Modelling spring and autumn calving systems in beef herds of the Salado region of Argentina

Spring calving is recommended for beef herds in the Salado region of Argentina, but autumn calving is an alternative being used by some farmers. This study explored the biological and economic feasibility of autumn calving in cow–calf systems and their long-term performance compared with spring calving. Reproduction and calf performance data were collected from an autumn calving herd (1999–2005) and from a spring calving herd (1966–1995) at the INTA-Balcarce Research Station (37°45′ S; 58°18′ W). Similar data were obtained from a commercial farm which practiced both autumn and spring calving (1998–2003). These data showed that autumn calving is feasible in the region, provided that cows calve with a high condition score. This is a major difference with spring calving, where cows can normally gain weight during breeding. A climatically driven computer model was used to compare, at farm level, the effect of calving season across a range of combinations of weaning dates and stocking rates. Spring calving systems had greater production potential (15–20%) and profitability (17–28%) at high stocking rates. However, at low to moderate stocking rates, calving season had little effect on expected production and risk efficiency. This suggests that autumn calving could be a suitable alternative for the Salado region of Argentina. To exploit its potential, however, calf weaning age should be greater than with spring calving.     

种蛋孵化死胚及孵化厅环境样本中铜绿假单胞菌的分离鉴定及其耐药性分析

本研究旨在了解种鸡场中种蛋孵化死胚和周围环境中感染或污染铜绿假单胞菌(Pseudomonas aerugino-sa,PA)的比率及分离株的耐药性.从广东省的5个规模化种鸡场采集孵化厅死胚及其周围环境样本进行PA的分离鉴定,采用K-B纸片扩散法分析其抗菌药物敏感性,并通过常规PCR检测对应的耐药基因.结果 显示,在采集...     

An assessment of salmon farms and wild salmonids as sources of Lepeophtheirus salmonis (Krøyer) copepodids in the water column in Loch Torridon, Scotland

Wild salmonids and farmed salmon can both be sources of Lepeophtheirus salmonis (Krøyer, 1838) larvae . Farmed salmon smolts free of L. salmonis infections are stocked in sea cages and may subsequently contract L. salmonis infections, probably from wild fish. The contribution of gravid L. salmonis at Atlantic salmon, Salmo salar L., farms to populations of L. salmonis larvae in the water column has in the past been based on estimated parameters, such as louse fecundity. This present study augments these calculations by combining empirical data on densities of infective L. salmonis copepodids in the field with estimates of the number of gravid L. salmonis on farmed and wild salmonids in Loch Torridon. Data collected between 2002 and 2007 show a significant correlation between mean densities of L. salmonis copepodids recovered in the water column and the numbers of gravid L. salmonis at the local salmon farms. Generally, the farms with greatest numbers of salmon were observed to have stronger correlations with densities of copepodids in the water than the farms with fewer fish. The study suggests that louse management approaches, e.g. treatment trigger levels, need to take account of individual farm biomass, or numbers of fish. This study highlights the importance of control of L. salmonis on salmon farms for the co-existence of both wild salmonid populations and the aquaculture industry.     

秦安县畜禽养殖废弃物及农作物秸秆资源化利用现状及发展对策

随着畜牧业的快速发展,畜禽废弃物已成为制约畜牧业快速发展的关键性因素,是整治农村人居生活环境与乡村振兴所面临的一大难题。本文通过分析畜禽养殖场废弃物及农作物秸秆资源化利用现状,立足当地资源优势,提出对畜禽废弃物及农作物秸秆进行合理利用的发展对策,通过变废为宝,综合合理利用,农村的人居环境得到显著改善。     

通渭县生态放养鸡引进品种适应性试验

本试验基于甘肃省通渭县气候特点和生态资源优势,以该县永达碧林源养殖农民专业合作社为示范点,通过对引进芦花鸡、绿壳蛋鸡的适应性开展观测试验,继而筛选出成活率高、经济效益好、抗病能力强,适宜通渭县地区内放养环境的放养鸡品种,从而稳步推进通渭县养鸡业生产方式转变,发展节约型、健康型养鸡业,发展生态放养试验示范促进新技术在全县范围内推广。     

规模化蛋鸡养殖过程碳排放量核算与减排措施

畜禽养殖过程所产生的碳排放,在中国农业碳排放中占据很大比重,碳减排行动迫在眉睫。采用部分生命周期法评估规模化蛋鸡养殖企业在生产过程中产生的碳排放,结果表明温室气体主要来自于电力消耗、粪便处理和燃料燃烧环节。为减少养殖过程的碳排放,应当推行碳排放监测系统的建立、推动循环养殖的实践、注重发展清洁能源和节能技术,从根本上降低碳排放。     

黑龙江垦区农村居民点与田块间适宜耕作半径及影响因素

为探明黑龙江垦区农村居民点的适宜耕作半径及主要影响因素,该文以黑龙江农垦总局建三江管理局所辖八五九农场为研究区,以农场内的农村居民点为研究对象,利用2010年国土资源第二次调查矢量数据库,通过空间分析和多元线性回归的方法,进行了定量化的研究。研究结果表明:研究区内各个管理区的适宜耕作半径均值是5 055 m,耕作半径的最大、最小值分别为7 438和3 265 m;平均耕作半径对应农机出行时间为20 min,摩托车出行时间为10 min;适宜耕作半径与水田种植比例、土地面积、聚居居民点与对应连队几何中心偏差距离均值的显著性检验F值远大于F0.01,三者对适宜耕作半径具有极显著的影响,三者的回归系数依次为-17.892、0.208、-0.147,即水田种植比例较高的区域,适宜耕作半径相对较小;土地面积较大的区域,适宜耕作半径相对较大;偏差距离均值较大的区域,适宜耕作半径相对较小。     

家庭农场主群体特征调查研究

家庭农场主在家庭农场发展中的作用越来越突出。家庭农场主产生来源主要包括新型职业农民及返乡创业者。家庭农场主以男性居多,平均年龄较大,老龄化明显,学历水平较低,其个人特质如气质特征、性格特征、能力特征等也有差异。结合家庭农场主群体特征,建议加强农民职业培训,培育新型职业农民;加大农业人才引进力度,为家庭农场发展注入新的活力;提高农业信息化水平;完善农业保险制度,大力推动农业保险和商业化农业保险发展;扩大融资渠道。     

北京家庭农场发展模式探析

(目的)家庭农场作为一种新的农业组织形式近年在国内得到大力推广,但北京家庭农场的发展还处于试点阶段,还没有形成适合的模式。(方法)通过对北京在试点过程中出现的规模没有标准、劳动力缺乏、土地使用和劳动力成本高、市场运作能力弱、融资难等问题进行分析研究,借鉴上海、台湾、美国、德国、日本等国内外家庭农场发展的成功经验,(结论)提出因地制宜、适度规模,以特色农产品为抓手进行专业化生产,政策引导、制度保障、完善农业社会服务体系,发展生态型家庭农场,市场化运作、注重创新和加强农场主培训等发展方式,从而形成适宜北京的家庭农场发展模式。