超低温冷冻对奶牛胚胎超微结构的影响

奶牛冷冻胚胎移植成活率较鲜胚移植明显低.为明确低温冷冻造成胚胎损伤的机理、为冷冻保存方法的进一步改进提供理论依据,利用透射电子显微镜观察了奶牛胚胎常规冷冻和玻璃化冷冻前后的超微结构变化.结果表明,奶牛鲜胚细胞分为两种类型:一种位于内细胞团(ICM)外层,胞质电子致密度低而着色浅,并含有大量的线粒体和内质网;另一种位于ICM中心区域,着色较深,溶酶体的数量多,其余细胞较较少.常规冷冻后,透明带和卵周隙明显变宽,细胞间接触变得松散.囊胚中含有退化的胞核和凋亡小体,内质网变大、变粗,脂滴明显增多.玻璃化冷冻后,ICM细胞的结构发生破坏,部分细胞发生崩解,细胞碎片大量分布于细胞间隙和卵周隙中,并可见大量的脂滴,凋亡细胞和凋亡小体增多.冷冻过程对早期胚胎细胞器的损伤可能是移植后成活率下降的主要原因.     

奶牛新鲜和冷冻胚胎分割移植试验

用简单方法,分割7～8日龄新鲜牛胚胎(1分为2),裸半胚成对移植给66头受体,90天妊检,移植妊娠率为56.1％(37/66)。除6头流产和尚有5头待产外,已有26头受体产犊35头,其中有9对同卵双胎,双胎率为34.6％(9/26),半胚产犊率为29.2％(35/120)。对影响成对半胚移植妊娠率和半胚产犊率的诸多因素如胚胎质量,胚胎在体外停留时间、胚胎发育阶段、受体牛品种、黄体状况等进行了较系统的研究。同时对冷冻胚胎进行了分割试验,移植妊娠率为45.5％(5/11),已产3头犊牛。对快速冷冻和常规冷冻胚胎分割后的移植妊娠率进行了比较,分别为25.0％(1/4)和57.4％(4/7)。     

奶牛冷冻胚胎分割移植效果探讨

分割加拿大奶牛冷冻胚胎 ,借荷斯坦牛受体移植。共分割冷冻胚胎 1 5枚 ,分割为裸半胚 30个 ,分割成功率 1 0 0 %。移植受体 2 7头 (其中移植一对半胚的受体 3头 ) ,移植妊娠 1 4头 ,受体移植妊娠率51 .85% ,产犊 1 4头 ,半胚产犊率为 4 6 .6 7% ,按未分割的整胚计算 ,产犊率达到 93.34 % ,比整胚移植产犊率还提高 1 8.34个百分点。移植半胚生产 1头犊牛需胚胎 1 .0 7枚 ,比整胚减少 0 .2 6枚 ,降低成本1 51 0 .6 0元。说明胚胎分割是降低成本 ,扩大卵源 ,增加良种牛数量的有效方法。     

茶多酚调控机制及其对奶牛乳房炎的干预作用

茶多酚（tea polyphenols,TP）是茶叶中的多酚类物质,属于稠环芳香烃,在抗氧化、抗肿瘤、抑菌、抗病毒、抗辐射、抗心血管疾病等方面均发挥生物学作用。介绍了茶多酚的组成成分和理化性质,综述了茶多酚发挥抗炎作用主要涉及的信号通路及其在奶牛乳腺上皮细胞（bovine mammary epithelial cells,BMEC）炎性反应中的作用研究进展,以期为探究茶多酚在预防和治疗奶牛乳房炎中的应用价值提供参考。     

氧化应激对围产期奶牛乳房炎的影响及其调控机制

奶牛乳房炎是一种常见的奶牛代谢性疾病,发病率呈逐年上升趋势。目前已证实,氧化应激成为困扰围产期奶牛生产中的一大问题,在诱发奶牛乳腺细胞破坏或功能障碍方面发挥关键作用。主要是由于动物机体抗氧化功能降低导致自由基产生和清除失衡所致,且持续的氧化应激可通过产生大量的氧自由基来攻击细胞,干扰其正常代谢、增殖和分化,并可能进一步诱发机体自身免疫反应,形成瀑布式效应,造成乳腺细胞产生不可逆性损伤。且核因子E2相关因子2-抗氧化反应元件(Nrf2-ARE)信号通路是细胞对抗外源性刺激和氧化损伤的主要机制。本文主要综述了氧化应激、氧化应激与围产期奶牛乳房炎、机体氧化应激的自我调控机制,对于确保奶牛在围产期内能够维持机体健康、发挥正常的泌乳功能和提高生产性能具有重要意义。     

受体奶牛不同同期发情处理方法对胚胎移植效果的影响研究

本试验选择产后60天以上、空怀、无疾病、体况适宜、年龄2～10岁的182头黑白花奶牛,随机分成第1、第2两组同期发情,发情7天后胚胎移植。第1组为CUEMATETM孕酮栓 PG(n=120),第2组为PG一步法。试验结果表明,第1组牛的黄体不合格率显著高于第2组(P<0.05);产犊率低于第2组,但差异不显著(P>0.05)。从经济实用角度看,本试验初步显示:PG法比CUE-MATETM孕酮栓 PG法好,成本低、操作方便、产犊率较高。     

奶牛热应激的发生机制及其预防研究进展

为预防热应激对奶牛生产的影响,文章对奶牛热应激的发生机理、危害及其预防措施进行了综述。     

奶牛健康监测与评价

牛奶的安全问题与奶牛的健康息息相关,只有健康的奶牛才能生产出健康的牛奶.牛群健康管理需要随时观察、定时检测,做到“未病先防”.因此,建立奶牛健康预警系统尤其重要,通过对单个敏感指标（乳体细胞数、牛乳pH、电导率、直肠温度、产奶量等）的变化和行为学观察及体况评分、运动评分、健康指数可以及时发现亚健康牛,减少疾病造成的损失,确保原料奶的品质安全.     

牛胚胎玻璃化冷冻保存研究初报

传统的胚胎冷冻方法需诱发结晶,按一定速率降温,不仅程序复杂费时间（需几小时）,而且还得使用价值昂贵的胚胎冷冻仪。为此,１９８５年Ｒａｌｌ等人首先发明了玻璃化冷冻法［１］,不使用冷冻仪,将冷冻时间缩短（约为３０ｍｉｎ）。但他们选用的是以大约７ｍｏｌ／Ｌ二甲基亚砜为主的抗冻剂,因其化学毒性大,对胚胎的存活带来一定影响［２,３］。１９８６年Ｓｃｈｅｆｆｅｎ等人,利用丙三醇及丙二醇为抗冻保护剂,因化学毒性仍较大,冷冻保存后的胚胎成活率仍不稳定［４］。针对化学毒性问题,１９９０年Ｋａｓａｉ等人利用化学毒性…     

The Effect of Pasture Nitrate Concentration and Concentrate Intake after Turnout on Embryo Growth and Viability in the Lactating Dairy Cow

This study investigated the effects on embryo growth and survival rate of feeding heavily‐fertilised spring grass, containing high levels of quickly‐degradable nitrogen, to pregnant cows. Forty‐eight lactating Holstein cows between 2 and 8 weeks pregnant were turned‐out, after a one‐week transition period onto high‐ or low‐nitrate pasture and fed a high‐ or low‐concentrate supplement. Cows grazing the High nitrate pasture had significantly higher milk and plasma urea concentrations than cows grazing the Control pasture, while cows which were fed less concentrate had a notably higher plasma ammonia. However, there was no evidence that an increased quickly‐degradable nitrogen (QDN) intake from pasture affected embryo survival or growth from 20 days onwards. This suggests that the impact of turnout on fertility mainly affects ovulation, fertilisation and/or the early embryo.     

奶牛流通领域的检疫措施

近些年来 ,齐齐哈尔地区的奶牛饲养业得到长足的发展 ,其中城区奶牛饲养量已超过４．５万余头 ,每年都有上千头奶牛销往省内外。为深入地贯彻“预防为主”的方针 ,更好地发挥检疫把关的职责作用 ,我站对即将进入流通领域的奶牛 ,开展了健康检查和检疫工作。凡符合健康标准并检疫合格的奶牛 ,均按规定出具全国统一使用的检疫合格证明。既保证了对外提供健康牛源 ,又客观地达到了督促淘杀慢性病畜的目的 ,为奶牛饲养业的发展提供了保障性措施。１材料和方法１．１牛型提纯结核菌素、布鲁氏菌虎红平板凝集试验抗原及其阴性和阳性血清 ,均为黑龙…     

Sequential Hormonal Changes in the Postpartum Dairy Cow

Peripheral plasma levels of 15-keto-13,14-dihydro-PGF_2α, progesterone, Cortisol, LH and prolactin were studied in 6 primiparous postpartum dairy cows. The cows were followed by hormone measurements and clinical examinations from parturition until pregnancy was established. Blood was collected 3 times per day. The cervix, uterus and ovaries were examined by rectal palpation at 6–10 days intervals. The cows were observed for signs of oestrus twice daily and were additionally teased with a bull to provoke standing heat.Four cows had a normal parturition and dropped their fetal membranes shortly afterwards. (NR group). The remaining 2 retained their fetal membranes for more than 24 h following parturition (RFM group). One out of 6 cows showed standing oestrus at the first ovulation, 4 animals were in oestrus at the second ovulation and all cows showed signs of oestrus at the third ovulation. Although the length of the first luteal phase varied from 9 to 22 days a corpus luteum was in all cases palpated. The secretion of progesterone during the first luteal phase was terminated by a PGF_2α release.A significant difference in 15-keto-13,14-dihydro-PGF_2α levels between the 2 groups was found on days 0–4 (2.39 vs 6.87 nmol/1 at Ρ < 0.06). Postpartum prostaglandin F_2α release as reflected by the level of 15-keto-13,14-dihydro-PGF_2α lasted shorter in the NR group than in the RFM group (15–17 vs 21 days). Significant positive correlations between 15-keto-13,14-dihydro-PGF_2α and Cortisol as well as between prolactin and Cortisol during the first 24 days postpartum were noted only in cows having normal parturition. The most pronounced daily prolactin variations occurred during the second luteal phase (NR group), when a significant difference between the times 8.00, 12.00 and 15.00 was recorded (14.7, 31.5 and 19.7 μg/l, respectively). Moreover, a partial negative correlation between log value of prolactin and arithmetical value of LH was found in these cows only during the first luteal phase after parturition.     

奶牛酮病的发病机理研究现状及防治策略

本文主要就奶牛酮病的发病原因、发病机理的研究现状及其防治作一简要的综述,旨在对奶牛酮病的研究提供理论依据。     

Effect of Different Doses of Prostaglandin on the Area of Corpus Luteum, the Largest Follicle and Progesterone Concentration in the Dairy Cow

Lactating dairy cows with a mature corpus luteum (CL) (diameter of ≥17 mm determined by ultrasonography) and having a follicle with a diameter of 10 mm (n = 49) were randomly assigned to three groups. The first group was treated with a single dose of exogenous prostaglandin (25 mg), while the second group was treated with 35 mg on day 0, and the third group served as control in order to evaluate the effect of rectal manipulation on the CL during ultrasonographic examination. Blood samples were collected daily for analysing progesterone (P4) concentrations. In group 1 the incidence of oestrus and artificial insemination (AI) in 10 days after treatment was 95% (19 of 20). The conception rate was 31.6%, and the average time to oestrus after treatment was 3.7 day. In group 2 the incidence of oestrus and A.I. was 84.2% (16/19). The conception rate was 31.2%, and the average time to oestrus after treatment was 2.8 day. In the untreated group only two cows (2/10) exhibited oestrus during the examined period and none of them became pregnant. There were no significant differences between the two treated groups in terms of reduction in the area of CL and P4 concentrations and of an increase in the area of the dominant follicles. At the same time, the decrease in the percentage changes relative to the area of CL and to the concentrations of P4 were statistically significant in both treated groups.     

一例奶牛皱胃溃疡伴低血钾综合征的临床治疗

2005年12月郑州牧业工程高等专科学校附属兽医院接诊了1例皱胃溃疡伴低血钾综合征的奶牛，该牛同时患有低血钙、酮病等。病情发展中患牛在血钾含量为2.28 mmol/L时四肢无力，卧地不起，通过补钾及综合治疗血钾升至3.45 mmol/L时又能自主站立，对皱胃溃疡采取消炎、抑制胃酸分泌、收敛止血等方法进行治疗。     

乳酸环丙沙星治疗奶牛急性乳房炎的临床试验

为研究乳酸环丙沙星治疗奶牛乳房炎的效果及其与青链霉素、公英散治疗乳房炎的疗效比较,应用乳酸环丙沙星,以加味公英散、青链霉素为对照,对127例奶牛急性乳房炎乳区进行了临床治疗试验.乳酸环丙沙星（44例）、加味公英散（41例）和青链霉素（42例）治疗的总有效率分别为90.9%、70.7%和73.8%,总痊愈率各为77.3%、53.7%和54.8%.经统计学检验,乳酸环丙沙星治疗组和青链霉素治疗组与加味公英散治疗组之间差异显著.青链霉素治疗组与公英散治疗组之间无显著差异.三种治疗疗程接近,经统计学检验,各组之间无显著差异.临床观察表明,乳酸环丙沙星能很快消退乳房炎症状,且其病原菌转阴率高.乳酸环丙沙星临床疗效比青链霉素和加味公英散好,刺激性小,疗效稳定,值得推广.     

奶牛骨质疏松症防治分析

奶牛骨质疏松症是成年牛骨骼生长完成后，由于钙磷代谢紊乱而发生的一种慢性全身性代谢病。其病理变化特点以骨质脱钙、骨质疏松、骨骼变形为主要特征。     

奶牛酮病的诊断与治疗

据统计，酮病的发病率有逐年升高的趋势。酮病可降低奶牛对其他疾病的抵抗力，从而引起多种疾病的发生，增加治疗费用，严重影响奶牛养殖业的有效发展。鉴于此，笔者根据多年的临床经验．对此进行简单的探讨，以期对广大养殖户和同行有所帮助。