Animal Nutrition Final

What is the nutritional-relevant portion of the plant cell wall called?

Neutral Detergent Fiber (NDF)

What different molecules make up the fiber portion of the plant?

Peptin, hemicellulose, cellulose, and lignin

What is the digestibility of peptin?

Most digestible

What is the digestibility of hemicellulose?

Highly digestible

What is the digestibility of cellulose?

Moderately digestible

What is the digestibility of lignin?

Indigestible

What are the 4 different polyphenolic compounds that make up lignin?

S-lignin, G-lignin, ferulic acid, H-lignin.H

How do the compounds that make up lignin compare in inhibition of fiber digestibility?

S-lignin is more inhibitory than g-lignin. Ferulic acid is less inhibitory than both, while H-lignin has variable effects.

How do forage species influence the concentration of lignin within a plant?

Legumes generally have more lignin than grasses.

How do forage growing conditions influence the concentration of lignin within a plant?

Warm-season forages synthesize more lignin than cold-season forages due to increased growth rates and environmental stress.

How does planting density influence the concentration of lignin within a plant?

Greater planting density typically results in reduced cell wall thickness.

How do forage genetics influence the concentration of lignin within a plant?

Brown Midrib (BMR) mutation reduces lignin

How does forage maturity influence the concentration of lignin within a plant?

As forage matures, lignin concentration generally increases, leading to reduced digestibility.

How does particle size influence fiber digestibility?

If particles are too small, they’ll pass through before optimal digestion.

How does ruminal pH influence fiber digestibility?

Bacteria that ferment fiber do so most effectively at a high ruminal pH

How does dietary fat concentration influence fiber digestibility?

Saturated fats generally have no impact on fiber digestion while unsaturated fats are highly toxic to fibrolytic bacteria.

How does dietary protein concentration influence fiber digestibility?

Most fibrolytic bacteria require free ammonia as a N source to replicate and produce the enzymes required to ferment fiber.

How do legumes fix atmospheric nitrogen?

Legumes fix atmospheric nitrogen through a symbiotic relationship with nitrogen-fixing bacteria, primarily Rhizobium, which inhabit their root nodules and convert nitrogen gas into ammonia for plant use.

Name at least 5 common species of grass used in pastures or for hay for livestock.

Timothy grass, orchardgrass, smooth bromegrass, kentucky bluegrass, reed canary grass, tall fescue, alfalfa, redtop grass

What is a cover crop?

A cover crop is a non-cash crop grown in between two cash crops.

Name at least 5 reasons why cash crops are used

Erosion control, soil health, nitrogen uptake, water infiltration, soil organic matter, nitrogen production, mineral movement, microbial diversity

Name at least 7 plants that are commonly used as cover crops

Red clover, white clover, crimson clover, kale, mustard, cowpea, turnips, radishes, forage pea, grain pea

Name 8 reasons why we may choose to process feeds at a feed mill

Increase palatability, increase surface area for digestion, remove anti-nutritional compounds, reduce bacterial load, prevent spoilage, detoxify poisonous compounds, reduce waste, and expose digestible plant compounds.

Name the 7 items that are required to be included on feed labels according to AAFCO

Feed ingredients, Guaranteed Nutrient Analysis, any active drug ingredients, instructions for use, how to mix or feed, when to feed, and any precautions/warnings.

Which regulatory body determines labeling of livestock feed? Pet food?

AAFCO for livestock, and FDA for pet food

What are the advantages of hammer milling?

Can be used on a wide variety of feedstuffs, lower initial cost, minimal maintenance, relatively easy to use, works with fibrous feeds, and can do multiple ingredients at the same time

What are the disadvantages of hammer milling?

High horsepower/energy requirement, noisy, dusty, inconsistent particle size

What are the advantages of roller milling?

Uniform particle size, more energy efficient, less dusty, less noisy

What are the disadvantages of roller milling?

High maintenance req, only for grains, hard to change particle size, greater initial cost

Why is steam added to feeds during steam flaking and steam rolling?

Steam is added to soften the hull of the grain and break down the granular structure of corn grain

Why does gelatinization of starch particles within a grain improve digestibility of that grain?

Gelatinization breaks down the intramolecular bonds of starch molecules which makes it more dissolvable in water and easier to digest

What is the difference between steam flaking and steam rolling?

Steam flaking exposes the grain to steam longer than steam flaking up to 3.5 times longer

What does a Ro-Tap shaker measure?

Determine the particle size of a processed grain

What is the difference between the process of solvent extraction and expeller extraction?

Solvent extraction uses an organic solvent (typically hexane) to remove oil from oilseeds after crushing. Expeller extraction uses a mechanical press to squeeze oil out from oilseeds after crushing.

How does the ways of processing affect nutrient composition?

Expeller extraction is typically higher in fat and lower in crude protein.

Which reaction occurs when a feed stuff is overheated? What is the biochemical change that occurs? What is the symptom of nutrient degradability?

The Maillard reaction can cause decreased protein quality

Name 7 advantages of pelleting feed

Decrease dustiness, sorting, and storage space needed
Increase palatability, use of fibrous feeds
Partial gelatinization of starch, easy delivery

Name 5 disadvantages of pelleting feed

Cost is 10-15$ per ton, pellet quality may be poor, improper pelleting leads to spoilage, requires finer grinding, difficult to pellet high fat feeds

Name 3 major types of wet feed processing

Steam rolling, steam flaking, ensiling

Which feed processing method applies heat and pressure to a grain using a tapered screw to add air to the grain and eventually create a ribbon-like product that breaks into flakes?

Extruding

Name 6 reasons why land would be used for grazing as opposed to crop production

Economical, rugged terrain, poor land fertility, limited water distribution, wildlife considerations, water runoff concerns, diverse vegetation

How does the nutrient composition of pastures change across the growing season?

Depending on temperature, humidity, and moisture the growth and digestibility will be influenced

What is the difference between intensive and extensive grazing?

Intensive grazing is tightly managed grazing where the number of animals, the pasture species, and the time on pasture are intentionally chosen to maximize use and productivity. Whereas extensive grazing is allowing animals to graze on natural vegetation.

Deferment

The delay of grazing in a pasture until the seed maturity of the key forage species is reached.

Rest

The nonuse of the pasture for one year

Rotation

The movement of livestock from one pasture to another on a scheduled basis

Name 6 common nutritional diseases associated with grazing and give 1 symptom of each

Bloat - swollen left side

Grass tetany - death

Cyanogenic glycosides - rapid labored breathing

Estrogenic flavonoids - reproductive issues

Coumarin - excessive bleeding

Nitrate toxicity - ataxia

Why is rotational grazing done?

To have other pastures growing while one is being grazed

Name 4 different grazing strategies that can be used to maintain pasture quality

Deferred rotation, rest rotation, patch burn grazing, intensive grazing

What is silvopasture?

The deliberate integration of trees & grazing operations on the same land

Utilization

The proportion of current year’s forage production that disappears by grazing animals

Harvest efficiency

The proportion of current year’s forage production that is consumed by grazing animals

What are anthelmintics used to control?

Parasites

What are 3 examples of anthelmintics?

Ivermectin, piperazine, dichlorvos

List the common antibiotic growth promotants used in feed

Aueromycin, terramycin, tylan, V-Max, GainPro, Mecadox

What is the VFD and why was it implemented?

The VFD said there would be no more growth promotion or preventative use of antibiotics due to concerns regarding antibiotic resistance.

Mycotoxin binders would most likely be added to feed when what is present?

Mycotoxins

Why are coccidiostats fed and what do they control?

Coccidiostats are fed to improve growth rate by reducing clinical and subclinical coccidiosis. They control the protozoa genus coccidia

Name 3 examples of coccidiostats

Amprolium, naracin, monensin

How do ionophores modify rumen fermentation?

Ionophores modify rumen fermentation by disrupting the proton motive force across cell membranes

Probiotic

Live microorganisms fed to promote healthy digestive and immune function

Prebiotic

Non-digestible fiber that serve as substrates to promote specific “healthy microbes” in the gut that will improve digestive and immune function

Give 3 examples of probiotics

Yeast, Bifidobacterium sp., Lactobacillis sp.

Give 3 examples of prebiotics

MOS, GOS, FOS, inulin

What is the difference between a buffer and an alkalizer? Why would both be used?

A buffer maintains a stable rumen pH and reduces pH fluctuations while an alkalizer increases rumen pH. They would be used to influence rumen pH based on how the animal is doing, if their rumen pH is too low an alkalizer can help fix that and if it tends to be all over the place a buffer can stabilize it.

Give an example of a buffer

Sodium bicarbonate

Give an example of an alkalizer

MagOx

Name two examples of enzymes that may be added to livestock diets. Why are they used?

Phytase and amylase. Enzymes are used to degrade compounds not digestible by the species.

How do beta-adrenergic agonists alter nutrient partitioning?

By moving energy towards muscle and away from fat which improves growth and feed efficiency.

Which hormone does MGA mimic to prevent reproductive cycling?

MGA mimics progesterone to prevent reproductive cycling

Why are estrous suppressants fed to some livestock?

To control and time breeding

Antioxidants are most commonly added to feeds that are high in which specific nutrient?

Fat

Provide 2 examples of common antioxidants added to diets

BHA, BHT

What can be added to feeds to inhibit mold growth?

Mold inhibitors

Provide examples of a common pellet binder

Molasses, clays, dried whey, wood products

Homeostasis

Maintenance of physiological equilibrium

Homeorhesis

Orchestrated or coordinated in tissue metabolism necessary to support the priorities of a physiological state

What are the major roles of insulin in metabolism?

Stimulates uptake of glucose from blood, glycogen synthesis, lipid synthesis, and protein synthesis

Why and how does insulin resistance occur when giving birth in mammals

Insulin resistance is a homeorhetic response to giving birth because of an immediate physiological drive to divert nutrients from body reserves to milk production. It results in a dramatic mobilization of fat which is important for the baby putting on weight initially.

What is the etiology for ketosis in dairy cows and sheep?

Ketosis in cows is caused by insufficient energy and in sheep is caused by fetuses needing more glucose than the mama has.

What is etiology of fatty liver in dairy cows and sheep?

Fatty liver in cows and sheep is caused by a negative energy balance (right before lactation in cows specifically)

How does glucagon alter metabolism?

Glucagon alters metabolism by doing the opposite of insulin such as suppressing glucose, ketones, and fatty acids. And by increasing amino acids, propionate, and butyrate.

How do glucocorticoids affect metabolism? What’s 1?

Glucocorticoids affect metabolism by decreasing glucose uptake by muscle and adipose tissues and increasing glucose synthesis in liver and muscle protein breakdown. Cortisol is a major glucocorticoid.

What is another name for somatotropin and how does it affect metabolism?

Somatotropin is also known as growth hormone and it increases insulin like growth factor 1, bone growth, release of fat from adipose, and decreases fat synthesis in adipose.

Which hormone is responsible for increasing the secretion of IGF-1?

Somatotropin/GH

Which hormones are responsible for setting the basal metabolic rate?

Thyroid hormones

What are the two major catecholamines? What is their role in metabolism? Which feed additive is an agonist for catecholamines?

Adrenaline and noradrenaline are the two major catecholamines. They increase lipid mobilization, glucose synthesis, blood glucose, metabolic rate, and protein synthesis. RAC is a feed additive agonist for catecholamines.

Orexigenic

Increase of appetite

Anorexigenic

Loss of appetite

Hunger

Lack of food

Satiety

The feeling of fullness that inhibits eating

Satiation

The process of feeling full, followed by stopping eating

Which region of the brain integrates feed intake signals to regulate hunger and satiety?

Hypothalamus

What are the major animal/production factors that regulate feed intake? How do they each affect intake?

Bigger body, faster basal metabolic rate, faster growth, more/larger offspring, and greater milk production all increase intake.

How do heat stress and cold stress affect feed intake?

Heat and cold stress significantly decrease feed intake while increasing the calories needed

Where are insulin, glucagon, and amylin secreted?

From Islets of Langerhans

How does insulin affect feed intake?

Insulin peaks after a high-glucose meal and stimulates satiety

How does glucagon affect feed intake?

Glucagon peaks during short-term fast but also induces satiety

How does amylin affect feed intake?

Amylin is co-secreted with insulin and induces satiety

Name 3 gut peptides that REDUCE feed intake

GLP-1, peptide YY, and cholecysokinin