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1.
Two experiments in which early-weaned lambs (4–7 and 5–9 weeks of age) continuously grazed a perennial ryegrass-white clover sward are described. In both experiments groups of lambs were offered a proprietary concentrate ad libitum, 2/3 or 1/3 of ad libitum allowance, or no concentrate. Mean daily gains over 56 days in Experiment 1 increased from 88 g without concentrate to 275 g with ad libitum concentrate allowance; the range in daily gains over 71 days in Experiment 2 was 201 g to 253 g respectively. In both experiments mean faecal OM output from herbage decreased as concentrate OM intake increased.  相似文献   

2.
Windrowed pyrethrum stems were air dried under a range of storage conditions to examine whether the current commercial practice of drying crop material is conducive to pyrethrins’ degradation. Crop material was stored for up to 12 days in a commercial windrow, a shed receiving indirect light or a dark, 5 °C cool-room. Analysis of pyrethrins extracted from flowers of all treatments demonstrated that pyrethrins were not degrading in windrowed crops, plant material stored in the shed or in the 5 °C cool-room. The small differences obtained in pyrethrins content among the treatments can be explained by the natural variation in pyrethrins content of pyrethrum crops. The observation that the achenes were unchanged during this drying period supported the pyrethrins analysis. These results demonstrate that pyrethrins in planta do not degrade as rapidly as extracted pyrethrins.  相似文献   

3.
Megacopta cribraria (Hemiptera: Plataspidae) continually outbreaks due to suitable photoperiod in recent years. Effect of photoperiod on growth, development and reproduction of M. cribraria were assessed in this study. Results indicated that developmental duration, nutrient accumulation efficiency, and adult fecundity of M. cribraria were significantly different under 6 photoperiodical conditions. Developmental duration of nymph stage gradually tended to be shorter as day time increase. Body weights of 5th instar nymphs for 16 h and 4 h day time photoperiods were 5.2 mg and 4.6 mg, respectively. Moreover, longevity of adults tended to be longer as day time increase. However, for the short day photoperiod (4 L:20 D and 8 L:16 D), population showed no reproductive behaviors. Index of population trend increased with photoperiod extension and adults showed stronger reproductive capacity and longer longevity. This research identified the favorable photoperiodical conditions before outbreak. It may provided reference for ecological adaptability of M. cribraria, and contribute to the scientific basis for forecasting and controlling of M. cribraria.  相似文献   

4.
A perennial ryegrass sward was cut at a leafy stage of growth and harvested with different harvesters to produce silages differing in chop length to evaluate the effect of silage chop length on silage intake and on the performance of store Iambs when silage was fed as the sole diet. The silage was harvested in late May either as long silage (L), single-chopped (S). double-chopped (D). long precision-chopped (LP) or medium precision-chopped (MP) silage with (he appropriate machinery. The silages were treated with formic acid at 2.5 1 t?1. were well preserved (pH 3.7–3.8) and were of high dry-matter digestibility [749–810 g DMD kg?1 dry-matter (DM)]. The silages were fed ad libitum as the sole diet to Suffolk crossbred store lambs over a period of 11 weeks. Silage intake and lamb performance progressively increased as silage chop length declined from 32.4 cm (L) to 6.8 cm (MP). Silage intakes were 572, 661, 750, 893 and 1129 (± 21) g DM d?1 for silages L, S, D, LP and MP respectively. The corresponding daily liveweight gains were -3, 40, 53, 85 and 151 (± 7.6) g d?l. Similar increases in empty body weight gain and carcass weight gain were obtained as silage chop length declined. Rumen retention time (RRT), estimated from the rumen contents of the lambs at slaughter and their silage intake in the week before slaughter, was much shorter for silages LP and MP compared with silages L or S. Silage intake was negatively related to RRT(b= -24.5 ± 6.1 gDM h?l RRT). The results of this study showed that high intakes of grass silage and liveweight gains were achieved when grass was cut at a leafy stage of growth and harvested with a precision-chop harvester set to produce a moderate chop length (7 cm). The feeding of long or flail-chopped silages resulted in lower intakes and lower liveweight gains.  相似文献   

5.
Two experiments were carried out with grass silages cut at a leafy (Experiment 1) and a more mature (Experiment 2) stage of growth to evaluate the effect of wilting and chop length on silage intake and performance of store lambs. In each experiment, the herbage was cut with a rotary mower and was either ensiled within 24 h as unwilled silage (U) or wilted for 1–3 d (W). Each silage type was harvested with either a double-chop harvester (D) or a precision-chop harvester (P). All silages were treated with formic acid at 3 1 t?1 and were well preserved. The silages were fed ad libitum to Suffolk crossbred store lambs (twenty-four lambs per treatment) without any supplement over a period of 8 or 9 weeks. Wilting of the silages had little effect on silage intake (797 vs. 809g dry matter (DM) d?1) or on lamb performance in Experiment 1. In Experiment 2, wilting of the D silage increased silage DM intake (589 vs. 534 g DM d?1; +10%) and reduced the extent of liveweight losses. Wilting of the P silage reduced silage intake (770 vs. 791g DM d?1; -3%) and reduced liveweight gains. In Experiment 1 intakes of the D silages were 650–667g DM d?1 and just maintained lamb live weights. Intakes of the P silages were 39–49% higher than the D silages (927–968 g DM d?1) and increased liveweight gains. In Experiment 2 intakes of the D silages were 534–589 g DM d?1 and resulted in a loss in lamb live weight. Precision-chopping increased silage intakes by 31–48% (770–791 DM d?1)in Experiment 2 and improved lamb liveweight gains. Lamb performance was higher on the UP silage than on the WP silage. The rumen retention lime (RRT), estimated from the rumen contents of the lambs at slaughter and their silage intake before slaughter, was much shorter for the lambs fed on the P silages (12.6–20.6 h) than those fed on the D silages (21.4–29.3 h) in each experiment. Silage intake and liveweight gain were positively related to silage in vivo DM digestibility (DMD), whereas RRT was negatively related to DMD. However, there were distinct differences between the P and D silages in the elevation and, to a lesser extent, in the slope of the regression lines, indicating that intake of D silage was limited by factors other than the digestibility of the silage The results of this study show that the chop length of grass silage had a far greater effect on intake and on lamb performance than silage digestibility, whereas wilting had little or no effect.  相似文献   

6.
This study reports an experimental investigation on the effect of softeners, crosslinking conditions, and laundering on the comfort related and low stress mechanical properties of cotton fabrics with different weave constructions. Softeners with different chemical natures, in conjunction with the crosslinking agent and catalyst, were padded onto the cotton fabrics of three types of weave constructions, viz. plain, twill, and a newly developed plant-structured weave design. Two crosslinking conditions, namely dry and moist curing conditions, were compared. Scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscope were used to visualize and quantify the morphological and chemical changes on fabrics. The experimental results showed that the dry-crosslinking condition is preferable to achieve better comfort and easy-care properties, while moist-crosslinking condition is a better choice when strength-related properties are the main requirement. The study further showed that silicone elastomer softener can be applied to improve fabric strength whereas micro-emulsion of functional amino-polysiloxane plus emulsion containing polyalkylene is beneficial for comfort characteristic. The plant-structured cotton fabric finished in the dry-crosslinking condition with softener in nano-emulsion form can result in superb water absorption, excellent air permeability, good handle, acceptable strength, and improved easycare property.  相似文献   

7.
Early-weaned lambs were offered rations of conventional concentrate, dried grass and dried white clover pellets ad libitum for 52 days. In vivo OM digestibility coefficients of concentrate, grass and clover were 80.0, 53.4 and 66.6% respectively. Dry matter intake of dried grass was similar to that of concentrates but supported significantly lower (P < 0.001) daily gains (0.18 kg). Supplementation of dried grass with an equal proportion of dried clover significantly increased (P <0.05) DM and DOM intake and daily gains. Daily gains by lambs offered the 1:1 grass:clover diet (0.29 kg) were similar to gains by lambs offered either dried clover (0.30 kg) or concentrates (0.30 kg).  相似文献   

8.
《Crop Protection》1987,6(1):3-6
The sub-lethal effects of the formamidine insecticide chlordimeform on feeding and reproduction in the noctuid moth, Spodoptera littoralis, have been examined. By measuring changes in larval weight, chlordimeform hydrochloride was found to reduce food consumption significantly (by 25–64%) in fifth-instar larvae during a 48h period when incorporated at a rate of 0·1–10mg/g of artificial diet. Although no mortality was observed during larval feeding, considerable mortality occurred during pupation and subsequent emergence of the adult from the pupae. The compound also significantly reduced larval feeding by 22–28% compared with the control, when topically applied to fifth-instar larvae. Egg laying in female moths was reduced by at least 88% when chlordimeform was topically applied at a concentration of 1 or 10 μg/moth. Disruption of various components of normal egg-laying behaviour was also observed. The results are discussed in relation to recent evidence that, in addition to a direct killing action, chlordimeform induces abnormal changes in insect behaviour, especially during critical points in the life cycle, which may contribute to the protection of plants from insect attack.  相似文献   

9.
The aim of study was, comparison of effects of Metoclopramide and Dropridol associated with Dexamethasone on prevalence of nausea and vomiting after operation was considered. In this study 160 patients ASA physical status I were divided into two groups. In both groups, premedication and induction of anesthesia were given equally according to weight. To the first group, Metoclopramide associated with Dexamethasone and to the second group, Dropridol associated with Dexamethasone was ordered. At the end of the operation, after removing tracheal tube, prevalence of nausea and vomiting in both groups was considered after 2 h and results were analyzed with t-test and Chi-square. Ratio of nausea and vomiting after operation in the first group was 24% and in the second 8%. So results show that prevalence of nausea and vomiting in the second group was considerably lower than the first group (p < 0.004). According to the results of this study our conclusion, Dropridol with dexamethasone given at the before of general anesthesia was more effective in decreasing the prevalence of nausea and vomiting in patients compared with metoclopramide with dexamethasone.  相似文献   

10.
提取条件对大豆7S和11S球蛋白凝胶性的影响   总被引:1,自引:0,他引:1  
以低温脱脂大豆粕为原料,采用碱溶酸沉法浸提7S和11S球蛋白,用凝胶特性来评价提取条件对7S和11S球蛋白的影响。研究表明,提取7S和11S球蛋白时,浸提时间、浸提温度、pH值以及静置条件对蛋白质的结构均有一定的影响。通过质构仪进行物性测定进而分析蛋白质凝胶特性,得到了在浸提温度为45℃、浸提时间为40 min、11S球蛋白的酸沉pH值为6.4、7S球蛋白的酸沉pH值为4.7、4℃静置的条件下,7S和11S球蛋白产生的凝胶其硬度和弹性均处于较佳的状态,扩大了其在食品中的可应用性。  相似文献   

11.
Masham ewes, stocked at 20 ewes ha−1, reared twins at pasture in 1979 and 1980 and were rotationally grazed around six paddocks. There were three lengths of grazing cycle (18, 30 or 42 d) and the ewes at pasture were either offered silage ad libitum (S) for 8 weeks of lactation or they were not supplemented with silage (N). By feeding silage, S ewes and lambs moved into greater herbage masses (3735 u. 3390 kg organic matter (OM) ha−1), but there was little effect on net herbage accumulation (10.5 v. 10.0 t OM ha−1) and herbage intakes per ewe were similar (2.31 v . 2.27 kg OM d−1) over the 7-month grazing season. During the period of silage supplementation, total intake was 19% higher for S than N ewes, lamb growth rates were slightly higher (280 v . 273 g d−1) and the ewes lost less weight (−78 v −96 g d−1).
For 18-, 30- and 42-d grazing cycles respectively the herbage masses before grazing were 2825, 3620 and 4240 kg OM ha−1; net herbage accumulations were 9.8, 10.4 and 10.6 t OM ha−1; mean daily herbage intakes by each unit (ewe+lambs) were 2.22, 2.35 and 2.30 kg OM and lamb growth rates from birth to weaning at 20 weeks were 205, 204 and 204 g d−1.
Frequent grazing of relatively light herbage masses or infrequent defoliation of heavier herbage masses made little difference to sward or animal performance. It is concluded that, at this stocking rate, different grazing cycles of 18, 30 or 42 d do not affect the performance of lactating ewes.  相似文献   

12.
Pearl millet was decorticated to obtain a bran rich and endosperm rich fraction. The two fractions were soaked in solutions with varying pH. Pearl millet grains were germinated and steamed followed by decortication to obtain two fractions. It was observed that bran rich fractions contained high concentrations of iron, zinc, polyphenols, phytic acid, fibre and flavonoids. Soaking for short duration of 3 h did not result in major mineral losses but decreased the inhibitory factors which depended on the pH. Alkaline soaking decreased flavonoid content by 62.7% in the endosperm rich fraction, while acidic soaking decreased phytic acid content to the maximum in the bran rich fraction. Combination of treatments like germination and heat decreased the phytate content to the maximum in the endosperm rich fraction. Acidic conditions improved zinc bioaccessibility in the bran rich fraction (35%) and iron bioaccessibility (2.5%) in the endosperm rich fraction. Bran rich fraction from germinated grain also had enhanced bioaccessibility of both the minerals but comparatively lesser when compared to soaking under acidic conditions. Soaking the grain components under slightly less than neutral conditions also decreased some of the inhibitory factors and improved the zinc bioaccessibility to some extent in the bran rich fraction.  相似文献   

13.
Effect of catalytic conditions on the synthesis of new aconitate esters   总被引:1,自引:0,他引:1  
Sugar cane is a crop which generates large amounts of biomass and a juice rich in high-value natural molecules. After extracting sugar from the juice, the recovering of various compounds such as organic acids contained in molasses could contribute to increase the competivity of the sugar industry. Therefore, according to the biorefinery approach, we propose to study the chemical conversion of one of these acids, the aconitic acid, by esterification reactions. A new series of aconitate esters have been synthesized by combining aconitic acid and alcohols from natural origin. The effects of experimental conditions have been investigated and have shown that the type of catalysis has a significant effect on the selectivity. Kinectics have thus been performed to determine the best conditions to synthetize enriched compositions in esters. Homogeneous catalysis generates the highest yield in triester. Heterogeneous catalysis (macroporous resins) is prefered for the production of monoesters while catalysis assisted by ionic liquid is adapted to prepare mainly diesters. Green indicators have been discussed according to the calculations performed. The resulting polyfunctional esters are totally biosourced molecules and have a great potential as bioproducts for different applications.  相似文献   

14.
In order to investigate effects of injection molding conditions on viscoelastic behavior and thermal deformation of film insert molded (FIM) parts, injection molding was performed with various conditions such as injection speed, melt temperature, and packing time. It was shown that variation of the warpage was decreased monotonically with increasing injection speed and exhibited a bell-shaped curve as a function of melt temperature. Warpage variation was not affected by the packing time significantly and the proportional relationship between warpage of the film insert molded part and shrinkage of the injection molded part without film was observed. The FIM specimens produced with unannealed films showed the warpage reversal phenomenon (WRP) during annealing and the magnitude of reversed warpage was affected significantly by the injection parameters and the extent of thermal shrinkage of the unannealed film. Warpage of the FIM specimen was predicted by three dimensional numerical flow and stress analyses and the predicted values showed a good agreement with the experimental results.  相似文献   

15.
Antitranspirants (AT) were applied to greenhouse, field research plots and commercial plantings of Norgold Russet potato plants. In the greenhouse AT (Folicote and Vapor Gard) reduced water uptake by plants by 20–40%. In field trials at the Texas Agricultural Experiment Station, Halfway, similar concentrations increased yield of Norgold Russet potatoes by 21–45 cwts per acre (2352–5040 kg/ha). In a commercial trial on 20 acres of potatoes, 2% Folicote applied 5 and 3 weeks prior to vine kill increased total yield by 47 cwts per acre (5264 kg/ha) and increased yield of premium grade potatoes by 100%. Gross crop value at harvest was increased $500 per acre ($1125/ha). Significantly higher soil moisture levels existed in soils of treated plots between irrigations.  相似文献   

16.
The productivity of Vicia sativa grown in rotation with barley under rainfed Mediterranean conditions was examined at two locations over several years (eighteen location × year situations). Rainfall during the growing season ranged from 200 to 500 mm. Vetch relied on indigenous rhizobia for nodulation and N fixation while for phosphorus it was fertilized with 20kgPha−1. Harvesting took place at the beginning of pod formation. The dry matter (DM) yield reached 6·6t ha−1 and the N offtake 215 kg ha−1. The highest yields were obtained when rainfall exceeded the 350 mm level. The N concentration of the forage was not influenced by rainfall or by the productivity of the plants. Yield of DM was related to the number of days of ground frost in January but not in February and March. Monthly minimum and maximum temperature was not related to the DM yield. The combination of monthly rainfall and temperature explained over 95% of the variation in yield.  相似文献   

17.
In this paper, detailed simulation of human hair bleaching was conducted. The materials and chemical used as well as the hair bleaching procedures were described. After bleaching, the colour change of the hair was evaluated in accordance with CIE Lab system and the hair bleaching results was analysed. Following the hair bleaching process, hair coloration was employed with the use of colour boosting shampoo with henna of three different colours. The effect of different bleached hair samples on colour uptake property was examined by spectrophotometer method. Based on this study, it was concluded that the original hair colour did affect the colour uptake using the colour boosting shampoo with henna significantly. In order to have a visible coloring result, hair bleaching treatment was therefore highly recommended before conducting the hair coloration process.  相似文献   

18.
气象条件对棉花蕾铃脱落影响的探讨   总被引:2,自引:0,他引:2  
棉花是彭泽县的传统大产业.棉花的增产潜力是在充分满足其生长发育的肥、水、光、温和管理等多方面条件下形成的.而其中气象条件造成棉花的蕾铃脱落,对棉花的稳产和高产的影响关系极大.为此,我们进行了初步的探讨.  相似文献   

19.
In 1976, 1977 and 1978 a red clover-perennial ryegrass sward was cut twice for silage, and in the autumn of 1976 and 1977 it was either grazed at low and high stocking rates, i.e. seventeen and thirty-four lambs per ha respectively, or was cut with a forage harvester. The effects of grazing on yield in the following year were examined. Herbage growth in the grazing period was slow and did not differ significantly between the treatments. The yield of silage dry matter taken in May and July was highest in ungrazed plots (9·8 and 8·1 t ha-1 in 1977 and 1978 respectively) and lowest in plots stocked at the high rate (5·9 and 5·7 t ha-1 in 1977 and 1978 respectively). The aftermath yield for grazing in 1977 was slightly but significantly greater on treatments grazed in the previous year compared with ungrazed treatments. Red clover content decreased markedly during grazing, the high stocking rate treatment containing 2·4% clover and the ungrazed treatment 57·3% clover. The high stocking rate treatment also had the lowest red clover content in the first silage cut. Red clover content in grazed plots increased to a level similar to that in ungrazed plots by the start of the grazing period in the subsequent harvest year. Animal performance was higher at the low than at the high stocking rate but herbage consumption per head did not differ significantly between the two grazing treatments. Possible reasons for the adverse effect of grazing on the red clover are defoliation and treading. It is concluded that such experiments can form the basis of an economic assessment of red clover and help the farmer decide whether or not he should integrate the crop into his system.  相似文献   

20.
In this paper, viscose rayon-based knitted fabrics were utilized as the precursor to produce activated carbon fiber absorbents (ACFA). The effects of carbonization and activation conditions on characteristics (ACFA) were examined. Experimental results revealed that increasing the flow rate of environmental gas N2 and steam activator used in conjunction and decreasing the production rate of ACFA can obtain better pore properties. However, higher flow rate of steam activator and lower production rate of ACFA reduced the weight yield. According to our findings, to maintain good absorption property of ACFA, the optimum manufacturing conditions are flow rate of gas N2 at 80 cc/min, flow rate of steam activator at 60 ml/min, and production rate of ACFA at 30 cm/min, with flame retardant reagent concentration maintained at 30%. Under these conditions, the weight yield can be up to 40.85% and the BET surface area can exceed 1500 g/m2.  相似文献   

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