“…These cows, when untreated, cause disturbance in the herd during estrus and, additionally, are often pregnant at slaughter. In contrast to surgical methods (ovariectomy; Hobson and Hansel, 1972;Bleul et al, 2005), mechanical contraception methods (foreign objects in the uterus; Turin et al, 1997), or permanent administration of progesterone derivatives (Burns et al, 1993;Jacobsen et al, 1995;Denicola et al, 1997;Petta et al, 1998), immunological techniques represent an animal-friendly method for controlling populations (Miller et al, 2000;Curtis et al, 2002). Immunization against GnRH has been used to suppress sexual behavior and to prevent the development of secondary sexual characteristics in males (Finnerty et al, 1998;Cook et al, 2000;Thompson, 2000;D'Occhio et al, 2001;Aïssat et al, 2002;Janett et al, 2003Janett et al, , 2009bJanett et al, , 2012aTurkstra et al, 2005;Theubet et al, 2010) as well as in females (Dalin et al, 2002;Imboden et al, 2006;Elhay et al, 2007;Janett et al, 2009a).…”