Estimation of Optimum Utilization of Ruminant Feed Resources on Tropical Dry-Land during Dry and Rainy Seasons

This study aimed to estimate the optimum utilization of ruminant feed resources in tropical dry-land during dry and rainy seasons. Data concerning feed availability and quality were collected from Gunungkidul Regency of Indonesia over two seasons: the dry and rainy seasons. The JAVA program, the model, was used to estimate the availability of feed for ruminants associated with mean live weight gain (MLWG) and total live weight production (TLWP). The results showed that the maximum production in the dry season was obtained when 18% dry matter (DM) was used (MLWG 0.33 kg/animal unit (AU)/day, herd size (HS) 197 AU, and TLWP 11.94 tons/season), or in the rainy season, when 46% DM was used (MLWG 0.18 kg/AU/day, HS 1116 AU, and TLWP 37.22 tons/season). Furthermore, when only 100% was used, it could feed a maximum of 1500 AU and 2968 AU in the dry and rainy seasons, respectively. Without the transfer of feed from one season to another, a constant number, 350 AU, was obtained for HS, with a maximum TLWP of 19.16 tons/year. On the other hand, when the feed was kept constant at 34% dry matter (DM), a maximum TLWP obtained was 32.32 tons/year which is enough 420 and 820 animal units in the dry and rainy season, respectively. It was concluded that to obtain maximum TLWP in each season, only 14.5% to 46% of available DM feed should be used, as most of the available feed was of very low qualit