Effect of defoliation interval on biomass yield and chemical composition of stylo ‘ CIAT 184’ ( S tylosanthes guianensis (Aubl.) Sw. var. guianensis )

Forage legumes are considered to have potential as supplementary feedstuffs for livestock (e.g. pigs) in smallholder systems in A sian countries, but forage management is crucial in order to obtain high feed quality. S tylo ‘ CIAT 184’ ( S tylosanthes guianensis (Aubl.) S w. var. guianensis ) was grown for two seasons in V ientiane, L ao PDR , and subjected to three defoliation frequency treatments: four harvests (S4, 4‐week intervals), three harvests (S3, 6‐week intervals), or one harvest (S1, end of each experimental period). Leaf and stem dry matter ( DM ) yield, leaf proportion ( DM basis) and chemical composition of the leaves, stems and forage (leaf + stem) were determined. Leaf DM yield was unaffected by treatments in 2007 (6–10 t ha −1 ). In 2008, treatments S4 and S3 had a higher leaf DM yield (mean 4 t ha −1 ) than treatment S1. Stem DM yield was highest in S1 in 2007, but did not differ between treatments in 2008. Leaf proportion did not differ between treatments S4 and S3 and was on average 55% and 60% in 2007 and 2008, respectively, while S1 had a lower leaf proportion in both years. Depending on defoliation frequency, the leaves contained 170–235 g CP kg −1 DM , which was much higher than the CP content of the stems (73–108 g kg −1 DM ) and forage (85–182 g kg −1 DM ). N eutral detergent fiber content of the leaves was 510–570 g kg −1 DM , which was lower than that of the stems (698–722 g kg −1 DM ) and forage (583–621 g kg −1 DM ). The total essential amino acid content of the leaves ranged from 45–50 g 16 g −1  N. It is concluded that the optimal defoliation interval of stylo ‘ CIAT 184’ for use as a protein feed resource for growing pigs is 4–6 weeks. However, the lysine content may not be adequate for optimal growth.