环青海湖地区天然草原生物量动态变化分析

本文通过海北牧业气象试验站1997~2004年牧草生物量测定资料,分析了环湖天然草原生物量动态变化。结果表明:分种牧草生物量年变化幅度大于牧草群体的变化;牧草生长季5种主要优势种牧草的生物量占总生物量的50%以上;牧草群体生物量年变幅范围在191.8~238.2g/m2之间。     

海北地区畜牧业生产与气象条件的关系分析

本文利用海北牧业气象试验站所观测的畜牧业资料和相对应时期的地面气象资料,分析了温度、降水等气象因子对本地区天然牧草的返青期、黄枯期、生物量、家畜膘情、家畜牧事活动等的影响。     

气象因子对典型草原地上生物量的潜在影响

利用锡林浩特国家基准气候站和牧业气象试验站2004—2018年牧草生长季气象资料和生态观测资料,分析了各气象因子对锡林浩特典型草原地上生物量在全生育期的潜在影响。结果表明:锡林浩特典型草原牧草地上生物量有明显增加趋势,增加速率为每年51.7kg/ha,相关系数0.459(P<0.05)。降水量与同期地上生物量干重呈极显著正相关,相关系数是0.525(P<0.01)。每增加1mm降水量使地上生物量增加3.5kg/ha。降水量在牧草全生育期是影响典型草原地上生物量最主要的气象因子。其它气象因子在全生育期对地上生物量的影响不显著。     

降水对青海环湖天然牧草生长的长期效应分析

选用铁卜加牧业气象试验站天然牧草历史观测资料,利用相关分析方法,探索天然牧草发育期、生长高度、覆盖度和产量等生长发育指标与前期不同时段降水量的相关显著性,模拟降水对天然牧草生长发育的长期效应。研究表明:无论是天然牧草的返青、开花、黄枯等发育期,还是5～7月牧草生长高度及月增加值和6～8月植被覆盖度,均与前期相关时段的降水量存在显著的相关性,从而对6～7月干草产量及其月增加量产生决定性的影响,充分说明降水对青海环湖天然牧草生长具有长期效应。     

气象条件对天山北坡中山带牧草生长发育及产量形成的影响

用1987～1990年乌鲁木齐牧业气象试验站天然牧草生育期和产量与气温、降水、日照时数观测资料,分析了气象条件对天然牧草生长及产量的影响,结果表明:不同品种牧草春季返青的温度指标不同,喜凉牧草为-1～-2℃,喜温牧草为4.6℃;黄枯期温度指标为6.3～9.1℃;热量条件可满足牧草生长发育及产量形成的需要;干草重与气象条件的相关性比鲜草重与气象条件的相关性好,不同要素中,降水量的相关性最好,积温居中,日照时数最差;用积温、降水量及日照时数可预测天然草场牧草干草重。     

玛沁县近20年高寒草甸植物物候变化特征

利用玛沁县气象局2003～2021年牧业气象观测站高寒草甸植物的物候资料及1961～2021年气象资料，分析了牧草返青期、开花期、枯黄期与气象因子的关系。结果表明：（1）近61 a来，玛沁县年平均气温以0.4℃/10 a的趋势升高，年降水量以9.7 mm/10 a的趋势增加，年日照时数以20 h/10 a的趋势减少。（2）牧草返青期平均日期为5月7日，平均开花日期为7月14日，平均枯黄日期为9月28日,平均生长期143 d。（3）牧草返青期和开花期呈不显著推迟趋势，枯黄期呈明显的推迟趋势，生长期呈延长趋势。（4）牧草返青期与4月中旬降水量呈负相关；牧草开花期与3月下旬气温呈负相关，与5月上旬气温正相关；牧草枯黄期与前期降水量和气温呈正相关。     

青海环湖地区天然牧草群体生长动态数值模拟

依据环湖地区中心的铁卜加牧业气象试验站观测资料，以设计土壤潜在吸水系数、土壤潜在吸水量、降水指数和水分订正系数的为基础，从农业气象角度出发，选择水分正系数对生长季大于或等于０℃的积温进行订正，得到气象积值，并根据数学生态学理论得出了环糊地区天然牧草群体生长动态数值模拟表达式。     

青海湖北岸天然草地牧草生长特征分析

利用青海湖北岸海北牧业气象试验站1997~2008年观测的天然牧草生长特征资料,分析了近12a来该区域牧草生育期、高度、盖度、产量等变化规律。结果表明:除猪毛蒿返青、开花期推迟外,其余牧草返青和开花期均提前;除矮生嵩草外,其余牧草黄枯期推迟,生育期延长;群落盖度呈下降趋势;虽然分种牧草高度和产量变化表现有所不同,但群落草层高度明显上升,总产量也呈增加趋势。说明在气候变化大背景下,青海湖北岸天然草地生态环境向好的方向发展。     

天山北坡中山带天然牧草对水分条件反应特性的分析

利用新疆乌鲁木齐市牧业气象试验站2004—2009年的气象和牧草资料,研究了降水、土壤水分等水分条件对天山北坡中山带乌鲁木齐南山草原5种优势天然牧草生长高度及产量形成的影响。结果表明：天山北坡中山带中老芒麦（Elymus sibiricus）、早熟禾（Poa annua）、黄芪（Astragalus hoantchy）、老鹳草（Gterantum pratense）、千叶蓍（Achillea millefoli-um）这5种天然牧草的生长高度和产量对水分条件表现出不同的反应,老芒麦最耐旱;早熟禾和千叶蓍的抗旱性相当;黄芪对水分条件的反应最为敏感。因此,大部分牧草产量形成需水临界期是6月。这对天山北坡中山带地区草地增水抗旱工作的时间安排具有指导作用。     

牧草物候特征对气候因子的响应

选取新疆乌鲁木齐市牧业气象试验站2004—2015年早熟禾（Poa annua）、黄芪（Astragalus membranaceus）、老鹳草（Geranium wilfordii）、老芒麦（Elymus sibiricus）、千叶耆（Achillea millefolium）5种天然牧草物候期资料和同期气象资料,采用统计分析法分析了物候期与气候要素间的关系。结果表明,5种牧草的返青期基本一致,开花期有提前有推迟,黄枯期普遍推迟,其中豆科牧草的黄枯期提前;气温是影响牧草春季物候期的重要因素,返青期和开花期的早晚与其前1~2个月气温的负相关程度较高,黄枯期与气温存在正相关,其中老芒麦的黄枯期与其前1~2个月的日照时数负相关程度较高。     

樱桃新梢与果实的生长发育动态及相关性研究

为了给红灯笼樱桃适时施肥和果实适期采收提供理论依据，并为制定科学的栽培技术和管理措施提供参考。定期调查4～5年生红灯笼樱桃新梢和果实生长发育动态及其相关性。结果表明：（1）新梢生长从3月上旬开始，一直生长到8月下旬停长，生长期达140天，在生长发育过程中出现一～四次生长高峰期，其中伸长生长一～四次，生长量四次，净生长量一次；叶片生长二～三次，生长量三次，净生长量二次；加粗生长四次，生长量和净生长量都四次。（2）果实生长从4月上旬为花谢幼果期开始,一直长到6月中旬停长期,生长期长达56～63天，果实纵横径在整个生长过程中出现次二～三次生长高峰期，其生长量三次；净增长量二～三次生长高峰：其中果实纵径二次；果实缝合线横径三次；果实非缝合线横径出现二次。（3）果实生长与新梢生长的相关性：果实生长量曲线和新梢生长量曲线都是逐步升高的单曲线，其新梢伸长生长和果实生长是一致的，呈双S曲线；果实净生长量有明显的二～三次生长高峰期，其生长曲线是S曲线或双S曲线，而新梢伸长生长的净生长量有一～四次生长高峰期，其中伸长生长是一次高峰，生长曲线呈凸曲线，加粗生长的净生长量有四次生长高峰期，其生长曲线呈三S曲线。（4）建议樱桃进行栽培管理时要求在头年加强水肥管理的同时，在4月下旬作为最佳施肥时期施肥，同时在果梢生长旺期加强根外追肥，来缓解养分的竞争。     

Empirical Growth Curve Estimation Using Sigmoid Sub-functions that Adjust Seasonal Compensatory Growth for Male Body Weight of Thoroughbred Horses

Thoroughbred horses are seasonal mating animals, raised in northern regions or countries. Foals born yearly in spring generally show a typical seasonal compensatory growth pattern, in which their growth rate declines in the first winter and increases in the next spring. In this study, a new empirical adjustment approach is proposed to adjust for this compensatory growth when growth curve equations are estimated, by using 1,633 male body weights of Thoroughbreds as an illustrating example. Based on general Richards growth curve equation, a new growth curve equation was developed and fit to the weight-age data. The new growth curve equation had a sigmoid sub-function that can adjust the compensatory growth, combined with the Richards biological parameter responsible for the maturity of animals. The unknown parameters included in the equations were estimated by SAS NLMIXED procedure. The goodness of fit was examined by using Akaike’s Information Criterion (AIC). The AIC values decreased from 13,053 (general Richards equation) to 12,794 (the newly developed equation), indicating the better fit of the new equation to the weight-age data. The shape of the growth curve was improved during the period of compensatory growth. The proposed method is one of the useful approaches for adjusting seasonal compensatory growth in growth curve estimations for Thoroughbreds, and for their management during the compensatory period. Based on this approach, the optimal growth curve equations can be estimated also for female body weight of Thoroughbreds or other growth traits affected by seasonal compensatory growth.     

Endocrine regulation of fetal and postnatal meat animal growth

Evidence is discussed which indicates that nutrient partitioning between muscle and adipose tissue can be altered by growth hormone administration in meat animals. In the limited number of studies conducted with meat animals, growth rate, feed efficiency and carcass composition were improved by growth hormone administration. When insulin was administered to normally growing swine no improvement in growth performance was observed. The mechanisms by which growth hormone affects growth performance are not clear but considerable data from rodent studies exist to indicate that many of the growth promoting effects of this hormone are due to somatomedins. However, few data are available for meat animals to indicate whether the growth promoting effects of growth hormone are mediated by somatomedins. Knowledge about the mechanisms that regulate growth hormone synthesis, secretion and biological action is accumulating. It is apparent that growth hormone administration induces an insulin-resistant state in rodents and meat animals. It is not clear whether chronic growth hormone administration in meat animals induces a growth hormone resistant state. Based on the available information, manipulation of systemic hormone concentrations and(or) tissue sensitivity to hormones involved in growth and differentiation may result in means to manipulate fetal and postnatal growth and development.     

内蒙古典型草原羊草生长高度研究

通过对内蒙古典型草原羊草的试验研究,得出羊草的旬生长高度与旬平均气温、旬降水量和土壤含水量相关密切,5～8月牧草每旬的生长高度与前一旬生长高度相关系数达0.964,羊草的生长符合线性生长规律。由于羊草在生长后期受到自身生长节律的影响,符合Logistic生长曲线的特征。在研究中建立了多元线性回归模型和Logistic生长曲线模型,并建立了生长高度预测模型。经拟合检验效果较好,预测模型能在一定精度水平上准确地预测羊草的生长高度。     

研究紫花苜蓿第1茬地上部干物质生长过程与有效积温的关系

对不同秋眠级数的4年生紫花苜蓿Medicago sativa品种第1茬干物质生长与≥5 ℃有效积温的研究结果表明：1）不同紫花苜蓿品种各器官干物质生长趋势一致,干物质生产潜力、最大生长速率、干物质生长盛期的平均生长速率均表现为全株＞茎＞叶,但是最大生长速率和平均生长速率所对应的有效积温值范围有差异。全株、茎和叶干物质最大生长速率分别出现在5 ℃初日后有效积温达504.72～609.45 ℃、574.47～643.91 ℃、444.53～543.25 ℃之时;平均生长速率转折点所对应的有效积温值范围为总干物质为384.61～716.54 ℃;茎干物质为424.48～773.36 ℃;叶干物质为320.42～642.48 ℃。2）不同苜蓿品种间干物质生长存在差异。半秋眠性品种路宝、牧歌401和美国杂交熊全株、茎、叶的干物质潜力大,最大生长速率较大,生长盛期内的平均生长速率较大,各转折点所对应的有效积温值相对较高,且其迟滞期的有效积温值也相对较高,秋眠性品种超级13R则相反。     

Predicting lean growth while accounting for correlated traits.

Lean tissue growth rate is usually estimated from indirect measurements including growth rate. A procedure to determine prediction equations for lean tissue growth rate is proposed. The procedure restricts the regression of fat growth rate on predicted lean growth rate to be equal to the regression of fat growth rate on actual lean growth rate. The restriction can be phenotypic or genetic if suitable parameter estimates are available. When applied phenotypically, selection on predicted lean tissue growth rate will result in selection differentials for both fat and lean tissue growth rates that are proportional to those obtained by direct selection for lean tissue growth rate. This restriction is desirable because expected correlated changes in fat are used to justify selection for lean tissue growth. Conventional prediction procedures have ignored correlated changes and obscured the original intent of using lean tissue growth rate as a biological selection criterion. When using conventional procedures to predict a biological selection criterion from indirect measurements, changes in important correlated traits may depend more on the choice of indirect measurements than on the choice of selection criterion.     

人工草地绵羊系统优化研究Ⅰ人工草地初级生产力

亚热带中、高海拔地区放牧人工草地牧草生长速率呈单峰曲线,高峰落在7月份,低谷为3～4月份,10月至第二年3月间为牧草低生长速率期,牧草生长速率起伏不定.在速生季,中海拔地区牧草生长速率较高海拔地区高,但在缓生季二者没有太大区别.     

羊草生长率的研究和生长率假说的验证

生长率假说（GRH）是研究生物生长率与化学计量特征之间关系的理论。为了验证生长率假说，以北方草原重要建群种羊草（Leymus chinensis）为材料，将取自内蒙古和吉林省4个地点的羊草在相同的光照、水肥条件下盆栽土培，用称重法测定了羊草的生长率，用PCR的方法分析了羊草核糖体DNA基因间隔区（IGS）长度，研究了羊草生长率与羊草磷含量、氮磷比、IGS长度及取样地土壤中氮、磷含量之间的关系。结果表明，羊草生长率与羊草全磷含量存在正相关关系，与羊草氮磷比存在负相关关系，生长率较高的羊草具有较长的IGS，符合生长率假说的预测。不同来源的羊草种植在相同环境下，来自氮、磷含量较高土壤的羊草具有较高的生长率，这可能是羊草对特定地域生境条件长期适应的结果。高的生长率和长的IGS可能是植物对较高氮、磷含量环境的适应。     

灌溉条件下不同紫花苜蓿品种生长动态模型及其类型

研究了灌溉条件下15个紫花苜蓿(Medicago sativa)品种二年龄第一茬草的生长动态,其动态模型符合Logistic生长曲线;各品种之间的回归模型有明显差别。依生长曲线方程计算了各品种的最高产量潜力(K),最大生长速度(Vmax)、生长最快时间(t)、生长速度由慢变快的突变点(t1)和由快变慢的突变点(t2)、旺盛生长期(t2-t1)和生长特征值(GT)。t2可作为刈割始期的指标,供生产中参考应用。对这些特征值进行了偏相关分析,表明苜蓿产量潜力的大小取决于旺盛生长期和最大生长速度二者的乘积。以这些特征值为依据进行了聚类分析,第二类品种(金皇后、巨人201、德宝、三得利、维拉和瑞西)表现良好,宜在当地推广种植,刈割始期为5月17日。     

Histomorphometric study of the goat stomach during prenatal development

The aim of this study was to perform a morphometric analysis of the different structural tissue layers of the goat stomach to study their prenatal growth from mathematical models fitted to these morphometric data. A total of 90 embryos and fetuses were used, from the early stages of prenatal life until birth. The growth rate of the gastric wall was slower than that of body length; rumen was the stomach compartment displaying slowest growth. In the three non‐glandular compartments, the epithelial layer grew faster than the gastric wall itself, while the growth rate of the abomasal epithelium declined in the early stages of development. A decline in growth rate was also observed for the lamina propria and submucosa in rumen and reticulum from the early embryonic stages, whereas in omasum and abomasum these layers continued to grow as gestation progressed. The tunica muscularis displayed consistent growth in all compartments, growing faster than the gastric wall. Serosa thickness increased as gestation progressed, displaying a decline in growth‐rate only in the omasum. In conclusion, the dynamics of gastric wall growth were governed by the growth rate of each of the component tissue layers.