Efficacy of two types of vaginal sponges to control onset of oestrus, time of preovulatory LH peak and kidding rate in goats inseminated with variable numbers of spermatozoa - Leboeuf, B; Forgerit, Y; Bernelas, D; Pougnard, JL; Senty, E; Driancourt, MA (Theriogenology, 2003)