Protein bank for pig production in Colombia

The tree foliage allows saving the cost of raising a pig by 15%, i.e., $19 / pig. On average, a smallholder raises 8 pigs, which gives an extra income of $216 per year.

Feeding pigs with tree leaves? How odd it sounds for many of us! Not for the smallholders living on the Andean foothills along the Cauca river valley in Colombia. The farmers here use the leaves of shrub trees, such as mulberry (Morus alba), taro (Xanthosoma saggitifolium), Trichanthera (Figure 1) or Erythrina, to feed their pigs and the pigs like them!.

It all started some years ago when the world coffee price dropped and remained low for a longer period than usual. Many producers got desperate. They sold their farms and went to cities. Others remained and tried other agriculture production systems.

Trichanthera trees used as living fences We had no choice, says Antonio, a former coffee producer. The cost of producing coffee had been higher than the selling price for three consecutive years. Antonio and many other small farmers started uprooting the coffee trees and replaced them by fruit trees, cassava or corn. However, the fruits were attacked by bugs and diseases and the cash crops could not be grown on the steep slopes of the Andean foothills. Eventually, the fields ended as a wasteland.

Some farmers contemplated the possibility of raising pigs that do not require much space, breed easily and eat almost anything. Also, the price of pork meat is twice that of beef. However, producing pigs by feeding them commercial concentrate was costly, at around US$129 to get a pig to a bodyweight of 100 kg. Farmers obviously could not invest this amount since this is the average monthly income of a small farmer.

The farmers then came into contact with the Centro para Investigacion en Sistemas Sostenibles de Produccion Agropecuaria (CIPAV) Foundation, a non-governmental organization, specialising in the development of sustainable agricultural production systems. One of these systems aimed at producing tree leaves for use as pig feeds (Figure 2). The rationale behind the use of tree leaves as pig feeds was that only ligneous plant species are adapted to the steep slopes of the Andes. Their interest lies, of course, in erosion prevention, says Enrique Murgueitio, Director of the Foundation. In addition, they also contribute to water preservation and soil fertility and their foliage ideally balances the ingredients used by the farmers such as cassava or sugarcane molasses for feeding to pigs. Cassava and sugarcane molasses are, indeed, good sources of energy, whereas tree leaves provide proteins and minerals required by the animal.

Pigs consuming tree leaves At that time, the use of these unconventional feeds in pig nutrition was empirical and not based on data on composition and nutritional value. This lack of knowledge affected the efficiency of the systems. In order to generate this information, the International Atomic Energy Agency (IAEA), financed a TC Project (COL/5/020), developed jointly by the CIPAV Foundation and the National University of Colombia. Nuclear techniques were used to evaluate the protein quality of the forages. Differentiation was made between dietary proteins and those coming from the secretions within the small intestine of the pigs, by means of the isotope dilution technique using nitrogen-15 (15N). The IAEA provided expert services on the use of the nuclear techniques for feed evaluation; trained laboratory personnel on feed analysis; established a state-of-the-art animal nutrition laboratory and provided funds for establishing pilot farms and for organising technology demonstrations and training workshops. The use of nuclear techniques provided unique data on the true digestibility of proteins (Table 1). The Belgian Ministry for Development Cooperation also supported this project by providing funds for surveys as well as for experimentation on foliage composition; voluntary feed intake; nutritional value in pigs; pig growth in pilot-farms (Figure 3) and for disseminating the information to scientific community.

Table 1. Composition and nutritional value of some tree leaves (g/kg dry matter)

  Trichanthera1 Mulberry2 Taro3
Ash 155 118 128
Crude protein 210 182 235
Digestible protein 84 69 82
Total fibre 400 248 275
Calcium 60 22 22
Digestible energy (kcal/kg DM)
- in growing pigs 1700 1800 2100
- in sows 1900 2700 2700

1, Trichanthera gigantea; 2, Morus alba; 3, Xanthosoma saggitifolium

The project helped to define the amount of foliage that pigs were able to ingest. Tree leaves of any of the three species mentioned in Table 1 can account for up to 30% of a sow's diet. It also showed that leaf proteins are well balanced in amino acids but are poorly digested (<50%). So proteins are not deficient in any essential amino acid, such as lysine, tryptophan or methionine but their supply to the animals body is not very high. One of the most interesting observations was that tree leaves are good sources of minerals, especially calcium. Minerals are generally limited in tropical animal feeding and deficiencies affect the performance of animals, especially reproduction. This problem, to a great extent, is overcome by using tree leaves. Small farmers confirmed that sows fed with tree leaves had better body condition; grew at a higher rate; come into oestrus more easily and had vigorous piglets. One of the trees, Trichanthera gigantea, was particularly attractive in this respect. It contains approximately 6 % calcium, on a dry basis and with only 0.5 kg dry leaves per day, it was possible to meet the high calcium requirements of lactating sows!

Pig weight registration during a growth experiment in a pilot-farm Many farmers who visited the pilot-farms established through the project, showed interest in establishing pig production systems based on feeding tree leaves and other locally available and reasonably priced resources. Initially, they were interested in producing their own feeds using ingredients available locally so as to reduce the use of commercial concentrated feed. Growing pigs fed with 1.4 kg/day of commercial feed, 2 kg of whole sugarcane and 3 kg fresh tree foliage, produced an average daily gain of 500 g per day. The added tree foliage allows a reduction of 30 kg in commercial feed during the whole growth period, without sacrificing the growth rate achieved on feeding all-concentrate diet.

This saving of 30 kg of commercial feed reduces the cost of raising a pig by 15 %, i.e., $19 / pig. The cost for raising a pig to 100 kg body weight using concentrate feed is $129 and for using tree foliage is $110. With a selling price of 100 kg pig at only $137, the profit is $8 with the total concentrate-based diet and $27 with the tree foliage containing diet. It is therefore worth raising pigs by using tree leaves in the diets. On average, a smallholder raises 8 pigs, which gives an extra income of $216 per year. The farmers were also attracted by the stability offered by the system since once the trees have been grown, the leaves can be harvested at any time. The trees are usually used in rotation where branches of some trees are cut every day. When the branches from all trees have been cut, the first trees used have re-grown and are ready for another cutting. This system of using tree foliage is called protein bank because leaves are rich in protein and are available all the year round and can be harvested at any time (Figure 4). The recycling of pig manure on the fields also increases productivity significantly. The trees are generally resistant to diseases and an association of different species further reduces the occurrence of diseases.

Protein-bank: various tree species grown in association The main challenge is to establish the trees for use as the protein bank. The trees reproduce vegetatively and the stems with buds are not always available. A further constraint for the smallholder farmers is the lack of access to capital as micro-credits systems are not available in Colombia. These constraints were identified through the results of a large survey under the IAEAs TC Project by the National University, in which more than 300 farmers from the Cauca river valley were interviewed. Land availability did not seem to be a limiting factor. The survey revealed that up to 20 % of farm areas was under-used or not used at all, despite the small size of the farms (45 ha on average, ranging from 0.3 to 10 ha). If farmers had better access to credit they could use their farms more productively, namely by growing shrub trees in the 'free' areas on their farm! To try and overcome financial constraints farmers unite their efforts to prepare the soil and share the equipment needed for establishment of the protein bank.

None of the farmers who adopted the systems (currently they are over 200 farmers in the region), regret their decision. Apart from the financial advantage provided by saving of the concentrates in the animal diet, the farmers see other advantages such as improvement in soil fertility and better management of water. All this makes the system more sustainable. Looking at the success of these farmers, more and more farmers are now participating in the training workshops organised by the CIPAV. This also includes 5 farmers from neighbouring countries such as Venezuela, Ecuador, Nicaragua and Panama.

Happy Alberio!! a case study

A happy farmer With less than 1 ha of land, Alberio Carmona had no other choice but to work for others as a farm labourer. His land produced only vegetables and he got eggs from his poultry, which was just enough for meeting the requirements of his family. His salary, therefore, was just sufficient for subsistence and some extra cash would be most welcome to assure a possible visit to the doctor or to help educate his children.

When he heard about the CIPAV-IAEA project and the possibilities of producing pigs with feedstuffs produced at the farm, Alberio was tempted to try. He participated in a short training course organised by the project team in a pilot-farm and then made an attempt to raise pigs. The most difficult was the installation of the trees, he says. Protein banks are not for lazybones! Fortunately, he was able to rent a bush cutter and he also received help and guidance from his neighbours. Once the trees had grown, he started rearing a sow and weaned nine piglets in two months. All the piglets were sold and with the money received, he bought concentrates. After 6 months, the sow gave birth to second set of piglets. This time, he kept half the piglets and raised them with the concentrates he had bought and the tree leaves from his protein bank. This provided him an addition $108 per year, i.e. equivalent to one month's salary. With time, he hopes to fatten up the whole litter. What makes him happier is that the education of the kids is now more assured and that some pesos are kept under the mattress for emergencies, so he feels much less anxious when thinking about the future.