Digestibility & Energy Flashcards
What are the Nutritional Management Goals?
- Maximize (Optimize) nutrient composition: Dry Matter Intake (DMI)
- Maximize (optimize) nutrient digestion: Digestibility
- Maximize (optimize) metabolism: Nutrient Utilization Within the Body
- Maximize (optimize) animal welfare: Health
- Minimize (optimize) environmental object: Global Changes
- Maximize (optimize) economical issues: Livestock Operations Profits
- Maximize (optimize) social issues: Global Food Supply
What does Dry Matter Intake (DMI) depend on?
- Animal ( Varies by PH, Rumen size, Behavior, Selection of food)
- Food (Gut fill, physical filling, food affecting PH)
- Management (how much is ate, sufficient amounts)
When it comes to DMI what are specific animal factors that affect it?
- Animal Health (Abnormality in consumption of food)
- Animal Physiology (Pregnant cow less consumption change in rumen space)
- Animal Production Levels (What is lacking in production, could be milk, egg etc)
What are some factors that affect DMI in the terms of Dietary factors?
- Diet digestibility (how easily it can be consumed and processed)
- (food) Passage rate ( how fast food is consumed and secreted)
- (food) Particle size (Big size particles stick for a longer time in rumen = lower intake)
- Energy density (food is rich or energy dense, signals to body will lower appetite)
- Fiber content ( how much time it takes because of physical filling)
- Essential nutrients (how much it needs based off food)
- Palatability (taste of diet, affecting consumption)
- Aroma ( smell of food affecting consumption)
What are some factors affecting DMI management factors wise?
- Diet availability ( What can be given to them for food)
- Feeding frequency ( amount fed at a time)
- Environmental conditions ( temperature, wind, light)
What can digestibility be referred to as? describe how? What does it affect?
- Changes which food undergoes within the digestive tract to prepare it for absorption
- It affects how much of the nutrient consumed actually reaches animal tissues.
When it comes to digestibility how is it digested and what is it referred to as?
A certain fraction of each nutrient consumed is digested and it is referred to as digestibility coefficient.
What is the Digestibility coefficient?
The fraction of the consumed feed that is not excreted in the feces.
What is feces comprised of?
Undigested nutrients of the diet and contain endogenous nutrients.
What is Apparent Digestibility ?
It is a measurement that is easily obtained but does not account for endogenous secretions, it assumes all nutrients in feces are from food.
What is True Digestibility?
A digestibility that accounts for endogenous secretions, digestive enzymes, and pancreatic secretions.
What is the difference between apparent digestibility and true digestibility?
True digestibility accounts for endogenous secretions and is more accurate than Apparent, and it normally higher than Apparent. Apparent digestibility is an underestimate of true digestibility.
- As dietary CP increases…….
2. As Amino acids increase…..
- Endogenous CP stays relatively constant
2. endogenous digestion decreases
What factors affect digestibility ?
- Nutrient composition: (Protein, fiber, degree of lignification in fiber, lipids)
- Diet composition (ingredient composition, “associative effects”)
- Food processing: (grinding, heat, moisture, chemical)
- Dry matter intake (DMI)
- Passage rate ( particle size and particle density)
- Animal Factors (influences on DMI and therefore passage rate)
What exactly is “associative effects”?
How one feed can affect the digestibility of the other
What do you need to calculate apparent digestibility ?
- Amount of nutrient consumed
2. Amount of nutrient excreted
What do you need to calculate apparent digestibility ?
- Amount of nutrient consumed
2. Amount of nutrient excreted
What is the formula for Apparent Digestibility?
CD= (intake-excreted)/intake X100
What is the formula for true digestibility?
CD= (intake-excreted + endogenous)/ intake X 100
What is the formula for DOM (Digestible Organic Matter) = _______________________
DOM = digestible CP + digestible CF + digestible NFE + digestible EE
What is the formula for TDN (Total digestible nutrients)= ______________________
TDN= digestible CP + digestible CF + digestible NFE + (digestible EE * 2.25)
What are DOM and TDN used for in terms of?
Used in energy content of the feed
What are two methods for determining digestibility ?
- Total collection (collect everything that comes out)
2. Marker methodology (measuring quality in feed, like fiber seeing what goes in and out)
What does the total collection method require?
Total feed intake, total fecal output, and nutrient composition of the diet and feces.