FAO ANIMAL PRODUCTION AND HEALTH PAPER 135
Roughage utilization in warm climates
Institut national de la recherche agronomique (INRA)
Centre de recherche de Clermont-Ferrand-Theix
Institut national agronomique (INAT)
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1. RECALL OF THE ANATOMY OF THE DIGESTIVE TRACT OF RUMINANTS AND THE DIGESTIVE UTILISATION OF LOW QUALITY FORAGES
1.1. Anatomy of the digestive tract
1.2. The importance of microbes to ruminants
1.3. Digestive utilisation of low quality forages
1.3.1. Chemical composition
1.3.2. Digestive utilisation
188.8.131.52. Conditions for good digestive utilisation
1.3.3. The nutritional value, as related to intake and digestibility
1.4. Conclusions and strategies which allow maximum value to be obtained from low quality forages
2. FORAGE TREATMENT
2.1. Physical treatment techniques
2.1.1. Mechanical treatment
2.1.2. Thermal treatment by steam
2.2. Biological treatment
2.3. Chemical treatment
3. AMMONIA TREATMENT
3.1. Ammonia as a reagent
3.2. Success factors for ammonia treatment
3.2.1. Amount of ammonia
3.2.2. Temperature and length of treatment
3.2.3. Effect of ambient humidity on ammonia treatment
3.2.4. The nature of the forage to treat
3.3. Practical applications
3.3.1. Practical treatment methods
3.3.2. Examples of practical applications
4. UREA TREATMENT
4.1. Basic principles
4.2. Key success factors for urea treatment
4.2.1. Urease presence
4.2.2. Urea application rates
4.2.3. The amount of water to add
4.2.4. Ambient temperature and the length of treatment time
4.2.5. The initial quality of forage to treat
4.2.6. Hermetic sealing of the treatment environment
4.3. Practical considerations for urea treatment
4.3.1. Treatment and storage methods
4.3.2. Practical methods for urea treatment
4.3.3. The calendar of work for urea treatment
4.3.4. Other urea treatment methods: the use of urine
4.4. Conclusions relating to urea treatment techniques
5. EFFECTS OF TREATMENT ON FORAGES
5.1. Physical aspects
5.2. Chemical composition
5.2.1. Crude fibre content determination by Weende's Method
5.2.2. Fractionation of the carbohydrates by the Method of Goering and Van Soest
5.2.3. Nitrogen Content (N) or Crude Protein Content (N x 6,25)
5.2.4. Overall mineral content (ash)
5.3. Feeding value
5.3.1. Organic matter digestibility (OMD)
5.3.2. Crude protein
5.3.3. Ingestibility and intake
5.4. Conclusion concerning the treatments
6. FEED SUPPLEMENTS
6.1. Recall of basic nutritional principles
6.1.1. Minimum feed supplements: optimising the use of cellulose in the rumen
6.1.2. Supplements to ensure good animal production
184.108.40.206. Substitution phenomena
220.127.116.11. Consequences on the nature and the amount of complementary energy
18.104.22.168. Consequences on the nature and the amount of supplementary nitrogen
22.214.171.124. The case of treated forages
6.2. Practical applications
6.2.1. Supplements consisting only of urea
6.2.2. Mixtures of molasses and urea
6.2.3. A special case: using multinutrient blocks as a supplement
126.96.36.199. Principles for manufacturing the ingredients
188.8.131.52. Fabrication methods
6.2.4. Supplements with green forages and crop residues
6.2.5. Supplements using local byproducts
184.108.40.206. Supplements available “on the farm”
220.127.116.11. “Complete” rations designed to fully exploit the usage potential of low quality forages
6.2.6. “Classic” supplements using commercially available concentrates
7. RESULTS AND EXPERIENCES CONCERNING ANIMAL PRODUCTION AND THE UTILISATION OF LOW QUALITY FORAGES
7.1. Review of the general context
7.2. Use of multinutrient blocks
7.2.1. Case study results
7.2.2. Effects on intake and performance
7.3. Utilisation of treated forages by the animal
7.3.1. Case study results
7.3.2. The contribution of treatment towards general maintenance and well-being of the animals
18.104.22.168. Straw given as an unlimited ration
22.214.171.124. Limited stocks of straw
7.3.3. Utilisation of treated forages to achieve modest production rates
126.96.36.199. Milk production
188.8.131.52. Growth and fattening
184.108.40.206. Draft animals
7.3.4. More intensive production systems
7.4. Multinutrient blocks or forage treated with urea?
8. SOCIO-ECONOMIC CONSIDERATIONS CONCERNING THE DEVELOPMENT OF TECHNIQUES FOR IMPROVING THE VALUE OF LOW QUALITY FORAGES
8.2. Economic aspects
8.2.1. Agro-economic contexts
8.2.2. How to reduce treatment costs
8.2.3. Optimizing the quality and quantity of supplements for the treated forage
8.3. Practical considerations concerning the development of straw improvement techniques
8.4. Impact of the techniques on agricultural systems
8.4.1. Local byproducts and introduction of improved forage species
8.4.2. The impact of diffusing urea treatment techniques
8.4.3. A simple technique, supporting the development policy for animal production
9. DEBATE - QUESTIONS AND REPLIES FROM THE FIELD
11. APPENDIX 1. DIFFERENT PRACTICAL METHODS for UREA TREATMENT
12. APPENDIX 2. DIFFERENT PRACTICAL METHODS for AMMONIA TREATMENT
13. APPENDIX 3. GUIDE FOR USING TREATED FORAGES
14. APPENDIX 4. FABRICATION METHODS and GUIDE FOR USING MULTINUTRIENT BLOCKS
15. APPENDIX 5. IN CASE OF POISONING DUE TO THE UREA
16. APPENDIX 6. AVERAGE NUTRITIONAL VALUE FOR THE PRINCIPAL CROP RESIDUES AND AGRO-INDUSTRIAL BYPRODUCTS
17. APPENDIX 7. COUNTRIES WHICH HAVE ENGAGED IN ACTIONS CONCERNING TECHNIQUES FOR MAKING MULTINUTRIENT BLOCKS and TREATING STRAW WITH UREA
We would like to thank the Animal Production and Health Division of FAO, particularly the Feed Resources Group and its leader, René SANSOUCY, for being invited and given the confidence to undertake this work.
We thank all the field officers and their directors or chiefs, together with all the livestock farmers whom we have been privileged to meet during our missions in the various different countries visited. We fully appreciate the work that they have accomplished both in our presence and in our absence. We congratulate them for their interest, patience and ingenuity for which they have proven themselves through putting into practice the proposed methods in a manner best adapted to their respective local constraints. Without these colleagues, this document could have lost its realistic approach.
We thank our research, training and extension colleagues for having carefully read the document during its preparation and for giving their criticisms and suggestions for improvements. Special thanks are directed to François ACHARD for reviewing the all document and to Jean Pierre BOUTONNET and to Gérard MERCIER for their invaluable advice concerning the preparation of Chapter 8 which deals with socio-economic aspects.
Finally we have special thoughts for Messrs. Vincent de Paul RAJAONARIVONY, from Madagascar and Chim KEAVUTH, from Cambodia, deceased prematurely during or shortly after undertaking development projects in their countries. This message is addressed directly to their families to whom we offer our deepest respect and condolences.
Family livestock farming plays a determinant role in the averagely developed and developing countries from both an agro-ecological and socio-economic point of view. This is particularly the case for cattle production (zebus, bullocks) and buffalo which provide, in addition to meat and milk, traction power and manure, factors favourable to the beneficial integration of agricultural and livestock farming.
The ideal feed for ruminants is clearly green forage or good hay. Natural rangeland pasture zones (exploited by wild game) in developing or averagely developed countries are sparsely populated; they constitute an immense reserve of forage but they are only used by wandering shepherds and herdsmen near to watering points, the sedentary livestock farmers who only exploit the areas surrounding their encampments or villages and finally, the extensive farms of the ranch type belonging to large land owners, either state or private investors. This type of livestock farming only concerns a limited number of the livestock farmers within these countries.
In tropical countries and around the Mediterranean, forage is often in short supply either due to climatic or to demographic reasons, the latter particularly being the case in South East Asia. As priority is given to producing food crops for human consumption, the areas under natural forage are becoming more and more reduced, to the profit of the cultivated areas. Apart from the “developed” forage production systems which only affect about a third of the world cattle population, domestic ruminants have to resort more and more to mediocre quality forage resources which, during the dry season, are made up of crop residues (small grain cereal straw for which rice straw is the most important, stalks of sorghum, millet and maize), natural standing forages at the stage of becoming straw and highly ligneous. It is to be noted that agro- livestock farmers often collect straw from the bush by simply raking it up (Photo 1) so as to last through the “lean” period before the rains.
Ruminants, in contrast to other domestic species, are the only ones capable of taking advantage of these low quality forages, thanks to their belly, or rumen, which is a true fermentation unit.
The knowledge accumulated over the last twenty years in the domain of the physiology of the ruminant's nutrition, together with perfection of new techniques (treatments), now allow improvement of the nutritional value of these poor forages such as straw and their full exploitation by cattle and the smaller ruminants.
Much has been written on this subject but this mainly comprises scientific publications. Articles referring to development are also numerous but they are scattered and there are very few works which make an exhaustive synthesis concerning straw and low quality forages.
The objective of the present document is to place in the hands of the decision makers and, more particularly, the field officers and trainers, not a book of recipes which are normally badly used as they are generally taken completely out of their scientific and practical context, but rather a description of the various points for reflection and the tools of knowledge which will allow them to select their choices and to make appropriate technical decisions in the light of a thorough understanding of goals. Considering these aims, continuous cross referencing is recommended between the basic facts and the definitive establishment of appropriate techniques, an approach which has already been well proven in practice.
The authors have been guided in the production of this work as follows:
by referring to existing publications and from which they have endeavoured to extract the most salient points,
by recalling their own personal experiences in development projects (training/extension) in various agro-climatic regions of the world which concerned diverse animal production systems and for which they have endeavoured to present accounts which representing both stories of success and others of failure.
The common denominator is the improvement of the value of crop residues, essentially straw and natural forages which have been harvested as forage resources, so allowing the farmer to endure the dry season and, if possible, even hope for a minimum level of production (meat, milk, work) from the animals which feed off this material.
Whatever is the situation concerned, be it rice straw in the high plateaux of Madagascar, the irrigated perimeters of the Senegal or Niger rivers, the plains in Cambodia, Vietnam or Laos, straw from oats on the Bolivian high plateau, straw from barley or wheat in North Africa and the Near East, natural bush forages raked together in the Sahel region, maize stalks carefully transported from the Masaï plateau right to the coffee producing villages on the slopes of Kilimanjaro, the questions are always the same:
How can one obtain the maximum value from the straw, cereal stalks or natural forages in a way to better exploit their nutritional value and hence to improve animal production levels?
How should one supplement these low quality forages with the resources which are locally available with a minimum reliance on externally produced products which are found to be both expensive and difficult to find on the market?
Should these forages be treated or not (this question is posed in the socio-economic context of shepherds, nomads or agro-shepherds)? If the answer is yes, then which technique should be adopted? How should one utilise these treated forages so that any benefit from the treatment is not lost?