Nutrient Reduction in Manure
through Livestock Nutritional
Management
Balancing Animal Performance
and Manure Management
Manure Management
• N and P are the two nutrients of greatest
concern when dealing with manure.
• N and P can be managed and utilized as
fertilizer for crop production.
Nutrient Management
• Nitrogen
– Protein
• UIP
• DIP
• NPN
– Amino acids
• Phosphorus
– grains -- high
– forages -- low
– dicalcium phosphate
Ruminant Animals
Yearly excretion estimates of various
nutrients by 1400 lb Holstein cows
Fraction
Milk
DMI
Raw manure (feces & urine)
Total N (low NRC)
Total N (high NRC)
P (.40% P RDM)
P (.45% P RDM)
P (.60% P RDM)
K (.8% K RDM)
K (1.2% K RDM)
Similar trends Ca, Mg, Na, Cl
UIP and DIP minimums met
Total for year
21750 lbs
14462 lbs
47475 lbs
223 lbs
260 lbs
40 lbs
46 lbs
69 lbs
88 lbs
146 lbs
NRC 1989
Composition of Fresh Manure
N: 9.4 lb actual N/ton wet manure
P: 1.9 lb actual P/ton wet manure
K: 3.7 lb actual K/ton wet manure
Total solids 12.8%
• Composition will change with scraping
and loading moisture content and
volatilization of N
MWPS - 18
1,000 lb Market Animal
60 lb/day manure
.34 lb/day N
.11 lb/day P
(154 g)
(50 g)
Nitrogen Losses
•
•
•
•
100%
50 to 60%
15 to 20%
20 to 30%
Nitrogen Excreted
Volatilization
Runoff, soil
Removed
Nitrogen Losses
154 g N/d x .25 =
38.5g N/hd/d removed from pens
Predictable Equations
• P and N excretions by cows vary
– P or N intake
• Factors
– P or N intake
– Dry Matter Intake (DMI)
– Milk yield
Morse et al.
NRC 1996: Phosphorus
• Maintenance (Pm) Requirement
16 mg P/kg BW
• Retained (Pg) Phosphorus
3.9 g/100 g protein gain
NRC 1984: Phosphorus
• .028 (Wkg) + .039  protein gain (g/d)
• Maintenance Requirement Reduced
• 43% (1984
1996)
P Requirements
Animal (lbs)
Daily P requirement (gms)
150
7.7
300
11.4
900
20.9
1400 (dry)
18.2
1400 (late dry)
25.4
1400 (35 lbs milk)
46.7
1400 (70 lbs milk)
75.3
1400 (100 lbs milk)
100
Dairy NRC recommendations
• .35% P RDM is enough for optimum
performance
• Levels of .6% or higher not uncommon
1996 NRC Phosphorus Requirements
Typical Yearling (800 lb)
0.22% of diet DM
or
22.6 g/d P Intake
Typical Feedlot Diets
.30 to .35% P on diet DM
Practical Considerations
• Corn-based diets will run .25 to .35% P
• The need for supplemental P is low
Steer Performance as Influenced by P
%P
P Intake,g/d ADG, lb/d
DMI, lb/d
0.14
0.19
0.24
0.29
0.34
15.9
19.7
27.6
32.1
36.4
3.87
3.57
3.77
3.85
3.38
25.0
22.8
25.2
24.4
23.6
SE
.74
.20
.73
Feed/Gain
6.49
6.37
6.71
6.33
7.04
Erickson et al, 1998; Nebraska
Phase Feeding
• Opportunities to lower N and P intakes
during the latter stages of the finishing
period. Consequently, this will lower N
and P output
• Allows nutritionists to more effectively
optimize performance w/o overfeeding.
Yearlings (Trial 1; Nebraska 1998)
CTL
Fin 1
Fin 2
Fin 3
CP (%)
UIP (%)
P (%)
13.6
11.2
11.9
11.5
4.48
3.67
3.67
3.67
.34
.24
.24
.22
Performance : Yearlings
Item
Control
Initial Wt.
652
Final Wt.
1249
DMI
26.2
ADG
4.06
F/G
6.45
Erickson, et al; 1998
Balanced
660
1249
25.0*
4.01
6.21
SE
2.8
9.8
.2
.06
Phosphorus Balance (lbs/hd)
Item
Intake
Retention
Excreted
Manure
Soil
Runoff
Difference
Control
12.52
2.05
10.47
6.77
-1.25
1.75
3.21
Balanced
7.90
2.03
5.87
6.49
-2.99
1.49
0.89
135 d/period for both yearlings and calves treatments
Management Practices to
Improve N & P Retention
IMPLANTS?
Effect of TBA + E2 on
Nitrogen Retention of Steers
Treatment
LW (lb)
Period
(days)
CTL TBA + E2
-14
+ 7
+28
+49
+70
777
821
876
902
953
774
834
906
972
1043
N Retention (g/d)
CTL
19.3
21.6
21.0
19.6
18.5
TBA + E2
23.2
43.6*
52.1**
57.0**
36.5*
Lobley et al, 1985; Br. J. Nutr. 54:681-694.
Phosphorus Balance
Item
CTL
IMP
P Intake, g/d
Pm, g/d
Carcass Protein Gain, g/d
WB Protein Gain, g/d
Pg, g/d
P Excreted, g/d
P Calculated (.68) g/d
P Excess, g/d
26.14
6.89
114
142
5.54
20.6
18.3
7.8
27.19
6.99
207
259
10.10
17.09
25.1
2.09
Swine Management
Nitrogen
• Pigs require amino acids, not protein
• Use synthetic amino acids
% of NRC Requirements
Protein vs Amino Acid Req
200
180
160
140
120
100
80
60
40
20
0
Lys
Trp
Thr
C-SBM
C-MBM
Diets
C-PM
Synthetic Lysine
• Replace 100 lbs of SBM with 3 lbs
synthetic lysine and 97 lbs of corn
• Save $3.96/ton
– Corn @$1.70/bu & SBM @ $205/ton
• Save $1.32/pig
• Reduce N excretion by 22%
• Reduce odor from ammonia
Split-Sex Feeding
• Gilts eat less feed and put on more lean
tissue
• Feed gilts higher AA < 80 lbs
• Save $1.40/pig
• Reduce N excretion by 5%
Phase Feeding
• By feeding more diets, you decrease the
amount of time you are over-and underfeeding AA.
• By using 5 Grower-Finisher diets instead
of 2, save $1.60/pig
• Decrease N excretion by 5-8%
Genotypical Feeding
• Pig will only perform to genetic
capability.
• Increasing protein/AA levels to a
genetically average pig will NOT increase
muscle.
• Match genetics to nutrition
• Reduce N excretion & odor
• Save $$$$
Antibiotics
• Some preliminary data shows that
certain antibiotics may be nitrogen
sparing.
• Potentially less N excretion and ammonia
production
Balance on Available Amino Acids
• When using something besides a cornSBM diet
• Add less N to the diet
• Reduce N excretion and ammonia
production
Reducing Sulfur Excretion
• Amino acids
– methionine
– cysteine
• Minerals
– copper sulfate
– ferrous sulfate
Dietary Modifications
• Reduced protein from 13 to 8% and
added synthetic AA to meet requirement
• Replaced copper sulfate with copper
oxide
• Replaced ferrous sulfate with ferric
chloride
Results
• Reduced N in manure by 45%
• Reduced volatile fatty acids (VFA’s) by
61%
• Reduced sulfur compounds in air by 63%
Adding 5% Cellulose to Diet
• Reduced pH from 7.8 to 6.4
• Reduced ammonia emissions by 68%
• Reduced sulfur volatile organic
compounds by 12%
• While these may not all be practical at
the present, it does demonstrate that we
can affect nutrient excretions by how we
feed the pig.
Phosphorus (P)
• Only 30% of P in grain is available
• Rest is in phytate form and is unavailable
Add Phytases
• Phytases are enzymes that make phytate
P more available
• Reduce P excretion by 30%
• Add less dicalcium phosphate
• Economic“wash” when compare to dical
price
• Some reports of slight savings
Cost of P Excretion
• It takes 3 times more land to spread hog
manure on when you base the
recommendation on P instead of N
• Potential BIG cost in the future
Low Phytate Corn
• “Gene Jockeys” and plant breeders have
developed corn varieties with very low
levels of phytate P.
• Commercially available in a year or two
Distiller’s Dried Grains from SD & MN
• Research on DDG from SD & MN
ethanol plants shows that P is 60% more
available from their products
• Tremendous opportunity for gestating
sows and finishing pigs
• Low in lysine
Balance on Available P
• Do when using other feedstuffs than corn
and soybean meal
• Add less inorganic P (cheaper)
• Less P excretion
Improving Feed Efficiency
• Anything that improves feed efficiency
will decrease feed in the dust or the
amount of feed ending up in the manure,
thereby reducing the nutrient load in the
manure and the substrate for odor
production.
Improving Feed Efficiency
•
•
•
•
•
•
Fat additions (1% most economical)
Proper feeder adjustment
Pelleted diets
Wet/dry feeders
Growth promotants
Covers on drop-spouts
Conclusions
• Environmental issues will continue to be
important in the livestock industry.
• By utilizing certain nutrition schemes
and management tools we can
theoretically lower our inputs and
outputs of N and P.
• We all need to do our job in protecting
the environment.