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Stocking rate. pasture 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.
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Stocking rate pasture 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
Animal production / head animal production / ha The relationship between grazing pressure or stocking rate on animal production per head and per area. Grazing pressure
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 Pasture availability • rainfall (seasonal) • soil fertility • farm management LWG (kg/head/wk) Kikuyu grass (Pennisetum clandestinum) sward Pasture availability (allowance; kg/head)
LWG vs N availability • N < 4 kg/head LWG is negative • optimum N = 36 kg/head LWG = 0.8 kg/head/d LWG (kg/head) N0 N134 N336N672 LWG (kg/ha) 2 4 6 8 12 16 Stocking rate (AU/ha)
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 = การเลือกกินอาหารของสัตว์ เท่ากับเป็น การปรับปรุงคุณภาพอาหารด้วยตัวสัตว์เอง • 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) 2.51.2 Chloris gayana 717 Digitaria decumbens 2030 Paspalum commersonii 53 Paspalum dilatatum 3313 Desmodium uncinatum01 Desmodium intortum114 Lotononis binensii21 Trifolium repens95 others 2216
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 Animal production / head Animal production / ha Under grazing Optimum Over Low SR Optimum Over Grazing pressure
Yh = a SR - b SR 2 LWG (kg/ha) 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 .5 1 2 3 4 5 6 Stocking rate (AU./ha)
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 forced 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 • Grazed / cut period • defoliation regimes • trampling • excretion • seasonal • continuous parasite cycle • Rest period • regrowth • weed control • irrigation • fertilizer application • flowering and seed production • altering life cyle of parasite
General guide for optimum stocking rate(after Jones, et al. 1984) Total Subtropical Tropical rainfall tropical temperate Nshort wet long wet N (mm/yr) legume legume fertilizerseason season fertilizer 750 0.8-1.5 1.0-2.5 2-40.3-1.0 - - 1000 1.0-3.0 1.5-3.5 3-60.5-1.5 1.5-3.0 3-6 1500 1.5-3.0 2.0-4.0 4-70.7-1.5 2.0-4.0 5-8 2000 2.0-4.0 2.0-5.0 5-81.0-2.0 3.0-4.0 7-10
Grazing systems • Continuous ระบบจำเจ หรือ ต่อเนื่อง • Rotational ระบบหมุนเวียน • Repeated seasonal ระบบประจำฤดู • Strip ระบบเป็นแถบ • Creep ระบบแบ่งขนาดสัตว์ • Defered ระบบชะลอการแทะเล็ม • Zero ตัดให้สัตว์กิน
Stocking rate & grazing system • Set stock • Variable stock • buying • selling • Continuous grazing system • Rotational grazing system
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 Continuous vs rotational grazing system on LWG (kg/ha/d) of beef grazed Panicum maximum and Macroptilium atropurpureum cv.Siratro sward
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, permanent subdivision, and temporary subdivision • voltage generator (energizer) • wire fencing, Polywire, Hot-tape, Electric netting, Hi-tensile wire, Barbed wire • post • is it cheap ? • design of the fencing and paddock system
Electric fence 220 v. in Energizer (voltage generator) Joule = 1 watt/sec controller switch gate post corner post
จะเลี้ยงสัตว์ได้เท่าใด (กี่ตัว ต่อไร่) ? บุญฤา วิไลพล (2526) • ทราบผลผลิตพืชอาหารสัตว์ (กก/ไร่/ปี) • ทราบขนาดของสัตว์ (กก/ตัว) และอัตราการเจริญเติบโต (กก/ตัว/วัน) • ทราบความต้องการอาหารของสัตว์ (3% ของน้ำหนักตัว) • คำนวน จำนวนสัตว์ หรือ อัตราสัตว์
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