Ultrasound biometry for estimating delivery dates in small and medium breed cats.

This research investigated the development of fetal and feto-maternal structures and their correlation to the time leading up to parturition during pregnancy in small and medium breeds of domestic cats. The experiment involved 53 purebred queens assigned to two groups based on their weight. Ultrasound examinations were performed weekly from the 15th day after the last mating until delivery. The inner chorionic cavity (ICC) was measured from pregnancy confirmation up to 35 days before parturition. Crown-rump length (CRL) was measured between 43 and 28 days before parturition. Biparietal diameter (BPD), abdominal diameter (AD), femur length (FL), kidney length (KL), and eye diameter (ED) were assessed from the time they were first accessible via ultrasound examination until delivery. The results indicated that CRL, BPD, and FL are the most suitable parameters for estimating the date of parturition in cats, while ED and KL can serve as useful supplementary parameters.