A new novel dark box can cause stress (Lay et al., 1992). Preliminary experiments with cattle are yielding a similar result (Kinsman, 1986, personal communication).13 Pregnancy Testing Methods Rectal Palpation - gloved hand is inserted into the rectum to palpate the uterus through the rectum wall Rectal Doppler Technique - probe that is inserted into the rectum.Bulls and cows go through a ritual before the actual “high-mount” of mating A cow’s gestation is approximately 246 days, + or – 10 days Artificial insemination is common, with a success rate of 50% – 80%.