Effects of Total Mixed Rations Containing Treated or Untreated Soybean Meal on the Energy Utilization of Kacang Goats

Abstract

Background and Objective: There have been many efforts to improve the low productivity of Kacang goats. Feeding a total mixed ration (TMR) containing sources of energy and protein could improve the performance of the goat. Soybean meal is one of the protein sources that are palatable but highly degradable in the rumen, therefore, it was treated with formaldehyde. The aim of this study was to evaluate the energy utilization, volatile fatty acids (VFAs) and acetate-propionate acid (A/P) ratio of Kacang goats fed TMR diets containing different treatments of soybean meal. Methodology: Fourteen yearling Kacang bucks, weighing 17.6±1.2 kg, were arranged in a completely randomized design consisting of 3 different treatments that included an SBM control (n = 5): Untreated SBM, SBM50 (n = 5): 50% untreated SBM+50% formaldehyde-protected SBM and SBM100 (n = 4): 100% formaldehyde-protected SBM. The TMR consisted of 30% Pennisetum purpureum, 30% gliricidia leaves, 19.2% cassava waste product, 13.8% wheat bran, 7% SBM and 1% mineral mix that were mixed and resulted in 14-15% crude protein and 56-60% TDN. The goats were weighed weekly over 70 days and the average daily gain (ADG) was calculated using linear regression. Data were analyzed by an analysis of variance using the SPSS statistics software version 19. Results: The energy intake and digestible energy (DE) of the SBM control group (13.0 MJ and 7.7 MJ, respectively) were higher than those of the SBM50 group (10.2 MJ and 5.8 MJ, respectively) but they were relatively similar to the SBM100 group (11.3 MJ and 6.7 MJ, respectively). The energy conversion ratio (energy intake, DE and metabolizable energy [ME]) also had the same pattern. Digestible energy (% energy intake), faecal production, urine production, methane energy loss (MJ) and ME were similar between the treatments. Intake, digested and metabolizable energy (MJ kg^–1 BW^0.75) were also the same between the treatments. Total VFA and the A/P ratio before feeding were also similar between the treatments. In fact, the A/P ratio of the SBM control at 3 h and 6 h was higher than that of SBM50 but it was relatively similar to SBM100. Conclusion: Energy utilization of untreated SBM was better than that of 50% formaldehyde-protected SBM but it was similar to that of SBM100. The control group had an A/P ratio that was higher than the SBM50 group. In fact, total VFA was similar between the treatments.