Supplementation of dairy cows with a fish oil containing supplement and sunflower oil to increase the CLA content of milk produced at pasture

It has been shown that the cis 9, trans 11 isomer of conjugated linoleic acid (CLA) can be increased in milk by supplementation with fish oil and vegetable oils. Feeding a high level of oil, however, can impact negatively on gross milk composition. The principal aim of this study was to determine if relatively low levels of fish oil or sunflower oil, either alone or in combination, offered to dairy cows on pasture would increase the C18:2 cis 9, trans 11 CLA concentration in milk. Forty autumn-calved cows on a diet of grazed grass were assigned to 4 supplementation treatments: (i) No supplement (P), (ii) 255 g/day of sunflower oil (SO), (iii) 255 g/day of sunflower oil + 52.5 g/day of fish oil (SOFO), and (iv) 105 g/day of fish oil (FO). The fish oil was supplied in a proprietary product called Omega-3 Supplement which is a mixture of marine oils and an extracted oilseed meal and contains 500 g/kg of oil. The oils were fed in a concentrate mixture, which was offered at a rate of 3.0 kg/cow per day. The production of the cows was measured for 54 days and the milk fatty acid composition was determined on day 0 (immediately before the supplements were introduced) and on days 14, 28 and 42 after the treatments were imposed. Supplementation increased the yield of milk (P < 0.01), protein (P < 0.05) and lactose (P < 0.001), decreased milk fat (P < 0.05) and protein (P < 0.01) concentrations and increased (P < 0.01) lactose concentration. Type of oil did not significantly affect any production variable. The concentration of C18:1 trans 9 + C18:1 trans 11 (mainly C18:1 trans 11) (P < 0.001) and C18:2 cis 9, trans 11 CLA (P < 0.01) were greater on supplemented treatments than on P and the concentration of both were greater (P < 0.05) on FO than on SO. The results confirm that the concentration of C18:2 cis 9, trans 11 CLA can be increased further, from an already relatively high concentration in milk from pasture, by offering supplements containing a low level of fish oil either alone or in combination with sunflower oil.     

宁夏地区不同生长阶段奶牛产污系数的对比分析

选择不同生长阶段的中国荷斯坦奶牛作为试验对象,采用全收粪尿法来研究不同生长阶段奶牛各种污染物特性及产污系数。结果表明:不同生长阶段奶牛体重与其采食量、粪尿产生量大致成二倍正相关关系;P、Cu、Zn元素都主要通过粪便排泄,其中Cu、Zn元素在尿液中含量甚微;单位体重粪或尿污染物产生量无论是从N、P还是Cu、Zn,成年泌乳奶牛对环境的贡献率都要高于育成期奶牛。     

高温高湿条件下添加功能性油脂对奶牛生产性能、瘤胃发酵和生理状态的影响

文章旨在评估功能性油脂替代莫能菌素对高温高湿环境下奶牛生产性能、瘤胃发酵和生理状态的影响。试验选择产奶期(200±50)d,平均体重(600±75)kg的荷斯坦奶牛36头,将其随机分为3组,每组12个重复,每个重复1头牛,进行为期6周的试验(1周适应期,5周试验期),试验共设计3种日粮,对照组饲喂基础日粮,处理1组在基础日粮添加20mg/kg莫能菌素,处理2组在基础日粮添加0.05%功能性油脂。试验期间环境温度、湿度和温湿度指数分别是(25±0.55)℃、(82.0±1.20)%和74.5±0.30,表明奶牛处于高温高湿环境。结果:处理1组较对照组和处理2组显著降低了干物质和有机物的摄入量(P<0.05),较对照组显著降低了粗蛋白质摄入量(P<0.05)。试验时间显著影响有机物、蛋白质摄入量及养分表观消化率(P<0.05),同时显著影响瘤胃pH、氨氮和挥发性脂肪酸含量(P<0.05)。对照组较处理2组显著降低了血清尿素含量(P<0.05),处理和时间对血清尿素含量的影响具有显著交互效应(P<0.05)。处理1组较处理2组显著降低了脂肪产量和乳脂肪含量(P<0.05)。试验时间显著影响乳成分含量及产量(P<0.05)。结论:在本试验条件下,功能性油脂增加了乳脂产量,并且可以代替莫能菌素而不影响奶牛在高温高湿环境下的采食量、养分消化率、瘤胃发酵和生理状态。     

中国荷斯坦奶牛EEF1D基因的SNPs检测及其与产奶性状的关联分析

试验旨在研究中国荷斯坦奶牛真核生物翻译延伸因子1D（eukaryotic translation elongation factor 1 delta,EEF1D）基因的多态性及其与产奶性状的相关性。利用Sequenom MassARRAY SNP分型技术对宁夏地区1 252头中国荷斯坦奶牛EEF1D基因的多态性进行了检测,并对其多态位点不同基因型和组合基因型与产奶性状进行了关联分析。结果显示,EEF1D基因的5'侧翼区存在2个SNPs位点,即EEF1D-1和EEF1D-3;经检测发现,EEF1D-1存在2种基因型,EEF1D-3存在3种基因型。χ²检验表明,中国荷斯坦奶牛在EEF1D-1位点偏离Hardy-Weinberg平衡状态（P < 0.05）,在EEF1D-3位点未偏离Hardy-Weinberg平衡状态（P > 0.05）;EEF1D-1和EEF1D-3位点多态信息含量（PIC）分别为0.10和0.28,分别呈现低度多态和中度多态。在试验群体中,EEF1D-1位点对乳脂率和乳蛋白率性状的效应均达到极显著水平（P<0.01）,对305 d产奶量性状的效应达到显著水平（P<0.05）;EEF1D-3位点对305 d产奶量、乳脂率和乳蛋白率性状的效应均达到极显著水平（P<0.01）;EEF1D基因的优势基因型组合GG-AG和GG-GG个体乳脂率均显著高于GG-AA组合个体（P<0.05）。说明EEF1D基因可以作为影响中国荷斯坦奶牛产奶性状的候选基因用于标记辅助选择。     

奶牛隐性子宫内膜炎诊断技术研究进展

奶牛隐性子宫内膜炎在以子宫内膜被嗜中性粒细胞(PMN)持续性的广泛浸润为主要特征,没有直观的临床症状,经常导致奶牛屡配不孕。在中国,由子宫内膜炎引起的奶牛不孕的比例达50.62%,且由隐性子宫内膜炎引起的奶牛不孕占其中的90%。由于隐性子宫内膜炎在发病初期不易被观察到,容易错过最佳治疗时间,造成巨大的经济损失,故如何对其做出正确、及时的诊断成了近年来的研究热点。目前,国内外奶牛隐性子宫内膜炎的诊断方法主要有阴道内窥镜法、细胞刷法、活体组织诊断法、超声诊断法及白血球酯酶法等,但目前这些诊断方法没有统一的判断标准。本文对几种不同的奶牛隐性子宫内膜炎的诊断方法进行了综述,为更早、更准确地诊断隐性子宫内膜炎提供依据。     

某牛场奶牛A型多杀性巴氏杆菌的分离鉴定

湖北某奶牛场牛群爆发体温升高、呼吸困难、流涎及颈胸皮下气肿等症状的疾病,部分发病牛衰竭死亡,为确诊牛场牛群发病原因并提出防控方案,本试验采集死亡牛的心脏、肝脏、肺脏及气管组织进行病原菌的分离纯化及PCR鉴定,并对鉴定的病原菌进行生化特性鉴定、致病性试验和药物敏感性分析;同时提取患牛血清RNA,开展牛流行热病毒的RT-PCR鉴定。结果显示,病料在类胸膜肺炎固体培养基上不生长,生化特性鉴定显示能形成靛基质、不发酵肝糖和肌醇;牛流行热病毒RT-PCR扩增阴性;所分离的病原菌经16S rRNA及牛A型多杀性巴氏杆菌特异性引物PCR扩增阳性;致病性试验显示该病原可致死小鼠,且能从死亡小鼠体内分离到感染菌;药敏试验结果显示该病菌对头孢哌酮、左氧氟沙星敏感,其他20种临床常见药物表现耐药。综上所述,该牛场患病牛确诊为牛A型多杀性巴氏杆菌感染,建议根据药敏试验结果选择敏感药物,对患病牛进行隔离治疗,疑似患病牛隔离观察,同时加强通风,及时清理污物并消毒,改善饲养管理,避免拥挤、寒冷及长途运输等应激因素。     

Isolation and Identification of Pathogenic Bacteria Causing Dairy Cow Mastitis in Liaoning and Drug Sensibility Test of Pathogenic E.coli

In order to understand the main bacterial pathogen species causing dairy cow mastitis in Liaoning, as well as the characteristics of drug sensitivity of the pathogenic E.coli,the milk samples from 75 dairy cows with clinical manifestations for mastitis in certain large-scale dairy farm in Liaoning were collected.The bacteria in milk were cultured and isolated with biochemical methods and in vitro drug sensitivity tests were processed with the isolated E.coli strains.The results showed that the main bacterial pathogen for dairy cow mastitis were E.coli（separation rate 58.7%),S.aureus（64.0%）and S.agalactiae（54.7%),and multiple infection including double and triple infection were identified.The drug sensitivity tests on the isolated E.coli indicated that the E.coli isolates were highly resistant to sulfonamides（resistance rate>85%）and chloramphenicol（resistance rate>30%),and they were relatively low resistant to ampicillin（9.5%),ciprofloxacin（9.5%),ceftiofur（7.1%）and ofloxacin（4.8%).The results was able to provide reliable theoretical basis for prevention and control of dairy cow mastitis in Liaoning area.     

奶牛秸秆型日粮矿物质营养水平评价

对淄博地区奶牛营养两次调查过程中,发现秸杆型日粮饲喂的奶牛可能存在矿物质缺乏问题。针对这一问题,测定日粮中钙、磷、铜、锰、铁、锌和奶牛血液中铜、锰、铁、锌元素的浓度,用以评价秸杆型日粮奶牛矿物质营养水平。结果表明:①秸杆型日粮存在矿物质营养不平衡问题,锰、锌元素不足,铁元素过剩。②秸杆型日粮矿物质营养具有互补作用。③评价奶牛矿物质营养水平的手段有待改进。     

四川凉山地区奶牛乳房炎主要病原菌分离鉴定及药敏情况分析

通过开展凉山地区奶牛乳房炎主要病原菌的分离鉴定和药敏情况试验,为指导凉山地区奶牛场临床合理使用抗生素以及提高抗生素的防治效果提供理论指导.通过采样、增菌培养、细菌鉴定、药敏试验、数据统计分析等方法,结果发现193份患有乳房炎的乳样中有134份分离出12种病原菌,其中65份检出两种及以上菌,占检出数的48.50％﹔共分离...