Hunt, L. P.

Petty, S. R.

Poppi, Dennis P.

White, Andrew I.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress The Use of Faecal NIRS to Monitor Diet Quality Different Grazing Systems in Tropical Savannas Andrew I. White Heytesbury Beef, Australia L. P. Hunt CSIRO, Australia S. R. Petty Heytesbury Beef, Australia Dennis P. Poppi The University of Queensland, 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/21/3-1/39 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. 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　 瞯 ]483　 瞯Grasslands/Rangelands Resources and Ecology ——— Soil‐Plant‐Animal InterrelationshipsThe use of faecal NIRS to monitor diet quality different grazing systems in tropical savannasA . White 1 ,2 ,3 , L .P . H unt3 , S .R . Petty 1 and D .P . Pop p i2 . Heytesbury Bee f 1University o f Queensland2 , CS IRO Sustainable Ecosystems3 PMB 44 W innellie , N T , A ustralia 0828 .E‐mail :andrew .i .white＠ csiro .auKey words : animal nutrition , NIRS , tropical savannas , grazing systemsIntroduction Nutrition is the major factor influencing animal production in grazing systems , however it is very difficult tomonitor in extensive systems . This is especially so in northern Australia which has distinct wet and dry seasons , large paddockswith highly heterogeneous pastures and the likelihood for selective grazing . Faecal NIRS is one method to monitor diet qualityin these extensive systems ( Givens et al . , １９９７) . Here we present data that illustrates the considerable seasonal differences innutrition across four different grazing systems and discuss this in relation to collection methods and inter‐animal variation thatoccurs .Materials and methods As part of a large paddock scale study investigating aspects of grazing management in the tropicalsavannas of northern Australia , faecal samples were collected monthly to determine diet quality through NIRS . Grazing systemsinvestigated included set stocking ( SS) , set utilisation ( SU ) , wet season spelling (WSS) and cell grazing ( CG) . Twenty freshfaecal samples were ground‐collected from each treatment and aggregated , with a representative sample removed , dried at ６０ ℃for ４８ hours and analysed by NIRS . Additional opportunistic collection and analysis also occurred .　 　 Figure 1 Crude p rotein levels f rom f our di ff erent graz ing systems .Results and discussion Figure １ shows thedietary crude protein figures from the２００４ to ２００７ faecal NIRS samples in thedifferent grazing systems . ANOVAanalysis showed there was no significantdifference between the grazing systems atthe ９５％ confidence level . The mainconclusion that can be drawn is thatseason was the dominant factorinfluencing animal nutrition .The mean monthly figures providedvaluable data to inform overall nutritionmanagement . However , by aggregatingthe samples to provide means alone , thepotential value of the data is reduced as nomeasure of variation is provided .An opportunistic collection occurred inApril ２００６ with between ２９ to ３１ samplescollected from cattle within each of thedifferent grazing systems . The sampleswere not aggregated and means of dry matter digestibility and crude protein were generally similar to the routine monthlysamples . However for CG , the mean of the non‐grass component of the diet in the opportunistic samples was ２０％ ( range２４％ ) compared with the routine monthly collection figure of ４０％ . Across the grazing systems the non‐grass component of thediet varied from ２０％ ( WSS ) to ５０％ ( SU ) . Over the long‐term , this observed variability may have proved decisive indifferentiating between the different grazing systems .Conclusions Rainfall had a marked influence on diet quality as expected . Across the trial , no significant effect of grazing systemon mean diet quality was observed . However , collection and analysis of individual faecal material within each grazing systemindicated distinct variations between animals for a number of dietary factors , probably reflecting the variability in individualanimal choice of areas grazed within the large paddocks and grazing systems employed . While significantly different levels ofavailable protein were not observed in the different grazing systems , consideration of the variability in other dietary factors mayhave proved decisive in an analysis of the grazing systems .ReferenceGivens , D .I . , De Boever , J .L . and Deaville , E .R . ( １９９７ ) . The principles , practices and some future applications of nearinfrared spectroscopy for predicting the nutritive value of foods for animals and humans . Nutrition Res . Rev . １０ : ８３‐１１４ .18 16 - · ¢--· wet season spell --set stock ........ cell grazing -+-set utilisation 20% ~ 14 ~ C: 12 :§ 0 10 ... Cl. (I) 8 "C :::l ... 0 6 4 2 0 wet I dr wet I dr wet dr wet I dr 'SI" 'SI" '<I" '<I" 0 0 9 0 c ,!_ "S 13 (U 0.. --, <t: --, 0 I!) I!) I!) I!) <D <D <D <D r--- r--- r---0 0 9 0 0 0 9 0 0 0 9 c ,!_ ::J _,!, c ,!_ ::J _,!, c ,!_ "S 0.. u 0.. u 0.. (U <t: --, 0 (U <t: --, 0 ro <t: --, --, --, --, date 

The Use of Faecal NIRS to Monitor Diet Quality Different Grazing Systems in Tropical Savannas

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The Use of Faecal NIRS to Monitor Diet Quality Different Grazing Systems in Tropical Savannas

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