Transvaginal ovum pick-up (OPU) in the cow: a new disposable needle guidance system.

A study was conducted to modify the routinely used ovum pick up (OPU) devices to permit use of disposable needles and to simplify the technique and to make it more economical and practical to use. Long nondisposable needles are commonly used in transvaginal OPU despite several disadvantages. A new OPU device was developed using 19-g disposable needles to eliminate these disadvantages and to make the technique more successful. The disposable needle was connected to silicone tubing by means of a stainless steel connector. The system was inserted into a stainless steel tube, creating a rigid structure within which to move the needle back and forth. A blunt needle can be changed simply by replacing it with a new one, even while the device is in the vagina of a cow. The needle guidance system is incorporated into a new OPU device together with the transducer of an ultrasonographic scanner with an unilateral orientated scanning field, making it possible to utilize the needle length to its maximum. This combination permits easy manipulation of the ovaries, easy positioning of follicles on the puncture line, and enables the use of shorter needles which directly enter the scanned area without loss of useful needle length. As a preliminary result we obtained an overall oocyte recovery rate of 42%. Although this is promising, additional puncture sessions are needed to establish more consistent recovery rates. When OPU is used routinely, application of short disposable needles is more practical and economical.