animal-related environmental issues that may be controlled by animal management nitrogen phosphorus...

ANIMAL-RELATED ENVIRONMENTAL ISSUES THAT MAY BE CONTROLLED

BY ANIMAL MANAGEMENT• Nitrogen• Phosphorus• Odors• Greenhouse gases• Sediment• Species diversity

TOOLS TO MANAGE ANIMAL-RELATED 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

• Increase protein digestibility

• Decrease N intake• Decrease protein

degradability• Diet balance

– Carbohydrate energy

– Sulfur

– Phosphorus

Protein

Protein

Degraded

Escape

NH3Microbialprotein

Convertedto urea inliver

MetabolizableProtein

ABSORBED

Excreted

NPN

CONTROLLING NITROGEN EXCRETION BY OPTIMIZING PROTEIN METABOLISM

Ruminants

MANAGING NITROGEN EXCRETION BY DAIRY COWS100 cow herd

Crude protein, % 21.3 17.1 17.1

Protein supplement

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

N excretion, lb/yr

Urinary 25,487 17,914 16,366

Fecal 17,597 17,740 17,721

Total 43,085 35,654 34,087

• 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

CONTROLLING PHOSPHORUS EXCRETION BY OPTIMIZING NUTRITION

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

Excreted, lb/yr

Urinary 118 108 102

Fecal 4,540 3,565 2,992

Total 4,658 3,673 3,094

P balance, g/day +10 -1 -7

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 cow-feedlot

CA Dairy Wis Dairy NZ Grazing-based 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

Microbialenergy Acetate

H+ hhhhhhh

CH4

Propionate 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

Canopy height, inches

0 1 2 30

20

40

60

80

100Bare ground, % Infiltration rate, l/sq m/hr Sediment loss, g/sq m/hr

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

Months

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

To

tal

fora

ge

ma

ss

, lb

/ac

re

0

1000

2000

3000

Cool season grassLegumesWarm season grassStockpiled gr-leg (Hay equiv.)Corn stalks (Hay equiv.)

FORAGE AVAILABILITY THROUGHOUT THE YEAR

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)

Grazing treatment

Se

dim

en

tati

on

, lb

/ac

.

0

10

20

30

40

50

60

70Ungrazed Hay/stockpile 2" Continuous 2" Rotational 4" Rotational

a

b

b b

b

Total P Soluble P

lb/a

c

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35Ungrazed Hay/stockpile 2" Continuous 2" Rotational 4" Rotational

a

b

bb

b

bb

a

c

c

EFFECTS OF FORAGE TREATMENTS ON ANNUAL TOTAL AND SOLUBLE PHOSPHORUS FLOW

(Year 1)