Donkin S S, Koser S L, White H M, Doane P H, Cecava M J
Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
J Dairy Sci. 2009 Oct;92(10):5111-9. doi: 10.3168/jds.2009-2201.
Growth of the corn ethanol industry has created a need for alternatives to corn for lactating dairy cows. Concurrent expansion in soydiesel production is expected to increase availability and promote favorable pricing for glycerol, a primary co-product material. The objective of this study was to determine the feeding value of glycerol as a replacement for corn in diets fed to lactating dairy cattle. Sixty lactating Holstein cows housed in individual tie stalls were fed a base diet consisting of corn silage, legume forages, corn grain, soyhulls, roasted soybeans, and protein supplements. After a 2-wk acclimation period, cows were fed diets containing 0, 5, 10, or 15% refined glycerol for 56 d. Cows were milked twice daily and weekly milk samples were collected. Milk production was 36.3, 37.2, 37.9, and 36.2 +/- 1.6 kg/d and feed intake was 23.8, 24.6, 24.8, and 24.0 +/- 0.7 kg/d for 0, 5, 10, and 15% glycerol treatments, respectively, and did not differ except for a modest reduction in feed intake during the first 7 d of the trial for 15% glycerol (treatment x time effect). Milk composition was not altered by glycerol feeding except that milk urea nitrogen was decreased from 12.5 +/- 0.4 to 10.2 +/- 0.4 mg/dL with glycerol addition. Cows fed diets containing 10 and 15% glycerol gained more weight than those fed rations containing 0 or 5% glycerol but body condition scores did not differ with glycerol feeding. The data indicate that glycerol is a suitable replacement for corn grain in diets for lactating dairy cattle and that it may be included in rations to a level of at least 15% of dry matter without adverse effects on milk production or milk composition.
玉米乙醇产业的发展使得泌乳奶牛需要以其他饲料替代玉米。预计同时扩大的大豆柴油生产将增加甘油（一种主要的副产品原料）的供应，并促使其价格更有利。本研究的目的是确定甘油替代泌乳奶牛日粮中玉米的饲喂价值。将60头泌乳荷斯坦奶牛单独饲养在栓系牛舍中，饲喂由玉米青贮、豆科牧草、玉米籽粒、大豆皮、烤大豆和蛋白质补充剂组成的基础日粮。经过2周的适应期后，奶牛饲喂含0%、5%、10%或15%精制甘油的日粮，持续56天。奶牛每天挤奶两次，每周采集牛奶样本。0%、5%、10%和15%甘油处理组的牛奶产量分别为36.3、37.2、37.9和36.2±1.6千克/天，采食量分别为23.8、24.6、24.8和24.0±0.7千克/天，除15%甘油处理组在试验的前7天采食量略有下降外（处理×时间效应），其他处理组之间没有差异。甘油饲喂并未改变牛奶成分，只是添加甘油后牛奶尿素氮从12.5±0.4降至10.2±0.4毫克/分升。饲喂含10%和15%甘油日粮的奶牛比饲喂含0%或5%甘油日粮的奶牛体重增加更多，但体况评分不受甘油饲喂的影响。数据表明，甘油是泌乳奶牛日粮中玉米籽粒的合适替代品，并且可以在日粮中添加至干物质的至少15%，而不会对牛奶产量或牛奶成分产生不利影响。
