Effects of harvest stage and re‐growth on yield, composition, ensilage and in vitro digestibility of new forage sorghum varieties

Abstract

The effect of growth stage and re-growth on the nutritional and ensilage characteristics of two new sorghum hybrids, BMR-101 and Silobuster, and one commercial variety, FS-5, was examined in this study. Varieties were sampled during the summer at the early heading (EH) stage and were harvested at the soft dough (SD) stage. Additional irrigation enabled autumn re-growth and a second harvest. Plants of FS-5 and BMR-101 were resistant to lodging at EH. However, BMR-101 and Silobuster suffered from high lodging at the SD stage of the summer harvest. Dry matter (DM) content of FS-5 and BMR-101 at EH was below 250 g kg −1 . DM yields of the varieties were similar at the summer harvest and higher than their respective re-growth cuts. Ensilage DM losses were moderate and similar across varieties. Hemicellulose of SD plants was partly solubilised and most of the water-soluble carbohydrate fermented, yielding lactic acid, ethanol and volatile fatty acids (VFA), and a pH < 4. In vitro DM digestibility of varieties was similar in summer silages, but lower in the respective re-growth silages of FS-5 and BMR-101, reflecting the higher content of neutral detergent fibre and lignin in the re-growth silages. The summer plus re-growth cumulative yields of digestible DM of the respective FS-5, Silobuster and BMR-101 silages were 14.7, 16.6 and 14.5 t ha −1 . The commercial variety, FS-5, may have some advantage over BMR-101 and Silobuster owing to its relative resistance to lodging in addition to its high yield and good ensilage properties.

Enhancing forage quality through appropriate nitrogen dose, seed rate and harvest stage, in sorghum cultivars grown in Pakistan

“…Plants approaching at succeeding stage from PB to 50% heading, showed an increasing trend of NDF, ADF and ADL. These results are in contrast to the finding of Atis et al (2012) and Miron et al (2006) who reported reduction in NDF and ADF contents in forage sorghum with delayed harvesting. However, negative relation of N application rate to NDF concentration was found in the present study, while Pholsen and Somsungnoen (2004) found no significant effect of N on NDF concentration.…”

“…() and Miron et al . () who reported reduction in NDF and ADF contents in forage sorghum with delayed harvesting. However, negative relation of N application rate to NDF concentration was found in the present study, while Pholsen and Somsungnoen () found no significant effect of N on NDF concentration.…”

Morphological fractions, chemical composition and in vitro fermentation characteristics of maize stover of five genotypes

“…On the other hand, previous studies showed that stem fraction contributed over 0.50 to whole-plant wheat straw (Ohlde et al, 1992;Tan et al, 1995). Furthermore, stem fraction comprised about 0.45 to 0.70 of sorghum stover, with the contribution of leaf blade to whole stover being only 0.18 to 0.30 (Miron et al, 2006). The previous results indicated that the nutritive value of cereal straws is dependent on the proportion of stem in whole plant.…”

Dynamic expression of the nutritive values in forage sorghum populations associated with white, green and brown midrid genotypes

“…Since BMR Sorghum mutations were induced and described by Porter et al (1978), the BMR traits have drawn much attention by the scientists all over the world because of the characteristics of lower lignin content and higher digestibility at harvest stage (Oliver et al, 2004;Miron et al, 2006;Marsalis et al, 2010;Beck et al, 2013). However, reviews on nutritive values of BMR traits had been only limited individual BMR gene and their isogenic sorghum, or several forage sorghum cultivars.…”