An innovative technique for storing and feeding sweet potato to livestock, developed by NARI’s Livestock Programme, stands to improve small-scale pig farming in PNG. The technology, ensiling, offers pig farmers, especially women, not only nutritious and palatable feed for improved productivity but also enhances cost effective use of available food resources and reduces labour intensity in feed preparation.
Pig keeping is very popular in PNG where pigs are highly valued, particularly in the Highlands. Pig farming at smallholder level was reported to be 27,000 tonnes of pork meat annually, far above the output of commercial piggeries at 1,000 tonnes. A conservative estimate of the total value of smallholder pork production is K190,000. But there are constraints and development obstacles that need to be addressed so that farmers in rural locations can take part in the commercial production of pigs.
The vast majority of pigs are kept by subsistence village farmers under traditional farming. Growing and preparing pig feed is a burden often carried out by women, an additional responsibility to their regular field and household chores. Long term storage of livestock feed after harvest is not often practised by farmers. Food gardens are grown all year round and harvests are instantly used by people as food and pig feeds.
Commercial feed available as pellets is a balanced diet, easy to store and use. However, it is very expensive for small growers with limited budgets. Sweet potato is the most popular pig feed usually as a by-product from human consumption. Ensiling is a method of processing fresh/dried forage to enable its preservation and storage over many months.Ensiled forage, called silage, provides a very nutritious and highly palatable meal for animals such as cattle, sheep, goats and pigs.
Silage is made from grains, pastures, legumes or tubers like sweet potato and cassava. When forage is ensiled, it undergoes a chemical reaction known as anaerobic fermentation. Ensiling sweet potato involves four major actions:
- Harvesting forage at the right maturity;
- Cutting or milling forage into an appropriate length;
- Filling, packing and sealing in an airtight container; and
- Using additives to ensure correct fermentation.
Making and feeding silage is a common practice in many countries. Conserving feed helps to effectively tackle seasonal crop or climate variations, market economics and production problems. The sweet potato-silage system can be seen as an improvement to PNG’s traditional sweet potato-pig system. Sweet potato silage improves on traditional pig feeding where ensiling enables the forage produced during lush seasons to be stored for use during the lean times. Silage also offers the advantages of having easily digestible nutrients, lessening the daily drudgery and labour hardships (especially for women) as well as having the potential for reducing running costs involved in keeping pigs under smallholder or village settings.
In addition, sweet potato silage is an excellent source of energy for growing crossbred exotic pigs when compared to a traditional diet of boiled tubers and fresh vine and a commercially formulated standard grower pig diet. Research has shown that when properly managed, locally-bred growing pigs can perform well when fed on mixed sweet potato silage and commercial feeds (see figure). Some farmers also use farm by-products like fish, copra meal and palm oil kernel or refuse material from biscuit and noodle manufacturers. With the development of agro-industries, supply of some of these by-products will increase and can provide valuable feed for livestock. However, these alternate feed sources are far off from rural dwellings where smallholder pig farming is taken up without appropriate storage facilities. Unfortunately, while there is demand for pork, what is lacking are good roads, transport services, abattoirs, appropriate freezer facilities, meat inspection and veterinary services.
What is much needed is the development of supply chains (not just roads) that enable protein feeds to be readily available to smallholder livestock farmers at local (didiman) stores and for livestock (and crop produce) to be delivered to food processing, storage and market outlets. This can lead to agri-business opportunities and real economic prosperity in rural communities. Another plausible benefit for smallholder farmers is the low opportunity cost of labour in rural locations which makes pig farming using adapted agricultural technologies, such as ensiling, relevant in creating gainful employment and enhancing rural livelihoods. It is good for pigs and good for people too!
Particular needs that will enable livestock production to be more effective and efficient are simple tools and machines (appropriate technology) for processing forage, with available parts and maintenance services (eg PSS Limited), access to credit facilities for start up capital (eg NADP funds) and extension services that link farmers and facilitate the communication of agriculture information and advice. Sweet potato silage is a technology option that has the potential to improve pig farming in PNG through more cost effective use of available feed resources and by developing the ability to conserve feed in a nutritious manner over a longer time. The process of adopting these innovations will be challenging but the proven benefits point towards a brighter future for smallholder farming.