Spectrophotometry of Artemisia tridentata to Quantitatively Determine Subspecies

Ecological restoration is predicated on our abilities to discern plant taxa. Taxonomic identification is a first step in ensuring that plants are appropriately adapted to the site. An example of the need to identify taxonomic differences comes from big sagebrush (Artemisia tridentata). This species is composed of three predominant subspecies occupying distinct environmental niches, but overlap and hybridization are common in ecotones. Restoration of A. tridentata largely occurs using wildland collected seed, but there is uncertainty in the identification of subspecies or mix of subspecies from seed collections. Laboratory techniques that can determine subspecies composition would be desirable to ensure that subspecies match the restoration site environment. In this study, we use spectrophotometry to quantify chemical differences in the water-soluble compound, coumarin. Ultraviolet (UV) absorbance of A. tridentata subsp. vaseyana showed distinct differences among A.t. tridentata and wyomingensis. No UV absorbance differences were detected between A.t. tridentata and wyomingensis. Analyses of samples from > 600 plants growing in two common gardens showed that UV absorbance was unaffected by environment. Moreover, plant tissues (leaves and seed chaff) explained only a small amount of the variance. UV fluorescence of water-eluted plant tissue has been used for many years to indicate A.t. vaseyana; however, interpretation has been subjective. Use of spectrophotometry to acquire UV absorbance provides empirical results that can be used in seed testing laboratories using the seed chaff present with the seed to certify A. tridentata subspecies composition. On the basis of our methods, UV absorbance values < 2.7 would indicate A.t. vaseyana and values > 3.1 would indicate either A.t. tridentata or wyomingensis. UV absorbance values between 2.7 and 3.1 would indicate a mixture of A.t. vaseyana and the other two subspecies.     

Fall Water Effects on Growing Season Soil Water Content and Plant Productivity

Understanding fall precipitation effects on rangelands could improve forage production forecasting and inform predictions of potential climate change effects. We used a rainout shelter and water addition to test effects of seasonal precipitation on soil water and annual net primary production of C₃ perennial grass, C₄ perennial grass, annual grasses, forbs, and all plants combined. Treatments were 1) drought during September−October and April−May (DD); 2) drought plus irrigation during September−October and drought during April−May (WD); 3) year-long ambient conditions (WW); and 4) ambient plus irrigation during September−October (W + W). Treatments created conditions ranking among the driest and wettest September−October periods since 1937. Fall water effects on soil water were not detectable by May at 15 cm and 30 cm. Effects persisted into July at 60 cm and 90 cm, depths below the primary root zone. With spring drought, annual net primary production was 344 kg ha⁻¹ greater when the previous fall was wet rather than dry. No differences were detected between fall water treatments when spring was wet and fall was about 184% (1 938 ± 117 kg ha⁻¹) or 391% of the median (1 903 ± 117 kg ha⁻¹). Fall water increased C₃ perennial grass when spring was also wet and had no effect under spring drought, when forage production concerns are greatest. Fall water did not affect C₄ perennial grass, and extremely wet fall conditions reduced forb production about 50%. The greatest effect of fall water was increased annual grass production. Even record high levels of fall water had minor effects on biomass, functional group composition, and soil water that were short-lived and overwhelmed by the influence of spring precipitation. Movement of fall water to deep soil by the growing season suggests plants that would most benefit from fall precipitation are those that could use it during fall (winter annuals), or deep-rooted species (shrubs).     

西藏3种蒿属植物营养成分与矿物质元素含量研究

本试验采用国标法对西藏3种蒿属植物藏沙蒿（Artemisia wellbyi）、大籽蒿（Artemisia sieversiana）和青蒿（Artemisia annua）的主要营养物质、氨基酸和矿物质元素含量进行测定。结果显示：3种蒿属植物的粗脂肪、粗蛋白、粗纤维、粗灰分含量差别较大,大籽蒿粗蛋白含量最高（3.34%）,青蒿最低（2.01%）,相互间差异显著（P<0.05）;矿物质元素含量差别也较大,常量矿物质元素中,三者均是钾含量最高,镁含量最低;微量矿物质元素中,三者均是铁含量最高,硒含量最低;3种植物均含有16种水溶性氨基酸,大籽蒿氨基酸总量最高（17.59%）,青蒿的最低（7.99%）。因此,在牧草匮乏季节,藏沙蒿、大籽蒿和青蒿均可作为西藏后备牧草,供牛羊等牲畜饲用,其中大籽蒿营养价值更为全面。     

Effects of a Companion Plant on the Formation of Mycorrhizal Propagules in Artemisia tridentata Seedlings

Inoculation of seedlings with arbuscular mycorrhizal fungi (AMF) can increase their establishment after outplanting. The success of this practice depends partly on the extent of root colonization and abundance of AMF propagules in the outplanted seedlings. We conducted a greenhouse experiment to investigate the effects of a companion plant, the native grass Poa secunda J Presl (Sandberg bluegrass), on the formation of spores and vesicles, AMF colonization, and AMF taxa present in the roots of the shrub Artemisia tridentata Nutt (big sagebrush). These effects were tested at two phosphorus (P) fertilization levels, 5 μM and 250 μM. Neither coplanting nor differences in P had an effect on spore density in the potting mix. In contrast, coplanting increased vesicular colonization of A. tridentata from 5% to 18%, but only at low P. Differences in P also affected vesicular colonization of P. secunda, which was 10% and 30% at high and low P, respectively. Arbuscular colonization of A. tridentata was not affected by the treatments and ranged between 12% and 20%. In P. secunda, arbuscular colonization was lower but increased from high to low P. Coplanted seedlings exposed to low P also had the highest levels of total AMF colonization, 70% for A. tridentata and 63% for P. secunda. On the basis of partial sequences of the 28S ribosomal RNA gene, coplanting did not affect the AMF taxa, which were within the Glomeraceae. In some taxa within this family, root fragments containing vesicles are the main propagules. Particularly in this situation, increases in vesicle density caused by coplanting and low P are likely to facilitate mycorrhization of A. tridentata after outplanting, resulting in higher levels of colonization than those naturally occurring in the soil. Such outcomes are critical for assessing the extent to which A. tridentata establishment is limited by insufficient AMF colonization.     

Nondestructive Age Estimation of Mountain Big Sagebrush (Artemisia tridentata ssp. vaseyana) Using Morphological Characteristics

Current methods for determining plant age of shrub species require destructive sampling and annual growth ring analysis on the primary stem. Although individual plant ages can frequently be determined in this manner, the method is time consuming and of limited value for plants that have lost stem wood from stem splitting and rot. Nondestructive methods for estimating big sagebrush (Artemisia tridentata Nutt.) plant age would be useful in assessing stand age structure and population dynamics at variable spatial scales. The purpose of this study was to test a suite of traits for potential use in estimating mountain big sagebrush (Artemisia tridentata ssp. vaseyana [Rydb.] Beetle) age. We evaluated traits including plant height, crown area, subcanopy litter depth, percent crown mortality, bark furrow depth, bark fiber length, circumference and diameter of plant basal stem, and circumference of secondary and tertiary branches. We measured and harvested basal cross-sections from 163 plants of varying sizes from five locations in central and south-central Utah. Plant age was determined from annual growth rings. Linear regression analyses revealed that stem diameter (r² = 0.507 P < 0.0001) was the most highly correlated variable with plant age across all sites, followed by stem circumference (r² = 0.474 P < 0.0001), secondary branch circumference (r² = 0.360, P < 0.0001), tertiary branch circumference (r² = 0.405, P < 0.0001), and bark fiber length (r² = 0.373, P < 0.0001). Results support previous findings that stem girth has value for estimating mountain big sagebrush plant age and that this trait is a better indicator of age than any other tested traits. Although the relationship between stem diameter and plant age was significant, substantial stem size variability associated with plants of the same approximate age indicates that the method is most appropriate when precise age estimates are not required. This technique was developed specifically for mountain big sagebrush, but it is expected that it can be adapted for other sagebrush taxa.     

典型草原植物养分对生长季不同放牧强度的动态响应

为阐明典型草原生长季放牧过程中植物养分的动态变化,本研究在2017年生长季的不同放牧阶段(放牧早期、放牧中期和休牧后)对不同放牧强度影响下内蒙古典型草原主要物种克氏针茅(Stipa krylovii)、羊草(Leymus chinensis)和糙隐子草(Cleistogenes squarrosa)的碳(Carbon,...     

松嫩平原艾蒿无性系种群根茎的年龄结构研究

将艾蒿根茎划分为不同年龄级,按长度和生物量统计其年龄结构,分析各龄根茎数量特征的变化规律.结果表明:艾蒿根茎的最大存活年龄为4龄;其根茎长度年龄结构为增长型;生物量年龄结构为稳定型;开花期根茎累积长度为6984.8 cm·m-2,根茎生物量为103.7 g·m-2;单位长度根茎的干物质贮存量随着龄级的增加而不断增大;高龄根茎具有较强的生活力;根茎长度比根茎生物量具有更大的生态可塑性.     

Genetic and phenotypic parameters for dietary selection of mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana

The heritability of diet selection for mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana [Rydb] Beetle) by grazing sheep was estimated from fecal samples collected from 549 Rambouillet ewes. Fecal samples were collected in September and October during 1996 and 1997 from free-grazing ewes on intermountain sagebrush-bunchgrass rangelands at the U.S. Sheep Experiment Station in Idaho. The total number of fecal samples was 1,949. Fecal samples were evaluated for composition of big sagebrush by near-infrared spectroscopy. Percentage of sagebrush in the diet was less in September than in October (21.6 vs 31.7%, respectively). Single-trait and bivariate derivative-free REML analyses were performed to genetically compare percentage of sagebrush in the diet in September and October. Heritability estimates were similar between September and October measurements (0.25 and 0.28, respectively). The genetic correlation between September and October percentages of sagebrush in the diet was high (0.91), implying that there is strong genetic similarity between September and October measurements and that an annual measurement may be sufficient for selection. These results contribute to a greater understanding of dietary preferences in freely grazing sheep, and suggest opportunities to improve production efficiency and forage management through selection for dietary preferences.     

海北高寒草甸植被在生长期辐射能量收支探讨

在晴天,海北高寒草甸植被辐射的各收支项均有明显的日变化规律,在中午13～14h最大。地表净辐射通量日变化在-158～499W·m^-2,8～9h到18h地表面净得到热量,地表处于吸热阶段,18h～翌晨8h区域净损失热量。反射率在早晨与傍晚最高,13h左右最低。植物生长季的4～9月,中午反射率约在0.20～0.22,早晨与傍晚在0.24～0.49,不同季节的3d日平均反射率为0.25,11h～15h平均为0.21。     

玉米皮对生长肉兔的营养价值评定

本试验旨在评定玉米皮在生长肉兔上的营养价值。选取32只35日龄体重相近[(760.33±48.29)g]的断奶新西兰白兔,随机等分为4组,每组8个重复,每个重复1只。各组分别饲喂基础饲粮和3种测试饲粮。测试饲粮分别由20%的3种不同来源的玉米皮与80%的基础饲粮混合而成。消化试验共15 d,其中预试期11 d,收粪期4 d。结果表明:1)不同来源对3种玉米皮总能(GE)和主要养分含量均有极显著影响(P<0.01)。3种不同来源玉米皮的GE及粗蛋白质(CP)、粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、酸性洗涤木质素(ADL)、粗脂肪(EE)、粗灰分(Ash)、钙(Ca)、总磷(TP)和无氮浸出物(NFE)含量平均值分别为19.84 MJ/kg、10.54%、16.32%、75.32%、20.23%、2.18%、5.54%、1.12%、0.49%、0.05%和66.48%。除半胱氨酸(Cys)、赖氨酸(Lys)和酪氨酸(Tyr)外,不同来源对3种玉米皮的其他氨基酸含量也有显著或极显著影响(P<0.05或P<0.01),3种不同来源玉米皮的精氨酸(Arg)、组氨酸(His)、异亮氨酸(Ile)、亮氨酸(Leu)、Lys、蛋氨酸(Met)、苯丙氨酸(Phe)、苏氨酸(Thr)和缬氨酸(Val)含量平均值分别为0.45%、0.43%、0.37%、1.31%、0.40%、0.12%、0.53%、0.52%和0.58%。2)不同来源对3种玉米皮的GE、DM、CP、ADL、Ca、TP、NFE的表观消化率有极显著影响(P<0.01)。3种不同来源玉米皮的GE、DM、CP、CF、NDF、ADF、ADL、EE、Ash、Ca、TP和NFE表观消化率平均值分别为33.32%、34.01%、70.54%、13.53%、20.07%、10.48%、-0.74%、85.49%、47.42%、29.02%、26.48%和23.81%。除Thr、Val、天冬氨酸(Asp)、甘氨酸(Gly)和丝氨酸(Ser)外,不同来源对3种玉米皮的其余氨基酸的表观消化率均有显著或极显著影响(P<0.05或P<0.01),氨基酸的表观消化率平均值均超过60%。由此可见,对于生长肉兔,玉米皮具有较高的营养价值,但不同来源玉米皮的营养价值有一定差异。     

干旱季节日粮中添加益生菌和过瘤胃脂肪酸对饲喂玉米青贮料生长山羊平均日增重和瘤胃代谢的影响

本试验目的在于调查添加益生菌、棕榈油过瘤胃脂肪酸(POBF)和益生菌 POBF对饲喂玉米青贮料的生长山羊平均日增重和瘤胃代谢影响.试验选用了27只约5月龄、体重(13.4±1.3)kg杂交生长山羊(Thai native×Anglo-Nubian),根据完全随机因子试验方法分成9组,进行10周饲养试验.POBF包含0、20和40 g/(goat·d)3个水平,益生菌包含0、2.5和5.0 g/(goat·d)3个水平.结果表明:POBF显著地降低日均干物质采食量(DMI)(P<0.05),益生菌提高DMI(P<0.05),20 g/(goat·d)POBF 益生菌[2.5和5.0 g/(goat·d)]不影响DMI(P>0.05).益生菌和益生菌 POBF显著提高平均日增重(ADG)(P<0.05).益生菌极显著地提高DM和OM消化率(P<0.01),POBF 益生菌显著提高DM和OM消化率(P<0.05).POBF、益生菌、POBF 益生菌均提高CP消化率(P>0.05).益生菌和POBF 益生菌显著提高NDF消化率(P<0.05).益生菌、POBF和益生菌 POBF极显著提高挥发性脂肪酸总量(P<0.01)和丙酸百分比例(P<0.05),降低乙酸百分比例(P>0.05).本试验结果证明:益生菌和POBF都能提高饲喂玉米青贮料的生长山羊ADG和瘤胃代谢水平,添加2.5 g/(goat·d)益生菌和20 g/(goat·d)POBF效果较好,同时添加2.5 g/(goat·d)益生菌和20 g/(goat·d)POBF效果最佳.     

葵花籽粕和花生壳在生长兔上的营养价值评定

为评定葵花籽粕和花生壳在生长兔上的营养价值,本试验选择18只110日龄平均体重(2.34±0.16) kg的白色獭兔,随机分为3组,每组6个重复.试验饲粮用套算法进行配制,葵花籽粕和花生壳的替代比例为20％;采用全收粪法进行消化试验,预试期和正试期各5d.结果表明:1)葵花籽粕和花生壳中的总能(GE)以及干物质(DM...     

三种生长调节剂对高羊茅生长特性及赤霉素含量的影响

通过盆栽方法测定植物生长调节剂对高羊茅(Festuca arundinacea Schreb.)草坪草株高、叶宽、叶绿素含量及赤霉素含量的影响.施用多效唑、矮必施和乙烯利3种生长调节剂,各设3个浓度梯度,分别为多效唑150 mg/L、200 mg/L、250 mg/L,乙烯利1000 mg/L1、200 mg/L、1400 mg/L,矮必施200 mg/L2、50 mg/L3、00 mg/L.结果表明:施用多效唑、矮必施和乙烯利降低了草坪高度,其中以250 mg/L多效唑、1200 mg/L乙烯利和300 mg/L矮必施效果最好;3种植物生长调节剂均能对高羊茅叶片的宽度产生影响,多效唑和矮必施促使叶片变窄,而乙烯利初期使叶片变宽,后期变宽效果消失;多效唑和乙烯利都不会对高羊茅草坪的颜色产生影响,矮必施在施药后前2个星期使叶色变深,第3星期后影响逐渐消失;多效唑、乙烯利和矮必施均能促使高羊茅体内赤霉素的含量降低,降低幅度达到30.6%~64.0%.综合考虑,高羊茅草坪施用250 mg/L浓度的多效唑时效果最好.     

Endocrine Changes and Their Relationships with Body weight of Growing Yak

Concentrations of growth hormone (GH), insulin, thyroxin(T4 ) and 3,3 ' 5 '-tri-iodothyronine (T3)in blood samples of growing yak during different seasons were determined by radio-immunoassay.Changes in bodyweight of the growing yak and compositions of grass were also measured. The seasonal changes in hormones were significant (at least P＜0.05). In the same season, variation in hormonal concentration was affected by the growth stage of the animal. The bodyweight gains varied in different seasons, with significant increase from May to September and decrease from January to May. Correlation analysis indicated that T4 had a significant positive correlation with bodyweight of the growing yak(r= 0.323,P＜0.05) ,but other hormones did not have significant correlations with bodyweight. The results show that annual cycle of weight loss and gain is attributable to the seasonal changes in feed supply and that the seasonal changes in the concentrations of the assayed hormones were indirectly dependent on grass growth.     

放牧藏羊冷季营养调控试验报告

藏系绵羊在产羔后分为4组,进行为期90天的补饲试验,结果:试验1组只均日补饲优质青干草0.5 kg,母羊和羔羊的增重分别为1.57kg和5.29kg;试验2组只均日补饲精料0.25kg,母羊和羔羊的增重分别为2.36 kg和7.9kg;试验3组只均日补饲精料0.5kg,母羊和羔羊的增重分别为4.25 kg和10.02kg;试验4组只均日补饲营养添砖0.15kg,母羊和羔羊的增重分别为1.7kg和6.51kg。4个试验组均达到了母羊保膘和羔羊成活的目的。其中,第3组母羊和羔羊的增重最高,饲料成本也最高;第1组母羊和羔羊的增重最少,但补饲成本最低。     

末茬紫花苜蓿套作饲用燕麦的种植模式研究

以末茬紫花苜蓿（Medicago sativa L.）套种饲用燕麦（Avena sativa L.）的牧草种植模式为对象,试验采用裂区设计,测定紫花苜蓿行距为30 cm和40 cm、燕麦播种日期为苜蓿第二茬刈割后7天和11天、燕麦播种品种为早熟品种（领袖）和晚熟品种（贝勒）的生长特性和产量,分析0~10 cm,10~20 cm,20~30 cm土壤的常规理化性质和有机碳含量,研究紫花苜蓿套种饲用燕麦的种植模式对植物生长、生产、土壤养分的影响,为选择合理的套作模式提供理论依据。结果表明：以苜蓿行距40 cm、苜蓿二茬刈割后第7天播种早熟品种燕麦的种植模式,与其他模式相比,能够极显著地降低0~10 cm,10~20 cm土层的pH值（P<0.01）,极显著地增加各土层土壤全氮、全磷、速效磷、速效钾、有机碳的含量（P<0.01）,而株高、生长速率、存活率、返青率与单作相比差异不显著（P>0.05）;合理的间套作模式（包括时间和密度）,将有利于土壤养分和饲草产量的增加,且有机碳可以作为评价套作系统土壤肥力的指标。     

玉米秸和大豆秸对生长獭兔的营养价值

为评定玉米秸和大豆秸在生长獭兔上的营养价值,本试验选择18只60日龄平均体重(1.78±0.20)kg的健康白色獭兔,随机分为3组,每组6个重复,每个重复1只。基础饲粮用套算法进行配制,玉米秸和大豆秸的替代比例为15%;采用全收粪法进行消化试验,预试期和正试期各7 d。结果表明:1)玉米秸与大豆秸中的总能(GE)以及干物质(DM)、粗蛋白质(CP)、粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、酸性洗涤木质素(ADL)、粗脂肪(EE)、粗灰分、钙(Ca)、磷(P)、无氮浸出物(NFE)含量分别为15.79 MJ/kg、90.06%、5.35%、34.74%、65.39%、37.43%、2.89%、0.88%、8.85%、0.50%、0.08%、40.26%与15.11 MJ/kg、91.39%、5.64%、47.11%、65.20%、50.10%、10.95%、1.05%、8.80%、0.42%、0.09%、28.80%;2)玉米秸和大豆秸在生长獭兔中的表观消化能分别为6.84和4.87 MJ/kg,生长獭兔对玉米秸与大豆秸中的GE、DM、CP、CF、NDF、ADF、EE、粗灰分、Ca、P、NFE的消化率分别为43.33%、34.44%、54.77%、21.02%、27.52%、23.58%、85.92%、45.47%、32.78%、60.05%、53.79%与32.18%、21.74%、50.72%、15.60%、19.78%、12.57%、87.16%、56.69%、36.00%、66.64%、34.93%。生长獭兔对玉米秸和大豆秸中的不同营养成分消化率存在一定差异,结合饲料原料营养物质含量总体分析,玉米秸对生长獭兔的营养价值要高于大豆秸。     

季节对育成母牛产粪量及粪污染物排放量的影响

选择健康状况良好、体重相似、出生日期相近的中国荷斯坦育成母牛5只作为试验对象,采用全收粪法研究育成母牛在一年四季中产粪量及粪污染物（N、P、Cu、Zn和有机质）排放量的变化情况及其规律.结果表明：不同季节间育成母牛产粪量与粪样中机质及N、P、Cu、Zn污染物的排放量均存在着极显著（P＜0.01）或显著（P＜0.05）的差别,因此,根据不同季节产粪量及粪中污染物排泄规律来研究配置符合育成母牛的均衡饲料配方,可达到既满足育成母牛的生产需要,又能最大限度地降低污染物排放量,减少奶牛场污染的目的.     

复合益生菌和纤维素酶发酵对艾草营养品质和微观结构的影响

本试验旨在研究复合益生菌和纤维素酶发酵对艾草化学成分、活性成分、发酵品质以及微观结构的影响,并研究其适宜发酵时间。以全株艾草粉(70%)和混合饲料(30%,由80%的玉米、10%的麸皮和10%的葡萄糖组成)为发酵底物,按照不同处理方式分为4个组,其中对照组不添加其他物质,复合益生菌组添加1%复合益生菌(含干酪乳杆菌1.0×10^6 CFU/mL、产朊假丝酵母菌1.0×10^8 CFU/mL和枯草芽孢杆菌1.0×10^6 CFU/mL),纤维素酶组添加1%纤维素酶(滤纸酶活力为130 FPU/g),菌酶联合组同时添加1%复合益生菌和1%纤维素酶,每个组设3个重复。将发酵底物混合均匀后,按照固体∶蒸馏水=5∶3(质量比)的比例添加蒸馏水,高压灭菌后进行发酵,发酵时长为7 d。结果表明:1)与对照组相比,单独添加复合益生菌除显著降低了艾草中半纤维素的含量(P<0.05)外,对其他各项纤维成分的含量无显著影响(P>0.05);单独添加复合益生菌、纤维素酶以及二者联合添加显著降低了艾草中中性洗涤纤维和半纤维素的含量(P<0.05);单独添加纤维素酶以及与复合益生菌联合添加均显著提高了艾草中粗蛋白质的含量(P<0.05),且菌酶联合组粗蛋白质含量显著高于其他各组(P<0.05)。2)与对照组相比,纤维素酶组与菌酶联合组艾草的pH显著降低(P<0.05),可溶性碳水化合物含量显著升高(P<0.05);菌酶联合组艾草中总黄酮和多酚含量显著升高(P<0.05)。3)纤维素酶组和菌酶联合组艾草表面微观结构显示凹凸不平,出现了大面积的破碎。4)菌酶联合组发酵第4天时,艾草中枯草芽孢杆菌、干酪乳杆菌和产朊假丝酵母菌的活菌数以及总黄酮和多酚含量均处在较高水平,其中产朊假丝酵母活菌数和总黄酮含量显著高于其他发酵时间(P<0.05)。由此得出,复合益生菌与纤维素酶联合添加显著降低艾草的pH,显著提高了可溶性碳水化合物、总黄酮和多酚的含量,改善了艾草的微观结构。复合益生菌和纤维素酶联合添加时艾草的适宜发酵时间为4 d。     

不同季节与年龄对肉鸽繁殖性能的影响

1999年以来,我场对引人种鸽在引种驯化和生产中4300对以上种鸽的产蛋、受精、孵化情况进行记录与统计,通过对自然育雏情况下的生产进行统计分析,以指导种鸽与乳鸽的生产计划、种鸽的更新、后备鸽储备,优化种鸽生产性能.……