Comparison of grazing oat and pea crop residue versus feeding grass-legume hay on beef-cow performance, reproductive efficiency, and system cost1

Spring-calving nonlactating pregnant Angus (Bos taurus) cows (yr 1, n = 90, BW = 637.6 ± 5.8 kg; yr 2, n = 78, BW = 671.2 ± 8.1 kg; yr 3, n = 68, BW = 669.4 ± 6.6 kg) were managed in 1 of 3 replicated (n = 3) wintering systems: (i) grazing oat residue [OATG; TDN = 58.6, CP = 6.7 (% DM)] piles in field paddocks; (ii) grazing pea residue [PEAG; TDN = 50.9, CP = 11.1 (% DM)] piles in field paddocks; and (iii) drylot (DLPF) pen feeding grass-legume round bales [TDN = 54.5, CP = 10.4 (% DM)] in bale feeders. The study was conducted over 3 production cycles, and cows were allocated crop residue and bales on a 3-d basis to manage utilization and feed waste. Forage utilization was less (P < 0.05) in PEAG (33.4 ± 4.3%) and OATG (44.9 ± 5.9%) systems than in the DLPF (90.0 ± 1.63%) wintering system. Dry matter intake of cows varied (P < 0.05) among systems; cows consuming PEAG or OATG had less (P < 0.01) DMI compared with DLPF cows. Nutrient (CP, TDN) intake was greatest (P < 0.05) for DLPF cows and least for cows in the PEAG system. Cows grazing PEAG residue lost BW (11 kg) from d 1 to 20; however, BW change during the entire trial period (63 d) was positive (4 kg) for PEAG cows but less (P = 0.01) than OATG (27 kg) or DLPF (66 kg) cows. Calf birth weight was least (P = 0.03) for OATG cows than DLPF cows, 39 vs. 42 kg, respectively. On average, total costs for the OATG and PEAG winter feeding strategies were $0.77 and $0.59 cow/d less than the DLPF ($2.13 cow/d) system, respectively. Grazing crop residue for part of the winter feeding program of a cow has cost advantages over pen-feeding hay; however, environmental conditions (snowfall, temperature) dictate forage accessibility. Therefore, producers with access to crop residues should consider using this feed in a chaff-straw based ration along with adequate supplementation to ensure the nutritional needs of the cow are being met.