Time of transuterine migration and distribution of embryos in the pig

Abstract

The time of intrauterine migration and spacing of embryos was determined in 36 gilts with one oviduct occluded, and in 48 gilts with one ovary. Embryos could enter the uterus from one oviduct only. Uteri of seven pregnant gilts were examined on each of days 6, 7, 8, 9, 10, 11, 12, 13, snd 15 of gestation. Migration of embryos from one horn to the other usually occurred first on day 8 or 9. The uterus was occupied completely by day 15. Rate of migration and dlstribution of embryos was not affected by number of embryos, number of corpora lutea, or by uterine length. Uterinc length did not change betwccn days 6 and 15. Bilateral ovariectomy after breeding was associated with arrested growth of embryos, a decreased rate of embryo migration and a reduction in uterine length.Intrauterine migration of embryos is known to occur in many mammals (Boyd, Hamilton and Hammond, '44; Hafez, '64) and has been regarded as a means of equalizing the distribution of embryos in cases of disparity in the number of fertilized eggs from each ovary. Internal transuterine migration of embryos was first reported in the pig by Corner ('21a) and was confirmed by Warwick ('26), Kelly ('28), and Dxiuk, Polge, and Rowson ('64). Preliminary reports (Dhindsa and Dziuk, '65; Waite and Day, '65) have given some evidence of the stage of gestation at which migration occurs. A more detailed and definitive study would be useful in understanding the mechanisms of migration and distribution of embryos. The following study was conducted to determine the time of migration of embryos in the pig and the effect of varying their numbers on rate of migration and distribution. MATERIAIS AND METHODSNinety-one gilts of' Yorkshire, Duroc, or Yorkshire X Duroc breeding were used for the study. Gilts were tested for estrus daily in the presence of a boar, and were bred on the first day of estrus either by natural mating or by artificial insemination. The day after breeding was designated as day one. Gilts were identified individually by tattoo and were assigned arbitrarily to treatments on the day of breeding.Uterine surgery was done aseptically via midventral laparotomy, using general AXAT. REC , 159 323-330.

Implantation and Establishment of Pregnancy in the Pig

“…To establish and maintain pregnancy, pig blastocysts must fi rst migrate within and between the long horns of the bicornuate uterus. The classical studies of Dziuk and others (Dziuk et al 1964 ;Dhindsa et al 1967 ;Polge and Dziuk 1970 ) established that intra-and inter-uterine migration of blastocysts is initiated shortly after hatching from the zona pellucida and continues until the time of rapid trophoblast elongation on day 11-12 of gestation. Uterine migration is stimulated through conceptus estrogen and prostaglandin (PG) synthesis quite possibly through the induction of histamine release from the underlying endometrium (Pope et al 1982(Pope et al , 1986b and/or actions of lysophosphatidic acid (Seo et al 2012b ).…”

Unilateral Ovariectomy: Effect on Litter Size and Uterine Vessels in Mice

“…This indicates that mice with one ovary (group II) have the same number of fertilized ova as intact mice (group I). Similar compensatory behavior of the remaining ovary after unilateral ovariectomy has been reported previously in pigs by Brinkley el al., [3], D hindsa et al [6], and Dhindsa and Dziuk [5], in hamsters by Chatterjee and G reenwald [4], and in rabbits, rats, and mice by Johnson [10] and Biggers et al [2], In fact. Hartman [9] has shown overcompensation in the opossum; removal of one ovary leads to a three fold increase in weight of the surviving ovary, which ovulates on the average three times as many eggs as would each ovary of a normal opossum.…”

Placentation, maternal–fetal interface, and conceptus loss in swine

“…When allowed to enter the uterus from only one oviduct, porcine embryos migrate from one horn to the other by gd8 or gd9 and are completely spaced within the uterus by gd15 regardless of the 155 number of embryos or uterine size [37]. This migration is important to allow equal utilization of the available uterine resources; space and nutrients [30].…”