Anthelmintics use for small ruminant production in The Gambia: a participatory and economic benefit-cost analysis

Christopher Ugochukwu Nwafor

International Trypanotolerance Centre,
PMB 14, Banjul, The Gambia
manchrizzo@hotmail.com

Abstract

 

Gastro-intestinal helminthes play important roles in reproductive and production loss in small ruminants. A strategic anthelmintic treatment increases productivity and financial profitability, as observed from a benefit-cost analysis carried out.

 

The results show that treatments using Fenbendazole (Panacur, Hoechst, 2.5%, 5mg / kg) between August and November resulted in a net gain of 16 dalasis and 14 dalasis on the cost of treatment for sheep and goats, respectively; and that small ruminant farmers in The Gambia will generate a minimum of 45% profit on the cost of treatment, while returns to capital invested is greater than the acceptable minimum rate of return.

Keywords: Anthelminthics, financial profitability, gastro-intestinal helminthes, productivity

Introduction

 

Sheep and goats play a major role in the rural economy of the Gambia, and small ruminant production as reported by Ankers et al (1998) is currently at the centre of most livestock improvement and intensification programmes in the country.

 

The Djallonke sheep and West African Dwarf (WAD) goats have been identified as the main breeds of small ruminant livestock in the Gambia. The WAD goat is described as an achondoplastic dwarf goat with a height ranging between 30 and 50 cm and weighs between 18 and 25 kg; while the Djallonke sheep is also a dwarf sheep with a height of 40 to 60 cm and weights between 20 and 35 kg depending on sex. Both breeds originate from the Fouta Djallon (Guinea, West Africa) and are found in many countries of the sub-humid zone of West Africa (Wilson 1991). They are able to survive and reproduce under stressful conditions based on heat tolerance, capacity to utilize low quality forage and resistance to certain diseases (Murray et al 1982; Mawuena 1986).

 

Traditional sheep and goat production in different parts of Africa is a very profitable enterprise, but returns are strongly determined by biological performance (Sumberg and Mack 1985; Upton 1985; Itty et al 1997; Panin and Mahabile 1997). In the tropics, gastro-intestinal nematodes in ruminants are often considered as a major constraint to optimal productive performance (Fabiyi 1987). Production losses and even death in small ruminants have been attributed to gastro-intestinal parasitism (Barger 1982; Beriajaya and Aron Batabura 1996; Tillard et al 1997).

 

The epidemiology of helminth infection in sheep and goats has been well studied in the Gambia (Greenwood and Mullineaux 1989; Fritsche et al 1993; Ankers et al 1994; Ndao et al 1995; Osaer et al 1999). An epidemiological study based on postmortem examinations carried out over a year by Fritsche et al (1993) showed that over 95% of sheep and goats are infected with gastro-intestinal nematodes. The strategies for the control of these nematodes, as observed by Ndao et al (1995), should be designed to prevent production-limiting parasitism at critical points in the epidemiological cycle. Treatments using Fenbendazole (Panacur, Hoechst) have shown significantly reduced mean nematode egg excretion per gramme faeces (EPG), as reported by Osaer et al (2000). The choice of Fenbendazole as anthelmintic (Ndao et al 1995) is based on its availability and broad spectrum activity against both mature and immature gastro-intestinal nematodes.

 

An anthelmintic intervention scheme based on two treatments has been tested and recommended (Ankers et al 1998). Fritsche at al (1993) reported that prevalence of the nematode adult population peaked during the rainy season lasting July till October. Ankers et al (1994) also observed that there was negligible helminth re-infestation during the dry season (November - May). The early dry season (November), has been suggested by Ndao et al (1995) as an ideal time for a strategic treatment in the Sudano-Guinean climate of West Africa. This suggestion is due to the absence of new infection from the pasture and because the whole parasite population lies within the host, and so would be entirely eliminated by the anthelmintic treatment.

 

The high incidence of gastro-intestinal infection by nematodes especially during the wet season has been attributed to the low input production systems widely practiced in the country; sheep and goats are crowded in open pens with little or no removal of droppings, non-existent veterinary attention or provision of drugs, cross infection and grazing in communal pastures. In the Gambia, the concept of a generalized chemoprophylactic anthelmintic flock treatment does not exist among livestock owners (Ankers et al 1998); only individually targeted animals will normally be dewormed.

 

The use of prophylactic anthelmintics, has been proffered as a possible intervention strategy in developing countries to reduce the impact of gastro-intestinal parasitism (Bullerdieck 1996). However, treatment is often expensive for the small-scale farmer and incorrect use often induces drug resistance. Waller (1997) suggests that grazing management techniques can support worm control programmes, and therefore reduce the reliance on anthelmintic treatments. Peacock (1998) observed that for the most economical use, these expensive drugs should be used in combination with improved management and at strategic intervals.

Effect of diseases on livestock

There is a high loss in productivity from diseases alone in ruminants, and this recurrent loss and hence reduction in profit is often due to parasitic infections; helminth infections particularly are a common and major problem in most parts of the tropics for small ruminant animals. Matika et al (2002) concluded that gastro-intestinal nematode parasitism imposes severe economic constraints on rangeland sheep and goat production in the tropics.

 

In a livestock system, animals make use of inputs (e.g. water, feed, drugs, labor, land, capital and management) to produce outputs (e.g. meat, milk, skin, manure and traction power etc). The efficiency with which inputs are converted into outputs, is referred to as productivity and defined as:

In a given production system, the effect of animal diseases is to decrease productivity by reducing the efficiency with which inputs are converted into outputs. Suffice to mention however, that for infectious and parasitic diseases in which the disease agent is in constant competition with its host for access to nutrient supplies, feed intake is often altered in the affected animals, digestion and nutrient absorption becomes difficult, and different physiological processes such as nutrient metabolism, respiration and excretion become modified (Tambi and Maina 1999).

 

According to Tambi and Maina (1999), the effect of diseases on a livestock system may either be direct (visible or invisible) or indirect in the form of additional cost or revenue foregone. These effects may not only alter the structure of a herd, but limit the capacity of the farmer to maintain and improve the herd; diminish access to better markets, lead to sub-optimal use of production technology and above all, cause increased use of additional resources to contain the disease.

Benefits from deworming

 

Though very few reports are available on the effects of prophylactic anthelmintic treatment in small ruminants kept under traditional extensive management in developing countries, the benefits accruing from the use of anthelmintics in small ruminant production have been widely reported (Fall et al 1982; Vassiliades 1984; Agyemang et al 1991, Osaer et al 2000; Ankers et al 1998).

 

A biannual anthelmintic treatment of naturally infected animals as reported by Vassiliades (1984) generated a 40% higher weight gain between 6 and 12 months and a decrease in mortality from 8% in control animals to 3% in treated animals. Overall improved productive performance of treated flocks compared to control groups, in various studies in The Gambia and elsewhere in West Africa have been confirmed (Rombaut and Van Vlaenderen 1976; Fall et al 1982; Sumberg and Mack 1985; Tuah and Baah 1985; Agyemang et al 1991; Faguère et al 1991).

 

Weight gain advantages of treated versus control sheep were observed by Goossens et al (1998), though the same effect was not observed for goats; and from previous epidemiological studies (Fritsche et al 1993), it can be assumed that treatment schemes considerably suppress worm burden in both sheep and goats. Kidding rates in treated goats were significantly higher than in the control group while in sheep, the same trend was observed but the difference was not significant. Osaer et al (2000) also report the positive effect of anthelmintic treatment on litter size and parturition intervals in both sheep and goats. Improved reproductive performance as a result of prophylactic anthelmintic treatment has also been reported in Djallonke ewes by Ankers et al (1998), with significantly increased lambing rates and litter size though the mortality and weight at 12 months were not significantly affected.

Economic returns from anthelmintics

 

A high rate of financial returns from the use of anthelmintics in small ruminant livestock production has been reported (Faguère et al 1991; Ankers et al 1998; Lesnoff et al 2000). Ankers et al (1998), report overall average return rate as high as 246% with variations in different areas while a return of 68% had been reported by Faugere et al (1991); and the latter recommends the scheme on the basis of these returns and the fact that 90% of farmers will make a profit by adopting the treatment scheme. Lesnoff et al (2000) using a steady-state approach of benefit-cost analysis with a periodic Leslie-matrix model observed a strong positive effect of deworming for both biological and financial productivity in sheep, and concluded that the marginal profit was higher than expenses. These findings support the use of helminthoses-prophylaxis scheme in Senegal, while similar conclusions were obtained (Ankers et al 1998) on a sheep population in The Gambia.

 

The role of gastrointestinal nematodes in small ruminant productivity, however, should be considered in combination with other disease and non-disease factors. The improvement resulting from anthelmintic treatment alone, as shown by Awa and Njoya (1997) suggests that this would give similar economic gains if other disease and non-disease factors are discounted.

 

Martrenchar et al (1997) reflected on the importance of cost effectiveness in disease control, and observed that anthelminthic treatment may not yield economic dividends despite the demonstration of the important role played by gastrointestinal helminthosis in production loss. These losses according to Tambi and Maina (1999) may be in the form of unrealized production potentials that are not clearly visible to farmers, who are averse to committing scarce resources into production. As a result of non-consideration of the socio-economic factors involved, Ott et al (1995) were critical of the standard benefit-cost analysis tool for economic appraisal.

 

While the experimental benefits from the use of anthelmintics are obvious, constraints from the farm perspective and the farm-household production objectives have overriding importance when a recommendation decision has to be made. Bjornsen and Gurung (2001) observed that suitable options need to be generated in close collaboration with farmers considering all dimensions of their livelihood. A change of strategy for the average farm household, involved in traditional extensive livestock production, has far greater implications than the derivative of financial net gain (the difference between the additional benefits and costs). In most cases, the identification, quantification and valuation of the resources used in traditional extensive production systems is practically difficult at best. Jordan (1986) postulates that an economic assessment of the effects of livestock diseases is often complicated by the existence of numerous variables some of which are unquantifiable, and agrees with the observation by Kamau et al (2000) that diseases have both direct and indirect impacts on the production system that are difficult to quantify in monetary terms.

 

Maximizing the physical production and income potential of small ruminants is often not a priority for most traditional farmers, who are generally satisfied with relatively low levels of productivity. It does not seem to be relevant therefore, to push the traditional system into its maximum capacity of production because most traditional farms are not profit maximizing oriented enterprises but rather follow a risk aversion strategy to maximize the farm household's utility objectives (Soedjana 1996). Uran et al (2001) observed that farmers are mainly focused on satisfying their immediate needs rather than making efforts to increase profit from one single enterprise.

 

Therefore research as a means to widen farmer's options, need to be highly participatory, action oriented and more importantly responsive to local needs and priorities (Bjornsen and Gurung 2001). The emphasis of research (Doran 2000) should shift away from technically based control operations to adaptive farming systems research, taking account of farmer circumstances and constraints. This also agrees with the conclusion by Agyemang et al (1997), that research should allow a greater emphasis on working more closely with farmers as this may be a more productive way of identifying viable, locally adaptable innovations that take into account the production resources and objectives of the various livestock owners; thereby contributing to increases in farm income and family welfare.

 

This study aimed to determine the economic merits of a proposed anthelmintic-prophylactic scheme, within the context of the farm-household production objectives; and to make a recommendation.

 

Materials and methods

 

Study site

 

The Central River Division (CRD), North Bank Division (NB), Upper and Lower River Divisions (URD, LRD) and rural villages in the Western Division (WD) of The Gambia were included in the study. The climate in the area is characterized by a short rainy season from June to October, with annual rainfalls ranging between 600 to 1200 mm. The dry season stretches from November to May, monthly average temperatures in June reaching a maximum of around 33.5 degrees centigrade. Much of the vegetation in The Gambia can be described as savannah woodland with grass and shrub understoreys like those of the Sudano-Guinean zone (Aubreville 1949; Dunsmore et al 1976).

Participatory learning

 

A participatory learning exercise was held in a village location. This was meant to explore and identify livestock diseases in the survey area; the importance of the disease condition;  and to elicit views about cause and preventive or treatment measures. The appraisal combined a livelihood analysis with disease identification and ranking exercise.

Farm-household / market survey

 

Two hundred and fifty farm households involved in small ruminant production all over the country were surveyed. Information related to production constraints, use of purchased inputs especially drugs, importance and availability (including affordability) of anthelmintics were obtained. The data obtained from the farm household survey were analyzed using the SPSS Version 10 system of statistical analysis. Data were also collected from weekly livestock markets, from October 2000 to August 2002. Price and live-weight of animals sold was recorded and compiled for use in the analysis. The market data was entered in an Access 2000 database and transferred into Excel for analysis.

Rate of return / Partial budget analysis

 

On station experimental results combined with economic data were used for a partial budget analysis to aid decision-making (Alimi and Manyong 2000). The general structure of the partial budget analysis is the net gain. The strategy is recommended for adoption if the sum of additional benefits is greater than the sum of additional costs (Tambi and Maina 1999). An existing model (see Table 1) was used to assess annual return rate to a prophylactic anthelmintic treatment in traditionally managed ruminants.

Results and discussion

 

Participatory Learning

 

The participatory learning exercise was held at Njolfen village in the Lower River Division. The villagers who participated in the exercise identified their various sources of income. Men identified farming, livestock keeping and trading as their primary sources of income while women identified gardening, lumbering (collecting fuel wood) and rope making as income sources. Three income sources (Table 2) were regarded as more important and benefits obtained from them were discussed.

The villagers recognized benefits obtained from keeping livestock, while the importance of other income sources was also stressed.  The participants then identified various factors constraining livestock production in the area; these constraints included theft, labor, feed, diseases and unavailability of clean water. In a subsequent ranking exercise; water availability, diseases and rampant theft emerged as major production constraints. Disease symptoms prevalent in the area were then identified and ranked with mortality as the main criteria; causes and curative measures for these symptoms were also mentioned (Table 3). Traditional practices are commonly applied to treat livestock of disease symptoms found in the area.
 

Diarrhoea was identified as the major cause of small ruminant mortality in the area, and the villagers were of the opinion that this was as a result of low quality feed and unhygienic drinking water sources in the village.

Farm household survey

 

A pre-structured questionnaire was administered to two hundred and fifty respondents, in twenty five villages across The Gambia. The villages include Baro-kunda, Basori, Batelling, Berending, Chamen, Demfai, Foday-kunda, Hela-kunda, Jahanka, Janneh-kunda, Kankuran, Kanuma, Kanumeh, Karantaba, Kataba, Kuli-kunda, Maka-bala-mana, Maka-farafenni, Missira-tenda, Munyagen, Njolfen, Nowleru, Nyamanari, Pateh-sam and Sotokoi. Farmers constituted 82.8% of the respondents while 3.6% were housewives, traders (2.4%) and other respondents in various occupation. The average age was 51.3 years; 62.4% of respondents had a non-formal (Koranic) education, 8% with a formal education while 29.6% had no education.

 

All respondents owned either sheep or goats including other livestock types. On a comparative basis, 37.2% of respondents had more than 10 small ruminant animals, 36.4% had less than 10 small ruminants while 26.4% kept less than 5 small ruminants. Goats are widely kept by more respondents than sheep and other livestock types, twenty three respondents exclusively kept goats while only four respondents had sheep only. Goats and cattle are kept by 7.6% of respondents compared to 2.4% for sheep and cattle. Respondents owning other livestock types (horses and donkey) including goats or sheep were 10.8% and 0.8% respectively.

 

Respondents in the survey identified diseases, as the main constraining factor in livestock production. This agrees with various conclusions from other studies in The Gambia that disease is a main constraining factor in livestock production (Osaer 1999; Nwafor 2004). Sixty five percent, twenty percent and fifteen percent of respondents identified disease, labour and nutrition as factors affecting livestock production. Family labour was used by 81.8% of respondents for care of sheep and goats, only 1.7% of respondents hired labour exclusively. Housing for animals is provided by 70% of respondents and ranges from a full sheltered hut to an open pen beside the compound. Supplementary feeding is given to the small ruminants by 68.4% of the respondents and consists mostly of hay, bran or cut and carry materials; only 1.8% provided feed concentrate. Ropes to tether the animals are purchased by more than ninety percent of respondents while 98% treat their small ruminant animals.

 

Drugs to treat sheep and goats were purchased by 81.6% of respondents, these drugs are purchased from drug sellers (comprising veterinary agents, livestock assistants and sundry traders) in the villages; only 10.8% of respondents purchase these drugs from conventional sources at the weekly markets. Most respondents (73.4%) consider these drugs expensive, and they opt for treating their livestock traditionally.  Also other reasons for treating animals traditionally include the unavailability of drugs when needed, and in some cases the effectiveness of the treatment administered. Forty -five respondents, 44 respondents and 34 respondents out of 150 responses; used traditional treatment for their livestock because of effectiveness, availability and affordability respectively. Other respondents used traditional methods because of a combination of these reasons, while for others it was due to customary practices and traditional beliefs.

 

Gastro-intestinal parasites have adverse effects on livestock productivity; and affect small ruminants in the survey area. Seventy percent of respondents agreed that worms affect their small ruminants, while 25.6% did not know if their animals are affected. Respondents saw the rainy season as the period of high worm prevalence. Various symptoms are seen by respondents as signs of worm infestation in small ruminants; these symptoms (see Table 4) include diarrhoea, weight loss, lack of appetite, rough coat etc.

 

 

Drugs are normally purchased by 45.2% of respondents to treat these signs, a combination of drugs and traditional treatment is also used while 26.4% do nothing when these symptoms manifest, as observed in Table 5 below.

 

Return rate and partial budget analysis

 

Reproductive parameters obtained from experimental flock populations by Ankers et al (1998) and Osaer et al (2000) for sheep and goats respectively were used. These parameters were updated with financial values from a current market survey (Table 6).

 

 

Sheep prices were 452 Dalasis and 512 Dalasis for average ewes and rams respectively; while an average doe and buck cost 452 and 432 Dalasis respectively (Table 7). On the average a deworming treatment cost 10 Dalasis irrespective of animal type.

 

 

The net gain is positive at 16.16 dalasis and 14.24 dalasis for sheep and goats respectively (Table 8) which implies that after every consideration and all things being equal, the incremental revenue is greater in real terms than the total treatment costs.

 

 

A change from zero treatment to a biannual treatment from the above scenario; gives an annual return rate of 179% and 169% for sheep and goats respectively, which is higher than the farmers acceptable minimum return rate of 120% (assuming the cost of capital to be 10% for a month). Farmers will therefore benefit from the treatment regime by 80% and 70% for sheep and goats.

 

Considering the inflationary trend and its effects on treatment cost, increases in the cost of the treatment scheme still gives a return rate that is financially rewarding (Table9) . Increases in drug prices are partially compensated by commensurate changes in the price of livestock. This is in agreement with the conclusion of Ankers et al (1998) that if the treatment price increases by 50%, the overall average return rate is still high.

 

 

An increase in the treatment cost in 2002 of more than 60% still generated a profit on the cost and positive return rate to intervention. There is a net gain over the total cost of treatment for sheep and goats and return rate greater than the acceptable minimum. The profit margin however is reduced to 50% and 45% for sheep and goats respectively, occasioned by the increased cost of treatment.

 

 

 

It therefore can be recommended that farmers in The Gambia use Fenbendazole (Panacur, Hoechst) as a biannual anthelmintic treatment for their sheep and goats, since there is a profit made from the cost of treatment and the annual rate of return to capital is greater than the acceptable minimum rate of return. An initial treatment during the rainy season in August is expected to decrease the pathogenic effects of the nematodes by removing the adult and larval populations under constant infection pressure. The second treatment given at the start of the dry season in November would eliminate all nematodes, including the hypobiotic larvae; with negligible re-infection risks.

 

Conclusion

• Gastrointestinal helminthoses cause reproductive and production losses in small ruminants.

  
  

• Strategic anthelmintic treatments increase animal productivity, as seen from the difference in performance between treated and control animals.

  
  

• The treatment also has improved financial implications for small ruminant farmers as they make a profit from the cost of treatment, and have a return rate that is higher than the acceptable minimum rate.

 

Acknowledgements

 

Special thanks to Dr.Steven Leak, Dethie Faye, Jacques Somda, Sofie Dhollander, Modu Gaye, Lamine Darboe, Lamine Fofana and Sidat Trawally; all staff of the International Trypanotolerance Centre (ITC), The Gambia. The efforts made by Dr. M. Mbake (ITC Bansang Station Manager) and Adeniyi Adediran (other matters) is acknowledged. The kind permission of the Director General (ITC) and project funding of the small ruminants research unit of ITC by the Belgian government made this study possible.

 

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