Morphometry of ovarian structures by transrectal ultrasonography in Serrana goats

Abstract

The accuracy of transrectal real-time ultrasonography (RTU) scanning technique to detect ovarian structures (follicles and corpus luteum) of Serrana goats was compared to the data obtained by observation of ovarian sequential slices. This slicing technique (SLI) was considered as reference method. The laparoscopy and laparotomy techniques were also used for corpora lutea identification. For this purpose the ovaries of 14 females were observed, 7-8 days after ovulation, by transrectal ultrasonography followed by laparoscopic examination. Then ovaries were removed and studied by slicing. In the sliced sections of each ovary (n = 28), follicles and corpus luteum (CL) were identified and counted. CL and follicular diameters were measured using a millimetre scale.The total number of follicles, counted by RTU, was significantly lower than that observed by SLI (P < 0.01). This difference was mainly due to the under estimation of <2 mm follicles category. The correlation coefficient between category data obtained by RTU and SLI methods for the number of follicles ≥3 mm was high (r 2 = 0.95, P < 0.001), which highlights the use of UTR as a potential methodology to study the follicular dynamic of goats.There were no significant differences (P > 0.05) between the average number (mean ± S.D.) of corpus luteum identified per ovary by RTU (0.71 ± 0.75), laparoscopy (0.58 ± 0.71), laparotomy (0.67 ± 0.76) or SLI (0.83 ± 0.76) methods. The accuracy for the identification of ovulation, validated by CL detection on D7-D8 by SLI (100%), was 91.7%, 87.5% and 83.3% by RTU, laparotomy and laparoscopy, respectively. The negative predictive value of RTU, laparotomy and * Corresponding author. E-mail address: jsimoes@utad.pt (J. Simões). Simões et al. / Animal Reproduction Science 85 (2005) [263][264][265][266][267][268][269][270][271][272][273] laparoscopy to verify the absence of a CL in the ovary was 81.8%, 75.0% and 69.2%, respectively. The specificity of all three methods for the CL identification was 100%. No significant differences (P > 0.05) were found in the probability to detect the exact number of CL (0, 1 or 2) counted in each ovary between the RTU (87.5%), laparotomy (83.3%) and laparoscopy (75.0%) methods when compared with the reference method. 0378-The diameter of spherical CL could be estimated with reliability (r 2 = 0.86; P < 0.001). The real-time ultrasonographic scanning proved to be a highly accurate method for detection and measurement of several categories of follicles and CL size in Serrana goats. The results of the present study show that laparoscopy and RTU are similarly reliable techniques for CL detection. However, the RTU represents a non-traumatic technique with advantages to animal welfare both in experimental and reproductive evaluation of the size of ovarian structures.

Luteal dynamics in goats: morphological and endocrine features

“…Ultrasography is considered an efficient tool to identify ovarian structures. The sensibility and efficiency of this technique were previously demonstrated by Viñoles et al (2004) in ewes and by Simões et al (2005) in goats. In the present study, the mean moment of first corpus luteum visualization was Day 5 of estrous cycle (ranging from Day 4 to 7).…”

“…The use of transrectal ultrasonography in small ruminant was a hallmark in the 1990s, and important studies on ovarian physiology could be done. The ultrasonography technique allowed the identification of ovarian structures in goats with a sensitivity and specificity similar to those observed in surgical methods (Simões et al, 2005). The first sonographic studies on ovarian function, however, focused on follicular dynamics (Medan et al, 2003), and only recently, luteal activity was systematically studied in this specie (Simões et al, 2007).…”

Time of ovulation in nulliparous and multiparous goats

“…Sonograms were recorded using a digital video for retrospective image computer analysis. The UTHSCSA R (University of Texas Health Science Center at San Antonio, San Antonio, TX, USA) Image Tool 3.00 software was used for follicle count and measurement as described by Simõ es et al (2005b). Ovulation of a preovulatory follicle was considered to occur when one follicle, greater than 4 to 5 mm in diameter and observed in the previous scanning, had disappeared ( Figure 1).…”

Origin and characterisation of preovulatory follicles of hyperstimulated oestrous cycles in goats

“…Both ovaries were scanned, with the goats kept in standing position and restrained in an appropriate cage as described by Simões et al (2005). Between days 5 and 10 after the second natural oestrus an ovarian ultrasound examination was also performed to count the corpora lutea.…”