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This Article Full Text (PDF) All Versions of this Article: jas.2008-1672v1 87/6/1950    most recent 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 Google Scholar Google Scholar Articles by Long, N. M. Articles by Ford, S. P. Search for Related Content PubMed PubMed Citation Articles by Long, N. M. Articles by Ford, S. P.

Effects of early gestational undernutrition on fetal growth, organ development, and placentomal composition in the bovine

N. M. Long^*,, K. A. Vonnahme^*,, B. W. Hess^*,, P. W. Nathanielsz^*, and S. P. Ford^*,

^* The Center for the Study of Fetal Programming, Laramie, WY 82071 , Department of Animal Science, University of Wyoming, Laramie, WY 82071 , Department of Animal Sciences, Fargo, ND 58105 Department of Obstetrics and Gynecology, University of Texas Health Sciences Center, San Antonio 78299

spford{at}uwyo.edu

Abstract

Fetal intra-uterine growth restriction (IUGR) is known to negatively impact offspring health postnatally. This study evaluated the impacts of early gestational undernutrition followed by realimentation on bovine fetal and placental growth. Thirty multiparous beef cows bred to a single sire and gestating female fetuses were fed either to meet NRC recommendations (control; C; n = 15) or fed below NRC recommendations (68.1% of NE_m and 86.7% of MP recommendations; nutrient restricted, NR; n = 15) from d 30 to 125 of gestation. On d 125 of gestation, 10 C and 10 NR cows were necropsied. The remaining 5 NR cows were realimented to achieve similar BW and BCS with the remaining 5 C cows by d 190 of gestation; both groups were necropsied at d 245 of gestation. Fetal weight at d 125 of gestation was 948 ± 14 g (n = 10) for C cows; however, fetal weights of NR cows fell into 2 distinct groups: NR non IUGR cows had fetal weights similar to C cows (974 ± 20 g, n = 6), while fetal weights of NR IUGR cows were reduced (773 ± 23 g, n = 4; P < 0.01). Fetal brain weight as a percentage of fetal weight was increased (~11%; P < 0.01) in the NR IUGR fetuses compared to fetuses from the other 2 groups, which were similar. Fetal heart weight as a percentage of fetal weight also tended to be increased (~10%; P = 0.08) in NR IUGR fetuses compared to C fetuses. Nutrient restricted IUGR cows exhibited reduced (P < 0.01) cotyledonary weights compared to NR non IUGR and C cows, which were similar (192 ± 27 vs. 309 ± 22, and 337 ± 17g, respectively). Total placentome surface area also tended to be reduced (P = 0.07) in NR IUGR cows compared to NR non IUGR and C cows, which again were similar (685.0 ± 45.6 vs. 828.7 ± 37.2 and 790.7 ± 28.9 mm², respectively). On d 245 of gestation, fetal weights and caruncle weight were similar for NR and C cows; cotyledonary weights, however, were reduced in NR vs. C cows (1,430 ± 133 vs 2,137 ± 133g, P < 0.01). Decreased fetal growth in NR IUGR cows on d 125 of gestation was associated with decreased cotyledonary weights and reduced placentomal surface areas. The return of NR cows to a BW and BCS similar to that of C cows through realimentation beginning on d 126 resulted in similar fetal weights of NR and C cows by d 245 of gestation. Thus, a bout of fetal IUGR may go undetected if cows undernourished during early gestation receive feed supplementation in the second half of gestation to assure normal birth weight.

Key Words: cow • fetal growth • maternal undernutrition • placentome development