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RESEARCH ARTICLE

Maternal endometrial oedema may increase perinatal mortality of cloned and transgenic piglets

M. Schmidt A G , K. D. Winter B , V. Dantzer C , J. Li D , P. M. Kragh D , Y. Du D F , L. Lin D F , Y. Liu D , G. Vajta D , P. T. Sangild E , H. Callesen D and J. S. Agerholm A
+ Author Affiliations
- Author Affiliations

A Department of Large Animal Sciences, Section for Veterinary Reproduction and Obstetrics, Faculty of Life Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark.

B Danish Agriculture & Food Council, Vinkelvej 11, DK-8620 Kjellerup, Denmark.

C Department of Basic Animal and Veterinary Science, Section for Anatomy and Cell Biology, Faculty of Life Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark.

D Genetics and Biotechnology, Faculty of Agricultural Sciences, Aarhus University, DK-8830 Tjele, Denmark.

E Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark.

F Present address: BGI/HuaDa Shenzhen, 518000 Shenzhen, China.

G Corresponding author. Email: mhs@life.ku.dk

Reproduction, Fertility and Development 23(5) 645-653 https://doi.org/10.1071/RD10220
Submitted: 7 September 2010  Accepted: 2 February 2011   Published: 5 May 2011

Abstract

The perinatal mortality of cloned animals is a well-known problem. In the present retrospective study, we report on mortality of cloned transgenic or non-transgenic piglets produced as part of several investigations. Large White (LW) sows (n = 105) received hand-made cloned LW or minipig blastocysts and delivered either spontaneously or after prostaglandin induction followed by either Caesarean section or vaginal birth. The overall pregnancy rate was 62%, with 26% of pregnancies terminating before term. This resulted in 48 deliveries. The terminated pregnancies consisted of 12 abortions that occurred at 35 ± 2 days gestation and five sows that went to term without returning to heat and then by surgery showed the uterus without fetal content. The gestation length was for sows with LW piglets that delivered by Caesarean section or vaginally was 115.7 ± 0.3 and 117.6 ± 0.4 days, respectively. In sows with minipiglets, the gestation length for those delivered by Caesarean section or vaginally 114.4 ± 0.2 and 115.5 ± 0.3 days, respectively. Of the 34 sows that delivered vaginally, 28 gave birth after induction, whereas 6 farrowed spontaneously. Of the 14 sows that delivered after Caesarean section and in the five empty sows, the endometrium and placenta showed severe oedema. Piglet mortality following vaginal delivery was higher than after Caesarean section (31% v. 10%, respectively; P < 0.001). When vaginal delivery occurred spontaneously, the stillborn rate was greater than after induced delivery (56% v. 24%, respectively; P < 0.0001). Internal organ weights were recorded for seven cloned LW piglets and six normal piglets. The relative weight of the heart, liver, kidneys and small intestine was found to be reduced in the cloned piglets (P < 0.05). The present study demonstrates extensive endometrial oedema in sows pregnant with cloned and transgenic piglets, as well as in empty recipients, at term. The growth of certain organs in some of the cloned piglets was reduced and the rate of stillborn piglets was greater in cloned and transgenic piglets delivered vaginally, possibly because of oedema of the fetal–maternal interface.

Additional keywords: birth method, endometrium, organ weight, placenta, stillbirth, survival.


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