Animal Nutrition Exam 1

Which of the following is NOT one of the conditions that defines an essential nutrient?

The nutrient must always be required in large amounts.

How do plants differ from animals in amino acid synthesis?

Plants synthesize all essential amino acids from inorganic nitrogen.

Dry Matter Conversion - A feed sample weighs 200 lb as fed and is 60% dry matter. How many pounds of dry matter (DM) does it contain?

120 lb

Which of the following best describes prehension?

The taking in of feed and water

Which nutrients provide energy for the body by being oxidized to produce ATP?

Carbohydrates, lipids, and proteins

According to the text, what is considered part of the "external environment" of an animal?

Both the soil and the interior of the gastrointestinal tract

What happens to nutrient concentration when water is removed from feed?

The concentration increases

Why is feed composition often expressed on a 100% dry matter (DM) basis instead of an as fed (AF) basis?

Because water content varies widely among feeds

Why should the nutrient concentration of feedstuffs be compared on a similar dry matter basis?

Because feedstuffs often vary in moisture content

What does metabolism refer to in animal nutrition?

The sequence of chemical processes in the animal's cells

What term is used to describe nutrients that are only essential during certain life stages?

Conditionally essential nutrients

Converting Between As Fed and Dry Matter - A diet requires 50 lb of dry matter (DM) intake per day. The feed being used is 25% dry matter. How many pounds of feed must be provided on an as fed basis?

200 lb

Which statement is TRUE regarding the relationship between as fed (AF) and dry matter (DM)?

The as fed amount is greater because it includes water

What is the purpose of converting feed nutrient concentrations to a 100% dry matter basis?

To make it easier to compare feedstuffs regardless of moisture content

If a feed sample contains 10 kg of protein, 100 kg as fed total, and 50 kg dry matter total, what is the protein concentration on a dry matter basis?

20%

What is the main purpose of digestion?

To break down feed into smaller components for absorption

On a 100% dry matter basis, how are feedstuffs classified as energy feeds or protein supplements?

Energy feeds contain less than 20% crude protein; protein supplements contain more

What is the definition of nutrition?

The sum of all processes involved in consuming feed and using components for tissue growth or replacement

Which of the following describes anabolism?

Building proteins from amino acids

Which process is an example of catabolism?

Glucose being broken down for energy

What occurs during absorption?

Small molecules move through the GI tract lining into the blood or lymph

In the classification of plant and animal tissues, which components belong to the inorganic fraction of dry matter?

Minerals

What structural feature distinguishes plant cells from animal cells?

Plant cells have carbohydrate-rich cell walls, while animal cells have lipid-protein membranes.

Nutrient Concentration (As Fed vs. Dry Matter) - A feed sample contains 8 lb protein. The total weight of the feed is 80 lb as fed, and the dry matter portion is 40 lb. What is the protein concentration on an as fed basis and on a dry matter basis?

10% AF and 20% DM

Which of the following is NOT one of the six classes of nutrients?

Fiber

According to the text, how many essential nutrients are there across animal species?

Over 40

What is the primary form of energy storage in animals versus plants?

Animals store energy as fat; plants store energy as carbohydrate.

Which animal protein supplement contains the highest crude protein content?

Dried blood meal

Why do legumes generally not require nitrogen fertilization?

They use bacteria to reduce atmospheric nitrogen to ammonia

Why are oats and barley lower in energy compared to corn?

They have higher hull and fiber content

Why are mixed pastures often advantageous?

They may eliminate the need for nitrogen fertilization and provide more consistent forage growth

Why are higher quality forages usually fed to horses rather than ruminants?

Horses digest forage less efficiently

Whole cottonseed is considered

Either an energy feed or protein supplement depending on CP content

Which statement about protein quality is correct?

A good quality protein contains amino acids in proper proportions for the animal

Which statement about fats and oils is correct?

They provide 2.25 times the energy value of carbohydrates

Which stage of plant growth is most desirable for grazing to maximize nutritional value?

Leafy vegetative stage

Which process allows bacteria to make atmospheric nitrogen usable for plants?

Reduction to ammonia

Which pasture problem is associated with foam accumulation in the rumen that prevents eructation?

Bloat

Which part of the plant is generally more nutritious?

Leaves

Which of the following is the major cereal grain used as a carbonaceous feed for animals?

Corn

Which of the following is a common legume that increases soil nitrogen content?

Clover

Which nutrients are required in the greatest amounts by plants?

Nitrogen, phosphorus, potassium

Which is an advantage of rotational grazing compared to continuous grazing?

More even feces distribution and better pasture regrowth

Which grazing method uses movable electric fences to create small paddocks?

Strip (intensive rotational) grazing

Which cotton byproduct is an important roughage source for dairy and beef cattle in the South?

Cottonseed hulls

Which amino acids are commonly added as supplemental sources in feeds?

Methionine, lysine, and threonine

What is the primary purpose of adding lime to soil?

Increase soil pH to improve nutrient availability

What is the main advantage of using pasture for animal feed?

Lower feed costs and high-quality nutrients

What is the cause of fescue toxicosis in animals grazing Kentucky 31 fescue?

A fungal endophyte in the plant producing toxic compounds

What is a major problem with continuous grazing?

Overgrazing and undergrazing in patches

What does a higher leaf:stem ratio indicate?

Higher forage quality

Urea is used as a nonprotein nitrogen supplement:

Only for ruminants, because rumen microbes can convert it to amino acids

The term crude protein (CP) is calculated by:

Multiplying nitrogen content by 6.25

The most commonly used plant protein supplement in animal feeds is:

Soybean meal

The endosperm of a cereal grain seed is primarily composed of:

Starch and protein

The FDA rule of 1997 prohibited the use of:

Most mammalian proteins in ruminant feeds

Soybean meal is most commonly used as:

A protein supplement

Nitrogenous feeds are defined as concentrates containing:

More than 20% crude protein

Nitrogenous concentrates are defined as having:

More than 20% crude protein

Nitrate toxicity occurs most often under which conditions?

Excess nitrogen fertilization and drought

Molasses is primarily added to animal diets to:

Enhance palatability and reduce dust

Energy feeds are generally defined as having:

Less than 18% crude fiber or less than 35% cell wall content

Cotton textile mill byproduct typically contains:

Mostly cellulose and about 4-9% CP

Compared at the same stage of maturity, legumes generally contain more:

Protein and calcium

Compared at the same maturity, legumes generally have:

Higher calcium and magnesium concentrations than grasses

As plants age, which of the following occurs?

Protein concentration decreases

A major challenge with coproduct feeds like distillers grains is:

Variation in nutrient content between batches

Which sequence correctly orders the layers of the GI wall from inside to outside?

Mucosa → submucosa → circular muscle → longitudinal muscle → serosa

Villi are:

Projections that increase surface area for digestion/absorption

Transit time is defined as:

Time for feed to traverse the entire GI tract

The ventriculus (gizzard) in birds mainly:

Provides muscular grinding to reduce particle size

The splanchnic vascular bed includes:

GI tract, pancreas, spleen (portal vein) and the liver in series

The small intestine maximizes surface area using:

Folds, villi, and microvilli

The rumen is lined with papillae that absorb:

Short-chain fatty acids (VFAs) and ammonia

The rumen environment is largely anaerobic, meaning:

It is without oxygen; microbes use up oxygen entering with feed

The rumen ecosystem is termed an ecosystem because it includes:

Organisms and their environment with processes maintaining constancy

The reticular groove in young ruminants:

Allows milk to bypass rumen fermentation during suckling

The proventriculus in birds:

Is analogous to the mammalian fundic region, secreting mucus, HCl, pepsinogen

The primary site of absorption is the:

Small intestine

The omasum in ruminants primarily:

Absorbs water; digesta is drier leaving it

The lumen of the GI tract is:

The interior of the GI tube through which feed travels

The large intestine mainly:

Absorbs water/electrolytes and hosts microbial fermentation

The enteric nervous system:

Locally regulates motility and secretions in response to luminal conditions

The cloaca is:

A common opening for digestive and urinary systems

The abomasum is the:

Glandular stomach analogous to the simple stomach, secreting HCl/pepsinogen

Somatostatin in the GI tract:

Decreases motility and reduces several GI hormones

Secretin is released in response to acidic digesta and:

Stimulates watery bicarbonate secretion from the pancreas

Saliva is approximately:

99% water with mucin, buffers, enzymes, and urea

Rumination is:

Controlled regurgitation to rechew feed, reducing particle size

Ruminant stomach compartments (in discussion order) include all except:

Proventriculus

Prehension refers to:

Seizing and bringing feed/water to the mouth

Pregastric fermentation occurs:

Before the glandular region; characteristic of animals with complex stomachs

Postgastric fermentation refers to microbial activity occurring mainly in the:

Cecum and/or colon

Pepsin is classified in the text as a(n):

Endopeptidase

Oxyntic (parietal) cells secrete:

HCl and intrinsic factor

Order of small intestine segments is:

Duodenum → jejunum → ileum

Most absorbed nutrients travel first to the liver via the:

Portal vein

Many enzyme names end with:

-ase

Lipids are absorbed primarily via the:

Lymphatic system (lacteals → thoracic duct)

In this text, a hormone is best described as a substance that:

Is produced in GI tissues to regulate motility/secretions