The results from the study show that cattle was a major livestock species reared followed by indigenous chicken, goats and sheep. This finding broadly supports the work of other studies that highlighted the role of cattle and other livestock species in supporting pastoralist livelihoods [20, 21, 22]. Cattle in pastoral and agro pastoral communities plays multifunctional role in providing both market and non-market benefits. The later include financing and insurance functions which define the competitiveness of cattle rearing in pastoral and agro pastoral communities [23]. Cattle and other types of livestock in pastoralist and agro pastoral households support an important role in coping with shocks, accumulating wealth and acting as a bank in the absence of commercial financial institutions and formal markets. [24] .
In terms of cattle herd structure, adult cattle were majority in household herds. Heifers, female calves and weaners followed in that order (Table 1). The results show that more female cattle were kept compared to male calves and bulls. The findings might indicate that pastoralists keep more female cattle because of their ability to produce milk and for herd growth. This finding is consistent with another study that of [25] where female cattle of reproductive age constituted more than 50% of all livestock species. This is contrary in areas where male cattle are used for traction.
The overall prevalence and mortality rate of bovine trypanosomosis was 33.4% and 7.8% respectively (Table 3). These results are far below those found in Metekel Zone North West Ethiopia which reported prevalence of 12.1% and mortality rate of 4.4% [26]. These differences in prevalence and mortality rates could be caused by variations in vegetation types and the seasons when the studies were conducted. The type of vegetation and season are known to determine the tsetse population and consequently the prevalence and mortality rates [27–29]. In addition, another plausible reason for the difference could be attributed to the breed of cattle kept. In areas where crossbred cattle are kept compared to indigenous breeds it’s likely to find higher prevalence and mortality rates. From this study the highest mortality rate was reported in steer category of cattle while the highest morbidity rates were observed among dry cattle. A possible explanation for this might be that larger animals were more attractive to tsetse flies compared to smaller animals. Large cattle produce more odor plumes that attract tsetse than calves. This was further supported in previous studies [2] and [30].
The control measures of trypanosomosis mainly involved use of trypanocidal drugs with isometamidium chloride (Samorin®) as the main drug of choice. Although the drug is more expensive compared to other trypanocidal drugs on the market, farmers revealed that it has both curative and protective effects on the animals. The farmers revelations were in support with earlier study [31] where it was reported that Isometamidium chloride mode of action was both therapeutic and prophylactic. From our analysis, prophylaxis treatment three times a year would protect cattle herds costing USD 110 or Ug.shs 384,000 annually per household. This would drastically reduce the high mortality rate loss caused by trypanosomosis (Table 5) thereby increasing profit margins of cattle keeping in the area. This is in agreement with studies
done elsewhere [32, 33] where they found higher returns on investment when farmers used trypanocide prophylaxis to protect their cattle against trypanosomosis.
In addition farmers in this area did not spray their cattle against tsetse flies using insecticides. In other areas infested with tsetse flies [13, 8)] farmers have used dual purpose insecticide like deltamethrin to control both ticks and tsetse. Spraying the entire animal’s body uses large amounts of the insecticide wash which is costly and leads to environmental contamination. The Restricted Insecticide Application protocol (RAP) is now being advocated for [33]. RAP involves application of insecticide to tsetse predilection sites of the animal (bellies, fore and hind legs) and in the ears. These are also the predilection site of Rhipicephalus Appendiculatus. The anticipated benefits of RAP compared to full body spraying include reduced over dependence on trypanicidal drugs, lowered risk of drug resistance and cost of tsetse and tick born disease control [34].
From this study (Table 4) it was shown that dry cattle and steers were salvage sold at a price less than market value. Salvage sales were done by farmers to avoid complete loss as a result of death. Animals that were salvage sold are ones that failed to respond to treatment and continue deteriorating in their health till the farmer decides to dispose them before dying. As a result, farmers made losses depending on the state of the animals and the salvage price offered. It was found that farmers lost 56.1% as their income due to salvage sales. This was far less compared to percentage loss of 83% for bulls and 88% for cows caused by foot and mouth disease outbreak in Isingiro [35].
The mean annual economic cost per household due to trypanosomosis was found to be USD 693 of which 83% and 9% were due to mortality and milk loss respectively (Table 5). The mortality loss was equivalent to USD 588 which was higher than USD 244 reported in Metekel zone Ethiopia [33] and USD 200 in Baro Akobo and Gojeb river basins Ethiopia [36]. There are several possible explanation for this result. One possible explanation might be that the mortality loss is contributed by other diseases that can present signs similar to those of trypanosomosis. However, in this area there was lack of laboratory services where farmers and field veterinarians can diagnose blood samples to confirm presence of trypanosomes before treatment. This finding is in agreement with an earlier study [37] which reported that the use of veterinary diagnostic laboratory in Uganda was poor. Also there were no veterinary diagnostic services found in the area. The farmers were treating cattle themselves failing to administer right curative trypanocides at the right dose. There is therefore a need to provide a trypanosomosis diagnostic and veterinary services for sick cattle. Also there are substandard and fake trypanocidal drugs on the market which may contribute to treatment failure.
The drive by most farmers to improve genetically their herds through crossbreeding may also contribute to the high mortality in crossbred animals compared to local breeds as previously reported by [38, 2].
When farmers invest in preventive treatment regime of 10 animals per 1 sachet of Samorin® at an interval of every 3 months per year, the annual cost of treatment per household would be USD 110. The return on investment in treatment would be USD 540. This could be saved annually making cattle keeping enterprise profitable venture in this area. This therefore means that prophylactic treatment regime should be adopted in this area.
Milk loss of USD 63.4 annually per household due to trypanosomosis is the second largest contribution to the total economic cost. The loss in milk was mainly through death of lactating cows, abortions of dry cows and decreased milk yield in sick cattle. Milk is an important component of the communities’ diet and milk loss undermines the daily household incomes. Milk which was not directly consumed was locally processed into other value added dairy products which could be sold locally. With increasing population in Buliisa district and the oil discovery within the district the demand for milk is growing hence becoming a major source of household income.
It is surprising that the percentage contribution of treatment and bush clearing is less than 1% (Table 5) yet more than 50% of the households reported their animals were infected with trypanosomosis the previous year. The small contribution of treatment cost to total economic cost of trypanosomosis may be contributing to high mortality loss observed in cattle due to trypanosomosis. Another plausible explanation might be that farmers use ethno veterinary treatment in managing trypanosomosis which was not recorded in this study. In addition most farmers keep local breeds of cattle which are thought to be more trypanotolerant and therefore are reluctant to invest in treatment costs compared to farmers with crossbreed animals which are have shown to be trypanosusceptible.
In this study bush clearing and use of traps were not used by most farmers. A possible explanation for the low practice of bush clearing might be that land is communally owned and communities were not motivated to invest in it despite knowing that bushes were breeding habitats for tsetse. Bush of different types provide good breeding environment for different tsetse species. The Glossina palpalis and G fusca tsetse species thrive well in woody vegetation while the G. moristan species survive best in savannah woodland. Furthermore, indiscriminate bush clearing as an approach to control tsetse population can lead to negative impact on biodiversity loss and the approach is not ecologically and politically acceptable. However there has been modification developed [39, 40] which include removal of vegetation at ground level without removing high trees (discriminative partial bush clearing) or cutting only some of the trees or shrubs species (partial selective bush clearing) which are effective in reducing the tsetse populations. Traps were not being deployed as tsetse control measure in study area. The probable reason why traps are not popular among the farmers might be lack of their promotion as an important tool to monitor spatial and temporal changes in the tsetse population and non-functional livestock extension, entomology and community tsetse control intervention programs [41]. There are several limitations to the wider use of traps which could be non-community involvement in their deployment, supervision and management, high cost and high rate of theft and vandalism.
Relatedly bush or vegetation influences the efficiency of use of insecticide impregnated traps and targets. The effectiveness of traps and targets in controlling tsetse flies can be hampered by vegetation regrowth and encroachment [42] who found a significant decrease in tsetse catches when the traps were obscured by 80%.