我国牛冷冻精液质量性状的评估与分析

为进一步探索冷冻精液的质量提高与技术关键,本研究对近年来国内各牛冷冻精液生产企业1720头份精液样品进行了质量分析,涉及品种有奶牛、肉牛类（包括乳肉兼用、黄牛、牦牛等）和奶水牛等。结果：剂量值(0.20±0.008)mL、活力(40.9±2.3)%、每剂量前进运动精子数(1224.3±291.7)万个、畸形率(12.6±3.8)%、细菌菌落数(38.9±192.7)个。年度间比较,活力呈不规则的起伏变化;畸形率2016年均值显著低于前二个年度,分别下降0.8%和1.3%,3个年度间均差异显著(P＜0.05),细菌菌落数2014年显著高于其他二个年度(P＜0.05);品种间比较,奶牛活力分别高于奶水牛0.5%、肉、兼用牛0.2%(P＜0.05),奶水牛与肉牛及兼用牛之间差异不显著(P＞0.05),奶水牛畸形率分别高于奶牛1.9%、肉用牛0.9%,均差异显著(P＜0.05),前进运动精子数,奶水牛最高,奶牛最低,品种间均差异显著(P＜0.05);生产企业间比较,活力、前进运动精子数、畸形率均分别存在不同差异。通过数据分析,反映了目前国内牛冷冻精液的质量概况,为冷冻精液的技术研究提供依据。     

安徽省农业源温室气体排放特征研究

安徽作为农业大省,农业源温室气体排放量巨大,笔者旨在对其农业源温室气体排放特征进行研究。研究方法为省级温室气体清单编制方法《省级温室气体清单编制指南（试行）》。结果表明：安徽省2005、2010、2012、2014年的农业源温室气体排放量折合二氧化碳当量(CO₂ e)分别为3916.97万、3246.90万、3182.70万、3313.20万t,CH₄、N₂O各占一半左右;其中又以种植业为主,约占70%左右。种植业的排放量相对稳定,4个年度的上下变化约45.11万t,仅占2012年种植业排放量的1.85%,这是由于安徽省的种植业从种类、规模到产量处于基本稳定状态;养殖业排放量变化则非常大,2005年排放量显著高于其他3个年份,这是由于安徽省农业生产模式由畜力向机械化转变、耕牛存栏量大幅度减少造成。随着奶牛、肉牛存栏量的增加,养殖业的排放量呈增长趋势。综上,安徽省的农业源温室气体排放量可能发生较大的增加,有效措施应该采取起来以抑制畜牧业排放量的增长趋势。     

草原生态保护补奖政策下牧区半牧区的牧业生产及牧民收入分析

为进一步了解草原生态保护补奖政策实施以来对中国牧区半牧区的作用影响,本研究分析了草原生态保护补奖政策前后,中国牧区半牧区的牧业生产、牧民收入的变动情况。结果显示,草原生态保护补奖政策实施后,牧区半牧区的牛出栏量及牛肉产量基本稳定,羊存栏量、羊出栏量、羊肉产量、奶产量均有不同程度增加;农牧民人均纯收入、牧业收入、牧业收入比重呈持续增加态势。最后提出要进一步转变牧区牧业生产方式,逐步提高牧民收入水平,完善草原生态保护补奖的配套政策等建议。     

安徽省部分地区牛血清硼含量检测与分析

选择临泉县、庐江县、蚌埠市、黄山市为采样地点，采集不同年龄、不同品种、不同性别牛血清，用姜黄素法测定安徽省部分地区牛血清硼含量。结果显示：临泉县、庐江县、蚌埠市、黄山市牛血清硼含量依次降低，且临泉县与庐江县、蚌埠市、黄山市牛平均血清硼含量相比差异极显著（p<0.01），而庐江县、蚌埠市、黄山市牛平均血清硼含量相比差异不显著（p>0.05）；不同品种牛相比，黄牛、水牛、奶牛的血清硼含量依次降低，且黄牛血清硼含量与奶牛、水牛相比差异极显著（p<0.01），水牛与奶牛相比差异不显著（p>0.05）；雄性水牛血清硼含量比雌性水牛血清硼含量高，但差异不显著（p>0.05）。     

Change in the Concentration of Employment in Computer Services: Spatial Estimation at the U.S. Metro County Level

ABSTRACT This article models the concentration of computer services activity across the U.S. with factors that incorporate spatial relationships. Specifically, we enhance the standard home‐area study with an analysis that allows conditions in neighboring counties to affect the concentration of employment in the home county. We use county‐level data for metropolitan areas between 1990 and 1997. To measure change in employment concentration, we use the change in location quotients for SIC 737, which captures employment concentration changes caused by both the number of firms and the scale of their activity relative to the national average. After controlling for local demand for computer services, our results support the importance of the presence of a qualified labor supply, interindustry linkages, proximity to a major airport, and spatial processes in explaining changes in computer services employment concentration, finding little support for the influence of cost factors. Our enhanced model reveals interjurisdictional relationships among these metro counties that could not be captured with standard estimates by state, metropolitan statistical area (MSA), or county. Using counties within MSAs, therefore, provides more general results than case studies but still allows measurement of local interactions.     

不同肉牛生产规模的经济效益比较分析

在深入实践大量调查研究的基础上,结合张掖地区肉牛养殖规模,饲料资源情况和牛群资源现状,分别比较不同肉牛育肥生产养殖规模的经济效益。表明饲料成本的投入明显影响肉牛育肥的效益,以规模养殖的效益为较佳。     

Wnt7a和孕酮受体在人工受精奶牛受孕前后表达规律研究

旨在筛选奶牛早期妊娠诊断标志因子,将奶牛早期妊娠检测时间窗口提前提供理论基础,从而提高奶牛养殖经济效益。北京某牛场选10头荷斯坦奶牛,在输精后第1、4、7、10、13、16、19天取血,通过荧光定量PCR和western blotting方法分析Wnt7a和PR的表达趋势和变化规律。通过直检对10头荷斯坦奶牛的怀孕检测,其中有7头受孕3头未受孕。通过检测受孕和未孕的奶牛血液中Wnt7a基因和PR基因的表达量,发现Wnt7a基因在受孕奶牛血液中的表达量均高于未孕奶牛,特别是输精后第7天受孕奶牛的表达量显著增高,Wnt7a的蛋白质水平表达呈现出类似趋势;PR基因在全部10头奶牛中呈现出从输精后第一天表达开始降低,并一直维持一个很低的表达状态。Wnt7a具有作为奶牛早期妊娠诊断标志因子的潜质,其优势在于将检测窗口提前到输精后的第7天;PR不具有作为标志因子的优势。通过探究影响早期妊娠的相关因子变化规律,可以为孕检的时间窗口提前到早期妊娠阶段提供理论依据。     

以发展沼气工程为纽带的中国绿色农业发展思路

为了解决化石农业和规模化饲养业生产的残余物,包括农作物秸秆、畜禽排泄物和食品加工三废物质等的堆积污染问题,本研究提出一个以点面结合,网状发展现代化沼气工程为纽带的现代化绿色农业的产业化构想。它是以农作物秸秆和规模化养殖场的畜禽排泄物为原料,集沼气发电与配送、沼渣有机肥商品化生产支撑有机栽培、沼液规模化养殖经济微藻发展动物保健饲料为一体的绿色农业系统工程。经过技术集成配套、反复演练,该工程有望解决化石农业和规模化饲养业生产的残余物堆积污染问题,成为中国绿色农业、有机食品和能源农业可持续发展的基本方向。     

中国畜产品生产分析预测及饲草发展对策

对中国畜产品生产能力进行了分析预测,并提出了发展饲草的对策建议。结果表明,(1)近年来中国畜产品生产结构将发生明显改变,生产量将有较大幅度增长。(2)预计未来一定时期,猪肉生产增加缓慢,牛羊肉产量快速增加,2007年和2010年肉类总产量将分别达到8115万t和9150万t;奶牛存栏量和产奶能力将有一定增长,奶类总产量将分别为2462万t和2946万t。(3)中国饲草业将迎来一个快速发展时期,并逐步形成牧区以草地牧草为主、农区饲草和秸秆并重的畜牧原料生产格局。     

Does the recoupling of dairy and crop production via cooperation between farms generate environmental benefits? A case-study approach in Europe

The intensification of agriculture in Europe has contributed significantly to the decline of mixed crop-livestock farms in favour of specialised farms. Specialisation, when accompanied by intensive farming practices, leaves farms poorly equipped to sustainably manage by-products of production, capture beneficial ecological interactions, and adapt in a volatile economic climate. An often proposed solution to overcome these environmental and economic constraints is to recouple crop and livestock production via cooperation between specialised farms. If well-managed, synergies between crop and livestock production beyond farm level have the potential to improve feed and fertiliser autonomy, and pest regulation. However, strategies currently used by farmers to recouple dairy livestock and crop production are poorly documented; there is a need to better assess these strategies using empirical farm data. In this paper, we employed farm surveys to describe, analyse and assess the following strategies: (1) Local exchange of materials among dairy and arable farms; (2) Land renting between dairy and arable farms; (3) Animal exchanges between lowland and mountainous areas; and (4) Industrially mediated transfers of dehydrated fodder. For each strategy, cooperating farm groups were compared to non-cooperating farm groups using indicators of metabolic performance (input autonomy, nutrient cycling and use efficiency), and ecosystem services provision. The results indicate that recoupling of crop and dairy production through farm cooperation gives farmers access to otherwise inaccessible or underutilised local resources such as land, labour, livestock feed or organic nutrients. This in turn leads to additional outlets for by-products (e.g. animal manure). Farmers’ decisions about how to allocate the additional resources accessed via cooperation essentially determine if the farm diversifies, intensifies or expands operations. The key finding is that in three of the four crop-livestock integration strategies assessed, these newly accessed resources facilitated more intensive farming practices (e.g. higher stocking rate or number of milking cows per hectare) on cooperating dairy farms relative to non-cooperating, specialised dairy farms. As a consequence, cooperation was accompanied by limited environmental benefits but helped to improve resource use efficiency per unit of agricultural product produced. This article provides a critical step toward understanding real-world results of crop-livestock cooperation beyond the farm level relative to within-farm crop-livestock integration. As such, it brings practical knowledge of vital importance for policy making to promote sustainable farming.     

日粮中添加阳离子盐对泌乳期奶牛生产性能和离子平衡的影响

（目的）本研究旨在研究阳离子盐对奶牛生产性能和离子平衡的影响。（方法）试验选用泌乳期、产奶量和胎次都无显著差异的荷斯坦奶牛48头,随机分为4组,各组每头分别饲喂阳离子盐0 g/d（对照组）、20 g/ d（试验Ⅰ组）、30 g/ d（试验Ⅱ组）和40 g/ d（试验Ⅲ组）,试验期共55天。（结果）结果表明：试验组的产奶量普遍提高,但乳脂率、乳蛋白率、乳糖率变化不明显,同时提高了牛乳中K+、Na+、Ca2+、Mg2+,而阴离子Cl-和SO42-离子基本无变化（P>0.05）;血清中K+、Mg2+、Na+、Cl-含量变化不明显（P>0.05）,但显著增加了SO42-离子含量（P<0.05）。（结论）可见,泌乳期奶牛日粮中添加阳离子盐可以提高奶牛的产奶量,维持离子平衡,有利于保证奶牛健康。     

Pasture grazing intensity and presence or absence of cattle dung input and its relationships to soybean nutrition and yield in integrated crop–livestock systems under no-till

In integrated soybean–beef cattle systems, the pasture grazing intensity affects the grain crop performance in succession. In addition, the dung cattle input influences the soil nutrients distribution in the field affecting the grain crop yield. This experiment aims to evaluate the effects of winter pasture heights and cattle dung input in soybean crop performance in succession. Main soil macronutrient content, soybean plant population, dry shoot biomass, plant height, plant nutrient content, soybean yield and yield components were assessed in the 10th experimental year. The experiment was conducted in the state of Rio Grande do Sul, Southern Brazil, in a long-term integrated crop–livestock systems implemented in 2001. Treatments were arranged in a split plot design with four pasture heights (0.10, 0.20, 0.30, and 0.40 m) and two levels of dung input (with or without). For all the variables analyzed, there was no interaction between pasture heights and cattle dung input (P > 0.05). The pasture height management had only effect in soil P content, soybean dry biomass production, plant height and number of grains per pod. The increase in grazing intensity was associated to the rise in soybean plant height and dry mass production but was without effect on grain yield. The presence of grazing animals in the integrated soybean–beef cattle systems, and the resultant augmentation of dung input increased by 122% and 38% the availability of soil K and P, respectively in relation to the absence. Thus, the content of such nutrients in the plant were increased in 41% and 7%, respectively. The improvement in soybean nutrition increases the amount of pods per plant by 20%, and resulting in a 23% increase in soybean yield. These results indicate that cattle dung input resulting from grazing animals in the pasture phase increased soybean grain yield due to better plant nutrition. Although, the occurrence of cattle dung was very concentrated in some spots of the field and thus future studies should address strategies to improve spatial distribution of cattle dung input.     

特用玉米种子的可持续生产

玉米是主要粮食作物之一.在世界范围内,玉米的产量仅次于水稻、小麦而居第三位.玉米生产在过去的几十年里发展很快,对人们的生活和畜牧业的发展起着举足轻重的作用.在我国,玉米常年播种面积稳定在230万hm2左右,除了作为人们食用外,其大部分产品作为动物饲料.玉米栽培的类型绝大部分为马齿型和部分硬粒型品种,只有极少数为特用玉米.为提高玉米的价值,各国进行了种种努力,特用玉米生产就是其中一种途径.玉米潜在的特殊用途可基于现有的产品和开发新的产品相结合,以满足不断增长人口的需要.可以相信,随着经济的发展和人们生活水平的不断提高,特用玉米的种植面积将会不断扩大,特用玉米种子的需求量也会相应地提高.由于特用玉米的特殊性,它在生产过程中需要精心的管理和监测,所以特用玉米种子的可持续生产就显得尤为重要和迫切.     

微生态饲料添加剂研制和对肉牛血清中生理生化指标的影响

【目的】为研究和推广绿色肉牛规模化饲养技术,研制了绿色促生长微生态饲料添加剂,研究了其对肉牛血清中生理生化指标的影响。【方法】分离和筛选三株有益菌研制微生态制剂,选用条件一致的架子牛,对其血清中生理生化指标的影响进行研究。【结果】实验结果表明,分离的菌株和研制的微生态制剂符合安全标准,肉牛血清中甲状腺功能亢进或低下的三个关键指标（FT3、FT4、TSH）,在肉牛实验前后的变化属正常范围,肉牛血清中生长激素和胰岛素样生长因子含量高于对照组,但差异不显著（P﹥0.05）。【结论】结果提示,微生态饲料添加剂对肉牛血清中生理生化指标无不利影响,是安全绿色的饲料添加剂。     

Examining talent attraction and retention in small and medium-sized cities: Where do universities fit in?

As universities have become more integrated into their communities and regions, their host cities have become locations of choice for the highly educated facilitating increased innovation and productivity rates in several locales. Recent transitions toward knowledge-driven economies have also intensified growing geographic divides along the lines of education and raised concerns about the possibility of brain drain in a growing number of cities/regions. This study examines the changing geography of highly educated individuals (2000–2017) with a focus on small and medium-sized U.S. metropolitan areas with and without research universities. Results indicate the continuing trend of divergence among regions, but research universities are found to complement (the lack of) talent agglomeration and generate spatial spillovers beyond the county boundaries.     

Small‐scale cattle raising in East Java,Indonesia: A pathway out of poverty?

Despite its small area and intensively cropped landscape, East Java accounts for 30% of Indonesia's cattle population. About two million households draw on family labour to raise cattle in backyard sheds and small enclosures, largely for cash income. In this paper, we examine the opportunity for such small‐scale producers to benefit from Indonesia's economic transformation, given the rising urban demand for beef. The paper reports on a study in two contrasting sites in East Java – irrigated lowlands and rainfed uplands – to explore the constraints facing small‐scale cattle producers in these environments, the means by which they have adapted to these constraints (especially by going beyond the farm household to access feed supplies) and possible means to enhance their production systems and incomes. The findings suggest that such cattle production systems can provide a viable source of livelihood, even for resource‐poor households; hence, appropriately adapted cattle improvement programmes are a sensible component of a pro‐poor development strategy.     

美国奶业新特点、新趋势及对中国的启示

美国奶业发展历史悠久,其生产端、消费端乃至流通贸易方面长期积累的丰富经验,对中国奶业振兴具有一定的参考价值。笔者对2000年以来美国奶业生产、价格、消费、贸易等方面所呈现的新特点进行分析,对奶业相关的支持政策及其变化趋势进行梳理。研究发现,近年来,美国奶牛场数量向北部和西部集中,500头以上规模化牧场成为主流,奶牛存栏增加;技术进步推动奶牛单产突破10 t,生鲜乳产量接近1亿t。基于分级定价的乳成分定价机制不断完善,近5年生鲜乳价格低位运行,2019年快速复苏。乳制品加工业向龙头企业集中,奶酪是主要加工产品。乳制品消费逐年增长,年人均消费量达292.90 kg,奶酪是主要增长点且增速加快。乳制品贸易波动增加,出口目的地集中在北美、东亚和东南亚地区,品类以奶粉、奶酪和乳清为主。奶业产业支持政策广泛涵盖生产、消费、贸易等各环节,各政策间功能互补、协调配套,形成了强大的政策合力与综合效能。美国奶业在产业组织、运行机制、政策配套等方面的经验与做法,对推动完善中国奶业利益联结机制、优化生鲜乳价格形成机制、完善奶业支持政策体系和培育乳制品消费习惯等方面具有重要启示。     

Genetic variation in the feeding efficiency of maize genotypes evaluated from experiments with dairy cows

Genetic variation in the feeding efficiency of maize genotypes was evaluated from experiments with dairy cows. Maize genotypes were chosen to represent a range of digestibilities from previous experiments with standard sheep. The variation in milk yield observed with dairy cows fed genotypes with low or high digestibilities or energy values was about 1.0–2.0 kg per animal per day. Moreover, the range of variation in body weight was about 10–30 kg during the 3 months of the experiments. Hybrids with similar energy values had a similar effect on milk yield, but the intake of each hybrid could be very different when they were fed to dairy cows, even if no difference in intake had been observed in sheep. The higher silage maize intake of ‘DK265’ was mostly converted into a body weight gain rather than an increased milk yield, probably because the milk yield potential of the animals was soon reached. It appeared that those hybrids whose predicted energy value from sheep measurements was low led to relatively low performances in cows. Dairy cow performances also appeared to be related to the enzymatic solubility values of the whole plants. For maize breeders, the prediction of hybrid efficiency in dairy cow rearing must include digestibility and ingestibility factors. The most important challenge for maize breeders now will probably be the adjustment of a criterion for predicting intake because the stover digestibility and the starch content can be predicted reliably with the use of NIRS calibrations.     

一种简易的猪肉和牛肉分子生物学鉴别方法研究

建立了基于微卫星标记鉴别牛、猪肉制品的方法。根据微卫星标记种间特异性特点,从Genebank中筛选出牛微卫星SignⅠ和猪微卫星标记SignⅡ,并依据各个微卫星标记的侧翼序列设计引物。提取牛、猪肉各48个样品中的DNA作为模板,进行PCR扩增,电泳后得到了各自的目的条带379bp和585bp,根据目的条带的出现与否鉴别牛肉和猪肉。该方法进行鉴定灵敏度高,特异性好,而且方法简单,易于操作,结果易于判断。     

不同茬次的苜蓿干草在奶牛瘤胃中的降解规律的研究

摘要：选择装有永久性瘤胃瘘管,体重500 kg 左右并且均处于泌乳后期的3头健康中国荷斯坦奶牛,用尼龙袋法研究了不同茬次苜蓿干草的干物质(DM),粗蛋白(CP)和中性洗涤纤维（NDF),酸性洗涤纤维（ADF),在奶牛瘤胃内的降解变化规律。结果表明:在相同培养时间段内,不同茬次的苜蓿干草CP降解率依次降低(第一茬>第二茬>第三茬>第四茬),差异显著(P<0.05);NDF,ADF,粗脂肪降解率依次升高（第一茬<第二茬<第三茬<第四茬).差异显著（P<0.05)。