Utilização da ultrassonografia Doppler na avaliação do fluxo sanguíneo dos corpos lúteos suplementares em éguas cíclicas

Abstract

The theme of this study is the use of Doppler ultrasound in evaluating the blood flow of corpus luteum accessories (CLA) in cyclical pregnant mares because this technique associated with conventional ultrasound, has shown great value in assessing the hemodynamic aspects of the reproductive organs mares, aiding in assisted reproduction programs. It is known that the maintenance of pregnancy requires constant synthesis of progesterone and, given the close relationship between the vascular perfusion of the corpus luteum (CL) and CLA and the serum concentration of progesterone, Doppler ultrasound can be used at the time of inovulation of the embryo to evaluate the functionality of corpus luteum. Thus, this study aimed to describe the ultrasound changes of CLA in pregnant mares using the Doppler ultrasound technique. The study brought two problem issues: the first is the formation of CLA by mares is really needed to keep their pregnancy; and the second is whether it is possible to estimate a good vascularization of the CLA without the need to use the programs to evaluate pixel, that is, the subjective evaluation is reliable and efficient for field veterinarian? The hypothesis defended in this research are that the formation of CLA is essential for maintaining pregnancy in mares, and that the subjective assessment can be rather reliable for field veterinarian. For this, the study monitored 20 crossbreed mares pregnant (n = 20) to follow the onset and development of CLA, these then analyzed for their haemodynamic through Doppler ultrasound. The results of this research show that 75% of the evaluated mares formed CLS, with no significant differences between the number of CLS in terms of objective and subjective evaluations (P> 0.05), but with differences in time of formation of CLA in relation to subjective evaluations, pixel and pixel intensity (p> 0.05). It was also observed that vascular perfusion (VP) luteal from 70 days of gestation did not differ between the degrees of variables, getting the most out of the vasculature to the 119 days, indicating the most mature CLA and, from that period, can realize a decrease of VP structures. The study demonstrated that the subjective evaluation is reliable and efficient for field veterinarian, however, five mares (n = 5) of the study did not develop CLA and still maintained their pregnancy, contradicting the hypothesis that the study advocated. To add more data on the subject, it is recommended to extend this research to the joint assessment of formation CLA with blood dosage of progesterone and chorionic gonadotropin equine.