宁波余姚市防护林带生态系统服务功能价值评估

以宁波余姚市防护林带为研究对象,建立了含有调节功能、文化功能和支持功能3大类共15项评估指标的生态系统服务功能价值评估指标体系,利用市场价值法、影子工程法和条件价值法等,定量评估了防护林带生态系统服务价值。结果表明:余姚市防护林带生态系统服务功能总价值为24 310.79万元·a~(-1),单位面积价值为24.31万元·hm~(-2)·a~(-1);净化大气环境、调节温湿度和涵养水源这3项功能是宁波防护林带的主导生态服务功能,分别占总价值的50.78%、24.45%和16.89%;与具有相似防护功能的上海市环城绿带相比,余姚市防护林带的生态系统服务功能单位面积价值稍低于上海市环城绿带。研究结果能为余姚市区域经济可持续发展和绿色GDP的核算提供科学依据。     

六盘山肉牛秋季舍饲育肥效果试验

选择不同日粮类型肉牛养殖户10户,参试生长公牛25头,参照肉牛营养需要和饲养标准,设计不同饲粮组合类型及日粮配方.随机分为6组,试验1、2、3组按设计标准配制日粮饲养,4、5、6组(CK)按传统方法饲喂,同期进行育肥试验.结果表明,试验1、2、3组头均日增体质量效果均比4、5、6组(CK)有明显提高.其中,试验1组期内平均日增体质量分别比试验4、5、6组(CK)提高94.22%、117.18%和145.07%(P＜0.01).     

道路边坡土壤水分空间和季节变异性分析

采用野外定位观测法,对柽柳、胡杨、骆驼刺和沙拐枣林地土壤水分状况进行监测,并通过实测数据对农田区和荒漠区0—100cm土层土壤水分特征曲线进行拟合。结果表明,各林地0—250cm土层土壤含水量均随深度增加逐渐增大,生长季内9月和10月份土壤表层含水量明显大于其它月份。一次强降雨对土壤表层含水量有所补给,对深层土壤影响较小。总体而言,土壤蓄水量(0—250cm)在月季间差异不大,均维持在120—140mm之间,但各林地有所差异,表现为:胡杨>柽柳>骆驼刺/沙拐枣。对整个生长季而言,4种植物蒸散强度呈现出:胡杨>沙拐枣>柽柳>骆驼刺,且6月份蒸散强度最大。农田区和荒漠区0—100cm土壤含水量与土壤基质势间幂函数拟合效果好。研究成果可为该区今后植被保育及生态用水提供理论参考。     

Effects of different fresh-cut forages and their hays on feed intake, digestibility, heat production, and ruminal methane emission by Boer x Spanish goats

Twenty-four yearling Boer × Spanish wethers were used to assess effects of different forages, either fresh (Exp. 1) or as hay (Exp. 2), on feed intake, digestibilities, heat production, and ruminal methane emission. Treatments were: 1) Sericea lespedeza (SER; Lespedeza cuneata), a legume high in condensed tannins (CT; 20% and 15% in fresh forage and hay, respectively), 2) SER supplemented with polyethylene glycol (SER-PEG; 25 g/d), 3) alfalfa (Medicago sativa), a legume low in CT (ALF), and 4) sorghum-sudangrass (Sorghum bicolor), a grass low in CT (GRASS). Experiments were 22 d, which included 16 d for acclimatization followed by a 6-d period for fecal and urine collection, and gas exchange measurement (last 2 d). Intake of OM was 867, 823, 694, and 691 g/d (SEM = 20.1) with fresh forage, and 806, 887, 681, and 607 g/d with hay for SER, SER-PEG, ALF, and GRASS, respectively (SEM = 46.6). Apparent total tract N digestion was greater for SER-PEG vs. SER (P < 0.001) with fresh forage (46.3%, 66.5%, 81.7%, and 73.2%; SEM = 1.71) and hay (49.7%, 71.4%, 65.4%, and 54.8% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.57). Intake of ME was similar among treatments with fresh forage (8.24, 8.06, 7.42, and 7.70 MJ/d; SEM = 0.434) and with hay was greater for SER-PEG than ALF (P < 0.03) and GRASS (P < 0.001) (8.63, 10.40, 8.15, and 6.74 MJ/d for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.655). The number of ciliate protozoa in ruminal fluid was least for SER with fresh forage (P < 0.01) (9.8, 20.1, 21.0, and 33.6 × 10(5)/ml; SEM = 2.76) and hay (P < 0.02) (6.3, 11.4, 13.6, and 12.5 × 10(5)/ml for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.43). Methane emission as a percentage of DE intake was lower (P < 0.01) for SER vs. ALF and GRASS with fresh forage (6.6, 8.3, 9.4, and 9.2%; SEM = 0.64) and hay (4.3, 4.9, 6.4, and 6.7% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.38). In summary, methane emission in this short-term experiment was similar between a legume and grass low in CT as fresh forage and hay. The CT in SER markedly decreased N digestibility and elicited a moderate decline in ruminal methane emission. Supplementation with PEG alleviated the effect of CT on N digestibility but not ruminal methane emission, presumably because of different modes of action. In conclusion, potential of using CT-containing forage as a means of decreasing ruminal methane emission requires further study, such as with longer feeding periods.     

Bovine thyroglobulin gene polymorphisms and their association with sexual precocity in Guzerat bulls

Puberty is a stage of sexual development determined by the interaction of environmental factors and genetic mechanisms. Among them, thyroid function plays a key role in sexual development and spermatogenic function and is under the control of several genes, including the well‐described thyroglobulin gene (TG). Previous reports have shown genetic association between thyroid function and selected single nucleotide polymorphisms (SNPs) in taurine cattle. Therefore, the identification of genetic mechanisms involved in the regulation of this trait can assist with the selection for early pubertal bulls, thus improving genetic progress in livestock breeding. The aim of this study was to validate the association between TG SNPs and age at puberty in zebuine bulls. Three SNPs (rs110406764, rs109662686, rs109057985) were genotyped in 159 Guzerat animals using SEQUENOM technology. Results showed a significant association (p < .05) between the studied SNPs and puberty age, in agreement with our previous reports in a taurine breed. Interestingly, allele frequencies were different from those already reported, being GAT the most favourable allele for age at puberty in Guzerat (94.4 days lower). Overall, our findings corroborate previous reports and reinforce the importance of genetic influence in the regulation of sexual development and puberty through a thyroid pathway in zebuine cattle.     

Advances in pasture management for animal productivity and health

A wide range of management techniques is available to enhance quantity and quality of forage supply to grazing animals throughout the annual production cycle. Within broad limits, dry matter (DM) production is relatively insensitive to management of defoliation frequency, severity and duration. However defoliation management has effects on feed quality which can be enhanced, in particular, by control of pasture growth in the spring through maintenance of relatively low average pasture masses. Treading damage can have significant immediate and ongoing effects on pasture production and farmers can use a range of management techniques to minimise these.

Fertiliser application practices have a potent influence on pasture production and seasonality of that production. Available soil nitrogen is the primary nutrient deficiency limiting production in New Zealand's characteristically grass-dominant pastures. Nitrogen fertiliser usage has increased markedly in recent years, particularly to grow substantially greater amounts of forage during the cool season, and this trend looks set to continue. However, the use of nitrogen fertiliser has important environmental implications.

Pasture renewal and forage crop use has also increased in recent years. Care needs to be taken in conducting cost-benefit analyses, selecting the options that best meet the needs, and in establishment and subsequent management practices. Ryegrass (perennial and hybrids) and white clover remain the primary choice for permanent pasture renewal, the availability of safe endophytes having largely alleviated effects of endophyte toxicosis. Special-purpose mixtures are used, especially in dry environments. Italian ryegrasses, brassicas and chicory are common choices for forage crops. A range of management techniques can be used to alleviate deleterious effects of some forages, including ryegrass endophyte toxicosis, facial eczema, and toxins associated with Fusarium fungi. Generally these techniques are not totally effective. More research is required to increase our understanding of these disorders, and in order to develop more effective and reliable management practices.     

奶业现代化趋势下小奶户发展研究——基于内蒙古呼和浩特地区小奶户的调研

我国奶业经过近20年的快速发展,取得了辉煌的成绩,但与奶业发达国家相比仍存在很多问题,尤其是奶牛养殖环节相对比较落后。此次奶源过剩及倒奶事件中,小奶户由于养殖规模小,成为事件主角,也是牛奶价格下降的最大受害者。目前部分小养殖户在养殖方式、机械化水平、牛奶质量安全水平方面都落后于规模化牧场,似乎与现代奶业格格不入,奶源的转型升级对其冲击最大。本文基于对内蒙古呼和浩特地区小奶户的调研,利用柯布-道格拉斯生产函数对小奶户家庭奶牛养殖数据进行了计量分析。模型结果显示,小奶户在其现有的资源条件下的生产具有效率,且生产的原奶交售价格远低于牧场的原奶价格。从解决农村就业及维持原料奶价格角度来看,小奶户在未来一段时期内仍将继续存在并发挥作用。对此,围绕奶业现代化趋势下小奶户发展所面临的困境,提出相应建议。     

把握时代脉搏办好省级农业科技期刊--《河南农业科学》办刊实践

《河南农业科学》编辑部为了适应市场经济的不断发展，以及应对入世所带来的冲击，在多年的办刊实践中，积极探索，开拓创新，通过采取多种行之有效的措施，使期刊的内外在质量不断提高，社会经济效益显著增强，走出了一条适合自身生存和发展的路子。