The present study aimed to investigate the conceptus-related changes during early pregnancy in the Black Bengal breed of goat. A total of 22 gravid genitalia of the Black Bengal goats were collected from local slaughterhouses. The crown-rump lengths (CRL) of the conceptuses were determined to estimate the gestational age (GA). The length and diameter of uterine horn and amniotic sac were measured, and volume of amniotic and allantoic fluid formed by individual conceptus were recorded. The results reveal that the CRL is positively correlated with GA of the conceptus (R2 = 0.89, p < 0.05); however, CRL was not influenced by number of conceptus. Both the left and the right uterine horn gradually increased in size with the advancement of pregnancy irrespective of conceptus number present in the horn. The size of the amniotic sac of conceptus gradually increased with the conceptus age but maintained spherical shape from 5 to 7 weeks of pregnancy. The amniotic fluid formed by individual conceptus rapidly increased from 5 weeks (3.4 ± 0.3 mL) to 7 weeks (21.0 ± 2.0 mL) and 9 weeks (111.5 ± 4.0 mL). The volume of allantoic fluid formed by individual conceptus was steadily increased until 7 weeks (60.0 ± 5.0 mL) and began to decline slowly thereafter (50.0 ± 5.0 mL at 9 weeks). Notably, there was no effect of conceptus number per pregnancy on individual amniotic and allantoic fluid volume. The cotyledons have first appeared on the allanto-chorionic surface from 4 to 5 weeks of pregnancy. The closed eye, nostril and hooves of the conceptus became visible at 7 weeks of pregnancy. The present study has shown the basic information on conceptus-related developmental changes during early pregnancy up to 9 weeks in Black Bengal goat.

ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
CONCLUSION
CONFLICTS OF INTEREST
ACKNOWLEDGEMENTS
AUTHOR CONTRIBUTIONS
AUTHOR’S POSITION AND ORCID NO
REFERENCES

• Anup K. Talukder(Department of Gynecology, Obstetrics & Reproductive Health, Faculty of Veterinary Medicine & Animal Science, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh) Corresponding author
• Mohammad A. Rahman(Department of Surgery & Radiology, Faculty of Veterinary Medicine & Animal Science, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh)
• Mohammad N. Hoque(Department of Gynecology, Obstetrics & Reproductive Health, Faculty of Veterinary Medicine & Animal Science, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh)
• Mohammad T. Islam(Department of Pathobiology, Faculty of Veterinary Medicine & Animal Science, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh)
• Abu N. M. A. Rahman(Department of Gynecology, Obstetrics & Reproductive Health, Faculty of Veterinary Medicine & Animal Science, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh)
• Ziban C. Das(Department of Gynecology, Obstetrics & Reproductive Health, Faculty of Veterinary Medicine & Animal Science, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh)