[Early detection of pregnancy of the rat]

A manual palpation method has been devised for early detection of pregnancy of the rat. One hand gently restrains the animal by holding it from behind in the usual manner. The thumb of the other hand is placed on the posterior abdomen and the first three fingers on the ventral midline. The three fingers were pressed gently upward and laterally. The embryos can then be palpated through the abdominal wall between the thumb and the three fingers. The number of fetuses was not affected by this palpation method. Using this technique, pregnancy was detected on the 5th day of gestation with an accuracy rate of 80% and between the 6th and 9th days with a 100% accuracy.