Sperm production, testicular size, serum gonadotropins and testosterone levels in Merino and Corriedale breeds D. Fernandez-Abella, D. Becu-Villalobos, I.M. Lacau-Mengido, N. Villegas and O. Bentancur Reprod. Nutr. Dev., 39 5-6 (1999) 617-624 DOI: 10.1051/rnd:19990508