the baby and its heart beat can be detected relatively easily with trans-abdominal and trans-vaginal examination.This is presuming that the pregnancy is actually at this stage of development.When this is seen, the outcome for this pregnancy to continue on normally is good; with a probability of more than 95%.Miscarriage in the form of a "blighted ovum" or "missed abortion" can be diagnosed easily when an empty gestational sac is seen after 7-8 weeks of pregnancy or when the fetal heart movement is absent.
Fetal heart movements can be seen as early as 6 weeks of gestation, with the trans-vaginal transducer.
However, even if oestrus detection is good, not all of these cows will be pregnant.
On the other hand, up to 7% of pregnant cows will show some signs of oestrus during pregnancy.
Accuracy: depends on the experience of the practitioner and can reach 95%.
Rectal examination is usually carried done between 35 and 65 days post AI.