肉牛引进过程的操作技术规范

肉牛购进过程中存在的实际问题,可能给养牛企业和养牛户造成极大的损失。本文分别从购进牛只的选购目标、健康状况、饲养方式及疫病监测方面提出具体措施;新购牛在当地先需要一个隔离稳定观察期,并做好运输前各项准备工作;提出在运输环节中,对人员、车辆、消毒、草料及饮水准备,饲喂细节、抗应激处理、装车密度、运输过程中的注意事项等;运到后圈舍消毒、隔离观察、饲喂和饮水的过渡方法,强化免疫接种,等待牛群稳定后才可进入繁育或者育肥环节。     

不同海拔高度牛宰后牛肉AMPK活性及能量代谢研究

为了研究不同海拔高度生长的牛宰后牛肉一磷酸腺苷活化蛋白激酶(AMPK)活性与糖酵解指标,以探讨宰后肌肉生理机理,测定了玉树牦牛(海拔4 500 m)、甘南牦牛(海拔3 000 m)和西门塔尔杂交肉牛(海拔1 500 m)宰后成熟过程中牛肉AMPK活性、AMPK基因(PRKAA1、PRKAA2)mRNA表达量、糖酵解和能量代谢的变化。结果表明,12~168 h时间内,AMPK活性从小到大依次为西门塔尔杂交牛、甘南牦牛、玉树牦牛;西门塔尔杂交牛PRKAA1基因的表达量比甘南牦牛和玉树牦牛略低;西门塔尔杂交牛PRKAA2基因表达量显著小于甘南牦牛和玉树牦牛(P0.05);72~168 h时间内,乳酸含量和游离葡萄糖含量从小到大依次为西门塔尔杂交牛、甘南牦牛、玉树牦牛,p H值、肌糖原含量从大到小依次为西门塔尔杂交牛、甘南牦牛、玉树牦牛;成熟前期ATP、ADP、AMP含量从大到小依次为西门塔尔杂交牛、甘南牦牛、玉树牦牛。高海拔品种牛肉机体PRKAA1和PRKAA2基因表达量高时,AMPK被激活从而活性增加,ATP的浓度水平降低,AMP生成量增加,加速组织内的糖酵解,增加肌肉乳酸含量,降低p H值,进而影响牛肉品质。     

当前繁育肉牛养殖中存在的问题与解决对策

当前随着人们生活水平的提高,对饮食的需求层次随之提高,对牛肉的需求量也愈加的旺盛。而现阶段,我国肉牛养殖业的发展尚且存在很多的问题,如销售量的不足、附加利润较低等都是肉牛养殖中存在的问题。因此,亟待找到合理的方式解决肉牛养殖中存在的问题,以促进该行业的发展。     

Effects of traditional salt placement and strategically placed mineral mix supplements on cattle distribution in the Western Italian Alps

Effects of traditional salt placement (TS) and strategically placed mineral mix supplements (MMS) on cattle distribution were compared in the Italian Alps. Salt was placed within flat and herbaceous sites following the traditional method of farmers, whereas MMS blocks were placed on steep and shrub‐encroached sites within three large pastures (44 ha on average). Each TS and MMS site was paired with a control site, and eleven cows were tracked with GPS collars. Within 10 and 50 m of TS and MMS, treatment sites were used more than control sites (P < 0·05). No differences were detected (P > 0·05) in the number of visits by cows within 10 and 50 m of TS and MMS placements. No differences were detected in time spent within 10 m of TS and MMS placements, but cows spent more time (P < 0·05) within 50 m of TS. With either TS or MMS, cattle preferred areas with gentler terrain, higher forage pastoral value and closer to water (P < 0·001). When MMS was available cattle also preferred areas near MMS (P < 0·001). Shrub and herbaceous cover decreased near MMS placements (P < 0·05) from cattle grazing and trampling. Placement of MMS is a promising tool to enhance cattle distribution and potentially reduce shrub encroachment in rugged mountain pastures.     

Sodium fluorescein as an internal tracer on the location of bovine urine patches in pastures

Sodium fluorescein (SF) was evaluated and validated as an internal marker in cattle for the location of urine patches in pastures. Three trials were carried out aiming at the following: evaluating the effect of dilution and volume of application on SF fluorescence on the environment; testing dosages and duration of excretion of SF administered orally to cattle; and validating the methodology for SF use on the location of cattle urine patches in pastures. The marker was tested in beef cattle kept on pastures under three grazing systems: degraded pasture under extensive management (De), intensively managed dryland pasture with high stocking rate (Id) and intensively managed irrigated pasture with high stocking rate (Ii). Besides the localization of urination sites, the number of urinations/animal/d and the area covered by urine were also determined. The residue of SF remained fluorescent in the pasture foliage up to 34 h after urination events, allowing the location of urine patches by a black‐light flashlight. There was no difference between grazing systems in the number of urine patches/animal/d during the rainy and dry seasons. The average number of urine patches was approximately 11/animal/d. As expected, the estimated volume and area covered by urine varied according to the stocking density. The chosen SF dose (50 mg kg^?1 LW) did not adversely affect the animals when administered once daily during 2 d. However, the same SF dose administered during four consecutive days caused urinary disorder in the animal. The distribution of urine patches was spatially dependent on specific characteristics of the paddock.     

中西药结合治疗肉牛尿素中毒效果分析

根据肉牛尿素中毒临床症状表现的不同,结合血氨浓度的检测,对尿素中毒程度不同的肉牛采用了不同的西药进行治疗,同时辅以中药方剂配合治疗。试验结果表明,16头出现明显尿素中毒症状的患牛经中西医结合治疗后痊愈。由此可见,中西药结合治疗肉牛尿素中毒效果理想,值得在临床实践中推广。     

甘肃省市售牛羊肉中雌激素残留状况分析

以甘肃省兰州市、靖远县、临夏州、张掖地区牛羊肉为试验材料,分析了甘肃省市售牛羊肉中己烯雌酚、雌二醇、戊酸雌二醇和苯甲酸雌二醇等4种雌激素残留状况。结果表明,80份样品中(4个地方牛羊肉各10份)所测定的4种雌激素均未检出,甘肃省市售牛羊肉中无论是天然的雌二醇还是己烯雌酚、戊酸雌二醇和苯甲酸雌二醇3种人工合成雌激素均没有残留。     

大豆素对肉牛瘤胃发酵功能的影响

试验旨在研究日粮中添加大豆素对锦江黄牛瘤胃发酵的影响。选取3头健康且安装有永久性瘤胃瘘管的锦江黄牛,采用自身对照设计,试验分对照期和试验期,大豆素添加量500 mg/kg精料。结果表明:1)添加大豆素能使试验期牛瘤胃各时间点p H值显著低于对照期(P=0.036),且在正常瘤胃p H范围内;2)添加大豆素能提高瘤胃液中TVFA、丙酸、丁酸、乙酸浓度及乙酸/丙酸比值,但差异不显著(P﹥0.05);3)添加大豆素使试验期牛各时间点NH3-N浓度较对照期显著降低(P=0.002);4)添加大豆素能使试验期牛微生物蛋白(MCP)合成量较对照期有提高趋势(P=0.053)。综合分析表明大豆素具有改善瘤胃发酵功能作用。     

对我国肉牛及其产品溯源的编码规则设计的初步建议

建立肉牛及其加工分割产品的质量安全可追溯体系,是满足消费者的知情权、选择权与政府监管的重要技术手段。考虑到我国肉牛的饲养模式以散养为主,对责任主体的溯源尤为突出。因此,提出的肉牛个体的15位编码中纳入了养殖场或养殖户的编码,该编码既考虑了与农业部67号令的兼容性,又对后8位的编码赋予了新的定义。此外,采用电子标识的、先赋码的方法,利用数据库记录电子标识码与佩带牛只的关联关系,针对大规模的饲养场也不失为一种行之有效的编码及标识方法。对牛肉分割产品的标识,既可以采用符合欧洲物流编码规则的EAN·UCC 32位条形码,满足肉牛产品进入国际物流市场的技术需求,也可用自行定义的22位终端分割码即产品溯源码,将产品溯源码通过计算机系统与屠宰的牛只个体或者小群体建立关联,基本能实现对牛肉终端产品向屠宰环节及养殖环节的反向溯源。     

基于Panel Nerlove模型的我国牛肉供给反应实证分析

从牛肉供给的角度出发,依据2000-2012年全国29个地区的数据,采用Panel Nerlove经典模型及扩展模型,对我国牛肉市场的供给反应进行分析。结果表明,牛肉的短期供给弹性为0.171,长期供给弹性为0.615,小于1,是缺乏弹性的畜产品;滞后一期牛肉产量、滞后二期牛肉产量、滞后一期牛肉价格、羊肉价格对牛肉产量都有显著的影响。剖析了我国牛肉价格缺乏弹性的原因,并且基于此结论,提出一些发展我国肉牛产业的建议：国家应该在贸易谈判过程中有意识的保护国内肉牛产业,重点要扶持能繁母牛的养殖,重视国内饲草资源的开发和利用。