中国荷斯坦牛部分乳房结构特性对泌乳性能的影响

本研究对规模化场奶牛乳房结构部分性状进行评价和测定,旨在分析其影响因素及其与泌乳性能的关系。现场评价和测定我国北方6个规模化奶牛场荷斯坦牛的乳房均衡(2 030条)、乳头长度(1 551条)和乳头位置评分(分前、后乳头,2 839条),使用SAS 9.2 GLM过程采用固定效应模型分析影响上述3个乳房性状的因素,同时分析3个单项性状对校正日产奶量和体细胞评分的影响。结果表明:场和胎次对3个乳房性状影响极显著(P0.01);前、后乳头位置和后乳头长度对校正日产奶量有显著影响(P0.05),校正日产奶量与前乳头位置评分值呈正比,与后乳头位置评分值呈反比;前乳头位置和长度对体细胞评分有显著影响(P0.05),体细胞评分随前乳头位置评分的增大而减小;5~5.5 cm的乳头长度对于校正日产奶量和体细胞评分都最佳。本研究结果为通过乳房性状选择、淘汰并提高奶牛的生产性能、乳房健康提供了参考。     

奶牛乳头专用消毒剂消毒效力研究

通过对MEDPH奶牛乳头专用消毒剂进行实验室消毒试验、现场消毒试验及同类产品的对比试验,测定了其杀菌效果。实验室消毒试验表明,MEDPH奶牛乳头专用消毒剂使用液(含有效碘0.04％)对大肠杆菌、金黄色葡萄球菌、溶血性链球菌的最低杀菌浓度分别为0.01％(使用液4倍稀释)、0.01％(使用液4倍稀释)、0.02％(使用液2倍稀释);最快有效时间为15s,杀菌率达99.99％,杀灭指数大于10 4。现场消毒试验表明,该消毒剂使用液对奶牛乳头表面细菌杀菌率达99.99％,杀灭指数大于10 4,且对奶中乳头无不良反应,安全可靠。对比试验表明:其杀菌效果和使用效果均优于"碘伏",与"滴宝"效果相当。     

Dry cow therapy with a non-antibiotic intramammary teat seal - a review

: Dry cow antibiotic therapy is used to eliminate existing intramammary infections and to prevent new infections in the dry period. It is implemented as part of a total management system known as the 'Five-Point Plan' for mastitis control. Recent public concerns over the widespread prophylactic use of antibiotics, coupled with an increasing interest in organic farming, have lead to a re-evaluation of the treatment of cows at drying-off. As a result, attention has focussed on the use of novel alternatives to antibiotic therapy at the end of lactation. One such therapy involves the application of a non-antibiotic bismuth-based intramammary teat seal designed for use in cows with low cell counts at the end of lactation. Like the keratin plug that forms naturally in teats of cows that have been dried-off, teat seal forms a physical barrier to invading pathogens. To date, a number of independent studies have shown that teat seal is as effective as traditional dry cow antibiotic products in preventing the occurrence of new infection during the dry period in cows with somatic cell counts of ≤200,000 cells ml-1 at drying-off. This paper reviews the efficacy of teat seal in preventing dry period mastitis in both conventional and organic dairying systems.     

仔猪出生顺序、出生重、性别对乳头序列确定及增重的影响

主要研究仔猪出生顺序、出生重、性别等因素对乳头序列确定以及一周龄仔猪增重的影响。试验发现仔猪乳头序列的固定时间在不同窝之间存在很大差异,乳头固定受诸多因素的影响。固定过程中仔猪可能会改变偏好乳头,仔猪越频繁的更换乳头就越难固定乳头。出生重较大的仔猪初次确定偏好乳头的时间和乳头序列最终固定的时间都较短,并且增重明显较多。出生顺序、性别对乳头序列影响不显著,对仔猪增重的影响也不明显。     

撒坝猪乳头数遗传力及其与繁殖性能关系的研究

本研究对 4个世代共 577头撒坝猪的乳头数进行了分析 ,并用HARVEY程序对乳头数的遗传力进行了估计 ,同时利用 1 2 8头有繁殖性能记录的母猪资料对乳头数与繁殖性状的关系进行了分析。结果表明 ,各世代的乳头数存在着显著差异 ,且逐代均有显著提高 ;乳头数的遗传力为 0 .331 ;乳头数与总产仔数和活产仔数间遗传相关和表型相关均为负值 ,与初生窝重、2 0日窝重、断奶仔数和断奶窝重间则存在着正的遗传相关和表型相关 ;乳头数与所有繁殖性状的环境相关都较弱 ( -0 .0 0 2～ 0 .0 94 )     

霜状结冰及其对机翼气动特性影响的数值模拟

通过对MEDPH奶牛乳头专用消毒剂进行实验室消毒试验、现场消毒试验及同类产品的对比试验,测定了其杀菌效果。实验室消毒试验表明,MEDPH奶牛乳头专用消毒剂使用液(含有效碘0.04％)对大肠杆菌、金黄色葡萄球菌、溶血性链球菌的最低杀菌浓度分别为0.01％(使用液4倍稀释)、0.01％(使用液4倍稀释)、0.02％(使用液2倍稀释);最快有效时间为15s,杀菌率达99.99％,杀灭指数大于10 4。现场消毒试验表明,该消毒剂使用液对奶牛乳头表面细菌杀菌率达99.99％,杀灭指数大于10 4,且对奶中乳头无不良反应,安全可靠。对比试验表明:其杀菌效果和使用效果均优于"碘伏",与"滴宝"效果相当。     

Use of ultrasound scanning to estimate teat wall thickness in Murciano-Granadina goats

To evaluate the ultrasound technique as a method for estimating the effect of mechanical milking on teat thickness in Murciano-Granadina goats, the following work was carried out with a twofold objective: (1) to study the most suitable ultrasound exploration frequency for this breed and the effect of the operator in applying the technique and (2) to validate the approach, comparing it with measurements taken by another estimation method (cutimeter) and performing ultrasound examinations in cows using the same methodology. To this end, three studies were designed. In the first study, 2 experiments were carried out: (a) the first (E1) tested the frequencies 5, 7.5 and 10 MHz; (b) the second (E2) tested the frequencies 3.5 and 5 MHz. In the second study, 2 different independent operators (OP) performed sonography on the same animals (E3), chose the best image of ultrasound examinations recorded as a video sequence (E4) and carried out measurements on ultrasound images (E5). In the third study, the technique tested in goats was applied in 10 Holstein cows (E6) and, finally, ultrasound scans were performed at 5 MHz frequency and cutimeter measurements taken in 63 goats (E7).     

Effect of vacuum level on milking efficiency, somatic cell counts (SCC) and teat end wall thickness in ewes of Greek mountain Boutsiko breed

The aim of this work was to determine the effect of vacuum level of machine milking on milk yield, milk composition, milking efficiency, somatic cells counts (SCC), and teat end thickness of the Greek mountain breed Boutsiko ewes. Seventy two ewes after a suckling period of 45 ± 5 days were divided into three equal groups of 24 animals for level of milk production, prolificacy and lactation number. The overall experiment lasted 14 weeks. All groups were milked with a pulsation rate of 120/min, pulsator ratio of 50/50, and three vacuum levels of 38, 44 and 50 kPa, respectively, were applied for the three groups. Every two weeks, in a.m. and p.m. milking, measurements were taken for machine milk (MM) and machine stripped milk (MSM), milk composition, SCC, milk emission characteristics (only in a.m. milking) and teat end wall thickness (TEWT) before and after milking. The results have shown that the lower vacuum level of 38 kPa increased (P < 0.05) the percentage of machine milk (82.9%). There were no significant differences among the groups for milk composition, milk flow rate and SCC, but there was a difference in log SCC (P < 0.05) between 38 and 50 kPa. The teat end wall thickness was lower at the lower vacuum level (38 kPa) after milking, and increased (P < 0.001) as the vacuum level was raised to 50 kPa. The findings of this study suggest that with a lower vacuum level of 38 kPa, the ewes are milked better than those with 44 or 50 kPa. Also, the irritation of teats is considerably reduced, while no differences were seen regarding the health of the udder.