Riding for a Fall

This first novel is billed as ""a Veterinarian Mystery."" Most vets don't also play polo, give CPR to an old beau who tried to commit suicide after being accused of murder or become as concerned with the trafficking of thoroughbreds as does Andi Pauling. The action revolves around her clinic in the Southern California desert, and there is too much of it to keep track of easily. However, once readers master overlapping plots and overpopulation of villains (including a violent fringe group of animal-rights activists), the author's good humor and delightful empathy with animals, from a nutty abandoned mutt to hysterical equines, provide an unusual take on the underground horsey set. Gore, especially in medical procedures, coexists with often funny asides. (Dec.)