Extra Feeding or Trypanosomosis Control?

In some circumstances it is more beneficial to stop animals getting a disease like trypanosomosis.

For example only pregnant 'trypanosomosis free' females respond well to extra feeding given during the last part of their pregnancy resulting in bigger young. Trypanosome infected animals will not. Any monies that would have been spent on feeding infected animals should instead be used to protect them from getting trypanosomosis. A number of methods are available including using tsetse traps or treating sentinel stock, like large males, with insecticide so that the flies are killed as they land on animals to try to suck blood.

Nutritional supplementation does, however, have beneficial effects on litter size and lamb or kid growth rates. So feeding uninfected pregnant females during the last third of their pregnancy will generally increase birth weights of newborn animals and feeding them well in the first third of their lactation will mean plenty of milk for the young lamb or goat-kid so that they grow well. Supplementation of uninfected animals also tends to produce normal length rather than longer pregnancies.

Farmers will need help in using these ideas to improve how well they keep their animals so they can improve their productivity and eventually raise the levels of income from their flocks. This is because tsetse threats vary from area to area and individual livestock keeper's circumstances are often very different. Some will have more monies and others will be willing to take greater risks to improve their flock. Helping farmers to develop practical disease control or sensible feeding systems will need support and advise from extension staff who understand the options. This needs to be done early so that benefits are visible and confidence is gained. This will encourage farmers to carry through ideas where real benefits might take several months or even years to achieve. There is a role here for NGOs, vets and government or commercial animal health advisers to guide farmers. Farmers need practical help in identifying what types of feed to give their flock. Costs of purchased feed vary, as does its quality over time. Protein levels of different feeds, concentrate rations, forage crops or by-products vary and will all affect growth.

There is a cost either in time or cash to feeding livestock. If feed can be made available to animals only when the benefits are maximized it will give poor farmers the best return for limited time, money and resources. Extra feeding should be avoided if the benefits are likely to be limited or poor, such as feeding animals before they get pregnant.

There is some risk involved in both taking measures to prevent animals getting trypanosomosis and in additional feeding. The risk is related only to the costs of such measures and neither extra feeding nor disease control should do any actual damage to animals themselves. The losses would relate to losses to the livelihood of a farmer by using his limited financial resources badly. This could obviously be very serious in some individual situations.

There may be risks of negative environmental impacts from the use of chemical methods of tsetse control.

The information above encourages farmers to use their limited resources to try to prevent animals being bitten by tsetse flies and thus getting trypanosomosis. The alternative is to use strategic feeding of livestock in combination with tsetse control measures. Farmers' ability to undertake both disease control and good feeding will relate to how much money they can afford to spend.

Disease control measures may not suit all farmers for some of the most successful tsetse control programmes are run by communities rather than individuals and success is directly related to good community collaboration that may not exist. Also community programmes do not always benefit everybody equally. A particular farmer may feel that his or her flock would benefit more from using what little resources exist to improving the family livestock rather than contributing to reducing tsetse fly populations that improves a village livestock population.

Establishing that nutritional supplementation is actually less important during the breeding period than trypanosome control measures will assist the better targeting of limited financial resources on reducing the impact of the disease on rural livelihoods. This information could allow policy makers to identify strategies for improving the performance of small ruminants in the vast areas of Africa that are trypanosome-endemic.

The cost of therapeutic drugs for trypanasomosis can be relatively high. Therefore, access to low-cost strategies, using locally available resources - in this case feeds - to counter the impact of pathogens on animal performance, has an impact on the livelihoods of the poor reaching far beyond the supply of animal products for household consumption.

Identifying if benefits accrue from nutritional supplementation during late pregnancy and early lactation will also facilitate more effective allocation of scarce feed resources at the farm level.

More information on controlling tsetse and feeding small stock is to be found in the publications produced by the scientists involved in this DFID funded research, including:

Osaer, S., Goosens, B., Jeffcoate, I.A., Jaitner, J., Kora, S. and Holmes, P.H. (1998) Effects of Trypanosoma congolense infection and nutritional supplements on establishment and outcome of pregnancy in trypano-tolerant Djallonke ewes. Animal Reproduction Science, 51: 97-109	[Abstract]
Improving the Performance of Trypanosome- Infected Smallstock

This project capitalized on long- standing links between the University of Glasgow and the International Trypanotolerance Centre (ITC) in The Gambia. They would be interested in hearing from NGO's and others interested in developmental problems, such as the poor performance of livestock under a disease challenge that seriously hinders the livelihoods of rural families in Africa.

I.A. Jeffcoate, School of Veterinary Science, University of Glasgow, UK;
B. Goosens, S. Osaer, International Trypanotolerance Centre (ITC), Banjul, The Gambia;
P. Humblot, UNCEIA Services Techniques, Maisons-Alfort, France

This information is part of a series on small stock that cover disease-nutrition interactions.