Ovarian and uterine two-dimensional and Doppler ultrasonographic changes in the feline peri-estrus period

Abstract

Objectives The aim of this study was to evaluate two-dimensional and Doppler ultrasonographic changes of the ovary and uterus during estrus and the early post-estrus period in domestic cats. Methods Two-dimensional and Doppler ultrasonographic evaluations of the ovaries and uterus were performed in seven queens on days 1, 3 and 5 of estrus, and 5 days after estrus (AE5). Results On day 1, 5.4 ± 0.5 follicles of 2.1 ± 0.1 mm were detected progressively increasing in number and size up to day 5 and then decreased on AE5 ( P <0.05). A maximum follicular diameter of 4.1 ± 0.1 mm was achieved on day 5. Both during and after estrus, the uterus was generally hypoechoic compared with the surrounding tissues and delineated by a thin hyperechoic line corresponding to the serosa. In some animals, the uterine layers were distinguished during and after estrus. The blood flow waveforms of the intraovarian and uterine arteries were characterized by a systolic peak and diastolic flow extending throughout the remainder of the cardiac cycle to the next systole. In the uterine artery waveforms, the early diastolic notch was mild or absent during most estrous observations. The resistance index of the intraovarian arteries decreased up to day 5, and then increased on AE5 ( P <0.05). The resistance index of the uterine arteries was lower during estrus than in the post-estrus period ( P <0.05). Conclusions and relevance It is concluded that in the domestic cat, follicular number and diameter as well as ovarian and uterine blood flow changed during and immediately after estrus. Doppler ultrasound proved suitable to evaluate the hemodynamic changes involved in the cyclic remodeling of ovarian and uterine tissues that occurs during and after follicular growth in domestic cats.

Scientific and technical assistance on welfare aspects related to housing and health of cats and dogs in commercial breeding establishments

“…Different studies identified the reproductive aspects of queens including ovarian morphology and blood flow in prepubertal and pubertal cats (Vercellini et al., 2018 ), the normal reproductive tract (Davidson and Baker, 2009 ), pregnancy diagnosis and characterisation (Davidson et al., 1986 ), follicular development and oocyte quality in pre‐pubertal cats (Uchikura et al., 2010 ), changes that occur in ovary and uterus during oestrus and the early post‐oestrus period (Vercellini et al., 2022 ). Identifying and understanding the pre‐pubertal and pubertal changes that occur in the reproductive tracts may be helpful for breeders and owners of cats to decide when to start breeding their cats.…”