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Results 3421 to 3450 of 4099:

Separation of low molecular weight rapeseed proteins by RP-HPLC-DAD - a short report

Agnieszka Kosińska, Uttam D. Chavan, Ryszard Amarowicz

Czech J. Food Sci., 2006, 24(1):41-44 | DOI: 10.17221/3292-CJFS

Low molecular weight proteins were extracted and isolated from rapeseed and analysed using the HPLC-DAD method. The separation of proteins and phenolic compounds was done on the reversed phase C18 column with a gradient of acetonitrile in water. The chromatogram was characterised by two peaks of low molecular weight proteins with the retention times of 19.92 and 23.24 min. Additional three main peaks of phenolic constituents were recorded on the chromatogram. One of them with maximum of UV spectrum at 328 nm was identified as sinapic acid derivatives.

Competition between triticale (Triticosecale Witt.) and field beans (Vicia faba var. minor L.) in additive intercrops

P. Sobkowicz

Plant Soil Environ., 2006, 52(2):47-54 | DOI: 10.17221/3345-PSE

In a microplot experiment conducted in 1999 and 2000 on light soil triticale and field beans were grown as sole crops and in the intercrop system. Two pure stand plant densities were established: 200 and 400 plants/m2 for triticale and 50 and 100 plants/m2 for field beans. Four possible intercropping combinations were obtained by adding densities of both crops. Triticale was a better competitor than field beans in all intercrops resulting in competitive balance index significantly greater than zero. The number of pods per plant of field beans was significantly reduced in all intercropping combinations compared to the pure stands, however quality of grain of the legume was unaffected by competition. Intercrop comprising 200 plants/m2 of triticale and 50 plants/m2 of field beans was most productive in the experiment but addition 50 more plants/m2 of the legume decreased significantly grain yield of intercrop by 16.2%. The results also show that effective triticale-field beans intercrop for light soil may be designed as additive one, based on 400 plants/m2 of triticale.

The influence of tillage on selected biological parameters

O. Mikanová, M. Javůrek, M. Vach, A. Markupová

Plant Soil Environ., 2006, 52(6):271-274 | DOI: 10.17221/3440-PSE

The influence of tillage (conventional and non-tillage) on selected soil microbial properties was studied. The experiment focused on tillage that was launched in Prague-Ruzyne in 1997. The experiment included the following variants: conventional tillage, protective tillage (without post harvest residues), protective tillage (with residue biomass - mulch), protective tillage (covered by pea crop residues for winter wheat, with fore crop). In the field experiment there were tested: enzymatic activities (activity of urease, dehydrogenase, arylsulfatase and invertase) and microbial biomass. The microbial biomass and soil microbial processes were affected by tillage. Our results show the positive influence of protection tillage on selected biological parameters, especially in variants where soil was supplied with organic matter.

Progression of Deoxynivalenol Concentrations in Spikes and Kernels of Winter Wheat Cultivars after Inoculation with Fusarium culmorum

Jana Chrpová, Václav Šíp, Eva Matějová, Světlana Sýkorová

Czech J. Genet. Plant Breed., 2006, 42(4):137-141 | DOI: 10.17221/3644-CJGPB

Progression of deoxynivalenol (DON) concentrations in spikes and kernels was studied in relation to Fusarium head blight (FHB) symptoms in five winter wheat cultivars, differing in resistance to FHB, after single floret inoculation with an aggressive isolate of Fusarium culmorum. After inoculation in field conditions the spikes were detached from the plant and kept in the greenhouse under controlled conditions. High concentrations of DON were detected in susceptible cultivars at an early stage of pathogenesis (7 days after inoculation). Over the whole examined 21-day period and also at maturity spikes contained more DON than kernels. While differences between cultivars in the accumulation of DON were highly expressed already 7 days after inoculation, differences in symptomatic reactions were not clear until day 21. Owing to the reported crucial role of DON at early stages of pathogenesis, the importance of appropriate timing of fungicide application is highly stressed.

Change of amino acid profile in Charolais cows' colostrum and transient milk during the first week post partum

R. Zándoki, J. Csapó, Z. Csapó-Kiss, I. Tábori, Z. Domokos, E. Szűcs, J. Tőzsér

Czech J. Anim. Sci., 2006, 51(9):375-382 | DOI: 10.17221/3954-CJAS

In this study the change in amino acid profile in cow's colostrum and transient milk during the first week after parturition was examined in a Hungarian Charolais herd. Experiments were carried out with n = 37 Charolais cows in the same herd in the spring (March-April) of two consecutive years (Experiment 1: 2002, n = 15; and Experiment 2: 2003, n = 22). Colostrum and milk samples were taken by hand milking immediately after delivery, and in 24, 48, 72, and 168 hours post partum. Amino acid contents (%) in samples were measured in milk protein with an automatic amino acid analyser. Data were processed by the software of SPSS.10 statistical program package. In the postpartal period, among essential amino acids significant increases were recorded in methionine, isoleucine, lysine, and phenylalanine, and among non-essential amino acids glutamic acid and proline increased significantly. Simultaneous decreases were recorded in valine, cysteine, aspartic acid, serine, glycine, and arginine. Inconsistent figures were determined for histidine, leucine, tyrosine, and alanine content between Experiment 1 and Experiment 2.

Granulometric study of Synferta N-22 and Synferta N-17

J. Krupička, B. Hanousek

Res. Agr. Eng., 2006, 52(4):152-155 | DOI: 10.17221/4892-RAE

Physical properties of commercial fertilizers play important role from precision application point of view. Granulometric evaluation is usually performed by sieve separation according ČSN 01 5030 standard. The main subject of this work is the presentation of separation results when vertical airflow is used.

Mycobacterium caprae infection in cattle and pigs on one family farm inCroatia: a case report

Z. Cvetnic, S. Spicic, V. Katalinic-Jankovic, S. Marjanovic, M. Obrovac, M. Benic, M. Mitak, I. Pavlik

Vet Med - Czech, 2006, 51(11):523-531 | DOI: 10.17221/5586-VETMED

An outbreak of tuberculosis among bovines and pigs caused by Mycobacterium caprae is described in this paper. After tuberculin skin tests with bovine purified protein derivates (PPD) six cattle and one sow, own by a small family farm, tested positive whilst three pigs were suspected in 2004. All animals were euthanised and checked for gross pathological lesions. Generalised lesions were found in five cattle and two sows; however one calf and two gilts had lesions that were localised in the submandibular lymph nodes. Mycobacteria were isolated from tissue samples of six cattle and four pigs. Mycobacterial isolates were identified using classical biochemical tests and molecular methods (PCR, GenoType MTBC) as M. caprae. Mycobacterial Interspersed Repetitive Unit (MIRU) typing of isolated mycobacteria showed an identical number of repeats in 12 different loci. Results of the research confirmed the domination of M. caprae among infected cattle in Croatia; however this paper was the first to confirm a case of M. caprae in pigs. The source of the infection was not found.

Morphological and physiological parameters of beech leaves (Fagus sylvatica L.) in research demonstration object Poľana

D. Hladká, I. Čaňová

J. For. Sci., 2005, 51(4):168-176 | DOI: 10.17221/4556-JFS

Observations of the beech assimilatory apparatus in different levels of a model tree were realised from 1993 to 1999 in a research demonstration plot situated in Poľana. Different observations of the natural ecosystem condition were carried out. A model beech tree was chosen and marked as No. 228 for the above-mentioned analyses. The different ecophysiological and morphological characteristics of beech leaves were analysed in three (or two) tree crown levels. The results confirmed significant differences in these characteristics in dependence on three crown levels of mature beech tree. The differences in the mentioned characteristics were also shown in the course of particular years of research. In this paper we have presented the results of analysed beech leaves, their average maximum length, width, their average area, thickness, chlorophyll fluorescence during the research period.

Frost cracks and their effect on the stability of birch stands in the Krušné hory Mts.

E. Kula, I. Buchta, P. Stránský

J. For. Sci., 2006, 52(8):348-356 | DOI: 10.17221/4517-JFS

Frost cracks which originated in birch due to bending during long-term icing in winter 1995/1996 became the place of entrance for the attack of birch stems by Piptoporus betulinus (Bull. ex Fr.) Karst. and subsequently for one of the causes of birch stand disintegration in the Krušné hory Mts. The hypothesis is substantiated on the basis of regularities of the frost crack dispersion in the stem profile, frequency of occurrence related to the stand age, altitude and cardinal points. The number of frost cracks increased with the transect profile altitude 700-850 m. One crack on the birch stem predominated (73%) while the higher number of frost cracks occurred at altitudes > 800 m. In stands younger than 20 years, frost crack damage was higher (34-47%) than in older stands (14%). Frost cracks occurred in the lower part of stems with the highest bending stress.

Determinants of economic results of the selected agricultural enterprises in mountain and sub-mountain areas in South Bohemia

V. Krutina, I. Faltová Leitmanová

Agric. Econ. - Czech, 2005, 51(3):117-122 | DOI: 10.17221/5084-AGRICECON

The evaluation of conditions for farming of agricultural enterprises in sub-mountain and mountain areas of South Bohemia results from the analyses of material and physical indicators and characteristics. The analyses of farmland fund and its exploitation, plant and animal structure and physical results converted into money enable to identify and assess the state and development of relations which affect the economic results of these agricultural enterprises.

Collective bargaining and industrial relations in agriculture - the case of Slovakia

S. Buchta

Agric. Econ. - Czech, 2006, 52(1):45-50 | DOI: 10.17221/4995-AGRICECON

Trend analysis of revenues and costs within the chosen commodities under the conditions of organic agriculture

J. Jánský, I. Živělová, J. Poláčková, J. Boudný, R. Redlichová

Agric. Econ. - Czech, 2006, 52(9):436-444 | DOI: 10.17221/5047-AGRICECON

This paper deals with the analysis of the trends in costs and revenues of selected agricultural products grown and bred under the conditions of organic agriculture. The analysis of the trends in revenues and costs is performed for the cattle breeding, beef cows and for the plant production of spelt, oat and potatoes. Costs are evaluated in the relationship with the direct and indirect costs. Revenues are traced with the help of per hectare yield, efficiency and market prices. Data of the selected file of the organically farming companies for the controlled commodities are compared with the same commodities of the selected file of the conventionally farming companies worked by the Research Institute of Agricultural Economics (RIAE) in Prague.

Survey of incidence of bunts (Tilletia caries and Tilletia controversa) in the Czech Republic and susceptibility of winter wheat cultivars

Marie Váňová, Pavel Matušinský, Jaroslav Benada

Plant Protect. Sci., 2006, 42(1):21-25 | DOI: 10.17221/2692-PPS

Bunts (caused by Tilletia caries and T. controversa) belong to very important diseases of winter wheat because contaminated commodities (seeds, foods and feeds) affect the marketability of the crop on both domestic and export markets. They can be relatively easily controlled by chemical seed treatments. Due to the availability of effective chemical control, the reaction of wheat cultivars to bunts has so far not been an important trait for plant breeders in some areas of the world. However, if synthetic chemicals are not allowed, like in organic farming, untreated seed may quickly lead to a build-up of bunt to levels that render the crop unmarketable. The use of wheat cultivars partially or fully resistant to bunts could greatly contribute to ease the bunt problem. The reaction of winter wheat cultivars was evaluated in field tests. Seeds of winter wheat were inoculated with teliospores of T. caries. The reaction to T. controversa was studied under heavy natural infestation with spores in the soil. With T. caries, the heaviest infection was found in cvs Drifter and Ebi, while cvs Nela, Brea and Samanta had the lowest. The average level of infection with T. controversa was higher than that of T. caries. The cvs Niagara, Brea and Versailles had significantly lower numbers of bunt ears of T. controversa in 2002. The incidence of both bunts in grain samples that had not been cleaned and sorted after harvest was monitored for 4 years. A total of 1 058 samples collected from various locations in the Czech Republic were analysed for the presence of bunt spores and the species determined. The investigation demonstrated a rather widespread occurrence of bunts across the Czech Republic, with T. controversa being more frequent.

Soybean (Glycine max) seed growth characteristics in response to light enrichment and shading

X. Liu, Herbert S.J., K. Baath, A.M. Hashemi

Plant Soil Environ., 2006, 52(4):178-185 | DOI: 10.17221/3363-PSE

Seeds are the primary sinks for photosynthates during reproductive growth. Variation in light intercepted during and after seed initiation has been found a major environmental determinant of soybean [Glycine max(L.) Merrill] seed size. We investigated the influence of light enrichment and shading on seed growth rate, effective filling, cotyledon cell number, cell volume and endogenousABA concentrations of cotyledons/testas during seed filling of soybean. Evans, an indeterminate Group 0 soybean, was subjected to light reduction and enrichment treatments from the beginning of pod formation until final harvest for two years inMassachusetts. Higher rates of seed growth, greater seed dry weight, and higher cotyledon cell number were all observed with light enrichment. There was a reduction in seed growth rate and cotyledon cell number, along with a significant lowering of endogenousABA levels in testa and cotyledon with shade. The level ofABAin cotyledon during seed development was significantly correlated with seed growth rates only under shade treatments. Both the growth rates and seed filling duration were influenced by variation in light interception by the soybean canopy. The effects of varying light treatment on seed size, within one genotype, were most likely due to the differences in seed growth rate and cotyledon cell number.

Breeding Barley for Multiple Disease Resistance in the Upper MidwestRegion of the USA

Brian J. Steffenson, Kevin P. Smith

Czech J. Genet. Plant Breed., 2006, 42(3):79-86 | DOI: 10.17221/3646-CJGPB

Effect of long-term storage on induced photon emission of boar spermatozoa

P. Gogol, B. Szczęśniak-Fabiańczyk

Czech J. Anim. Sci., 2006, 51(2):61-65 | DOI: 10.17221/3910-CJAS

Ultraweak photon emission measurements were found to be a useful tool for investigating the influence of stress factors on cells. In the present study, induced photon emission of boar spermatozoa was investigated using a luminometer during a 12-day storage at 15°C in Biosolwens extender. It was shown that the day of storage had a significant effect on some photon emission parameters. During storage, a significant increase in the Integral, Peak max. and Slope max. parameters and a decline in the T.-half (fall) parameter were observed. A significant correlation was observed between photon emission parameters and sperm motility. In conclusion, the results of the present study indicate that the measurement of induced photon emission can be an alternative, sensitive and relatively simple method for assessing the effect of preservation on oxidative damage to boar spermatozoa.

The use of extruded chickpeas in diets for growing-finishing pigs

V. Christodoulou, V.A. Bampidis, E. Sossidou, J. Ambrosiadis, B. Hučko, C. Iliadis, A. Kodeš

Czech J. Anim. Sci., 2006, 51(8):334-342 | DOI: 10.17221/3947-CJAS

The effect of partial and total replacement of soybean meal (SBM) with extruded chickpeas (Cicer arietinum L.) and partial replacement of SBM with raw chickpeas on pig growth and carcass characteristics was determined in a 17 week experiment. Sixty growing-finishing pigs were allocated to five dietary treatments: CKP0, ECKP100, ECKP200, ECKP300 and CKP100 of 12 animals each, and received a diet ad libitum. The diet for CKP0 treatment had no chickpeas (control), while those for treatments ECKP100, ECKP200 and ECKP300 included 100, 200 and 300 kg/t of extruded (at 120°C for 20 s) chickpeas, respectively, and for treatment CKP100 it included 100 kg/t of raw chickpeas. Body weight (BW) gain linearly increased (P < 0.05) and feed conversion ratio (FCR) linearly decreased (P < 0.05) with the inclusion of increasing levels of extruded chickpeas during the growing period. However, in both the growing and finishing period, there were no differences between extruded chickpea inclusion treatments in final BW, BW gain, daily feed consumption (DFC), FCR, and carcass yield traits. Partial replacement of SBM with raw chickpeas negatively affected (P < 0.05) BW gain and DFC during the finishing period. Extrusion offers a practical method for the heat processing of chickpeas for use in pig diets. Thus, extruded chickpeas can be used as an alternative protein source to SBM at inclusion levels up to 300 kg/t of diet.

Study of some characteristics of vegetable pepper varieties

M. Valšíková, J. Králová, Š. Barkoci

Hort. Sci. (Prague), 2006, 33(4):153-157 | DOI: 10.17221/3755-HORTSCI

In three test years an assortment of 15 varieties of vegetable pepper (Capsicum annuum L.) were grown in field conditions to study experimentally some of their morphological and biological properties. Mean plant height ranged from 435.7 mm (cv. Lastočka) to 636.7 mm (cv. Srbská). The smallest fruits had cultivars Čerešňová and Kecskeszarv with the weight of 4.86 g and 17.68 g. Average weight was the highest at varieties Pola kapia (92.23 g) and Melišor (91.92 g). The biggest length of mature leaves over 100 mm was measured at varieties Dolmy, Podarok Moldavy and Tuba; the smallest leaves according to length and width had variety Čerešňová. The mean vitamin C content in fruits about 2,000 mg/kg at green mature stage was found in cv. Bohatýr, Čerešňová and Podarok Moldavy. The highest vitamin C content in red fruits was analyzed at cv. Čerešňová (2,551.0 mg/kg) and Lastočka (2,422.2 mg/kg). Other observed characteristics were colour, shape and taste of fruits, colour of leaves and fruit wall thickness.

Effects of the thickness of rotary-cut veneers on properties of plywood sheets. Part 2. Physical and mechanical properties of plywood materials

J. Hrázský, P. Král

J. For. Sci., 2006, 52(3):118-129 | DOI: 10.17221/4493-JFS

The second part of the paper summarizes results of an institutional research aimed at the determination of physical and mechanical properties of different sets of plywood sheets pressed under different conditions. The first part dealt with the determination of compressibility or values of decreasing the thickness of pressed plywood sheets. In this second part, results are summarized of the analysis of physical and mechanical properties of the set of whole-beech plywood sheets of the nominal thickness of veneers amounting to 1.5 mm. The plywood sheets were manufactured as seven-ply and urea-formaldehyde resin DUKOL S was used for their production. The sheets were pressed using a pressure of 1.5 and 1.7 MPa. Following parameters were analyzed: moisture, density, bending strength, MOE in bending and shear strength.

Status of soil acidification in North America

M. E. Fenn, T. G. Huntington, S. B. Mclaughlin, C. Eagar, A. Gomez, R. B. Cook

J. For. Sci., 2006, 52(20):S3-S13 | DOI: 10.17221/10152-JFS

Forest soil acidification and depletion of nutrient cations have been reported for several forested regions in North America, predominantly in the eastern United States, including the northeast and in the central Appalachians, but also in parts of southeastern Canada and the southern U.S. Continuing regional inputs of nitrogen and sulfur are of concern because of leaching of base cations, increased availability of soil Al, and the accumulation and ultimate transmission of acidity from forest soils to streams. Losses of calcium from forest soils and forested watersheds have now been documented as a sensitive early indicator and a functionally significant response to acid deposition for a wide range of forest soils in North America. For red spruce, a clear link has been established between acidic deposition, alterations in calcium and aluminum supplies and increased sensitivity to winter injury. Cation depletion appears to contribute to sugar maple decline on some soils, specifically the high mortality rates observed in northern Pennsylvania over the last decade. While responses to liming have not been systematically examined in North America, in a study in Pennsylvania, restoring basic cations through liming increased basal area growth of sugar maple and levels of calcium and magnesium in soil and foliage. In the San Bernardino Mountains in southern California near the west coast, the pH of the A horizon has declined by at least 2 pH units (to pH 4.0-4.3) over the past 30 years, with no detrimental effects on bole growth; presumably, because of the Mediterranean climate, base cation pools are still high and not limiting for plant growth.

Regional differentiations of rural villages in the Czech Republic

Z. Bednaříková, Z. Trávníček, V. Vávra

Agric. Econ. - Czech, 2006, 52(6):273-280 | DOI: 10.17221/5024-AGRICECON

Rural villages are the sole subjects in rural area which integrate all elements acting in the rural area to one functional whole. They can be therefore taken as the pivotal element of rural development. The research was done in 2004 and was based on the search for rural villages' characteristics and exploration of the elements of regional differentiation. The project results from the presumption of difference between the rural villages given by their size, location in specific areas or on exposed roads, distance from civic centers etc. It is supposed that these characteristics have specific and significant connections with such phenomenon as the level of unemployment, the level of civic and technical facilities in villages, the activity of inhabitants and the village itself, etc. The challenge was to define problem characteristics of rural areas, which mirror significant regional differences, structure and interconnectedness of these differences and their importance for future regional development. Interdependence of particular indicators was explored by statistical evaluation.

Determination of selected parameters of quality of the dairy products by NIR spectroscopy

Jana Růžičková, Květoslava Šustová

Czech J. Food Sci., 2006, 24(6):255-260 | DOI: 10.17221/3322-CJFS

The possibility of the application of near-infrared spectroscopy to the analysis of the selected parameters of quality of the dairy products was followed. The contents of solids and fat, as well as pH in yoghurts (also the titrable acidity), milk semolina, and milk rice were determined. The samples were analysed by reference methods and by FT NIR spectroscope at integrating sphere within reflectance mode in the wavelength range of 10 000-4 000 cm-1 with 100 scans. To develop the calibration model for the components examined, the partial least squares (PLS) was used and this model was validated by full cross validation. The highest correlation coefficients were found with yoghurt: 0.998 (solids), 0.989 (fat), 0.875 (pH) and 0.989 (titrable acidity), with milk semolina: 0.967 (solids), 0.983 (fat) and 0.992 (pH), and with milk rice: 0.987 (solids), 0.990 (fat) and 0.852 (pH). The results of this study showed the availability of NIR spectroscopy for a quick and non-destructive analysis of the dairy products.

Powdery Mildew Resistance of Foreign Spring Barley Varieties in Czech Official Trials

Antonín Dreiseitl

Czech J. Genet. Plant Breed., 2006, 42(1):1-8 | DOI: 10.17221/3656-CJGPB

Efficacy of some fungicides in Tilletia tritici control

S. Rajkovi, N. Dolovac

Czech J. Genet. Plant Breed., 2006, 42(10):51-55 | DOI: 10.17221/6232-CJGPB

The use of performance test parameters for selection of gilts before their placement into breeding

N. Kernerová, J. Václavovský, V. Matoušek, Z. Hanyková

Czech J. Anim. Sci., 2006, 51(6):253-261 | DOI: 10.17221/3937-CJAS

The objectives of the paper were to evaluate carcass value in reared gilts on the basis of carcass analysis during the station test of purebred progeny of pigs and ultrasonically with Sonomark-100 or Piglog-105 instruments in the framework of valid methodology for performance testing, and to verify a pos-sibility of prediction of backfat thickness and/or average daily weight gain since birth and lean meat content of gilts as the elements of objectification for the evaluation of their body condition. In total 54 gilts of two breeds were evaluated: the dam breed Czech Large White and the sire breed Czech Large White - sire line. Four-parameter Richards function was used for growth evaluation. The regression function y = 63.870 - 0.447 bt1 - 0.510 bt2 + 0.128 MLLT was applied in ultrasonic instruments for the calculation of lean meat content. We calculated linear regression functions for the conversion of performance testing parameters (gain from birth, average backfat thickness and lean meat content) from live weight on the day of measurement per live weight declared during selections in gilts.

Responses of milk urea nitrogen content to dietary crude protein level and degradability in lactatingHolsteindairy cows

S.W. Zhai, J.X. Liu, Y.M. WU, J.A. YE, Y.N. XU

Czech J. Anim. Sci., 2006, 51(12):518-522 | DOI: 10.17221/3972-CJAS

Two experiments were conducted to investigate the effects of dietary crude protein level and degradability on milk urea nitrogen (MUN) content. In experiment 1, twelve multiparous lactating cows averaging 176 days in milk were divided according to DIM and milk production into three 4 × 4 Latin squares with four 2-week periods. Cows were fed four diets with different crude protein levels (13.0, 14.0, 15.0, and 16.0%, DM basis) with isocaloric, respectively. Crude protein levels had a low effect on milk yield and composition (P > 0.05), but a significant effect on MUN content. There were significant differences in the MUN content of cows fed either of the two diets (P < 0.01). In experiment 2, fifteen multiparous Holstein dairy cows averaging 91 days in milk were classified according to DIM and milk production into five 3 × 3 Latin squares with three 3-week periods. Cows were fed one of the three isocaloric and isonitrogenous diets with RUP being 30.8%, 36.2%, and 41.6% (CP basis), respectively. Milk yield, milk composition, and MUN content were not significantly affected by protein degradability, and there were no significant differences between any two dietary treatments (P > 0.05). These results indicated that MUN might be used as a parameter to monitor the change in dietary protein levels.

Collection of oocytes from donors in the growth phase of follicular development can enhance the production of bovine embryos for cryopreservation

M. Machatkova, K. Hanzalova, J. Horakova, Z. Reckova, P. Hulinska

Vet Med - Czech, 2006, 51(5):232-238 | DOI: 10.17221/5542-VETMED

The present study was designed to compare the efficiency of bovine embryo production for cryopreservation between oocytes collected from donors in the growth phase of follicular development (GPFD) and those recovered from donors in the undefined phase (UPFD). Cyclic cows, Czech Siemental or Holstein dairy breeds, 4-6 years of age, slaughtered at the local abbatoir were used. They were divided into two groups based on ovarian morphology: I. GPFD donors with ovaries corresponding to the growth phase of the first follicular wave (estrus cycle days 3-4; n = 52), and II. UPFD donors with ovaries in any other phase of follicular development (undefined estrus cycle days; n = 89). A total of 3 771 oocytes were collected and 1 134 embryos were prepared as two separate populations by standard protocol. In total 352 excellent or good quality embryos at the early, advanced or expanded blastocyst stage from both donor groups were pooled and used for cryotolerance assessment. They were frozen on day 7 (D7) or day 8 (D8) after fertilization by the standard procedure. After thawing, the embryos were cultured for 72 h to the hatching stage. The percentages of both D7 embryos and advanced blastocysts were significantly higher (P ≤ 0.01) for oocytes collected from GPFD donors than for oocytes collected from UPFD donors (33.7 vs 28.6% and 43.0 vs 29.5%, respectively). The percentages of excellent or good quality embryos obtained from both D7 embryos and fertilized oocytes were significantly higher (P ≤ 0.01) for oocytes collected from GPFD donors than for oocytes collected from UPFD donors (63.6 vs 49.4% and 21.4 vs 14.1%, respectively). The post-thaw survival rates were significantly higher (P ≤ 0.01) for D7 than D8 embryos (80.4 vs 66.3%). In relation to the developmental stage, the development and hatching rates were significantly higher (P ≤ 0.01) for D7 than D8 early blastocysts (75.0 vs 41.2% and 50.0 vs 5.9%, respectively) and for D7 than D8 advanced blastocysts, (73.7 vs 57.1 and 52.6 vs 28.6%, respectively). No differences were found between D7 and D8 expanded blastocysts after freezing-thawing. In conclusion, the collection of oocytes from donors in the growth phase positively influenced the in vitro production of bovine embryos for cryopreservation. The development of embryos produced with oocytes from GPFD donor group was accelerated and more excellent and good advanced blastocysts with greater cryotolerance were produced on day 7 after fertilization, as compared to embryos produced with oocytes from the UPFD donor group.

Spontaneous infiltration of broadleaved species into a spruce monoculture left without tending

P. Jelínek, P. Kantor

J. For. Sci., 2006, 52(1):37-43 | DOI: 10.17221/4485-JFS

An experimental stand was established as a monoculture by planting Norway spruce on a clear-felled area in 1925. In 1958, a research thinning experiment was established there. Control plots and the study of their development without anthropic interventions are of interest in particular. The spruce monoculture nearly disintegrated and the stand-forming role was taken over by species which occurred there originally as admixed ones. The stand became sparser and it was associated with the spontaneous regeneration of broadleaves. Out of the eight control plots three plots were selected differing significantly in stocking and extent of natural regeneration. The development of regeneration was studied in detail on these plots. The undergrowth consisted of 24 woody species in a total number of 6,000 individuals per hectare and about two thirds of them belonged to trees. The results of the study show a possibility to convert a spruce monoculture to a broadleaved commercial forest using the spontaneous regeneration of trees.

Regional classification of the Czech Republic, based on the production orientation of agricultural enterprises

F. Střeleček, J. Lososová

Agric. Econ. - Czech, 2005, 51(10):435-451 | DOI: 10.17221/5141-AGRICECON

ThearticledescribesthelayoutofplantproductionandlivestockdensityintheCzechRepublicin2003 according to a sample survey of the Czech Statistical Office.Theproductionorientationof agriculturalenterprisesis definedas a small amount of market products that represent the predominant part of revenues. Grain crops, pork meat, milk and non-food crops represent the production orientation of Czech agriculture. Thesecommoditiesrepresentmorethan70%oftotal agricultural production in the Czech Republic. In this article, the authors have attempted to definearegionalclassification according to production orientation of agricultural enterprises and intensity of agricultural production.

The sensitivity of flower bud thrips, Megalurothrips sjostedti Trybom (Thysanoptera: Thripidae), on cowpea to three concentrations and spraying schedules of Piper guineense Schum. & Thonn. extracts

Alphonsus Mbonu Oparaeke

Plant Protect. Sci., 2006, 42(3):106-111 | DOI: 10.17221/2757-PPS

The extracts of pods of West African black pepper, Piper guineense, at 5, 10 and 20% (w/v), were applied at two, four and six weekly schedules to control the legume flower bud thrips, Megalurothrips sjostedti on flowers of cowpea, Vigna unguiculata. The trials were conducted for 2 years under rain fed conditions in the northern Guinea savanna region of Nigeria. The results showed that the M. sjostedti population was significantly controlled on treated plots compared with the untreated check in both years. The extracts at the 20 and 10% rates and with six or four weekly applications significantly (P < 0.05) reduced thrips pressure on cowpea flowers, were better than the 5% extract at all spraying schedules, and had the same efficacy as the synthetic insecticide treatment. Pod density per plant was significantly higher (P < 0.05) on plots treated with the 20% extract at six or four weekly applications compared to other extract rates and was similar to that of the synthetic insecticide treatment. Thus, the extracts could be a good alternative to the synthetic insecticides on organically managed farms as well as on farms of limited resource farmers in the tropics and subtropics.

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