Feline embryo ~ 21-23 days
Key words: Embryo, feline, organogenesis, crown-rump, genital ridge.
Click on the image to enlarge it.
A feline embryo estimated to be approximately 21 to 23 days of age based on its (difficult to ascertain) crown-rump length and physical appearance in an image from Knospe, C. 2002.
Besides the intriguing organogenesis, of special interest to the author was the genital ridge. It is particularly obvious in this specimen. This structure is well known to reproductive biologists as the progenitor of the gonads; a ridge populated by primordial germ cells from the yolk sac. These cells migrate to the ventral aspect of the mesonephros on either side of the spinal column. In this specimen it is not possible to determine if the gonads will develop into ovaries or testes.
The author extends thanks to Dr Glenda Wright (gwright@upei.ca) and Dr Vanmathy Kasimanickam (vkasiman@wsu.edu) for their editorial comments on this image.
Selected references:
Davidson, A.P. et al. 1986. Pregnancy diagnosis with ultrasound in the domestic cat. Vet. Radiology and Ultrasound. 27:109-114
Knospe, C. 2002 Periods and Stages of the Prenatal Development of the Domestic Cat. Anat. Histol. Embryol. 31:37–51
Luvoni, G.C. 2013. Ultrasonographic Foetal Biometry in Dogs and Cats. WSAVA2013 - VIN
Nelson, N.S. and Cooper, J. 1975. The growing conceptus of the domestic cat. Growth 39:435-451
Topie, E. et al. 2015. Early pregnancy diagnosis and monitoring in the queen using ultrasonography with a 12.5 MHz probe. J.Feline Med.Surg. 17:87-93
