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SCIENTIFIC WORK |
M. Heinloo. |
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Visualization of the working process of a spreading disk of a disk spreader |
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This paper considers a spreading disk of a disk spreader. The mathematical model for study the working process of the spreading disk has been composed by Reintam (1995). This paper presents the method for creation of the video clip visualizing virtual working process of the spreading disk on the worksheet of Computer Package Mathcad. Keywords: agricultural machinery, disk spreader, spreading disk, visualization.
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https://agrt.emu.ee/pdf/2010_1_heinloo.pdf
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H. Kaldmäe, A. Olt, M. Ots, O. Kärt. |
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Different additives effects on quality of lucerne silage |
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Different additives effects on quality of lucerne silage. The effect of different commercial additives on silage fermentation and nutritive value was studied. Silage was prepared from lucerne with a dry matter content after 24 hours of wilting of 309 g kg−1 for the first cut, 506 g kg−1 for the second cut and 215 g kg−1 for the third cut. Test with four different inoculants were based on different strains of Lactobacillus plantarum which were used alone or in combinations with other lactic acid bacteria (BO, BI, SI, EC), and chemical additive (AIV Pro) were used. All commercial inoculants improved the fermentation quality of lucerne silage under the conditions stated. DM losses during fermentation were the lowest in silage treated with AIV Pro additive (2.6% in I cut; 2.3% in II cut and 3.2% in III cut. In silages treated with biological additives these values were BO I − 3.5%; II − 4.6%, III − 3.8%; BI I − 5.8%, II − 3.2%, III − 4.9%; SI I − 5.8%, II − 4.8, III − 5.2%; EC I − 4.2% II − 5.8%, III − 4.0%, respectively and in untreated silage (I − 6.8%, II − 6.5%, III − 4.5%). No important differences were found between organic matter digestibility of the inoculated and the control silage for the first, the second and the third cut. Digestibility of the lucerne silage treated with AIV Pro was higher than that of the control silage by 4.9% for the first cut and by 5.1% for the second cut and by 4.0% for the third cut (P<0.01). Keywords: lucerne silage, biological additive, fermentation, digestibily.
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https://agrt.emu.ee/pdf/2010_1_kaldmae.pdf
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S. Lehtsalu, T. Kaart, H. Kiiman. |
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Rearing female dairy calves from birth to first insemination |
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Rearing female dairy calves from birth to first insemination. Dairy calf and heifer management practices throughout the rearing process have an impact on the longevity of a dairy cow and the herd economy as a whole. Short rearing periods are desirable primarily from economic and genetic standpoints. Dairy calf growth rate is an indicator of the effectiveness of farm management. The aim of the present study was to assess the female dairy calf weight gain from birth to first artificial insemination on a production farm. Experimental data for this investigation were obtained from Halinga OÜ and Agroland SYD OÜ. The data included the birth weights of 67 and body weights of 55 Estonian Holstein female dairy calves from birth to on an average 763 days (determined using a tape measure once every 1.5 months). The statistical analyses of the data revealed that the average birth weight of a dairy calves was 36.3 kg. The birth weight of dairy calf did not have a statistically significant effect on the average daily gain. The average growth rate from birth to the first artificial insemination was 545 grams, thereby in the first year 684 and in the second year 384 grams. At the first insemination the average age of heifers was 22.7 months and body weight 414 kg. On an average the test bulls’ daughters were artificially inseminated 28 days earlier and at 26 kg lower body weight, compared with the daughters of the proven bulls. Keywords: female dairy calf, dairy farm, birth weight, body weight
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https://agrt.emu.ee/pdf/2010_1_lehtsalu.pdf
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M. Olle, I. Bender. |
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The effect of non-woven fleece on the yield and production characteristics of vegetables |
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The aim of present investigation was to give an overview about the effect of non-woven fleece on the yield and production characteristics of vegetables. Non-woven fleece increased early yield, total yield, germination, development and growth speed, plant height, number and area of leaves of plants and protects against low temperature and frost. Use of nonwoven fleece reduced insect pests damage, and protection quality regarding to lower content of pigments, vitamin C, dry matter and sugar. Keywords: vegetables, non-woven fleece, yield, quality, production characteristics.
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https://agrt.emu.ee/pdf/2010_1_olle.pdf
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P. Padrik, T. Hallap, T. Bulitko, T. Kaart, Ü. Jaakma. |
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CVM-genedefect and grade of Holstein genes in relation to sperm quality characteristics of Estonian Holstein dairy bulls |
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CVM-genedefect and Grade of Holstein Genes in Relation to Sperm Quality Characteristics of Estonian Holstein Dairy Bulls. The aim of the current study was to investigate the influence of CVM- (Complex Vertebral Malformation.) genedefect and grade of Holstein genes on sperm motility, membrane integrity, membrane lipid architecture status and mitochondrial membrane potential in frozen-thawed (FT) semen, collected from Estonian Holstein (EHF) bulls. Thirty six ejaculates from 13 EHF bulls age (14–44 months) were examined for motility (using a computer assisted motility analyzer (CMA)), hypo-osmotic swelling (HOS), membrane lipid architecture status (Merocyanine 540 staining) and mitochondrial membrane potential (Mitotracker Deep Reed 633 staining). The results showed a significant difference in the incidence of sperm linearity, (LIN), amplitude of lateral head displacement (ALH), plasma membrane integrity (HOS), membrae stability (LSM) and mitochondrial activity (MTDR-H (P<0.05)) between the bull groups with the different grade of Holstein genes. The bull groups with and without CVM carriers differed in the incidence of general motile (GMot) and progressively motile (PMot), spermatozoa, curve line velocity (VCL),(P<0.001). The results showed positive correlation between results of GMo,PMot, VCL, ALH, LSM, MTDR-H and NRR (non return rate 60- day). Strong positive correlation was found between PNRR (predictive non-return rates) and NRR (P<0.001). We conclude that the bulls' grade of Holstein genes and CVM-genedefect have an effect on sperm quality parameters. Frozen/thawed sperm motility parameters, LSM and MTDR-H are related to NRR of cows and heifers and could be used for the prediction of bull's fertility. Keywords: Bull, Sperm quality, Grade of Holstein Genes, CVM.
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https://agrt.emu.ee/pdf/2010_1_padrik1.pdf
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P. Padrik, T. Hallap, T. Bulitko, Ü. Jaakma. |
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Influence of bull age and season to frozen-thawed semen quality and fertility |
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Influence of bull age and season to frozen- thawed semen quality and fertility. The aim of the current study was to investigate the influence of season and bull age to sperm motility, membrane integrity, membrane lipid architecture status and mitochondrial membrane potential characteristics in frozen-thawed (FT) semen, collected from Estonian Holstein (EHF) bulls. Forty five ejaculates from 15 (1–7 years) EHF bulls were examined for motility (objectively using a computer assisted motility analyzer (CMA)), hypoosmotic swelling (HOS), membrane lipid architecture status (Merocyanine 540 staining) and mitochondrial membrane potential (Mitotracker Deep Reed 633 staining). Stained spermatozoa were assessed by FCM (flow cytometry). The results of the study showed that the increase in bulls' age from 1–2 years to 5–7 years was accompanied by the increase in general motility (GMot), membrane stability (LSM) and mitochondrial activity (MTDR-H)(P<0.05), curve line velocity (VCL; P<0.01), linearity (LIN) and amplitude of lateral head displacement (ALH; P<0.001) on batch level. The quality of spermatozoa in FT samples varied between the seasons. The mean values for VCL, ALH and MTDR-H were higher in winter and autumn on both batch and bull level (P<0.05). In relationship with NRR (nonreturn rate 60-day), strongest correlation was obtained for the ALH results on bull level (P<0.001). We conclude that the bulls' age and season of semen collection have an effect on sperm quality parameters. Frozen/ thawed sperm motility parameters, LSM and MTDR-H are related to NRR of cows and heifers and could be used for the prediction of bull's fertility. Keywords: Bull, Sperm quality, Age, Season, Fertility
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https://agrt.emu.ee/pdf/2010_1_padrik2.pdf
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R. Põldaru, T. Roosmaa, J. Roots. |
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Modelling of milk purchase price in Estonia |
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Milk purchase price is an essential indicator which characterises the situation in dairy sector. The primary objective of the present study was the creation of an experimental econometric model of milk purchase price in Estonia. The model was created using the macro-econometric model for the Estonian dairy sector, which outlines the linkage between the milk purchase price and input factors: cheese and butter prices in the European market and barley price in Estonian market. Nonlinear equations (Cobb-Douglas function) enable to analyse the formation of milk purchase price in detail. The stochastic equations are estimated by full information maximum likelihood (FIML) method. The equations were estimated using data from 1992 to 2008 inclusive. The parameters of structural equation of milk purchase price have theoretically consistent signs and are significant. Projections for the milk purchase price are run out over a five-year period. Using the isoprice curves, the impacts of an increase in the price of cheese, price of butter and price of barley to milk purchase price are evaluated. The possible substitution values between two different inputs (price of cheese, price of butter and price of barely in different combinations) are evaluated. Some results from those evaluations are then presented. Perspective implementation of milk purchase price model is discussed. The milk purchase price model for the Estonian agriculture may be used for projection and analysis purposes. Keywords: Dairy sector, milk purchase price, macroeconomic modelling, simultaneous equations, isoprice curve
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https://agrt.emu.ee/pdf/2010_1_poldaru.pdf
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K. Tamm. |
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The dependence on the structure of machinery and the locality of plots on cereal farm work activities |
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This is an overview paper about thesis for applying for the degree of Doctor of Philosophy in Agricultural Machinery; defended on 2009 in Estonian University of Life Sciences. The dominant trend of enlarging the production area of farms is causing a growth in transportation costs making the profitability of cultivating distant plots questionable. The aim of this study was to provide a method to evaluate the rationality of using a plot depending on its distance, area and cultivation technology. A mathematical model was composed to calculate the total costs depending on the distance to the plot. The transportation costs of machines and materials, cost of management travel and timeliness costs are taken into account in the model to enable determination of the maximum distance or the minimum area of the plot necessary for profitable cultivation. On the basis of the calculations performed by means of the model, it can be concluded that the profitable distance increases with plot size. In the economic conditions used in the thesis, the economically maximum distance for plots over 25 ha falls within the interval of 18–25 km. Simulations allow us to conclude that the growth in yield and selling price of the production allow an increase in the limit value of driving costs and, thus, the profitable distance of the plot; on the other hand, it means also an increase of timeliness costs as a limitation for extending distance. Exploitation of more distant plots can be uneconomical in coming years because of increasing fuel costs. Keywords: farm size, plot, distance, transport costs, timeliness, economic evaluation, mathematical models.
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https://agrt.emu.ee/pdf/2010_1_tamm.pdf
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R. Vettik. |
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Computer-aided optimization of pig farming technologies and machinery use |
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This is an overview paper about thesis for applying for the degree of Doctor of Philosophy in Agricultural Machinery; defended on 2007 in Estonian University of Life Sciences. The aim of this thesis was to develop methods for finding optimum values for parameters characterising different pig farming technologies (time consumption of human work, need for feed, necessary area of arable land etc) in a company involved in pig farming and crop growing. This research work deals the creation of the methodology and the respective computer software application, by means of which it is possible to find the optimum size of a grain growing and pig farming company in the case of different grain yield levels and pig farming technologies, depending on the length of the working day during top load period, and also considering the restrictions on the use of manure proceeding from the environmental protection requirements established in Estonia. The calculation results revealed that a pig farming and crop growing company with one employee, in which also the main feed for pigs is produced, cannot provide sufficient workload for the machinery based on a 60-kW tractor. For the better loading of the machinery the area of arable land should be larger. But the working time left for crop growing works does not enable it. Therefore extra labour force should be used in the high season of crop farming works (sowing and harvesting). Another possibility would be to increase the proportion of purchased feeds. Keywords: pig farming technology, time consumption of human work, regression equation, feed consumption, grain yield, workload of machinery, slurry utilization
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https://agrt.emu.ee/pdf/2010_1_vettik.pdf
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