Converting to organic dairy farming: Consequences for production, somatic cell scores and calving interval of first parity Holstein cows

This paper aims to describe the changes prompted by conversion to organic farming for milk production and fertility of first parity Holstein cows.

Data was collected for Dutch organic farms, with a distinction made between long-standing-organic farms, converted organic farms and a reference group of conventional farms. The percentage Holstein blood in the herds, milk production (kg milk, % milk fat, % milk protein), somatic cell scores (SCS), calving interval (CI) and age at first calving (AFC) were described over time. An animal model was used to estimate the effects of conversion on different traits based on data from converted organic farms.

Milk production was lower and somatic cell counts were higher on long-standing-organic farms than on conventional and converted organic farms. Interestingly, at pre-organic farms, i.e. before their conversion, the milk production level was already lower than at conventional farms.

The estimates from our statistical analysis showed a highly significant decrease in milk yield and protein percentage due to conversion. Also fat content decreased, SCS increased and AFC increased significantly.

It can be concluded that the conversion to organic farming is a gradual process over years. Dutch farmers who decided during the late 1990s to convert to organic farming, represented a specific group of farmers distinct from conventional farmers, which was reflected by lower milk yields, milk fat percentage and protein percentage before conversion as compared to conventional farms. During conversion, significant changes in milk production, protein and fat contents and somatic cell scores took place. Age of first calving is an important difference between organic and conventional farming.     

天然复合矿物对肉猪生长性能,胴体品质影响的试验研究

９２头仔猪，分两批（每批４组）作基础日粮添加不同配方（Ａ、Ｂ、Ｃ）天然坚合矿物粉试验。结果表明，添加天然复合矿物粉对肉猪的生长性能及胴体品质均有一定的促进作用。其中以Ｂ方较稳定，日增重平均提高８．４％，料肉比下降９．２％，胴体瘦肉率提高５．０２百分点     

Extension Strategies in Sloping Land Conversion Program in China： An Analysis of Strengths and Limitations

INTRODUCTION Forests and Forestry are being paid more and more attention in the historical transformation from timber production to ecosystem management in China. The investment in forestry has been observably increasing, especially with an all-time scale of investment in forest ecological construction over recent years. There are 6 large forestry programs in China, of which 5 are direct ecological rehabilitation efforts. Besides other approaches such as technical assistance, financial s…     

基于农户调查的迁西县退耕还林可持续性研究

退耕还林工程实施后,其可持续性成为社会广泛关注的问题。以迁西县为例,对退耕还林的可持续性进行了研究。分别从粮食产量、土地利用及农业产业结构调整、农民经济收入、社会安全状况、退耕农民的思想观念变化等方面对迁西县退耕还林的可持续性进行了分析。得出迁西县在实施退耕还林工程后并未影响其粮食安全,土地利用及农业产业结构调整也较为合理,农民经济收入也保持了高速稳定的增长,农民思想观念亦有了很大转变,社会安全状况也可处于稳定状态,其毁林复耕的可能性极小。通过退耕还林工程的实施,迁西县基本达到了生态、经济和社会的可持续发展。     

基于农户调查的迁西县退耕还林可持续性研究

退耕还林工程实施后,其可持续性成为社会广泛关注的问题。以迁西县为例,对退耕还林的可持续性进行了研究。分别从粮食产量、土地利用及农业产业结构调整、农民经济收入、社会安全状况、退耕农民的思想观念变化等方面对迁西县退耕还林的可持续性进行了分析。得出迁西县在实施退耕还林工程后并未影响其粮食安全,土地利用及农业产业结构调整也较为合理,农民经济收入也保持了高速稳定的增长,农民思想观念亦有了很大转变,社会安全状况也可处于稳定状态,其毁林复耕的可能性极小。通过退耕还林工程的实施,迁西县基本达到了生态、经济和社会的可持续发展。     

论农民工向产业工人的转化

农民工是在我国经济社会转型时期,农村人口城镇化进程中出现的新型社会群体。经过多年市场经济的磨炼,农民工从整体上已具备中国产业工人的基本特征,是当代中国工人阶级的重要组成部分。在中国这样一个农民大国,要全面建设小康社会,推动社会主义新农村建设,应大力促进农民工向产业工人的深度转化,从本质与表征上将农民工融入中国工人阶级队伍。     

双氯芬酸钠残留检测的质谱条件选择

为优化双氯芬酸(DCF)残留检测过程中的质谱参数,提高其检测灵敏度。在电喷雾离子源负离子(ESI~-)和正离子(ESI~+)模式下,分别对DCF标准溶液进行母离子和子离子扫描,以优化定量检测的参数;比较ESI~-和ESI~+条件下,标准溶液和空白肝脏加标样品定量离子的响应。结果显示,在ESI~-模式下,DCF存在明显的源内裂解现象,而ESI~+模式下则未出现类似现象;因此导致质量浓度为2 ng/mL的DCF标准溶液在ESI~-条件下定量离子的峰面积远低于ESI~+;ESI~-条件下,空白肝脏加标样品(0.5 ng/g,LOQ)中几乎检测不到定量离子,而ESI~+条件下定量离子的响应则可满足检测要求。鉴于DCF在ESI~-条件下可发生源内裂解,建议在DCF的残留检测中采用ESI~+模式。     

利用葡萄糖合成烷基糖苷

[目的]以葡萄糖和十二醇为原料,在酸性催化剂对甲苯磺酸的作用下合成十二烷基糖苷。[方法]逐一考察了各个工艺因素对葡萄糖转化率的影响。[结果]确定了最佳工艺条件：剂糖比为0.010∶1,醇糖比为6∶1,反应温度为130℃,反应时间为3 h。在该条件下,葡萄糖的转化率达到72.5%。[结论]该法具有工艺简单、快速、高效等特点。     

城乡交错区农地城市流转管理控制目标的设定

城乡交错区农地城市流转的管理控制目标是:流转效益的最优化,即流转后经济价值、生态价值和社会价值能够达到或者接近最优化;通过流转使土地资源配置合理;土地流转收益分配合理。对流转前后土地经济效益、生态效益和社会效益的价值变化都提出了评估的思路和方法。