Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/28/2004
Publication Date: 2/8/2005
Citation: Ferrell, C.L. 2005. Maternal and fetal genotype influences on fetal growth [abstract]. Journal of Animal Science. 83(Suppl. 2):27.
Technical Abstract: Objectives are to review influences of maternal and fetal genotype on fetal growth and development. Brahman (Br) cows with Br or Charolais (C) fetuses and C cows with Br or C fetuses were used. Indwelling catheters were placed in a uterine artery, uterine vein, umbilical vein, fetal femoral artery, and fetal femoral vein at 220 ± 0.4 d after embryo transfer. Uterine and umbilical blood flows (L/min) and net uptakes of glucose, lactate, alpha-amino N, urea N, ammonia N, and estrone sulfate by the gravid uterus, fetus, and uteroplacenta were determined on 227 ± 0.4 d. Cows were killed on 232 ± 0.5 d or 271 ± 0.7 d. Weights of the fetus, fetal membranes, cotyledons, caruncles, and uterus were recorded as were weights of the fetal liver, heart, kidneys, spleen, lungs, stomach complex, intestines, and semitendinosus muscle. Data were analyzed by analysis of variance with breed of cow (CB), breed of fetus (FB), day of gestation (D), and all interactions were included in the model as fixed effects. Uterine blood flow in Br cows with Br (5.01) or C (4.66) fetuses was similar, but less (P<0.01) than in C cows with Br (7.14) or C (9.24) fetuses, which differed (P<0.01). Umbilical blood flows of C (3.78) were greater (P<0.01) than those of Br (2.29) fetuses. Fetal uptake of oxygen, glucose, and alpha-amino N, gravid uterine uptake of alpha-amino N, and uteroplacental uptake of glucose were greater for C than for Br fetuses. Gravid uterine oxygen uptake and uteroplacental lactate release were influenced by CB×FB. Fetal weights were influenced (P<0.01) by CB, FB, D, CB×D and tended (P=0.07) to be influenced by CB×FB×D. Caruncular weights were greater for C than for Br cows (P<0.05) or fetuses (P<0.01) and were greater (P<0.05) at 271 than at 232 d, but FB was the only significant source of variation in cotyledon weight, RNA, DNA, or protein. Results demonstrated that maternal uterine environment influences fetal growth and suggests those influences are mediated, in part, by growth and function of placentomal tissues and uterine blood flow.