Growth and accretion of energy and protein in the gravid uterus during late pregnancy in Holstein cows.

摘要: Multiparous Holstein cows (n = 18) were bred artificially to the same bull and then slaughtered at times ranging from 190 270 d postconception assess accretion of energy, protein, fat, ash by conceptus. Wet weights, dry concentrations CP, crude obtained for following: fetus, combined amniotic allantoic fluids, fetal membranes, cotyledons, caruncles, uterine tissues. Rates accumulation these components in gravid uterus (sum all contents) fetus described linear or quadratic equations. Estimated rates energy (i.e., conceptus) increased 567 kcal/d gestation 821 gestation; corresponding CP 62 117 g/d. These daily represent net protein requirements conceptus growth during late pregnancy mature cows. Conversion predicted metabolizable growth, using accepted efficiency factor .14, yielded estimates that consistent with current NRC recommendations. Factorial estimation absorbed is hampered lack precise information on which AA are deposited