Ultrasonographic and endocrine characterization of follicular waves in llamas with a special reference to the overlapping phenomenon during successive waves

• Autores: Cavilla, María Verónica; Bianchi, Carolina Paula; Maistruarena, C.; Aba, Marcelo Alfredo
• Año de publicación: 2013
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Follicular Activity; Oestradiol; Llamas
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Ovarian follicular growth in non-mated llamas occurs in  successive waves that generally superimpose their origin on the  regression of the preceding wave (overlapping), originating  prolonged sexual receptivity in the species. The aim of this  study was to perform an ultrasonographic and endocrine  characterization of individual and successive waves in nonmated  llamas with a special interest on the overlapping  phenomenon. Twelve llamas were examined daily by transrectal  ultrasonography for at least two consecutive waves. In six  females, blood samples were collected daily at the end of each  examination. The development of the largest follicle (F)  showed a wavelike pattern with a mean duration of 25 days.  All waves evaluated were partially overlapped on the preceding  wave and emerged at a mean interval of 15.8 0.5 days.  This interwave interval determines a mean overlapping degree  of 32% of the wave length. Similarly, mean plasma oestradiol-  17b (E2) concentrations followed a wavelike pattern. However,  E2 concentrations started to decline before the structural  regression of the F was observed. Mean basal E2 concentrations  remain higher than 10.9 0.6 pmol/l. In conclusion,  follicular activity in non-mated llamas is characterized by  continuous emergence of successive waves that always overlap  the preceding wave with variable degrees. E2 production  during the follicular wave is shorter in duration than the  morphological development of the F. Finally, the overlapping  phenomenon maintains increased plasma E2 concentrations  persistently and this could explain the prolonged periods of  sexual receptivity registered in llamas.
Fil: Cavilla, María Verónica. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Endocrinología; Argentina;
Fil: Bianchi, Carolina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tandil. Centro de Investigacion Veterinaria de Tandil; Argentina;
Fil: Maistruarena, C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tandil. Centro de Investigacion Veterinaria de Tandil; Argentina;
Fil: Aba, Marcelo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tandil. Centro de Investigacion Veterinaria de Tandil; Argentina;