Effect of planting pattern of forage sorghum on forage productivity and heifer performance during finishing phase

Abstract

This study aimed to assess the effect of sorghum planting patterns on forage response and performance of beef heifers at finishing phase. The experimental period lasted 84 days; treatments consisted of the combination of two interrow spacings (22 and 44 cm) and two sorghum-sowing rates (12 and 24 kg ha?1). Beef heifers, at finishing phase, with initial age of 15 months (± 2.3 months) and average body weight of 262 kg (± 37.95 kg), continuously grazed forage. The experimental design was completely randomized in a 2 × 2 factorial scheme with three repetitions per area. The different planting patterns did not affect (P > 0.05) dry matter production (5,447.78 kg DM ha?1) and accumulation rate (58.47 kg DM ha?1 day?1). Forage accumulation rate, leaf mass, forage mass, leaf supply and forage supply were influenced (P < 0.05) by time. Similar behavior was observed for stocking rate, weight gain per area unit and daily weight gain, with values of 1,172.32 kg of liveweight ha?1, 312.31 kg ha?1; 0.891 kg day?1, respectively. Animal performance had no effect (P > 0.05) from planting patterns, with nearly 4.04 mm of subcutaneous fat thickness and final weight of 330.36 kg. Animal body development showed no significant differences (P > 0.05), with values for length, heart girth and hip height of 132.01, 163.75 and 126.75 cm, respectively. The weight to average height ratio between planting patterns was 2.67 kg cm?1.