Title: Level of maternal winter supplement and feed restriction during postweaning development influences circulating concentrations of IGF-I in heifers during the peripartum and rebreeding period. Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2010
Publication Date: July 15, 2010
Citation: Roberts, A.J., Waterman, R.C., Geary, T.W., Alexander, L.J., MacNeil, M.D. 2010. Level of maternal winter supplement and feed restriction during postweaning development influences circulating concentrations of IGF-I in heifers during the peripartum and rebreeding period. Western Section American Society of Animal Science Abstract 88, E-Suppl. 2:769. Abstract #852. Interpretive Summary: abstract only
Technical Abstract: Objective of this research was to evaluate effects of 2 levels of supplemental feed provided to cows during late gestation and 2 levels of feed provided to their daughters during postweaning development on circulating concentrations of IGF-I in the daughters before calving, after calving and before breeding. Heifers were produced over a 3-yr period from dams that were fed levels of harvested feed from mid and late gestation (Dec to March) that were expected to provide marginal (MARG) or adequate (ADEQ) nutrition while grazing dormant winter forage through this period. After weaning, heifers were fed to appetite (CON) or restricted (REST) to 80 % of that consumed by CON on common BW basis during a 140-d period ending 1-mo before breeding. Heifers were managed together through breeding to Dec when they were separated so CON could be fed like ADEQ cows and REST could be fed like MARG cows up to 2 to 3-wk before start of calving in March. Concentrations of IGF-I (determined by RIA) in serum samples (n = 828) obtained 8 to 12-d before start of calving, 2 to 4-wk after calving and 0 to 18-d before to start of breeding were analyzed by the MIXED procedure of SAS using a model for repeated measures. Concentrations of IGF-I were influenced by interaction of dam and heifer treatments, being greater (P < 0.05) in CON heifers from ADEQ or MARG fed dams and REST heifers from MARG dams than in REST heifers from ADEQ dams. Concentrations of IGF-I were greater (P = 0.05) in heifers that gestated male than female calves, and in heifers that subsequently became pregnant than those that did not (P < 0.001). Results provide support that the dietary treatments imposed on cows resulted in a uterine programming effect in their heifers, as was evident by differences in circulating concentrations of IGF-I in heifers that were restricted fed during postweaning development.