Feed Inputs to Animals
Bob von Bernuth
Considerations in a Ration/Diet
EnergyProteins & Amino AcidsMineralsVitaminsNon-nutritative additives
Energy
Energy is produced when organic molecules undergo oxidation.
C6H12O6 + 6 O2 => 6 CO2 + 6 H2O + energy
Proteins and Amino Acids
Proteins are amino acidsThere are limiting amino acids Lysine Methionine A lot of others! They should be balanced
Amino acids are the main source of N Limiting amino acids results in reducing N
excretion.
MineralsAnimals generally have a dietary requirement for
Calcium Chlorine Copper Iodine Iron Magnesium Manganese
PhosphorusPotassiumSeleniumSodiumSulfurZinc
Importance of Phosphorus
• One of the most important minerals required by livestock and poultry.
• Complexes with calcium to give rigidity to bones.
• An integral part of many organic compounds – plays important roles in energy and protein metabolism.
• Almost every biochemical reaction that occurs in muscle, blood and other soft tissues involves phosphorus.
• Affects protein synthesis, lean deposition in growing animals.
Phosphorus Requirements • Best source of unbiased information on
requirements is the nutrient requirement publications of the National Research Council (NRC).
• NRC is part of the National Academy of Sciences – a private organization established 140 years ago by President Abraham Lincoln to advise the nation on issues of science and technology.
• The Committee on Animal Nutrition of the NRC has established guidelines for feeding animals for past 75 years.
Swine versus Dairy
Swine are a monogastricDairy cattle are ruminants Ruminants have a rumen (large
stomach) Rumen contains bacteria which
produce phytase enzyme—breaks down phytate feedstuffs
Nonruminants don’t
Swine Considerations
Since they don’t have phytase—we have to overfeed P in order to ensure adequate available P. Or—we can add phytase—it works in swine, it just isn’t produced there (it also works for poultry)Or—we can use low phytate corn
Phosphorus
Essential for skeletal system developmentGenerally low availability Feedstuffs—60-75% is phytate (not
available) Corn grain—14% Soybean meal—23-30%
What happens to the rest?
Nitrogen and Phosphorus in Animal Manures
N P
(% of DM)
Manure from: Swine 4.71 2.97 Poultry 5.13 1.62 Beef 3.96 1.07 Dairy 3.75 0.79 Sheep 3.89 0.56
Sweeten (1992).
Swine and Poultry Manure High in Phosphorus - Why? • Diets (especially swine diets) generally
tend to be oversupplemented with phosphorus.
• Grains, oilseed meals in swine and poultry diets are high in phytate phosphorus.
• Pigs and poultry are unable to degrade phytase and utilize the phosphorus - no phytase in their digestive tract.
• As a result, most of dietary phosphorus from the natural ingredients is excreted in the feces.
Phytic Acid – The Culprit
PO
-
- O
O
O
PO -
-OO
OP
O-
- O
O O
PO
--O
OO
PO-
-O
O
OP
O-
-OO
O
Phytate Phosphorus
PO
-
- O
O
O
PO -
-OO
OP
O-
- O
O O
PO
--O
OO
PO-
-O
O
OP
O-
-OO
O
Zn++
Ca++
Cu ++
Zn++
Mg
++
Fe++
Phytate Phosphorus Content of Cereal Grains, Byproducts, and Oilseed Meals
Phytate Phosphorus % of total P % of total P Barley 56 Wheat bran 70Oats 56 Wheat middlings 74Corn 66Wheat 67 Soybean meal 61Grain sorghum 68 Cottonseed meal 70
Sesame meal 81
Nelson et al. (1968).
Nutritional Strategies to Reduce Phosphorus in Swine Manure • Feed diets that are not excessive in
phosphorus.
• Formulate diets on an “available phosphorus” basis.
• Use feedstuffs that are low in phytate or that have endogenous phytase.• Wheat, wheat byproducts, triticale,
barley.
• Reduce dietary phosphorus and supplement with phytase.
• Use low-phytate cereals and oilseed meals.
Model-Predicted P Excretion (kg) in Growing-Finishing Pig Fed Corn-Soy Diet from 20 to 120 kg
0.70
1.25
0.0
0.2
0.4
0.6
0.8
1.0
1.2
NRC (1998) + 0.2% Extra P
Kilo
gram
s of
P
79% More P Excreted
Phytase – What Does it Do? • Increases phytate digestibility - increases
bioavailability of P in cereal grains and oilseed meals.
• Reduces the amount of supplemental inorganic P needed to maximize growth and bone mineralization.
• Markedly reduces fecal P excretion.
• Increases the absorption of Ca, Mg, Zn, and other divalent cations.
• May improve the utilization of dietary protein and energy.
Low-Phytate Corn
Forms of Phosphorus in Germ of Normal and Mutant lpa1 Corn
0
0.1
0.2
0.3
0.4
0.5
Normal Mutant lpa1
P in
ger
m, %
Raboy et al. (1990)
Phytic Acid P
Inorganic P
Other Organic P
Soluble Carbohydrates in Soybean
SucroseUDP
UDP-Glu
Glucose+
Fructose
Fructose
UDP
Galactinol
Myo-Inositol
Sucrose
Raffinose
1
1 Myo-Inositol, 1P Synthase
ATP
ADP
Glu6P
2
Galactinol Synthase2
3
Raffinose Synthase3
4
Stachyose Synthase4
UDP-Gal
Myo-Inositol
PhyticAcid
PhyticAcid Galactinol
Myo-Inositol
Stachyose
Dairy Considerations
A dairy cow has phytase. Perhaps because of the large amount of feed she eats (50-60 lb/day) some phytase might help.However, we tend to overfeed P.
Why Do We Overfeed P?
Safety margin Not neededIncreased milk yield Doesn’t workHypophasphatemia Doesn’t helpImproves reproduction Data ???P in feed unknown No excuse
You Get Back What You Put In!
P has no gaseous phase It can’t escape to the air If you fed it, it’s in the animal, the
milk or the excretion. If you manure sample doesn’t show it,
you better look for it.
Dairy Phosphorus Balance
Total Intake
90
Unavailable
9Potentially Available
81
Milk
29
Truly Absorbed
63
189
34
34 = 61+ +
Nutrients retained by animals(Elemental)
Animal N P K
Beef 0.016 0.007 0.002
Dairy 0.012 0.007 0.002
Pork 0.023 0.007 0.002
Layers 0.022 0.006 0.002
Broilers 0.026 0.006 0.002
Turkeys 0.021 0.006 0.002