PDF(Pubmed)
Abstract：
The objective of this study was to evaluate the use of corpus luteum (CL) color Doppler (CD) ultrasonography and pregnancy-associated glycoproteins (PAG) for early pregnancy diagnosis and examine their ability to predict late embryonic/early fetal mortality (LEM) in Bos taurus beef replacement heifers. Beef heifers (n = 178) were exposed to a 7-d CO-Synch + CIDR protocol followed by fixed-time artificial insemination (day 0). On days 20 and 22, B-mode and CD ultrasonography were performed to evaluate CL morphometries and blood perfusion, respectively. Heifers were considered nonpregnant when CL area was <2 cm2 or estimated luteal blood perfusion was ≤30% of the total luteal area. Blood samples were collected on days 25 and 29 to estimate circulating concentrations of PAG. Conventional ultrasonography on days 29 and 94 was utilized to determine pregnancy status and considered the gold standard method for pregnancy diagnosis. Pregnant heifers had greater (P < 0.01) CL diameter, area, volume, and blood perfusion when compared with nonpregnant heifers on days 20 and 22. Accuracy of CD on days 20 and 22, and PAG on days 25 and 29 were 91%, 94%, 96%, and 98%, respectively. No false-negative results were observed for CD on both days 20 and 22 (negative predicted value = 100%) and false-positive results represented 8% and 6% of the diagnoses. Heifers that experienced LEM between days 29 and 94 of gestation had decreased luteal (P = 0.02) volume on day 20 and tended (P = 0.07) to have decreased concentrations of PAG on day 29 compared with heifers that maintained pregnancy. However, both CD and PAG failed to predict embryonic mortality. In conclusion, CD successfully detected most nonpregnant replacement heifers as early as day 20 of gestation, while resulting in no false negative diagnoses. Both CD and PAG failed to predict LEM in the present study.
Identifying nonpregnant females early after breeding allows cattle producers to rapidly rebreed females that failed to conceive after their first artificial insemination and consequently increases reproductive efficiency. Additionally, embryonic and fetal mortality during early gestation are the main drivers of pregnancy failure and represents a significant economic burden to both the beef and dairy industries. This study evaluated the use of color Doppler (CD) ultrasonography of specific ovarian structures and blood concentrations of pregnancy-associated glycoproteins (PAG) as potential methods to diagnose pregnancy earlier than industry-standard techniques. Moreover, the present study investigated the use of CD and blood PAG as predictor of pregnancy loss. Data generated here indicates that CD and blood PAG can accurately detect pregnancy as early as 20 and 25 d after insemination, respectively. In the present study, heifers that experienced pregnancy loss between days 29 and 94 of gestation tended to have decreased plasma concentrations of PAG during early pregnancy. Heifers experiencing pregnancy loss between days 29 and 94 of gestation were also more likely to have a luteal cavity on day 20 of gestation and had decreased luteal volume on the same day. However, results reported herein indicate that both CD and blood concentrations of PAG failed to predict pregnancy loss in replacement heifers.
Identifying nonpregnant females early after breeding allows cattle producers to rapidly rebreed females that failed to conceive after their first artificial insemination and consequently increases reproductive efficiency. Additionally, embryonic and fetal mortality during early gestation are the main drivers of pregnancy failure and represents a significant economic burden to both the beef and dairy industries. This study evaluated the use of color Doppler (CD) ultrasonography of specific ovarian structures and blood concentrations of pregnancy-associated glycoproteins (PAG) as potential methods to diagnose pregnancy earlier than industry-standard techniques. Moreover, the present study investigated the use of CD and blood PAG as predictor of pregnancy loss. Data generated here indicates that CD and blood PAG can accurately detect pregnancy as early as 20 and 25 d after insemination, respectively. In the present study, heifers that experienced pregnancy loss between days 29 and 94 of gestation tended to have decreased plasma concentrations of PAG during early pregnancy. Heifers experiencing pregnancy loss between days 29 and 94 of gestation were also more likely to have a luteal cavity on day 20 of gestation and had decreased luteal volume on the same day. However, results reported herein indicate that both CD and blood concentrations of PAG failed to predict pregnancy loss in replacement heifers.
摘要：
这项研究的目的是评估黄体（CL）彩色多普勒（CD）超声检查和妊娠相关糖蛋白（PAG）在早期妊娠诊断中的应用，并检查其预测Bostaurus牛肉替代母牛晚期胚胎/早期胎儿死亡率（LEM）的能力。将小母牛（n=178）暴露于7天CO-SynchCIDR方案，然后进行固定时间的人工授精（第0天）。在第20天和第22天，进行B型和CD超声检查以评估CL形态和血液灌注，分别。当CL面积<2cm2或估计的黄体血液灌注≤总黄体面积的30％时，小母牛被认为未怀孕。在第25天和第29天收集血样以估计PAG的循环浓度。第29天和第94天的常规超声检查用于确定妊娠状态，并被认为是妊娠诊断的金标准方法。妊娠母牛的CL直径较大（P<0.01），area,volume,与第20天和第22天的未怀孕母牛相比，血液灌注。第20天和第22天的CD和第25天和第29天的PAG的准确性为91％，94%,96%,98%,分别。在第20天和第22天均未观察到CD的假阴性结果（阴性预测值=100％），假阳性结果占诊断的8％和6％。与维持妊娠的小母牛相比，在妊娠的第29天至第94天经历LEM的小母牛在第20天的黄体体积减少（P=0.02），并且在第29天的PAG浓度趋于降低（P=0.07）。然而,CD和PAG均无法预测胚胎死亡率.总之,早在妊娠第20天，CD就成功检测到大多数未怀孕的替代母牛，而不会导致假阴性诊断。在本研究中，CD和PAG均未能预测LEM。
在繁殖后尽早识别未怀孕的雌性，可以使牛生产者迅速繁殖在第一次人工授精后未能怀孕的雌性，从而提高繁殖效率。此外,早期妊娠期间的胚胎和胎儿死亡率是妊娠失败的主要驱动因素，对牛肉和乳制品行业来说都是巨大的经济负担。这项研究评估了使用彩色多普勒（CD）超声检查特定的卵巢结构和妊娠相关糖蛋白（PAG）的血液浓度作为比行业标准技术更早诊断妊娠的潜在方法。此外，本研究调查了使用CD和血液PAG作为妊娠丢失的预测因子。此处生成的数据表明，CD和血液PAG早在授精后20和25d就可以准确检测到妊娠，分别。在本研究中,在妊娠的第29天至第94天之间经历妊娠损失的母牛在妊娠早期血浆PAG浓度趋于降低。在妊娠的第29天和第94天之间经历妊娠损失的母牛也更有可能在妊娠的第20天有黄体腔，并且在同一天黄体体积减少。然而,本文报道的结果表明，CD和PAG的血液浓度均无法预测替代母牛的妊娠损失。
在繁殖后尽早识别未怀孕的雌性，可以使牛生产者迅速繁殖在第一次人工授精后未能怀孕的雌性，从而提高繁殖效率。此外,早期妊娠期间的胚胎和胎儿死亡率是妊娠失败的主要驱动因素，对牛肉和乳制品行业来说都是巨大的经济负担。这项研究评估了使用彩色多普勒（CD）超声检查特定的卵巢结构和妊娠相关糖蛋白（PAG）的血液浓度作为比行业标准技术更早诊断妊娠的潜在方法。此外，本研究调查了使用CD和血液PAG作为妊娠丢失的预测因子。此处生成的数据表明，CD和血液PAG早在授精后20和25d就可以准确检测到妊娠，分别。在本研究中,在妊娠的第29天至第94天之间经历妊娠损失的母牛在妊娠早期血浆PAG浓度趋于降低。在妊娠的第29天和第94天之间经历妊娠损失的母牛也更有可能在妊娠的第20天有黄体腔，并且在同一天黄体体积减少。然而,本文报道的结果表明，CD和PAG的血液浓度均无法预测替代母牛的妊娠损失。
