新型肉羊—兴绿原羊特性

兴绿原羊是北京市兴绿原农牧发展有限责任公司以国家“八五”科技攻关成果“集约化繁殖肉羊”为依托而繁育出的一种优质肉羊。其主要特性是:1.个体大,成年公羊每只可达150kg以上,优质肉块的比例高,生长迅速,6个月可出售,当年即可受益。2.繁殖率高,常年发情,一年两胎。

绵羊的系统分类和种系发生

绵羊 (Ovis)属的许多物种和亚种与家养绵羊有遗传上的关系 ,对绵羊遗传育种研究和商品肉羊生产有重要参考价值。中国地方品种绵羊的祖先大多与各类盘羊有关系 ,与欧洲和亚洲的摩弗伦羊和原羊有明显的遗传距离 。

Antibody Detection on Mycoplasma capricolum subsp. Capripneumoniae in Qinghai Province

[Objective] The aim was to investigate the prevalence of Mycoplasma capricolum subsp. Capripneumoniae in Qinghai Province. [Method] By using indirect hemagglutination test kit for detecting Mycoplasma capricolum subsp. Capripneumoniae,208 goat serums were detected. [Result] The positive rate of goat sera was 16.3%,and the positive rate of sera from different regions ranged from 6.7% to 24.3%. [Conclusion] The infection rate of Mycoplasma capricolum subsp. Capripneumoniae was high in Qinghai Province,so it is necessary to strengthen the prevention and control of this disease.

Culture of Embryonic Stem Cell by Primordial Germ Cells of Down Producing Goat

[Objective] The paper was to establish embryonic stem cell system of goats. [Method] Numerous primordial germ cell colonies were derived from gonadal ridge and the surrounding tissues in 20 millimeter fetuses of down producing goat. Primordial germ cells and goats embryonic fibroblasts obtained from conceptus of equivaient gestational age were co-cultured. [Result] The colonies showed some characteristics of embryonic stem cells, such as the morphology of nest-like, they continued to be AKP positive and the ability to be continuously passed [Conclusion] These cells were pluripotent and ES-like cells.

Soil Carbon Balance in a Native Temperate Grassland in the Xilin River Basin of Inner Mongolia

Based on historical data and field investigation, some major fluxes and reserves of carbon were estimated, and a tentative analysis of the soil carbon balance was made in a native grassland community in the Xilin River basin of Inner Mongolia. Major results were reported as follows: 1) Annual average carbon input from above-ground biomass production was 79.8 g C(.)m(-2.)a(-1), and from root biomass to 30 cm. depth averaged 311.9 g C(.)m(-2.)a(-1). The summed mean annual carbon input of shoot and root materials in the study site was approximately 391.7 g C(.)m(-2.)a(-1). 2) The annual amount of above-ground biomass consumed by insects averaged 14.7 g C(.)m(-2.)a(-1), and the carbon output by leaching or light-chemical oxidation was 3.2 g C(.)m(-2.)a(-1) The annual evolution rate of CO2 from net soil respiration averaged 346.9 g C(.)m(-2.)a(-1), and the summed mean annual output was approximately 364.8 g C(.)m(-2.)a(-1). 3) A mature, steady-state system could be assumed for the community for which growth and decay were approximately in balance, with a net carbon accumulation of about 26.9 g C(.)m(-2.)a(-1). Based on the soil organic carbon density of the field, the turnover Irate of soil carbon in 0 - 30 cm depth was calculated to be 6.2%, with a turnover time of 16 years.

羊痘病的诊断与防治

喜德县属低纬度高海拔中亚热带季风气候,具有雨量集中、热量丰富、气温年较差小、日较差大等特点,冬暖干燥,夏凉湿润,无明显四季之别。由此,羊痘病在我县春冬季时高山地区时有发生。本文就对去年本县地处海拔2400m的某乡某村58户农户673只羊发生羊豆病时笔者的诊断、治疗进行分析。

用粉笔作演示教具八例

粉笔是教师上课必带的用品,用于板书和板图。在生物教学中,粉笔又可作演示教具。现举八例如下: 1.在讲分裂生殖对,用一支粉笔当成一个单细胞生物。把这支粉笔平分为二份,就可表示一个单细胞生物母体分裂成大小和形状大体相同的两个子体。这种生殖方法叫做分裂生殖。

Diurnal and Seasonal Dynamics of Soil Respiration at Temperate Leymus Chinensis Meadow Steppes in Western Songnen Plain, China

To evaluate the diurnal and seasonal variations in soil respiration （Rs） and understand the controlling factors, we measured carbon dioxide （CO2） fluxes and their environmental variables using a LI-6400 soil CO2 flux system at a temperate Leymus chinensis meadow steppe in the western Songnen Plain of China in the growing season （May-October） in 2011 and 2012. The diurnal patterns of soil respiration could be expressed as single peak curves, reaching to the maximum at 11：00-15：00 and falling to the minimum at 21：00-23：00 （or before dawn）. The time-window between 7：00 and 9：00 could be used as the optimal measuring time to represent the daily mean soil CO2 efflux. In the growing season, the daily value of soil CO2 efflux was moderate in late spring （1.06-2.51μnol/（m2.s） in May）, increased sharply and presented a peak in summer （2.95-3.94 μmol/（m2.s） in July）, and then decreased in autumn （0.74-0.97 μmol/（m2.s） in October）. Soil temperature （Ts） exerted dominant control on the diurnal and seasonal variations of soil respiration. The temperature sensitivity of soil respiration （Q10） exhibited a large seasonal variation, ranging from 1.35 to 3.32, and decreased with an increasing soil temperature. Rs gradually increased with increasing soil water content （Ws） and tended to decrease when Ws exceeded the optimum water content （27%） of Rs. The Ts and Ws had a confounding effect on Rs, and the two-variable equations could account for 72% of the variation in soil respiration （p 〈 0.01）.

Effect of Nitrogen Fertilizer on Photosynthetic Rate of Leymus chinensis in Grassland of Different Degrading Degrees

[Objective] This study aimed to investigate the effect of nitrogen fertilizer on photosynthetic rate of Leymus chinensis in the grasslands of different degrading degrees. [Method] With the L. chinensis in Inner Mongolia Baiyinxile Ranch as the research object, different rations of nitrogen fertilizer were applied to the grassland （0, 30, 50, 80 g/m^2）. The effect of different gradients of nitrogen fertilizer on photo- synthetic rate of Leymus chinensis, and the effect on grasslands of different degrading degrees were analyzed. [Result] The photosynthetic rate of L. chinensis in- creased with the increase of nitrogen gradients; in the grassland communities with different degrading degrees, the responses of the photosynthetic rate of L. chinensis to nitrogen fertilizer were different, and the response in the grassland with severe degradation was the best. [Conclusion] Nitrogen fertilizer played an important role in enhancing the restoration degree of grassland.

Responses of Phytolith in Guinea Grass(Leymus chinensis) Leaves to Simulated Warming,Nitrogen Deposition and Elevated CO_2 Concentration in Songnen Grassland,Northeast China

Deposited in plant cells and their intercellular space,phytoliths,a special form of silica,could be used to determine information on plant structure and physiology especially their size and content.With the hypothesis that phytolith in plant would change under variable climate and environment,the dominant plant species in Songnen grassland,guinea grass(Leymus chinensis),was treated by an open-top chamber(OTC) to elevate CO2 concentration,infrared heaters,and artificial nitrogen(N) addition for three years from 2006–2008.Phytoliths were extracted by wet-ashing method and analyzed by variance analysis and so on.We found that the responses to elevated CO2 are complicated,and warming is positive while N addition is negative to the deposition of phytoliths in L.chinensis leaves.Especially,warming could reduce the negative impact of N addition on phytolith in L.chinensis.The short cell's taxonomic in graminea is significant because of no disappearance with simulated environmental changes.The phytolith originated in the long cell and plant intercellular space are more sensitive to elevated CO2 concentration,warming,and N addition,and could become some new indicators for environmental changes.In conclusion,different phytolith types have various responses to simulated warming,N addition and elevated CO2 concentration.

Effect of Leucaena leucocephala （Lam.） and Sodium Lauryl Sulfate in Meat Goat Diets on Nematode Eggs and Protozoa Interaction in the Rumen

The effeclt of condensed tannins from Leucaena leucocephala （Lam.） and sodium lauryl sulfate （SLS） addition to basal diets of corn silage on nematode eggs and protozoa interaction in the rumen within Thai native x Anglo-Nubian male goats was studied. Goats （n = 24 male; BW = 30 ＋ 2） were randomly considered toward treatment position into randomized complete block design （RCBD）. The treatments were： 1） Basal （B; 1.0-1.2 kg/head/day, corn silage）, 2） B ＋ SLS 8 g/head/day） 3） B ＋ 40g Leucaena/head/day （1.0% condensed tannins）, and 4） B ＋ 40g Leucaena/head/day （1.0% condensed tannins） with SLS 4 g/head/day）. These studies indicate that the action of 1.0% condensed tannins by Leucaena with 8 g SLS has the effect of increasing C3 （P 〈 0.05）. The opposite effect was observed for C2 which decreased （P 〈 0.05）. Both intestinal nematode eggs and protozoa in the rumen were reduced highly significantly （P 〈 0.01）. Bacteria population was raised （P 〈 0.01）. Nevertheless, all of these treatments did not affect intake, productive performances and blood urea nitrogen.

Influence of litter layer on ecological environment in northeastern leymus chinensis grassland of China

In this paper, we adopted simulation method to discuss influences of litter layer on plants habitat in grassland. Results indicated that ground surface evaporation, soil moisture, surface temperature, soil pH, soil bulk density and soil porosity were all strongly related to the litter quantity. Potassium （K） and organic materials in the soil covered by litter layer were higher than those in the soil uncovered by litter layer. With 100 g.ln-z increase of litter, the percentage of organic materials increased by 17.9%, nitrogen （N） increased by 7.6%, phosphor （P） increased by 26.4%, and K increased by 3.8%. With the litter accumulation amounting up to 600 g-m-2, the percentage of organic materials increased by 1.8 times, N increased by 81.5%, P increased by 1.8 times and K increased by 26.4%. According to the expected coefficient method of optimization, a mathematical model was established about the optimal accumulation quantity of litter.

Economic Feasibility of Simultaneous Production of Pine Sawlogs and Meat Goats on Small-Sized Farms in Alabama

The objective of this study were to conduct economic evaluations of silvopasture farming system to enable landowners, extension personnel, and other decision makers to correctly assess its potential among the many land-use options; and to determine the most profitable animal stocking rate on small farms in Alabama. The analysis draws on data from a silvopastoral experiment conducted in the Alabama Black Belt region, on the property of the Federation of Southern Cooperatives in Epes, Alabama, between June 2006 and July 2010. Economic and financial ratio analyses were used to compare profitability, management feasibility, and risk considerations of simultaneous production of pine sawlogs and meat goats on small-sized farms in Alabama. The results suggest that silvopasture technology is profitable and financially feasible under specified assumptions. The Net Present Value model suggested that investing in silvopasture system would be considered acceptable at the 6 percent discount rate at a high stocking rate of 8 meat goats per acre. These findings were reaffirmed by the financial feasibility analysis.

A COMPARATIVE STUDY OF GUT SUTURE, HUMAN AMNION COLLAGEN, BOVINE SKIN COLLAGEN AND VICRYL SUTURE IMPLANTS IN RATS

This study compares the persistence and histological characteristics of gut suture with those of human amnion collagen, bovine collagen, and Vicryl suture implants in rats. Gut suture and human amnion collagen more resembled living tissue than did bovine collagen and were characterized by their cel1ularity and the presence of numerous capillaries. The Vicryl suture implants were quickly absorbed. Picrosirius polarization revealed the synthesis of host collagen by rat fibroblasts which immigrated into the gut suture and human amnion collagen implants. The authors suggest the potential of gut suture as a soft tissue substitute to improve linear skin contour deficits.

Justicia insularis Improves the in vitro Survival and Development of Ovine Preantral Follicles Enclosed in Ovarian Tissue

Objectives： Evaluating the addition effect of./. insularis extract and FSH on the survival, activation and ROS production after in vitro culture of ovine preantral follicles enclosed in ovarian tissue. Methods： In the first experiment, ovarian fragments were fixed （non-cultured control） or in vitro cultured in α-MEM＋ （cultured control）, α-MEM＋ supplemented with FSH 50 ng/mL, or in α-MEM＋supplemented with J. insularis （JUS0.3; 1.25 or 5 mg/mL） for 1 or 7 days, at 39℃, 5% CO2. In the second experiment, fragments were fixed or cultured in α-MEM＋ supplemented with anethole 300 μg/mL ＋ FSH 50 ng/mL or in α-MEM＋ supplemented with anethole 300μg/mL ＋ 0.3 mg/mL JUS. Key findings： JUS0.3 was the only treatment that maintained the percentage of morphologically normal follicles similar to non-cultured control even after 7 days of culture. After 7 days of culture, a higher （p 〈 0.05） percentage of developing follicles was observed in JUS5 treatment compared with the other treatments except JUS 1.25. In the second experiment, FSH maintained the percentage of normal follicles and promoted activation of primordial follicles. A reduction （p 〈 0.05） of stromal cell density was observed in MEM＋＋ANE supplemented with JUS or FSH. Conclusions： J. insularis in a concentration-dependent manner maintained the levels of ROS and improved in vitro follicular survival and activation of ovine primordial follicles.

草原保卫战

天苍苍,野茫茫,风吹草低见牛羊……在草原的波涛起伏中,草原牛和草原羊正一边吃草一边聊天。草原牛对草原羊说:"美女,你最喜欢听谁唱歌?"

草原保卫战

天苍苍,野茫茫,风吹草低现牛羊……在草原的波涛起伏中,草原牛和草原羊正在一边吃草一边聊天。他们说话间,忽然听到天空中传来巨大的"嗡嗡"声,抬头一看,一片"乌云"

西风飘起发如焰

我在高原之上,聆听白雪飘落的声音,从来都以放松的心情感受时间的流逝和岁月的沧桑。我在西北独自漫步,希望得到一种启迪,但我并不知道该是什么。我困惑,但找不到原因。