Effects of nutrition on productivity of March-calving beef cows and progeny when grazing corn residue or fed hay prepartum, and grazing subirrigated meadow or fed hay postpartum

Abstract

This study evaluated the effects of grazing corn residue prepartum and subirrigated meadow postpar- tum versus harvested meadow hay during both periods on cow pregnancy rates and calf feedlot performance. Crossbred March-calving cows (yr 1, n = 72; yr 2, n = 65; yr 3, n = 64) were used in a 2 × 2 factorial as part of a 3-yr study. From De- cember 1 to February 28 (prepartum), cows grazed corn residue (CPRE) or were fed 7.7% CP and 56.8% TDN hay (HPRE) ad libitum. From parturition to July 20, half were fed ad libitum hay (HPOST) and half grazed subirrigated meadow (MPOST). No interactions were present between pre- and postpartum treatments. Cows on HPRE had greater precalving and prebreeding BW and BCS (P < 0.01), whereas CPRE cows tended to have an earlier calving date (P = 0.07) and a greater percentage calving in the first 21 d (P = 0.07). Cows on MPOST had greater BW and BCS at prebreeding (P < 0.01) and weaning (P < 0.01) than HPOST cows. These differences were maintained until the following year pretreatment leading to greater overall BW and BCS (P < 0.02) in MPOST cows. Pregnancy rates were similar regardless of treatment (P > 0.50). Calves born to MPOST cows had greater BW at birth (P = 0.05), prebreeding (P < 0.01), and weaning (P < 0.01) and had greater ADG from birth to prebreeding (P = 0.01) and birth to weaning (P < 0.01) than HPOST calves. Steers from HPRE cows had a greater marbling score than CPRE steers (P = 0.02). Grazing corn residue or feeding hay prepartum and feeding hay or graz- ing subirrigated meadow postpartum affected BW and BCS during the pre- and postpartum periods of cows and calves. However, limited effects were detected on dam re- production.