青藏高原天然草场放牧家畜体重和体能量变化动态

用逐月称重法和季节屠宰试验获得青藏高原放牧家畜的体重和体能量沉积的季节动态。结果表明 ,放牧家畜在出生后第 1个冷季的体重下降幅度远低于第 2个冷季 ,高山细毛羊在暖季每千克增重的能量水平保持稳定 ,尽管秋季略有下降 ,但与夏季相比 ,差异不显著 ;牦牛在秋季每千克增重的能量则远高于夏季。牦牛和高山细毛羊在冬季每千克减重的能量水平远高于春季。牦牛和高山细毛羊在第 2个暖季所积累的能量约有一半以上在第 2个冷季被消耗     

近30年中国天然草地物候时空变化特征分析

基于遥感的大面积长时序草地物候监测是物候生态学的重要领域,也是全球变化研究的重要方向。基于30年(1986-2015年)时间序列GIMMS 3g归一化植被指数(NDVI),利用Savitzky-Golay滤波法进行时间序列重建,并用动态阈值法提取中国天然草地物候参数[生长季始期(SOS)、生长季末期(EOS)、生长季长度(LOS)],然后以1998年为时间分界点,利用提取的3种物候参数对前后两个时间段内的草地物候特征的时间演化趋势及空间分异进行分析。结果表明:1)全国草地年平均SOS、EOS和LOS分别主要集中在第100~140天、260~290天和130~170天;2)物候趋势在30年时间尺度上没有显著变化,幅度为-0.3~0.3 d·yr^-1;3)在1998年之前,全国草地SOS平均提前速率为0.37 d·yr^-1,EOS平均推迟速率0.43 d·yr^-1,且空间差异较大,在1998年之后草地物候变化趋势出现转变,草地SOS变化幅度最大,平均推迟速率为0.28 d·yr^-1;4)高山亚高山草甸、山地草原、平地草原和高山亚高山平地草原在1998年后物候特征变化趋势出现与之前完全相反的转折。提取物候结果与观测资料和相关研究结果较为一致。     

海南州草地牲畜超载与调控对策

对青海省海南州草地牲畜的超载状况进行了分析研究，提出了海南州草地牲畜的调控对策是：教育和组织群众，自觉按草畜平衡原则组织生产；挖掘生产内部潜力，调整畜群结构；增加科技与生产投入，提高草畜生产能力；建立草原监测制度，为确定合理载畜量提供科学依据。     

青海省草地植被干旱评估及驱动力分析研究

为了研究青海省草地植被干旱特征及驱动因子,以青海省草地植被覆盖区域为对研究对象,采用水量平衡和作物需水量等方法构建干旱评估模型,评估青海省草地植被干旱时空分布特征和发生趋势,并探讨形成干旱的关键驱动因素,结果表明：整个生长季东部农业区、环青海湖区、祁连山区大部草地植被基本维持轻旱和无旱,严重干旱区域集中在青南牧区的低覆盖度草地,干旱空间总体分布基本表现为低覆盖度>中覆盖度>高覆盖度;草地植被在整个生长季的干旱灾害类型以轻旱为主,中旱次之,重旱和特旱发生频率较低,极端干旱强度呈增加态势;降水和蒸散在整个干旱发生过程中驱动作用最大,且均为负向影响,随着干旱等级加重,蒸散逐渐代替降水成为影响干旱的最重要驱动因子。风速整体上对干旱的影响表现为正向,气温、日照时数和水汽压对干旱影响作用较小。     

Drought Evaluation and Driving Force Analysis of Grassland in Qinghai Province北大核心CSCD

This study was aimed to find out the drought characteristics and driving factors of grassland in Qinghai Province. The grassland coverage area in Qinghai Province was selected as the sampling site. The temporal and spatial distribution characteristics and occurrence trend of grassland drought in Qinghai Province were evaluated according to the water balance and crop water requirement and the key driving factors of drought were explored. The results showed that: during the whole growing season, the grassland in the eastern agricultural area, the peripheral area of the Qinghai Lake and the Qilian mountain area maintained light drought and no drought. The serious drought areas were mainly distributed in the southern Qinghai Pastoral Area and some low coverage grassland areas. The spatial distribution of drought was low coverage grassland > medium coverage grassland > high coverage grassland; the drought disaster type of grassland in the whole growing season was mainly light drought, followed by medium drought, the frequency of severe drought and special drought was low, and the intensity of extreme drought was increasing; precipitation and evapotranspiration played the largest driving role in the whole drought process, and they were all negative. With the aggravation of drought grade, evapotranspiration gradually replaced precipitation as the most important driving factor. On the whole, wind speed has a positive effect on drought, while temperature, sunshine hours, and water vapor pressure have little effect on drought. © 2019 Authors. All rights reserved.     

高寒草甸土壤物理特性和微生物数量对模拟践踏的响应

为探明高寒草甸土壤对家畜践踏的响应机制,于甘肃天祝进行了牦牛和藏羊的模拟践踏试验,研究了不同强度模拟践踏对土壤物理特性及微生物数量的影响。结果表明,0～10 cm土层的土壤紧实度和容重,随着践踏强度的增加均呈递增趋势;而呼吸速率和饱和导水率呈递减趋势。0～10 cm土层的3大微生物数量随践踏强度的增大而减小。同一践踏强度下,牦牛践踏后0~10 cm土层的土壤紧实度和容重均大于藏羊践踏处理;而饱和导水率、呼吸速率和微生物数量均小于藏羊践踏处理。综合分析认为,家畜的践踏强度越大,土壤的压实效应越显著;一个生长季的模拟践踏主要影响0～10 cm土层土壤的物理性质;且牦牛对土壤的压实效应和对微生物分布的抑制作用均大于藏羊。     

甘南牦牛养殖环境生态化治理问题思考

甘南州是甘肃省最主要的高寒草地畜牧业生产区域,甘南牦牛是当地最重要的家畜品种源。然而广大农牧民受靠天养畜观念的影响,传统落后的饲养管理方式未得到根本性改变,使得甘南牦牛养殖生态环境中依然存在诸多问题。甘南牦牛生产效率低,环境依赖性强,草场压力大、圈舍周边环境恶化等问题依然成为制约甘南牦牛产业化发展的瓶颈。文章针对以上突出问题进行分析,提出了甘南牦牛养殖环境生态化治理技术措施,进而促进甘南高寒牧区草地畜牧业发展方式转变,有效维护草地生态功能。     

西藏牦牛资源现状及生产性能退化分析

在了解目前西藏牦牛资源现状的基础上，根据牦牛畜群结构、生长发育状况、生产性能(产肉性能、产乳性能、产毛性能、繁殖性能)等状况，进行了全面而深入的调查、测试和分析，弄清各类群的品种特征，资源优势，产品质量，分析我区牦牛生产性能退化幅度及退化原因，提出了相应的防止退化措施，为西藏牦牛和草地等可更新资源有效利用和协调发展，充分发挥高寒牧区自然资源生产潜力，改善生态环境和维护生态平衡，持续发展牦牛业及草地畜牧业提供依据。     

高寒混播草地放牧生态系统中牦牛生产和植被变化特征的研究

垂穗披碱草（Elymus nutans）/星星草（Puccinellia tenuflora）混播草地三个放牧季的牦牛放牧试验结果表明：①经过连续三个放牧季的放牧,放牧强度与物种丰富度、多样性指数H′、多样性指数D（除了2003年）和均匀度指数J′（除了2004年）均呈显著或极显著的二次回归;②随放牧强度的增加,各处理组地上生物量呈降低趋势,且草生长季节地上平均生物量与放牧强度之间呈极显著的线性回归关系,0~30 cm的地下生物量（包括活根和死根）与放牧强度之间呈二次回归关系;③牧草生长季牦牛最佳放牧强度为7.23头/hm2。     

青藏高原植被物候监测及其对气候变化的响应

研究青藏高原植被物候变化对揭示高寒生态系统对全球气候变化的响应机制具有重要的科学意义。本文选取1982-2005年的GIMMS NDVI遥感数据,采用动态阈值法提取了青藏高原高寒草地的物候信息,包括植被返青期、枯黄期及生长季长度,分析了青藏高原高寒草地植被物候的时空变化及其对气候变化的响应规律。研究结果表明,1)青藏高原植被物候多年均值的空间分布与水热条件密切相关。青藏高原从东南向西北,植被返青期逐渐推迟、枯黄期逐渐提前,生长季长度因受到植被返青和枯黄的影响,呈现逐渐缩短的趋势;2)植被返青期和枯黄期的年际变化整体上呈提前的趋势,生长季长度呈增长趋势;3)高原地区的植被物候易受到海拔的影响,但存在3400 m的分界线,在3400 m以下,物候随海拔变化的波动较大,而在3400 m以上,物候与海拔的关系密切;4)气象因子是不同草地类型植被物候变化的主要影响因素,与降水相比,植被物候期与温度相关程度更高。     

我国青藏高原地区牦牛草地放牧系统管理及优化

基于牦牛所处地理环境,即青藏高原的特殊性,以及牦牛放牧这一生产方式在该地区第一产业中的重要地位,国内外学者从牦牛放牧系统的管理出发,对该系统中各因子之间的相互响应进行了研究,主要包括当放牧制度不同时,系统中的初级生产力和次级生产力的表现特征。从不同放牧制度中草地和家畜的特征表现,再到人为管理对这两种生产力的影响,研究者通过对比和试验进行了系统优化方法的探索。笔者通过对现阶段已有的研究成果进行整理和分析,概括在不同的放牧管理方式下草地放牧系统中的牦牛在生产力水平方面的差异,以及草地对不同放牧强度的响应,探究青藏高原地区牦牛放牧方式如何影响草畜之间的互作关系。在此基础上,分析其在实际生产活动中存在的问题,以及如何通过改进管理制度优化生产的办法,并对牦牛放牧系统发展进行了展望。     

Seasonal changes in weight and body composition of yak grazing on alpine-meadow grassland in the Qinghai-Tibetan plateau of China

Forty-five male yaks (born April 2001) were studied to determine how seasonal changes on the Qinghai-Tibetan plateau affected BW and body composition. Thirty yaks were weighed monthly from birth to 26 mo of age to determine seasonal changes in BW. The remaining 15 yaks were allocated randomly to five groups (three yaks per group), designated for slaughter at 13, 15, 18, 22, and 25 mo to measure seasonal effects on body chemical composition. All yaks were grazed on the alpine-meadow grassland of the plateau without any supplementation. All BW and body composition data were calculated on an individual basis. Body weight and body composition data were both compared across seven growth periods spanning 2 yr and defined by season. From April (birth) to December 2001 of the first growing season, yak BW increased (P < 0.01); however, during the subsequent cold season (December 2001 to May 2002), BW decreased (P < 0.01). The second growing season ran from May 2002 (13 mo of age) to October 2002 (18 mo of age), and the second live weight-loss season ran from October 2002 until May 2003. The weight loss experienced by yaks during the first weight-loss season was 25.64% of the total weight gain in the first growing season. The weight loss experienced by yaks during the second weight-loss season was 29.73% of the total weight gain in the second growing season. Energy retention in the second growing season was 291.07 MJ, 50.8% of which was consumed during the subsequent cold season. Energy accumulation in the summer (from May to July) and fall (from July to October) of the second growing season did not differ (5.01 and 6.30 MJ/kg of EBW gain, respectively; P = 0.63). The energy mobilized during the second winter (from October 2002 to February 2003) was 16.49 MJ/kg of EBW, and in the second spring (from February to May 2003), it was 9.06 MJ/kg of EBW. These data suggest that the decrease in grazing yak BW during the first cold season is much less than during the second cold season, and that the energy content per unit of BW mobilized is greater (P = 0.02) in winter than in spring. Results from this study demonstrate highly efficient compensatory growth in grazing yaks following the first weight loss period during the first cold season. This benefit could be exploited by herders to improve yak production. Yaks may have developed a type of self-protection mechanism to overcome the long cold seasons in the Qinghai-Tibetan plateau.     

天祝县草地资源对白牦牛产业化发展的影响

天祝县是甘肃省重要的畜牧业基地,是白牦牛唯一产地。由于超载过牧,利用不合理,使得天然草原普遍退化,鼠虫害及毒草危害严重,可利用草地质量下降,面积缩小,不仅影响当地草地畜牧业生产,也制约了天祝白牦牛产业化发展。必须通过加强草原保护与建设、扩大人工草地种植面积、加强白牦牛保种选育、提高白牦牛改良选育水平等措施和手段,才能使天祝的畜牧业生产走向持续、稳定和良性循环的轨道,也才能使天祝的白牦牛生产真正走向产业化。     

Prevalence and risk factors for brucellosis in domestic yak Bos grunniens and their herders in a transhumant pastoralist system of Dolpo,Nepal

Disease caused by Brucella spp. represents the most common bacterial zoonotic infection worldwide. The distribution and public health impact of these infections in Nepal's mountain regions are poorly characterized. This cross sectional study assesses the burden of brucellosis on transhumant pastoralists and their yak in and around Shey Phoksundo National Park, Nepal. Objectives were to: (1) estimate individual animal prevalence of Brucella-seropositive yak, (2) identify herd- and individual-level risk factors associated with Brucella seropositivity in individual yak, and (3) identify herd-level risk factors associated with reported human brucellosis-like symptoms in a household. A case of household symptoms was defined as the reported occurrence within the previous year of at least one of three acute symptoms (chills, fever, night chills) and one of two chronic symptoms (joint pain, swollen joint(s)) in one or both of two individuals interviewed in a household. Two-hundred-ninety-seven yak from 61 herds were sampled, and 61 household questionnaires were completed. Estimated true prevalence was 0.22 (95% CI: 0.17; 0.28). Poisson regression with generalized estimating equations was used to account for repeated measures within a cluster (herd). Yak in herds reporting abortion occurrence within the previous year were 2.3 times more likely to be seropositive than those in herds not reporting abortion (95% CI: 1.2; 4.2, p = 0.01). For every 10 animal increase in herd number, individual animal seropositivity risk increased by 30% (95% CI: 10%; 50%, p = 0.001). Male yak were 0.7 times as likely to be seropositive as female yak (95% CI: 0.5; 0.9, p = 0.01). Three to five year old yak were 2 times more likely to be seropositive than yak <3 years old (95% CI: 1.3; 3.2, p = 0.003), and yak >5 years old were 4.9 times more likely to be seropositive than yak <3 years old (95% CI: 2.9; 8.1, p < 0.001). Risk of reported brucellosis-like symptoms at the household level was 2 (95% CI: 1.1; 3.5, p = 0.02) times greater for households with herds with >1 reactor, and was 3.6 (95% CI: 1.4; 9.2, p = 0.008) times greater for households reporting the practice of raw milk consumption. These results indicate that yak seropositivity for Brucella spp. is widespread in the region, and is associated with reported human disease. This epidemiologic understanding is essential to the identification of public health opportunities at the interface of Himalayan livestock populations and the transhumant pastoralists that depend on them.     

牦牛和藏羊混合放牧对放牧家畜采食量和植物补偿性生长的影响

为探究放牧方式对青藏高原高寒草地家畜的采食量和植物补偿生长的影响,本试验在环青海湖流域高寒草地设置放牧方式（牦牛单独放牧、藏羊单独放牧、牦牛和藏羊1：2混牧、牦牛和藏羊1：4混牧、牦牛和藏羊1：6混牧）控制试验,以期确定草地的承载力,并为制定合理的草地管理措施提供依据。试验结果表明：在群落水平上,家畜的采食量在藏羊（Ovis aries）单独放牧以及牦牛（Bos grunniens）与藏羊1：2混牧方式下,显著高于其他方式（P<0.05）;在功能群水平上,藏羊单独放牧与牦牛和藏羊1：2混牧这2种放牧方式下家畜对豆科植物的采食量较高;藏羊单独放牧与牦牛和藏羊1：2混牧植物的补偿生长能力显著高于其他放牧方式（P<0.05）。研究表明：藏羊单独放牧时,其采食量最高;牦牛和藏羊1：2混牧的放牧方式对植物补偿性生长的促进作用最明显。因此,从放牧家畜采食量与植物补偿生长两方面考虑,在青藏高原高寒草地藏羊单独放牧与牦牛和藏羊1：2混牧的放牧方式较为合理。     

Yak Dung Deposition Affects Litter Mixing Effects on Mass Loss in Tibetan Alpine Grassland

Plant litter and livestock excreta are two important ways of carbon and nutrient input to soil in grassland grazing systems. Grazing livestock often deposit dung on plant litter, which may affect litter decomposition through a changing microenvironment. We assessed effects of yak dung on litter mixing effects on litter decomposition in a Tibetan alpine grassland. Six common species were selected, including low-quality litter species Kobresia capillifolia, Elymus nutans, and Ligularia virgaurea and high-quality litter species Anemone rivularis, Saussurea nigrescens, and Thermopsis lanceolata. Litter bags containing each species alone and all two-species combinations were allowed to decompose with and without experimental dung addition in the field. Mass loss of the leaf litter was measured after 6 and 12 mo. High-quality litter species had significantly greater mass loss than low-quality litter species. Dung significantly accelerated litter mass loss after both 6 and 12 mo for low-quality litter species, but only after 12 mo for high-quality litter species. Litter mixtures containing both high- and low-quality species showed positive nonadditive effects (NAEs) on mass loss after 6 mo but additive effects after 12 mo. Dung increased the strength of NAEs after 6 mo and shifted litter mixing effects from positive to negative NAEs after 12 mo. Our results support previous findings that litter mixing could produce NAEs on litter decomposition and that these NAEs could change with incubation time. Most importantly, we show that dung can modify NAEs, demonstrating that litter mixing effects are dependent on the microenvironment. Our findings also demonstrate that yak dung can influence soil processes by varying both single-species litter decomposition rates and litter interactions within mixtures. Furthermore, the results suggest yak dung is closely related to material and nutrient cycling, so we believe dung should remain and not be substantially removed from this grazing ecosystem.     

青藏高原牦牛奶产业发展的现状及问题——基于那曲市的调研

牦牛奶产业是青藏高原巩固脱贫攻坚、实现畜牧产业良性发展的重要选择,政府、企业和牧户等多元主体在推动产业链建设上发挥着不同作用。本研究以那曲市色尼区为例,通过实地调研发现,龙头企业成为牦牛奶价值增值的关键主体,养殖合作社成为牧民增收的重要载体,供销合作社成为市场发展的重要补充,牧户在牦牛奶产业发展中显著受益,农村基层组织建设管理水平明显提高。当前,那曲牦牛奶产业存在产业发展初级、产品同质竞争、草原过载过牧、合作社管理不规范、行政干预过多以及食品安全风险等问题。基于牦牛奶产业对青藏高原可持续发展的战略地位,下一步应通过加强基础研究和科技投入、积极引育管理人才、完善产业链利益联结机制、厘清多元主体职责定位等,推动当地牦牛奶产业健康可持续发展。     

Factors affecting the livestock herd size among smallholder households in Zambia

Structural changes in the economic and demographic landscapes in the developing countries create a host of opportunities for smallholder livestock producers to tap into the economic growth from which they have largely been excluded. However, small livestock herd sizes limit the opportunities available to farmers to commercialize and benefit from the growing demand for livestock and livestock products. Therefore, understanding what it takes to build and maintain the herd size is a critical step in addressing the problem of low market participation. The study used five cross-sectional nationally representative data sets to arrive at the following conclusions. While purchases are a primary source for the initial stock, births are the principal way of increasing the herd size. Livestock deaths as reflected by high mortality rates are the major outflow channel through which livestock leaves the herd, and reducing the mortality rates has a positive effect on the livestock population as evidenced within the cattle sub-sector. Thus, provision of adequate animal health services is key to addressing the high mortality rates which subsequently can lead to increased herd size. As births are the primary means of increasing the herd size, it is necessary to implement interventions that address the reproduction rates. The interventions include adequate feeding of livestock on high-quality feed and strategic feeding to address the dry season challenges. These interventions can facilitate the growth of the young livestock into mature breeding stock and thus increase the herd size.     

Great Changes in Production System of Yak

Since the time that yaks were domesticated, due to the special social, natural and economic conditions ,and yaks own biological and economic characteristics, the Yak Production System has been formed, which is different from other livestock production systems. The system has the characteristics of unique breed, herding perennially on grassland and a variety of products. It is a low-efficiency system with the low-cost,low-production,long-cycle and slowfunction. Based on the experiments and research,exercising the measure of stopping milking and mainly producing beef,it's the redisposition of resources and the combination of multi-superiority. By the scientific management, the superiority of grass growing in warm season, the dominant position of total nutrition of mother milk, the superiority of calves developing in early days and the genetic preponderance of new breeds of yak are perfectly integrated. It also got the economic, biological and ecological benefits.     

青海省"西繁东育"工程经济、生态效益核算

针对农民关心的经济收益问题,核算了"西繁东育"的经济收入;同时,参考Robert Costanza对全球自然生态系统服务价值的核算以及谢高地等对中国草地生态系统服务价值和青藏高原生态资产价值的评估,对"西繁东育"工程带来的生态效益进行估算.藏系绵羊羔羊、淘汰母羊和牦牛牛犊西繁东育为农民带来的经济收益分别为38.98,47.12元/只和212.6元/头,而因此产生的生态效益价值高达5 301.85元/个羊单位和15 953.31元/头,在青海实施"西繁东育"不仅可以增加农民经济收入,提高牧户抗灾保畜能力,因此而产生的生态效益也非常可观.