B mode and Doppler ultrasonographic characteristics of the dominant follicle and corpus luteum in Criollo cows subjected to an oestrus synchronization protocol

The objective was to determine the ultrasonographic B mode and Doppler characteristics of the dominant follicle and corpus luteum in Criollo cows subjected to an oestrus synchronization protocol. The study was conducted at the Agricultural Experimental Station ILLPA during the months of May to July using 15 Criollo cows with regular body condition and fed with natural pasture, the protocol consisted of placing estradiol benzoate and intravaginal device on the first day, then on day 7 the device was removed and an analogue of Prostaglandin F 2α was applied, On day 8 estradiol benzoate was applied again and on day 9 artificial insemination was performed with semen from a single Fleckvieh sire, ultrasonographic evaluation was performed on days 7 and 9 (synchronization started) to determine the diameter of the dominant follicle, growth rate and diameter of the uterine horn, the evaluation of the corpus luteum was performed on day 19 determining the diameter, volume and luteal vascular area (%), all the analyses were performed with the Jamovi 1 Programme. 6.23.0. The results of the dominant follicle on day 7 was 8.69 mm and day 9 was 10.7 mm with a growth rate of 1.14 mm/day, the diameter of the right uterine horn was 11.85 mm (day 7) which increased to 15.32 mm (day 9) while the left horn increased from 12.72 to 16.27 mm. 72 to 16.27 mm, the characteristics of the corpus luteum were 7.96 mm diameter, volume 0.23 mm3 and luteal vascular area was 20.96 %, finally, the pregnancy rate obtained was 6 cows out of 15 inseminated which represents 40 %. In conclusion, the diameters and volume of the dominant follicle and corpus luteum are lower than those reported in other breeds in the same environmental conditions, the luteal vascular area was 20.96 %, the proportion of blood irrigation of the CL in Criollo cows and finally the pregnancy rate was 40 %. However, it is necessary to point out that these are the first reports of Doppler characteristics in Criollo cows