Ultrasonography is an excellent tool to detect pregnancy and estimate fetal gestational age.
Average length of gestation for cats is about 64 days (range from 52-74 days) 😺and foetus heart beat🫀 generally can be detected at around day 25-38. Counting the number of foetus can sometimes be difficult with ultrasound therefore radiograph🩻 should be performed at the same time. Viability of the foetus can be determined by the present of heart beat. There are few methods to determine the gestation age, and one of my favorite is to use head diameter.
–Medical tips–
⭕️Gestational age (GA) +/-2 days (>40 days gestation, measurements in cm)
GA = (25 x head diameter) + 3
⭕️Days before parturition (DBP)
DBP = (-2.1 x ( Head diameter in mm)) + 50.74
In this case
GA = (25 x 1.9) + 3 = 50.5
DBP = (-2.1 x 19) + 50.74 = 10.84
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And in this case, the queen gave birth naturally and successfully 10 days after examination.