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Draft resistance of the ploughs depending on soil friction
2008
Rucins, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Vilde, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
By using analytical correlations derived as a result of theoretical research, a computer algorithm has been worked out for simulating the functions of the plough body and the forces exerted by soil upon the operating parts, as well as its draft resistance. These correlations allow to determine the draft resistance of the plough depending on the parameters of its body, as well as to evaluate the impact of the physical and mechanical properties of soil, such as friction upon it. The greatest influence upon the draft resistance is exerted by soil hardness, density and slip resistance along the surfaces of the operating parts. The latter is also affected by soil adhesion, which particularly manifests itself in wet clay soils at lower temperatures. It has been clarified that the friction resistance constitutes 46–62% of the total draft resistance of the plough body. The main ways of lowering the friction resistance and the total draft resistance of the plough are the introduction of a more rational design of its body having optimum parameters, decreasing the resistance of the share-mouldboard surface and the values of reactions of the supporting surfaces, as well as the application of antifriction materials and better modes of joining with tractors.
显示更多 [+] 显示较少 [-]Inflammatory factors and apoptosis in the cow's endometrium in postparturition period
2008
Sematovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Jemeljanovs, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Pilmane, M., Riga Stradins Univ. (Latvia)
Nine multiparous cows were biopsied twice – in the first and fifth week after parturition in winter 2004/2005 on the Research and Study farm Vecauce of Latvia University of Agriculture. The aim of the research was to reveal distribution of inflammatory factors and apoptosis in the cow’s endometrium in post parturition period. Haematoxylin and eosin were used for routine staining of each sample. Tumor necrosis factor α (TNFα, w.d. 1:100, Abcam, England), and interleukin 10 (IL10, w.d. 1:400, Abcam, England) were detected immunohistochemically (IMH), and TUNEL method was used for detection of apoptosis. Distribution of these factors and substances was determined semiquantitatively by counting positive structures in visual fields. A significant increase in the total amount of inflammatory cells, as well as in the amount of the TNFα and apoptotic cells in endometrium between the first and fifth week after parturition (p is less than 0.01) was observed. A significant positive correlation (r=0.41; p is less than 0.01) between infiltration of endometrium with neutrophils and with macrophages was detected in the first week after parturition. A mild positive correlation (r=0.52; p is less than 0.01) between neutrophils and lymphocytes, as well as between lymphocytes and macrophages (r=0.35; p is less than 0.01) was found four weeks after parturition. A mild positive correlation (p is less than 0.05) was observed between amount of inflammatory cells and TNFα (r=0.52), and number of apoptotic cells and TNFα (r=0.58). The research suggests that inflammatory factors and apoptosis intensively act during the process of involution in the cows’ endometrium from the first up to the fifth week after parturition. Intensity, amount and activity of these components show individual variations in each case.
显示更多 [+] 显示较少 [-]Effects of topical and systemic atropine [sulphate] on intraocular pressure and pupil diameter in dog's eye
2008
Kovalcuka, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Birgele, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
The objective of this study was to determine the effects of topical 1% atropine sulphate and systemic atropine sulphate on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in dog’s eyes. Ten adult dogs for each treatment were used in this study. Dogs of different age, breed and sex were examined clinically and ophthalmologicaly. All animals were clinically and ophthalmologically healthy. One drop of topical 1% atropine sulphate was used in ten dogs unilaterally, with the contralateral eye acting as a control. IOP and HPD were measured every 5 minutes. In ten dogs systemic atropine sulphate were used intramuscularly (IM) with IOP and HPD measured every 5 minutes. In both study phases IOP and HPD were measured over a total duration of 60 minutes. After unilateral application of topical atropine, IOP increased significantly in the treated eye. A maximum average IOP of 20.3 mmHg in the treated eye was observed 20 minutes after treatment. Maximal pupil dilatation in the treated eye was observed 35 min after treatment. Measurements made after systemic atropine showed an IOP increase in both eyes, showing maximum average IOP increase 25 minutes post-treatment. Maximum average values of HPD were obtained 25 minutes after treatment. The HPD started to decrease 30 minutes after treatment but it was still significantly higher than before treatment (P is less than 0.05). Because of atropine sulphate’s ability to cause significant increase in IOP, it should not be used for diagnosis and treatment of glaucomatous eyes.
显示更多 [+] 显示较少 [-]Effect of storage time, temperature and solvent on the stability of sterigmatocystin standard solutions
2008
Versilovskis, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Mikelsone, V., Latvia Univ. of Agriculture, Jelgava (Latvia)
The influence of solvent, storage time and temperature on the stability of the mycotoxin sterigmatocystin (STC) was investigated. STC calibrants (1.0 μg mlE-1) in acetonitrile, methanol and mixture of acetonitrile and methanol (50:50, volume/volume) were stored in dark glass bottles at (– 25), 4 and 25 °C for up to 8 weeks. Samples were analysed by high performance liquid chromatography (HPLC) with ultraviolet (UV) detection. Obtained results indicate that more suitable solvents for storage of STC standard solutions at (–25 °C) are acetonitrile and mixture of acetonitrile and methanol (50:50, v/v), but not longer than for one week; for storage at 4 °C more suitable is mix of acetonitrile and methanol, but not longer than for one week.
显示更多 [+] 显示较少 [-]The evaluation of sensory properties of Latvian semi-hard cheeses
2008
Novikova, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Strautniece, E., Latvia Univ. of Agriculture, Jelgava (Latvia) | Cirovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Annual judging of dairy products including sensory evaluation of local cheese-maker' cheeses proved that the quality of Latvian classical cheeses is various. In fact, in last three competitions three different manufacturers gained the first place in category of Krievijas and Holandes types' cheeses. It indicates instability of Latvian cheese quality. Two types of semi-hard cheeses (Krievijas and Holandes) were selected for testing the quality of Latvian semi-hard cheeses in the beginning of 2008. Krievijas type cheese was selected from three different manufacturers, but Holandes type cheese - from five different manufacturers. Sensory properties such as flavour, structure and colour were measured using line scale method. Statistical analysis of obtained data showed differences between such assessed properties as colour (yellowness), texture (firmness), holes, flavour (acidity and bitterness) in Krievijas type cheese, and colour (yellowness), texture (firmness), flavour (saltiness) in Holandes type cheese.
显示更多 [+] 显示较少 [-]Nutritional changes in several potato varieties during heat treatment processes
2008
Murniece, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklina, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Galoburda, R., Latvia Univ. of Agriculture, Jelgava (Latvia)
Processing and cooking methods can greatly affect the nutritional value of fruits and vegetables including potatoes. In human nutrition potatoes before consumption are always prepared by several cooking methods and are one of the central components of warm meals. During treatment processes considerable changes in nutritional composition and nutritional quality of the product are induced. Hence the aim of the study was to determine the amount of basic nutrients (carbohydrate, fat and protein) as well as essential amino acids in five Latvian potato varieties prepared by the following heat treatment methods: baking in oven, shallow frying and deep fat frying and to compare the obtained results with recommended daily intake (RDI). Achieved results show significant differences in total carbohydrate amount within potato varieties (p=0.007) while within the type of heat treatments were no significance (p=0.065). Changes in fat content between heat treatment processes were considerable (p=0.000) whereas significance were discovered between control – pan fried, control – deep fat fried, baked in oven – pan fried, baked in oven – deep fat fried as well as pan fried – deep fat fried samples while no significance found among potato varieties (p=0.391). In protein amount neither within potato varieties nor between heat treatment processes significance was discovered, but the amount of essential amino acids significantly differs per each potato variety and type of heat treatment processes. Results on RDI per each nutrient group (fat, carbohydrates and protein) show significance on % RDI per each basic nutrient.
显示更多 [+] 显示较少 [-]Simulation of costs and benefits of supplementing milking cows with legumes during the dry season in two hillside regions of Nicaragua 全文
2008
Holmann, Federico J. | Tiemann, Tassilo T.
Objectives of this study were to compare costs and expected benefits of feed supplementation in cattle with alternative shrub legumes during the dry season using as a case study the hillsides of Central Nicaragua. The information used was gathered in a survey of 32 farms in the states of Boaco and Chontales in Central Nicaragua. The survey was designed to determine herd structure, land use patterns, milk and beef production, and use of inputs for animal nutrition, in order to estimate production, reproductive parameters and employment of family/contracted labor, as well as indicators of profitability of the alternatives under study. To calculate the economic return to the investment in alternative forages, a simulation model that applies optimization techniques through linear programming, implemented as a spreadsheet, was used to perform an ex ante evaluation of the costs and benefits of different land use alternatives and of interactions between technological components and biological productivity. The model compares the costs and benefits of the traditional feeding system versus an improved feeding system. The traditional system consists of grazing naturalized pastures (Hyparrhenia rufa) during the rainy season. In the dry season producers supplement the herd with small areas of king grass (Pennisetum spp.). The improved feeding system consists of establishing forage legumes for dry season feeding as a supplement to replace king grass during the dry season. Supplements to evaluate are the shrub legume Calliandra calothyrsus as partial replacement of the herbaceous high quality legume Vigna unguiculata, commonly known as Cowpea. Under the new feeding system, herd size can be increased by 60% due in part to the increase in stocking rate as well as to the increase in the quality of the diet offered with higher protein content. This increase in herd size raises both milk and beef output that generates an increase in farm income by 1.8 times more (i.e., from $1,314/farm/yr to $2,386). The economic return to family labor is increased by 20% to $ 5.26/day equivalent to 2.3 times higher than the local wage rate. The adoption of Vigna (Cowpea) after the harvest of maize/beans and a shrub legume as Calliandra to replace king grass seem to have the potential to significantly improve the productivity in smallholder farms. with the resulting increase in the economic return to family labor.
显示更多 [+] 显示较少 [-]Wool characteristics of Libyan Barbary sheep in north-eastern Libya: I. Fiber diameter and staple length 全文
2008
Akraim, F. | Milad, I.S. | Abdulkarim, A.A. | Ganem, M.
In this study wool characteristics of Libyan sheep in north-eastern Libya were investigated in a coastal region extended from El-Marj (32 25 N and 20 30 E) to Emsaad at the north-eastern border of the country (31 33N, 25 6 E). Twelve locations, one flock per flock were studied. Three sites have been sampled from each animal (Shoulder, mid-side and breech). Mean staple length and fiber diameter were 12.16cm and 38.43 µm respectively. In this study, staple length and fiber diameter didn’t significantly vary between locations studied. Sample site on the body of the animal significantly affect both staple length and fiber diameter, with breech position samples showed the shortest staple length and the thickest fiber diameter (P< 0.05). There was no difference between samples taken from mid-side or shoulder in all measured traits. Results of this study showed that Barbary sheep raised in the eastern part of the country characterized by a long staple and a large fiber diameter, and then confirmed the previous studies studies stated that this breed could be classed as a long carpet wool breed. Samples taken from mid-side position could be representative of Barbary sheep fleece
显示更多 [+] 显示较少 [-]Effect of live weight at slaughter on the carcass characteristics of intensively fattened Martinik sheep fed sugar cane supplemented with pea flour. 全文
2008
Alexandre, Gisèle | Coppry, Ode | Bocage, Bruno | Fleury, Jérôme | Archimède, Harry | Unité de Recherches Zootechniques (URZ) ; Institut National de la Recherche Agronomique (INRA) | Plateforme Tropicale d'Expérimentation sur l'Animal (PTEA) ; Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
International audience
显示更多 [+] 显示较少 [-]Comparaison des caractéristiques de production de la pintade locale (Meleagris numida) en station et dans le milieu villageois en zone soudano-guinéenne du Bénin | Comparison of local Guinea fowl (Meleagris numida) production characteristics in experimental station and rural area in soudano-guinean zone of Bénin 全文
2008
Dahouda, Mahamadou | Sènou, Marcel | Toleba, Soumanou Seibou | Boko, Cyrille Kadoito | Adandédjan, Jean-Claude | Hornick, Jean-Luc
peer reviewed | A survey on the production characteristics of guinea fowl (Meleagris numida) was carried out in the Borgou department located in the soudano-guinean zone North-Est of Benin. Chicks and reproductive groups were kept either on station under improved management conditions or in rural environment. In rural environment, the birds were divided in two groups. The birds pertaining to the first group were treated against parasitic diseases, whereas those in the second one (control group) received no treatment. Under station conditions, the feed conversion ratio and the daily weight gain were 8.8 and 5.7 g/day respectively. Mean body weight at six months of age were 1151g and 1085g for males and females, respectively. Sexual maturity was reached at 36 weeks of age. For mature hens kept on station, laying rate and the mean egg weight were 37.2% (65% at the peak) and 41.1g respectively. Smothering, stress and pricking were the major constraints to the cloistering of guinea fowl. In rural environment, the mean hatchability rate was 70%. Mortality rate and adult body weight were not significantly different between groups. Mortality rate observed in the rural environment was 50% for both treated or untreated birds. Apart from the parasitic affections, the main causes of mortality were the rain, the predators, the cold and the fragility of chicks. The mean body weight at six months of age is higher for the birds raised under village conditions in comparison to the birds kept on station.
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