Breed differences in biparietal diameters of second trimester Toggenbubrg, Nubian and Angora goat fetuses.

Seven purebred Toggenburg fetuses in four does, six purebred Nubian fetuses in four does, and eight Angora fetuses in six does were repeatedly measured using transabdominal real-time ultrasound with a 5 MH(z) linear-array transducer from 40 d to 100 d gestational age (GA) and their biparietal diameters (BPD) were determined. For Toggenburg goats the GA = 27.9 + 1.64 BPD; for Nubian goats the GA = 26.8 + 1.74 BPD; for Angora goats the GA = 28.6 + 1.77 BPD. The breed differences in GA for equal BPD are insignificant at the beginning of the second trimester but are +3 d for Nubian and +6 d for Angora fetuses by the end of the second trimester.