二级竞争酶联免疫孕酮临界点判别分析在乳牛早期妊娠诊断上的应用

本文根据二级竞争酶联免疫定量测定的原理建立了用于乳牛早期妊娠诊断的二级竞争酶联免疫孕酮临界点判别分析法．本方法无需仪器比色和数学计算，反应结果清晰可辨、操作简便．根据对５２０头次配种后２１ｄ乳牛进行测试，其总正确率为８３．８％，其中阴性正确率为９０％，阳性正确率为７９％。     

Uterine biology in pigs and sheep

ABSTRACT: There is a dialogue between the developing conceptus (embryo-fetus and associated placental membranes) and maternal uterus which must be established during the peri-implantation period for pregnancy recognition signaling, implantation, regulation of gene expression by uterine epithelial and stromal cells, placentation and exchange of nutrients and gases. The uterus provide a microenvironment in which molecules secreted by uterine epithelia or transported into the uterine lumen represent histotroph required for growth and development of the conceptus and receptivity of the uterus to implantation. Pregnancy recognition signaling mechanisms sustain the functional lifespan of the corpora lutea (CL) which produce progesterone, the hormone of pregnancy essential for uterine functions that support implantation and placentation required for a successful outcome of pregnancy. It is within the peri-implantation period that most embryonic deaths occur due to deficiencies attributed to uterine functions or failure of the conceptus to develop appropriately, signal pregnancy recognition and/or undergo implantation and placentation. With proper placentation, the fetal fluids and fetal membranes each have unique functions to ensure hematotrophic and histotrophic nutrition in support of growth and development of the fetus. The endocrine status of the pregnant female and her nutritional status are critical for successful establishment and maintenance of pregnancy. This review addresses the complexity of key mechanisms that are characteristic of successful reproduction in sheep and pigs and gaps in knowledge that must be the subject of research in order to enhance fertility and reproductive health of livestock species.     

Analyses of parental and seasonal influences on the synchrony of dexamethasone-induced lambing and lamb characteristics

Synchronization of parturition in a commercial flock of sheep has many advantages including the maintenance of the efficiency of the operation as well as optimization of care for periparturient animals. In a research setting, using an ovine model for experiments involving the induction of parturition yields the results that can be applied to other mammalian species. In sheep, as well as in a variety of other farmed species, dexamethasone is the drug used to induce synchronized parturition at the end of gestation. However, considerable variations have been noticed in the time between induction and the onset of lambing. This study set out to determine the role that the breed of dam and sire, the age and reproductive history of ewes, the month of induction and the litter/lamb characteristics played in determining the time between dexamethasone treatment and parturition. The lambing was induced in 146 ewes (4 purebred Dorset, 19 purebred Rideau Arcott and 123 Rideau Arcott × Dorset ewes) using a single i.m. dose of 20 mg dexamethasone (Unidex^®, Univet Pharmaceuticals, Milton, ON, Canada) on day 140 of gestation. The ewe breed was weakly correlated (r = − 0.19, P < 0.05) whereas the sire breed was moderately correlated (r = − 0.37, P < 0.001) to the time between dexamethasone treatment and the onset of parturition (the breed in this study was defined as the % of the Rideau Arcott genotype). The time between induction and the onset of labour averaged 57.3 ± 5.3 h and 64.3 ± 8.2 h in February and April, respectively, and it was significantly longer (P < 0.05) compared with the times recorded in July, September and November (42.0 ± 2.0 h, 38.7 ± 2.8 h and 36.1 ± 5.0 h, respectively). There was a negative correlation (r = − 0.41, P < 0.001) between the proportion of ram lambs and the mean birth weight of ewe lambs. These results can be interpreted to suggest that the breed and time of the year may both affect the synchrony of dexamethasone-induced lambing. The reasons for the associations found between the month of induction and the time elapsed to the onset of parturition as well as between the proportion of ram lambs and birth weights of ewe lambs are not fully understood and warrant further studies.     

高寒地区奶牛“性控精液”应用推广试验

试验对奶牛＂性控精液＂在高寒地区的推广应用进行了研究。结果表明：成年牛的受胎率（41.64%）极显著低于青年牛（65.31%）（P〈0.01）;性控精液与常规精液相比其受胎率,青年牛组分别为65.31%和67.80%,两者之间差异不显著（P﹥0.05）,而成母牛组分别为41.64%和54.03%,两者之间差异极显著（P﹤0.01）;饲养状态（集中饲养、散养）对性控精液的受胎率有显著影响（P〈0.05）,集中饲养明显优于散养;季节对性控精液的受胎率无显著影响（P〉0.05）。     

体外授精-胚胎移植妊娠率与HCG注射日卵泡大小的相关性

目的：探讨体外受精一胚胎移植（in vitro fertilization and embryo transfer,IVF—ET）的COS周期中人绒毛膜促性腺激素（HCG）给予日卵泡大小与妊娠率的相关性。方法：将414个IVF／ICSI-ET周期中HCG日最大卵泡径线大小分为A组（〈16．0mm）、B组（16．5～17．5mm）、C组（18．0～19．0mm）、D组（≥19．5mm）,分析其妊娠结局、获卵数、子宫内膜厚度与可利用胚胎数。结果：各组妊娠率分别为：A组17．8％,B组30．1％,C组34．6％,D组20．5％,差异有统计学意义（P〈0．05）,获卵数差异亦有统计学意义（P〈0．05）,子宫内膜厚度比较无统计学差异。结论：体外授精-胚胎移植COS周期中,主导卵泡在16．5～19．0mm时决定给予HCG妊娠率较高。     

不同繁殖类型的牦母牛在发情期和围产期的体况评分

对高原型牦母牛在发情期和围产期进行体况评分测定,结果发现发情牦母牛体况评分为4.16,不发情牦母牛体况评分为3.39,其中发情牦母牛中一年一胎牦母牛(藏语青麻)、两年一胎牦母牛(藏语牙日麻)和两年以上未产的牦母牛(藏语干巴)的体况评分分别为4.37、4.08和4.18。在围产期青麻牛的体况评分最低,为2.06,怀孕牙日玛和未怀孕牙日玛的体况差异不大,分别为2.25和2.33。干巴牦母牛在冷季的体况评分最高,为2.58。暖季和冷季对青年牦母牛的体况评定结果表明,发情青年牦母牛的体况评分为3.75,未发情青年牦母牛为3.53;在冷季,青年牦母牛的体况评分为2.54。