Limitations of ultrasound guided follicular aspiration for analysis of ovarian follicular fluid in dairy cattle

Abstract

The aim of this study was to evaluate the applicability of ovum pick-up equipment for follicular fluid collection from various follicular structures (experiment 1) and for recovery of follicular fluid for acid-base balance analysis (experiment 2). An ultrasound scanner equipped with a 5-MHz convex transducer was used for transvaginal ultrasound-guided follicular aspiration. A 17-gauge, 60-cm aspiration needle was connected with a shortened aspiration line. The fluid was aspirated manually into a 2 ml plastic syringe at a speed of approximately 0.2 ml/s. The success of aspiration was higher in ovarian cysts (100%) and single follicles larger than 13 mm (76.7%) compared to single follicles smaller than 12 mm (20%, p < 0.001). The success of aspiration of multiple follicles on day 4 (diameter of 7-9 mm) was higher (90.9%) compared to follicles on day 2 (diameter of 4-6 mm) (66.7%, p < 0.05) in experiment 1. The fluid from ovarian cysts > 25 mm in diameter was aspirated in a two-step procedure (samples 1 and 2) for the determination of pH, HCO 3 , BE, pCO 2 and pO 2 (experiment 2). The indicators were compared between samples 1 and 2. Higher pO 2 as well as pH and lower pCO 2 in sample 1 compared to sample 2 showed insufficient anaerobic conditions during the first phase of the puncture in experiment 2. Our study brings for the first time the finding that the ovum pick-up equipment used in our experiments is suitable for the collection of follicular fluid only from larger follicular structures. The sampling of follicular fluid for acid-base balance assays requires the development of a special new device to prevent samples from coming into contact with air during aspiration.

A new device for the aspiration of follicular fluid for acid-base balance analysis in cattle

“…The values of estimated parameters in samples collected using the ABB set and the OPUe under anaerobic conditions were similar. With these results we have confirmed our previous findings (Cech et al 2011) that O 2 from air present in the aspiration needle and line passes into the sample, and that CO 2 escapes from the sample into the air present in the aspiration needle and line according to a concentration gradient. As a consequence of lower pCO 2 we found higher pH values.…”

“…Therefore, after insertion of the holder into the vagina it is present immediately in front of the ovary. Aspirated fluid does not have to travel as long a distance, as is the case for the older OPUe device, and thus, is not contaminated by air present in the aspiration system, as we demonstrated in a previous study (Cech et al 2011). We used our new ABB set for the aspiration of the first sample from each sequence, because we needed two repeated aspirations of each cyst; disposable 22G needles used in the ABB set cause lower mechanical trauma to the aspirated structure than the 17G needle used in the modified OPUe.…”

“…This has been associated with a decrease in the pH of follicular fluid (Daya 1988;Imoedemhe et al 1993). In our previous study we also observed preanalytical changes in O 2 , CO 2 and pH values when the samples of fluid from ovarian cysts were not taken under strictly anaerobic conditions (Cech et al 2011), and therefore we have formulated requirements necessary for the development of a new set for follicular fluid collection. The purpose of our study was to evaluate a new set for the aspiration of follicular fluid to be used in determining acid-base balance (ABB set).…”

“…Several articles in human medicine have addressed these factors (Shalgi et al 1972;Daya 1988;Imoedemhe et al 1993) and have focused especially on concentrations of carbon dioxide and pH in follicular fluid. However, the recovery of follicular fluid for acid-base balance and gas analysis from live animals is rarely described (Berg et al 2003(Berg et al , 2005Cech et al 2007;de Castro e Paula et al 2008), perhaps due to the technical difficulties involved in follicular fluid sampling. Peripheral blood collection for acid-base balance analysis is performed routinely.…”

Supplementation of dairy cows with docosahexaenoic acid did not affect ovarian activity

“…Follicular fluid for E2, P4, insulin-like growth factor 1 (IGF1), insulin, cholesterol, and NEFA determination was aspirated from preovulatory follicles on D42 (oestrus 2) in 10 cows (5 experimental and 5 control cows). Dominant follicles 15-20 mm in diameter were aspirated using a transvaginal ultrasound-guided follicular aspiration (TVFA) according to Cech et al (2011). The follicular fluid was aspirated manually into a 2 ml plastic syringe until the dominant follicle was aspirated completely.…”