Supplementation with multinutrient blocks of post-weaning cattle grazing forages or sorghum stubble

Abstract

Two experiments were carried out in order to evaluate the effect of supplementation with multinutrient blocks (BM) in recently weaned dual-purpose cattle that grazed forages or sorghum stubble during the rainy and dry seasons, respectively. A completely randomized design was used in each 84-day trial to compare treatment with BM against another supplemented with a mineral mixture (MM). The main constituents of the block were molasses 35%, sesame flour 32.5% and urea 10%, and had 51% crude protein (CP). 30 animals were used in each station, initially with 116.9 and 102.3 kg of average weight and 7 and 9 months of age. Two 10 to 12 ha paddocks were grazed continuously in each season, rotating between treatments every two weeks. In the rainy and dry seasons, the biomass present was higher than 2985 and 2026 kg DM / ha and the CP contents varied from 12.1 to 4.6% and from 3.4 to 2.3%, respectively. The average daily gain in the MM and BM treatments was 0.65 and 0.71 kg in the rainy season and 0.13 and 0.25 kg in the dry season (P <0.01), with average BM consumption of 81 and 241g DM / 100 kg LW , respectively. The increased responses to BM during the dry season were associated with a lower CP content in sorghum stubble.