片状密度对泌乳奶牛日粮中蒸汽加工玉米饲喂价值的影响。

Influence of flake density on the feeding value of steam-processed corn in diets for lactating cows.

作者信息

Plascencia A, Zinn R A

机构信息

Instituto de Ciencias Veterinarias, Mexicali, Mexico.

出版信息

J Anim Sci. 1996 Feb;74(2):310-6. doi: 10.2527/1996.742310x.

DOI:10.2527/1996.742310x

PMID:8690666

Abstract

Four primiparous Holstein cows (112 d in lactation) with cannulas in the rumen and proximal duodenum were used in a 4 x 4 Latin square design. Dry-rolled (DR) corn (density .52 kg/L) was compared with stream-flaked (SF) corn processed to three flake densities: .39, .32, and .26 kg/L. The basal diet contained (DM basis) 43.4% alfalfa hay, 39.5% corn (DR or SF), 2.2% yellow grease, 9.6% cane molasses, .7% sodium bicarbonate, and 4.6% protein-mineral supplement. Steam flaking increased DM intake (P < .01). There were no treatment effects on ruminal pH (P > .10). Ruminal molar ratios of acetate and propionate were lower (P < .01) for SF than for DR corn and declined (linear component, P < .01) as flake density decreased. Ruminal digestibility of OM was not affected (P > .10) by corn processing. Ruminal starch digestibility increased (linear component, P < .05) as flake density decreased. Ruminal ADF digestibility was decreased by SF (P < .01); this effect was exacerbated by degree of processing (linear component, P < .05). Ruminal N efficiency (duodenal nonammonia N/N intake) was greater (P < .10) for SF than for DR corn because of an improved (P < .10) microbial efficiency. Steam flaking at all densities increased postruminal digestibility of OM (42.4%, P < .01), starch (84.9%, P < .01) N (13.6%, P < .01), and lipid (11.8%, P < .05). Total-tract digestibilities of OM, N, starch, DE and ME were greater (15.2, 11.5, 25.2, 14.9, and 20.0%, respectively, P < .01) for SF (mean of the three densities) than for DR corn. Total-tract digestibility of starch increased (linear component, P < .10) with degree of processing. However, this effect was offset by decreased (linear and quadratic components, P < .05) ADF digestibility. Steam flaking improved the feeding value of corn for lactating cows by improving diet acceptability and digestibility of lipid, starch, and N. Steam flaking increased the estimated NEl of corn by 33%. Optimal flake density probably is between .32 and .39 kg/L.

摘要

选用4头初产荷斯坦奶牛（泌乳112天），瘤胃和十二指肠近端装有套管，采用4×4拉丁方设计。将干碾压（DR）玉米（密度0.52千克/升）与蒸汽压片（SF）玉米进行比较，蒸汽压片玉米加工成三种片密度：0.39、0.32和0.26千克/升。基础日粮（以干物质计）包含43.4%苜蓿干草、39.5%玉米（DR或SF）、2.2%黄色油脂、9.6%甘蔗糖蜜、0.7%碳酸氢钠和4.6%蛋白质矿物质补充料。蒸汽压片提高了干物质采食量（P<0.01）。对瘤胃pH值无处理效应（P>0.10）。SF组瘤胃乙酸和丙酸的摩尔比低于DR玉米组（P<0.01），且随着片密度降低而下降（线性成分，P<0.01）。玉米加工对瘤胃有机物消化率无影响（P>0.10）。瘤胃淀粉消化率随着片密度降低而增加（线性成分，P<0.05）。SF组瘤胃酸性洗涤纤维消化率降低（P<0.01）；加工程度加剧了这种效应（线性成分，P<0.05）。由于微生物效率提高（P<0.10），SF组瘤胃氮效率（十二指肠非氨氮/氮摄入量）高于DR玉米组（P<0.10）。所有密度的蒸汽压片均提高了瘤胃后段有机物（42.4%，P<0.01）、淀粉（84.9%，P<0.01）、氮（13.6%，P<0.01）和脂质（11.8%，P<0.05）的消化率。SF组（三种密度的平均值）的全肠道有机物、氮、淀粉、消化能和代谢能消化率均高于DR玉米组（分别为15.2%、11.5%、25.2%、14.9%和20.0%，P<0.01）。全肠道淀粉消化率随着加工程度增加而增加（线性成分，P<0.10）。然而，这种效应被酸性洗涤纤维消化率降低（线性和二次成分，P<0.05）所抵消。蒸汽压片通过提高日粮可接受性以及脂质、淀粉和氮的消化率，改善了玉米对泌乳奶牛的饲喂价值。蒸汽压片使玉米的估计净能增加了33%。最佳片密度可能在0.32至0.39千克/升之间。