Contraceptive Strategies for Female Cattle: Efficacy and Zootechnical Aspects.

Unwanted pregnancies at the slaughterhouse are a recurring problem globally, compromising ethical aspects and animal welfare, and causing production losses. This review explores contraceptive strategies for female cattle, focusing on both management practices and suppression of the estrous cycle and/or fertilisation. Contraceptive techniques such as surgical castration, emasculation of the ovaries with rubber rings, intrauterine devices (IUDs), GnRH agonist implants, and immunocastration are discussed. Surgical castration, although efficient, is an invasive procedure that compromises animal welfare. Alternative methods, such as IUDs and GnRH implants, lack commercially available products and large-scale efficacy studies. Immunocastration is easy to apply and does not require specialised equipment, but also requires further studies to evaluate its effects on animal performance. Despite the various contraceptive alternatives available, the high number of pregnant females slaughtered highlights the need for awareness among producers and technicians, as well as more in-depth studies on strategies that can promote benefits to animals and production.