Girth (tack) sensitive horses to protect the barrel of the horse, and some styles of girth come with attached or removable sheepskin liners that perform the same function. A dressage girth, or Lonsdale girth, is shorter than the usual girths used on other saddles. This is because the dressage saddle has longer billets, to keep the buckles out from under the rider's leg, and so a shorter girth may be used. Dressage girths can be made of all the materials, and in all the styles, mentioned before, and also can be made entirely of very strong elastic. An overgirth or surcingle is
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