Pearl Millet Cultivar and Seeding Method Effects on Forage Quality and Performance of Grazing Beef Heifers

Abstract

In a 2-yr study, yearling beef heifers grazed pastures of two pearl millet (Pennisetum glaucum [L.] R. Br.) cultivars (Tifleaf 1 [TL1] or Tifleaf 2 [TL2]) planted with two seeding methods (conventional drill at 25 lb seed/acre; or 3-ft rows at 5 lb seed/acre). Eight 2.0-acre pastures on Tifton sandy loam (fine-loamy, siliceous, thermic Plinthic Kandrudults) soil were used each year in the 2 × 2 × 2 factorial experiment. Four heifers (706 lb initial body weight) grazed continuously for 84 d on each pasture, beginning 4 and 3 June in respective years. Additional heifers were used to vary stocking rates in all pastures to maintain forage height at 18 to 25 in. Cultivar did not affect (P > 0.10) ADG or gain/acre (TL1 = 1.50; 477 lb vs TL2 = 1.46; 454 lb). Seeding method did not affect ADG or gain/acre (P > 0.10), but grazing dayslacre were higher for row than conventional drill (row = 847 vs drill = 751; P < 0.05). Heifer ADG and grazing days were affected by year, with higher ADG in 1992 than 1993 (1.64 vs 1.29 lb; P < 0.05), and more grazing days/acre in 1993 than 1992 (350 vs 297; P < 0.01). A seeding method by year interaction (P < 0.10) resulted in higher ADG and gain/acre for conventional drill than rows in 1992 when rainfall distribution was more favorable, and similar performance on rows and conventional drill in 1993 when rainfall distribution was less favorable. Esophageal steer pasture masticate in 1992 on d 77 had lower NDF for conventional drill than rows (27.3 vs 35.8%; P < 0.05), and IVDMD was higher for conventional drill than rows (70.8 vs 64.0%; P < 0.05). Seeding method affected forage quality and heifer performance, with rows being favored when rainfall was limited.