Title: | The 'male effect' in sheep and goats--revisiting the dogmas |
Author(s): | Delgadillo JA; Gelez H; Ungerfeld R; Hawken PA; Martin GB; |
Address: | "Centro de Investigacion en Reproduccion Caprina, Universidad Autonoma Agraria Antonio Narro, Periferico Raul Lopez Sanchez y Carretera a Santa Fe, Coahuila, Mexico. joaldesa@yahoo.com" |
DOI: | 10.1016/j.bbr.2009.02.004 |
ISSN/ISBN: | 1872-7549 (Electronic) 0166-4328 (Linking) |
Abstract: | "Male-induced ovulation in sheep and goats (the 'male effect'), documented during the period 1940-1960, has long been shrouded in preconceptions concerning how, when and why it worked. These preconceptions became dogmas but recent research is challenging them so, in this review, we have re-visited some major physiological (breed seasonality; characteristics of the response; the nature of the male stimuli) and physical factors (duration of male presence; isolation from male stimuli) that affect the phenomenon. We reject the dogma that ewes must be isolated from males and conclude that male 'novelty' is more important than isolation per se. Similarly, we reject the perception that the neuroendocrine component of the male effect is restricted to anovulatory females. Finally, we re-assess the relative importance of olfactory and non-olfactory signals, and develop a perspective on the way male-induced ovulation fits with preconceptions about pheromonal processes in mammals. Overall, our understanding of the male effect has evolved significantly and it is time to modify or reject our dogmas so this field of research can advance. We can now ask new questions regarding the application of the male effect in industry and develop research so we can fully understand this biological phenomenon" |
Keywords: | "Animals Female Goats/*physiology Gonadotropin-Releasing Hormone/physiology Instinct Luteinizing Hormone/physiology Male Ovulation/*physiology Pheromones Sexual Behavior, Animal/physiology Sheep/*physiology Vomeronasal Organ/physiology;" |
Notes: | "MedlineDelgadillo, J Alberto Gelez, Helene Ungerfeld, Rodolfo Hawken, Penelope A R Martin, Graeme B eng Research Support, Non-U.S. Gov't Review Netherlands 2009/04/18 Behav Brain Res. 2009 Jun 25; 200(2):304-14. doi: 10.1016/j.bbr.2009.02.004" |