The Recipients' Parity Does Not Influence Their Reproductive Performance Following Non‐Surgical Deep Uterine Porcine Embryo Transfer

Abstract

With the development of the non-surgical deep uterine (NsDU) embryo transfer (ET) technology, the commercial applicability of ET in pigs is now possible. There are, nevertheless, many factors that influence NsDU-ET effectiveness that need to be addressed. The aim of this study was to evaluate the effects of the weaned recipients' parity on fertility and prolificacy following NsDU-ET. The recipients (n = 120) were selected based on their reproductive history and body condition and grouped into three categories according to their parity: primiparous sows, sows of parity 2 and sows of parities from 3 to 5. Thirty fresh embryos (morulae and unhatched blastocysts) were non-surgically transferred into one uterine horn of each recipient. It was possible to insert the NsDU-ET catheter through the cervix along a uterine horn in 98.3% of the recipients. The parity had no influence on the difficulty grade of the insertions or on the percentage of correct insertions. The cervix and uterine wall were not perforated during the insertions, and vaginal discharge was not observed after transfer in any of the recipients. There were no differences in the pregnancy rates (74.8%), farrowing rates (71.2%) or litter sizes (9.6 ± 3.3) between groups. Also, there were no differences between groups regarding to the piglets' birthweights or piglet production efficiency. In conclusion, these results demonstrate that weaned sows from parity 1 to 5 are appropriate to be used as recipients in NsDU-ET programs, which increase the possibilities for the utilization of ET in the recipient farms.

Achievements and future perspectives of embryo transfer technology in pigs

“…Multiparous sows are ideal as recipients because the insertion of the NsDU‐ET catheter is easier, their conduct during the transfers is better (Martinez, Cuello et al., ), and their oestruses are naturally and effectively synchronized by managing weaning. All of the abovementioned observations led us to evaluate the influence of recipient parity (parity 1 to 5) on NsDU‐ET outcomes (Martinez, Nohalez et al., ). The results indicated that neither the efficiency of the NsDU‐ET procedure nor the reproductive performance of the recipients were affected by parity.…”

Surgical embryo collection but not nonsurgical embryo transfer compromises postintervention prolificacy in sows

“…These data, together with the excellent fertility results following NsDU-ET [2][3][4][5][6], suggest that the insertion of the catheter does not cause significant damage to the cervix and/or uterine horn. The results of the present study parallel earlier studies and reinforce the suggestion that NsDU-ET is a non-invasive and welfare-preserving technology.…”

“…Secondly, the use of recipient sows was preferred because weaning is a physiological, regular and outstanding process that facilitates estrus synchronization in swine [19]. Thirdly, the parity of the recipient does not affect the success of NsDU-ET [6] and finally, the use of recipient sows with a wide parity range facilitates the scheduling of ET in the recipient farms due to the higher availability onfarm.…”

“…Several factors affecting the success of the NsDU-ET procedure, including superovulation of the donors, synchrony between donors and recipients, use of fresh, short-term or long-term stored embryos, number of embryos transferred per recipient and the recipient's parity, have all been recently assessed [2][3][4][5][6]. However, other factors not directly related to the success of ET have to be quantified to properly estimate the final costs of porcine ET, a most relevant factor for the successful establishment of 3 commercial ET programs.…”

Developments of reproductive management and biotechnology in the pig

“…The need for surgical ET has certainly hampered the progress of bringing this method closer to implementation under field conditions. Multiple research groups have attempted to develop a nonsurgical ET procedure (Galvin et al, 1994;Hazeleger and Kemp 1994;Li et al, 1996;Yonemura et al, 1996;Martinez et al, 2004;Martinez et al, 2016).…”