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101.
粗放管理条件下山西中部地区适用草坪草种评价   总被引:4,自引:0,他引:4  
选择北方地区建植草坪常用的草地早熟禾Poa pratensis、多年生黑麦草Lolium perenne、高羊茅Festuca arundinacea、匍匐剪股颖Agrostis stolonifera和白三叶Trifolium repens 为供试种,采用NTEP草坪质量评价体系进行了3年的引种评比试验.结果表明:在粗放管理条件下,高羊茅和白三叶适应性很强,其草坪质量保持性好;草地早熟禾次之,虽然其草坪质量下降较快、抗性较低,但草坪质量相对较好,可以与高羊茅以适当比例混播;多年生黑麦草和匍匐剪股颖适应性差,草坪质量下降速度很快,不适宜于低养护强度下在山西中部地区单播建植草坪使用.  相似文献   
102.
Rodents are globally important pre‐harvest pests of rice. In Southeast Asia, rodent damage to growing rice crops is commonly concentrated towards the center of rice fields, away from the field edge, resulting in a clear pattern known as the “stadium effect.” To further understand this behavior of rodent pests and to develop recommendations for future research and management, we examined the relation between giving‐up densities (GUDs) and damage patterns. In Tanay, Luzon, Philippines, GUD trays containing pieces of coconut in a matrix of sand were placed at 4 different distances from the field edge to quantify the perceived risk of predation in a rice field pest, Rattus tanezumi. GUDs were recorded during a dry and wet season crop at the reproductive and ripening stages of rice. In addition, assessments of active burrows, tracking tile activity and rodent damage to the rice crop, were conducted in the dry season. GUDs were significantly lower in the center of the rice fields than on the field edges, suggesting that rodent damage to rice is greater in the middle of rice fields due to a lower perceived predation risk. Furthermore, this perception of predation risk (or fear) increases towards the field edge and was greatest on the rice bund, where there was no vegetation cover. We discuss the implications for rodent management and rodent damage assessments in rice fields. This is the first documented use of GUDs in a rice agro‐ecosystem in Asia; thus we identify the challenges and lessons learned through this process.  相似文献   
103.
Abstract

The study aimed to identify important factors threatening genetic diversity within small sheep populations, and to propose sustainable management strategies. Demographic evolution, genetic diversity and current genetic management practices were analyzed in a population of Polish Olkuska sheep. Unbalanced contributions of individual rams to the next generation were observed due to differences in the period of their utilization, the number of progeny and the number of daughters used in reproduction. Matings between closely related animals were common. Pedigree completeness was satisfactory and inbreeding coefficient was high, 11.71% for lambs born in 2012. Relatively high values of potential and realized coancestries within flocks showed the importance of keeping more than one ram. The genetic conservation index and average relatedness coefficient, and their comparison between regions was helpful in considering management options. The information on genetic relationships and genetic conservation parameters of rams should be provided to breeders with simple interpretations.  相似文献   
104.
上市公司高层变动受多种因素的影响,经营业绩是其中一个重要因素,能有效反映公司经营绩效的财务信息,对高层变动的影响也是不容忽视的.通过对深市样本公司的高层变动与会计信息的实证分析,进一步证明了不同会计信息对高层变动的影响程度及二者的关系,从而为投资者和管理者及其他财务数据使用者提供有效的参考依据.  相似文献   
105.
从保证动物源性食品安全的角度论述了建立养殖场追溯体系的必要性,以出口兔肉备案养殖场为例,对建立追溯体系的步骤进行了四个方面的探讨。养殖场在设施合理、制度健全的前提下,确定追溯信息的深度、广度和精确度,并作好信息衔接和代码标识,才可使追溯体系有效实施。同时对追溯体系的应用和发展趋势做了基本论述。  相似文献   
106.
The implementation of the statutory Mineral Accounting System (MINAS) in the Netherlands in the period 1998–2003 required large reductions in nutrient inputs of dairy farms. Patterns in farm management adjustments throughout 6 years and their effectiveness in terms of nitrogen use efficiency (NUE) and economic performance were evaluated for 45 commercial farms participating in a regional nutrient management project.

Six groups of farms were identified that differed in initial NUE and the change therein. Three groups of farms that were able to rapidly reduce fertilizer N input and establish a consistent farm management strategy were most successful in improving NUE. These farms had a higher gross margin per 100 kg milk than farms without a consistent strategy. The three effective strategies were primarily characterized by (i) continuous, gradual adjustment of the integrated farm management combined with a slight reduction in milk production per ha (re-balancing) versus increasing productivity per animal, thereby reducing maintenance N requirements, while (ii) maintaining or (iii) increasing the production intensity per ha. It was concluded that different approaches to improve NUE can be successful, also in economic terms, although a direct relationship between NUE and gross margin was not observed. The probably implicit choice for adoption of a strategy may be governed by farm endowment and the farmer's skills and objectives.  相似文献   

107.

Background

Surgical castration is widely used to sterilize male dogs, but has significant impacts on time to perform the operation, recovery of the animals as well as cost, which can limit population control programs. Previous research has shown intratesticular injection of calcium chloride dihydrate (CaCl2) in saline to be a promising alternative to surgery. However, long-term azoospermia was not maintained at dosages low enough to avoid side effects. In the search for an optimized formulation, the current investigation is the first study on long-term sterilization effects of intratesticular injection of CaCl2 in either lidocaine solution or alcohol in dogs. CaCl2 at 20% concentration in lidocaine solution or alcohol was administered via intratesticular injection to groups of 21 dogs each. The treated animals were examined at 2, 6, and 12 months for sperm production, blood levels of testosterone, and side effects; at time zero and 12 months for testicular size and semen volume. The experimentally treated animals were compared to a control group receiving saline injection only.

Results

Testicles of dogs treated with CaCl2 in either diluent significantly decreased in size. After administration of CaCl2 in lidocaine solution, sterility was achieved for at least 12 months in 75% of treated dogs. However, optimal long-term contraceptive effectiveness was achieved with CaCl2 in alcohol, which resulted in azoospermia over the 12-month study period. Testosterone levels significantly decreased following treatment with CaCl2, and sexual activity disappeared. Although testosterone returned to baseline levels by 12 months for the group treated with CaCl2 in lidocaine, dogs injected with CaCl2 in alcohol had a 63.6% drop in testosterone level, which remained at the low end of physiological range throughout the study. No adverse effects were noted.

Conclusions

A single, bilateral intratesticular injection of 20% CaCl2 in 95% ethanol was a reliable method for induction of sterilization in 18–28 kg male dogs in this study. The approach showed long-term efficacy and reduced sexual behavior. This chemical method of sterilization might provide an effective, efficient alternative to surgical castration that can have positive impacts on dog welfare.  相似文献   
108.
Village breeding programmes are being developed by an integrated long-term project for smallholders in Northwest Vietnam to improve pig production in different production systems. In total, 120 smallholders with 169 sows in 5 of the 9 project villages were approached in single person interviews, using a structured questionnaire. Frequency analysis of data on breeding management and ranking of smallholders' trait preferences and selection criteria used for pigs were performed with SAS 9.1, using the FREQ procedure. Survey results indicate that both improved local breeds and exotic genotypes should be incorporated in future village breeding programmes for market-oriented smallholder pig production, improving the reproductive and growth performance as well as the carcass quality. In a next step, a model reflecting the status quo at farms with market-oriented pig production was developed integrating data from farmers' survey and information from the project's current recording scheme. A deterministic approach was used to assess the profitability and genetic merit of the current recording scheme. Modelling results show that the current recording scheme is unprofitable (− 33.90 € sow− 1). As continued success of village breeding programmes depends on the profitability of breeding measures, the long-term sustainability of the current recording scheme seems unlikely. Genetic gains are achieved in production and carcass quality traits, while a small reduction in reproduction traits can be observed. In a last step, possible effects of increased pig performances on the profitability and genetic merit of the current recording scheme were evaluated. Effects of increased pig performances on the genetic and economic success of the recording scheme are generally limited. Further model calculations are necessary for finding possibilities to improve smallholder pig breeding in a profitable way.  相似文献   
109.
松嫩草原区农牧林复合系统大型土壤动物生态学研究   总被引:11,自引:2,他引:11  
对松嫩草原区农牧林复合系统大型土壤动物群落的组成、空间分布、时间变化,以及与环境要素的相关关系进行了探讨。共获得大型土壤动物43类、1234只,优势类群是蚁科(Formicidae)和金龟子科(Scarabaeidae)幼虫,常见类群14类,稀有类群27类。水平分布表现出明显的不均一性,垂直分布类群数上均匀递减,个体数上表聚性明显。夏季类群数和个体数都明显多于秋季。地温对大型土壤动物影响最明显,其次是气温和降水。  相似文献   
110.
新西兰鹿业协会为加大鹿及鹿产品在国际市场上的竞争力,积极实施鹿福利制度。文中主要介绍了新西兰在鹿的运输、锯茸及饲养管理等方面所实施的具体福利措施。  相似文献   
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