应用智能监控系统改善大型牧场奶牛繁殖性能的探讨

本试验旨在探讨应用智能监控系统对荷斯坦泌乳牛发情揭发率和受胎率的改善情况.试验选用澳亚集团东营神州澳亚四场的2 237头泌乳天数为40～200d的各胎次荷斯坦泌乳牛,随机分为2组,未佩带项圈的806头为对照组,另一组佩带有项圈的1 431头为试验组.对照组依靠尾根涂蜡笔进行发情揭发,试验组依靠智能监控系统进行发情揭发,...     

氟孕酮在提高奶牛受胎率上的应用

[目的]为了解决奶牛的繁殖障碍,特别是高产奶牛产后不发情或屡配不孕的问题。[方法]介绍以牛欢氟孕酮阴道海绵栓为核心组合的“二次发情配种法”,综述氟孕酮在提高奶牛受孕率上的研究与应用进展。[结果]结果表明:奶牛第一情期受胎率达到65%左右,其余牛经1个情期后自然发情配种,2次总发情率95%,受胎率90%,效果明显。[结论]该技术值得推广,解决了奶牛的繁殖障碍问题,促进了奶牛业的发展。     

家兔发情状态与受胎率和产仔数关系的研究

本文研究了家兔的发情状态与配种后的受胎率，以及产仔数之间的关系。以家兔阴粘膜颜色作为表观指标，将家兔的发情分为５个状态，其相应的阴粘膜颜色分别为：苍白、粉色、红色、大红、黑紫。经促排２号诱发排卵后，人工授精，相应状态下的受胎率为：２９．５％、４２．９％、５６．８％、５３．８％、２５．０％；相应状态下的平均产仔数分别为：５．５４、６．６９、６．６２、７．２１、５．５２。用促排３号处理后，相应状态下的受胎率为：９．０％、４３．２％、５３．２％、７０．０％、２１．７％。结果表明：无论是用促排２号，还是用促排３号处理，当阴粘膜颜色为苍白和黑紫时的受胎率或产仔数，都显著地低于或少于阴粘膜颜色为粉色、红色、大红时的受胎率（Ｐ＜０．０１）或产仔数（Ｐ＜０．０５）。说明，家兔的发情状态与配种后的受胎率和产仔数有密切的相关     

低效林评判与改造途径的探讨

低效林属人为因素的直接作用或诱导自然因素的作用所致，影响了森林功能与效益的正常发挥，是造成林业整体效益水平低下的主要原因之一。本文在讨论低效林概念与评判标准的基础上，分析了低效林的现状、影响、改造途径与方法以及面临的主要问题。     

使用PMSG等激素提高四川黄牛繁殖效率研究再报

在初报基础上改进用药方法、扩大试验规模到２４头。发情率９５．８％，总受胎率７０．８％，得一胎孪生牛；校正后的产Ｄｕ间隔以对照组有显著缩短。该处理方法在缩短空怀期、治疗屡配不孕等方面表现了良好作用。重点讨论了该方法的适应范围、对动物选择的要求，以及处理后再发情时间与受孕效果的关系。     

净月潭国家森林公园生态旅游开发构想

概述了净月潭国家森林公园旅游资源情况．提出了其开展生态旅游的必要性及必须遵循的原则、包括生态学理论指导原则、全面规划原则、旅游资源保护优先原则、景观协调性原则和区内旅游、区外服务原则。针对净月潭国家森林公园的开发建设现状提出了其开展生态旅游应进行的旅游环境建设重点．在此基础上根据旅游资源特征对生态旅游项目提出了建议。     

辽宁省生态环境需水量研究初步探讨

随着经济、社会和生态环境可持续发展战略的实施，生态环境需水已成为水资源优化配置的重要内容之一，作为辽宁省这个东北老工业基地的代表来说，水资源的优化配置更是当务之急。本研究在总结分析前人研究工作的基础之上，对生态环境需水的概念、国内外研究现状、计算方法等基础问题进行了初步研究和探讨，以期为辽宁省水资源综合规划提供技术参考。     

季节·胎次与年单产水平对荷斯坦牛受胎率的影响

[目的]为提高芜湖地区荷斯坦牛的受胎率提供参考依据.[方法]基于奶牛场多年生产记录,研究不同季节、胎次与年单产水平对芜湖地区中国荷斯坦奶牛受胎率的影响.[结果]气温对奶牛受胎率有显著影响(P＜0.05),而湿度对奶牛受胎率的影响不显著(P＞0.05).胎次和年单产水平对奶牛受胎率有极显著影响(P＜0.01).夏季由于热应激,奶牛的受胎率会明显低于其他季节,秋季的奶牛受胎率最高.胎次越高的奶牛受胎率越低,青年奶牛的受胎率最高;年单产水平越高,奶牛的受胎率越低.[结论]不同季节、胎次与年单产水平对奶牛的受胎率都有影响.     

Effect of environmental factors on fertility of Holstein–Friesian cattle in Japan

We investigated the environmental factors in Japan, including meteorological conditions, on the fertility of a European cattle breed, Holstein–Friesian, by examining conception rates in different regions. First artificial insemination and associated conception details were recorded for 69,952 Holstein female cattle. In general, meteorological conditions vary considerably according to latitude in Japanese islands. Conception rates were higher in the Northern (above 37°N) than the Southern (below 37°N) region (61.3% vs. 53.3%). All the factors analyzed in the statistical model, including insemination year, region, month, AI technician, service sire and interaction between region and month, had significant effects on the conception rate. In the Southern region, conception rates were lower in the summer months (average temperature, 27.8 °C, and maximum temperature, 32.3 °C). However, this seasonal decline was not observed in the Northern region (average temperature, 23.7 °C, and maximum temperature, 28.4 °C). Regression analysis of conception rate in relation to temperature showed highly significant negative regression coefficients (− 0.66 to − 0.63% per °C; p < 0.001) in the Southern region, but non-significant coefficients in the Northern region. Humidity had a minimal effect on conception rate in both regions. Our data collectively suggest that 37°N latitude is a threshold that affects Holstein–Friesian conception rates in Japan.     

Follicular dynamics during the pre-ovulatory and subsequent first follicular wave stages affect the pregnancy outcome in Japanese Black cows

The diameters of the pre-ovulatory follicles (PF) and the largest follicle during the subsequent first follicular wave (W1LF), and plasma estradiol-17β (E₂) concentrations were monitored on Days 0, 1, 3, 5, and 7 (ovulation = Day 1). Pregnancy was diagnosed on Day 30. Cows were classified into two groups according to the location of the dominant follicle ipsilateral (IG) or contralateral (CG) to the corpus luteum on Day 7. From Days 3 to 7, some follicles that had been determined as the subordinate in the previous examination exceeded the W1LF located in the opposite ovary in terms of the diameter. These were defined as switching (SW), whereas others were defined as non-switching (NSW). The diameter of PF was significantly smaller in pregnant (P) animals than in non-pregnant (NP) animals. The plasma E₂ concentration on Day 0 was significantly higher in P animals than in NP animals and tended to be higher in NSW than in SW. In addition, plasma E₂ concentrations around Days 3 to 7 tended to be higher in P animals of NSW than in NP animals of SW. The conception rates did not differ between IG and CG but were significantly higher in NSW than in SW. In the IG group, the conception rate tended to be higher in NSW than in SW.