title: Studies on pregnancy diagnosis in domestic animals by an ultrasonic Doppler method. I. Pregnancy diagnosis in the pig and fetal heart rate changes during pregnancy.
mesh_terms: D000818:Animals; D005260:Female; D005318:Fetal Heart / Q000502:physiology*; D006339:Heart Rate; D011247:Pregnancy; D011258:Pregnancy Tests / Q000662:veterinary*; D011270:Pregnancy, Animal; D013552:Swine / Q000502:physiology*; D014465:Ultrasonics / Q000662:veterinary*; D014463:Ultrasonography