Applied Nutrition: Ruminant Feedstuff

What organic matter is included in the diet

Crude protein

Ether extract

Carbohydrates

What inorganic matter is included in the diet

Acid soluble ash (minerals)

Acid insoluble ash (silica)

Legumes have a high _____ concentration providing a high crude protein content.

nitrogen

______ is a cell wall component that is digestible by fermentation

Hemicellulose

Hemicellulose and lignin have a ______ relationship

inverse

What is Neutral Detergent Fiber (NDF)

represents the total cell wall components of the plant, including hemicellulose, cellulose, and lignin

Importance of NDF

It is a measure of fiber bulk and reflects forage intake potential

Role of NDF in digestion:

The more NDF a feed contains, the more it limits intake due to its slower digestion

What is Acid Detergent Fiber (ADF)

primarily consists of cellulose and lignin, which are less digestible portions of the plant cell wall

What makes ADF important

ADF is an indicator of forage digestibility

What is the role of feed quality of ADF:

lower ADF values generally indicate higher energy levels in forage, making it an important metric in evaluating feed quality for ruminants

What is hemicellulose

A complex carbohydrate that is easily broken down by microbes in the rumen

Hemicelluloses relation to NDF and ADF:

NDF-ADF= hemicellulose

Digestibility of hemicellulose:

provides less energy than simple sugars or starches but is a valuable energy source in high-fiber diets in ruminants

What is a cellulose

a carbohydrate polymer that provides structural integrity to plant cells

Digestibility of cellulose:

digestible by ruminant microbes but slower to break down

The digestibility _____ with the amount of lignin bound to it

decreases

What is lignin

an indigestible, complex polymer that binds to cellulose and hemicellulose

provides rigidity and structural support to the plant

As a plant matures, the content of lignin _____

increases

A higher lignin content generally correlates with _____ forage quality

lower

Role of lignin in fiber composition:

lignin is a major factor limiting the digestibility of fiber in plants

What is In-Vitro Gas Production (IVGP)

a laboratory method to evaluate feedstuff fermentation by rumen microbes

measures the volume of gas produced when feed samples are incubated with rumen fluid in a controlled environment.

What makes IVGP important?

reflects the fermentable portion of the feed and estimate the digestibility, fermentation kinetics, and energy availability of feed ingredients

IVGP role in feed evaluation

used to predict digestibility and energy values of feed, as it closely stimulates rumen conditions and microbial activity

What is Metabolizable Energy (ME):

portion of energy in feed that is available for metabolic processes after losses in feces, urine, and gases

True Dry Matter

is the dry matter content of feed after accounting for volatile compounds lost during drying (VFAs)

Importance of True DM

provides a more accurate measure of nutrient content, especially in feeds like silage, where volatile loss can affect DM values

True organic matter offers a more accurate assessment of energy-rich nutrients providing the feed's _______

energy potential

Partitioning Factor (PF)

the ratio of substrate degraded to gas produced during in vitro fermentation, indicating the efficiency of converting feed into microbial biomass versus gas

Importance of PF in feed evaluation

higher PF values means more energy is used for microbial protein, not lost in gas, which supports better animal productivity