Stocking ratepasture production = animal production / ha

= animal production / head * no of animal / ha

= animal production / head * stocking rate

Animal unit

400 kg Steer = 1 AU.

Calf (1-8 mo) = 0.35 AU.

Weaner (8-12 mo) = 0.4 AU.

Steer (1-2 yr) = 0.87 AU.

Breeder Cow = 2.0 AU.

Bull = 2.0 AU

40 kg Merino = 1 dse.

Wether = 1 dse.

Maiden ewe = 1 dse.

Lamb= 0.5 dse.

Breeding ewe = 1.7 dse.

Ram= 1.7 dse

dse. = dry sheep equivalent

1AU. = 8 dse.

Carrying capacity =

Grazing pressure = utilise / production

= feed demand / pasture mass

= feed demand / head * no. of animal / ha

pasture mass / ha

= no. of animal / pasture area

?

The relationship between grazing pressure or stocking rate on animal production per head and per area.

Grazing pressure

An

imal

pro

du

ctio

n /

hea

dan

imal

pro

du

ctio

n /

ha

Factors control optimum stocking rate

pasture growth rate

availability of pasture mass to animal (allowance)

nutritional quality

botanical composition & ground cover

seasonal variation

type of enterprise and animal products

Pasture growth rate rainfall (seasonal) soil fertility farm management

LW

G(k

g/h

ead

/wk

)

Pasture availability (allowance; kg/head)

Pasture availability

Kikuyu grass (Pennisetum clandestinum) sward

LWG vs N availability N < 4 kg/head LWG is negative

optimum N = 36 kg/head LWG = 0.8 kg/head/d

LW

G(k

g/h

ead

)L

WG

(kg/

ha)

Stocking rate (AU/ha)2 4 6 8 12 16

N0 N134 N336 N672

Fertilizer management on botanical composition and carrying capacity of

pasture Heteropogon contortus + Stylosanthes humilis

carrying capacity = 0.7 AU./ha

if SR = 1.1 AU./ha less pasture mass and more weed (Fimbristylis dichotoma)

if + 250 kg P / ha of Super Phosphate more pasture mass and carrying capacity = 1.2 AU./ha

Accessibility of forage to animal (Pasture allowance)

Road & walk way

Shelter & pen feeding

Continuous grazing systems vs. working hour grazing time

Drinking water : 5km for cattle, 1.5 km for small ruminants

Fencing

Nutritive value of pasture

Selective grazing = การเลื�อกก�นอาหารของสั�ตว์� เท่�าก�บเป็�น การป็ร�บป็ร�งคุ�ณภาพอาหารด้�ว์ยต�ว์

สั�ตว์�เอง Intake and digestibility are limited by nutritive value

Fertilizer input will enhance intake and nutritive value of pasture

Supplementary feed

Stocking rate vs botanical composition

Species Stocking rate (head/ha)2.5 1.2

Chloris gayana 7 17Digitaria decumbens 20 30Paspalum commersonii 5 3Paspalum dilatatum 33 13Desmodium uncinatum 0 1Desmodium intortum 1 14Lotononis binensii 2 1Trifolium repens 9 5others 22 16

Effect of SR on BC of shade intorelant spp.Attribute SR (AU./ha)

3.3 2.5 1.7

LWG (kg/ha) 117 118 119

Pasture yield (kg/ha)

Total 2 170 2 850 3 170

S. humilis 1 640 1 920 1 840

% legume 75 67 58

N yield (kg/ha) 41 48 49

% N in pasture 1.88 1.68 1.54

Mott (1960)’s model

Grazing pressure

An

imal

pro

du

ctio

n /

hea

d

An

imal

pro

du

ctio

n /

ha

Low SR Optimum Over

Under grazing Optimum Over

LWG = a - b (SR)

a reflect to nutritive value of pasture and genetic potential of animal

b reflect to pasture mass or yield or allowance or response of pasture to stocking rate

LW

G (

kg/

ha)

Stocking rate (AU./ha)

.5 1 2 3 4 5 6

Yh = a SR - b SR 2

Sward structure Intake , Eadible or utilizable = < pasture mass or

yield Sward density = structure = bulk density = yield/

area/height of pasture Animal will selective graze at top of sward, then if f

orced by high SR or longer interval it will graze pasture of lower quality hence bite size and rate will be affected, since these depend on bulk or sward density

Pasture utilization period

Rest period– regrowth

– weed control

– irrigation

– fertilizer application

– flowering and seed production

– altering life cyle of parasite

Grazed / cut period– defoliation regimes– trampling– excretion– seasonal– continuous parasite

cycle

General guide for optimum stocking rate(after Jones, et al. 1984)

Total Subtropical Tropical

rainfall tropical temperate N short wet long wet N

(mm/yr) legume legume fertilizer season season fertilizer

750 0.8-1.5 1.0-2.5 2-4 0.3-1.0 - -

1000 1.0-3.0 1.5-3.5 3-6 0.5-1.5 1.5-3.0 3-6

1500 1.5-3.0 2.0-4.0 4-7 0.7-1.5 2.0-4.0 5-8

2000 2.0-4.0 2.0-5.0 5-8 1.0-2.0 3.0-4.0 7-10

Grazing systems Continuous ระบบจำ!าเจำ หร�อ ต�อเน�"อง Rotational ระบบหมุ�นเว์$ยน Repeated seasonal ระบบป็ระจำ!าฤด้& Strip ระบบเป็�นแถบ Creep ระบบแบ�งขนาด้สั�ตว์� Defered ระบบชะลือการแท่ะเลื*มุ Zero ต�ด้ให�สั�ตว์�ก�น

Stocking rate & grazing system

Set stock

Variable stock

– buying

– selling

Continuous grazing system

Rotational grazing system

Continuous vs rotational grazing system on LWG (kg/ha/d) of beef grazed Panicum maximum an

d Macroptilium atropurpureum cv.Siratro sward

Continuous 14 days on 7 days on

28 days off 35 days off

Dry season 1.14 1.03 0.77

Wet season 1.42 1.38 1.28

3-5 days on 7 days on

14 days off 28 days off

Dry season 1.30 0.95

Wet season 2.20 2.28

When to graze / rest ? Stock in (graze)

– high pasture growth rate

– not in poor conditions

– have longest rest period

Stock out (rest)

– low pasture mass harmful to the regrowth

– low nutitional status

– poor animal growth

– invasion of weeds

Why rest or rotation the pasture ?

to control botanical composition

to have seed set and seed soil reserved

to control parasite life cycle

for other animal management eg. vaccination, sanitation, reproductive management (AI)

for easier farm amnagement eg. fertlizer application, hay or silage making, fencing

Electric fence Three types of fencing : perimeter, permanen

t subdivision, and temporary subdivision voltage generator (energizer) wire fencing, Polywire, Hot-tape, Electric nett

ing, Hi-tensile wire, Barbed wire post is it cheap ? design of the fencing and paddock system

Electric fence

Energizer (voltage generator)Joule = 1 watt/sec

220 v. in

corner postgate post

controller switch

จำะเลื$,ยงสั�ตว์�ได้�เท่�าใด้ ( ก$"ต�ว์ ต�อไร�) ?

บ�ญฤา ว์�ไลืพลื 2526( ) ท่ราบผลืผลื�ตพ�ชอาหารสั�ตว์�(กก/ไร�/ป็0)

ท่ราบขนาด้ของสั�ตว์� (กก/ต�ว์ ) แลืะ อ�ตราการเจำร�ญเต�บโต (กก/ต�ว์/ว์�น)

ท่ราบคุว์ามุต�องการอาหารของสั�ตว์� 3( % ของน!,าหน�กต�ว์)

คุ!านว์น จำ!านว์นสั�ตว์� หร�อ อ�ตราสั�ตว์�

How to determine paddock size and number for rotational grazing system

(After Gerrisk, JR. 1992) How many animal and what are their size ?

Feed requirement (cow / bull = 2.5% of body weight , and calf = 3.0% of body weight)

What is the desired % of pasture utilization (eg. 70%)

What is the pasture yield (eg. 3000 kg/rai)

How would you like the paddock to be rotated (eg. 7 days graze 35 days rest)

Determine the size and number of required paddock