Pre-Conditioning Beef Calves with High-Moisture Stored Forages or Hay and Co-Product Feeds.

A 45-d backgrounding study was conducted at the E.V. Smith Research Center in Shorter, AL to determine animal performance differences of pre-conditioned beef calves fed annual ryegrass (Lolium multiflorum) baleage, bermudagrass (Cynodon dactylon) hay, or corn (Zea mays) silage-based diets. Annual ryegrass (cv. Marshall) was harvested for baleage on 22 Apr 2015 at the late boot stage of maturity. The forage was allowed to wilt for 48 h until it achieved 60% moisture, baled and wrapped. Tifton 85 bermudagrass used for the study was harvested at a 4 to 5 wk interval in early summer 2015. Corn silage was harvested at the full dent stage of maturity on 15 Jul 2015, chopped, and stored until the initiation of the feeding trial. Forage concentrations of CP, ADF, and NDF (% DM) were 11.3, 35.6, and 57.2 for annual ryegrass baleage, 13.5, 35.8, and 63.9 for bermudagrass hay, and 5.8, 23.6, and 41.0 for corn silage, respectively. Based on forage quality, calves were supplemented with an energy-protein based ration (50:50 soybean hulls and corn gluten feed for baleage and hay treatments, and 85% corn, 15% cottonseed meal mix for corn silage treatments) to target 0.9 kg/day ADG according to NRC (2000) recommendations. The 45-d background trial began on 9 September 2015 after animals were sorted and acclimated to the diets. 108 weaned calves [heifers (n = 54; mean initial BW 283 kg) and steers (n = 54; mean initial BW 284 kg)] were placed into nine pens (n = 12/pen, 3 pens/treatment). Sex was distributed evenly across treatments. Animals were weighed on d 0, 22, and 44, and the study concluded on 23 October 2015. Animal performance measures were analyzed using PROC Mixed in SAS 9.4 as a completely randomized design, and pen was the experimental unit. Mean initial and final BW of the animals did not differ (P = 0.50 and P = 0.99, respectively) across treatments. Average daily gain for annual ryegrass baleage, bermudagrass hay, and corn silagebased diets were 0.61 kg/day, 0.72 kg/day, and 0.72 kg/day, respectively, and did not differ across treatments (P = 0.57). Based on these results, these forage options achieved a similar level of gain when supplemented for preconditioning beef calves. However, an economic analysis is needed to determine feasibility and potential break-even costs for using these options in beef operations. [ABSTRACT FROM AUTHOR]