107 EARLY EMBRYONIC SURVIVAL IN THE PIG IS HIGHER THAN CONVENTIONALLY REPORTED
E. Østrup A , M. Vejlsted A , M. B. Nielsen B , M. T. Madsen B and P. Maddox-Hyttel AA University of Copenhagen, Copenhagen, Denmark;
B Danish Pig Production, Copenhagen, Denmark
Reproduction, Fertility and Development 21(1) 153-154 https://doi.org/10.1071/RDv21n1Ab107
Published: 9 December 2008
Abstract
It is generally accepted that 30% of the embryos in a porcine litter die within the first 40 days of pregnancy (Pope WP and First NL 1985 Theriogenology 23, 91–105). The aim of the study was to investigate the dynamics of embryonic mortality from the 2nd to the 7th week of pregnancy in a homogeneous pig population in order to test whether this dogma holds true. A total of 141 pregnant Danish Landrace × Yorkshire gilts were divided into three groups dependent on gestational length: Group 1 (Days 9 to 24 post insemination (p.i.)): At Days 9 to 18 p.i., embryos were collected by flushing the uterine horns with PBS containing 1% serum. At Days 19 to 24, embryos were identified in situ by opening of the horns along the anti-mesometrial side. All embryos were staged according to the morphological appearance of embryo proper. Pre-somite stage embryos were categorized as either: Hatched blastocysts, pre-streak 1, pre-streak 2, primitive streak, or neural groove stage embryos (Vejlsted M et al. 2006 Mol. Reprod. Dev. 73, 709–718). Somite stage embryos were staged according to the number of somites. All embryos in Group 2 (Days 24.5 to 33 p.i.) and Group 3 (Days 40.5 to 47 p.i.) were identified in situ by opening the uterine horns as described above. The localization in the uterus and the Crown Rump Length (CRL) was recorded for all embryos in these groups. The average embryo recovery rate, (i.e. the ratio between the numbers of recovered embryos and the CL numbers) was 82%. Moreover, there were no significant differences between the groups with respect to the embryo recovery rate, signaling the absence of continued embryonic mortality. No significant correlations were obtained between the location of the embryos in the uterus and the CRL (only measured for Groups 2 and 3). Our data indicate that (1) the level of embryonic mortality was less than 10 to 15% and (2) there was no continued embryonic mortality occurring between Days 9 to 47 p.i. This is in great contrast to previous reports. Furthermore, there is no evidence that the location in the uterine horn has any influence on the embryonic development.
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The Danish Research Council for Technology and Production Sciences.
