Reproduction results and offspring performance after non-surgical embryo transfer in pigs

Increased interest in transfer of valuable genetic material around the world with minimal health risks has stimulated the development of non-surgical embryo transfer (nsET) technologies in pigs. Experimental evidence shows that nsET without sedation of the recipients is now feasible. The goal of this study, therefore, was to evaluate a method of nsET under commercial conditions. The experiment included 135 donor gilts and 45 multiparous recipient sows. Ovulation was induced in both donors and recipients, and nsET was performed using the Swinlet (R) catheter. Donor gilts averaged 16.5 (7-45) corpora lutea, but this depended on age of the donor (P < 0.05). An average of 10.1 transferable blastocysts was recovered per donor, and the recovery rate was 84%. For 44 nsET, 14 recipients (31%) came into estrous before Day 23 after ovulation, 7 recipients (16%) came into estrous between Days 23 and 30, 3 recipients (6.8%) came into estrous between Days 39 and 48, 2 recipients (4.5%) had a late abortion. Finally, 18 of 44 recipients (41%) resulted in successful births, with an average liter size of 7.2 +/- 2.8. Birth weight of nsET piglets were 0.2 kg more than control piglets, but depended on litter size (P < 0.05). The sex-ratio was not different from 50%. No anatomical abnormalities were observed in the offspring of nsET. Of the recipients that did not become pregnant from nsET, 91% became pregnant after insemination in the next estrous. Gilts born from nsET gave on average 12.4 +/- 3.0 total born piglets in their first pregnancy. In conclusion, the nsET procedure used in this study can be applied in practice without the need for special facilities, such as surgical and anesthesia equipment. (c) 2003 Elsevier Inc. All rights reserved.