Application of reproductive biotechnology for the recovery of endangered breeds: birth of the first calf of Murciana-Levantina bovine breed derived by OPU, in vitro production and embryo vitrification.

In a conservation project, reproductive biotechnology was implemented for the recovery and conservation of an endangered bovine breed in Spain. The breed Murciana-Levantina, declared to be worthy of special protection status (http://www.fao.org/newsroom/en/news/2006/1000464/index.html), is of great interest because of its hardness, longevity, docility and disease resistance. This contribution describes the birth of the first calf of this breed obtained by reproductive biotechnology, using ultrasound-guided punction and aspiration of ovarian follicles, in vitro embryo production, vitrification of embryos by a cryotop device and, finally, the transfer of cryopreserved embryos to recipient heifers of a commercial dairy herd.

Histochemical skeletal muscle fibre types in the sheep.

In this study, the differentiation of adult and postnatal muscle fibres in sheep longissimus thoracis muscle has been characterized. By using a variety of histochemical methods, we have investigated the m-ATPase and metabolic activities of skeletal muscle fibres in adult sheep and lambs aged between 1 day and 3 months. Types I, IIA, IIB and IIC fibres were identified. The results showed that the interpretation of the fibre type composition depends on the methods used. The findings also revealed that the fibre types IIA and IIB can be separated histochemically in sheep by using the correct m-ATPase technique, even at early stages of postnatal development, and that the origin of the four different fibres of the adult can be traced back to early postnatal stages.