|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
ANIMAL GROWTH, PHYSIOLOGY, AND REPRODUCTION |




,2
* The Center for the Study of Fetal Programming, Laramie, WY 82071;
and
Department of Animal Science, University of Wyoming, Laramie 82071;
and
Department of Animal Sciences, North Dakota State University, Fargo 58105; and
Department of Obstetrics and Gynecology, University of Texas Health Sciences Center, San Antonio 78299
2 Corresponding author: spford{at}uwyo.edu
Fetal intrauterine growth restriction (IUGR) is known to negatively affect 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 to meet NRC recommendations (control; n = 15) or fed below NRC recommendations (68.1% of NEm and 86.7% of MP recommendations; nutrient restricted, NR; n = 15) from d 30 to 125 of gestation. On d 125 of gestation, 10 control and 10 NR cows were necropsied. The remaining 5 NR cows were realimented to achieve similar BW and BCS with the remaining 5 control 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 control cows; however, fetal weights of NR cows fell into 2 distinct groups: NR non-IUGR cows had fetal weights similar to control cows (974 ± 20 g, n = 6), whereas 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 with 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 with control fetuses. Nutrient-restricted IUGR cows exhibited reduced (P < 0.01) cotyledonary weights compared with NR non-IUGR and control cows, which were similar (192 ± 27 vs. 309 ± 22, and 337 ± 17 g, respectively). Total placentome surface area also tended to be reduced (P = 0.07) in NR IUGR cows compared with NR non-IUGR and control 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 control cows; cotyledonary weights, however, were reduced in NR vs. control cows (1,430 ± 133 vs. 2,137 ± 133 g, 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 control cows through realimentation beginning on d 126 resulted in similar fetal weights of NR and control 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
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |