078 Impact of breed and forage type on intake, performance, and residual feed intake of beef calves during the backgrounding period.

Forage quality, and possibly forage harvesting method, can impact calf performance during the backgrounding period. In addition, breed type may impact calf performance based on harvest method. Thirty Angus (n = 16, BW = 255.8 ± 9.7 kg) and Brangus (n = 14, BW = 231.8 ± 38.5 kg) ranch-of-origin steers from two locations were used to determine the effects of feeding annual ryegrass (Lolium multiflorum) hay or baleage on DMI, residual feed intake (RFI), and performance. Steers were stratified by initial BW and breed and fed a diet consisting of either hay (DM = 89.7%, CP = 12.4%, NDF = 69.4%, TDN = 56.9%) or baleage (DM = 51.2%, CP = 11.9%, NDF = 68.3%, TDN = 56.2%) in a 2 × 2 factorial arrangement. At weaning, steers were housed in individual pens (2.2 × 9.1 m) equipped with 2.2 m of linear bunk space for a 14 d adaption and 64 d feeding period. Individual feed intake was collected daily and used to calculate RFI for each steer as the difference between actual and expected feed intake calculated based on metabolic BW and ADG. Steer was the experimental unit. Two-day initial, weekly, and final BW were collected to determine BW gain and ADG. Data were analyzed using Proc GLM with breed and diet as fixed effects and initial BW as a covariate. There was no breed × diet interaction (P ≥ 0.40); therefore, all data were pooled for main effects. End BW, BW gain, and ADG tended to be greater (P = 0.05) for Angus compared with Brangus calves, respectively. In addition, DMI and RFI was lesser (P < 0.01) for Brangus (4.43 and -0.30 ± 0.09 kg, respectively) compared to Angus (5.32 and 0.26 ± 0.09 kg, respectively) calves. For diet effect, final BW, BW gain, and ADG was greater (P < 0.01) for calves consuming baleage compared to hay. Dry matter intake was also greater (P < 0.01) in calves consuming baleage (5.37 ± 0.09 kg) compared with hay (4.40 ± 0.09 kg) and RFI tended to be greater (P= 0.06) for calves consuming baleage (0.10 ± 0.08 kg) compared with hay (-0.14 ± 0.08 kg), respectively. Brangus calves consumed less forage, yielding lower gains in addition to a lower RFI. Feeding baleage of similar quality during the backgrounding period resulted in greater intake and animal performance.