Principles of Animal Nutrition

Why is knowing the nutritional values of feed important?

All feeds are not equal, Nutrient Composition, Economics, Cost of production

What is proximate analysis?

chemical procedure, set of chemical/analytical procedures developed in Weende, Germany over 100 years ago, estimate nutrient composition

What does dry matter estimate?

H2O

How is crude protein calculated

measured using nitrogen content of sample. %N *6.25

What does ether extract measure?

lipid content

What does ash analysis measure?

minerals

What are the two main tests for carb analysis?

NDF and ADF

What is the Van Soest Method

A method used for analyzing the fiber content in animal feed, specifically measuring neutral detergent fiber (NDF) and acid detergent fiber (ADF).

What types of fibers does the Van Soest measure?

hemicellulose, cellulose, lignin

What types of fibers can be measure via NDF and ADF

NDF -Hemicellulose

ADF - Ligning and Cellulose

Define a calorie

heat required to raise the temp by of water by 1 degree celsius

What is energy derived from?

CHO - sugar, starches, fiber, Fat, Protein

What are the three methods of chemical analysis for predicted energy values?

Atwaters Physiological Fuel Values, Bomb Calorimetry, TDN (total digestible nutrients)

Larger cecum =

more fiber digestion, typically herbivores

Digestion

breakdown of large molecules to simpler, smaller chemical compounds that can be absorbed

What is the purpose of digestion?

Prepare for absorption, complete molecules are small enough to be absorbed

What are the three main methods of digestion? give examples.

Physical/ Mechanical Action: chewing (ruminenets)

Chemical Action: HCl starting protein digestion

Enzymatic Action: specific substrates

Define absorption.

set of processes that result in passage of small molecules from lumin of gut through cells

What is the role of surface area for absorption?

Increased surface area enhances the efficiency of nutrient absorption by providing more space for molecules to pass through the intestinal wall.

What are the role of folds, villi, and brush borders and how much do they increase surface area?

Folds and villi allow for more nutrient absorption in the SI the villi can catch micro nutrients.

Define passive diffusion and give an example

passage of substance from lumen into intestional cells due to concentration gradient, High [C] → Low [C], no energy is required

Define active diffusion and give an examples

absorption from lumen to intestional cells against a concentration gradient, Low [C] → High [C], required carrier protein and energy

Define facilitated diffusion and give an example

similar to active diffusion except not against [C] gradient and no energy required, High [C] → Low [C], carrier protein required but no energy

Define phagocytosis and know its role in neonates

Absorption when part of villi cell breaks off and engulfs a nutrient, no digestion required, absorb large molecules (important for antibodies after birth)

What are the 9 steps of digestion in order?

Prehension

Mastication

Salivation

Swallowing

Stomach

Small Intestine

Large Intestine

Defacation

Urination

Define prehension

seizing and conveying of food to the mouth

What are the means of prehension in different species?

Biped - upper limbs, Quadrupeds - mouth, teeth, lips, Herbivores - mouth, tongue, lips

Define Mastication

vertical movements of the jaw which crush the food particles between teeth

How does mastication vary between carnivores, omnivores, herbivores, and ruminents

Carnivore: reduce mean to be swallowed

Omnivores - limited, no avian

Herbivores - thorough need

What part of mastication is special in horses?

cannot regurgitate

Define salivation

secretion and mixing saliva with food

What are the three main salivary glans and where are they located?

Parotid - beneath ear

Submandibular - side of jaw

Sublingual - under tongue

How does the amount of saliva produced vary across species?

Herbivore most saliva, 40-150 L, Omnivores - 1500 mL, Carnivores - 200mL

What can be found in saliva?

water - 99%, mucin, electrolytes, salivary amylase

What species contain salivary amylase?

man, apes, pigs, rats, avian

What are the 7 functions of saliva

lubrication of food, solvent (dissolve into solution), cleans oral cavity, washes dental cavity, buffer, nitrogen recycling in ruminents, phosphorus in ruminents

Define deglutition

reflex of passing anything from the mouth through the esophagus to the stomach

How does the horse differ from other species?

cannot regurgitate the food