Forage Crops Exam 1

3 Main objectives for Sustainable Agriculture

1. Environmental Health

2. Economic Profitably

3. Social and Economic Equity

Factors within Environmental Health to support Sustainable Ag

• Soil Health (fertility)

• Air Quality

• Plant Composition

• Water Quality (runoff, erosion)

Factors within Economic Profitability to support Sustainable Ag

• Reducing inputs (fertilization, equipment, cost)

Factors within Social & Economic Equity to support Sustainable Ag

• Public image/outside perspective

• Soil Farms

5 How to ways to Regenerative Agriculture

1. Keep soil covered

2. Maintain living root year around (irradiation,)

3. Minimize soil disturbance (CO2 problems)

4. Integrate livestock

5. Maximize crop diversity

Trying to regenerate _____ in the soil and increase organic matter (contains a carbon atom)

CARBON = organic matter

What is the main goal of Grassland Agriculture?

Managing grasslands in multiple aspects

6 Main Threats to Grassland Agriculture

1. Low water areas (droughts/wildfires)

2. Urbanization (animal overgrazing)

3. Desertification

4. Veganism (plant based foods)

5. Land use change (tillage)

6. Special interest groups (crows/wolves)

What is and what does FMV stand for?

Forage Nutritive Value:

The extent to which a forage has the potential to produce a desired animal response

Types of Nutrition Facts on a food product that = the forage value in feed

Fiber

Carbs

Protein

Sugar

etc.

What is the animal’s Forage Nutritive Value?

Where the forage has the potential to produce a desired animal response

What is the animal’s Forage Quality?

The animals response/animal’s performance--not a nutritive value

Common Measurements of Nutritive Value

DM

NDF (neutral)

ADF (acid)

CP

ADIN (acid-insoluble Nitrogen)

Digestibility

Anti-nutritive factors

What is DM and what its significance?

• Moisture removal and what’s leftover

• Lower DM=Higher moisture content

  • ex: canned dog food low DM (mostly water)

  • ex: limestone (high DM, barely any water)

What is NDF, and what was its significance

• Neutral Detergent Fiber (NDF)

• Within the cell walls/content of energy

• Cellulose, hemicellulose, lignin (how mature your plants are)

Cells Walls of NDF

Primary (exterior)

• contain pectin

Secondary (interior)

• lignin

Plasma Membrane

How does plant maturity directly affect digestibility?

Younger plants are high in protein and easily digested, while older plants accumulate more fiber and lignin, reducing digestibility.

Forage harvest timing is one of the biggest management decisions in animal nutrition.

• Young plant (high digestibility)

• Old Plant (low digestibility)

The lower the ______ , the more digestible the plant is.

The higher the fiber in a plant = the ____ the cell contents (the good stuff/protein)

Fiber

Lower

True or False: Lignin is easy to digest

False

• Lignin: essentially indigestible and “locks up” the other fibers, reducing their availability.

When dealing with cell walls, ___ fiber is better

Lower

(more fiber — more mature plant)

What exactly predicts an animals intake?

NDF predicts intake caused by bulkiness and fill-limiting fiber fraction of the diet. Higher NDF = lower intake

Lower NDF allows greater intake

• Digestibility plays a big role too

What is the most important factor affecting nutritive value?

Maturity

Why can 2 forages with the same NDF% have very different effects on intake?

• Digestibility of NDF varies. Younger plants have more digestible fiber, while mature plants have higher lignin (indigestible), reducing intake further.

• NOT ALL NDF are created equal

What are the main differences between NDF and ADF?

NDF: cell, hemi, lignin

ADF: cell, lignin (hemi is dissolved away)

• ADF is closely related to the digestibility of the forage.

• Higher ADF = lower energy availability.

• So, ADF is used to predict how much energy the animal can extract from the forage.

What is CP and what exactly is it measuring?

Measures Nitrogen in a sample
%N x 6.25 conversion of NPN to microbial protein indicator of forage maturity

Higher protein, low in fiber, good digestibility

What is ADIN and what is it used for?

Acid Detergent Insoluble Nitrogen

A portion of nitrogen (mostly from protein) that gets bound to the acid detergent fiber (ADF) fraction of a feed during heat damage or processing. (Nitrogen is trapped in indigestible fiber/lignin)(hard to digest)

Measured as a %

It reduces usable protein for the animal, even if crude protein looks high on paper.

Good vs Bad ADIN

• Normal, good-quality forage has low ADIN (little heat damage).

• High ADIN indicates heat-damaged protein (common in “brown” or “caramelized” hay/silage).

What does True Digestibility mean?

The actual amount of forage that can be broken down and

• marked as a %

“In Vitro” True Digestibility

-”in the lab method tests” not inside a live animal

Rumen has microbes that produce gas when pressure and measures how much of the forage was acutely digested

“In Situ” True Digestibility

-” in the actual place of the animal”- digestibility measured inside the animal

• Measuring forage inside the animal via a bag containing forage that is tied to a weighted chain and lowered into the rumen through a fistula (a surgically made opening).

• Actually using the “rumen”

• After a set time, the bag is pulled out, and the undigested residue is analyzed.

• “What the animal is actually getting out of the product”

How does IVTD and In Situ help test farmers?

Together, these tests help farmers and nutritionists know how much energy and nutrients animals can really get from a forage, which guides feeding decisions.

5 Factors that Affect Nutritive Value and Forage Quality

1. Maturity

2. Species (sunlight/type of plant)

3. Environmental Factors

4. Anti-Nutritional Factors

5. Harvesting and Storage Methods

#1 Forage Maturity

The most important factor

• Younger (less mature/more protein) plants are higher quality and more valuable as feed

• more mature = less digestibility (higher lignin/fiber/lower protein)

Maturity Leaf to stem Ratio

• Leaves are more digestible and higher in protein than stems.

• A higher leaf: stem ratio means better forage quality.

• As the plant matures, the ratio shifts: fewer leaves, more stem, which lowers feed quality.

Legumes have a ___ protein content

Higher because they can fixate nitrogen by taking in Nitrogen from the air and putting it into their root system, thus turning it into protein (intake nitrogen → ETC → Protein → animal intake)

Common types of Grass Species

Tall Fescue

Eastern Gamma Grass

Annual Lespedeza

Fescue-Clover Stockpile

When dealing with the environmental factors of a forage:

Higher temperatures → _____

Lower temperatures → ____

Why?

Higher temp: Lower digestibility

• Hot conditions, plants mature/grow faster and deposit more lignin. (hard to digest)

Lower temp: higher digestibility

• Cold conditions, plants grow/mature more slower and maintain soluble nutrients slowly

Temp speeds up plant life

Sunlight vs. shade.

• More sunlight → faster maturity. The plant grows quickly, but the forage becomes fibrous sooner.

• Shade → higher nutritive value, slower maturity. Shaded plants may have higher protein or digestibility, but they produce less forage mass.

• Trade-off: Farmers must balance quality (nutrient content) against quantity (forage yield).

Ultisols → _______ fertility

Inceptisols —> ______ fertility

Why is that?

Intermediate fertility

Poor fertility

Soils with greater fertility improve digestibility and overall productivity.

Examples of Anti-Nutritional Factors

harmful to livestock, chemical compounds from plants that are adapted as defense mechanisms

What organism can digest lignin and why?

Termites and other wood eating insect based on the anatomy of their digestive system and current wood diet

What do tannis do?

Bind to proteins as secondary compounds that is produced by the plant that isn’t directly needed for growth purposes

What are the 2 types of Tannis?

Condense Tannis (phenolic)

• hard to break due to 6 rings

• less toxic

• benefical

• hard to digest (not for small ruminants though)

Hydrolysable Tannins

• Glucose sugar

• one ring

• fragile

• more toxic (kidney faluire)

• very digestible (due to sugar)

Why can small ruminants eat Condensed Tannins (CT)?

Small ruminants have a higher liver content and can digest CT due to microbes in the rumen

What in the world are saponins, and what is their purpose?

Active plant constituents: produce soap-like lather in water.

Produces stable protein foams, causes bloat due to oxalic acid and mediagenic acid i.e. Alfalfa

What are Alkaloids?

Causes major central nervous system disorders

• Drugs

• Nicotine

• Caffeine

Largest class of antinutritional factors
truly toxic to animals

Why is Jimson weed so dangerous?

Contains toxic alkaloids that affect the nervous system. These compounds are tropane alkaloids:

What is an endophyte fungus?

Fungus that lives inside the plant tissue without causing disease to the plant.

• Kentucky-31),

The fungus produces toxic alkaloids that affect animals grazing on it.

What is an Ergo Valine?

Primary toxic alkaloid produced by the endophyte in tall fescue.

It causes problems in livestock (cattle, sheep, horses). Kentucky-31 tall fescue covers about 6.6 million acres in Missouri, so it’s a widespread issue.

What is ergot alkaloid toxicosis?

Ergot alkaloid toxicosis is a condition that occurs when livestock consume forages (like endophyte-infected tall fescue or grains infected with ergot fungus) that contain ergot alkaloids—toxic compounds produced by fungi.

What happens to livestock during ergot alkaloid toxicosis with hot weather?

• Animals can’t shed heat properly because alkaloids cause vasoconstriction (blood vessels don’t open to release heat).

• Signs:

  • Overheating, panting (↑ respiration rate).

  • Animals spend time standing in ponds or shade instead of grazing.

  • Reduced appetite and weight loss.

What happens to livestock during ergot alkaloid toxicosis with cold weather?

• Same vasoconstriction effect, but now blood doesn’t flow well to the extremities.

• Leads to fescue foot: tails, ears, and hooves lose circulation, tissue dies, frostbite-like damage, bleeding, and in severe cases, sloughing of hooves.