Cover
FAO ANIMAL PRODUCTION AND HEALTH PAPER 50/2




Better utilization of crop residues and by-products in animal feeding: research guidelines
2. A practical manual for research workers




CONTENTS

Prepared by
T.R. Preston
FAO Consultant

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

M-23
ISBN 92-5-102422-7

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Via delle Terme di Caracalla, 00100 Rome, Italy.

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 1986
© FAO

Hyperlinks to non-FAO Internet sites do not imply any official endorsement of or responsibility for the opinions, ideas, data or products presented at these locations, or guarantee the validity of the information provided. The sole purpose of links to non-FAO sites is to indicate further information available on related topics.

CONTENTS

Preface
1: EXTRACTION RATES: CEREAL AND GRAIN LEGUMES
2: GUIDELINES FOR ESTABLISHING FEEDING SYSTEMS FOR RUMINANTS
 2.1 GENERAL CONSIDERATIONS
 2.1.1 Introduction
 2.1.2 Limitations to “conventional” feeding standards
 2.1.3 An alternative approach
 2.1.4 Animal response to non-conventional feed resources
 2.1.5 Nutritive value
 2.2 RELATING NUTRIENT SUPPLY TO PRODUCTIVE STATE
 2.2.1 Introduction
 2.2.2 Work
 2.2.3 Maintenance
 2.2.4 Growth
 2.2.5 Reproduction
 2.2.6 Milk production
 2.2.7 Wool or hair production
 2.2.8 Carry-over effects of balancing nutrients in early life
 2.3 PRINCIPLES OF SUPPLEMENTATION
 2.3.1 Select the basal carbohydrate-rich resource
 2.3.2 Fermentable N
 2.3.3 Highly digestible forage
 2.3.4 Bypass protein
 2.3.5 Long-chain fatty acids (LCFA)?
 2.4 CATEGORIZATION OF FEED RESOURCES
 2.4.1 Fermentable carbohydrate
 2.4.2 Fermentable nitrogen
 2.4.3 Supplements which contribute to an efficient rumen ecosystem
 2.4.4 Bypass protein
 2.4.5 Bypass starch and glucogenic precursors
 2.4.6 Long chain fatty acids
 2.4.7 Feeds and other materials with a capacity to manipulate the rumen microbial biomass
 2.5 ALTERNATIVE SOURCES OF SUPPLEMENTS
 2.5.1 Livestock excreta
 2.5.2 Legume forages and foliages from food crops
 2.5.3 Attributes of legumes as supplements
3: METHODOLOGY FOR THE EVALUATION OF FEED RESOURCES FOR RUMINANTS
 3.1 INTRODUCTION
 3.2 DEFINITION OF CROP RESIDUES AND AGROINDUSTRIAL BYPRODUCTS
 3.3 CATEGORIES OF BYPRODUCTS
 3.4 ASSESSING NUTRITIVE VALUE
 3.4.1 To determine the rate of degradation in the rumen? (Stage 1)
 3.4.2 Chemical analyses (Stage 2)
 3.4.3 Test the feed with animals (Stage 3)
 3.4.4 Parameters of rumen function (Stage 4)
 3.4.5 Animal feeding trials (Stage 5)
 3.4.6 Production trials (Stage 6)
 3.5 HOW TO MEASURE IMPROVEMENT IN NUTRITIVE VALUE CAUSED BY CHEMICAL, PHYSICAL OR BIOLOGICAL TREATMENTS
4: GUIDELINES FOR THE UTILIZATION OF BYPRODUCTS BY PIGS AND POULTRY
 4.1 INTRODUCTION
 4.2 ELABORATION OF AN INVENTORY OF BYPRODUCTS USABLE BY MONOGASTRIC SPECIES
 4.2.1 Byproducts of animal origin
 4.2.2 Byproducts of plant origin
 4.2.3 Unconventional feed resources
 4.3 THE ECONOMIC AND PRACTICAL FEASIBILITY OF UTILIZING BYPRODUCTS IN PIG AND POULTRY PRODUCTION
 4.4 DETERMINATION OF TOXIC AND HARMFUL SUBSTANCES IN BYPRODUCTS
 4.5 PROPOSED METHODS FOR TREATMENT OF BYPRODUCTS CONTAMINATED WITH TOXIC OR HARMFUL SUBSTANCES
5: EXPERIMENTAL EVALUATION OF A BYPRODUCT FOR PIGS AND POULTRY
 5.1 PRELIMINARY EVALUATION
 5.1.1 Chemical analysis
 5.1.2 Palatability and toxicity trials
 5.1.3 Determination of the optimum range of inclusion
 5.1.4 Feeding trials using target animals
 5.2 PRECISE TECHNIQUES FOR EVALUATION OF A BYPRODUCT
 5.2.1 Metabolizable energy for poultry
 5.2.2 Digestible energy for pigs
 5.2.3 Amino acids
 5.2.4 Remarks
 5.3 FEEDING TRIALS AND APPLICATION
 5.4 PRIORITIES ON TESTS AND INVESTMENTS
6: ANALYTICAL METHODS FOR CHARACTERIZING FEED RESOURCES FOR RUMINANTS
 6.1 INTRODUCTION
 6.2 FACILITIES
 6.2.1 Individual pens
 6.2.2 Other facilities
 6.3 RUMEN FISTULATION
 6.3.1 Background
 6.3.2 Principle of the method
 6.3.3 Facilities and equipment
 6.3.4 Preparation of the animal
 6.3.5 The surgery
 6.4 MANUFACTURE OF RUMEN CANNULAS FROM LOCALLY AVAILABLE MATERIALS
 6.4.1 Available materials
 6.4.2 Construction of cannulas from radiator tubing
 6.4.3 PVC cannulas
 6.5 RUMEN INCUBATIONS WITH NYLON BAGS
 6.5.1 Characteristics of the bag
 6.5.2 Sample size
 6.5.3 Preparation of samples for incubation
 6.5.4 Position of bags in the rumen
 6.5.5 Incubation times of bags in the rumen
 6.5.6 Replication of measurements
 6.5.7 Use of sheep or cattle
 6.5.8 Interpretation
 6.5.9 Characterizing the rumen ecosystem
 6.6 THE USE OF RUMEN AMMONIA CONCENTRATION TO DETERMINE WHEN UREA SUPPLEMENTATION IS NECESSARY
 6.6.1 Introduction
 6.6.2 Estimation of rumen concentration - field method
 6.6.3 Laboratory techniques for estimation of rumen ammonia
 6.7 GAS LIQUID CHROMATOGRAPHY OF VOLATILE FATTY ACIDS IN RUMINAL FLUID
 6.7.1 Column packing
 6.7.2 Method
 6.7.3 Operating procedures
 6.7.4 Preparation of rumen fluid for GLC with an internal-standard
 6.7.5 Sample preparation
 6.7.6 Calculation of total VFA concentration and VFA proportions using the internal standard method
 6.8 ACETATE CLEARANCE AS AN INDICATOR OF THE BALANCE OF ABSORBED NUTRIENTS
 6.8.1 Background
 6.8.2 Hypothesis
 6.8.3 Method
 6.8.4 Injection solution
 6.8.5 Blood samples
 6.8.6 Chemical analysis
 6.8.7 Gas-liquid chromatograph
 6.8.8 Column
 6.8.9 Calculations
 6.9 ASSAY FOR BYPASS PROTEIN IN A SUPPLEMENT
 6.9.1 Validation
 6.9.2 Preparation of formaldehyde treated casein as a standard for the wool growth assay
 6.10 CHEMICAL ANALYSIS OF FEED AND FAECES
 6.10.1 Preparation of samples
 6.10.2 Moisture
 6.10.3 Ash
 6.10.4 Kjeldahl Nitrogen determination
 6.11 COLLECTION OF RUMINAL FLUID BY OESOPHAGEAL TUBE
 6.12 TREATMENT OF STRAW AND OTHER FIBROUS ROUGHAGES TO INCREASE THE POTENTIAL NUTRITIVE VALUE
 6.12.1 The principle
 6.12.2 Wet ensiling with urea
 6.12.3 The use of animal urine to ammoniate straw
 6.12.4 Ammoniation of straw with gaseous ammonia
 6.12.5 Ammoniation of straw with aqueous ammonia
 6.12.6 Ammoniation with application of heat
 6.12.7 Ammoniation with dry chemicals
7: VILLAGE/FARM SURVEYS AND ON-FARM TRIALS
 7.1 INTRODUCTION
 7.2 ATTITUDES
 7.3 METHODOLOGY
 7.3.1 The village survey on feed supply
 7.3.2 Animal production systems
 7.3.3 Introduction of innovations
 7.4 CONCLUSIONS
8: REFERENCES

PREFACE

The purpose of this Manual is to assist researchers in developing countries, especially those in the tropics, to develop livestock feeding systems based on the available resources which are mainly crop residues, dry and/or mature pastures and agroindustrial byproducts.

The need for an alternative to the traditional methods of feed analysis was first raised at an Expert Consultation on New Feed Resources held in FAO Headquarters, Rome in November 1976. At that meeting data were presented to show that the conventional feeding standards, derived from research with feeds of temperate country origin, were of limited value when applied to the crop residues, dry pastures and sugar-rich agroindustrial byproducts which made up the feed inventory in most tropical countries.

As a follow-up to this meeting a small network involving institutions from Cameroon, Nigeria and Senegal was set up by FAO to promote research on several locally available crop residues and agroindustrial byproducts.

An FAO Seminar was organized in collaboration with the International Livestock Centre for Africa (ILCA), and held in Dakar, Senegal in September 1981. At this meeting, which addressed specifically the problems of utilizing feed resources in Africa, the first results of the Network were presented. During this discussion it became apparent that apart from the conceptual difficulties of applying in Africa the animal nutrition knowledge gained in Europe and North America, there were other serious limitations of lack of infrastructure, especially laboratory equipment and the means of servicing, coupled with irregularities in electricity supplies. Communication among researchers working with tropical feed resources was found to be another limiting factor. It was resolved to extend the activities of the original Network to other countries in Africa and to join forces with the recently formed African Research Network on Agroindustrial Byproducts (ARNAB). It was proposed that the International Livestock Centre for Africa, with its comprehensive documentation and laboratory analytical facilities, should provide the coordinating role.

The conclusions and recommendations from the Dakar meeting were that there was a need to develop more appropriate procedures for evaluating crop residues and byproducts, taking into account the limited laboratory facilities of most institutions in Africa; and the nature of the livestock production systems, where multipurpose traits such as draught power, ability to survive extended dry seasons and rural (transhumant) milk supply were of greater relevance than the technologies from industrialized countries which emphasize specialized meat and milk production.

The third meeting of the series was also organized jointly by FAO and ILCA at Addis Ababa in March 1984 and addressed the specific issue of methodologies both for feed evaluation and research on livestock feeding systems. The advantages of promoting communication among different tropical regions was emphasized by drawing on participants from Latin America, Asia and Africa to share their experiences with each other and with colleagues from Europe and North America, which have specific expertise to offer in the subject area.

The Consultation was charged with producing two documents: the Proceedings dealing with the State of the Art of research into crop residues and byproducts; and a practical manual to serve as a guide for field workers, especially those operating with minimum facilities in terms of laboratory and literature support.

Ruminants have received more attention than monogastrics. This is because, in tropical countries, they are generally the more important species from both the numerical and socio-economic viewpoints. Furthermore, their physiological adaptations enable them to harvest and digest feeds, which are not available to the monogastric species, and which ipso facto are not competitive with humans for their food supply.

The basis outline of the Manual was established by the participants of the Addis Ababa Consultation. Material for Chapters 3, 4 and 5 was provided by the Working Groups on Ruminants and Monogastrics, under the guidance respectively of Drs E.R. Orskov and N. Jayasuriya (ruminants) and M. Picard and M. Cuca (Monogastrics). Professor Frands Dolberg, although not a participant, contributed his wealth of experience in India and Bangladesh to Chapter 7 on Village and Farm Surveys and Innovations. Chapters 2 and 6 are based on material from a book “Matching Livestock Systems with Available Feed Resources” to be published by ILCA under the joint authorship of Professor R.A. Leng and the Technical Editor. Mark Powell, of the ILCA Sub-humid Programme in Kaduna, Nigeria provided the material for harvest indices. René Sansoucy, Animal Production Officer (Feed Resources), FAO, HQ made a critical review of the manuscript and his comments have been incorporated.