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| The Context |
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Fascioliasis, or Fasciolosis, caused by liver fluke parasites is a major threat to livestock kept by resource poor farmers and causes serious losses in cattle, buffalo, sheep and goats. Fasciolosis exerts a serious effect on body weight, milk yield and
composition, as well as on fertility in cattle sheep, goats and buffaloes. For example in
Nepal estimated meat loss, through reduced body weight, in buffaloes is 14.5 million
US$ annually (at 18,500 metric tonnes c.20% of production) and in goats, (at 4,220
metric tonnes c.12% of production).
Here the climate and farming practices favour the survival of snails that are intermediate hosts in the life cycle of the parasite or trematodes. The parasites responsible for fasciolosis are mainly Fasciola gigantica and F. hepatica (at higher altitudes) although the latter parasite is more common in temperate countries like the UK. Animals pick up the parasite when they come into contact with snails whilst drinking in streams and pools.
Flukes damage an animal's liver and can cause death or serious production losses through 'wasting' from loss of red blood cell capacity. Effects range from poor weight gain and lower carcass quality to high death rates especially in young stock. The disease effects are magnified by poor nutrition. Drugs are effective if well targeted but for poor resource farmers they are often too expensive and sometimes not available. |
| Methods |
The solution - Trees leaves are better than drugs!
It is important to recognize that better feeding of livestock covers both the quality or type of food, and quantity of food.
Scientists in Edinburgh and Nepal have found that diets with different protein and nitrogen contents have different effects on an animal's ability to withstand and to recover from infection with Fasciola gigantica.
They recommended that farmers should aim to feed a diet containing up to 14% protein. To help achieve this level of protein the basic diet should be supplemented with either tree fodder or feed concentrate or urea/molasses blocks. |
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Most stock in Nepal, such as goats or buffalo, are kept on a very low protein diet obtained from relatively poor quality grazing. Additional feeding of high quality protein feeds such as from tree leaves or from cheaply purchased urea/molasses feed blocks is one possible way to boost the protein level. Harvesting tree fodder has obvious cost advantages to a farmer, as it is often free to collect, as long as it does not promote environmental degradation through trees being cut down or killed.
Tree fodder has significant potential as a feed supplement:
- it is nutritious
- can be grown and harvested on the farm
- the tannins in leaves reduce the severity of fasciolosis by stopping flukes establishing themselves in the liver.
Regular feeding with tree fodder will also often be better and more cost effective than drug treatment and there is now evidence that some leaves may contain positive natural chemicals that help to suppress the parasites. In the Nepalese context, tree fodder is both available and affordable to farmers and therefore would be the technology of choice to combat fasciolosis in comparison to broad-spectrum anthelmintics, concentrate feed and/or urea molasses blocks. |
| Support and Resources Required |
This approach to combating fasciolosis is completely sustainable if a balance is kept between cutting fodder from trees to feed to animals, environmental requirements, and the capacity of the trees to regenerate and/or withstand the cutting. It is most important that the cutting or harvesting of tree fodder does not kill the trees. This means:
- starting with good initial advice and guidance from NGOs or extension workers,
- and careful monitoring of the environment.
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| Costs and Benefits |
Investment in feeding to improve animal health and combat fasciolosis in Nepal has been found to be cost effective.
Feeding purchased or home grown concentrated foods will generally give the better results than feeding tree fodder and sometimes even better than drug treatment but not all farmers can afford these feeds or drugs. Those that can will have animals with more valuable carcasses as they contain a higher percentage of meat that is acceptable to eat. This means more of the carcass can be sold at better quality and at a higher sale price. However, feeding cheap and available tree fodder is a very valuable option for poorer farmers who cannot afford drugs or concentrates.
The costs of not treating animals against or feeding them greater amounts of protein to combat fasciolosis ranges from poor weight gain and lower carcass quality to high death rates.
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| Risks |
If the farmer can source free tree fodder for his livestock then the risks involved in feeding leaves relate only to the cost of his labour and the potential damage to trees, and to the environment. Farmers must harvest the tree fodder in a way that allows the tree to recover whilst yielding enough to feed his or her animals. This will very likely involve harvesting different trees at different times of the season or year, or just taking a small, sustainable quantity from each tree on a regular basis.
Feeding too much concentrate protein (over 19% of total ration) is also a waste and is as bad as feeding too little (below 7%) as it causes relatively poor growth. The former is a very costly exercise if no extra produce is achieved! |
| Alternatives |
Where affordable, the use of anthelmintic drugs strategically or symptomatically is still a recommended option for an integrated fasciolosis control programme.
Another pragmatic alternative includes feeding the top halves of rice straw (which is non-fluke infective) as fodder immediately after harvest, followed later by the bottom parts which are likely to cause more infections.
Treating animals with drugs is still recommended in Nepal as part of a strategic and systematic approach to controlling fasciolosis but as previously stated the cost of any drug might be beyond the financial capacity of poorer farmers. |
| Impacts |
In the short term, adoption of the above recommendations would be of immediate and practical help to Nepalese farmers. They need to be incorporated into the agricultural information delivered to farmers in Nepal by government departments, demonstration farms, schools, vet services and the media. Similar results and recommendations are also likely to be relevant in other geographic areas. |
| Policy Implications |
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| References and Further Reading |
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| Related Research Projects |
This information is part of a series on small stock that cover disease-nutrition interactions.
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Controlling trypanosomosis in Sheep & Goats is more important than extra feeding |
| R6342 |
Best Feeding Practices to help animals fight Trypanosomosis |
| R6358 |
The Decision Tree that Helps counter the threat of Trypanosomosis |
| R6561 |
Helping lambs to control stomach worms before they get sick |
| R6608 |
Feeding Tree Fodder to beat liver Fluke |
| R7424 |
Farmers can use Tannins to kill parasitic worms |
| R8151 |
Sensible use of drugs and feeding to stop roundworms killing sheep & goat |
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