Comparing the protein source and frequency of supplementation of forage intake, competitive feeding interactions, and nutrient utilization for beef cattle fed low-quality forage

使用已保留供以后使用的饲料（储存的饲料）和使用谷物收获后残留的作物残留物，使牛肉生产者为他们的牛提供了一个反季节放牧的选择。然而，储存的饲料，特别是本地牧场，和作物残茬的粗蛋白质含量往往很低。饲粮中缺乏粗蛋白质会限制采食量、饲料在瘤胃（肉牛消化道的第一部分）的消化率、饲料从瘤胃流出的速度和饲料的总体消化率。重要的是，这种粗蛋白质缺乏症可以用高粗蛋白质含量的饲料加以纠正。美国的研究表明，作为乙醇生产的副产品，酒糟是一种适当的补充物，可以纠正储存的饲料和作物残留物可能造成的粗蛋白质缺乏。他们还证明，不频繁的补充（每两天）可以弥补低质量的饲料和每天补充。虽然以前没有研究过，但不频繁地补充蛋白质可能会减少在补充饲料时对饲料的竞争，因为隔天饲喂更多的蛋白质。****虽然酒糟是一种合适的蛋白质补充，但最近酒糟加工的变化（去除部分脂质）需要进一步评估这种饲料。此外，酒糟中真菌毒素的风险可能会限制酒糟作为饲料来源的使用。在加拿大，菜籽粕是一种当地生产的蛋白质补充剂，以其高质量的蛋白质来源而闻名，可以喂给牛肉和奶牛。目前关于使用油菜籽粕作为牛食用低质量饲料的补充的信息有限。本研究将评估与菜籽粕相比，低脂酒糟作为蛋白质补充剂对食用低品质饲料的肉牛的影响。该研究预计将提供有关补充饲养管理如何影响肉牛饲养行为的必要信息，并比较降低脂质含量的菜籽粕和酒糟作为肉牛蛋白质补充剂的有效性。**********

Use of forage that has been reserved for later use (stockpiled forage) and the use of crop residues that remain after cereal grains have been harvested allow beef producers to provide an out of season grazing option for their cattle. However, stockpiled forage, particularly native range, and crop residues are often low in crude protein. Feeding diets deficient in crude protein limits feed intake, digestibility of the feed in the rumen (the first part of the digestive tract for beef cattle), passage of feed out of the rumen, and overall digestibility of those feeds. Importantly, this crude protein deficiency can be corrected using feeds with a high crude protein content. Research in the United States has demonstrated that distillers grains, a byproduct arising from ethanol production, are a suitable supplement to correct for the crude protein deficiency that may occur with stockpiled forage and crop residues. They have also demonstrated that infrequent supplementation (every second day) can compensate for low quality forage equally as well as daily supplementation. While not investigated previously, providing the protein supplement infrequently may reduce competition for the feed at the time of supplementation as a greater quantity is fed on alternate days. ****While distillers grains are a suitable protein supplement, recent changes in processing of distillers grains (removing part of the the lipid) warrant further evaluation of this feedstuff. Additionally, the risk for mycotoxins in distillers grains may constrain the use of distillers grains as a feed source. In Canada, canola meal is a locally produced protein supplement known for its high quality as a protein source when fed to beef and dairy cattle. There is currently a limited amount of information regarding the use of canola meal as a supplement for cattle consuming low-quality forages. This study will evaluate the effects of using distillers grains with a low-lipid content in comparison to canola meal as protein supplements for beef cattle consuming low-quality forages. The study is expected to provide needed information on how supplemental feeding management affects feeding behaviour of beef cattle and to compare the effectiveness of canola meal and distillers grains with a reduced lipid content as protein supplements for beef cattle.**********