J. Anim Sci., doi: 10.2527/jas.2006-805
©Copyright, 2007, The American Society of Animal Science
Effect of Early Gestational Undernutrition on Angiogenic Factor Expression and Vascularity in the Bovine Placentome
K. A. Vonnahme 1,
M. J. Zhu 2,
P. P. Borowicz 3,
T. W. Geary 4,
B. W. Hess 5,
L. P. Reynolds 6,
J. S. Caton 7,
W. J. Means 2,
S. P. Ford 8*
1 North Dakota State University, rm 178 Hultz, Fargo, 58105, United States
2 Animal Science, University of Wyoming, Laramie, Wyoming, United States
3 North Dakota State University, Fargo, North Dakota, United States
4 Fort Keogh LARRL, USDA-ARS, Miles City, Montana, United States
5 Department of Animal Science, University of Wyoming, Laramie, Wyoming, United States
6 Animal & Range Sciences, North Dakota State University, Fargo, North Dakota, United States
7 Animal and Range Sciences, NDSU, Fargo, North Dakota, United States
8 Animal Science, University of Wyoming, Laramie , Wyoming, United States; , United States
* To whom correspondence should be addressed. E-mail: spford{at}uwyo.edu.
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Abstract |
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The effect of early gestation maternal undernutrition followed by re-alimentation on placentomal vascular growth and angiogenic factor expression was determined in multiparous beef cows bred to the same bull. Cows gestating only female fetuses (n = 30) were fed in equal numbers to either meet NRC requirements (Control) or fed below NRC requirements to lose BW (nutrient restricted; NR) from d 30 to d 125 of gestation. Following slaughter on d 125 of gestation, 10 Control and 10 NR cows were necropsied. The remaining NR cows (n = 5) were then fed to achieve a BCS equal to their control contemporaries (n = 5) by d 220 of gestation. All cows were fed the control diet from d 220 until d 250 of gestation, when the remaining Control and NR cows were slaughtered and necropsied. At necropsy, placentomes were fixed via perfusion of the caruncular and cotyledonary arteries to determine capillary vascular density. Cotyledonary (fetal placental) and caruncular (maternal placental) tissues also were snap frozen in liquid nitrogen, and mRNA concentrations of vascular endothelial growth factor and its two specific receptors Flt-1 and KDR, as well as placental growth factor (PlGF) were determined. There was no effect of diet or day of gestation on the percentage of proliferating caruncular cells. While diet did not impact cotyledonary cellular proliferation, there was an increase (P < 0.05) in the percentage of proliferating cells on d 250 compared with d 125 of gestation. Nutrient restriction from d 30 to d 125 increased (P 
0.10) placental mRNA concentrations of PlGF and Flt-1; however, there was no alteration in vascularity. By d 250 of gestation, NR cows had increased (P < 0.05) caruncular capillary surface density and decreased (P < 0.05) cotyledonary capillary area density, capillary number density, and capillary surface density compared to Control cows. Although NR had little effect on placental vascularity by d 125, upon re-alimentation, alterations in vascularity became apparent by d 250 of gestation, suggesting a "placental programming" effect.
Key Words:
Cattle, placental efficiency, pregnancy
