Donaghy, Danny J.

Rawnsley, Richard P.

Roche, J. R.

Turner, Lydia R.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XXI International Grassland Congress / VIII International Rangeland Congress Changes in Herbage Quality of Cocksfoot, Prairie Grass and Tall Fescue during Regrowth Lydia R. Turner University of Tasmania, Australia J. R. Roche University of Tasmania, Australia Danny J. Donaghy University of Tasmania, Australia Richard P. Rawnsley University of Tasmania, Australia 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/21/15-2/47 The XXI International Grassland Congress / VIII 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 744　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　Grasslands/Rangelands Production Systems ——— Forage Quality ,Conservation and UtilizationChanges in herbage quality of cocksfoot , prairie grass and tall fescue during regrowthL .R . Turner 倡 , J .R . Roche , D .J . Donaghy and R .P . RawnsleyTasmanian Institute o f Agricultural Research , University o f Tasmania , Burnie Tasmania倡 Corresponding author e‐mail : Lydia .Turner ＠ utas .edu .auKey words : herbage quality , regrowthIntroduction There has recently been increased interest in alternative perennial grass species such as cocksfoot ( Dactylisglomerata L .) , prairie grass ( Bromus willdenowii Kunth .) and tall fescue ( Festuca arundinacea Schreb .) , with researchfocusing on the management requirements and potential role of these species within intensive grazing systems . The aim of thisdesktop study was to review and compare the changes in herbage quality of cocksfoot , prairie grass and tall fescue duringregrowth .Materials and methods Herbage quality data for cocksfoot [ cv . Porto ; Rawnsley et al . ( ２００２ ) ] , prairie grass [ cv . Matua ;Turner et al . ( ２００６ ) ] and tall fescue [ cv . Advance ; Donaghy et al . ( ２００７ ) ] were utilised from three glasshouse studiesconducted at the University of Tasmania , between １９９９ and ２００４ . In each glasshouse study , treatments consisted of onepreliminary harvest followed by five sequential harvests when each new leaf had regrown , up to the ５‐leaf stage (５ live leavesper tiller) . Leaf tissue was collected at each harvest event and analysed for acid detergent fibre ( ADF) , neutral detergent fibre( NDF) , crude protein ( CP) and digestible dry matter ( DDM) . Metabolisable energy ( ME) was subsequently calculated usingthe equation : ME ＝ (０ .１７ x DDM) ‐ ２ . Based on visual assessment of mean data for trends , linear and quadratic contrasts ofquality parameters on leaf stage were undertaken for individual replicates . The slope ( m ) and intercept ( c ) of the linearcontrast for each replicate were extracted and analysed using the statistical procedures of Genstat ( Version ９ .１ , LawesAgricultural Trust , distributed by VSN) , with replicate as the random effect and forage species as the fixed effect .Results and discussion The mean data showed that the herbage quality of all three species follow expected trends , with leaf CPand ME decreasing ( P ＜ ０ .００１ ) and NDF and ADF increasing ( P ＜ ０ .００１ ) with regrowth . There was a significant ( P ＜ ０ .０１ ) difference between species for rate of change of all herbage quality parameters , with tall fescue exhibiting the most rapidrate of decreasing CP and ME and increasing NDF and ADF with regrowth . For example , while the ME of cocksfoot andprairie grass decreased at a rate of ０ .０４８ and ０ .０９９ MJ/ kg DM respectively with each additional leaf stage , the ME of tallfescue decreased at a rate of ０ .４９８ MJ/ kg DM . Cocksfoot and prairie grass displayed similar rates of change in CP , ME andNDF with regrowth , while the ADF of cocksfoot increased at a faster ( P ＜ ０ .０５ ) rate than for prairie grass .Table 1 Mean slope (m) and intercept ( c) o f the linear contrast o f the quality parameters CP , ME , NDF and ADF on lea fstage , with associated F values and least signif icant dif f erences ( LSD) .CP ME NDF ADFm c m c m c m cCocksfoot ‐２ .１２ ３４ .９１ ‐０ .０４８ １１ .５４ ０ .６２ ５４ .３９ １ .７７ ２２ .２９Prairie grass ‐２ .６０ ３６ .７５ ‐０ .０９９ １２ .１７ ０ .９２ ５３ .５１ １ .３８ ２０ .３９Tall fescue ‐４ .５９ ２７ .７６ ‐０ .４９８ １１ .８７ ２ .９３ ４７ .７６ ３ .３０ １９ .１３F value ０ .００２ ＜ ０ .００１ ＜ ０ .００１ ＜ ０ .００１ ＜ ０ .００１ ＜ ０ .００１ ＜ ０ .００１ ＜ ０ .００１LSD ( P ＝ ０ .０５ ) １ .２１ ２ .６６ ０ .０６０ ０ .１８ ０ .５９ １ .８７ ０ .３７ ０ .９８Conclusions While a comparison of absolute herbage quality values across different species and studies must be carried out withcare , the use of leaf stage as a developmental indicator and comparison of rates of change in this approach provides objectiveinsight into the relative changes in herbage quality of the alternative perennial grass species cocksfoot , prairie grass and tallfescue .ReferencesDonaghy , D .J . , Turner , L .R . , Adamczewski , K .A . , Burkitt , L .L . , ２００７ . Effect of defoliation management on water‐soluble carbohydrate energy reserves , dry matter yields and herbage quality of tall fescue . Agronomy Journal １００ , ( InPress )Rawnsley , R .P . , Donaghy , D .J . , Fulkerson , W .J . , Lane , P .A . , ２００２ . Changes in the physiology and feed quality ofcocksfoot ( Dactylis glomerata L .) during regrowth . Grass and Forage Science ５７ , ２０３‐２１１ .Turner , L .R . , Donaghy , D .J . , Lane , P .A . , Rawnsley , R .P . , ２００６ . Changes in the physiology and feed quality of prairiegrass during regrowth . Agronomy Journal ９８ , １３２６‐１３３２ .

Changes in Herbage Quality of Cocksfoot, Prairie Grass and Tall Fescue during Regrowth

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Changes in Herbage Quality of Cocksfoot, Prairie Grass and Tall Fescue during Regrowth

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