Pregnancy diagnosis in the guinea pig.

A method for diagnosing pregnancy in the guinea pig by manual palpation was developed. Using this technique, pregnancy was detected between the 15th and 30th day of gestation with 98% accuracy. The 2% error consisted of animals that were pregnant but diagnosed as nonpregnant. Common mistakes that led to diagnosing nonpregnant animals as pregnant were: (1) palpation of fecal pellets; (2) palpation of left kidney; and (3) palpation of the sartorius muscle. Common errors that led to diagnosing pregnant animals as nonpregnant were: (1) failure to search the entire abdomen; (2) too close apposition of thumb and forefingers while searching the abdomen; and (3) failure to deprive animals of feed before palpation.