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International Conference on Forages Proceedings of 2nd International Conference on Forages International Conference on Forages Proceedings of 2nd International Conference on Forages Edited by: C.L.S. Ávila D.R. Casagrande M.A.S. Lara T.F. Bernardes Lavras, Brazil 2018 Published by Organizing Committee of the 2nd International Conference on Forages and University of Lavras Copyright @2018 University of Lavras All rights reserved. Nothing from this publication may be reproduced, stored in computerizing systems or published in any manner, including electronic; mechanical, reprographic or photographic, without prior written permission from the publisher University of Lavras. The individual contributions in this publication and any liabilities arising from them remains the responsibility of the authors. Printed by SUPREMA Gráfica e Editora Ltda. (32) 3551-2546 ISBN: 978.85.8179.153-1 Distributed by NEFOR – Brazilian Forage Team Departamento de Zootecnia, Universidade Federal de Lavras CP: 037, CEP: 37200000 e-mail: [email protected] Foreword The Brazilian Forage Team (NEFOR) is celebrating 20th Anniversary with a special conference. With more than 10 successful events in its history, the NEFOR organizes the second CONFOR (International Conference on Forages) with practical topics discussed by renowned Brazilian and foreign researchers. Livestock systems are so much more than a farmer simply planting a seed and rearing a cow. It takes a whole ecosystem and a host of actors to work together to produce the food we need for a population of more than seven billion people. Farming in this complex and constantly changing environment raises a host of questions and problems as each day and each season bring new challenges. As a result, farmers and ranchers are always exploring new ideas and ways of doing things better. In response to a problem or some new bit of information, you experiment with new techniques, tweak your production system, observe the results and draw a conclusion: The research takes your role as a farmer/ rancher to a whole new level. Based on that, our conference innovates again by performing not one, but three simultaneous events, including a field day. This Proceedings volume contains 12 invited papers divided into 3 sections and volunteered papers which will be presented as poster and oral session. Thank you very much for your contribution in making the CONFOR 2018 a successful scientific and practical event. The Editors Contents How Silage Inoculants Can Reduce Losses and Increase Milk Production...09 Jiang, Y.; Adesogan, A.T. Strategic addition of fibrolytic enzymes for improved performance of lactating dairy cows: A review.......................................................................................29 Arriola, K. G. New concepts on baled silage.........................................................................49 Borreani, G.; Tabacco, E. The interface of forage harvester, kernel processing, and dairy cow performance....................................................................................................75 Salvati, G. G. S.; Nussio, L. G. Milking robots under grassland farming conditions.....................................105 Hardy, G. Silagem de grãos de milho e sorgo para vacas leiteiras...............................121 Pereira, M. N. A qualidade da semente define a produtividade e a perenidade do pasto...133 Figueiredo, U. J. New Fertilizer Technologies and the Management of Soil Fertility in Pastures.........................................................................................................139 Melo, L. C. A.; Carneiro, J. S. S.; Nardis, B. O. New perspectives on forage legumes in mixed pastures..............................147 Muir, J. P.; Dubeux Jr., J. C.; Tedeschi, L. O. Challenges faced by beef producers to managing pastures and strategies for addressing these challenges..........................................................................159 Mullenix, K. Boi 777: qual é o papel da forragem neste sistema?....................................169 Siqueira, G. R.; Cidrini, I. A.; Miorin, R. L.; Oliveira, I. M.; Prados, L. F.; Resende, F, D. Use and disuse of forage in feedlot finishing diets.......................................185 Daniel, J. L. P. Abstracts........................................................................................................215 Jiang, Y.; Adesogan, A.T. HOW SILAGE INOCULANTS CAN REDUCE LOSSES AND INCREASE MILK PRODUCTION Jiang, Y.; Adesogan, A.T.1 Introduction Losses from silage Ensiling is a forage preservation process, during which lactic acid bacteria ferment water-soluble carbohydrates (WSC) to mainly lactic acid. The acid maintains a low pH that inhibits the growth of undesirable microorganisms, and the breakdown of protein and other nutrients by microbes like clostridia (Pitt and Leibensperger, 1987). During and after ensiling, losses of DM, nutrients and energy can occur due to mechanical damage during harvesting, plant and microbial respiration, deamination and proteolysis, seepage, aerobic spoilage and feedout processes (Grant and Adesogan, 2018). In one of the earlier studies on the subject, Watson and Nash (1960; cited by McDonald, 1991) conducted a survey of 800 experiments and reported an average DM loss of 16% during ensiling. Later, Bastiman and Altman (1985) reported mean DM losses of 25% and 32% for unwilted and wilted silage, respectively after summarizing 205 ensiling experiments. Average DM losses during silage production of 14 to 24% were reported in a more recent survey by Rotz and Muck (1994), though losses exceeding 30% may occur in poorly managed silages, and they can be up to 49% if yeast dominate the microbial population (McDonalds et al., 1960; Table 1). 1Department of Animal Sciences, University of Florida II International Conference on Forages 9 How Silage Inoculants Can Reduce Losses and Increase Milk Production 10 Table 1 - Silage fermentation pathways and the relevant DM and energy losses (adapted from McDonald et al., 1991). Energy Microorganism Pathway DM loss, % loss, % Homofermentative LAB Glucose/fructose → 2 lactate + 2 H2O 0 0.7 → Glucose lactate + ethanol + CO2 + H2O 24.0 1.7 Heterofermentative LAB → 3 Fructose lactate + acetate + 2 mannitol + CO2 + H2O 4.8 1.0 * → 2 Citrate lactate + 3 acetate + 3 CO2 29.7 +1.5 * → Malate lactate + CO2 32.8 +1.8 → Clostridia 2 Lactate butyrate + 2 CO2 + 2 H2 + H2O 51.1 18.4 → Yeasts Glucose 2 ethanol + 2 CO2 + 2 H2O 48.9 0.2 → Enterobacteria Glucose acetate + ethanol + 2 CO2 + 2 H2 + 2 H2O 41.1 16.6 * Same pathways for homofermentative lactic acid bacteria (LAB) II International Conference on Forages Jiang, Y.; Adesogan, A.T. Based on a 20% DM loss estimate, a $50/ton price, and production of 128.4 million tons of whole-plant corn silage in 2017 (USDA-NASS, 2017), Grant and Adesogan (2018) reported that the economic impact of corn silage DM losses alone in the US is about $1.284 billion/yr. For all stored forages, the estimate exceeds $2 billion/yr (Rotz and Muck, 1994), and this hidden cost represents a loss of potentially useful nutrients that are vital for optimizing the profitability of dairy farms. In Brazil, about 120 million tons of whole-plant corn silage is produced yearly according to a survey conducted by Bernardes (2018, unpublished data). Assuming the same DM loss percentage (20%) and a cost of R$120/ton, the economic loss derived from DM loss of corn silage in Brazil is about R$2.8 billion/yr. For sugarcane silage, based on an estimated production of 1.5 million tons a year (Nussio, 2018, unpublished data) and similar DM loss and a cost of $85/ton, the economic losses are about R$25.5 million. These substantial financial implications are often ignored or underestimated (Adesogan, 2014). McDonald et al. (1991) estimated total energy loss during and after ensiling to range from 7 to > 40 % depending upon the crop type and management. The energy loss from microbial fermentation was estimated to be 2 - 4 %, which is attributable to fermentation and activity of homofermentative and heterofermentative lactic acid bacteria, clostridia, enterobacteria and yeasts. In addition to that from microbial fermentation, energy losses from residual plant respiration, effluent production and aerobic deterioration during and or after ensiling range from 1 to 2%, 5 to >7% and 0 to >25%, respectively (McDonald et al., 1991). The relevant biochemical pathways and losses are listed in Table 1, which clearly shows why homofermentative pathways produce less losses than heterofermentative pathways. Silage inoculants Silage inoculants are freeze-dried lactic acid bacteria that are added to the forage at ensiling to facilitate the fermentation process and or improve shelf life after silo opening. The major types are homofermentative and heterofermentative bacteria. The commonly used traditional homofermentative inoculants include bacteria like Lactobacillus plantarum, L. acidophilus, Enterococcus faecium, Pediococcus acidilactici, and P. pentacaceus (Kung, 2001). However, these are now taxonomically known as facultative heterofermentative bacteria (hereafter called homofermentative bacteria or inoculants). Homofermentative inoculants ferment WSC to mainly lactic acid, which leads to a rapid decline in silage pH, lower DM losses and less proteolysis. However, such inoculants do not II International Conference on Forages 11 How Silage Inoculants Can Reduce Losses and Increase Milk Production consistently reduce aerobic spoilage and in fact by providing a substrate