Dietary Protein Effects on Nitrogen Excretion and Manure Characteristics of Lactating Cows
Dietary Protein Effects on Nitrogen Excretion and Manure Characteristics of Lactating Cows
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日粮蛋白质对泌乳牛氮排泄和粪便特性的影响
DOI：
10.13031/2013.27637
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发表时间：
1996
影响因子：
1.5
通讯作者：
C. J. Wilcox
中科院分区：
文献类型：
--
作者：
A. Tomlinson;W. Powers;H. H. V. Horn;R. Nordstedt;C. J. Wilcox
在初步实验中，向 34 头泌乳奶牛饲喂 12 种日粮，目的是确定日粮蛋白质水平和来源对氮排泄的影响，这是对奶牛场粪便氮流量和利用率进行预算所需的第一个估计。分别完整收集尿液和粪便，用于测定氮的消化率以及尿液和粪便排泄量。使用DM摄入量和氮摄入量作为主要预测因子，建立了预测尿液和粪便中氮排泄量的方程。模型中包括产奶量或体重并没有考虑到明显的额外变化。根据这些方程估计的粪便加尿液氮排泄量与 NRC 方程和假设所消耗的氮要么分泌在牛奶中，要么排泄在尿液和粪便中（饮食氮减去牛奶氮）的估计值非常一致。 635 公斤荷斯坦奶牛每天消耗 17.8 公斤干物质（15.3% CP）（即每天 22.7 公斤牛奶所需的估计量），预计氮排泄量为 325 克（150 克尿液氮和 175 克粪便氮）。粪便中 DM 排泄量平均占 DM 摄入量的 34.3%（典型奶牛为 6.1 kg），其中 88.2% 为挥发性固体；每日尿液干物质平均为 0.9 千克/天（20 千克尿液/天平均为 0.045% 干物质），挥发性固体含量为 47.8%。此外，还测定了粪便（ADF、NDF、粗脂肪、Ca、P、Mg、K、Na、Fe、Zn、Cu、Mn 和 Mo）和尿液（Ca、K、Mg、Na、P）的成分和每日总排泄物。与氮一样，每天排出的各种组分的量与干物质的摄入量密切相关（随产奶量的变化而变化），并且比组成百分比的变化要小得多。缩写键：BM = 血粉，Ca-LCFA = 长链脂肪酸钙皂，CP = 粗蛋白 = N ¥ 6.25，DM = 干物质，DMI = DM 摄入量，FtM = 羽毛粉，RUP = 瘤胃未降解蛋白质，SBM = 豆粕。
In the primary experiment, 12 diets were fed to 34 lactating cows with the objective to determine effects of level and source of dietary protein on N excretion, the first estimate needed to budget manure N flow and utilization on dairy farms. Complete collection of urine and feces separately allowed for determination of digestibilities and urine and fecal excretion of N. Equations to predict N excretion in urine and feces were developed using DM intake and N intake as the primary predictors. Including milk yield or body weight in the model did not account for appreciable additional variation. Fecal plus urine N excretions estimated from these equations agreed closely with NRC equations and estimates made assuming that N consumed was either secreted in milk or excreted in urine and feces (diet N minus milk N). Predicted N excretion for 635 kg Holstein cows consuming 17.8 kg/d dry matter (15.3% CP), which is the estimated amount required for 22.7 kg milk/d, was 325 g (150 g urine N and 175 g feces N). Fecal DM excretion averaged 34.3% of DM intake (6.1 kg for typical cow) and was 88.2% volatile solids; daily urine dry matter averaged 0.9 kg/d (20 kg urine/d averaging 0.045% dry matter) and was 47.8% volatile solids. Additionally, compositions and total daily excretions were determined for feces (ADF, NDF, crude fat, Ca, P, Mg, K, Na, Fe, Zn, Cu, Mn, and Mo) and urine (Ca, K, Mg, Na, P). As with N, amounts of various fractions excreted daily were closely associated with DM intake (which varies with milk production) and were much less variable than percentage compositions. Abbreviation key: BM = blood meal, Ca-LCFA = Ca soaps of long-chain fatty acids, CP = crude protein = N ¥ 6.25, DM = dry matter, DMI = DM intake, FtM = feather meal, RUP = ruminally undegraded protein, SBM = soybean meal.