犊牛断乳对产后母牦牛发情周期恢复的影响

对150头当年产母牦牛在发情季节进行犊牛断乳,同时对166头隔年产干乳母牦牛进行对照,观察了犊牛断乳后母牦牛发情周期恢复的规律。结果表明断乳组母牦牛发情率为69.33%,发情持续期为15d;隔年产母牦牛发情率为89.94%,发情持续期为62d。     

补饲与犊牛断乳对产后母牦牛发情周期恢复的影响研究

为了提高当年产犊母牦牛的发情率,我们对选定的120头怀孕母牦牛进行补饲,同时在犊牛产后3个月对犊牛进行隔离断奶,补饲试验于2010年3月初开始：100头母牦牛随机分为两组,试验组Ⅰ 50头母牦牛隔离断奶后进行同期发情和定时授精处理;Ⅱ组50头母牦牛隔离断乳.不进行同期发情处理,发情母牛进行人工授精。人工授精冻精液为荷斯坦和野牦牛冻精。配种45d后进行怀孕诊断。Ⅰ组发情39头,发情率为78%（39/50）,怀孕34头妊娠率为68%（34/50）;Ⅱ组发情31头,发情率为62%（31/50）,怀孕27头,妊娠率为54%（27/50）。相同草场放牧50头适配母牦牛作为对照。对照组母牛和犊牛不进行隔离和短期断乳;对照组发情率为12%（6/50）,妊娠率为6.32%（3/50）。试验结果表明,通过对带犊的母牦牛实施隔离断奶,能够明显提高当年产犊母牦牛的发情率和妊娠率。     

牦牛犊牛早期断乳的研究

对28头牦牛犊牛在3月龄是断乳，与5月龄断乳的相比较，结果实验组犊牛断乳体重是42．96kg，增重20．18kg，增重率为46．97％。对照组犊牛断乳体重是66．61kg，增重30．31kg，增重率为45．50％。实验组比对照组高1．47％，差异性不显著（P〉0．05）。19月后，试验组犊牛体重是66．78kg，增重23．91k．增重率是35．76％。对照组犊牛体重是106．45kg，增重39．48％，增重率是37．43％。试验组比对照组低1．67％，差异性不显著（P〉0．05）。在2008年试验组母牦牛的繁殖数是59头，繁殖率是92．19％。对照组的繁殖数是57头，繁殖率是89．09％。试验组的繁殖数比对照组多2头，试验组比对照组高3．13％，差异性不显著（P〉0．05）。犊牛的生长发育和母牛的繁殖率上没有受到影响。证明对3月龄的牦牛犊牛可以进行断乳。     

不同时间断乳对母牦牛发情影响的观察

对带犊牦牛分别在8月1日、8月27日和10月12日进行断乳,结果Ⅰ组母牛共发情104头,发情率为69.33%,Ⅱ组母牛发情54头,发情率为36.00%,Ⅰ组比Ⅱ组多发情50头,高48.01%,差异性极显著(P<0.01)。Ⅲ组母牛发情4头,发情率4%。Ⅱ组比三组Ⅲ组多发情36头,高90%,差异性极显著(P<0.01)。Ⅰ组母牦牛发情率最高,持续时间长,Ⅱ组母牦牛只有一个发情高峰,持续比较短,Ⅲ组母牦牛发情率低,持续时间也短。     

牦牛发情周期黄体组织结构的观察

选用48头成年母牦牛，采用光镜和电镜技术对发情周期中不同时期黄体的组织结构进行了观察。结果表明，牦牛黄体主要由2种细胞组成，即颗粒黄体细胞（granulasa lutein cell，GLC）和膜黄体细胞（theca lutein cell，TLC），其特征性变化主要表现在GLC和纤维的分布。成熟黄体中GLC及其胞核的平均直径分别为36．6μm和15．2μm，而TLC则分别为14．4μm和10．9μm。黄体细胞胞质中线粒体的比例随黄体的成熟而增高；脂滴在Ⅰ期黄体时较多，Ⅱ期时减少，Ⅲ期时显著增多，后又减少；滑面内质网也随黄体的成熟而增加，并随黄体的退化发生膨胀。黄体组织中有同心圆状或同心轮状的粗面内质网膜系统。黄体细胞间主要是缝隙连接，偶见中间连接。黄体组织中存在窗孔型毛细血管．     

断乳后对母牦牛注射氯前列烯醇钠观察其发情效果

断乳后对母牦牛注射氯前列烯醇钠促发情处理,第一次药物处理后,两组母牛发情头数均为0头,第二次药物处理后,试验组母牦牛发情15头,发情率为75%。对照组母牦牛发情8头,发情率为40%。实验组母牦牛比对照组多发情7头,高46.67%,差异性极显著(P<0.01)。     

牦牛发情周期子宫组织结构的观察

采用组织学和形态计量学的方法对发情周期牦牛子宫的组织结构及形态变化进行了观察。结果表明,牦牛子宫壁具有3层结构,分别为黏膜(子宫内膜)、肌层(子宫肌层)和浆膜(子宫外膜)。子宫内膜表面上皮和腺上皮在卵泡期为单层柱状上皮,在黄体期上皮高度明显增加,为假复层柱状上皮。表面上皮主要由分泌细胞及少量淋巴细胞组成。分泌细胞可分为亮细胞和暗细胞2种。亮细胞呈柱状,细胞体积较大,胞质弱嗜酸性;暗细胞呈两侧压扁的细条状,胞质强嗜酸性。腺上皮的细胞组成与表面上皮相似。PAS反应可见黄体期子宫内膜表面上皮、腺上皮和基质中阳性分泌颗粒较卵泡期的多。卵泡期固有层内偶见嵌套腺管、扩张腺管和弥散淋巴组织,但黄体期固有层内仅偶见嵌套腺管。此外,与卵泡期相比,黄体期子宫内膜和子宫肌层的厚度显著增加(P0.01)。黄体期子宫内膜腺管的平均直径、单个腺管的面积和周长、每平方毫米内腺管的总面积和总周长都较卵泡期的大,差异极显著(P0.01),而每平方毫米内腺管的数量差异并不显著(P0.05)。可见,牦牛子宫的组织结构在发情周期发生着有规律的变化。     

牦牛发情周期中卵巢卵泡发育状况的组织学观察

运用组织学技术对36头处于发情周期的健康成年母牦牛卵巢卵泡的结构与发育状况进行了观察。结果表明，牦牛发情周期中卵巢卵泡发育的组织结构与其他牛基本相似。每对卵巢中原始卵泡数和生长卵泡数在发情前期、发情期、发情后期和发情间期之间差异不显著（P〉0．05）；发情前期的囊状卵泡数与发情期、发情后期和发情间期之间差异不显著（P〉0．05），发情期和发情后期均与发情间期差异显著（P〈0．05）。闭锁生长卵泡数在4个时期之间差异不显著（P〉0．05）；发情期的闭锁囊状卵泡数与其他3期之间差异极显著（P〈0．01），发情前期和发情间期均与发情后期差异显著（P〈0．05）。各级卵泡的闭锁形式各有特点。在生长卵泡、囊状卵泡及相应闭锁卵泡的卵泡膜中均见到了胶原纤维和网状纤维。     

GDF-8蛋白在牦牛发情周期输卵管的表达

生长分化因子8(Growth differentiation factor 8,GDF-8)在肌肉的分化和生长中有负调控作用,但其是否参与调节动物生殖活动证据仍然不足.为研究GDF-8蛋白在牦牛发情周期输卵管不同部位中的表达差异,从屠宰场采集卵泡期和黄体期牦牛输卵管峡部、伞部和壶腹部组织样品,进行了免疫组织化学染色和W...     

断乳牦牛犊的育肥试验及其生长发育情况的研究

[目的]为了探索在育肥条件下高寒牧区牦牛犊的生长发育情况,促使牦牛犊商品化,实施牦牛高效饲养技术与适时出栏技术相结合,改变本地区传统饲养模式,促进牦牛业向效益型畜牧业转变,为今后普及牦牛犊舍饲育肥,提供可靠数据和标准化饲养管理技术。[方法]于2012年12月~2013年5月,在贵南县开展了断乳牦牛犊舍饲育肥及生长发育效果观测试验。[结果]显示育肥牦牛犊的体高、体斜长、胸围、管围、体重分别达到了86.19cm、94.07cm、113.50cm、12.10cm、91.63kg与对照组相比差异均显著(P0.05)。[结论]对断乳牦牛犊进行舍饲育肥是牧区加快牦牛出栏、调整牛群结构、增加牧民收入的好方法。     

Body status and blood metabolites profiles during resumption of postpartum ovarian activity in yak (Poephagus grunniens)

We examined the changes in body weight (BW), back-fat thickness (BFT) and blood metabolites in relation to postpartum (PP) ovarian activity status in twenty female yaks raised under semi-intensive system. BFT and ovarian activities, like follicle development, ovulation (OV) and corpus luteum (CL) development, were monitored from 4 to 15 weeks (wk) PP using ultrasonography. Resumption of ovarian activity was confirmed with ovulation of dominant follicle (DF) and subsequent CL development, and >1 ng/ml progesterone concentration in blood plasma sample after 1week of ovulation. Yaks were further classified as cyclic (with CL), acyclic (without CL), and cystic (with >25 mm follicular cyst; FC). Within 20 weeks PP, 60% yaks resumed cyclic ovarian activity, while 25% failed to initiate cycling activity, and 15% developed follicular cysts. In all categories of yak, BW gradually decreased (p < .05) till nadir; however, nadir reached earlier (p < .05) in acyclic yaks. BFT differed (p < .05) among the yak groups, but it tended to be higher in cyclic yaks as compared to acyclic and cystic. No difference (p > .05) in non-esterified fatty acids (NEFA) values was found among the different categories of yaks, whereas, beta-hydroxy butyrate (BHB) levels were higher in cystic animals as compared to acyclic and cyclic. Blood glucose levels decreased in all yaks during initial 2 weeks after calving. Our findings suggest that yaks with low BW, BFT and glucose levels, and higher BHB values were at risk of delayed resumption of ovarian activity and concomitant development of follicular cysts.     

Postpartum oestrous cycling resumption of yak cows following different calf weaning strategies under range conditions

Early weaning can improve body condition and reproductive performance of cows. The objectives of this study were to examine and compare oestrous cycling resumption, behaviour and blood parameters of yak cows following four different strategies of calf weaning. Twenty‐six yak cows (4–8 years) and their calves (94.3 ± 2.4 days) were studied in which calves were: weaned naturally with free access to their mothers (NW; n = 13); weaned abruptly and separated permanently from their mothers (PW; n = 5); separated temporarily from their mothers for 15 days (TW; n = 5); and fitted with nose plates for 15 days, but allowed free access to their mothers (NP; n = 3). Yak cows with sucking calves (NW) spent more time grazing in the cold season (from d 39 to 84). Based on serum progesterone concentrations, none of nine NW yak cows resumed oestrous cycling during the study, while seven of nine yak cows with weaned calves resumed cycling (3/3 for PW; 2/3 for TW; and 2/3 for NP yaks). We concluded that early weaning improved postpartum reproductive performance of yak cows on the Qinghai‐Tibetan plateau and that abrupt and permanent weaning was an appropriate strategy.     

日粮组成对牦犊牛消化和能量代谢的影响

 在海拔３９８０ｍ 的果洛州大武乡对３头牦犊牛分别饲喂１００％的青贮披碱草（Ａ）、４０％精料＋６０％青贮披碱草（Ｂ）、６０％精料＋４０％青贮披碱草（Ｃ）３种不同日粮,按３×３ 拉丁方设计了消化代谢试验。结果表明,１）日粮干物质、有机质、粗蛋白和能量消化率差异显著（P＜０．０５）,粗灰分消化率差异不显著（P＞０．０５）,且随日粮中精料比例的增加,各营养成分的消化率逐渐降低;２）日粮Ｃ 的能量代谢率显著低于日粮Ａ 和日粮Ｂ（P＜０．０５）,但消化能转化为代谢能的效率差异不显著（P＞０．０５）,其平均转化效率为０．７８;３）粪和尿中排出钙差异显著（P＜０．０５）,粪中排出磷差异不显著（P＞０．０５）,而尿中排出磷差异显著（P＜０．０５）;钙存留量随日粮中精料比例的增加而减小,磷存留量在Ａ 日粮下最大。以上结果说明牦犊牛对日粮的消化和能量代谢与其组成密切相关,而且表观消化率随日粮水平的提高而降低,其能量转化率低于生长牦牛和成年牦牛。因此,该结果可为牦犊牛的补饲和快速育肥提供科学依据。     

不同犊牛培育方法对育成母牦牛生长发育的影响

采用不同犊牛培育方法,分别考察对传统饲养条件和高效繁育技术条件下对后代公犊牛及育成母牛生长发育的影响。研究结果表明:与传统对照组相比,犊牛培育组犊牛成活率达到97.23%,犊牛培育组的成活率、初选合格率、复选合格率和定选合格率分别为91.67%、80.56%和77.78%,分别比传统对照组提高12.90%、13.79%、11.54%和27.26%,差异显著(P<0.05)。犊牛体高、体斜长、胸围、管围及体重显著提高,差异显著(P<0.05)。采用犊牛培育技术,后代犊牛及育成牛生长发育各项指标较对照组明显增加,有效提高牦牛种母牛培育合格率,从而为建立优良种母牛核心群提供一条切实有效的生产途径。     

阴道涂片法确定绵羊情期的研究

实验用阴道涂片法确定绵羊发情时期。在发情季节,把经试情确定发情周期正常的母羊于发情前期、发情期、发情后期和发情间期分别进行阴道涂片,观察各种细胞成分及其变化。结果说明,绵羊阴道涂片中主要可见到白细胞、有核上皮细胞、角化上皮细胞和细胞碎片等4种细胞成分。白细胞在发情间期数目最多,显著(P<0.01)多于其它各期;各时期有核上皮细胞的数目无显著差异;角化上皮细胞在发情期数目最多,明显(P<0.01)高于其它各期;发情间期和前期的细胞碎片明显(P<0.01)多于发情期和发情后期。因此,有可能以角化上皮细胞和白细胞的数目作为指标,确定绵羊的发情时期。     

产后无发情和亚发情母牦牛激素诱导发情试验

选择怀孕母牦牛84头,在生产前后1个月进行补饲,其中40头在产后当年发情季节进行激素诱导发情试验,44头作对照;另选择60头自然生产的产后母牦牛在发情季节进行单纯的激素诱导发情试验,60头作对照.激素诱导发情方法是0 d注射氯前列烯醇0.2 mg,7 d后注射促黄体素释放激素A3 25 μg,连续3 d;在0和7 d进行直肠检查和血样采取,血样进行孕酮测定;测定处理时母牦牛卵巢状态,观察母牦牛发情配种受孕情况.结果显示,通过直肠检查和血浆孕酮测定,发现无发情状态的产后母牦牛占产后牦牛的63.33%和65%,亚发情的产后母牦牛占产后牦牛的36.67%和35%.采用氯前列烯醇和促性腺激素释放激素处理方案进行诱导发情,26.67%的产后母牦牛在处理后出现了发情;对怀孕母牦牛在围产期进行补饲,产后母牦牛在发情季节采用氯前列烯醇和促性腺激素释放激素诱导发情,有45.45%的产后母牦牛恢复了发情,而只补饲不进行激素诱导发情的母牦牛只有20%的母牦牛出现了发情;通过孕酮测定发现2组中激素诱导发情成功的母牦牛中,有68.18%和72%是处于亚发情状态的母牦牛.结果表明,氯前列烯醇和促性腺激素释放激素进行诱导发情的处理方案适合于产后亚发情状态的母牦牛.     

Predictors of beef calf temperament at weaning and its impact on temperament at breeding and reproductive performance

Two experiments were conducted to determine (i) factors influencing calf temperament at weaning, (ii) association between heifer–calf temperament at weaning and temperament at breeding and (iii) effect of heifer–calf temperament on pregnancy rate per artificial insemination (P/AI). In experiment 1, beef cows and their calves (n = 285) from three farms were used. Sire docility estimated progeny difference (EPD) score, birth type (normal or assisted), calf gender, calf behaviour (during 1st 4 weeks) and calf health status (until weaning) were recorded. Cows and calves were assigned a temperament score (0—calm; 1—excitable), and all cows were given a body condition score (BCS, 1–9; 1—emaciated; 9—obese) at weaning. Calf's illness (p < .05), low sire docility EPD score (p < .05), altered gait (p < .05), altered resting behaviour (p < .01), reduced/no play behaviour (p < .05) and cow excitable temperament (p < .001) increased calf excitable temperament at weaning. In experiment 2, replacement heifer–calves (n = 758) from 12 farms were assigned a temperament score at weaning and later at breeding. Blood from 40 calves at weaning and 31 heifers at initiation of synchronization (same animals) was collected by coccygeal venipuncture for determination of circulating cortisol and substance P concentrations. Heifers were assigned a BCS and reproductive tract score (RTS, 1–5; 1—immature, acyclic; 5—mature, cyclic), synchronized for fixed time AI, observed for oestrus and were artificially inseminated. Cortisol concentrations were increased in excitable heifer–calves compared to calm heifer–calves at weaning (p < .05), and substance P was increased in excitable compared to calm females both at weaning and breeding (p < .05). Low sire EPD docility score (p < .01), heifer–calf excitable temperament at weaning increased excitable temperament at breeding (p < .01). Controlling for BCS categories (p < .01), oestrous expression (p < .0001) and temperament at breeding by oestrous expression (p < .05), the calf's excitable temperament at weaning (p < .001) reduced P/AI (Calm, 62.7 (244/389) vs. Excitable, 53.4% (197/369); p < .01). In conclusion, selection of docile cows and sires with greater docility EPD score should be given consideration to reduce calf excitement. Temperament in beef female can be detected earlier in their life and could be used as a tool in the selection process and to improve their performances.     

绵羊发情周期中VEGF在卵巢中的表达

应用免疫组化方法结合计算机图像分析技术,分析同期发情后0、5、9、12、15d的绵羊卵巢中血管内皮生长因子（Vascular endothelial growth factor,VEGF）表达强度变化,以期了解VEGF在绵羊卵巢发情周期不同时期的表达规律。结果显示：VEGF阳性目标主要出现于卵泡膜与颗粒细胞。原始卵泡、初级卵泡、次级卵泡VEGF表达依次增强（P〈0．05）。发情周期0～5d,大窦腔卵泡（颗粒细胞4～8层）VEGF表达量骤然上升（P〈0．05）,而9d开始显著下降,与5d比较差异显著（P〈0．05）。12d继续下降（P〈0．05）且为最低值,15d又明显上升（P〈0．05）。VEGF在卵巢间质呈弱表达,各个时期之间差异不显著（P〉0．05）。结果表明,绵羊卵巢存在着血管周期性新生的变化特点,而VEGF在这种周期性血管新生过程中起着重要的调控作用。