Rode L M, Yang W Z, Beauchemin K A
Livestock Sciences Section, Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Canada.
J Dairy Sci. 1999 Oct;82(10):2121-6. doi: 10.3168/jds.S0022-0302(99)75455-X.
Twenty multiparous lactating Holstein cows in early lactation were used to investigate effects of exogenous fibrolytic enzyme supplementation on dry matter intake, milk production, and digestibility. Cows were blocked according to parity, expected calving date, and milk yield in the previous lactation, and then randomly assigned after calving to two treatments: control or enzyme. The enzyme mixture, which contained mainly xylanase and cellulase activities (Pro-Mote, Biovance Technol. Inc., Omaha, NE), was added to the concentrate to supply 1.3 g/kg of total mixed ration (dry matter basis). The total mixed rations contained 24% corn silage, 15% alfalfa hay, and 61% barley concentrate (dry matter basis) and were offered for ad libitum intake. Enzyme addition did not affect dry matter intake. However, total digestibility of nutrients, determined using Cr2O3, was dramatically increased by enzyme treatment (dry matter, 61.7 vs. 69.1%; neutral detergent fiber, 42.5 vs. 51.0%; acid detergent fiber, 31.7 vs. 41.9%; crude protein, 61.7 vs. 69.8%). Consequently, milk yield tended to increase (35.9 vs. 39.5 kg/d). Percentage of milk fat was lower, and percentages of milk protein tended to be lower for cows fed a diet supplemented with enzymes, such that component yields were similar for cows fed either diet. Energy deficiency was numerically lower for cows fed a diet supplemented with enzymes than for cows fed the control diet (-3.62 vs. -3.33 Mcal/d). Supplementing dairy cow diets with a fibrolytic enzyme mixture has the potential to enhance milk yield and nutrient digestibility of cows in early lactation without changing feed intake.
选用20头处于泌乳早期经产的荷斯坦奶牛，研究补充外源纤维分解酶对干物质摄入量、产奶量和消化率的影响。奶牛按胎次、预期产犊日期和上一胎次的产奶量进行分组，产犊后随机分为两组处理：对照组和酶处理组。将主要含有木聚糖酶和纤维素酶活性的酶混合物（Pro-Mote，Biovance Technol. Inc.，奥马哈，内布拉斯加州）添加到精料中，使每千克全混合日粮（干物质基础）的添加量为1.3 g。全混合日粮含有24%的玉米青贮、15%的苜蓿干草和61%的大麦精料（干物质基础），自由采食。添加酶对干物质摄入量没有影响。然而，酶处理显著提高了使用Cr2O3测定的养分总消化率（干物质，61.7%对69.1%；中性洗涤纤维，42.5%对51.0%；酸性洗涤纤维，31.7%对41.9%；粗蛋白，61.7%对69.8%）。因此，产奶量有增加的趋势（35.9对39.5 kg/d）。补充酶的奶牛所产牛奶的乳脂率较低，乳蛋白率也有降低的趋势，因此两种日粮喂养的奶牛的成分产量相似。补充酶的奶牛能量缺乏在数值上低于对照组奶牛（-3.62对-3.33 Mcal/d）。在奶牛日粮中补充纤维分解酶混合物有可能提高泌乳早期奶牛的产奶量和养分消化率，而不改变采食量。
