UCM Animal Nutrition Quiz 1

diet

a specific mixture of feedstuffs used to supply nutrients to an animal

ration

The daily allocation of the diet that has been formulated for the animal

Monogastric

an animal with a monogastric GI tract has a stomach with one compartment

ex) swine, poultry, horses (enlarged cecum = hindgut fermenter), dogs, cats

ruminant

an animal with a ruminant GI track, has a stomach with four compartments

ex) cattle, sheep, goats

plant products consumed by animals

• seeds (grain)

  • high energy density due to highly digestible carbs and lipids

• leaves and stems

  • low energy density due to lowly digestible carbs and lack of lipids

farm animal diets are formulated primarily on the amount of ….

energy and protein required by the animal

digestion

the process by which feedstuffs are broken down into microscopic nutrient molecules

digestion via mechanical action

breakdown of feedstuffs by mastication and gastrointestinal muscular contractions

digestion via chemical action

breakdown of feedstuffs by acids in the gastrointestinal tract

digestion via enzymatic action

breakdown of feedstuff by enzymes in the gastrointestinal tract

absorption

process by which nutrients are absorbed from the GI tract through villi along the wall of the small intestines and into the bloodstream of the body

three classes of nutrients that provide energy to the animal

• carbohydrates

• lipids

• proteins

three nutrient classes that do not provide energy to the animal

• water

• vitamins

• minerals

enzymes

special proteins that catalyze reactions in the body

growth and production

condition is which animal is producing muscle tissue, milk, eggs, offspring to power

maintenance

condition in which the animal is maintaining, neither gaining or losing body condition

why is the animal’s stage of production so important?

• young animal require high levels of energy and protein in the diet to grow

• mature animals require low levels of energy and protein in the diet because they are no longer growing

what is the overall goal of an animal nutrition feeding program?

to feed a balanced diet in a ration containing feedstuffs that meet the daily nutrient requirements of the animal, which is based on the stage of production for that animal

hindgut fermenter VS monogastrics

hindgut fermenter has an enlarged cecum (horse)

why can ruminants and hindgut fermenters thrive on forages whereas monogastrics can not?

forages can only be digested by microbes, hangout fermenters and ruminants have microbial digestion

cellulase

enzyme produced by microbes to break down forages

where does microbial digestion occur in ruminants?

rumen and cecum

where does microbial digestion occur in hindgut fermenters?

cecum

order the GI tracts from most forage consumed and digested to least

1. ruminants - 44%

2. hindgut fermenter - 39%

3. monogastics = 22%

prehension of monogastics

bring food to the mouth, tongue is used

mastication of the monogastrics

means to chew, top and bottom incisors and molars

feed bolus

a soft mass of masticated feed, saliva produced in the salivary glands moistens and lubricates the feed, swallowing this is called deglution

what type of digestion occurs in the mouth?

mechanical and enzymatic digestion

amylase

enzyme present in the saliva to begin starch digestion

peristalsis

the contraction of the smooth muscles in the esophagus to move the feed bolus

sphincter

muscular structure that constricts to restrict the movement of body fluids in the body

ex) the sphincter at the entrance to the stomach keeps hydrochloric acid from refluxing into the esophagus but relaxes to allow the feed bolus to enter the stomach

what kind of digestion occurs in the stomach?

• chemical : hydrochloric acid

• enzymatic : pepsin

• mechanical : muscular contraction

NOT the major site of digestion and NO absorption occurs

pepsin

enzyme secreted into the stomach to digest protein

what keeps the stomach from digesting itself?

to avoid being digested by hydrochloric acid and pepsin, mucous is produced by special cells lining the inside of the stomach coating the stomach in protection

chyme

partially-digested feed

food bolus → chyme (after it passes out of the stomach)

order the three sections of the small intestine of monogastrics

1. duodenum, beginning section, connects to the stomach, MAJOR SITE OF DIGESTION

2. jejunum, middle section

3. ileum, end section, connects to the large intestine

what makes the duodenum the major site of digestion in monogastrics?

because the duodenum receives secretions from the gall bladder of the liver and the pancreas

job of gall bladder secretions

• bile is stored in the gall bladder from the liver

• this bile is then secreted when chyme is released from the stomach to help digest fat

• the process of bile preparing the lipids for digestion is a process called emulsification

* this is all happening in the duodenum of the small intestine *

job of pancreas secretions

• secretes buffers to increase the pH of the chyme to avoid damage to the epithelial cells that line the duodenum

  • pH is originally low after coming out of the hydrochloric acid from the stomach

• secretes enzymes to aid in digestion

  • protease = proteins

  • amylase = starch

  • lipase = lipids

* this is all happening in the duodenum of the small intestine *

what causes the secretion of buffers and enzymes from the pancreas?

two hormones are released in response to nutrients in the chyme and the low pH

1. secretin = causes release of buffers fro pancreas to raise the pH

2. cholecystokinin = causes release of enzymes and bile

job of the jejunum and ileum

MAJOR SITES OF ABSORPTION because of the villi that line the inside and increase the surface area of the small intestine

what happens if the villi of the jejunum and ileum regions of the small intestine are destroyed?

• diarrhea !

• absence of villi means the nutrients in the chyme are not being absorbed and instead the chyme passes straight through the small intestine

where is the cecum loacted in monogastrics?

between the small intestine and the large intestine

• not a major site of microbial digestion in monogastric (swine, poultry)

• instead some microbial digestion occurs in the colon

job of the large intestine in monogastrics

water absorption

job of the rectum

temporary storage of feces

four compartments of the ruminant stomach

1. rumen

2. reticulum

   • “reticulorumen”

3. omasum

4. abomasum

ruminant teeth

• bottom incisors with hard “dental pad” on top

• molars on top and bottom

bicarbonate

chemical buffer produced in saliva that helps maintain the correct pH in the rumen

• microbes needs a pH of 6-6.5 for microbial digestion

job of the esophagus in ruminants

transport the feed bolus from the mouth to the retculorumen

what is rumination?

• the process that ruminants use to get more nutrients from the food

• microbial digestion

• especially important to digest forages

reticulorumen

• consists of both the reticulum and rumen

  • rumen is lined with finger-like projections called papillae

  • reticulum is lined with ridges that form honeycomb pattern

rumen

• primary location of microbes and site of microbial digestion

• largest compartments of the stomach

  • mature bovine can hold 40-50 gallons of fluid

why is microbial digestion so effective in the rumen?

• the rumen is the site of a mutualistic symbiotic relationship (both organisms benefit)

forages are consumed but cellulose can not digest → microbes in the rumen consume the cellulose (this benefits the microbes) and produce volatile fatty acids → the volatile fatty acids are absorbed and used as energy, microbes can be digested and used as a protein source (this benefits the ruminant)