The use of chemoprophylaxis in East African Zebu village cattle exposed to trypanosomiasis in Muhaka, Kenya

A study conducted to assess the efficacy of chemoprophylaxis for the improvement of the health and productivity of East African Zebu village cattle exposed to trypanosomiasis. Examines the cost-effectiveness of the treatment. Includes data on calf pre-weaning health and weight traits, weight traits of calves from 12-18 months of age, calf post-weaning health and weight traits, and breeding cow health and production traits - for the non-prophylactic and prophylactic groups

The trypanotolerance network. 2. A study on health and productivity of N'Dama, Nguni and their crosses under quantified levels of tsetse challenge in Gabon. 2.1. - Tsetse survey

Examines the proboscides, midguts and salivary glands of live tsetse species for trypanosomes trapped at forest edges, inforest close to watercourses and at the boundaries of savanna and pastures in Gabon to confirm the existence of a considerable trypanosomiasis risk due to the high infection rate encountered in cattl

Systematic epidemiological studies to identify and resolve health constraints to smallholder dairy production in coastal lowland Kenya

Since 1989, a step-wise series of farming systems surveys and epidemiological studies have been carried out in coastal Kenya to identify and resolve major disease constraints affecting smallholder dairy production. This paper describes the sequential studies and reports on the significance of, and intervention against, East Coast fever (ECF). The study was carried out in Kaloleni Division which has three agro-ecological zones (AEZ). In the point-prevalence study, exposure to ECF 20, measured by detection of antibodies to T. Parva schizonts in the indirect fluorescent antibody test, was influenced by AEZ and grazing system. In the wetter areas T. Parva antibody prevalence in free grazing cattle was higher than in drier area while in the wetter zero-grazed dairy cattle had a lower prevalence than those in the free-grazing system

Use of the isometamidium Elisa to measure serum concentrations of the drug in Jersey dairy cattle in Kenya

Isometamidium chloride is the most important chemoprophylactic agent used in the control of African bovine trypanosomiasis, although breakdowns in prophylaxis have been observed in the field. It is not usually apparent whether these breakdowns are due to inadequate drug dosage regimens, or to the Development of drug-resistance in trypanosomes. A recently developed enzyme-linked immunosorbent assay (ELISA) for the detection of isometamidium provides a means of resolving this question in field situations. This was tested using sera from Jersey cattle under isometamidium prophylaxis (0.5 mgkg-1 body weight by intramuscular injection at three-monthly intervals), which were exposed to natural tsetse challenge in coastal Kenya. Although isometamidium could be quantified in the sera of the treated cattle, the incidence of trypanosomiasis, determined by the presence of parasites in the buffy coat, was not lower in these cattle than in untreated controls. It was concluded that the dosage regimen was inadequate to prevent infections occurring, perhaps because the drug concentrations were too low during the last third of inter-treatment intervals. It was recommended that isometamidium prophylaxis at 1.0 mgkg-1 body weight should be evaluated

A longitudinal study of disease incidence and case-fatality risks on small-holder dairy farms in coastal kenya

A longitudinal study was carried out in the coastal lowlands coconut-cassava agro-ecological zone of Kaloleni Division, Coast Province, Kenya between June 1990 and December 1991 to estimate disease incidence and cause-specific case-fatality risk in an average of 120 cattle in 26 small-holder dairy herds kept in two grazing-management systems. East Coast fever (ECF) was the predominant disease diagnosed; the mean monthly incidence rate was 2.5 and 6.9% in animals ≤18 months of age under stall-fed and herded-grazing systems, respectively. In cattle >18 months of age, the monthly incidence rate was 18 months averaged 9%. Cattle managed in the herded-grazing system had a 60% higher mortality, although not significantly so, than those fed in stalls. Deaths due to ECF accounted for over two-thirds of the deaths. ECF was then the major disease constraint to small-holder dairy production in the coconut zone of coastal Kenya. Clinical cases occur the whole year round (especially in young stock) - despite apparent tick control, and in both herded-grazing and stall-feeding system

Seroprevalences of vector-transmitted infections of small-holder dairy cattle in coastal Kenya

A cross-sectional study was carried out from July to September 1989 in Kaloleni Division, Coast Province, Kenya to estimate the prevalence of vector-transmitted diseases in small-holder dairy cattle and to identify the risk factors associated with different management systems. One hundred and thirty of the 157 herds with dairy cattle in Kaloleni Division were surveyed. These were from three agro-ecological zones (coconut¯cassava, cashewnut¯cassava and livestock¯millet), comprised two management systems (stall-feeding and herded grazing) and were herds with either dairy cattle only or with Zebu and dairy cattle. A formal questionnaire sought answers to questions on cattle health and management practices. A total of 734 dairy and 205 Zebu cattle in 78 dairy and 52 mixed (dairy and Zebu) herds were sampled and screened for haemoparasites (Trypanosoma, Anaplasma, Babesia, and Theileria infections). Sera were tested for antibodies to Theileria parva, using the schizonts-antigen indirect fluorescent-antibody (IFA) test and to antibodies for Babesia bigemina and antigens to Anaplasma marginale by enzyme-linked immunosorbent assay (ELISA). Packed-cell volume (PCV) also was measured. Tick-control measures were practised by all except three of the farmers. Despite this, overall seroprevalence to T. parva was >70% suggesting either that control practices were not strictly implemented or they were ineffective. The seroprevalence of T. parva in adult cattle kept in stall-feeding systems in the coconut¯cassava zone was significantly lower (57±8% (S.E.)) than in herded-grazing systems (79±3%) and there was no association between antibody prevalence and age of cattle in this zone. Antibody prevalences in cattle in the cashewnut¯cassava and the drier livestock¯millet zone increased with age. Cattle in herded-grazing systems had an overall lower seroprevalence of T. parva infection in the livestock¯millet zone (45±6%) than in the other two zones. Analysis was confined to the coconut¯cassava zone for B. bigemina and to the coconut¯cassava and cashewnut¯cassava zones for A. marginale. Mean prevalences of B. bigemina were 40.9±9 and 73±6% for dairy cattle under stall-feeding and herded-grazing systems, respectively, and increased with age. Antigen prevalences of A. marginale were over 80% in all age groups of cattle in the coconut¯cassava and cashewnut¯cassava zones. Overall trypanosome prevalence in cattle was <1%. Trypanocidal treatment was uncommon. The variations in antibody prevalence associated with risk factors such as feeding system, agro-ecological zone and age of animal suggest that management system influenced exposure to tick-borne infection (particularly, T. parva infections) in small-holder dairy cattle in coastal Kenya

Health and productivity of East African Zebu under village management in a tsetse area on the coast of Kenya

Evaluates the health and productivity of East African Zebu cattle under village management in a tse-tse infested area surrounding the Muhaka Forest on the Kenya Coast south of Mombassa, and assesses the cost-effectiveness of intervention with trypanocidal drugs

Production of marketable milk in the sub-humid tropics: experiences, lessons and technologies from coastal Kenya

The Kenya coastal region has a large, unsatisfied market for milk and dairy products. Between 1988 and 1994, a research project, closely linked to extension, identified and addressed technical constraints that limit smallholder dairy Development in the region. Methodological approaches are outlined. Smallholders found it difficulty to maintain the advantages of systematic crossbreeding. Research showed that rotational crossing was appropriate when AI is available. In its absence, crossbred bulls should be considered. A study of lifetime productivity demonstrated the major contribution that genetic improvement can make to increasing productivity. Systematic epidemiological studies identified East Coast fever (ECF) as the cause of serious production losses. The infection and treatment method of immunization was more effective than current control methods, and was accepted by smallholders. Compared to recommended practises, intercropping with legumes, and manure and legume mulch application, improved year - round feed availability for dairy cows. Feeding legume and maize bran supplements was very cost-effective. Through collaborative research-extension activities, legume technologies were extended to many smallholdings. The linkages with farmers will facilitate the Development and testing of other technologies. Finally, the importance of a favourable operational environment for smallholders is emphasised, including institutional structures to encourage effective research- extension- farmer linkages and policies to facilitate dairy market Development

Identification of a target population for immunisation against East Coast fever in coastal Kenya

Two experiments were carried out to identify the target population of cattle for immunisation against East Coast fever (ECF) using the infection-and-treatment method. Firstly, a sentinel-calf study was used to determine the age window for ECF immunisation by determining ages at clinical detection of infection with Theileria parva. Six groups of five naive cross-bred (Bos taurus/Bos indicus) male calves, introduced at intervals of 2 months at a mean age of 26 days, were exposed to natural tick challenge on a high ECF-risk, small-holder farm in the coastal lowland, coconut¯cassava agro-ecological zone of coastal Kenya. Secondly, a challenge study evaluated the relationship between the presence of T. parva antibodies and immunity. Ten indigenous adult Zebu cattle and nine Zebu young stock purchased from farmers in the same zone, and eight cross-bred calves (survivors of the sentinel-calf study) were challenged with 10 times the immunising dose of T. parva Marikebuni stock. Twenty-four of these 27 cattle had high antibody titres before challenge. Two cross-bred calves, obtained from an ECF-free area and seronegative to T. parva schizont antigen, also were challenged and used as susceptible controls. Twenty-five (83%) of the 30 sentinel calves contracted ECF over an age range of 36¯116 days (mean 72 days). The remaining five calves died of other causes within 2 months of arrival on the farm. Fourteen of the 25 calves survived the infection and developed antibodies to T. parva. Despite tick control, seven of these 14 calves had a second episode of ECF and two died. In total, 13 of the 25 calves that contracted ECF died. Only one of 19 indigenous Zebu animals developed clinical ECF when challenged with T. parva Marikebuni (mild clinical signs with spontaneous recovery). Of the eight cross-bred survivors from the first experiment, only one succumbed to ECF when challenged and it died. Both susceptible cross-bred calves developed severe clinical signs of ECF and one died. The experimental studies show that in the high ECF-risk areas of the coconut¯cassava zone of coastal Kenya, immunisation against ECF in cross-bred (B. taurus/B. indicus) cattle should be targeted at an early age (preferably within 1¯2 months of birth)

Research on smallholder dairy production in coastal lowland Kenya

This paper describes the origins and subsequent development of a collaborative programme of research on smallholder dairy production between KARI, ILCA and other cooperating institutions. The programme conducted research within a farming ystems framework in per-urban areas of coastal lowland Kenya. The integrated programme of on-farm and on-station research covers farming systems description and constraint identification, and technology development and testing. Major research areas centre on studies of milk consumption and marketing, smallholder resource management, disease risk to dairy cattle, feeding systems development and dairy cattle breeding. Results to date have confirmed the large milk deficit. East Coast fever has been shown to cause major losses in smallholder dairy cattle. The seasonal feed shortages and inadequate nutrient concentrations in milk produciton diets are being adressed through integrating crops and livestock by intercropping fodder grasses, maize and cassava with shrub and herbaceous legumes and the application of cattle manure. Rotational crossbreeding has been shown to be an efficient breeding system for smallholder milk production. Studies of current farming systems and the assessment of resource levels indicate that for the majority of households, agricultural change will be a sequential intensificaiton through the adoption of individual technological components rather than through the adoption of a multi-component package, such as the National Dairy Development Project's zero-grazing package