Study on the Key Techniques of Rapid Propagation in Purebred Wagyu

In order to rapid propagation of purebred Wagyu, the experiment were conducted to study the effects of high intensity superovulation, embryo sex identification and different breeds recipient cattle on calving, gestation period and calf birth weight. Wagyu were superovulated repeatedly for nine times with a 30 days interval. The results indicated that the average number of total embryos collected at the second time was 22.78, which was significantly higher than those of the fifth to ninth times (P< 0.05),and there was no significant difference between the other groups (P> 0.05).There was no significant difference between the number of transferable embryos in the first to third times (P> 0.05). The available embryos number of the second times superovulation were significantly higher than those of the fourth to ninth times (P< 0.05),and were remarkably significantly higher than those of the seventh and ninth times (P< 0.01). There were no observably differences of pregnant rate and calving rate between sex identified embryos, and regular embryos respectively (P> 0.05).The female calf percentage of sexed embryos was 95.56%. The calving rate of the Simmental-catalo receptors were higher than those of Wagyu-catalo and Holstein receptors (P> 0.05). The gestation period of Wagyu-catalo were remarkably significantly greater than those of Simmental-catalo and Holstein receptors (P< 0.01), however, there was no significant difference between Simmental-catalo and Holstein receptors (P> 0.05). The birth weight of female calves calved by Simmental-catalo receptors were higher than those of Wagyu-catalo (P< 0.05), which was extremely significantly higher than those of Holstein receptor (P< 0.01). The male calf birth weight was no significant difference in the three breeds receptors (P> 0.05). There were obvious differences between male and female calves in gestation and birth weight with in the same recipient breed.     

影响中国美利奴羊(新疆型)羔羊初生重的非遗传因素分析

[目的]为了探讨主要非遗传因素对中国美利奴羊(新疆型)羔羊初生重的影响,收集2×104条中国美利奴羊(新疆型)羔羊鉴定记录.[方法]利用SAS8.1软件的GLM程序,分析出生类型、性别、群别、出生年以及月份对中国美利奴羊(新疆型)羔羊初生重的影响.[结果]公母羔的平均初生重分别为3.609和3.501 kg; 性别对羔羊初生重有极显著影响(P＜0.01);产羔数对羔羊初生重也有极显著影响(P＜0.01),单羔的初生重高于双羔.群别和出生年对羔羊初生重也存在着极显著影响(P＜0.01);出生月份对羔羊初生重无显著影响(P＞0.05).[结论]分析大量的记录资料讨论了出生类型等5个非遗传因素对中国美利奴羊羔羊(新疆型)初生重的影响,以期为今后估计美利奴羊遗传参数和育种值时固定效应的划分和选育提供一定的依据.     

英汉禁忌语比较

禁忌语是一种普遍的语言现象,几乎存在于日常生活的各个方面,世界各民族都有自己的禁忌语。东西方文化的差异决定了英汉禁忌语的异同,了解和把握这种差异,有利于跨文化交际。     

农业产业化的产生,意义及应注意的问题

着重探讨了农业产业化经营产生的历史背影及原因,农业产业化经营的理论支撑,实施农业产业化经 现实作用和深远意义以及在实施农业产业经营过程中应注意避免的倾向等问题。     

Fertility divergence across large and small areas

This paper examines U.S. female fertility during 2005–2019. Small areas had higher fertility rates than large metropolitan statistical areas (MSAs) during each year. Both experienced fertility declines between 2005 and 2019. However, decreased fertility was more pronounced for large MSAs, and the fertility gap between large and small areas widened considerably. Investigation by age group reveals that diverging fertility across large and small areas is driven by women ages 25–34. We also use multivariate regression analysis for ages 25–34 to consider relationships between individual-level and area-level characteristics and spatial divergence in fertility. Employment patterns, foreign-born status, and local housing costs are notable factors.     

我国生鲜类期货与现货价差的影响因素实证研究——以鸡蛋品种为例

生鲜类品种有着特殊的自然属性,其期现货价差也具有一定的特殊性.鸡蛋作为国内第一个上市的生鲜类期货品种虽然是可储存商品,但由于其特殊属性,在对鸡蛋期现价格关系的解释上传统的持仓成本理论并不适用.文章运用不可储存商品的期现价格关系相关理论,研究了鸡蛋期现货价差与饲养成本之间的关系.采用2015年1月1日-2019年12月3...     

池塘培育扣蟹技术研究

１９９３－１９９４年利用鱼池、稻田改造成的池塘培育中华绒螯蟹扣蟹，采取塑膜围栏防逃、调节水质、科学投饵、抑制幼蟹性腺发育等技术，５２亩鱼池改造池亩扣蟹１０５ｋｇ，规格１００只／ｋｇ；５９５亩稻田改造池亩产扣蟹５５ｋｇ，规格１８０只／ｋｇ。     

年龄、胎次、配种月份对奶牛产犊性别的影响

根据西宁某奶牛场1984-1995年荷斯坦奶牛的配种产犊记录,按不同配种年龄、胎次与配种月份所产犊的性别进行统计分析。结果表明:配种年龄对奶牛产犊性别无显著影响(p>0.05);胎次与奶牛产犊性别的关系表现为第三胎所产公犊显著多于母犊(p<0.05),其它各胎次差异均不显著(p>0.05);配种月份对奶牛产犊性别的影响表现为3-5月配种所产犊牛有母犊多于公犊趋势,但差异不显著(p>0.05),6月-9月配种所产犊牛公犊显著多于母犊(p<0.05),其余各月份差异均不显著(p>0.05)。     

KM小鼠的繁殖性能及季节对其影响的观察

对KM小鼠的繁殖性能按月份和胎次进行了统计·结果表明:KM小鼠平均窝产仔数为12.01(n=7005),胎间隔为28.11d(n=6613).窝产仔数随胎次的增加而增多,到第5胎时最多,以后则减少;胎间隔则随胎次的增加而显著地下降.两者皆明显地受季节(温度)的影响,窝产仔数与各月份平均温度成负相关r=-0.798(P<0.01),胎间隔则与其成正相关r=0.915(P<0.01).KM小鼠繁殖的适宜环境温度为22～25℃.     

Twinning rate in buffaloes: A case report

The information of twin pregnancy frequencies in buffaloes is scarce in the literature. Evidence even indicates that twin pregnancies are not carried to term, but it does not seem to be the case. In this case report, the event of twin pregnancy in buffaloes is reported as well as its frequency. Twin birth is the presence of two or more embryos in a single gestation. Multiple births are uncommon in buffaloes since the species is uniparous. We studied a population of Murrah buffaloes in which slightly more than 13,000 births were observed. In this study, the frequency of occurrence of twin births in Murrah buffaloes was 0.14%. This low incidence impaired the estimation of genetic parameters. Twins can have advantages and disadvantages depending on the production system, which are discussed in this case report.