Which of the following is used to help determine pregnancy in an animal?

Ultrasound is a valuable tool for determining pregnancy in animals. It uses high-frequency sound waves to create images of the internal structures, allowing veterinary professionals to visualize the developing embryos or fetuses within the uterus. This imaging technique can provide information on the number of fetuses, their health, and gestational age, making it a reliable method for confirming pregnancy.

While a blood test can also be used to detect pregnancy by measuring specific hormonal changes, ultrasound offers a direct visualization that provides additional information. X-rays are typically not used in the early stages of pregnancy due to potential risks to developing embryos, and a physical examination may not always provide enough detail to confirm pregnancy definitively. Therefore, ultrasound stands out as the most effective method for accurately assessing pregnancy in animals.