Constraints on smallholder market oriented dairy systems in the north eastern coastal region of Tanzania

Twenty five smallholder dairy farmers and other stakeholders, through a Participatory Rural Appraisal in three wards of the Tanga township of north east coastal Tanzania, ranked their perceived constraints in descending order of importance: Low milk price and marketing, feed shortage in the dry season, poor management, low animal productivity, poor reproductive performance and diseases. Tick borne diseases were reported on a majority of farms. An Economic Opportunity Survey revealed wide ranges in management indices and improvement in annual milk production, age at first calving and lactation length to represent the best potential for gain. Performance generally was below locally set targets. Farmers spent on average in the three wards between 39% and 77% of income from milk on feed costs yearly. Interventions were instituted emphasising those that farmers could afford immediately. They included farmer training, dry season feed supplementation, tick control, improvement of animal shed/house cleanliness and the formation of a cooperative for milk marketing. Partial budgeting is being used to monitor success. Follow-up meetings and regular visits to farms by field officers are disseminating information on outcomes to encourage farmers to continue with interventions and spread useful knowledge to friends and neighbours.     

Trypanosomosis prevalence in cattle on Mafia Island (Tanzania)

During two consecutive surveys (February and August/Sept 2002), a total of 970 cattle from the cattle population of Mafia Island (United Republic of Tanzania) were blood-sampled. All blood samples were microscopically screened for the presence of trypanosomes and a portion of these were checked for antibodies with an Ab-ELISA and for the presence of trypanosomal DNA with PCR. Microscopic evidence of trypanosomes of the congolense group (sub-genus Nannomonas) was found in 0.8% of the animals (8/970) and in two cases the species identified was confirmed by PCR as Trypanosoma congolense savannah type. Non-pathogenic Trypanosoma theileri were detected in 3.2% (31/970) of the samples using the Dark Ground-Buffy Coat (DG-BC) technique. For survey 1 (S1), detection of antibodies (Ab-ELISA) against pathogenic trypanosomes indicated a seroprevalence of 14.2% (68/480). Of the samples, either DG positive or with a PCV lower then 25, examined by PCR, a total of 8.4% (5/59) (selected from 970 samples), were found positive for T. congolense. The low prevalence of pathogenic trypanosomes on Mafia Island is intriguing, especially in view of the omnipresence of the tsetse fly Glossina brevipalpis. Although the presence of detected trypanosomal antibodies does not necessarily indicate a current infection, the combination of serological/parasitological examinations and the results of the PCR do support this low prevalence of trypanosomosis in cattle. Despite the low prevalence, pathogenic trypanosomes are present on Mafia Island and possible reasons for this low infection rate, taking account of the relation between Glossina species present, transmission risk and trypanosomes found in cattle, are discussed also in view of a future appropriate intervention strategy.     

Some Factors Affecting Variation in Milk Yield in Crossbred Dairy Cows on Smallholder Farms in North-East Tanzania

A 2-year longitudinal survey was carried out to investigate factors affecting milk yield in crossbred cows on smallholder farms in and around an urban centre. Sixty farms were visited at approximately 2-week intervals and details of milk yield, body condition score (BCS) and heart girth measurements were collected. Fifteen farms were within the town (U), 23 farms were approximately 5 km from town (SU), and 22 farms approximately 10 km from town (PU). Sources of variation in milk yield were investigated using a general linear model by a stepwise forward selection and backward elimination approach to judge important independent variables. Factors considered for the first step of formulation of the model included location (PU, SU and U), calving season, BCS at calving, at 3 months postpartum and at 6 months postpartum, calving year, herd size category, source of labour (hired and family labour), calf rearing method (bucket and partial suckling) and parity number of the cow. Daily milk yield (including milk sucked by calves) was determined by calving year (p < 0.0001), calf rearing method (p = 0.044) and BCS at calving (p < 0.0001). Only BCS at calving contributed to variation in volume of milk sucked by the calf, lactation length and lactation milk yield. BCS at 3 months after calving was improved on farms where labour was hired (p = 0.041) and BCS change from calving to 6 months was more than twice as likely to be negative on U than SU and PU farms. It was concluded that milk production was predominantly associated with BCS at calving, lactation milk yield increasing quadratically from score 1 to 3. BCS at calving may provide a simple, single indicator of the nutritional status of a cow population.     

Land Cover Change Impacts on Beef Cattle Productivity under Changing Climate: Case of Ilemela and Magu Districts,Tanzania

The study focused on contributing to the spatial knowledge of the impacts of land cover changes on beef cattle production under a changing climate in rangelands of the Lake Victoria Basin (LVB), so as to establish a strategy for improving beef cattle production in the area. We used supervised classification of satellite imagery to analyze land cover changes between the years 1980–2000 and 2000–2010. Results revealed that for the periods 1980–2000 and 2000–2010, settlements increased by 1% and 8%, and cultivated area increased by 0.58% and 0.30%, respectively. Riverine vegetation declined by 0.26% and increased by 0.16%, and woodlands declined by 6% and 13% respectively. The trend of beef cattle numbers against rainfall and pasture area (riverine vegetation and woodland) over the study period 1980–2010 showed a non-significant trend of increasing rainfall in the study area. In Ilemela District, pasture area and beef cattle numbers declined by 33% and 4% respectively. In Magu District, beef cattle numbers increased by 64% and pasture area declined by 84%. This implies that the effect of urbanization is more severe in Ilemela than in Magu District. Land use planning, enhancing of mixed crop-livestock farming systems, intensification of livestock practices, forage conservation, planting of fodder trees, and matching of cattle numbers with pasture availability are recommended. In addition, education is needed on effective cattle farming as a strategy for improving beef cattle production in the face of land cover changes due to climate variability in the area.     

Economics of rainwater harvesting for crop enterprises in semi-arid areas of East Africa

This paper presents an analysis of economics of rainwater harvesting by poor farmers in Tanzania. A questionnaire was used to survey 120 households to obtain information on the performance of their enterprises over 6 years (1998–2003). The information was mainly based on recollection as few farmers kept detailed records. Actual monitoring and measurements of yield and inputs was done in the farmers’ enterprises over 2 years during 2002/2003 and 2003/2004 production seasons. The analysis was done for four categories of rainwater harvesting systems differentiated by the size of catchments from which water is collected and the intensity of concentration and/or storage of the collected rainwater. These categories are: micro-catchments, macro-catchments, macro-catchments linked to road drainage and micro or macro-catchments with a storage pond. Results show that rainwater harvesting for production of paddy rice paid most with returns to labor of more than 12 US$ per person-day invested. These benefits are very high due to the fact that without rainwater harvesting it is not possible to produce paddy in the study area and rainfed sorghum crop realizes a return to labor of only US$ 3.7 per person-day during above-average seasons. For the rainwater harvesting systems, those designed to collect water from macro-catchments linked to road drainage, performed best during both categories of seasons. The results also show that contrary to expectations, improving rainwater harvesting systems by adding a storage pond may not lead to increased productivity. Another finding that goes against the widely held belief is that rainwater harvesting results in more benefits during the above-average seasons compared to below-average seasons. It is therefore, concluded that there is a potential for combining rainwater harvesting with improved drainage of roads. The construction of rural roads in semi-arid areas can beneficially be integrated with efforts to increase water availability for agricultural needs.     

Can the parasitic weeds Striga asiatica and Rhamphicarpa fistulosa co‐occur in rain‐fed rice?

Striga asiatica and Rhamphicarpa fistulosa are important parasitic weeds of rain‐fed rice, partly distributed in similar regions in sub‐Saharan Africa (SSA). It is not evident whether their ecologies are mutually exclusive or partially overlapping. In Kyela, a rice‐growing area in south Tanzania where both parasites are present, three transects of about 3 km each across the upland–lowland continuum were surveyed in June 2012 and 2013. A total of 36 fields were categorised according to their position on the upland–lowland continuum as High, Middle or Low and soil samples were taken. In each field, parasitic and non‐parasitic weed species were identified in three quadrats. Additionally, in two pot experiments with four different moisture levels ranging from wilting point to saturation, influence of soil moisture on emergence and growth of parasites was investigated. Striga asiatica was observed in higher lying drier fields, while R. fistulosa was observed in the lower lying wetter fields. Furthermore, non‐parasitic weed species that were exclusive to S. asiatica‐infested fields are adapted to open well‐drained soils, while species that were exclusive to R. fistulosa fields are typical for wet soils. The experiments confirmed that S. asiatica is favoured by free‐draining soils and R. fistulosa by waterlogged soils. These results imply that changes in climate, specifically moisture regimes, will be crucial for future prevalence of these parasitic weeds. The non‐overlapping ecological range between their habitats suggests that their distribution and associated problems might remain separate. Thus, management strategies can be focused independently on either species.     

Some Factors Affecting Reproductive Success in Crossbred Dairy Cows on Smallholder Farms in Coastal North-East Tanzania

A 2-year longitudinal survey was carried out to investigate factors affecting reproduction in crossbred cows on smallholder farms in and around an urban centre. Sixty farms were visited at approximately 2-week intervals and details of reproductive traits and body condition score (BCS) were collected. Fifteen farms were within the town (U), 23 farms were approximately 5 km from town (SU), and 22 farms approximately 10 km from town (PU). Sources of variation in reproductive traits were investigated using a general linear model (GLM) by a stepwise forward selection and backward elimination approach to judge important independent variables. Factors considered for the first step of formulation of the model included location (PU, SU and U), type of insemination, calving season, BCS at calving, at 3 months postpartum and at 6 months postpartum, calving year, herd size category, source of labour (hired and family labour), calf rearing method (bucket and partial suckling) and parity number of the cow. The effects of the independent variables identified were then investigated using a non-parametric survival technique. The number of days to first oestrus was increased on the U site (p = 0.045) and when family labour was used (p = 0.02). The non-parametric test confirmed the effect of site (p = 0.059), but effect of labour was not significant. The number of days from calving to conception was reduced by hiring labour (p = 0.003) and using natural service (p = 0.028). The non-parametric test confirmed the effects of type of insemination (p = 0.0001) while also identifying extended calving intervals on U and SU sites (p = 0.014). Labour source was again non-significant. Calving interval was prolonged on U and SU sites (p = 0.021), by the use of AI (p = 0.031) and by the use of family labour (p = 0.001). The non-parametric test confirmed the effect of site (p = 0.008) and insemination type (p > 0.0001) but not of labour source. It was concluded that under favourable conditions (PU site, hired labour and natural service) calving intervals of around 440 days could be achieved.     

Fish to 2030: The Role and Opportunity for Aquaculture

Seafood sector can contribute to the global food supply in an important way, and provide an important source of animal protein. Based on observed regional trends in seafood production and consumption and using a global, partial-equilibrium, multi-market model, this study investigates what the global seafood market may look like in 2030. The model projects that the total fish supply will increase from 154 million tons in 2011 to 186 million tons in 2030, with aquaculture entirely responsible for the increase. The fastest aquaculture growth is expected for tilapia and shrimp, while the largest expansion is expected in India, Latin America and Caribbean and Southeast Asia. Fast-growing seafood demand in China and elsewhere represents a critical opportunity for global fisheries and aquaculture to improve their management and achieve sustainable seafood economy.     

The Effects of a Short-term Increase in Supplementation on the Reproduction Performance in Lactating Crossbred Dairy Cows

The hypothesis that dairy cows partially suckling their calves would ovulate following removal of calves when restored to positive energy balance by a short-term increase in supplementation was investigated in 65 crossbred cows. Five treatments (T1, T2, T3, T4, and T5) that differed in the amount of total concentrate fed from calving to week 24 were involved. Calves were allowed to suck residual milk to 12 weeks of age. Energy balance was estimated by measuring intake, milk yield and organic matter digestibility. The occurrence of ovulation was determined by the analysis of milk progesterone (P4) concentration. Four groups that were receiving additional supplementation were restored to positive energy balance, while the control group (T1) remained in negative energy balance. The percentage of cows ovulating was 36%, 58%, 92%, 90% and 60% for T1, T2, T3, T4 and T5, respectively (p = 0.026). Comparison of the timing of ovulation for combined results from T1+T2 and T3+T4+T5 estimated mean time to fail to ovulate as 110+/-9.0 and 87+/-7.6 days, respectively (p = 0.023). The percentage of the cows showing oestrus was 9%, 8%, 33%, 40% and 40% for T1, T2, T3, T4 and T5, respectively (p = 0.197). Short-term increases in supplementation are unlikely to be an attractive means of reducing calving intervals.     

应用核不育技术根治桑给巴尔采采蝇

:1 994年开始应用昆虫不育技术根治坦桑尼亚桑给巴尔的温古贾岛采采蝇(GlossinaausteniNewstead)项目。该项目在坦桑大陆东北部建立了采采蝇人工大量繁殖、辐射不育设施 ,在温古贾岛上空用轻型飞机航空释放雄性不育采采蝇。在全岛设立多达 70 0个粘虫板 ,监测野生和不育采采蝇种群 ,同时在 38个监测区用MHCT等技术监测采采蝇传播的家畜锥虫病。释放了约 80 0万只雄性不育采采蝇。南半岛不育 /野生的雄蝇比由 1 995年中期前的小于 2 0 / 1上升到大于 1 0 0 / 1 ,导致雌蝇诱导不育率快速上升。野生采采蝇密度于 1 996年初开始急速下降 ,最后 1只野生雄性和雌性采采蝇分别于 1 996年第 32、36周捕获。锥虫病发病率也降至 1 %以下 ,而且仅限于Trypanosomavivax。在最后 1只野生采采蝇捕获约 6代的时间后 ,于 1 997年 1 1月底停止航空释放雄性不育采采蝇 ,经独立专家组评估后 ,正式宣告桑给巴尔采采蝇已被根治