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The productivity and management systems of free range local chickens in rural areas of Babati District, Tanzania Full text
2018
Marwa, L.J. | Mbaga, S.H. | Mutayoba, S.K. | Lukuyu, Ben A.
Performance evaluation of Abergelle goat under community based breeding program in selected districts, northern Ethiopia Full text
2018
Birhanie, Minister | Alemayehu, Kefyalew | Mekuriaw, Getinet
Milk production performance of Begait goat under semi intensive and extensive management in Western Tigray, North Ethiopia Full text
2018
Hagos, A. | Gizaw, Solomon | Urge, Mengistu
The study was conducted in Kafta humera district of Ethiopia, (i) to investigate the milk yield of Begait goat under different management and (ii) to evaluate the effects of different non-genetic factors on lactation performance. Data were collected from 428 lactating does under two managements (semi intensive and extensive) during October 2014 and March 2016. Statistical analyses were carried out using the GLM procedure of SAS version of 9.2 software. The least squares means (with standard error) for daily milk yield, lactation milk yield and lactation length were observed to be 0.75±0.01 kg, 85.6±1.04 kg and 111±1.21 days under semi intensive management, respectively whereas under extensive management these were found as 0.55±0.01 kg, 56±1.43 kg and 101±1.57 days, respectively. The results of this study indicated that management system, parity number and season of birth affected all variables highly significantly.
Show more [+] Less [-]Gender aspects in the dairy value chain in Tanzania: A review of literature Full text
2018
Sikira, A.N. | Waithanji, Elizabeth M. | Galiè, Alessandra | Baltenweck, Isabelle
Economic values of Begait cattle breeding-objective traits under low and medium input production systems in northern Ethiopia Full text
2018
Mezgebe, Gebretnsae | Gizaw, Solomon | Urge, Mengistu
The study was conducted to estimate the economic values (EV) of Begait cattle breeding-objective traits and their effects on the returns to investment in breeding programs using bio-economic model. Production systems were described according to their level of input and sale age, namely, low input herd management (LIHM) and medium input herd management (MIHM) based on fixed herd size for genetic improvement of multiple traits. Results showed that all considered traits have positive economic values across production systems except pre weaning daily body weight gain (PrDG). However, production systems had significant influence on the magnitude of EV of traits. The MIHM was superior by 100 to 9% to the LIHM system. Regardless of the two production systems, calving interval (CI) had the highest EV followed by dressing percentage (DP) and mature weight (MWT). Although, the overall change of beef trait EV influenced the marginal profit through price and production variable changes at constant MY, the more sensitive change was observed with the changes of MY EV. Traits of milk yield had 1 to 12% increment on profit with 1 to10% improvement in its EV by rising milk price, reduced weaning and reduced culling rates. However, beef traits only made 5.1×10-7 to 2.3×10 -6% raises on profits with 18 to 50% increment in its EV by beef price increment and reduced age at first calving. The higher increments of profit parallel to the EV of milk production trait and mostly simultaneous improvements on CI have a great indication to give priorities on milk yield traits than beef traits in any Begait cattle improvement program. Therefore, improving milk production traits and fecundity traits simultaneously with their market outlet is better to increase the profitability of farmers and sustains the valuable breed in their habitat.
Show more [+] Less [-]Improved activity data for accounting greenhouse gas emissions due to management of wetlands Full text
2018
Butlers, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Ivanovs, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The study represents results on remote sensing methods based evaluation of land use and land use changes in former and existing peat extraction areas in Latvia. The aim of the study is to elaborate activity data set for the National GHG inventory for the wetlands remaining wetlands for peat extraction. The study results provide sufficient data for application of the default emission factors for the peat extraction sites and flooded lands. Abandoned peat extraction fields, which are not yet afforested, flooded or rewetted, should be reported as peat extraction sites following a conservative approach in application of the emission factors. The study results can be used to report land use changes since 1990; however, linearized approach in calculation of the land use change may result in overestimation or underestimation of GHG emissions in certain periods of time. According to study results, the area of peat extraction sites is considerably bigger than currently reported in the National GHG inventory, mainly due to considerable areas of abandoned peat extraction fields. Flooded lands may be a significant source of emissions and should be introduced in the National GHG inventory to secure consistency of reporting. Methodology for calculation of GHG emissions from flooded lands should be also elaborated. It is also necessary to elaborate emission factors for fertile and no fertile peat extraction sites and continue work on separation of different soils in the inventory to increase accuracy of calculations.
Show more [+] Less [-]Recent land cover changes in Latvia Full text
2018
Baders, E., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lukins, M., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Zarins, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Krisans, O., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Jansons, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Jansons, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Increase in use of biomass as renewable source of energy in Europe is tightly linked to the policies aimed at mitigation of climate changes i.e. reductions of greenhouse gas emissions. Both for assessment of the carbon sequestration and emissions as well as for assessment of potential amounts of biomass for renewable energy, information of land cover dynamics are essential. Therefore, the aim of our study was to improve accuracy of estimates of the land use changes in the time period between 1990 and 2014. Land use categories were determined in accordance to UNFCCC: wetland, cropland (arable land, bare field), forest, grassland, settlements (urban/suburban area), and other land. Combination of data from National forest inventory (NFI) sample plots and analysis of Landsat images were used. For the classification based on Landsat images vegetation index (NDVI) was estimated and linked to known information on the land use type from NFI sample plot data. In the analysed period, the most significant changes were found for forest lands – the total area of forest land during the last two decades had increased by 1% (64.5 thousand ha). Similar increase (1.2%) was observed also in the area of cropland. Both of these tendencies were primarily the result of marginal field area reduction (by 2.6%). Increase in forest area and thus annual increment has led to an increase in above-ground biomass by 10.2 m**3 haE-1.
Show more [+] Less [-]Forest regeneration quality – factors affecting first year survival of planted trees Full text
2018
Dumins, K., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdina, D., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The early stage of forestry is crucial for successful and sustainable forest management. One third of the reforested forest in Latvia is regenerated by planting with different kinds of tree seedlings. The success of forest regeneration by planting depends on correctly prepared soil and choice of the right seedling material. The aim of this study was to evaluate the impact of different soil preparation methods and used type of seedlings on tree survival and growth rate after the first growing season. For this study six young stand sites located in the north-west and central part of Latvia were established in three forest types and in each site soil was prepared in furrows by disc trenching, in mound and left untreated. Reforestation was conducted in the spring of 2017 with four tree species Picea abies, Pinus sylvestris, Alnus glutinosa and Betula pendula and three seedling types were used, bare roots, containerized and improved root system. The evaluation of survival and measure of annual increment was conducted at the end of the first growing season in the autumn of 2017. Results showed that overall the highest seedling survival rate provided soil prepared in mound (90%), and seedlings with improved root system, though the lowest survival rate was observed for bare root seedlings. Containerized seedlings have a higher proportional increment if compared to bare root and improved root system seedlings, but differences are not significant yet (p is greater than 0.05). In conclusion, the survival rate of outplanted seedlings differs by chosen stocktype and soil preparation method used in forest regeneration and for various tree species impact of chosen stock type on survival rate differs.
Show more [+] Less [-]Characteristic of browsing damages in Norway spruce stands Full text
2018
Desaine, I., Skogssallskapet, SIA, Riga (Latvia) | Baders, E., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Katrevics, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Smilga, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Jansons, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Browsing damages are becoming more common due to almost doubling of population densities of cervids in Latvia during last 20 years; however, the figures are still lower than those observed in western and northern European countries. Consequently, the frequency of damages in young stands is increasing, too. Protection against browsing becomes more difficult, as the trees grow older; also the bark-stripping may result in a long-term deterioration of stem quality. Therefore, the aim of the study was to assess the factors affecting bark striping damages in pole-stage Norway spruce stands. Data were collected in 4 sample plots in damaged Norway spruce stands in western Latvia, measuring the tree parameters: height, diameter, branch characteristics and damage parameters: size, proportion from the stem circumference. Results of the modelling reveal that both damage parameters were significantly influenced by the branch length and thickness in the whorl closest to the breast height and the size of damages – also by breast height diameter of the tree. It suggests that increasing productivity of trees would not reduce the browsing problem. Since the silvicultural goal is the reduction of the size of branches, especially in bottom-log of the stem, protection against bark-stripping needs to be developed and cervid population densities controlled to reduce the problem.
Show more [+] Less [-]Effect of thermal treatment on physical and mechanical properties of birch and pine wood Full text
2018
Antons, A., Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Cirule, D., Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Verovkins, A., Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Kuka, E., Latvian State Inst. of Wood Chemistry, Riga (Latvia);Riga Technical Univ. (Latvia)
No simple method has yet been found for satisfactory wood bio-resistance improvement regarding material performance in its end-use. An attempt to obtain material with proper strength and bio-durability by combined wood thermal modification and impregnation with a biocide is being researched. To select the most appropriate treatment conditions for the combined process, changes in wood physical and mechanical properties depending on the treatment temperature were investigated in the present study. For the investigation, in Latvia the most widespread wood – softwood pine (Pinus sylvestris L.) and hardwood birch (Betula spp.) was used. Changes of wood mechanical and physical properties due to thermal modification were investigated and effect of treatment temperature and relative humidity on wood characteristics evaluated. It was found that, due to different degree of changes, no identical treatment conditions suit for birch and pine wood. Birch wood is considerably more sensitive to temperature and acceptable strength was maintained only for birch wood treated at 150 °C and for pine wood treated at 160 °C. Nevertheless at higher environmental humidity equilibrium moisture content and consequently radial and tangential swelling increased for all studied wood types, substantially smaller changes due to elevated humidity were detected for modified wood.
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