应用B型超声波鉴别马胎儿性别

通过胎儿尾部和脐带之间的生殖器结节定位进行马性别诊断，雄性胎儿准确率97．8％（182／186），雌性胎儿99．4％（160／161）。胎儿性别测定的最适时间为妊娠后59d和68d之间。妊娠中期胎儿性别诊断也非常可靠。超声波性别鉴定准确率达100％。在雄性，从100d到220d妊娠常规获得阴茎或包皮的图像；在雌性，从118d到227d妊娠马观察到胎儿乳腺和乳头。在马繁殖上常规使用的5MHz线性传感器，大多数情况下一直可用到妊娠160d。当胎位太高或其大小超过超声设备监测范围时，须使用3．5MHz探头。若掌握好性别鉴定的最适时间和认识正确的解剖结构，两种方法都是非常精确的。

Ultrasonographic Determination of Equine Fetal Gender

The method was used in the fetal gender diagnosis at auuracy rate of 978% (182/186) of males and 99.4% (160/161) of females when it could locate the genital tubercle between the tail and umbilical cord. The optimal days for fetal gender determination are between day 59 and day 68 of gestation. The method of mid gestation diagnosis of fetal gender is very reliable,too. There is 100% agreement in gender determination between the results obtained by ultrasonography and those obtained at birth. In males, the penis and/or the prepuce are routinely imaged from 100 days to 220 days gestation. In females, the mammary glands and teats are observed from 118 days to 227 days of gestation. The 5 MHz linear transducer, routinely used in equine reproduction, allows gender diagnosis up to 160 days gestation in most cases. When the fetus is located too high in the mare's abdomen or when its size exceeds the capacity of the ultrasound equipment, a 3.5 MHz probe has to be used. Both ultrasound techniques are very accurate, provided gender identification is made during the optimal window of time, with recognition of the correct anatomical structures.