Effect of backgrounding systems on winter and finishing performance, forage intake, carcass characteristics of beef calves and economic analysis

Abstract

A 2-year winter grazing and feedlot finishing trial (Exp 1) and subsequent in-situ nutrient disappearance study (Exp 2) were conducted to evaluate the effects of swath grazing forage barley (Hordeum vulgare, cv. Ranger) or foxtail millet (Setaria italica, cv. Golden German) compared to grass-legume hay fed in drylot on calf performance. In trial1 in each of 2 years, 120 spring born Angus calves (60 steers, 60 heifers) were fall weaned, stratified by weight, allocated into 20-head groups then assigned randomly to one of the three replicated (n=2) backgrounding (BG) systems. Backgrounding systems were (i) swath graze barley (BR); (ii) swath graze millet (ML); and (iii) bunk fed ground hay drylot (DL). Swath grazed calves were limit fed in 8 ha paddocks with 3 d grazing periods, using electric fencing for 96 d each year. All groups received a pelleted supplement at 0.62% BW. Calves were weighed at start, every 21 d and end of background period. Following the BG period, calves were placed in feedlot, separated by sex and BG treatment and fed a similar finishing ration and harvested at a targeted endpoint of 12 mm back fat. Forage samples collected every 21 d were analyzed for DM, CP and digestible energy (DE) and change in nutritive quality over the grazing period. DE content was greatest (P