Chen, Guowei

Shun, Xiao

Wang, Deli

Wang, Ling

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress The Role of Functional Plant in Sheep Foraging Ling Wang Northeast Normal University, China Guowei Chen Northeast Normal University, China Xiao Shun Northeast Normal University, China Deli Wang Northeast Normal University, China Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/9-3/47 The 21st International Grassland Congress / 8th International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 瞯 ]64　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　Grasslands/Rangelands Production Systems——— Livestock Production SystemsLive weight gain of beef cattle steers on Panicum maximumcv .Tanzania subjected to intensitiesof rotational grazingD .Nascimento Jr .1 , G .S .Di f ante2 ,V .P .B .Euclides2 ,S .C .da Silv a3 ,R .A .Torres21 Universidade Federal de V i毕osa ,V i毕osa ,MG ,Brasil ,email : domicio＠ u f v .br ,2 Embrapa‐Gado de corte ,Caixa Postal 154 ,Campo Grande ,MS ,79002‐970 ,Brasil ,3 Universidade de S本o Paulo ,Piracicaba‐SP ,BrasilKey words :Grazing frequency ,grazing intensity ,sward light interception ,morphogenesisIntroduction Herbage intake and animal performance increase with increasing sward height ,herbage mass ,post‐grazing residueand herbage allowance to a certain limit .This increase tends to a maximum which is specific for a given animal species andcategory ,and defined by the ability of animals to process and ,or digest the consumed herbage .Identification of the swardcondition at which that response happen allows its comparison with ideal sward targets for efficient harvest of the producedherbage ,resulting in the definition of sward target based management strategies that take into account plant and animalrequirements .Material and methods T reatments corresponded to intensities of rotational grazing characterized by two post‐grazing heights ,２５and ５０ cm ,both associated to common a pre‐grazing condition of ９５％ canopy light interception ( LI ) by the sward duringregrow th .T reatments were designated as : 25 ＝ ２５ cm post‐grazing height and ９５％ LI pre‐grazing ; 50 ＝ ５０ cm post‐grazingheight and ９５％ LI pre‐grazing .A group of ６０ Nelore steers from the EMBRAPA‐Gado de Corte herd ,with approximately １２months of age and initial weight ２２１ kg ,were used for estimating live weight gain .From these ,２４ test‐animals were selected ,with an initial weight of ２３２ kg ,and assigned to four groups containing ６ animals each ,which were randomly distributed to fourexperimental units ( two treatments and two replications) .These experimental units comprises ６ paddocks of ０ .２５ ha each ,andwere conceived to function as a self‐contained unit ( farmlet) .Table 1 Sward height and herbage mass o f tanz ania guineagrass sub jected to intensities o f rotational stocking .Variables T reatments２５ Ζ５０ 6Sward height pre‐grazing ( cm) ６５ ,０ 栽６８ ,４ dSward height post‐grazing ( cm) ２６ ,５ 栽４７ ,８ dHerbage mass pre‐grazing ( kg / ha of DM ) ７１３０ a ８６００ aHerbage mass post‐grazing ( kg / ha of DM ) ３８１０ b ５０８０ aADG ( g / day) ６６４ b ８０１ aLWG/ ha ５６０ 浇６００ MFeed conversion efficiency ( kg DM / kg weight gain) １０ ,３ a ８ ,９ bSR ( animals of ３００ kg / ha) ６ ,１ a ４ ,９ bMeans followed by the same letter in lines are not different ( P ＞ ０ .０５)Results Sward height and herbage mass pre and post‐grazing are shown in Table １ .Targets of LI pre‐grazing and post‐grazingheights were adequately maintained throughout the experimental period .The post‐grazing height of ２５ cm was relatively harderto maintain than the ５０ cm one ,a result of the resistance animals had to graze the bottom stratum of the swards ,whichcontained only １１ .５％ of leaves .The amount of live weight produced per hectare is a function of the individual weight gain persteer and of the stocking rate used .Swards grazed to ５０ cm resulted in higher daily weight gain and lower stocking rate thanswards grazed to ２５ cm of post‐grazing height ,with no difference in weight gain per hectare .Feed conversion efficiency ,however ,was better for the ５０ cm than the ２５ cm post‐grazing height treatment .Conclusions Grazing intensity influence individual performance and weight gain per unit area , affecting feed conversionefficiency .Definition of post‐grazing height targets when planning rotation grazing strategies must be a function of targets ofanimal performance and productivity set according to the specific objectives of each system of production .ReferenceDIFANTE ,G .S .Desempenho de novilhos ,comportamento ingestivo e consumo voluntário em pastagem de �Panicum maximum"Jacq .cv .Tanzania .Vi毕osa : Universidade Federal de Vi毕osa ,２００５ .７４p .Thesis (Doctor o f Science )‐Universidade Federal deV i毕osa ,２００５ .Adviser :Prof .Domicio do Nascimento Júnior .

The Role of Functional Plant in Sheep Foraging

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The Role of Functional Plant in Sheep Foraging

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