有机铬对奶牛的作用

奶牛在妊娠晚期、产奶早期、高温时期和运输过程中处于极度应激的状态下,生产性能、免疫力、繁殖性能均受到影响。近年来研究发现有机铬对缓解奶牛应激有显著的作用,本文将就此作一综述。     

Age‐related changes in semen quality characteristics and expectations of reproductive longevity in Duroc boars

Quadratic fitting was used to regress semen characteristics of 1441 samples consisting of 12‐month collection from 58 Duroc boars against animal age varied from 10 to 80 months. Data was divided into two groups of cool (14.0–22.7°C, RH 81.5%) and hot season (22.9–29.9°C, RH 86.6%), to test effects of age, season and their interactions. Results revealed that young boars of around 1 year old could endure the hot season. The endurance gradually diminished as animals grew. In the hot season animals exhibited peak performance at age around 33 month and it remained for 1 month, while cool‐season kept boars could last for 48 months from 16 months old onward. The reproductive longevity should be 51 month in a subtropical environment and it may extend to 70 month if heat stress can be avoided. The estimated total sperm contribution of a Duroc boar would be 1.8 times more when kept below 22°C than in a natural subtropical environment. It is concluded that to maintain Duroc boars as semen donor to at least 4 years of age is feasible in a subtropical environment and boar longevity could reach 6 years old if well kept in a temperate region.     

新引进国外牧草品种比较试验

为了适应我市奶业发展的需要，２０００年我们从国外新引进牧草品种４６个，第一批将９个冬季牧草品种在南平市大横现代农业科技园区引种园进行品种比较试验研究，现将这些品种试种、田间观察、考种测产及生产情况比较材料总结如下：１材料与方法１．１供试品种参试的牧草品种共有９个，即：白三叶（Trifoliumrepens）、紫花苜蓿（Medicagosativa）、多花甜皂角（Aeschynomenesp）、蒺藜草（Aesehynomenesp）、稷（Panicomcoloratum）、多花黑麦草（Loliumsp）、多年生黑麦草（Loliumperenne）、冬油菜（Kozepor）、春小黑麦（Narla）。…     

不同形态氮肥对紫花苜蓿生长、硝酸盐转运蛋白基因MtNRT1.3表达及氮吸收的影响

为了探讨豆科牧草对不同形态氮素的吸收,以紫花苜蓿（Medicago sativa L.）为试验材料,通过盆栽试验探究不同形态氮肥对紫花苜蓿生长、硝酸盐转运蛋白基因MtNRT1.3表达和氮吸收的影响。试验设有4个处理,分别为不施氮处理（对照组,Con）、施铵态氮（NH₄Cl—T1）、硝态氮（NaNO₃—T2）和混合氮（铵态氮、硝态氮1：1混合—T3）,各形态氮肥施加总量为按纯氮250 mg（每1 kg土）。试验结果表明,施氮处理提高了紫花苜蓿中的氮含量,施加各种氮肥均提高了紫花苜蓿根中MtNRT1.3基因的表达量,且该基因的表达量与土壤铵态氮和硝态氮呈正相关性（P<0.01）。相比于铵态氮肥,施加硝态氮肥不但可增加植株中硝态氮含量,而且能提高植株铵态氮含量;相比于单施硝态氮和铵态氮肥,混合氮肥对提高植株氮含量效果最好;施加硝态氮肥更有利于紫花苜蓿地上部分生物量的累积。因此,对紫花苜蓿施加氮肥应重视铵态氮和硝态氮的比例,增加硝态氮的比例更有利于紫花苜蓿的生长和对氮素的吸收。     

新发现的骆驼朊病毒病

骆驼朊病毒病是近来在北非地区发现的感染单峰驼的传染性海绵状脑病。发病骆驼年龄均在8岁以上,病程3~8个月,以行为异常、共济失调、反应过敏、不时倒地、站立困难为特征;在脑部特定区域出现海绵状空泡病变,通过免疫组化和免疫印迹方法能够检测到朊病毒。世界动物卫生组织（WOAH）暂未将该病判定为新发病。由于相关信息非常有限,本文仅对该病的起源、临床症状、病理变化、病原特点、WOAH观点、防控建议等进行简要介绍,以期引起我国动物疫病防控管理部门和相关从业人员的警惕。     

First report of <Emphasis Type="Italic">Neospora caninum</Emphasis> infection in cattle in Sudan

A cross-sectional survey was conducted in Sudan to determine sero-prevalence and risk factors associated with Neospora caninum infection in non-vaccinated dairy herds and to assess importance of the disease. Blood samples were collected from a total of 262 animals from 25 herds. Sera were tested for antibodies against N. caninum using ELISA test. The prevalence rates of N. caninum antibodies in cattle were high both at herd level (44%) and at individual animal level (10.7%). Herd level infection rates were similar in Khartoum State (43.7%) and at Gazira States (44.4%). The overall prevalence rates were higher (16.1%) in Gazira State than in Khartoum State (9%) but with no significant variation. The sero-prevalence at individual animal level was significantly higher (p < 0.05) in animals with history of abortion (12.8%) than in apparently healthy animal (11.3%), animal with history of infertility (8.1%), or neonatal death of calves (4.3%). In addition, significantly higher (P < 0.05) sero-prevalence was observed in samples collected during the rainy season (6.87%) than winter (3.05%) or summer (0.76%). However, no significant differences in sero-prevalence due to locality, animal breed, sex, and age were observed (p > 0.05). This preliminary study reveals for the first time the existence of natural N. caninum infection in Sudan. Also, the findings of the present study indicated that this disease is highly prevalent in two major areas of dairy production in the country, and this calls for control strategy to be implemented.     

新牧1号苜蓿两个抗逆相关基因启动子的克隆及分析

采用实时荧光定量PCR分析了新牧1号苜蓿（Medicago varia Xinmu 1）MvNHX1和MvDREB1基因在盐胁迫下的表达情况。此外,根据已获得的MvDREB1和MvNHX1基因序列设计特异引物,并以新牧1号苜蓿的基因组DNA为模板,克隆得到了这两个基因的启动子。利用生物信息学方法,分析这两个基因启动子的类型和结构,结果表明,MvNHX1和MvDREB1基因的启动子序列中均含有通用启动元件和上游调控元件,如CAAT框、TATA框、光响应元件、低温响应元件等,但部分响应元件的种类和数量不同。通过对两个基因启动子的克隆、分析及比较为进一步研究这两个基因的表达调控机制奠定了基础。     

北京市马属动物赛事监管制度的建立

通过对近年来重大马术活动的监管,结合《北京市动物防疫条例》的实施,北京市逐步形成马属动物展览演出比赛的“赛事报告、报检报验、档案记录、防疫条件审查、隔离观察、赛中监管、应急预备和宣传告知”八大监管制度,确保了北京市马属动物无疫安全。     

北京市猪肉市场供需及流通概况

本文分析了北京市食品消费结构、猪肉消费能力、生猪生产、猪肉供需缺口和流通,以及生猪屠宰布局规划等概况。其中对北京市猪肉消费、生产、流通等问题进行了详细分析。笔者认为随着经济的快速发展以及居民收入、消费水平地提高,北京市猪肉需求仍有较大增长空间,但由于北京城市发展规划及环保等方面原因,北京市猪肉生产仍将保持下滑,生猪生产将向周边转移,带动河北、辽宁等省生猪养殖业的发展。从而实现北京销区与周边产区产销流通,互利共赢,和谐发展。     

DHEA诱导小鼠PCOS模型过程中性激素的变化规律

【目的】鉴于在多囊卵巢综合征(polycystic ovary syndrome, PCOS)发病机理和治疗方式上的诸多争议,以及使用人类PCOS材料进行研究的局限性,本研究通过构建PCOS小鼠模型以探究在模型构建过程中性激素水平的变化规律。【方法】皮下注射脱氢表雄酮(dehydroepiandrosterone, DHEA)诱导昆明白雌鼠产生PCOS样临床症状,通过结晶紫染色查看小鼠性周期是否发生停滞;利用HE染色的方式确定卵巢发育状况;利用ELISA技术调查建模过程中血清睾酮和雌二醇浓度的变化规律。【结果】使用结晶紫对小鼠阴道上皮细胞染色可准确区分小鼠各个性周期阶段;使用6 mg/100 g DHEA持续诱导20 d后,昆明白小鼠性周期循环发生了一定的停滞,且在建模过程中体重变化与芝麻油溶剂的加入呈显著相关(P<0.05),与DHEA处理无关;DHEA连续处理后可见卵巢中巨大囊状卵泡出现,血清睾酮水平出现显著升高(P<0.05);自PCOS模型构建的第5天起,血清睾酮水平显著上升(P<0.05),且维持到建模结束;而血清雌二醇水平出现了阶段性变化,在第10、15天...