影响精液质量的几个冷冻技术因素

本文提出冷冻精液生产工艺的技术关键是由冷冻温度和降温速度所构成的精液冷冻温度曲线，通过对国内１５个省，市级牛冷冻精液生产单位的生产工艺程序进行监测，对细管型及颗粒型精液冷冻温度曲线的类型，存在的问题及其影响因素进行了分析研究，提出了提高牛冷冻精液质量的建议。     

玉米秸秆中棉籽壳的含量对平菇产量的影响

利用玉米秸杆-棉籽壳基质栽培平菇，菌丝生长速度快，满袋时间比棉籽壳提前6d，子实体生长符合指数增长曲线，子实体生长速度的高峰期比棉籽壳滞后，出菇期比棉籽壳长。采用玉米秸杆和棉籽壳按1∶1混合袋栽平菇，生物学效率可高达138%。投入产出比为1∶2.46。     

聚类分析方法在鸡产蛋曲线中的应用

本文讨论了有序样品聚类方法在鸡产蛋曲线中的应用,并对尼克鸡300日龄内,每10天平均产蛋数进行合理分类。结果表明,该方法能较准确地对各产蛋期分类,这对生产性能分析,以及加强饲养和管理十分有益。对尼克鸡产蛋期分类结果表明,以6类或7类为最佳。     

豫西山区日本落叶松人工林立地质量评价

根据优势木高度与立地质量的关系及优势木高分面扇形法则等基本原理，采用一元非线性回归，多元数量化回归模型Ｉ等基本方法，编绘了豫西日本落叶松人工林地位指数级表和地位指数级曲线图，拟定了优势木高对立地因子的多元线性回归方程。在研究方法上综合地位级法及立地指数法的优缺点，将其改为地位指数法是本研究的一个特色。     

京白商品蛋鸡胫长的标准曲线

胫长是鸡的骨架发育的重要指标,通过对京白商品蛋鸡生长期胫长的测量和分析,拟合了一条标准曲线,并制定出1～140日龄的胫长标准值.     

宁夏引黄灌区盐渍化土壤在改良剂作用下的水力特性试验

为了研究宁夏引黄灌区盐渍化土壤在施加有机改良剂和无机改良剂后的水力特性,选取宁夏引黄灌区典型区域进行土壤改良并进行种植试验。将改良后的土壤分5层取样在实验室中进行土柱入渗试验,利用压力膜仪和自循环达西渗流试验仪,测量了土壤含水率与压力水头之间的关系和渗透系数;根据实测数据,选取van Genuchten （VG）模型进行参数反演,对不同改良剂处理后各层土壤水分特征曲线进行了对比分析。研究发现：①各层土壤在水吸力相同时,施加不同改良剂后的土壤含水率一般大于对照组,而有机改良剂处理组要大于无机改良剂处理组;②改良后水分特征曲线及相应VG模型中的参数发生了较大变化;③有机改良剂处理后土壤容重有所减小,而无机改良剂处理后土壤容重变化不太明显;④不同改良剂处理后土柱中水分入渗的湿润锋推进速度和土壤渗透系数有不同程度增大,有机改良剂处理组增大幅度大于无机改良剂处理组。综上所述,不同改良剂对土壤容重、含水率、水分入渗速度及其他水力参数都有较大影响,说明改良剂在一定程度上改变了土壤结构。土柱试验及种植试验均表明,有机改良剂（牛粪和糠醛渣）处理组的性态要优于无机改良剂（脱硫石膏和粉煤灰）处理组。     

转双价抗虫基因741杨根际致瘤农杆菌分离及生长曲线测定

应用稀释平血分离法对转双价抗虫基因741杨的根际土壤微生物进行了分离研究。对其中野杆菌属的致瘤农杆菌进行了筛选和鉴定,采用分批培养法测定其生长曲线。结果表明,该菌的生长曲线近似于“S”形曲线,其对数生长期的世代时间为44.3min。     

酶活梯度曲线法测定饲料中木聚糖酶的含量

试验选用加酶肉鸡全价料为样品,利用酶活梯度曲线法测定饲料中木聚糖酶的含量。结果表明:采用改进后的DNS法(即酶活梯度曲线法)测定饲料中木聚糖酶,可以显著提高检测的准确度;同时,此方法也为评定成品加酶饲料的品质提供了参考。     

Genetic characteristics of Japanese Holstein cows based on multiple-lactation random regression test-day animal models

The first three lactation curves of the Japanese Holstein cows were analyzed using a random regression (RR) test-day model with a cubic Legendre polynomial fitted to each of the three parities. The first three eigenvectors of the additive genetic RR covariance matrix explained 77.8, 10.9, and 4.2% of the total variance of the three parities and are associated mainly with the level of milk yield, the linear increase, and the concave curve, respectively. On a lactational basis, as the parity increases, the contribution of the first eigenvector to a lactational variation decreases whereas the contribution of the second eigenvector increases sharply. This means that the impact of the first eigenvector on the level of milk production decreases across parity whereas the effect of the second eigenvector on the shape of the lactation curve increases across parity. The first lactation curve was the most persistent, followed by the second and the third lactation. Persistency and days to reach peak yield decrease as the parity increases (45, 40, and 36 days for the first three parities). Daily heritabilities within lactation were lower for the first parity than for the second or the third parity. The first three lactation curves possess distinctive genetic characteristics that merit consideration when combining the proofs of the first three lactations to select for lifetime production. Within- and between-parity genetic correlations between the constant and the linear RR coefficients were all positive, suggesting that raising the level of milk production in one parity would increase the linear slope in all parities, thus improving persistency. Within- and between-parity genetic correlations between the constant and the quadratic RR coefficients were all negative, implying that increasing the level of production in one parity would deepen and/or widen the concave curve in all parities, thus decreasing persistency. The linear and quadratic RR coefficients were negatively correlated within or between parities and thus have antagonistic effects on persistency.     

实时荧光定量PCR检测猪细小病毒

根据已报道的猪细小病毒基因组序列,设计并合成了引物和探针,从猪细小病毒(PPV)感染的细胞中提取DNA,经PCR扩增,产物纯化后与pGEM-T-easy连接,转化大肠杆菌JM109,筛选后得到重组标准品质粒,对重组标准品质粒进行PCR和测序鉴定,表明目的片段已经成功克隆.将104～108拷贝反应的重组标准品质粒进行荧光定量PCR,系统自动分析软件显示Ct值与标准品浓度的对数之间存在良好的线性关系.动力学曲线分析表明,在该反应体系和反应条件下,标准曲线的灵敏度为102拷贝.本方法的建立为猪细小病毒感染的早期诊断奠定了基础.