| Title: | Equine chorionic gonadotrophin administration to rams improves their effectiveness to stimulate anoestrous ewes (the 'ram effect') |
| Author(s): | Ungerfeld R; Clemente N; Bonjour L; Orihuela A; |
| Address: | "Departamento de Fisiologia, Facultad de Veterinaria, Universidad de la Republica, Lasplaces 1620, Montevideo 11600, Uruguay. Electronic address: rungerfeld@gmail.com. Facultad de Ciencias Agropecuarias de la Universidad Autonoma del Estado de Morelos, Cuernavaca CP 62240, Morelos, Mexico. Departamento de Fisiologia, Facultad de Veterinaria, Universidad de la Republica, Lasplaces 1620, Montevideo 11600, Uruguay" |
| DOI: | 10.1016/j.anireprosci.2014.07.004 |
| ISSN/ISBN: | 1873-2232 (Electronic) 0378-4320 (Linking) |
| Abstract: | "Ewes' response to ram effect is related to the strength of androgen-dependent ram signals. Experiment 1 aimed to determine if the administration of a single dose of 1000IU of eCG to rams three days before joining them with ewes enhance their ability to stimulate females. Based on the results of Experiment 1, in a second experiment rams received two doses seven and three days before their introduction to females. In Experiment 1, rams treated or not with eCG were joined with ewes, and estrous was recorded until Day 5 (Day 0=rams and ewes were joined), and from Day 15 to Day 23. In addition, serum testosterone concentration was measured in all rams in the first recorded period. Testosterone values were greater in eCG-E1 than in Con-E1 rams on Days 0 and 2. The percentage of ewes in estrus was similar in both groups. In Experiment 2, rams were treated with two doses of eCG on Days -7 and -3 or remained as untreated controls. Estrous was recorded until Day 5, and pregnancy rate on Day 46; testosterone was measured in samples collected from all rams. Testosterone concentration was greater in eCG-E2 than Con-E2 rams from Day -5 to Day 1, and tended to do so on Day 2. More eCG-E2 than Con-E2 ewes came into estrus and became pregnant. It was concluded that treatment of rams with two high doses of eCG before joining them with anestrous ewes, enhanced their ability to induce ewes' cyclic activity (the 'ram effect')" |
| Keywords: | "Animals Chorionic Gonadotropin/*pharmacology Estrus/*physiology Female Male Pregnancy Sexual Behavior, Animal/*drug effects Sheep/*physiology Testosterone/blood/metabolism Gonadotropin Pheromones Reproductive seasonality Socio-sexual signals Testosterone;" |
| Notes: | "MedlineUngerfeld, Rodolfo Clemente, Neftali Bonjour, Lorena Orihuela, Agustin eng Controlled Clinical Trial Netherlands 2014/07/26 Anim Reprod Sci. 2014 Oct; 149(3-4):194-8. doi: 10.1016/j.anireprosci.2014.07.004. Epub 2014 Jul 11" |
