Intake, digestibility and recovery of grains from feces of steers fed different oilseeds

ABSTRACT Oilseed grains are used as a protein and energy source, increasing the energy density of the feed. The goal of the present study was to determine the nutritional profile of canola, crambe and soybean grains recovered from feces, and to evaluate the intake and digestibility of nutrients, rumen fermentation parameters of beef cattle receiving whole grains of oilseeds. Three steers, 350 ± 23.5 kg body weight were distributed in a not contemporary, 3 × 3 double Latin square, and fed oilseed grains. Inclusion of crambe grain reduced dry matter intake by 21.02%, with a higher digestibility coefficient for EE and NDF. The crude protein content of canola and crambe grains recovered were similar, but the EE content was higher for the crambe grain (26.46%). Soybean showed the lowest values of chemical composition for grains recovered from feces. The highest dry matter intake (7.86 kg/day), and the lowest NDF digestibility (0.203g/kg), were found for animals fed soybean. The inclusion of crambe grains reduced the rumen ammonia content (10.97 mg/dL); however, the ruminal pH was not altered by the inclusion of grains in the diet. Canola and soybean grains can be included in the cattle diet without altering dry matter intake; while the inclusion of crambe grains reduces the dry matter intake and the ruminal ammonia content of the animals. Crambe grain showed the highest recovery of dry matter and ether extract from feces.

摘要：油料籽实（oilseed grains）可用作蛋白质与能量来源，能够提升饲料的能量浓度。本研究旨在测定从肉牛粪便中回收的油菜籽（canola）、荠蓝籽（crambe）与大豆籽实的营养组成，并评估饲喂整粒油料籽实的肉牛的养分采食量、消化率及瘤胃发酵参数（rumen fermentation parameters）。选取3头体重为350±23.5 kg的阉牛（steers），采用非同期3×3双拉丁方试验设计，饲喂油料籽实日粮。添加荠蓝籽实可使干物质采食量（dry matter intake）降低21.02%，同时提升醚提取物（ether extract, EE）与中性洗涤纤维（neutral detergent fiber, NDF）的消化系数。从粪便中回收的油菜籽与荠蓝籽实的粗蛋白质含量相近，但荠蓝籽实的醚提取物（EE）含量更高，达26.46%。粪便回收的大豆籽实的各项化学成分含量均为最低。饲喂大豆籽实的试验牛干物质采食量最高（7.86 kg/天），中性洗涤纤维（NDF）消化率最低（0.203 g/kg）。添加荠蓝籽实可降低瘤胃氨态氮含量（10.97 mg/dL），但日粮中添加籽实并未对瘤胃pH值产生显著影响。油菜籽与大豆籽实可添加至肉牛日粮中，且不会改变干物质采食量；而添加荠蓝籽实则会降低试验牛的干物质采食量与瘤胃氨态氮含量。荠蓝籽实的粪便干物质与醚提取物回收率最高。