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1.2.1.3 Transvaginal sonographic puncture of fołlicles

Transvaginal follide punctnres can be used to colłect fluid from preovulatoiy follides or to attempt the ębllection of oocytes. The same instrumentation that was designed for transvaginal conceptus punclures was applied for this purpose (see Chapter 1.3.2.6) using a simiiar technique. The automated puncture devioe, cov-ered by a protective plastic sleeve, was introduced into the anterior vagina where it was gently pushed against the yaginal wali. Using a rectally introduced hand, the ovaiy was then brought towards the tip of the ultra-sound probe. When it was evident on the monitor that the follide was aligned in the direction of and for the correct depth of the puncture needle the automatic puncture device could be triggered (Fig. 1.18).

Using this technique it was possible to aspirate folli-cułar fluid. Using a double barreled needle it was possible to continuously flush a follide; with a single barreled needle foDides could be filled and the flushing fluid aspirated repeatedty.

Immediately after a follide had been punctured it was eńdem that intrafollicular hemorrhage occurred (Fig. 1.19). Within only a fcw minutes the follicular cav-ity filled with blood which exhibited intcnsive echoge* nicity. Within this hemorrhage, tmbuJenoes, indicative of the streaming of blood into the follide, were seen on the real-time ultrasound image. The edent of hemorrhage was simiłar to that seen at the sitc of the futurę corpus luteum after spontaneous ovulations (sec Chap-ter 1.2.2.2). Thus far no disorders have been obseived in mares after follide puncture.

When the puncture site was examined ultrasonically during the next few days, the formation of a structure not unlike that of a corpus luteum could be observed (Fig. 1.20). A single puncture of a follide shortly before its antidpated ovulation did not affect the development of a normal corpus luteum thereafter (Carnevale et al. 1988 a). In some mares whose follides were punctu-red, lower plasma progesterone concentrations were measured during the first 3 to 5 days after puncture than in mares that ovulated without interferencje. This difference in progesterone secretion was, however, not evident after Day 8 of the cyde. Cyde length and the ensuing estrus of mares were not affected by follide puncture.