What is used to detect a fetus in a pregnant animal?

Ultrasound is the preferred method for detecting a fetus in a pregnant animal due to its ability to create real-time images of the developing fetus. It is non-invasive and does not expose the pregnant animal or the fetus to harmful radiation, making it safe for both. Ultrasound can provide vital information such as the number of fetuses, their positioning, and help assess any potential abnormalities or concerns during the pregnancy.

While X-rays can be used later in pregnancy to visualize the skeleton of the fetus, they pose a risk due to radiation exposure, making them less ideal for early detection. Blood tests may provide indications of pregnancy but do not directly visualize the fetus. Physical examinations can offer clues about pregnancy but typically cannot confirm fetal presence effectively without additional diagnostic methods like ultrasound. Thus, ultrasound stands out as the most effective and safest technique for detecting a fetus in pregnant animals.