ANIMAL-RELATED ENVIRONMENTAL
ISSUES THAT MAY BE CONTROLLED
BY ANIMAL MANAGEMENT
•
•
•
•
•
•
Nitrogen
Phosphorus
Odors
Greenhouse gases
Sediment
Species diversity
TOOLS TO MANAGE ANIMALRELATED ENVIRONMENTAL ISSUES
• Nutritional management
• Managed grazing
CONTROLLING NITROGEN EXCRETION
BY OPTIMIZING PROTEIN METABOLISM
Monogastrics
• Increase protein digestibility
• Lower crude protein intake
• Dietary balance
– Protein:energy ratio
– Balance of essential amino acids
•
•
•
•
•
•
•
•
•
•
Phenyalanine
Valine
Tryptophan
Threonine
Isoleucine
Methionine
Histidine
Arginine
Leucine
Lysine
CONTROLLING NITROGEN EXCRETION BY
OPTIMIZING PROTEIN METABOLISM
Ruminants
Protein
Escape
NPN
Protein
Metabolizable
Protein
Degraded
NH3
A
B
S
O
R
B
E
D
Microbial
protein
Converted
to urea in
liver
Excreted
• Increase protein
digestibility
• Decrease N intake
• Decrease protein
degradability
• Diet balance
– Carbohydrate
energy
– Sulfur
– Phosphorus
MANAGING NITROGEN EXCRETION BY DAIRY COWS
100 cow herd
Crude protein, %
21.3
17.1
17.1
Soybean
meal
Soybean meal
Heat-treated
soybean meal
Milk production,
lb/day
89.8
83.1
88.9
Feed cost, $/cow
3.88
3.62
3.64
Urinary
25,487
17,914
16,366
Fecal
17,597
17,740
17,721
Total
43,085
35,654
34,087
Protein
supplement
N excretion, lb/yr
CONTROLLING PHOSPHORUS
EXCRETION BY OPTIMIZING NUTRITION
• Lower P intake
– Phase feeding
• Feed phytase to monogastrics
– 50% of the phosphorus in most feeds is bound to phytic
acid
• Feed low phytate corn and soybeans to
monogastrics
• Dietary balance
– Ca:P ratio
– Vitamin D metabolites
MANAGING PHOSPHORUS EXCRETION BY DAIRY
COWS
100 cow herd
P concentration,
%
.45
.39
.36
Milk production,
lb/cow
89.8
90.3
90.6
$/cow
3.88
3.85
3.83
118
108
102
Fecal
4,540
3,565
2,992
Total
4,658
3,673
3,094
+10
-1
-7
Excreted, lb/yr
Urinary
P balance, g/day
GREENHOUSE GASES
• Carbon dioxide
• Methane (CH4)
– 21 x the greenhouse effects of CO2
• Nitrous oxide
– 310 x the greenhouse effects of CO2
SOURCE STRENGTHS OF GHG EMISSIONS
FROM DIFFERENT BEEF AND DAIRY
OPERATIONS
U.S. Beef
cowfeedlot
CA Dairy
Wis Dairy
NZ
Grazingbased
Dairy
kg carbon dioxide equivalent/kg product
Enteric
methane
5.5
.36
.41
.60
Manure
methane
.14
.21
.03
.04
Nitrous
oxide
8.1
.37
.42
.76
Carbon
dioxide
1.8
.33
.57
.22
Total GHG
15.5
1.26
1.38
1.62
WHY IS METHANE PRODUCED?
Carbohydrates
CH4
H+
Propionate
Microbial
energy
Acetate
Other
electron
acceptors
(Unsaturated
fattu acids)
CONTROLLING METHANE PRODUCTION BY
RUMINANTS THROUGH DIET MANAGEMENT
• Increase the proportion of grain and decrease the
proportion of forage in the diet
– Must have a minimum of 50% forage in dairy diets and
10% in feedlot diets
• Grind forage
• Feed ionophores
– Monensin
– Lasalocid
– Salinomycin
• Feed unsaturated fatty acids
– Maximum 5% of diet dry matter
EFFECTS OF GRAZING ON
ENVIRONMENTAL QUALITY
• Well-managed grazing
– Optimize forage
productivity and
nutritional quality
– Maximize forage species
diversity
– Improve efficiency of
forage utilization
– Maintains forage cover on
streambanks
– Minimize soil erosion
– Minimize P loading of
streams
– Minimize soil compaction
and trailing
– Maximize manure nutrient
distribution
• Poorly managed grazing
– Reduced forage
productivity and quality
– Minimize forage species
diversity
– Weed infestation
– Loss of streambank cover
– Stream widening and loss
of aquatic habitat
– Increased soil erosion
– Increased P loading of
streams
– Increased soil compaction
– Increased cow paths
– Poor manure distribution
KEY TO SUSTAINABILITY OF GRAZING
LANDS
• Managing vegetative cover through
–
–
–
–
Feed for grazing livestock
Hold soil into place
Filter water
Recycle nutrients
EFFECTS OF FORAGE CANOPY HEIGHT ON GROUND
COVER, INFILTRATION RATE, AND EROSION RATE
AFTER TREADING AT THREE RATES ON A NEW
ZEALAND HILL COUNTRY PASTURE
100
Bare ground, %
Infiltration rate, l/sq m/hr
Sediment loss, g/sq m/hr
80
60
40
20
0
0
1
2
Canopy height, inches
3
COMPONENTS OF GOOD GRAZING MANAGEMENT
• Appropriate stocking rate
– Neither too low or high
– Flexible management to maintain forage quality
• Adjust stocking rate
• Hay harvest
• Appropriate rest periods
– Based on forage growth rate
• 15 days early summer
• 35 days in mid-summer
• Appropriate design
– Number of paddocks
• 8 – 12 for rest
• 24 – 36 for grazing efficiency
– Square paddocks
– Water in each paddock
CALCULATING THE LENGTH OF OCCUPANCY FOR
PADDOCKS
• Estimate forage yield
• Estimate total forage in 5
ac paddock
• Estimate available forage
in paddock
• Estimate forage intake by
fifty 1250 lb cow-calf pairs
• Calculate days/paddock
• Calculate total paddocks
• Calculate total acres
• 15 cm x 110 lb/ac/cm = 1650 lb/ac
• 1650 lb/ac x 10 ac = 16,500 lb
• 16,500 lb x 50% = 8250 lb
• 50 x 1250 x 3.5% BW = 2188 lb/day
• 8250 lb/pad / 2188 lb/day = 3.8 days
• 35 days rest/3.8 days + 1 = 10.2
paddocks
• 10.2 paddocks x 10 ac/pad = 100 ac
Total forage mass, lb/acre
FORAGE AVAILABILITY THROUGHOUT THE YEAR
3000
2000
1000
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Months
Cool season grass
Legumes
Warm season grass
Stockpiled gr-leg (Hay equiv.)
Corn stalks (Hay equiv.)
ARRANGEMENT OF TREATMENTS
(June, 2002)
MEASUREMENT OF SEDIMENT AND
PHOSPHORUS LOSSES
Rainfall simulations
• Frequency
– June, August, October, and
April
• Locations
– 3 in 2 slope classes within
each paddock
– 3 in each buffer strip at
paddock base
– 3 in each buffer strip 30 ft
from paddock base
• Rainfall rate
– 2.8 inches/hour
• Duration
– 1.5 hours
EFFECTS OF FORAGE TREATMENTS ON
ANNUAL SEDIMENT FLOW
(Year 1)
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EFFECTS OF FORAGE TREATMENTS ON ANNUAL
TOTAL AND SOLUBLE PHOSPHORUS FLOW
(Year 1)
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