Pregnancy Diagnosis and Fetal Age Estimation Using Ultrasonography in Goats

Abstract

Managing reproduction in dairy goat herds depends heavily on timely pregnancy diagnosis and accurate estimation of fetal age. This study evaluated serial transrectal and transabdominal ultrasonography for monitoring embryonic and fetal development in Damascus (Shami) goats (Capra aegagrus hircus) (n = 7 carrying to term, including 4 singleton and 3 twin pregnancies). Using 4.0–6.5 MHz linear probes from day 15 to day 128 post‑mating, we measured twelve fetal parameters. Placentome diameter, biparietal diameter, occipito‑nasal length, thoracic diameter, fetal heart rate, transverse heart diameter, orbit diameter, umbilical cord diameter, and kidney diameter all yielded strong correlations with gestational age (R²= 0.98–0.99), allowing construction of reliable regression equations. Embryonic vesicle diameter, crown‑rump length, and amnion vesicle diameter provided insufficient data for modelling. Maternal serum progesterone (ELISA) remained higher in twin than in singleton pregnancies (P < 0.001), with significant differences emerging on days 51, 107, 114 and 128 (P < 0.05). Progesterone levels correlated negatively with birth weight. Ultrasonographic fetometry offers a practical, breed‑specific tool for gestational dating in goats, and progesterone measurement can assist litter size assessment during specific gestational windows.