No abstract

The aim of this research was to evaluate the effectiveness of three pFSH doses (80 mg; 145 mg and 215 mg) on ovarian response and on quantity and quality of transferable embryos of goats during the breeding and the non-breeding seasons. Ovary structures were exposed (laparatomy under general anaesthesia) and numbers of follicles and corpora lutea were registered. Surgical embryo flushing was conducted to count and classify embryos. There were more follicles (3.4 ± 1.1) in does administered 80 mg of pFSH (p < 0.05) than in goats administered 145 mg of pFSH (2.2 ± 1.1) and 215 mg of pFSH (0.9 ± 0.6). Numbers of corpora lutea, blastocysts, and recovered and transferable embryos of goats administered 145 mg pFSH (13.4 ± 3.7, 2.42 ± 1.0, 3.4 ± 1.2 and 3.2 ± 1.1, respectively) and those of goats administered 215 mg pFSH (11.6 ± 2.6, 3.2 ± 0.9, 5.7 ± 1.5, and 5.6 ± 1.5) were greater (p < 0.05) than values obtained from goats administered 80 mg pFSH (4.0 ± 1.5, 0.5 ± 0.3, 1.0 ± 0.5, and 0.8 ± 0.5). Numbers of morula of does administered 80 and 145 mg pFSH (0.4 ± 0.4 and 0.8 ± 0.3) were lower (p < 0.05) than those obtained from animals treated with 215 mg pFSH (2.4 ± 0.9). There was no effect of season upon the analyzed variables. In conclusion, under the prevalent conditions in north-eastern Mexico, administration of 145 or 215 mg pFSH in a decreasing dose schedule over 3.5 days to bred goats provided a satisfactory superovulatory result.

In modern cattle breeding, assisted reproductive technologies in small ruminants have been used even out-of-season breeding, but in emerging countries these technologies have been mainly used for estrous synchronization and artificial insemination. However, in the last 30 years, significant progress in the matter of transfers of in vivo derived and in vitro produced embryos has been achieved. Currently, eight donor embryos are obtained by goat, due to the physiological knowledge of the presence of dominant follicles; above alter results recovered embryos (4 embryos / donor). Whereas, the goat has the advantage of presenting a shorter interval between generations compared to cow; this promote more research in in vitro fertilization, and overcome the limitations presented in a traditional embryo transfer. However cloning and transgenesis, are two techniques that will begin to have a commercial application, because goats can be used as bioreactors to produce milk with specific proteins to develop drugs. The objective of this study was to establish and describe in a general way the use of these techniques in goats, to promote their use so as to achieve genetic improvement in goats.

Ledezma-Torres (2018) The reinsertion of controlled internal drug release devices in goats does not increase the pregnancy rate after short oestrus synchronization protocol at the beginning of the breeding season,