Girth (tack) often used in addition to a regular leather girth. Made of leather or nylon with an elastic insert (for racing), the overgirth completely encircles the horse around belly and the saddle's seat. It is used by stockmen, eventers, polo players, in flat racing, and by steeplechase jockeys to provide more security in holding the saddle in place. Some girths (those used on jumpers and eventers) have a belly guard (or stud guard), to protect the belly from being stabbed by horseshoe studs as the animal tucks his legs up underneath him over a tall obstacle. The traditional western cinch was
Animal testing on frogs which reaches its reproductive age in five months rather than one to two years (as in "X. laevis"), facilitating faster studies across generations. The genome sequence of "X. tropicalis" was scheduled to be completed by 2015 at the latest. Frogs are widely used in classroom dissections and teaching exercises. Animal testing on frogs Frogs have been used in animal tests throughout the history of biomedical science. Eighteenth-century biologist Luigi Galvani discovered the link between electricity and the nervous system through studying frogs. The African clawed frog or platanna, "Xenopus laevis", was first widely used in laboratories in pregnancy assays in