Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
30 Cards in this Set
- Front
- Back
|
Acronyms: NEm NEL |
DE: Digestible Energy GE: Gross Energy ME: Metabolizable Energy NE: Net Energy NEG: net energy for gain NEL: net energy for lactation |
|
|
Energy
(learning objective) |
- the potential to do work - is not a nutrient, but the result of nutrient metabolism |
|
|
How is energy expressed? |
as Mjoules (Kjoules) or Mcal (Kcal)
1 Mcal = 4.184 MJ |
|
|
1 calorie is... |
the amount of energy as heat required to raise the temp of 1 g of water from 16.5 to 17.5 degrees celcius |
|
|
Energy Partitioning flow chart
(learning objective) |
|
|
|
Gross Energy |
- the heat of combustion. The energy released when an organic substance is oxidized to CO2 and H2O. - doesn't give indication of energy availability to animal - dependent on the proportion of fat, CHO, and protein in the feed |
|
|
Normal gross energy values for CHO, protein, and fat |
CHO = 4.2 kcal/g
Protein = 5.6 kcal/g
Fat = 9.4 kcal/g |
|
|
How to calculate digestible energy |
DE = gross energy intake - gross energy of feces |
|
|
How does increasing feed intake affect DE? |
Digestible energy decreases with increasing feed intake due to faster rate of passage through the GI tract |
|
|
One problem with digestible energy values is that |
it does not account for losses of energy associated with digestion and metabolism; it over-estimates the value of high fibre feeds (hay and straw) relative to low fibre feeds (grains) |
|
|
TDN |
total digestible nutrients
- an outdated method of expressing the energy value of a feed (but is still used) |
|
|
formula for estimating TDN |
% TDN = DCP + DCF + DNFE + (DEE*2.25)
DCP: digestible crude protein DCF: digestible crude fibre DNFE: digestible nitrogen-free extract DEE: digestible ether extract |
|
|
1 kg TDN = |
4.4 Mcal DE |
|
|
Metabolizable energy formula |
ME = DE - (energy in urine + energy lost as gas) |
|
|
Gas losses of swine, small animals, and ruminants |
swine and small animals have minimal gas losses ME is 94-98% of DE
ruminants have higher gas losses and has more variability ME is ~80% of DE methane production causes a 7% loss of GE |
|
|
Why is ME measured more easily than DE in poultry? |
because their feces and urine are voided together |
|
|
Factors that affect ME values (3) |
Type of Digestion (ruminant vs. monogastric)
End use of amino acids (protein synthesis vs. energy source)
Feed Intake: inverse relationship with energy value |
|
|
Net Energy formula |
NE = ME - heat increment of feeding
heat increment of feeding: energy costs of digestive and metabolic processes |
|
|
What is Net Energy? |
the energy available to the animal for maintenance and productive purposes |
|
|
NEm
|
NEM = NE for maintenance
- is used to perform work within the body and will leave the animal as heat |
|
|
NEG and NEL |
NEG = NE for gain NEL = NE for lactation
- used for growth and fattening and for milk, egg, or wool production - together they are referred to as the animal's energy retention (retained energy) |
|
|
The energy systems used for dairy, beef, swine, poultry, and companion animals |
Dairy: NE system. Mature cows, only NEL used. Growing cows: NEL for maintenance and lactation, NEG for growth
Beef: ME or NE system, maybe TDN Swine: ME or NE system Poultry: ME system Companion Animals: ME system |
|
|
Energy Requirements and its affecting factors |
Factors the influence an animal's energy requirement: BW, growth, gestation, lactation, egg or wool production, exercise, environment |
|
|
ME values for CHO, Protein, and Fat in dogs and cats (know these numbers!) |
CHO = 3.5 kcal/g Protein = 3.5 kcal/g Fat = 8.5 kcal/g
- determined using GE values, digestibility coefficients, and urinary losses. Ex. CHO, GE of 4.2 with a digestibility coefficient of 85%. 4.2 x .85 = 3.5 |
|
|
First step for calculating ME content of Dog Food
(know how to do this and the next few flashcards!) |
need to find the NFE. use the food label on the dog food bag and use an assumed value for ash, as it's not listed.
NFE = 100 - %H2O - %CP - %fat - %CF - %ash |
|
|
Once you get your NFE, you use that value as the CHO % in diet. Now that you have your CHO, protein, and fat % in the diet, now what? |
Use your constant ME values (3.5, 3.5, 8.5) from 2 slides back. Then, calculate the Kcal/100g of dog food for each nutrient. Ex. Protein is 26% of diet. Multiply that by your ME. 26 x 3.5 = 91.0 Kcal/100 g of dog food |
|
|
Once you get all your nutrients converted to Kcal/100g of dog food, then what? |
Add all the values together to get your total calories. Then convert the final answer to kcal/kg Ex. total calories = 348.0 kcal/100 g 348 kcal/100g x 1000g/1kg = 3480 kcal/kg |
|
|
Final chart for ME content (for perspective) |
|
|
|
Why do we care about energy? |
Energy requirements determines feed intake. Feed intake determines the concentration of nutrients required in the diet |
|
|
Too complicated to put in flashcards, but be able to calculate CP intake and Ca intake in terms of g/day. (this was the fiasco happening on the board earlier) |
blah |
