同期发情及腹腔内窥镜输精技术在肉羊产业化中的推广应用

同期发情及腹腔内窥镜输精技术在肉羊产业中的广泛应用,对于改变肉羊产业的生产方式及经济结构,达到一年两产或两年三产的目的具有重要意义。在繁殖及非繁殖季节对内蒙古地区当地杂交羊进行了同期发情及腹腔内窥镜输精处理。结果表明,繁殖季节与非繁殖季节的发情率均在93%以上,差异不显著;对部分具有小尾寒羊血统的杂交羊同期发情处理后的第6天进行手术检查黄体,其排卵率分别为2.45个/只和1.68个/只。在受胎率方面,腹腔内窥镜输精的受胎率显著高于常规法人工授精的受胎率。     

Comparison of Metabolic Energy Content of Organic Cereal Grains for Chickens and Turkeys

Although there is an extensive database on the nutrient content of conventionally produced feedstuffs, there is very little published research on the nutrient content of feedstuffs that are organically grown. Industrial and organic crop production differ in both crop and soil management. There are data to suggest that these differences may result in differences in the nutrient content of organic grown feedstuffs. The purpose of this study was to determine the ME content of organically grown amaranth, buckwheat, white corn, yellow corn, and wheat samples obtained from the University of Minnesota's organic research farm. Both chickens and turkeys were used in the assays to compare the ME content for these 2 species. The TME_n content, on an as-fed basis, of amaranth, buckwheat, yellow corn, white corn, and wheat for chickens were found to be 3,146, 3,072, 3,603, 3,324, and 3,592 kcal/kg, respectively. The TME_n content of the same samples, on an as-fed basis, determined with turkeys were found to be 2,748, 2,227, 2,810, 2,757, and 2,959 kcal/kg, respectively. True ME content of the organically grown feed ingredients was found to be greater when chickens were used in the bioassay as compared with turkeys and differed significantly from published values for the same cereals grown using conventional means.     

病毒细胞受体研究技术及其应用现状

病毒感染宿主细胞的过程实质是病毒受体与配体之间的相互作用。病毒受体和配体的研究是明确病毒致病机理的关键,因此关于病毒细胞受体的研究一直是近年来病毒学研究的重点领域。病毒受体的鉴定可通过多种生物技术手段进行,如酵母双杂交法、病毒覆盖蛋白结合技术等。文章对当前的病毒细胞受体研究技术及其应用现状进行了综述,以期为今后的相关研究提供参考。     

Fecal D- and L-lactate, succinate and volatile fatty acid levels, and relationships with fecal acidity and diarrhea in neonatal calves

To clarify the significance of fecal organic anions in neonatal diarrhea, a total of 252 fecal samples (91 diarrheic, 161 normal) were collected from 136 dairy calves (including three crossbreds) less than 4 weeks old. Fecal pH, D‐ and L‐lactate, succinate and volatile fatty acid (VFA) were analyzed. In normal feces, lactate was highest and VFA was lowest at week 1 of age, and lactate progressively decreased and VFA progressively increased with advancing age. In diarrheic samples, although higher pH and lower lactate levels were confirmed at week 1, samples at weeks 3–4 showed lower pH and VFA accompanied by higher lactate of D and L‐isomers. In diarrhea, fecal butyrate was significantly lower at all stages, but succinate levels did not differ significantly. The proportion of lactate to organic anions (sum of lactate, succinate and VFA) in diarrheic feces was lower at week 1, and higher in weeks 2–4, while that of VFA to organic anions showed the opposite pattern. Strong relationships were observed between fecal pH and lactate, and VFA proportions in organic anions, though the relationship was weak in diarrhea. Most of the elevated lactate was observed in fecal samples with lower VFA. However, succinate had no relationship with VFA or lactate levels.     

苗期施用钠复合肥增强梭梭抗逆性的初步研究

利用盆栽育苗的方法,施用钠复合肥后培育梭梭植株,使其正常生长70 d后干旱20 d进行沙地移栽试验,3个月后生长期结束测定其形态指标、生物量以及Na⁺和K⁺含量,初步探讨了钠复合肥在培育强抗旱梭梭植株方面所起的作用。与对照(不施任何肥料)和施用(NH₄)₂HPO₄(与钠复合肥含等量的N、P)的处理相比,施用钠复合肥的梭梭株高分别增加了26%和12%;分枝数增加了22%和14%;主茎直径分别增加了48%和23%、主根直径分别增加了37%和24%;冠幅分别增加了57%和28%;根冠比均增加了18%;鲜重分别增加了130%和74%、干重分别增加了154%和74%;地上部的Na⁺含量分别增加了45%和38%,根中的Na⁺含量分别增加了15%和12%;地上部中的K⁺含量差异不显著,根中K⁺含量分别降低了28%和31%。以上结果表明,钠复合肥的施用能有效地促进梭梭的生长并提高其抗旱能力。     

施用镁肥对桑叶产量和叶质的影响

试验表明在Ｋ／Ｍｇ相对较高的酸性土壤,施用镁肥可提高桑叶产量和改善桑叶品质,在生产上可以施用钙镁磷肥或喷施２％硫酸镁溶液。     

日粮补充苹果渣或有机矿对鹅生产性能、蛋品质及繁殖性能的影响

本研究旨在评估日粮单独添加苹果渣或补充苹果渣和有机微量元素对鹅生产、繁殖性能及蛋品质的影响.试验将产蛋期的360只鹅随机分为3组,每组120只(30只/重复),对照组饲喂基础日粮,处理组分别饲喂苹果渣日粮和苹果渣+有机微量元素日粮,试验持续14周.结果:苹果渣补充或不补充有机矿较对照组显著提高了孵化率和仔鹅存活率(P<...     

近交在畜牧业中的应用及防止衰退的措施

近交是指5代以内双方具有共同祖先的公母畜交配,在培育品种或品系过程中,常常采用近交以固定某些优良性状,或藉以增加某个优良种畜的血统。近交虽是育种工作中的一种有力措施,但使用不当就会出现近交衰退现象。因此,不能将其作为生产中的经常性措施,一般只在育种场采用,在商品场不宜采用。