Cavali, J.

Fernandes, H. J.

Paiva, L. M.

Paulino, M. F.

Porto, M. O.

Rocha, A. A.

Silva, A. G.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Nutritional Parameters of Grazing Nursing Calves 1: Rumen Microbial Production H. J. Fernandes State University of Mato Grosso do Sul, Brazil J. Cavali Federal University of Viçosa, Brazil A. G. Silva Federal University of Viçosa, Brazil M. F. Paulino Federal University of Viçosa, Brazil A. A. Rocha Federal University of Viçosa, Brazil See next page for additional authors 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/21/9-1/29 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. Presenter Information H. J. Fernandes, J. Cavali, A. G. Silva, M. F. Paulino, A. A. Rocha, M. O. Porto, and L. M. Paiva This event is available at UKnowledge: https://uknowledge.uky.edu/igc/21/9-1/29 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　 瞯 ]45　 瞯Grasslands/Rangelands Production Systems——— Livestock Production SystemsNutritional parameters of grazing nursing calves 1 : rumen microbial productionH .J .Fernandes1 ,2 ; J .Cavali 2 ; A .G .Silv a2 ; M .F .Paulino2 ; A .A .Rocha2 ; M .O .Porto2 and L .M .Paiva1 ,21 S tate University o f Mato G rosso do Sul / FUNDECT ,A quidauana‐CERA road ,Km 12 ,A quidauana ,MS ,79200‐000 ,Braz il ,E‐mail : ike .f ernandes＠ hotmail .com ; 2 A nimal Science Department ,Federal University o f V i毕osa ,MG ,36570‐000 .Key words : calves ,milking ,grazing ,nutritional parametersIntroduction Brazil has the largest commercial cattle herd in the world .Approximately ９５％ of the meat production in thecountry came from animals on pasture .In spite of this ,little has been studied about the effects of the interaction between pastureconditions ,animal life phase and fed supplement .Protein supplementation has been widely used because it potential to improvethe pasture digestibility .Finally ,although the milking phase is responsible for up to ５０％ of the final weight of beef cattle ,it hasbeen little studied .The objective of this study was to evaluate the response of ruminal microbial production in nursing calvesreceiving different protein levels supplement under Brazilian autumn conditions .Materials and methods This work was carried out in the region of Vi毕osa ,MG ,Brazil .A total of ５２ Nellore beef calves withinitial age of １００ days and initial weight of １２９ kg were used in the study .The animals with their mothers were separated intofour groups that received different concentrate supplement in a �Creep‐Feeding" system .The animals were kept in pasturesformed with Brachiaria decumbens Stapf .At every seven days , the lots were rotated among the pastures .The evaluatedsupplements were : ad libtum mineral salt ( control treatment ) ,and rations with ８ and ３２％ of crude protein ( CP) formulatedwith corn and soybean meal ,daily fed at １ .２ kg / animal . The pastures were sampled every ２８ days ( McMeniman ,１９９７) .On the６５th day of the experiment ,spot urine samples were collected to determine the daily purine derivatives excretion as suggested byValadares et al .(１９９９ ) .The significance level used was ５％ .Results and discussion The pasture conditions ( Figure １ ) showed that were mainly qualitative variation from March to May ,withchanges in the proportions of components of the pasture ( green or dry leaves and stems) ,but without change in the availabilityof total dry matter .On the other hand ,in June ,parallel to the reduction in DM availability ,there was also a reduction in theproportion of green materials ,especially leaves ,with prevalence of dry materials .No differences were found for daily excretion ofUric Acid ( Table １) ,whereas the excretion of Alantoine ,and consequently total Purine derivatives ,was affected by the type ofconcentrate supplement fed to the animals .Data showed a larger production of microbial protein by animals supplemented withrations with low protein level .As the protein level in the supplement increases ,or when the animals are supplemented withmineral salt only ,the production of microbial protein is reduced .This can be explained by the largest level of starch in therations with low protein level .The starch may have stimulated a larger ruminal microbial grow th in earlier ages .　 　 Figure 1 V ariations ( kg DM / ha ) in totalavailability ( Tot ) and component ( greenleaves‐GL ,dry leaves‐DL ,green stems — GS ,and dry stems — DS ) o f pasture during theex perimental period .Table 1 Urine volume (UV ) ,Uric A cid (UA ) ,A lantoine (A L ) and totalPurine ( T P) excretions ,and microbial N itrogen ( Nmic ) and CrudeProtein (CPmic) p roductions o f sup p lemented nursing calves .Protein level in Suplements１ ЁSalt ８％ CP ２２％ CP ３２％ CP CV ( ％ )UV２ ２ �.９４b ４ 照.８６a ３ 崓.３２ab ２ x.８２b ５８ T.７UA３ ２  .１７a ３ 照.７４a ２ è.３６a ２ |.４８a ７１ T.６AL３ ３５ �.７７b ５２ 照.６１a ４４ 崓.４４ab ３９ x.６５b ３４ T.８TP３ ３７ �.９４b ５６ 照.３５a ４６ 崓.８６ab ４２ x.１４b ３５ T.２Nmic４ １６ �.３９b ３１ 照.４６a ２３ 崓.０２ab １９ x.０６b ５７ T.９CPmic４ １０２ �.４２b １９６ 照.６０a １４３ 崓.８７ab １１９ x.１６b ５７ T.９Means in the same row followed by the same letter are not significantdifferent by the t test ( p ＜ ０ .０５ ) ;２ １／day ; ３ mmol/ day ; ４ g / day .Conclusions The use of concentrated supplements with until ２２％ of crude protein was capable to increase the ruminal microbialproduction in grazing nursing calves under autumn conditions in Brazil .It is recommended further researches to evaluate theeffects of protein supplementation of grazing nursing calves on their future productive capacity .ReferencesMcMeniman ,N .P .１９９７ .Methods of estimating intake of grazing animals . In : Reuni本o Anual da Sociedade Brasileira deZootecnia ,３４ ,Juiz de Fora .A nais . . .Juiz de Fora : SBZ . p .１３１‐１６８ .Valadares ,R .F .D . ; Broderick ,G .A . ; Valadares Filho ,S .C .et al . ,１９９９ .Effect of replacing alfalfa silage with high moisturecorn on ruminal protein synthesis estimated from excretion of total purine derivatives . Journal o f Dairy Science ８２ ( １１ ) :２６８６‐２６９６ .

Nutritional Parameters of Grazing Nursing Calves 1: Rumen Microbial Production

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Nutritional Parameters of Grazing Nursing Calves 1: Rumen Microbial Production

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