# Shared Flashcard Set

## Details

Animal Science
Handout on Efficiency of Milk Production
11
Agriculture
11/12/2008

Term

# 1400 Pound Cow producing 14,000 pounds of milk in a 305-day lactation.

How much Grain is needed? Forage?

Definition
 To do so will require approximately 4,000 pounds of grain and 8,000 pounds of forage.
Term
 Gross Metabolizable Feedstuff Amount Fed (lb) Energy (Mcal) Energy (Mcal) Protein (lb) Grain 4,000 Forage 8,000 Milk Produced 14,000
Definition
 Gross Metabolizable Feedstuff Amount Fed (lb) Energy (Mcal) Energy (Mcal) Protein (lb) Grain 4,000 8,000 5,600 520 Forage 8,000 16,000 8,000 1,040 Milk Produced 14,000 4,760 4,760 468
Term
 Gross Energy is?  How do you measure it? What is a Mcal?
Definition
 The total amount of energy in a feedstuff. How do you measure it - light the feed on fire (actually it is burned in something called a "bomb calorimeter") and see how much energy is released (remember energy in a foodstuff is recorded in calories, the energy to raise a specific amount of water a specific temperature).  Mcal - is megacalorie or 1000 times a kcal (a kilocalorie), and it is kcals that are quoted on the back of cereal boxes and soda cans.
Term
 Digestible Energy = ? Definition?
Definition
 = Gross Energy - Fecal Energy.   That is, take the total amount of energy in the feedstuff and subtract off the energy still left in the feces.  That gives you the amount of energy the animal has available at digestion.
Term
 Metabolizable Energy = ? Definition?
Definition
 Metabolizable Energy = Digestible Energy - Urine Energy - Gas Energy (mostly methane).  So metabolizable energy is actually the amount of energy available to the animal, from a feedstuff, after subtracting all the energy lost to waste products (feces, urine and belched gas).  And don't forget - this may be an animal problem but the same concepts apply to human nutrition.
Term
 Human Metabolizable Human Digestible Energy (Mcal) Protein (lb) Grain
Definition
 Human Metabolizable Human Digestible Energy (Mcal) Protein (lb) Grain 6800 312
Term
 Estimate of gross energy in the grain that can lead to Metabolizable Energy in people= ? Protein in dairy grains is not usually ____ quality The value of protein in grains like this are _____ of the dietary value of a high quality protein like casein
Definition
 A rough estimate on the fraction of gross energy in the grain that can lead to Metabolizable Energy in people is 85% (i.e., 6800 = .85*8000).  As for the protein, the protein in dairy grains is not usually of high quality (remember, cattle are ruminants and do not need to worry about protein quality, but humans do).  Typically, the value of protein in grains like this are 60% of the dietary value of a high quality protein like casein (milk protein).  Put another way, you need to eat 1.6667 pounds of this grain protein to get the same nutritional value (often called biological value) as 1 pound of casein.  So, 312 = .6*520.
Term
 Gross Efficiency Energy in Milk/Energy in Total Feed = Protein in Milk/ Protein in Total Feed =
Definition
 Energy in Milk/Energy in Total Feed = 4760/24000 = .1983 (19.8%)  Protein in Milk/Protein in Total Feed = 468/1560 = .300 (30%)
Term
 Human Efficiency Human ME in Milk/Human ME in Grain =Human Protein in Milk/Human Protein in Grain =
Definition
 Human ME in Milk/Human ME in Grain = 4760/6800 = .70 (70%)Human Protein in Milk/Human Protein in Grain = 468/520 = .90 (90%)
Term
 Protein Efficiency on adjusted for Human Biological Value
Definition
 Human Value of Protein in Milk/Human Value of Protein in Grain = 468/312 = 1.5 (150%)
Term
 In other words, putting grains into a ruminant can actually ADD nutritional value for humans.  Of course, you can increase the efficiency to infinite by using a Total Roughage Diet.  For example, in New Zealand where no grains are fed to dairy cows, you can have a cow produce 12,000 pounds of milk (which is 4080 Mcals of energy and 400 pounds of protein) on 12,000 pounds of forage, a feeding system with NO human edible components.
Definition
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