Rumen parameters and intake in goats fed cassava chips and alfalfa

ABSTRACT Pasture-based production systems and alternative foods can be used to reduce goat milk production costs by around 20%.The objective of this study was to examine the effect of substituting the corn and soybean meal of the concentrate with cassava chips and alfalfa, respectively, on the feed intake, fermentation, and rumen degradability parameters of adult, dry, empty, rumen-cannulated Saanen goats reared in a feedlot. The experiment was conducted as a Latin square design in which the following diets were tested: ground corn and soybean meal; cassava chips and soybean meal; ground corn and alfalfa; and cassava chips and alfalfa. The following variables were evaluated: feed intake, rumen parameters, short-chain fatty acid (SCFA) production, and feed degradation kinetics. Inclusion of cassava chips and alfalfa did not influence feed intake or ammonia production. Rumen pH and SCFA production were influenced by the collection times, presenting a high pH (6.29) at the first measurement (07 h 00) and then decreasing, thus influencing SCFA production throughout the day.Acetic acid and total SCFA production were influenced by the diets, with the highest values for the cassava/alfalfa diet (68.03 and 93.64 mM 100 mM-1, respectively) and the lowest values for the corn/soybean diet (55.40 and 76.03 mM 100 mM-1, respectively).Nutrient digestibility was also influenced by diets, with those containing cassava and cassava/alfalfa, providing the greatest effective degradability (57.57 to 0.02 h-1 and 53.49 to 0.05 h-1; 57.25 to 0.02 h-1and 53.26 to 0.05 h-1, respectively). This finding demonstrates that cassava and alfalfa can substitute the corn and soybean meal of concentrates without changing feed intake or the ruminal environment of goats. Rather, this substitution improves acetic acid production and diet digestibility.

摘要
以牧场为基础的生产体系与替代饲料可将山羊奶的生产成本降低约20%。本研究旨在探究分别以木薯片和苜蓿替代精饲料中的玉米与豆粕，对圈养条件下成年、干奶、空怀且安装瘤胃瘘管的萨能奶山羊的采食量、发酵参数及瘤胃降解特性的影响。本实验采用拉丁方设计，共设置4种试验日粮：粉碎玉米+豆粕组、木薯片+豆粕组、粉碎玉米+苜蓿组以及木薯片+苜蓿组。本研究评估的指标包括采食量、瘤胃相关参数、短链脂肪酸（short-chain fatty acid, SCFA）生成量以及饲料降解动力学。添加木薯片与苜蓿对山羊的采食量及氨生成量无显著影响。瘤胃pH值与SCFA生成量受采样时间影响：首次采样（7:00）时pH值较高（6.29），随后逐渐降低，进而全天的SCFA生成量随之变化。乙酸及总SCFA生成量受日粮类型影响：木薯片/苜蓿组的生成量最高（分别为68.03 mM和93.64 mM/100 mM），玉米/豆粕组最低（分别为55.40 mM和76.03 mM/100 mM）。营养物质消化率同样受日粮类型影响：含木薯片的日粮与木薯片/苜蓿日粮的有效降解率最高，分别为57.57（对应降解速率0.02 h⁻¹）与53.49（对应降解速率0.05 h⁻¹）、57.25（对应降解速率0.02 h⁻¹）与53.26（对应降解速率0.05 h⁻¹）。本研究结果表明，木薯片与苜蓿可分别替代精饲料中的玉米与豆粕，且不会改变山羊的采食量及瘤胃内环境；相反，该替代方案可提升乙酸生成量与日粮消化率。