奶牛肢蹄病对繁殖性能的影响

奶牛肢蹄病是规模化奶牛场最常见的疾病之一,普遍认为奶牛肢蹄病对奶牛业的经济损失仅包括降低产奶量、增加药物治疗费用和奶牛的淘汰率等,近几年国内外学者报道奶牛肢蹄病对繁殖性能有着不同程度的负面影响。作者就奶牛肢蹄病对卵巢囊肿发病率、卵泡发育、发情行为、首次配种天数、空怀期天数和淘汰率影响的研究情况进行了简要综述。     

提高奶牛繁殖性能的技术发展现状

本文回顾了目前国际上对提高奶牛繁殖力的最新研究进展，从调控卵巢功能促进卵泡的发育和排卵、排卵后的黄体功能及提高胚胎存活力等方面讨论了目前可以用于提高奶牛繁殖性能或受胎率的各项技术研究进展。这些技术包括①促进排卵和定时排卵-输精技术；②在排卵后用GnRH、hCG和干扰素T处理抵抗子宫的溶黄作用，促进黄体功能从而提高受胎率的技术；配种时或早期妊娠阶段通过使用生长激素处理促进胚胎发育和提高胚胎存活率，从而来提高受胎率的技术；③从影响生殖系统功能、卵泡发育和子宫溶黄作用的营养水平各方面发展出来的营养管理技术。今后在这些研究进展的基础上，综合、灵活应用这些技术，发展出实用的提高奶牛受胎率和繁殖性能的技术。     

热应激对奶牛繁殖性能的影响研究进展

环境温度、湿度和光照周期都会对奶牛的繁殖性能造成影响。夏季奶牛采食量减少可能会影响奶牛的能量平衡,或导致下丘脑-垂体-卵巢轴功能紊乱,进而降低卵母细胞、胚胎和卵泡的质量,导致奶牛繁殖性能降低。本文就夏季热应激对奶牛繁殖性能的影响做一综述。     

热应激对奶牛繁殖力的影响及应对措施

炎热的夏季会导致奶牛的繁殖力下降,其原因是由于热应激引起动物机体一系列的异常反应所致。本文通过总结近十几年国内外的研究成果,从内分泌、配子产生和胚胎发育等方面论述了热应激对奶牛繁殖力的影响及可能存在的内在机制,并针对这些影响提出了一系列在奶牛生产中用于缓解热应激和提高奶牛繁殖力的措施,包括常用的奶牛物理降温法、日粮调配、耐热性奶牛的培育,以及具有广阔前景的生物技术等。     

能量摄入水平对围产期健康奶牛生产性能及生殖激素的影响

将30头健康的围产期奶牛随机分为三组，分别于产前28d开始饲喂NRC标准日粮（能量摄入100％组或Ⅰ组）、NRC标准增加20％日粮（能量摄入120％组或Ⅱ组）和NRC标准减少20％日粮（能量摄入80％组或Ⅲ组），产后各组奶牛均饲喂NRC标准泌乳日粮，至产后56d结束，观察干奶期不同能量摄入水平对产后奶牛千物质摄入量（DMI）、泌乳量及生殖激素的影响。试验结果表明：围产期生殖激素的剧烈变化影响奶牛的DMI，泌乳量，糖、脂和蛋白质代谢，并主要通过调整NEFA的去路，适应机体的各种生理变化。干乳期能量摄入水平很可能是通过生殖激素对奶牛的DMI、泌乳和能量平衡进行影响和调节的。     

Reproductive Disorders of Crossbred Dairy Cows in the Central Highlands of Ethiopia and Their Effect on Reproductive Performance

The study was conducted to estimate the proportion of reproductive disorders and to determine factors affecting reproductive performance of crossbred dairy cows under four different production systems in the central highlands of Ethiopia. The principal postpartum reproductive disorders were retained fetal membranes (14.7%) and uterine infection (15.5%). Anoestrus was the major postpartum reproductive problem in the mixed crop–livestock production system (38.6%) and was significantly associated with this production system. Apart from anoestrus, the occurrence of reproductive disorders was not significantly associated with a production system. Most of the reproductive disorders occurred as a complex rather than as a single abnormality. Two or more abnormal conditions were seen in 11.4% of the cases. Each reproductive trait measured was affected adversely by reproductive disorders. Cows with reproductive disorders in each production system, lactation group and suckling and non-suckling group had longer intervals from calving to first service and to conception (p < 0.001) and required more services per conception (p < 0.001). Pregnancy rate and conception to first service were 84.7% and 51.7%, respectively, for cows without reproductive health problems; and 64.2% and 15.1%, respectively, for cows with reproductive disorders (p < 0.001). Overall, intervals from calving to first service were shorter (p < 0.05) than in younger cows. Intervals from calving to first service and to conception were longer in suckling than in non-suckling cows (p > 0.05). Cows with a good body condition score (>3.5) at calving had shorter calving to first service and conception intervals than cows in poor condition (p < 0.001). The results showed that reproductive abnormalities, coupled with poor body condition, are important factors that contributed to reproductive inefficiency. An appropriate reproductive health management, a reliable artificial insemination service and supplementary feeding could be the management options to reduce or alleviate some of the problems.     

硒和VE对奶牛繁殖性能的影响

根据国内外关于矿物元素硒和VE研究进展情况,分析了硒和VE对奶牛繁殖性能的影响。针对目前国内奶牛养殖过程中饲喂矿物质硒和VE的现状与存在问题,提出其在日粮中饲喂与添加的措施,旨在为奶牛养殖场（户）在生产过程中科学合理应用矿物元素硒和VE提供参考,以提高奶牛繁殖性能,增加养殖经济效益。     

不同饲养模式对奶牛健康状况和牛奶品质的影响

为了研究不同饲养模式对奶牛健康状况和奶牛品质的影响,本研究选择三种不同饲养模式下的奶牛各30头,采集血样和乳样,检测免疫相关因子和牛奶品质等指标,分析不同饲养模式对奶牛健康和牛奶品质的影响。结果表明,集约化模式（CF型）的牛奶产量高于不完全集约化模式（IF型）的奶牛,IF型高于粗放饲养模式（EF型）（P〉0．05）;CF型奶牛的乳蛋白率高于IF型和EF型（P〈O．05）,EF型乳脂率高于CF型和IF型（P〈0．05）,EF型牛奶的体细胞数（scc）显著高于cF型和IF型（p〈0．（15）。EF型奶牛血液相关免疫指标IgA、IgG、TNF-d、IL-1p和IL-6等均显著高于CF型和IF型（P〈（0.05）。可以得出,EF型奶牛的牛奶产量、牛奶品质和健康状况均低于CF型和IF型。     

The Postpartum Reproductive Status of Dairy Cows in Two Areas in Iceland*

The paper describes the postpartum (pp) reproductive performance of 252 dairy cows in 2 areas in Iceland, in the north (Eyjafjörður) and in the south (Skeið), during a 12 months period.First pp ovulation occurred significantly earlier in primiparous cows, in cows in Skeið and in cows that calved in September—November.The average time of first pp artificial insemination (ai) was 72 days in both areas. Conception rate to first ai in these cows was 58 % in Eyjafjörður and 53 % in Skeið and the number of ai per conception was 1.6 and 1.8, respectively. In Eyjafjörður, 23 % of the cows were inseminated at the time of first pp ovulation. Sixtytwo percent of these cows conceived. In Skeið, 20 cows were inseminated at the time of first pp ovulation, and 9 or 45 % of these cows conceived. The interval from calving to conception was, on the average, 92 days in Eyjafjörður and 100 days in Skeið.Comparison of results from individual farms showed increase in number of conceptions to first pp ai (35–72 %) and decrease in number of services per conception (2.0–1.3) with increased mean number of days from calving to first ai (62–82 days).     

奶牛热应激综合征研究现状

奶牛热应激综合征是指奶牛受到超过本身体温调节能力的过高温度刺激时,作用于垂体-肾上腺皮质系统所引起机体的非特异性防御反应和特异性障碍的全身性适应症。热应激可导致奶牛的新陈代谢发生紊乱,奶牛生产性能下降,免疫力减弱,乳成分改变等,容易感染疾病,严重的热应激可导致奶牛中暑,甚至死亡。长期以来,奶牛热应激综合征一直影响着奶牛业的发展,给奶牛业带来很大损失。国内外专家很早就开始研究热应激对奶牛的影响,并取得了大量的研究成果。1奶牛的生物学特性奶牛起源于欧洲牛种(Bos tau-rus),具有耐寒怕热的体质结构,适合于较寒冷的地方…     

两种复合预混料对热应激奶牛产奶性能的影响

试验目的是观测两种不同配方的复合预混料在热应激条件下对中国荷斯坦奶牛产奶性能的影响。试验分为两组,每组7头,分别饲喂对照组(普通型预混料)和试验组(含抗热应激预混料)日粮,两种日粮基础配方相同,含预混料不同,平均温湿度指数(THI)为80.18±5.43。经32d的饲养试验表明:1、抗热应激功能型预混料较普通型预混料显著提高产奶量9%(P<0.05);2、两组间平均乳脂率、乳蛋白率、乳糖和非脂乳固体(SNF)无显著差异(P>0.05);3、试验期间平均产奶量与THI呈双曲线负相关关系(对照组Rc2=0.5365;试验组RT2=0.4894)(P>0.05)。     

赛乐硒对发情奶牛外周血生殖激素含量和繁殖性能的影响

选用35头处于干奶期40d、泌乳期相近和上胎平均日产奶量20kg的荷斯坦奶牛,采用完全随机区组设计分为7组,即:对照组,基础日粮(不加硒);试验组1、2、3添加亚硒酸钠,分别在基础日粮中加硒7.5mg/d、15mg/d和22.5mg/d;试验组4、5、6添加赛乐硒,分别在基础日粮中加硒7.5mg/d、15mg/d和22.5mg/d,研究赛乐硒和无机硒对奶牛发情周期生殖激素分泌和繁殖性能的影响。结果表明:赛乐硒较无机硒显著提高了发情周期促性腺激素释放激素、促卵泡素、促黄体素、雌二醇和孕酮含量,显著提高了受配率和受胎率,缩短了胎衣排出周期,促进母牛正常发情。适宜补硒量为15 mg/d。     

赛乐硒对发情奶牛外周血生殖激素含量和繁殖性能的影响

选用35头处于干奶期40d、泌乳期相近和上胎平均日产奶量20kg的荷斯坦奶牛,采用完全随机区组设计分为7组,即:对照组,基础日粮(不加硒);试验组1、2、3添加亚硒酸钠,分别在基础日粮中加硒7.5mg/d、15mg/d和22.5mg/d;试验组4、5、6添加赛乐硒,分别在基础日粮中加硒7.5mg/d、15mg/d和22.5mg/d,研究赛乐硒和无机硒对奶牛发情周期生殖激素分泌和繁殖性能的影响.结果表明:赛乐硒较无机硒显著提高了发情周期促性腺激素释放激素、促卵泡素、促黄体素、雌二醇和孕酮含量,显著提高了受配率和受胎率,缩短了胎衣排出周期,促进母牛正常发情.适宜补硒量为15 mg/d.     

棉酚对奶牛繁殖性能的影响研究

棉酚是一种存在于棉族植物的棉籽、根、茎杆色素腺里的黄色有毒多酚物质,是棉族植物抵御害虫的保护剂,但是棉籽产品用作动物饲料时,长时间或超剂量使用棉酚就会导致中毒,尤其是损坏动物的繁殖性能,本文综述了棉酚对奶牛繁殖性能的影响以及部分试验报道的安全剂量,以亟为合理配制饲料提供理论依据。     

麦可食酵母在热应激条件下对高产奶牛泌乳性能的影响

酵母和酵母培养物常用作调控反刍动物瘤胃发酵的饲料添加剂,其增奶效应在2~3磅/d之间,且多数试验结果在统计上差异不显著,有试验表明在炎热气候下,它能够增加产奶量,改善奶牛繁殖性能。为此,我们进行了在热应激条件下给泌乳早期奶牛饲喂酵母培养物的试验。1材料和方法1.1供试牛     

棉酚对奶牛繁殖性能的影响研究

棉酚是一种存在于棉族植物的棉籽、根、茎杆色素腺里的黄色有毒多酚物质,是棉族植物抵御害虫的保护剂,但是棉籽产品用作动物饲料时,长时间或超剂量使用棉酚就会导致中毒,尤其是损坏动物的繁殖性能,本文综述了棉酚对奶牛繁殖性能的影响以及部分试验报道的安全剂量,以亟为合理配制饲料提供理论依据。     

植物甾醇对奶牛生产性能、血液胆固醇和抗氧化能力的影响

本研究旨在探讨植物甾醇对奶牛产奶性能、血液胆固醇和抗氧化能力的影响,并探索植物甾醇在奶牛应用上的可行性。试验选择33头奶牛,随机分为3组,每组11头。对照组饲喂奶牛场常规日粮(添加0mg/d植物甾醇),试验Ⅰ、Ⅱ组分别饲喂额外添加200mg/d、800mg/d植物甾醇的日粮。结果表明:(1)试验Ⅰ组的产奶量相比对照组高了1.71kg/d,差异显著(P<0.05),但试验Ⅱ组与对照组差异不显著。(2)试验Ⅰ组TC含量低于对照组(第10天,P<0.01;第30、50天,P<0.05),试验Ⅱ组仅在第10天极显著低于对照组(P<0.01)。试验Ⅰ组HDL-C含量在第30天时极显著低于对照组(P<0.01),试验Ⅱ组的HDL-C含量第50天时显著低于对照组(P<0.05)。试验Ⅰ组LDL-C含量在第10天(P<0.05)、30天(P<0.05)和50天(P<0.01)均显著低于对照组,试验Ⅱ组只有在第10天时显著低于对照组(P<0.01)。试验组NEFA含量在第10、50天时均高于对照组,且差异极显著(P<0.01)。试验Ⅱ组E2含量显著低于对照组(P<0.05)。(3)在第10天时,试验Ⅱ组GOT含量显著高于对照组(P<0.05);试验Ⅱ组SOD含量在第10天(P<0.01)、30天(P<0.01)、第50天(P<0.05)显著高于对照组;试验Ⅰ组的GSH-Px在第30、50天均显著高于对照组(P<0.05);试验Ⅱ组的GSH-Px在第30天时高于对照组,差异极显著(P<0.01);试验Ⅰ、Ⅱ组的LPL含量在第50天时均极显著低于对照组(P<0.01);试验Ⅰ、Ⅱ组的HL含量在第10天(P<0.01)和第50天(P<0.05)均低于对照组。结果说明,日粮中添加200mg植物甾醇可提高奶牛产奶量,降低血液胆固醇水平,并起到抗氧化剂的作用,可维持奶牛的健康。     

Improved Detection of Reproductive Status in Dairy Cows Using Milk Progesterone Measurements

This study tested a model for predicting reproductive status from in-line milk progesterone `measurements. The model is that of Friggens and Chagunda [Theriogenology 64 (2005) 155]. Milk progesterone measurements (n = 55 036) representing 578 lactations from 380 cows were used to test the model. Two types of known oestrus were identified: (1) confirmed oestrus (at which insemination resulted in a confirmed pregnancy, n = 121) and (2) ratified oestrus (where the shape of the progesterone profile matched that of the average progesterone profile of a confirmed oestrus, n = 679). The model detected 99.2% of the confirmed oestruses. This included a number of cases (n = 16) where the smoothed progesterone did not decrease below 4 ng/ml. These cows had significantly greater concentrations of progesterone, both minimum and average, suggesting that between cow variation exists in the absolute level of the progesterone profile. Using ratified oestruses, model sensitivity was 93.3% and specificity was 93.7% for detection of oestrus. Examination of false positives showed that they were largely associated with low concentrations of progesterone, fluctuating around the 4 ng/ml threshold. The distribution of time from insemination until the model detected pregnancy failure had a median of 22 days post-insemination. In this test, the model was run using limited inputs, the potential benefits of including additional non-progesterone information were not evaluated. Despite this, the model performed at least as well as other oestrus detection systems.     

牛奶尿素氮含量与奶牛繁殖性能的关系

牛奶尿素氮(MUN)含量可能与奶牛繁殖性能有联系.本文初步探讨了用MUN含量评价奶牛繁殖性能的机理,综述了国内外关于MUN含量与奶牛繁殖性能关系的研究.