Department of Animal Pathology, Section of Reproduction and Obstetrics, University of Santiago de Compostela, 27002 Lugo, Spain.
Anim Reprod Sci. 2011 May;125(1-4):13-9. doi: 10.1016/j.anireprosci.2011.02.022. Epub 2011 Feb 18.
Ultrasonography (US) provides detailed visualization of the fetus in early pregnancy in cows, thus allowing for fetal sex determination. The objective of this prospective observational study was to determine the feasibility and accuracy of a single US examination to diagnose fetal sex in dairy cattle under routine reproductive management conditions. For this purpose, 953 Holstein cows at 7-16 weeks of gestation were examined. Gender assignment was performed in 822 cows, while the genitalia could not be clearly visualized in 131 (13.7%) of the fetuses. After calving, it was verified that 99.3% of the diagnoses were accurate. Fetal sex was correctly determined by US in 99.5% of male fetuses and 98.8% of female fetuses. Fetal sex determination was less accurate when conducted before d 55 of gestation. Likewise, it was verified that fetal sex, cow age and ultrasonographic diagnosis section did not have a significant influence (P>0.05) on diagnostic accuracy. With respect to the plane used for diagnosis, the sagittal view was poorly used for early pregnancy diagnosis, whereas the longitudinal and cross-sectional planes were used most frequently. These results demonstrate that US can be routinely applied under farm conditions to accurately determine the fetal sex in cattle between days 51 and 111 of gestation without apparent influence of cow age, US scanning plane or fetal sex. Conversely, days of gestation affected the accuracy and feasibility of US gender determination, showing poorer results when the diagnosis was made before day 55 of gestation.
超声检查（US）可提供牛早期妊娠胎儿的详细图像，从而能够确定胎儿性别。本前瞻性观察研究的目的是确定在常规生殖管理条件下，单次 US 检查诊断奶牛胎儿性别的可行性和准确性。为此，对 953 头荷斯坦奶牛进行了 7-16 周龄的妊娠检查。在 822 头奶牛中进行了性别分配，而在 131 头（13.7%）胎儿中无法清晰显示生殖器。产后证实，99.3%的诊断是准确的。US 对 99.5%的雄性胎儿和 98.8%的雌性胎儿的性别诊断准确。在妊娠 55 天之前进行胎儿性别诊断的准确性较低。同样，还验证了胎儿性别、奶牛年龄和超声诊断节段对诊断准确性没有显著影响（P>0.05）。就用于诊断的平面而言，矢状面在早期妊娠诊断中的应用较差，而纵切面和横切面则最常使用。这些结果表明，US 可以在农场条件下常规应用，在妊娠 51-111 天期间准确确定牛的胎儿性别，而奶牛年龄、US 扫描平面或胎儿性别无明显影响。相反，妊娠天数影响了 US 性别判断的准确性和可行性，在妊娠 55 天之前进行诊断时结果较差。
