Small-scale livestock production plays an important role in developing countries. Nevertheless, it is more and more constrained to resort to the utilization of feed resources such as crop residues (straw from rice, wheat, …, stalks of sorghum, millet, maize, …) and dry and fibrous natural forages raked together in order to ensure dry season feeding (particularly, at the end of the season). This occurs because small-scale livestock production can continue to develop only if it does not compete with food crops which take priority over forage crops in the fields.
These feeds, coming from old plants, have only low nutritional value. They are rich in lignified fibre (cell matter) and thus of low and slow digestibility. They are weak in protein content, minerals and vitamins.
However, ruminants are able to make use of them due to their rumen and to the cellulolytic microorganisms they host and which can degrade these materials.
a/ It is possible to improve the nutritional value of these feeds
either by supplying the microorganisms with the elements which are lacking in the roughage (nitrogen, minerals and vitamins) through adding a minimum “catalytic” supplement for which a concrete example comprises the “multinutrient” licking block, a supplement recommended for rangeland and for stubble grazing;
or by modifying the physical and chemical properties of the cell matter by treatment, which also assists the microorganisms to degrade the material.
The aim of this document is to demonstrate how this may be done and why and to see what one may expect in terms of animal production by adopting these techniques, together with estimating the chances for success in diffusing them amongst the small livestock farmers.
b/ Supplements
The minimum supplement should supply minerals, a little energy, and urea (a source of non-protein nitrogen which allows the microorganisms in the rumen to generate protein for the animal). The liquid mix of molasses, urea and minerals in the form of a solution may be utilized at a regional level or for cooperatives because it implies transport facilities, maintenance and storage of large quantities of the liquid molasses. Alternatively a simple and practical method developed some years ago comprises the multinutrient block, including molasses or not.
There is no fixed formula for making these blocks, rather a range of solutions which may be adapted to each specific situation. The principle consists in solidifying a mixture comprising molasses (30 to 50 %), urea (10 %) and minerals, a fibrous support structure (bran, dried leaves, bagasse, straw, chicken litter, …), together with a bonding agent (lime, cement and/or clay) so that a coherent, non-friable block is formed which may be licked by the animal in small amounts (400 to 800 g/day for cattle and 100 to 250 g/day for sheep and goats). Furthermore, it is also possible to make the blocks without including any molasses.
This is a technique of interest to small farmers who may make the blocks themselves due to the simplicity of the method. As these small farmers may have difficulty in obtaining regular supply of the necessary ingredients, it is often preferable to group together the block making activities within the village, through a cooperative or through an entrepreneur. This technique already forms part of the livestock development strategy in many developing countries.
c/ An alternative way for improving low quality forages is through treatment:
The two most commonly practised treatment methods are based on using ammonia or urea.
Treating with anhydrous ammonia consists in injecting ammonia under pressure, at a rate of 3 kg per 100 kg of straw with a minimum moisture content of 15 % into stacks of straw bales within a hermetic enclosure (the stack being covered with plastic sheeting). Treatment time depends on the ambient temperature (1 to 3 weeks for temperatures from 30 to 20°C, 4 to 8 weeks for 20 to 10°C). The technique is successfully practised in Western countries and around the Mediterranean (Tunisia, Egypt). However it presents the inconvenience that it requires the presence of an industry and distribution network for the ammonia supplies which rarely exist in developing countries. In addition, the technique cannot be readily accessed by the small farmer.
The alternative is to treat using urea which, in the presence of water, generates the ammonia for the treatment. There is no single technique which is applicable, rather a series of methods which should be adapted to local conditions by the extension agents who must thoroughly understand the principles involved. The parameters which have already been well proven comprise 5 kg of urea per 100 kg of dry forage made up into solution form with 50 litres of water (this amount can vary from 40 to 80 litres) and a treatment time of 2 to 5 weeks (for temperatures ranging from 30 to between 15 and 20°C). Hermetic sealing of the enclosure and cover is less critical than for the case of treatment with anhydrous ammonia and locally available materials may be used, the ammonia being released without creating a pressure.
Treatment efficiency improves at higher ambient temperatures. Thus it is specially indicated for use in tropical countries. This type of treatment is now practised in many developing countries where it forms part of the development strategy for livestock production.
These two treatment methods increase the crude protein content of the straw (which rises on average from 30 to 90 g/kg DM) and increase the energy value (which rises on average from 0.40 to 0.55 UFL/kg DM). Note that “UFL” represents the “Unit of Forage for MiLk” (in the French system).
d/ All the experiences recorded from one country or continent to another concerning the effects of the two techniques, using blocks or through urea treatment concur in their general opinion: farmers notice increased appetite, improved general condition and increased production for their animals.
Blocks are the supplement of choice for poor quality rangeland in the agro-pastoral zones. They will even allow modest growth rates, although few detailed figures are yet available.
Productivity of the animals may be further improved through urea treatment. It has been well proven that response in terms of animal production is better when one uses a given amount of urea for treatment than by simply adding the same amount to natural forage as a supplement.
When natural forage and crop residues are only available in limited quantities, they may be treated and used as a supplement for natural pasture grazed during the day.
When these are available in abundant quantities they can form the basic diet of the animals.
In both cases, treatment encourages the farmer to better manage the crop residues and natural forages which he has harvested.
The “response” to treatment in terms of animal production is more marked when the ration contains more of these forages. Those animals with only modest needs benefit most (these are the “target” animals).
Urea treatment allows one to economise on the use of supplements whilst still maintaining work efficiency and body condition of draft animals. It represents the best choice for the mixed farmer and the rice farmer. For equal amounts of supplement, it allows:
increasing daily growth rates by an average of 200 g/day when compared with feeding the supplement with non-treated straw,
increasing milk production between 1.0 and 2.5 litres/day (in addition to that suckled to the calf) when this is originally of some 2 to 8 litres/day at the start.
These increases are however, very variable. They depend on the initial forage quality and on the treatment itself. They also depend greatly on the quantity and nature of the supplements given.
In effect, in order to avoid any risk of losing the benefits of the treatment and “treating for nothing”, it is important to respect the rules for supplements, which are also valid for supplementing low quality forages which have not been treated:
quantities: the low quality forage should continue to make up the major portion of the total ration (at least half),
quality: it should be supplemented with feed which is rich in digestible fibre such as green forages, citrus pulp and beet pulp, …, feed supplying good quality crude protein (of low degradability) such as cereal byproducts, cake, leaves and pods from trees and waste and meal from meat and fish. These foods are the “strategic” supplements. Commercial concentrates are not generally appropriate as they are not conceived in this sense.
This notion of obtaining maximum advantage from treating becomes increasingly important in cases of high productivity levels of the animals. It is the case, for example, of systems which are closely associated with cereal production where the straw is indispensable as it constitutes the only “ballast” in the ration. For these systems, it is convenient only to give the treated straw to those animals which have modest needs, such as heifers at the end of their growth period and cows at the end of lactation, saving the best forages for the highly productive cattle.
From an economic point of view the chances for successful introduction of treatment techniques become greater as the role played by forage and crop residues in the production system becomes more important.
One may easily reduce treatment costs by using locally available raw materials and by interchanging services amongst farmers. When straw supplies are limited and, as sometimes happens, more expensive than concentrates (North Africa, the Near East), it is advisable to resort to a more detailed analysis of the production systems and the market for feed and animal products, before launching into a campaign to promote treatment.
e/ For facilitating adoption of these techniques by the small farmer, the extension programme must be accompanied by practical demonstrations and trials allowing collection of field data. These will effectively serve as solid complementary experiences to supplement data from the stations and will represent an essential tool for the extension agents and decision makers for their work in diffusing the techniques at farm level. It is also important to select “target” farmers who are sufficiently dynamic and influential amongst their neighbours so that they may play a role in the chain of transmission for diffusing the technique.
Certain support measures such as building up supply stocks of inputs (urea, minerals, …) and establishment of short term credit schemes for their purchase, will be indispensable for facilitating diffusion of the technique.
The introduction of techniques to improve the value of low quality forages constitutes an improvement to the feeding system. It should, however, remain complementary to more long term efforts for improving the forage system of the agricultural region when these are being undertaken and should not replace these efforts.
Finally, these techniques are elements which are favourable to the integration of livestock production into farming system with all the agronomic and social advantages, that this represents.
