Researchers who want animal sperm -to study fertility or for artificial insemination-have a suite of attractive options: They can ram an electric probe up an animal's rectum, shove an artificial

vagina onto the animal's penis, or simply do it the old-fashioned way-manual stimulation. The first option, electroejaculation, uses a priapic rectal probe to send electricity pulsing through the animal's nether regions. "All the normal excitatory signals that stimulate ejaculation, like touch, sight, sound and smell, can be replaced with the current from the probe," says Trish Berger, professor of animal science at the University of California, Davis. "It's fascinating. Of course, this is a woman talking." Electroejaculation generally requires anesthetizing the animal and is typically used on zoo dwellers. The other two methods-the artificial vagina, or AV, and the good old hand-require that animals be trained to the procedure. The AV-a large latex tube coated with warm lubricant -is used primarily to get sperm from dairy bulls (considered the most ornery and dangerous of bovines). The bull gets randy with a steer; when he mounts the steer with his forelegs, a brave technician, AV in hand, insinuates himself between the two aroused beasts and deftly redirects the bull's penis into the mock genitalia, which he must then hold tight while the bull orgasms. (Talk about bull riding!) Three additional technicians attempt to ensure this (fool)hardy soul's safety by anchoring themselves to restraining ropes attached to a ring in the bull's nose. Alas, this isn't always absolutely effective: Everyone who's wielded an AV has had at least one close call, and more than a few have been sent to the hospital. The much safer "digital pressure" is used mostly with pigs, who are trained from an early age to mount a small bench while the researcher reaches around with a gloved hand and provides appropriate pleasure-er, pressure.