Bisection of bovine morulae and blastocysts from superovulated Danish dairy cows

Sixtyfour compacted morulae and blastocysts were bisected with a microscalpel. The majority of the demi-embryos (n = 122) were reinserted into separate zona pellucidae (ZP) before non-surgical transfer to 113 synchronized recipients, as singles (n = 98) (DE-S) or in pairs (n = 30) (DE-P). Thirty non-manipulated embryos (E) were transferred during the same period and served as controls. Pregnancies were diagnosed by rectal palpation 4-7 weeks after transfer. The pregnancy rates for DE-S, DE-P and E were 32%, 53% and 40%, respectively (P greater than 0.05). A substantial number of abortions were recorded between 50 and 250 days of pregnancy among the recipients with DE-S. The fetal survival rate for DE-S was reduced to 21% and significantly lower (p less than 0.05) than the survival rates of DE-P (43%) and E (40%). The quality of DE and the presence of ZP did not significantly influence the results. No conclusive reasons for the fetal loss could be found but different possibilities are discussed.     

依葡柠解冻液对种公牛精子寿命及完整顶体率的影响

采用复方依葡柠解冻液 (EDTA 葡萄糖 柠檬酸钠 ,试验组 )与常用的单方柠檬酸钠解冻液 (2 .9%柠檬酸钠 ,对照组 )对肉用种公牛颗粒冻精进行解冻对照试验。结果显示 ,解冻后精子的复苏率 ,试验组与对照组相差不大 (P >0 .0 5 ) ;常温 (18～ 2 0℃ )和低温 (5～ 7℃ )下再贮存 ,精子的存活时间和生存指数 ,试验组高于对照组 ,且差异显著 (P<0 .0 5 ) ;解冻后在 (38± 2 )℃水浴中孵育 3h检查精子的完整顶体率 ,试验组极显著高于对照组 (P<0 .0 1)。适用于水牛的良好解冻液依葡柠 ,用做牛 (肉用牛 )的冻精解冻得到了理想效果     

盐度对才女虫幼虫存活的影响

试验结果表明，采自盐度16水体中的才女虫（Polydora sp.)幼虫，其24h存活盐幅为40－3；采自盐度5水体中的才女虫幼虫，其24h存活盐幅为15－3。盐度16水体中的才女虫幼虫经过逐步驯化后，盐度生态幅增大，其24h安全存活盐幅为50－2。     

几种处理方法对四翅滨藜嫩枝扦插成活率影响的研究

采用不同的插穗长度、取穗部位及扦插基质等处理方法,进行了四翅滨藜嫩枝扦插育苗试验,以研究对其成活率的影响。结果表明:以插穗长度为8~10 cm,取中上部位的当年生嫩枝作插穗,育苗基质配比为大田土?泥炭?沙子=7?3?4的四翅滨藜嫩枝扦插育苗成活率较高。     

A comparison of two dose levels of antibiotics for intramammary treatment of clinical mastitis in cows

A clinical trial was conducted in Nordre Valdres, Norway, to examine the effect of a low-level vs. a high-level intramammary antibiotic treatment of clinical mastitis. It was also of interest to identify significant risk factors and to estimate the probability of no recovery for given defined levels of risk factors. Quarter milk samples from 166 cows with clinical mastitis were examined before and after treatment, at 3 weeks interval. The two treatment levels did not differ significantly with respect to recovery rate. The probability of no recovery could be estimated by using information on the severity of general clinical signs, lactation number, bacteriological findings, and quarter location.     

提高新疆杨扦插成活率途径的研究

新疆杨属于难生根的树种,在乌兰察布地区利用硬枝直接扦插成活率不足30%,严重制约着该树种的扩繁工作.经过多年试验表明,采取对插穗进行催芽处理等一系列育苗技术措施,可使新疆杨硬枝扦插成活率提高到80%～95%.     

不同保墒技术在石质山地人工造林中的应用研究

贵州省地处山区，喀斯特地貌类型分布广，其岩石裸露率高，土被不连续，土层浅薄，碳酸盐类岩石渗漏性强，土壤持水量低，临时性干旱不时出现，影响人工造林和植被恢复的进程和成败，并成为人工造林的困难地段。为提高该地区造林成活率，人们曾采用各种方法保墒，如覆盖地膜、沾泥浆、沾保水剂等，虽然成活率有所提高，却因成本太高而未能大面积推广。2年来笔者在石质山上进行了覆盖地膜、沾保水剂、盖山草压石、盖松针压石等不同保墒方法试验，并进行成本核算，结果表明因地制宜采用盖松针压石、盖山草压石保墒方法效果显著。现将结果报告如下：     

加强自主创新,全面提升我国木材工业整体竞争力

通过回顾近年来我国木材工业的发展成就，提出在全球经济一体化新形势下，我国木材工业应根据国家可持续发展战略的总体目标，加强自主创新，推进经济结构调整和经济增长方式转变，全面提升我国木材工业整体竞争力。     

不同处理因素对小尾寒羊精子存活时间的影响

用0．9％的生理盐水和VB12注射液稀释小尾寒羊的鲜精液后，分别放置在恒温箱（25℃），常温（21．3℃－26．4℃），冰箱（5℃－10℃）中保存，试验结果表明：用VB12注射液作为小尾寒羊鲜精液稀释液，在5℃－10℃冰箱中保存，可明显延长精子的有效存活时间。