Effects of Substituting Cassava Pulp with Broken Rice and Cassava Chips in Crossbred Holstein Diets: Rumen Fermentation, Enteric Methane Emission, and Energy Utilization.

This study evaluates the effects of substituting cassava pulp with broken rice and cassava chips in the total mixed ration silage diets of beef cattle on feed composition, ensiling quality, digestibility, and energy utilization. Fifteen Holstein Thai native crossbred (89% Bos taurus × 11% Bos indicus) steers in the fattening phase, with an average age of 2.5 ± 0.1 years and an initial body weight of 603.7 ± 14.3 kg, were used in the energy balance trial. Using a randomized complete block design with five replications, the steers received one of three treatments. The three dietary treatments included substituting cassava pulp with cassava chips and broken rice on a dry matter basis with ratios of 50:0:0, 30:20:0, or 10:20:20. The results show that broken rice is a superior nutrient source and provides greater energy balance (p < 0.01). Despite the cost implications, substituting cassava pulp and chips positively impacts the ensilage pH and reduces the acetic acid concentration (p < 0.01). There was an increase in the lactic acid bacteria count (p < 0.05) and a reduction in the rumen ammonia, propionate, and butyrate concentrations (p < 0.05) without adverse effects (p > 0.05) on digestibility, blood metabolites, or enteric methane emissions. These findings suggest that broken rice is a promising alternative grain-rich ruminant feed. Future research should explore on-farm long-term feeding and economic evaluations to provide a more comprehensive understanding of the practical implications.

Effects of Cattle Breeds and Dietary Energy Density on Intake, Growth, Carcass, and Meat Quality under Thai Feedlot Management System.

This study determines the effects of varying dietary metabolizable energy densities on Holstein Friesian and Charolais crossbred beef cattle in fattening phases. The research focuses on nutrient utilization, ruminal fermentation, growth performance, carcass traits, and meat quality. Thirty-six steers were used in the feeding trial that lasted for six months according to a 2 × 3 factorial arrangement in a randomized complete block design (Factor A, cattle breeds (Holstein Frisian, Charolais crossbred); B, metabolizable energy density (10.5, 11.1 and 11.8 MJ/kg DM)) with six replications. The dietary energy density had no interaction with the cattle breeds (p > 0.05). Despite fewer carcass yields, Holstein Friesian crossbreds indicate superior eating quality to Charolais crossbreds on drip loss, meat iron content, and Warner-Bratzler shear force due to increased intramuscular fat content (p < 0.05) with similar meat color (p > 0.05). Increased dietary energy density positively impacts nutrient and energy intake and rumen fermentation (p < 0.05) but did not affect growth and carcass traits (p > 0.05). This research suggests the potential of Holstein Friesian crossbreds for intensive beef production, providing valuable insights into optimal feeding strategies for achieving quality meat outcomes. On-farm feeding trials are needed to develop a practical and economical Thai beef feedlot management system.