浅谈海原县肉牛繁育现状及对策

本文对现阶段海原县肉牛繁育现状进行总结,即基础母牛饲养量逐年增加,品种趋向良种化;养殖模式由单一散养户逐渐转向规模场(户);养殖技术由原始粗放逐渐转向科学精细化;地方政策支持力度加大,配套体系逐渐健全。并分析了几个制约肉牛良繁的问题：即中大规模养牛场出现本交现象;饲养管理不精准导致“一年一胎”难实现;犊牛成活率低等问题。针对存在的问题从提高冷配繁育技术、母牛规范化饲养管理、提高犊牛成活等方面提出了相应的解决办法。     

我国辣椒育种研究进展(上)

概述了我国辣椒种质资源、育种目标及育种方法等方面的研究进展，并对今后的辣椒育种工作提出了建议。     

Classical swine fever in The Netherlands 1997-1998: a description of organisation and measures to eradicate the disease

The central and regional organisation of the campaign to eradicate the CSF epidemic in the Netherlands in 1997/1998 is described. The main instruments used in the campaign were based on stamping-out and movement restrictions specified by the European Union. Additional instruments were used for the first time, namely, pre-emptive culling of contact and neighbouring farms, compartmentalisation of transport, monthly serological screening in established surveillance areas and supervised repopulation of all farms in the former surveillance zone. Two other measures, the killing of very young piglets and a breeding ban were introduced to reduce production in established surveillance zones. Several factors complicated the eradication campaign, for instance, the late detection of the first infection; artificial insemination as a source of infection; the organisation of pig farming in the Netherlands, with its highly concentrated production and dependence on the transport of stock from one unit to another; insufficient rendering capacity; decreasing sensitivity of clinical inspection; and extremely high costs.     

家蚕春用品种研究现状及展望

家蚕新品种的选育和应用是蚕丝业科技进步的核心因素,春用蚕品种研究则是这个核心的重点。本文就国内外家蚕春用品种研究的历史、现状及发展方向进行阐述,希望对我国当前的蚕育种工作有所帮助。     

我国茸鹿育种研究进展及现代茸鹿育种探讨

综述了我国茸鹿育种自 1 958年始至今历经 42年 3个阶段 ,成绩显著 ,取得了令世界瞩目的成就     

Estimation of accuracies and expected genetic change from selection for selection indexes that use multiple‐trait predictions of breeding values

Procedures are described for estimating selection index accuracies for individual animals and expected genetic change from selection for the general case where indexes of EBVs predict an aggregate breeding objective of traits that may or may not have been measured. Index accuracies for the breeding objective are shown to take an important general form, being able to be expressed as the product of the accuracy of the index function of true breeding values and the accuracy with which that function predicts the breeding objective. When the accuracies of the individual EBVs of the index are known, prediction error variances (PEVs) and covariances (PECs) for the EBVs within animal are able to be well approximated, and index accuracies and expected genetic change from selection estimated with high accuracy. The procedures are suited to routine use in estimating index accuracies in genetic evaluation, and for providing important information, without additional modelling, on the directions in which a population will move under selection.     

Ultrasonography of the spleen in 50 healthy cows

This paper describes the ultrasonographic appearance, location and size of the spleen in 50 healthy commercial milk cows destined for slaughter. The intercostal spaces of the left thoracic wall were scanned with a 3.5 MHz linear transducer. In each intercostal space, the appearance of the splenic parenchyma, the dorsal and ventral margins and the distance between them, and the diameter of the splenic vessels were recorded. The spleen was seen in intercostal spaces 7-12. It was 2.0-5.0 cm thick, and tapered ventrally. The splenic capsule appeared as an echogenic line. The splenic parenchyma consisted of numerous small regularly spaced echoes, and vessels within the parenchyma appeared as anechoic round to oval or elongated images. The long axis was oblique, running caudodorsal to cranioventral. The distance from the dorsal margin of the spleen to the midline of the back was greatest in the 7th intercostal space (60.9+/-6.81) and smallest in the 12th intercostal space (12.7+/-2.85 cm). The extent of the spleen was greatest in the 8th intercostal space (24.9+/-10.77 cm) and smallest in the 12th intercostal space (9.5+/-5.38 cm). The mean diameter of the splenic vessels ranged from 0.66+/-0.28 to 0.90+/-0.65 cm, depending on the intercostal space scanned. Ultrasonography of the spleen in healthy cows provides information that can be used as a reference when examining cattle with suspected splenic disease.     

适合亚热带蚕区饲养的三眠蚕育种材料选择

为了培育适合亚热带蚕区生产高品位生丝的家蚕品种,根据家蚕眠性遗传机制,利用杂交育种及显性三眠纯合技术,将超细纤度三眠蚕品种与夏秋蚕品种杂交育成Z3等细纤度三眠蚕材料,再与多丝量春用蚕品种杂交,初步育成了Z3.C3等纤度为2.44 dtex、全龄经过短、体质强健、茧丝质优良的三眠蚕材料。采用选拔的三眠蚕材料初步组配的Z3×84Y2杂交组合的实验室饲养成绩为:全龄经过21 d,虫蛹率98.55%,全茧量1.75 g,茧层率22.47%,茧丝长1 354 m,解舒率88.15%,洁净95.3分,纤度2.6 dtex。