Sensitivity to gentamicin of Escherichia coli isolated from foals: comparison of two laboratory methods

Abstract

centage of cleaved embryos increased to 32 per cent and 49 per cent, respectively.When counting the ovulations a high proportion of ovaries with follicles >5 mm in diameter was observed as estimated by comparing the follicles with the size of the instruments used for flushing. DiscussionThe laparoscopic technique described can be highly efficient for collecting pronuclear-stage goat embryos. The overall recovery rate of 77 per cent obtained in the two sessions is comparable with or higher than that reported by authors who used laparotomy as distinct from laparoscopy procedures (Selgrath and others 1990). The lower incidence of postoperative adhesions after laparoscopy, also observed by McKelvey and Robinson (1986), justifies the use of this technique. It should be mentioned that skill in laparoscopy takes time to acquire but the time needed for flushings and embryo recovery rates were improved with practice.To obtain pronuclear-stage embryos from Saanen goats treated with FSH and prostaglandin the optimal time for flushing the oviducts was 75 to 78 hours after the injection of prostaglandin. This correlates closely with the results of Selgrath and others (1990) who found 72 to 79 hours after the removal of progestagen implants to be optimal for the collection of one-cell embryos.Further research is required to find the optimal superovulation regimen for Saanen goats, and thereby to increase the efficiency of gene-transfer programmes. For example, at the time of flushing a large number of unovulated follicles was found at the surface of the ovary. It is probable that a superovulation protocol including the administration of gonadotrophin-releasing hormone could increase the ovulation rate.