HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Echternkamp, S. E. Articles by Ford, S. P. Search for Related Content PubMed PubMed Citation Articles by Echternkamp, S. E. Articles by Ford, S. P.

Increased vascular endothelial growth factor and pregnancy-associated glycoproteins, but not insulin-like growth factor-I, in maternal blood of cows gestating twin fetuses^1,2

S. E. Echternkamp^*,3, K. A. Vonnahme^,4, J. A. Green and S. P. Ford

^* USDA-ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166; and Department of Animal Sciences, University of Wyoming, Laramie 82071-3684; and Division of Animal Sciences, University of Missouri, Columbia 65211

³ Corresponding author: echternkamp{at}email.marc.usda.gov

Differences in placental mass and vascularity exist between cows gestating single vs. multiple fetuses. Therefore, the association between fetal number and placental development or function was assessed by comparing concentrations of vascular endothelial growth factor (VEGF), pregnancy-associated glycoproteins (PAG), IGF-I, and progesterone in the maternal blood of cattle selected for twin births and gestating 1 (n = 23) vs. 2 (n = 17) fetuses. Samples of jugular venous blood were collected serially at a mean of 57, 121, 192, and 234 d (range within groups was 20 d) after AI. Plasma concentrations of VEGF, IGF-I, and progesterone were measured by double-antibody RIA, and of PAG by an indirect sandwich ELISA. Concentrations of VEGF and progesterone were greater (P < 0.05) in dams with twin vs. single fetuses. Maternal VEGF concentrations did not differ among collection times, but progesterone concentrations increased (P < 0.01) between d 192 and 234. Conversely, PAG concentrations were low at d 57 and 121 and did not differ between dams carrying singles or twins. However, the subsequent increase (P < 0.01) in PAG was greater in dams with twins, resulting in greater (P < 0.01) PAG concentrations for dams with twins at d 192 and 234 (type of birth x time; P < 0.01). Maternal IGF-I concentrations were unaffected by fetal number. Because corpora lutea persisted for the duration of the evaluation period, maternal progesterone concentrations were likely related to the number of corpora lutea rather than the number of fetuses. It is postulated that the greater PAG and VEGF concentrations in the blood of dams gestating twins are the result of a larger uteroplacental mass, including increased numbers of binucleate cells and increased angiogenesis and vasculogenesis associated with a twin pregnancy. Although PAG and VEGF were elevated in dams gestating twins, variability within and among birth groups limits the use of PAG or VEGF measurements for the diagnosis of twins.

Key Words: blood • cattle • gestation • pregnancy-associated glycoprotein • twin • vascular endothelial growth factor

This article has been cited by other articles:

				S. E. Echternkamp, R. M. Thallman, R. A. Cushman, M. F. Allan, and K. E. Gregory Increased calf production in cattle selected for twin ovulations J Anim Sci, December 1, 2007; 85(12): 3239 - 3248. [Abstract] [Full Text] [PDF]

				A. B. Dixon, M. Knights, J. L. Winkler, D. J. Marsh, J. L. Pate, M. E. Wilson, R. A. Dailey, G. Seidel, and E. K. Inskeep Patterns of late embryonic and fetal mortality and association with several factors in sheep J Anim Sci, May 1, 2007; 85(5): 1274 - 1284. [Abstract] [Full Text] [PDF]