奶牛和肉牛日粮淀粉和葡萄糖的营养调控及其评定的建议

谷物饲料干物质中的淀粉含量多在50%以上,全株玉米青贮的淀粉含量亦有30%。牛的玉米日粮生淀粉消化率比熟淀粉低,但熟淀粉由于瘤胃消化率很高,所以瘤胃后的可消化淀粉量很低。生糖前体能量(瘤胃丙酸 肠可消化淀粉)能明显提高产奶量和乳蛋白率,但导致乳脂率下降。须对生糖前体能量进行评定和调节,以提高产奶效率。对真胃灌注不同梯度的葡萄糖或淀粉均显着地提高了Kf和体脂肪及体蛋白质沉织,因此我国肉牛饲养标准提出的Kf(%)=11.7645 55.756(IDOM/FNDF)仍适用,但可进一步增加IDOM中的淀粉调控。     

Effects of growth hormone treatment on the expression of somatotropic axis genes in the skeletal muscle of lactating Holstein cows

This study focused on the expression of somatotropic axis genes in the skeletal muscle of dairy cattle. A slow-release recombinant bovine growth hormone (GH) (rbGH) formulation was administered to 5 cows, and saline solution (control) was administered to another 5 cows every 2 wk for a total of 10 wk, starting from the peak of lactation. Tissue and blood samples were collected on days 2 and 14 after each rbGH injection. As target genes insulin-like growth factor (IGF)-1, IGF-2, IGFBPs (1, 2, 3, 4, 5, 6), acute labile subunit (ALS), IGF-1 receptor (IGF-1R), GH receptor (GHR), and the known GHR 5′-UTR variants were selected as target genes, and their relative expression was measured using real-time polymerase chain reaction. In GH-treated cows, an increase in expression was observed for GHR 5′-UTR variant 1I on day 14 (P < 0.05), whereas a significant down-regulation of GHR (P < 0.05) was found after comparing values of treated cows between day 2 and day 14. However, only IGF binding proteins (BP)-5 was found to be appreciably up-regulated in GH-treated cows (P < 0.001), which may indicate the importance of this gene in the overall molecular response to GH administration. Our study indicated that GH treatment did not affect the expression of most somatotropic axis genes, despite the marked increase in GH and IGF-1 in blood (P < 0.001). Nor did it have a large impact on the proportion of GHR 5′-UTR variants in the skeletal muscle of lactating cows. Finally, although we observed a significant variation in the expression of some genes, it would appear that the differences between GH-treated cows and controls were not great enough to be considered as reliable indirect indicators of GH treatment in dairy cattle.     

宏基因组NGS技术在肉牛疫病检测中的应用研究

为调查新疆昌吉州区肉牛主要疫病病原,本试验应用mNGS宏基因组测序技术,对昌吉州地区的肉牛养殖场、活畜交易市场和屠宰场中表现不同临床症状的46份病样进行检测,结果检出病毒、细菌,血原虫病和支原体等78种病原,结合当前国内外肉牛养殖过程中已经报道和流行的病原,与宏基因组检测的46份临床病例样品的检测出的进行临床比对,筛查出细菌13种、病毒13种,以及支原体、血原虫等其他病原4种,共计30个主要病原,为新疆昌吉肉牛养殖疫病综合防控技术的研究提供科学的数据支撑。     

Accounting for numbers of expressions of specific genotypes using a modified gene-flow method

The objective of this study was to develop a modified discounted gene-flow method and calculate numbers of cumulative discounted expressions (CDE) and value of using a Japanese Black cattle bull carrying specific alleles of interest. The discounted gene-flow method was modified to consider not only parent's genotypes but also the allele frequency in the herd. Input parameters representing a typical situation in a Japanese Black cattle herd were used to calculate the CDE and the value of using sires genotyped for recessive genes assuming biallelic loci (A and a) and a herd at Hardy–Weinberg equilibrium. The quantitative trait assumed was marbling and the effect of genotype aa was 1 Beef Marbling Standards (BMS) above that of an animal with either genotype Aa or AA. The effects of gene frequency and discount and survival rates on the CDE were determined for different genotypes of sires. Benefits from using either aa sires or Aa sires above that of using unknown sires at various gene frequencies were also determined. The CDE of aa sires were larger than those of Aa sires under all gene frequencies. The differences in the CDE between aa and Aa sires ranged from 34% at gene frequency of 0.7 to 71% at gene frequency of 0.01. An increase in the discount rates and a decrease in survival rates were associated with a decrease in expressions in cases using aa and Aa sires. The benefits of using aa sires were high when the gene frequency in the herd was 0.5. The benefit of aa sires were approximately 3023 yen more than that for unknown sires in the population when the gene frequency was 0.5. At gene frequencies higher than 0.5, use of Aa sires was not beneficial. This study has demonstrated how the gene frequencies in the herd and the genotypes of sires are critical in determining the benefits of using single recessive gene in the Japanese Black cattle.     

我国肉牛产业发展的几个问题

文章阐述了我国养牛业发展从役用向肉用的转变历程,并根据国情和现存国家级种公牛站(45个)中的牛群品种结构状况,提出了培育我国肉牛品种的途径。     

肉牛分子育种的研究进展

分子生物学的发展,使人们能够从分子水平上探讨肉牛的育种.本文综述了肉牛遗传资源的保护和利用、基因组学和转基因技术的研究现状和进展,着重阐述了肉牛基因图谱的构建和数量性状基因座的检测与利用,同时指出肉牛分子育种的前景和存在问题.     

固原市原州区肉牛改良工作调查研究

调查了宁夏固原市原州区肉牛改良工作开展情况,测量了区内67头繁殖母牛的体尺,利用肉用指数(Beef purpose index,BPI)研究了牛群的经济类型。结果表明:利秦F_1和西秦F_1的繁殖母牛平均BPI分别达到3.40和3.42,比纯种秦川牛提高了12.21%和12.87%,改良效果显著(P<0.05),利秦F1和西秦F1改良效果无明显区别(P>0.05)。     

关于牛胴优质分割肉块名称的讨论

随着优质肉牛生产技术的示范与推广，肉牛产业化蓬勃发展，但在生产过程中，很多牛胴优质分割肉块名称使用不太规范，亟待统一名称，以促进全国肉牛业的进一步发展。     

我国牛肉产量级制度建立的借鉴与思考

完善的牛肉分级体系一般都包括质量等级标准和产量等级标堆。产量等级主要描述胴体的产肉性能，如产肉率等，与胴体重、背膘厚，眼肌面积以及胴体的厚度等指标密切相关。文中详知介绍各国产量等级标准，对我国产量等级标准的制订提出一些建议。     

奶牛双胎的发生及其对奶业生产的影响

奶牛在一个发情周期内如果同时排出两个成熟卵子，经过受精和发育，就可能出现双胎现象。奶牛双胎的发生与遗传、产奶量、胎次、受孕年份和季节等因素有关。由于奶牛双胎出现了异性孪生母犊不育、胎衣不下率升高、胎间距延长、流产率和难产率升高、胎儿成活率降低等负面影响。因此，奶牛双胎对奶业生产是不利的。如果能结合性别控制等先进技术，奶牛双胎将有很大的发展前景。     

不同营养水平对肉牛肥育效果的研究

为了探索酒泉地区舍饲肉牛的肥育模式,用3个不同营养水平的精料对62头小公牛进行了肥育试验,并从日增重、耗料量和经济效益3方面进行了分析.结果表明:3个营养水平对肉牛日增重差异不显著,中营养组日增重略高于其它两组;从耗料情况来看,高营养组耗料最多,中、低营养组耗料基本相同;从经济效益看,中营养组最好,高营养组最差.综合分析表明在酒泉地区肥育肉牛应以中等营养水平为宜.     

生长肉牛的氨基酸需要量研究进展

研究反刍动物氨基酸需要量的最常用方法为屠体氨基酸分析法和真胃或十二指肠灌注法 ,研究者们采用不同的方法研究了肉牛的氨基酸需要量。在生长肉牛的实用日粮条件下 ,蛋氨酸或赖氨酸常为第 1限制性氨基酸     

我国发展肉牛产业的SWOT分析

肉牛产业已形成了肉牛育种、饲料生产、肉牛繁育、肉牛育肥、牛肉加工、销售餐饮等各环节相互联动、协调发展的成熟产业运作模式,成为了实现循环经济的重要支柱产业,以及发展区域经济和农民增收的新亮点。文章应用SWOT分析方法,对我国发展肉牛业的优势、劣势、机遇和挑战进行了深入剖析。     

奶牛急性乳腺炎病原菌的分离与鉴定研究

对6头患有急性乳腺炎奶牛的24个乳区进行细菌的分离培养和初步的生化鉴定,检出葡萄球菌7株,无乳链球菌6株,大肠杆菌10株,棒状杆菌2株,分别占细菌检出数的28%,24%,40%,8%。     

一起肉牛球虫病的诊治

2020年5月,河南南阳某养殖场发生以血痢为主,常规治疗无效的情况。随即进行临床初步诊断并采集新鲜粪便样品进行实验室检测,结果显示为球虫感染引起的腹泻。经综合治疗,病情得到有效控制。     

内蒙古三河牛牛肉挥发性风味物质分析

旨探寻内蒙古三河牛牛肉风味特征物质,分析不同部位生牛肉中挥发性风味物质种类和含量,以期探索牛肉挥发性风味物质在牛肉中的作用机理。采集呼伦贝尔农垦集团三河牛牛肉16个部位共计48份样品,采用固相微萃取技术联合气相质谱分析仪（SPME-GC-MS）对三河牛牛肉中挥发性风味物质进行分析研究,挥发性组分通过与NIST20谱库及正构烷烃标准物质进行比对进行定性分析,且正反匹配度均大于800（最大值为1000）的鉴定结果予以确认,通过峰面积归一化法计算各组分的相对含量。结果表明,16个部位中挥发性风味化合物检测出7大类共159种主要挥发性风味物质,其中醛类化合物32种,醇类化合物21种,酸类化合物16种,烃类化合物37种,酯类化合物33种,酮类化合物10种和杂环类化合物11种。三河牛肉质氨基酸含量高、风味口感都非常好,是生产肉制品的高端原料。     

陈仓区肉牛产业发展的调查与思考

作者通过调查陈仓区的肉牛产业现状,指出了产业发展中存在的问题,分析提出了规模肉牛养殖的建议,旨在为肉牛产业带提供参考意见。     

饲料中不同钼铜水平对肉牛血铜代谢规律的研究

选择4头年龄、体重相近的健康利木赞与鲁西黄牛杂交公牛.试验分低钼期(钼浓度即正常情况下不加钼)和高钼期(添加钼浓度为5 mg/kg)两个阶段进行.结果表明:低钼水平下,铜添加10、25和50 mg/kg时血铜水平在0.97～1.18mg/kg之间,血铜含量变化不显著.说明10 mg/kg的铜添加浓度就可满足牛的需要.高钼水平下,血铜含量随铜添加量的增加而变化较大,加10 mg/kg铜时血铜水平在0.8 mg/kg以下,不能满足牛的需要.当添加量达25 mg/kg和50 mg/kg时,血铜水平上升到1.0 mg/kg左右,可满足牛对铜的需要并能保持基本恒定,且添加25 mg/kg和50 mg/kg铜时牛的血铜无差异,证明高钼时添加25 mg/kg最为经济.     

皮西黄、德西黄三元杂交试验效果研究

研究在农户舍饲养条件下测定并对比研究了皮西黄、德西黄三元杂交牛及西黄二元杂交公牛各6头4月龄、6月龄、12月龄和18月龄的生长发育指标.结果表明:三元杂交牛18月龄活重达400kg以上,比二元杂交牛提高14.3%～20.4%;体高提高5.3%～10.8%,体斜长提高13.4%～16.7%,胸围提高19.2%～22.4%,管围提高6.5%～17.1%.三元杂交牛其它各年龄段比二元杂交牛体尺、体重均有大幅度的增长,故以上两种杂交组合是适宜当地发展肉牛生产的较佳杂交组合.