions
small intestine
similar to mammals, no lactase
ceca and large intestine
water reabsorption, some fiber digestion, water-soluble vitamin synthesis, only 2-4 in. in length
cloaca
passageway for products of the urinary, digestive, and reproductive tracts
the GI hormone Gastrin
causes release of digestive enzymes, originates in pyloric cells of the stomach, stimulates the production of hydrochloric acid and pepsinogen, stimulates stomach motility, released in response to stimuli (stomach distention, hypercalcemia, or presence of partially digested proteins, especially amino acids), and is inhibited by the presence of acid in the stomach (HCL) and somatostatin
The GI hormone Secretin
originates in the cells along the walls of the duodenum, the release is stimulated by the presence of chyme and acid, stimulates the release of pancreatic juice for pH buffering, and decreases the stomachs mortality and acid function
The GI hormone Cholecystokinin (CCK)
originates in the cell wall of the duodenum, releases in response to the presence of fat and protein in the duodenum, inhibits the actions of stomach acid, stimulates bile and pancreatic secretions.
GI hormone Gastric Inhibitory Peptide (GIP)
originates in the cells along the walls of the duodenum, the release is caused by the presence of fat and glucose in the duodenum, inhibits stomach acid and enzymes, decreases stomach motility, stimulates the secretion of Insulin.
Pancreatic Hormone Insulin
Secreted from the pancreas during and following a meal, secreted when blood glucose levels increase, stimulates glucose uptake by muscle and fat cells.
Pancreatic Hormone Glucagon
secreted from the pancreas between meals or during fasting, secreted when blood levels become too low, and stimulates the liver to convert glycogen to glucose, and convert amino acids, lactic acid, etc. to glucose (glucogenesis)
