Principles of Managed Grazing

Karen HoffmanResource Conservationist – Animal Science

USDA-NRCSNorwich, NY, USA

Natural Resources Conservation Service

Managed Pasture Systems

• Small paddocks

• Short duration

• Rest interval

• 6-8” forage height

The goal of a pasture plan is to ensure the forage supply is kept in balance with the forage demand

Rotational Stocking Method

HIGH FORAGE SUPPLY(SPRING AND EARLY SUMMER)

GRAZE HALF – HARVEST HALF

CUTFIRST

FORHAY

ORSILAGE

CUTFIRST

FORHAY

ORSILAGE

LOW FORAGE SUPPLY(MID-SUMMER AND FALL)

GRAZE ALL

15 day rest period in the Spring30 day rest period in the Summer

A High Value Pasture is:“A unit or area of land on which exists a suitable amount, type and distribution of vegetation that when utilized with a sufficient level of management complements or meets the nutritional requirements of the resident livestock for as long a time period is as possible.”

In other words, there is enough good quality, palatable forage available for animals to perform well!

Low Value PastureHigh In Forage Quality – Low In Forage Quantity

0

2

4

6

8

10

12

14FO

RA

GE H

EIG

HT (

INC

HES)

Low Value PastureHigh In Quantity – Low In Quality

FORA

GE

HEI

GH

T (IN

CHES

)

0

2

4

6

8

10

12

14

High Value PastureHigh Forage Yield – High Forage

QualityFO

RA

GE H

EIG

HT (

INC

HES

)

0

2

4

6

8

10

12

14

Pasture plants are alive and actively growing.

They change in yield and quality every day and even over the course of a few hours.

Time

3 PHASES OF PASTURE GROWTH3 PHASES OF PASTURE GROWTH

0

2

4

6

8

10

12

14

16

18

20PHASE IIISTEMMY

OVER-MATURE

PHASE ILEAFY

IMMATURE

PHASE IILEAFY

MATURE

0 5 10 15 20 25

NUMBER OF DAYS GROWTH0 10 20 30 40 50SUMMER

SPRING

LOW

Q

U

A

N

T

I

T

Y

Q

U

A

N

T

I

T

Y

HIGH LOW

HIGH

Q

U

A

L

I

T

Y

Q

U

A

L

I

T

Y

YOUNG VEGETATIVE PLANT

LEAF PLANT CELL

CELL CONTENTS ± 80%

CELL WALL± 20%

OLD OVER-MATURE PLANT

LEAF PLANT CELL

CELL CONTENTS ±20%

CELL WALL± 80%

RELATIVE PROPORTION OF FIBER COMPONENTS

PROTEIN SUGARS40% CELLULOSE

50% HEMICELLULOSE

10% LIGNIN

OLD OVER-MATURE PLANT

YOUNG VEGETATIVE PLANT

PROTEIN SUGARS20% CELLULOSE

30% HEMICELLULOSE

50% LIGNIN

Typical Forage Quality

NUTRIENT PASTURE HAY HAYLAGE

Dry Matter % 20-25 88-92 35-40

Crude Protein % 20-30 8-14 14-20

Net EnergyG, Mcal/lb .50-.60 .40-.50 .45-.55

ADF%* 20-30 30-40 30-40

NDF%** 40-50 55-65 45-55

* Acid Detergent Fiber – cellulose + lignin

**Neutral Detergent Fiber – hemicellulose + cellulose + lignin

Protein• Protein from pasture > animal req’ts• 20 – 30% crude protein from pasture• Dairy cow needs 16-17%• Beef, sheep, etc. need 12-14% depending on production phase

• Protein from pasture > rumen bacteria req’ts• 70 – 80% degradability

• Feeding energy supplements can help to dilute protein

How Excess Degradable Protein Wastes Energy

Degradable Protein

Used by microbes Not used protein + carbohydrates converted to ammonia microbial protein - energy used by cows ammonia into blood

ammonia in blood to

liver energy

urea excretion liver converts to urea

Supplementation

• Dilute the pasture protein• Feed a little dry hay

• Lower protein than pasture• Substitutes for pasture intake

• Use the pasture protein• Feed a little ground corn

• Provides non-fiber carbs (NFC)• Rumen bugs use to make more bugs

Non-Fiber Carbohydrates (NFC)

• Dairy• Critical for high milk production• Caution – no grain not easy

• Beef• Only if gains are low

• Sheep, goats• Breeding, lactating w/multiples, weaned lambs or kids

• Camelids• No clear guidelines – be careful not to overfeed

Non-Fiber Carbohydrates (NFC)

• Horses• Amount depends on level of work

• Swine• Grain higher proportion of diet

• Poultry• 70-90% of diet with insects, grass, etc balance

None of these species types needs NFC’s for rumen or excess pasture protein issues

Supplementation

• Salt• Supply free-choice

• Loose vs. blocks• Self-limiting

• Mix in with grain• Limits intake

• Minerals• Can be in trace mineral salt block• May need extra selenium• Be careful of copper & molybdenum content

• Sheep and goat label• Camelids have similar toxicity problem

Kelp• Approved for organics• Source of minerals, vitamins, anti-oxidants• High iodine content

• Not problematic

• Limited research• Boosts immune system• Reduces pinkeye

Parasite Issues• Sheep and goats – major issue• Barber pole worm, brown stomach worm, coccidia, P. tenuis, flukes, tapeworms, lungworms, etc.• Dewormer resistance

• use FAMACHA and strategic deworming• Pasture management

• longer rest periods to break lifecycle – 45-60 days• graze taller forage, leave more residual

Parasite Issues• Cattle – minor issue• Roundworm, flukes, tapeworms• Same lifecycle as sheep parasites, but species specific• Dewormers typically used twice in spring – resistance issue• Young animals most susceptible – cattle become more resistant with age• Pasture management

• Young animals on “clean” pasture• Don’t overgraze

Multi-species Grazing –cattle + sheep

• Advantages• More uniform grazing of pasture• Predator protection• Parasite protection

• Disadvantages• Mineral supplementation for cattle vs. sheep/goats

• Systems• Leader-follower• Co-grazing• “Strategic rotation” for parasite control

“Strategic Rotational” Stocking Method

Sheep

CUTFIRST

FORHAY

ORSILAGE

Cattle

45-60 day rest period for sheep20-30 day rest period for cattle

Multi-species Grazing -poultry + ruminants

• Advantages• Poultry break up manure, spread nutrients• Poultry eat fly larvae, snails (?)• Reduced grain consumption

• Disadvantages• Labor-intensive if using pens• Messy if true “free-range”• Predator problems

Health Considerations• Pasture provides health benefits

• Boosts immune system – reduces stress

• Vitamins A & D, natural minerals & antioxidants, medicinal plants

• Sunshine, fresh air, naturally comfortable environment, clean, soft footing, exercise

• Need to manage grazing well before health improves

Summary• Managed pasture is beneficial for both health and nutrition of all

species

• If pasture main source of feed, must be managed for quality and quantity

• Parasite management needed with small ruminants

• Benefits to grazing different species together

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