Ensiling characteristics of total mixed ration prepared with local feed resources in Mozambique and their effects on nutrition value and milk production in Jersey dairy cattle

To effectively utilize total mixed ration (TMR) prepared with locally available feed resources, we studied the nutritional value and milk production in Jersey dairy cattle fed a local general diet (LGD) and fermented TMR in Mozambique. Ten head of Jersey dairy cattle with 337 ± 19.8 kg body weight, aged 3–4 years in mid location were used in this study. The LGD diet was designed following the general feeding method of local smallholding farms; it contained native grass, Napier grass, wheat bran, and mineral–vitamin mix. Fermented TMR was prepared using Napier grass, corn bran, wheat bran, formula feed, and mineral–vitamin mix. Fermented TMR was preserved as good quality, with a relatively low pH and high lactic acid content. Compared to LGD, fermented TMR significantly improved the dry matter intake and digestibility in dairy cattle. Milk yield was significantly higher in dairy cattle fed with TMR than in those fed with LGD, by 3.75 L/d; milk quality was not significantly different between treatments. The results confirmed that LGD had a low dry matter intake and milk yield, and fermented TMR prepared with local feed resources can attain good quality and improve milk yield in dairy cattle in Mozambique.     

2018年中国部分地区猪瘟病毒2.1d亚型新流行株的基因组特征分析

为了解中国猪瘟病毒（classical swine fever virus,CSFV）的分子流行病学及遗传变异情况,本研究应用RT-PCR方法对2018年采集自河南、河北、山东、黑龙江和辽宁5个省份的350份疑似CSFV感染的病料进行E2和NS5B基因扩增,并对PCR产物进行测序和序列分析。结果显示,350份样品中21份为CSFV阳性,共获得14株CSFV的E2基因序列和7株CSFV的部分NS5B基因序列。E2全基因、NS5B部分基因序列分析表明,21份阳性样品均属于近年来在中国流行的CSFV 2.1d亚型,且新发现的2.1d亚型CSFV与中国较早2.1d亚型CSFV毒株间同源性差异不大,新发现的2.1d亚型CSFV分离株在E2基因的6个氨基酸（R³¹、S³⁴、W¹⁸²、K²⁰⁵、K³⁰³、A³³¹）上具有相同的分子特征,E2蛋白中15个位点上的半胱氨酸均未发生变异。韩国2.1d亚型CSFV在E2蛋白上具有3个独特的氨基酸（N⁹⁷、K¹⁵⁹、R²⁰⁵）特征,并且发现了韩国毒株YC11WB可能作为2.1b和2.1d亚型CSFV过渡毒株的证据,流行于中国和韩国的2.1d亚型CSFV可能分别来自于本国早期2.1b亚型CSFV的衍化。本研究证实,2018年中国及周边国家CSFV较为活跃,且流行毒株依然以2.1d亚型为主,为中国科学防控CSFV提供了依据。     

The Standardization of an Apparatus for the Mixing of Soil Samples for Nematode Extractions

Quantitative determination of nematode populations in soils frequently necessitates the mixing of representative soil samples to form a homogeneous, compound sample from which the nematodes are extracted. A mixing apparatus was developed and standardized with the aid of a spectrophotometric technique by which the dispersion of a dye through the soil during mixing could be determined. It was found that the mixer is most suitable for use on sandy loam soils. Optimal mixing is obtained at a speed of 15 rpm for 2 minutes. Under these conditions mechanical damage to nematodes during mixing is minimal.     

9个野生早熟禾对低温胁迫的生理响应及苗期抗寒性评价

以甘肃省境内采集的9个野生早熟禾（Poa）为试验材料,设5,0,-5,-10℃共4个温度处理,探讨其对低温胁迫的生理响应和抗寒性,为抗寒早熟禾种质材料筛选和新品种选育提供依据。结果表明：随着温度下降,各材料的叶片相对膜透性逐渐增大,游离脯氨酸（Pro）、可溶性糖（SS）、可溶性蛋白（SP）、丙二醛（MDA）含量逐渐增加,超氧化物歧化酶（SOD）和过氧化物酶（POD）活性逐渐增强。运用隶属函数法综合评价9个材料苗期抗寒性发现,一年生早熟禾（P. annua）抗寒性最强,小药早熟禾（P. micrandra）、草地早熟禾（天祝）（P. pratensis）和草地早熟禾（甘南）抗寒性中等;硬质早熟禾（P. sphondylodes）、波伐早熟禾（P. poophagorum）、草地早熟禾（肃南）、草地早熟禾 （渭源）、草地早熟禾（兴隆山）抗寒性弱。相关性分析表明,SP含量与抗寒综合评价值极显著正相关（P<0.01）,POD活性与抗寒综合评价值显著正相关 （P<0.05）,Pro含量、SS含量、SOD活性、海拔与抗寒综合评价值成正相关,相对膜透性、MDA含量和年均温与抗寒综合评价值成负相关。     

牛结核病的防控

牛结核病是由结核分枝杆菌引起的一种人畜共患慢性传染病.为有效控制和净化牛结核病,切实保障畜牧业生产安全、动物产品质量安全和公共卫生安全,必须坚持预防为主、因地制宜、分类指导、逐步净化的防控方针和策略,把养殖场(户)作为防控本病的主体,不断完善奶牛养殖场生物安全体系,严格落实监测净化、检疫监管、无害化处理、应急处置等综合...     

The relationship between carcass characteristics,plasma hormones and metabolites in young fattening bulls

Six Belgian Blue bulls (double-muscled type) and six Friesian bulls were offered a fattening diet for 34 weeks. Plasma samples were obtained once a week and also every 20 min over a 24 h period, 7 weeks before slaughter.No differences were observed between the breeds in plasma glucose, urea and free amino nitrogen concentrations, while creatinine was significantly higher in the Belgian Blue bulls. Tri-iodothyronin, tetra-iodothyronin, insulin-like growth factor 1, insulin and testosterone concentrations were higher in the Holstein group. In contrast, the Belgian Blue bulls appeared to produce more growth hormone. The slaughter weight, carcass weight, dressing percentage and proportion of lean meat were significantly higher in the Belgian Blue group. The characteristics of muscle mass (carcass weight, dressing percentage and proportion of lean meat) were positively correlated with creatinine and with the total peak area or peak amplitude of growth hormone. The insulin concentration was positively correlated with the proportion of adipose tissue in the carcass and negatively correlated with the proportion of muscle. There were no correlations between the carcass characteristics and insulin-like growth factor 1 or testosterone. No further information was provided when the ratios of the hormones were correlated with carcass characteristics.     

云南武定鸡肉品质分析

本试验对230日龄武定鸡不同性别和部位的肉质物理特性指标进行了测定分析。结果显示:①性别对230日龄武定鸡的肉质物理特性影响不大,仅在嫩度上母鸡优于公鸡,且差异显著(P<0.05);②部位对230日龄武定鸡肉质的物理特性有很明显的影响(P<0.05),胸肌的嫩度、贮藏损失、L值、b值均显著高于腿肌,而a值、pH值显著低于腿肌,只有系水率在胸部和腿部间没有显著差异(P>0.05);③阉割可以改善武定鸡肉质。     

一年生苜蓿种质资源形态变异及其形态特征

以22份一年生苜蓿为材料,对生育期和外部形状进行观测和统计分析,并对形态类型加以聚类分析。结果表明：（1）一年生苜蓿的茎为直立或匍匐,茎高在7．0～30．7cm,3出羽状复叶,种子为黄色、肾形。生育期在95—140d,从生育天数可分为早熟型和晚熟型;（2）一年生苜蓿种内变异很大,其中主茎长度和自然高度的变异系数最大,分别为43．0％和42．9％。其次是叶长和叶宽,变异系数分别为33．3％和30．0％。而第2主茎长度变异系数是27．6％,伸展长度变异系数22．1％;（3）对一年生苜蓿在干旱地区和高寒地区的生长状况的比较发现,一年生苜蓿更适应于干旱地区的生长;（4）一年生苜蓿的主茎长度越长,第2主茎长度越长,自然高度越高,伸展长度越长,叶长和叶宽也越长;（5）通过形态类型的聚类分析,可将一年生苜蓿分为3个类型,直立型,匍匐型和低矮型。     

禽坦布苏病毒研究进展

禽坦布苏病毒(avian Tembusu virus,ATMUV)是一种主要引起蛋鸭发病的新发病毒性传染病,该病毒自2010年4月以来给中国东南沿海地区的养鸭业造成了巨大经济损失,该病毒也可感染鸡、鹅等多种家禽发病.文章综述了ATMUV的病原学、流行病学、生物学特性、基因组学、诊断技术和疫苗研发的研究现状及前景,为进一步研究ATMUV提供参考.     

乳糖酶的固定化及其应用研究进展

乳糖酶在乳制品加工领域应用广泛,有很重要的研究利用价值.本文概述了乳糖酶的特性、固定化,重点分析了乳糖酶在乳品工业的应用研究进展,并展望了乳糖酶的发展前景.旨在为乳糖酶的固定化研究提供参考.