Evaluation of BMR Forage Systems for Beef Cattle Performance in Mississippi.

Conventional warm-season annual grasses have been utilized as a forage source for livestock. Forage crops with the BMR trait can improve nutritive value and increase animal performance. The objective of the study was to determine the influence of BRM cultivars in forage production, nutritive value, and animal performance. The study was conducted at Mississippi State University in the summer of 2018 in a Savannah Fine Sandy loam soil. The experimental design was a randomized complete block replicated three times. Twelve paddocks averaging 0.73 ac per paddock (3 paddocks/treatment) were planted in forage sorghum (FSG-115-Brachytic-Dwarf-BMR6-Hybrid), sorghum-sudangrasses (FSG-214-BMR6-Hybrid and Green Grazer V), and pearl Millet (FSG-315-Dwarf-BMR) at a seeding rate of 25 PLS/ac using a conventional drill. All paddocks were stocked with 2 yearly crossbred steers per paddock. All paddocks were adjusted for pH, P, and K based on soil test recommendations and fertilized with 50 lb N/ac one week after seedling emergence. Forage allowance was maintained at 1 lb/lb steer BW using a put and take system. Six random forage samples were collected from each paddock to determine biomass and nutritive value. Paddocks were grazed only for 28 days due to armyworms that contributed to decreased mean forage mass, forage allowance, and shorter grazing season. Mean forage biomass was 3,368 ± 1,095 lb DM/ac, where pearl millet FSG2315 had lower biomass (2725 lb DM/ac) compared to the other cultivars. On the hand, FGS315 had greater LAI compared to the rest of the cultivars. There were significant differences among cultivars in nutritive value for CP (P = 0.0029), ADF (P = 0.0002), NDF (P < 0.0001), and IVTDMD48 (P = 0.0188), respectively. Forage sorghum and pearl millet had greater ADG compared to the rest of the cultivars while FSG115 had greater mean gain per acre compared to the rest of the cultivars.