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Conceptus competition for uterine space: different strategies exhibited by the Meishan and Yorkshire pig.
J Anim Sci. 2002 May; 80(5):1311-6.JA

Abstract

Our laboratory has demonstrated that Yorkshire placentae increase in size and surface area during the final third of gestation. In contrast, Meishan placental size remains constant during late gestation, but the density of blood vessels at the placental-endometrial interface increases markedly. Preliminary observations from our laboratory suggest that if one of two adjacent Meishan fetuses dies, the placenta of the remaining Meishan conceptus fails to increase its length of implantation or its placental weight or surface area. In contrast, if one of two adjacent Yorkshire fetuses dies, the adjacent conceptus accelerates its placental growth. The objective of this experiment was to document that Yorkshire, but not Meishan, conceptuses accelerate placental growth when adjacent fetuses are experimentally destroyed on d 40 of gestation. Straightbred Meishan (n = 5) and Yorkshire (n = 5) females were laparotomized and one uterine horn was randomly assigned to receive fetal crushing (treated horn); the other uterine horn served as a within-animal control. In the treated horn, every other fetus was then crushed through the uterine wall and the animals were allowed to recover. On d 111, animals were killed, uteri were recovered, and fetal weight, crown-rump length (CRL), placental weight, implantation site length, and placental surface area were recorded. Although there were no statistically significant differences in fetal weight or CRL observed between treated or control horns of females of either breed, there was a tendency for the fetuses in the treated uterine horn to be longer and heavier in both breeds. There were no differences in placental weight, placental surface area, or implantation site length between conceptuses in Meishan treated and control horns, which averaged 173.8+/-6.4 g, 1,162.7+/-35.9 cm2, and 19.0+/-0.4 cm, respectively. In contrast, placental weight, placental surface area, and implantation site length were increased (P < 0.05) in Yorkshire treated horns compared to Yorkshire control horns (306.1+/-26.0 g, 1,835+/-93.9 cm2, and 33.4+/-1.5 cm vs 253.7+/-13.4 g, 1,474.3+/-50.4 cm2, and 27.2+/-0.8 cm; respectively). These data confirm that Yorkshire conceptuses, but not Meishan conceptuses, accelerate placental growth when adjacent littermates perish as late as d 40 of gestation. These data indicate that differences exist in the strategies employed by Meishan and Yorkshire conceptuses in the competition for nutrients during gestation.

Authors+Show Affiliations

Department of Animal Science, Iowa State University, Ames 50011, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

12019620

Citation

Vonnahme, K A., et al. "Conceptus Competition for Uterine Space: Different Strategies Exhibited By the Meishan and Yorkshire Pig." Journal of Animal Science, vol. 80, no. 5, 2002, pp. 1311-6.
Vonnahme KA, Wilson ME, Ford SP. Conceptus competition for uterine space: different strategies exhibited by the Meishan and Yorkshire pig. J Anim Sci. 2002;80(5):1311-6.
Vonnahme, K. A., Wilson, M. E., & Ford, S. P. (2002). Conceptus competition for uterine space: different strategies exhibited by the Meishan and Yorkshire pig. Journal of Animal Science, 80(5), 1311-6.
Vonnahme KA, Wilson ME, Ford SP. Conceptus Competition for Uterine Space: Different Strategies Exhibited By the Meishan and Yorkshire Pig. J Anim Sci. 2002;80(5):1311-6. PubMed PMID: 12019620.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Conceptus competition for uterine space: different strategies exhibited by the Meishan and Yorkshire pig. AU - Vonnahme,K A, AU - Wilson,M E, AU - Ford,S P, PY - 2002/5/22/pubmed PY - 2002/10/3/medline PY - 2002/5/22/entrez SP - 1311 EP - 6 JF - Journal of animal science JO - J Anim Sci VL - 80 IS - 5 N2 - Our laboratory has demonstrated that Yorkshire placentae increase in size and surface area during the final third of gestation. In contrast, Meishan placental size remains constant during late gestation, but the density of blood vessels at the placental-endometrial interface increases markedly. Preliminary observations from our laboratory suggest that if one of two adjacent Meishan fetuses dies, the placenta of the remaining Meishan conceptus fails to increase its length of implantation or its placental weight or surface area. In contrast, if one of two adjacent Yorkshire fetuses dies, the adjacent conceptus accelerates its placental growth. The objective of this experiment was to document that Yorkshire, but not Meishan, conceptuses accelerate placental growth when adjacent fetuses are experimentally destroyed on d 40 of gestation. Straightbred Meishan (n = 5) and Yorkshire (n = 5) females were laparotomized and one uterine horn was randomly assigned to receive fetal crushing (treated horn); the other uterine horn served as a within-animal control. In the treated horn, every other fetus was then crushed through the uterine wall and the animals were allowed to recover. On d 111, animals were killed, uteri were recovered, and fetal weight, crown-rump length (CRL), placental weight, implantation site length, and placental surface area were recorded. Although there were no statistically significant differences in fetal weight or CRL observed between treated or control horns of females of either breed, there was a tendency for the fetuses in the treated uterine horn to be longer and heavier in both breeds. There were no differences in placental weight, placental surface area, or implantation site length between conceptuses in Meishan treated and control horns, which averaged 173.8+/-6.4 g, 1,162.7+/-35.9 cm2, and 19.0+/-0.4 cm, respectively. In contrast, placental weight, placental surface area, and implantation site length were increased (P < 0.05) in Yorkshire treated horns compared to Yorkshire control horns (306.1+/-26.0 g, 1,835+/-93.9 cm2, and 33.4+/-1.5 cm vs 253.7+/-13.4 g, 1,474.3+/-50.4 cm2, and 27.2+/-0.8 cm; respectively). These data confirm that Yorkshire conceptuses, but not Meishan conceptuses, accelerate placental growth when adjacent littermates perish as late as d 40 of gestation. These data indicate that differences exist in the strategies employed by Meishan and Yorkshire conceptuses in the competition for nutrients during gestation. SN - 0021-8812 UR - https://www.unboundmedicine.com/medline/citation/12019620/Conceptus_competition_for_uterine_space:_different_strategies_exhibited_by_the_Meishan_and_Yorkshire_pig_ L2 - https://academic.oup.com/jas/article-lookup/doi/10.2527/2002.8051311x DB - PRIME DP - Unbound Medicine ER -