环境温湿度对奶牛血清生化指标影响的研究

本试验以荷斯坦奶牛为试验对象,研究不同环境温度、湿度下对奶牛血清生化指标的影响。结果表明：随着环境温度的逐渐下降和舍内湿度的升高,血清TP、Glu含量显著升高（P〈0．05）,血清ALB含量明显下降,血清BUN含量呈波动性变化;血清Ca含量显著下降,血清P含量在舍外-2.5℃时最低,以后随着温度的进一步降低而显著升高。本试验说明奶牛血清中的某些生化指标可随环境温湿度的变化而变化。     

荷斯坦奶牛连续超数排卵的研究

为探讨奶牛连续超数排卵的效果,对28头荷斯坦奶牛以不同的FSH剂量(400、380、360 mg),以30 d为间隔连续超排3次。结果表明,每组中各次间头均可用胚数差异不明显;400 mgFSH组与380 mgFSH组头均可用胚数差异不明显,但与360 mgFSH组存在差异,380 mg FSH组与360 mg FSH组存在差异;以400 mg和380 mg FSH进行连续3次超数排卵,都可取得满意效果,但以400 mgFSH为最佳连续超排剂量。     

生物转化富铁、富锌、富硒鲜奶的研究

通过在奶牛饲料中添加微量元素铁、锌、硒，观察它们对奶牛产奶量、产奶品质以及牛奶中所含矿物质及微量元素的变化。结果表明：奶牛饲料中添加上述微量元素后，产奶量明显提高。且鲜奶中所含的铁、锌、硒都有不同程度的增加。     

子宫内膜炎母牛子宫匀浆IL-2、IL-6、IL-8、TNF-α水平

选用正常子宫标本19例和患子宫内膜炎子宫标本66例,并对其进行分类,测定子宫匀浆中细胞因子IL-2、IL-6、IL-8、TNF-的含量,探讨IL-2、IL-6、IL-8、TNF-变化与子宫内膜炎的关系。结果表明,试验组IL-2、IL-6、IL-8、TNF-的含量均高于对照组(<0.05或<0.01),表明子宫内IL-2、IL-6、IL-8、TNF-含量变化与母牛子宫有无感染,以及免疫状态密切相关。     

日粮对奶牛生产性能及经济效益的影响

60头中国荷斯坦奶牛饲喂4种不同紫花苜蓿干草配比、不同精粗比的日粮,以研究日粮配方对奶牛生产性能、经济收益的影响,确定最佳日粮配方。试验结果说明,大比例紫花苜蓿干草(紫花苜蓿=24%DM)、低精粗比(40:60)日粮极显著提高乳脂率(P<0.01);日粮营养水平提高,产奶量提高(P<0.05;P<0.01);最佳经济效益日粮为含大比例紫花苜蓿、精料比例低、营养水平较低的日粮(P<0.01);在低的精粗比例下,紫花苜蓿干草不是日粮成本的限制因素,而青贮饲料配比为日粮成本的限制因素。合理安排精粗比例,适当使用紫花苜蓿干草,可提高奶牛饲养经济效益。     

RPLM对泌乳后期奶牛血液代谢物、产乳量和乳成分的影响

选用 8头经产荷斯坦种乳牛 ,分为对照和瘤胃保护赖氨酸 蛋氨酸 (RPLM )组 ,以二乘反转法 ,研究了RPLM对泌乳后期奶牛瘤胃发酵、血液指标、产乳量和乳成分的影响。对照日粮中添加 10 0 g/d保护材料 ,RPLM组日粮中添加 10 0g/d含Lys 11 6g、Met 4 7g的保护制品。RPLM组与对照组比较 ,血浆游离Lys、Met浓度略有增加 (P >0 1) ,血浆葡萄糖浓度有增加趋势 (P <0 1) ,干物质采食量无明显变化 ,乳量和 4%的标准乳量分别增加 0 5kg/d(2 2 %)和 0 8kg/d(3 5 %) ,乳蛋白率、乳脂率和乳糖率均略高于对照组 (0 0 1%0 0 6%) ,乳蛋白质和乳脂肪生产量分别增加 2 0g/d和 40 g/d ,饲料蛋白质转化为乳蛋白质的效率提高5 9%,但均无明显差异 (P >0 1)。以上结果表明 :泌乳后期奶牛日粮中添加瘤胃保护赖氨酸和蛋氨酸 ,没有明显地提高产乳量和改善乳成分的效果。     

用重组的牛巴贝斯虫棒状体蛋白1作为ELISA诊断抗原进行牛群中牛巴贝斯虫病的血清流行病学调查

用重组的牛巴贝斯虫棒状体蛋白1（Bc—RAP-1）作为ELISA诊断抗原,对采自青海省湟中县的120份奶牛血清样品,进行抗Bc—RAP-1特异性抗体的检测。结果检出7份阳性,阳性率为5．83％,说明该地区牛群存在牛巴贝斯虫的感染。     

黑白花奶牛体尺性状与产奶量之间的多元分析

 本文据119头初产母牛的产奶性能、体高、体长、胸围及体重资料,用微机作了产奶量与体尺性状间的多元回归分析,并建立了体尺性状及体重与产奶量之间的多元回归方程。经F检验,该回归方程极显著。其中,胸围与产奶量之间的关系最为密切,其次是体长和体高;产奶量与体重之间存在极微弱的负相关。作者还分析了该牛群体型方面存在的一些问题,并提出了今后育种工作中应采取的措施。     

基于电参数与神经网络的奶牛乳腺炎检测方法

通过准确测量奶牛新鲜乳汁的温度、电导率、电容和乳汁中的体细胞含量,建立了温度、电导率、电容为输入,体细胞数为输出的四层BP神经网络模型。并将结果与没有电容参数的网络模型结果进行比较。结果表明:电容参数的加入使检测精度有显著提高,验证集奶牛乳腺炎等级的正确检出率达到100%。     

Prevalence,quantitative load and genetic diversity of Campylobacter spp. in dairy cattle herds in Lithuania

Background

Campylobacteriosis is a zoonotic disease, and animals such as poultry, pigs and cattle may act as reservoirs for Campylobacter spp. Cattle shed Campylobacter spp. into the environment and they can act as a reservoir for human infection directly via contact with cattle or their faeces or indirectly by consumption of contaminated food. The aim of this study was to determine the prevalence, the quantitative load and the genetic strain diversity of Campylobacter spp. in dairy cattle of different age groups.

Results

Faecal samples of 200 dairy cattle from three farms in the central part of Lithuania were collected and examined for Campylobacter. Cattle herds of all three farms were Campylobacter spp. positive, with a prevalence ranging from 75% (farm I), 77.5% (farm II) to 83.3% (farm III). Overall, the highest prevalence was detected in calves (86.5%) and heifers (86.2%). In contrast, the lowest Campylobacter prevalence was detectable in dairy cows (60.6%). C. jejuni, C. coli, C. lari and C. fetus subsp. fetus were identified in faecal samples of dairy cattle. C. upsaliensis was not detectable in any sample. The high counts of Campylobacter spp. were observed in faecal material of dairy cattle (average 4.5 log₁₀ cfu/g). The highest numbers of Campylobacter spp. were found in faecal samples from calves (average 5.3 log₁₀ cfu/g), whereas, faecal samples from cows harboured the lowest number of Campylobacter spp. (average 3.7 log₁₀ cfu/g). Genotyping by flaA PCR-RFLP analysis of selected C. jejuni isolates showed that some genotypes were present in all farms and all age groups. However, farm or age specific genotypes were also identified.

Conclusions

Future studies are needed to investigate risk factors related to the degree of colonisation in cattle. Based on that, possible measures to reduce the colonisation and subsequent shedding of Campylobacter in cattle could be established. It is important to further investigate the epidemiology of Campylobacter in the cattle population in order to assess associated risks to public health.