PROCEEDINGS OF A WORKSHOP HELD AT ILCA, ADDIS ABABA, ETHIOPIA 7-10 DECEMBER 1987
Edited by
Jess D. Reed
Brian S. Capper
Paul J.H. Neate
JUNE 1988
INTERNATIONAL LIVESTOCK CENTRE FOR AFRICA
P.O. BOX 5689, ADDIS ABABA, ETHIOPIA
Correct citation: Reed J D, Capper B S and Neate P J H (Eds). 1988. Plant breeding and the nutritive value of crop residues. Proceedings of a workshop held at ILCA, Addis Ababa, Ethiopia, 7-10 December 1987. ILCA, Addis Ababa.
ABSTRACT
This document contains 12 papers on topics related to the use of crop residues as livestock feed in smallholder crop/livestock farming systems, and the role of plant breeding in maintaining or improving their nutritive value. Workshop sessions covered the role of crop residues as feed resources in smallholder crop/livestock farming systems (3 papers); factors limiting the nutritive value of crop residues (3 papers); the effect of genotype and environment on the nutritive value of crop residues (4 papers); and perspectives and implications for crop improvement programmes. A fifth section presents reports of working groups on aspects relating to the main workshop sessions, and makes specific recommendations on areas needing further research and modes for collaboration between crop and livestock research programmes.
KEY WORDS
/Crop residues//Animal nutrition//Animal feeding/Plant breeding//Smallscale farming//Mixed farming//Nutritive value//Genotype//Environment//Research/
RESUME
Le présent document contient 12 communications présentées lors d'un atelier consacré à l'utilisation des résidus de récolte comme aliments du bétail dans les systèmes de production mixte, et sur les possibilités d'amélioration de la valeur nutritive de ces résidus par la sélection. Les sessions de cet atelier ont porté sur le rôle des résidus de récolte en tant que ressource fourragère dans les systèmes mixtes (3 communications); sur les facteurs limitant leur valeur nutritive (3 communications); sur l'influence du génotype et du milieu sur cette valeur nutritive (4 communications); et sur l'intégration des critères retenus aux programmes d'amélioration des cultures. Les rapports élaborés par les différents groupes de travail vent présentés dans la cinquième partie de ce document, ainsi que des recommandations sur les axes de recherche prioritaires et sur les modalités de collaboration entre agronomes et zootechniciens.
Mots cles
/Résidus de récolte//Nutrition animale//Alimentation du bétail//Sélection végétale//Petite exploitation/ /Exploitation mixte//Valeur nutritive//Génotype//Environnement//Recherche
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Importance of crop residues for feeding livestock in smallholder farming systems
Introduction
Crop-livestock systems
Use of crop residues
Farmer decision-making
Future
References
DiscussionThe availability of crop residues in developing countries in relation to livestock populations
Introduction
Methods
Results
Conclusion
References
DiscussionThe importance of crop residues as feed resources in West Asia and North Africa
Introduction
Joint products of cropping
Shock absorbers for farming systems
Crop residues for livestock
Aggregate livestock and residues
References
Discussion
Effect of environment and quality of fibre on the nutritive value of crop residues
Introduction
Analytical systems
Tropical forages, straws and stovers
Conclusions
Reference
DiscussionIntroduction
Occurrence of phenolics in plants
Classes of phenolic compounds
Analytical methods
The role of phenolics in plants and implications for breeding programmes
Mechanism of phenolics interaction with cell constituents and their digestion
Effect of polyphenolic compounds on voluntary feed intake
Effect of polyphenolics on the sites of carbohydrate and protein digestion
Effects of plant phenolics on rumen microbial activity
Effect of polyphenolics on animal performance
Conclusion
References
DISCUSSIONPractical problems of feeding crop residues
Introduction
Post-harvest and pre-feeding constraints
Background to the reading experiments-the grazing approach
Materials and methods
Results
Discussion
Acknowledgements
References
DiscussionGeneral discussion - Session 2 Factors limiting the nutritive value of crop residues
Consistency of differences in nutritive value of straw from different varieties in different seasons
Introduction
Effect of straw variety on animal performance
Causes of differences among varieties
Differences between years and variety × year interaction
Causes of year-to-year variability and variety × year interaction
Methods of routine analysis
Conclusion
References
DiscussionGenetic variation in the feeding value of barley and wheat straw
Introduction
Materials and methods
Results
Discussion
References
DiscussionSources of variation in the nutritive value of wheat and rice straws
Introduction
Variation in the nutritive value of straws
Experimental approaches
Cell wall
Cell contents
Animal factors interacting directly with straw characteristics
Conclusions
Acknowledgements
References
DiscussionFactors affecting the nutritive value of sorghum and millet crop residues
Introduction
Sorghum
Millet
Conclusions
References
Discussion
Genetic selection for improved nutritional quality of rice straw-a plant breeder's viewpoint
Introduction
Methods
Variation in composition and in vitro digestibility
Feeding studies
Genetic selection for nutritional quality of straw
Summary
References
DiscussionEvaluating sorghum cultivars for grain and straw yield
Introduction
Joint products and production efficiency
Evaluating grain and straw
The conflict between grain and straw yield
Choosing efficient cultivars
Conclusions
References
DiscussionGeneral discussion - Session 4 Perspectives and implications for crop improvement programmes