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1.
The aim of this work was to study the genotypic variation for in vitro digestibility and composition traits within maize elite hybrids, and their relationships with in vivo digestibility traits. Experiments using 58 maize hybrids were carried out in four French environments in 1995. Near-infrared reflectance spectroscopy (NIRS) was used to determine in vitro digestibility (whole-plant and cell-wall digestibility) and biochemical composition (starch, soluble carbohydrates, neutral detergent fibre, acid detergent lignin, protein and ash contents). The 58 hybrids were also studied at INRA, Lusignan, France, within a long-term experiment to determine their in vivo digestibility of organic matter and of crude fibre using standard sheep. Genotypic variation was studied and relationships between hybrid mean values for in vitro parameters and in vivo digestibilities were examined. For evaluation and breeding purposes, it is possible to discriminate maize elite hybrids according to their digestibility, especially for discarding low-value genotypes. in vitro parameters, such as in vitro whole-plant digestibility and cell-wall digestibility associated with cell-wall content, can be routinely investigated with NIRS. Accurate criteria that are satisfactorily relevant to reference data of in vivo digestibility evaluated with standard sheep can be obtained to explain about 60% of the variation. 相似文献
2.
The in vivo feeding value of 118 early maize (Zea mays L) hybrids, registered in France between 1958 and 1994, has been estimated
from digestibility measurements with sheep at INRA Lusignan (France). There were great variations in the digestibilities of
organic matter and crude fibre, and in the energy value of these hybrids, ranging respectively between 65.1 and 73.5%, 45.4
and 60.0%, and 0.79 and 0.95 UFL. There was a regular decrease in the average feeding value, regarding the year of registration,
for each of the feeding value traits investigated. From 1958 to date, the frequency of hybrids lower than Mammouth increased,
while the number of hybrids higher than LG11 or Brutus clearly decreased. Across the years, the increase in variations among
hybrids occurred because of the introduction of hybrids with a poorer feeding value, particularly since the end of the 80's.
The extremely efficient genetic pressure in breeding for whole plant yield and stalk standability could explain the drift
in feeding value. A silage maize hybrid with a high yield, a high lodging resistance, and a good feeding value can be available
only if breeders use a digestibility assessment, proved as representative of the digestion in cattle. In addition to a digestibility
evaluation, the prediction of maize ingestibility could be taken into account as soon as a criterion is established.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
【研究目的】本文旨在研究膨化混合料对泌乳后期奶牛泌乳性能、干物质采食量（DMI）和营养物质表观消化率的影响。【方法】试验采用荷斯坦泌乳后期奶牛80头,随机分成2组。对照组精料为常规饲料,试验组精料中的能量、蛋白饲料为膨化饲料。试验期56天。【结果】试验结果表明：膨化混合料可显著增加泌乳牛的日产奶量（P＜0.05）,试验组全期产奶总量及标准乳产量分别为1117.40 kg/头和1128.30 kg/头,比对照组增加56.43 kg/头和50.29 kg/头;膨化混合料对乳脂率和固形物总产量影响显著（P＜0.05）,试验组产脂量、固形物产量分别比对照组高1.85 kg和1.17 kg;膨化混合料可提高奶牛DMI和粗蛋白表观消化率（P＜0.05）,试验组DMI比对照组增加1.57kg/d,有机物的表观消化率在两组间差异不显著。【结论】膨化混合料可提高产奶后期奶牛DMI,对泌乳性能和营养物表观消化率有显著促进作用。 相似文献
4.
The aim of this work was to investigate the genotype × environment interaction for in vivo digestibility of organic matter and of crude fibre in silage maize evaluated with standard sheep experiments. In order to test the genotype × year interaction, the first experiment consisted of taking data subsets out of a 26-year experiment and evaluating in vivo digestibility traits at Lusignan (France) on numerous maize genotypes. In order to test the genotype × location interaction, the second experiment was a specific one whereby five hybrids were cropped in diverse locations and then evaluated from experiments with sheep, at Lusignan. The variation attributed to genotype × environment (either a year or a location) interaction for in vivo digestibility traits was distinctly lower than the variation due to the main genotypic effect. Therefore, the in vivo digestibility of organic matter and of crude fibre in maize genotypes could be accurately assessed from silages cropped in a simple experimental design, which included replicates, but only a small number of years or locations. This also confirmed the results obtained with in vitro digestibility traits from large multi-environmental designs which highlighted the low importance of genotype × environment interactions and contributed to the validation of in vitro criteria. 相似文献
5.
Summary Variation and covariation for agronomic and digestibility traits of silage maize are reported from a compilation of 22 years of experiments with standard sheep. Genotype effects of DOM and DCF were highly significant, even when genotypes were nested in earliness groups or brown-midrib hybrids discarded (Table 2). The genetic variance of crude fiber content was low, but the variance of the DCF was high. The genetic variance of DOM was about 4 times lower than genetic variance of DCF, but broad sense heritability of DOM was higher because of lower residual variance (Table 3). Genetic correlations between grain or crude fiber content and DOM had similar absolute values, 0.65, so each of these two traits was an important but not the unique determinant of silage maize quality. There was no correlation between DCF and grain or crude fiber content. Yield was not related to DOM or DCF within each group of earliness, allowing some quality improvement without agronomic drift (Table 4). Except for late hybrids, most of DOM differences between groups of earliness came from lowering of minimum value, while maximum values were similar. It was the contrary for DCF, with similar minimum values for all groups (Table 5). There was no obvious correlation between year of registration of hybrids and DOM or DCF, but extra new variation seemed obtained only for low values (Figs 1, 2; Table 6). IVDOM according to the APC process was a poor predictor of DOM, especially when brown-midrib hybrids and earliness effects were discarded; but because heritability of this trait was similar to DOM heritability, such enzymatic processes could probably be used to avoid drift towards poor DOM with hybrids bred for higher stalk strength.Abbreviations APC
Amylase Pepsine Cellulase solubility
- DDM
sheep digestibility of dry matter
- DOM
sheep digestibility of organic matter
- DCF
sheep digestibility of crude fiber
- DM
dry matter
- IVDCW
in vitro digestibility of cell wall
- IVDDM
in vitro digestibility of dry matter
- IVDOM
in vitro digestibility of organic matter
- NIRS
near infra-red reflectance spectroscopy
- NDF
neutral detergent fiber
- bm1-brown-midrib-1 allele, bm3-brown
midrib-3 allele 相似文献
6.
轻微至中度热应激对荷斯坦奶牛生理指标及产奶性能的影响 总被引：9，自引：2，他引：7
随机选用16头中国荷斯坦泌乳牛,研究轻微至中度热应激对其生理指标及产奶性能影响。结果表明：（1）泌乳牛在轻微热应激期（THI 74.5±1.0）的生理常数指标与非热应激期（THI 65.2±4.1）差异均不显著（P>0.05）;中度热应激期（THI 84.0±2.4）的各项生理常数指标均显著高于非热应激期（P<0.05）。从非热应激至中度热应激,THI每升高1,直肠温度上升0.04℃;从轻微至中度热应激,THI每升高1,泌乳牛的呼吸频率增加3.4次/min,脉搏增加2.6次/min。（2）在轻微和中度热应激期泌乳牛产奶量分别下降13.8%和26.9%（P<0.01）,产奶量与THI呈极显著负相关（P<0.01）（R= -0.82）,THI每上升1,产奶量下降1.9％。 相似文献
7.
绵羊对4种蛋白饲料日粮营养物质消化动态变化的比较 总被引：2，自引：0，他引：2
试验采用3头35 kg左右的美利奴绵羊研究不同蛋白饲料日粮对绵羊营养物质消化的影响。为自身对照试验设计,整个试验分4期进行,每期3头羊饲喂同一种蛋白饲料日粮。4种蛋白来源分别为棉籽粕、大豆粕、葵粕和菜籽粕。试验结果表明:绵羊采食蛋白来源为棉籽粕的日粮时,干物质、有机物和氮采食量最高,而菜籽粕采食量最低。饲喂棉籽粕日粮,干物质、有机物和纤维素十二指肠流量显著高于大豆粕日粮和菜籽粕日粮(P<0.05)。大豆粕日粮粗蛋白在前胃的消失率最高为33%,其余3组日粮粗蛋白前胃的降解率为16%~20%。到达小肠的菌体蛋白(MCP)量各组间无差异,而到达小肠过瘤胃饲料蛋白的量(率)棉籽粕组显著高于葵粕组、菜籽粕组、大豆粕组。大豆粕组粗蛋白在小肠的表观消化率最低为48%,其余3组日粮粗蛋白小肠表观降解率均为66%。 相似文献
8.
大豆黄酮对奶牛泌乳性能及血浆中激素水平的影响 总被引：1，自引：0，他引：1
zhriver@yahoo.com.cn 《中国农学通报》2006,22(5):20-20
（河南农业大学牧医工程学院,河南郑州 450002） 相似文献
9.
（目的）本研究旨在研究阳离子盐对奶牛生产性能和离子平衡的影响。（方法）试验选用泌乳期、产奶量和胎次都无显著差异的荷斯坦奶牛48头,随机分为4组,各组每头分别饲喂阳离子盐0 g/d（对照组）、20 g/ d（试验Ⅰ组）、30 g/ d（试验Ⅱ组）和40 g/ d（试验Ⅲ组）,试验期共55天。（结果）结果表明：试验组的产奶量普遍提高,但乳脂率、乳蛋白率、乳糖率变化不明显,同时提高了牛乳中K+、Na+、Ca2+、Mg2+,而阴离子Cl-和SO42-离子基本无变化（P>0.05）;血清中K+、Mg2+、Na+、Cl-含量变化不明显（P>0.05）,但显著增加了SO42-离子含量（P<0.05）。（结论）可见,泌乳期奶牛日粮中添加阳离子盐可以提高奶牛的产奶量,维持离子平衡,有利于保证奶牛健康。 相似文献
10.
We determined the effect of N fertilization on dry matter (DM) yield, predicted milk yield, and forage quality of fresh (green chopped) and ensiled forage of two brown midrib (BMR) hybrids, a leafy hybrid, and a conventional silage hybrid. Increasing N rates from 0 to 200 kg ha?1 increased corn grain, stover and whole plant DM yield and milk yield. The forage yield and quality response to N was similar for all hybrids. Nitrogen fertilization increased forage crude protein (CP) concentration but had little effect on other forage quality components. BMR hybrids, F377 and F657, had the lowest grain, stover and whole plant yield but had the highest digestibility and predicted milk yield Mg?1 of forage. Predicted milk yield ha?1 was similar for the BMR, leafy and conventional hybrids. Ensiling reduced starch concentration compared with green chopped forage, but effects on other forage quality variables were less consistent. Hybrid and N fertilization affects were similar for green chopped and ensiled corn forage. 相似文献
11.
为明确不同类型青贮玉米在临沂地区最佳种植密度,设置了4个密度梯度（60 000、75 000、90 000、105 000株/hm 2）,研究种植密度对专用型青贮玉米雅玉8号和粮饲兼用型玉米登海605饲用产量和营养价值的影响。结果表明：密度对不同类型青贮玉米鲜草、干草产量影响显著,密度增加,青贮玉米鲜草产量和干草产量均先增加后减少,在密度75 000株/hm 2时均获得最高鲜草、干草产量。密度对不同类型青贮玉米粗脂肪、粗灰分、酸性洗涤纤维含量和子粒产量、粗蛋白产量、粗脂肪产量、可消化干物质、相对饲喂价值、无氮浸出物含量和总能量影响显著,密度增加,雅玉8号粗蛋白、粗脂肪含量和可消化干物质、干物质采食量、相对饲喂价值和无氮浸出物含量下降,粗灰分、中性洗涤纤维和酸性洗涤纤维含量呈上升趋势,子粒产量、粗蛋白、粗脂肪产量和总能量先增加后减少,在密度75 000株/hm 2均获得最高子粒、粗蛋白、粗脂肪产量。从饲料总能量来说,专用型青贮玉米雅玉8号和粮饲兼用型玉米登海605在山东临沂地区饲用的最佳种植密度均为75 000株/hm 2。 相似文献
12.
为了研究鲁梅克斯K-1对关中奶山羊产奶性能的影响。选取50只健康、体质量、产奶量接近(P>0.5)的关中奶山羊,试验共分5个处理,每个处理10只,各处理每只羊每天均饲喂3 kg粗饲料和1 kg精饲料,对照组粗饲料全喂玉米秸杆青贮,A、B、C、D组用鲁梅克斯青贮分别替代0.5、1、1.5、2 kg玉米秸杆青贮,进行为期50天泌乳试验。结果表明：（1）整个试验期,处理C组共产羊奶1850 kg,处理C组分别比CK、A、B、D组多产奶490、325、260、310 kg,差异极显著(P<0.01);（2）处理C组比CK、A、B、D组奶山羊的乳干物质、乳脂率、乳蛋白及乳糖含量均有所改善,但差异不显著(P>0.5);（3）C组的纯收入为5675元,C组分别比CK、A、B、D组多收入2035、1350、1065、1215元,差异极显著(P<0.01)。鲁梅克斯营养丰富,与玉米秸杆混合青贮能有效提高关中奶山羊产奶量,改善乳蛋白、乳糖及乳脂率,其在粗饲料中添加量在50%为宜。 相似文献
13.
大豆黄酮对奶牛相关产奶性能的影响 总被引：5，自引：0，他引：5
选用4头泌乳约7个月的荷斯坦奶牛,采用前后自身对照方法,对照期饲喂常规日粮,试验期日粮中添加10 mg/kg的大豆黄酮,研究大豆黄酮对泌乳后期奶牛泌乳量、乳成分及乳中激素的影响。结果显示,饲喂大豆黄酮能缓解泌乳后期奶牛产奶量下降的趋势,并在一定程度上提高产奶量;乳蛋白含量显著升高(P<0.01),乳脂率变化不大。激素分析结果表明,乳中T4的含量显著升高(P<0.05),GH,PRL,E2和TSH的含量有升高的趋势,而T3则有下降的趋势。提示大豆黄酮可能通过调节内源性激素水平而间接地影响奶牛泌乳量和乳成分。 相似文献
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15.
美国奶业新特点、新趋势及对中国的启示 总被引：1，自引：0，他引：1
美国奶业发展历史悠久,其生产端、消费端乃至流通贸易方面长期积累的丰富经验,对中国奶业振兴具有一定的参考价值。笔者对2000年以来美国奶业生产、价格、消费、贸易等方面所呈现的新特点进行分析,对奶业相关的支持政策及其变化趋势进行梳理。研究发现,近年来,美国奶牛场数量向北部和西部集中,500头以上规模化牧场成为主流,奶牛存栏增加;技术进步推动奶牛单产突破10 t,生鲜乳产量接近1亿t。基于分级定价的乳成分定价机制不断完善,近5年生鲜乳价格低位运行,2019年快速复苏。乳制品加工业向龙头企业集中,奶酪是主要加工产品。乳制品消费逐年增长,年人均消费量达292.90 kg,奶酪是主要增长点且增速加快。乳制品贸易波动增加,出口目的地集中在北美、东亚和东南亚地区,品类以奶粉、奶酪和乳清为主。奶业产业支持政策广泛涵盖生产、消费、贸易等各环节,各政策间功能互补、协调配套,形成了强大的政策合力与综合效能。美国奶业在产业组织、运行机制、政策配套等方面的经验与做法,对推动完善中国奶业利益联结机制、优化生鲜乳价格形成机制、完善奶业支持政策体系和培育乳制品消费习惯等方面具有重要启示。 相似文献
16.
热应激奶牛血清NO浓度和NOS活力的变化 总被引：1，自引：1，他引：0
为探索不同品种奶牛血清中一氧化氮合成酶（NOS）的活力以及一氧化氮（NO）浓度变化与热应激的关系。此实验在热应激期（THI 82.61±0.60）和非热应激期（THI 47.42±0.51）对荷斯坦牛（n=20）和娟-荷F1牛（n=20）血清NOS活力及NO浓度水平进行测定。结果表明：荷斯坦牛和娟-荷F1牛在热应激期血清NOS的活力均显著低于非热应激期（P〈0.01）;热应激期娟-荷F1牛血清NOS的活力显著低于荷斯坦牛（P〈0.01）,非热应激期二者差异不显著（P〉0.05）;热应激期荷斯坦牛血清NO浓度较非热应激期显著降低（P〈0.05）,娟-荷F1牛有降低趋势,但差异不显著（P〉0.05）;非热应激期荷斯坦牛血清中NO浓度显著高于娟-荷F1牛（P〈0.05）,热应激期二者差异不显著（P〉0.05）。 相似文献
17.
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19.
M. Ghesquière J.-C. Emile J. Jadas-Hécart C. Mousset R. Traineau C. Poisson 《Plant Breeding》1996,115(4):238-244
This paper reports on the first results of feeding value experiments, assessed with sheep, of hybrids between tetraploid Italian ryegrass (Lolium multiflorum, 2n = 4×= 28) and a progenitor of tall fescue, Festuca arundinacea var. glaucescens (2n = 4×= 28). Three hybrid populations resulting from either high, low or no selection for palatability were compared with a variety of Italian ryegrass as control and two varieties of the cultivated hexaploid (2n = 6×= 42) tall fescue, one of which had been selected for high palatability. On average, the hybrid populations were found to be as palatable as the improved tall fescue with voluntary intake (VI), in vivo digestibility of organic matter (DOM), and net energy expressed in fodder units for milk, similar to the best palatable tall fescue and to Italian ryegrass. However, selection for improved palatability among hybrids did not result in any further improvement of other traits, except VI in the hybrid selected for high palatability which significantly exceeded VI of Italian ryegrass. In conclusion, intergeneric hybridization between L. multiflorum and F. arundinacea var. glaucescens led to an immediate increase of feeding value compared with selection for palatability in tall fescue. However, to improve feeding value of hybrids further, similar selection for high palatability appeared questionable and possibly detrimental for other agronomic traits because of complicated inheritance in tetraploid L. multiflorum×F. glaucescens hybrids. 相似文献
20.
Summary The costs associated with yield testing cause maize (Zea mays L.) breeders to search for ways to maximize testing efficiency. The objective of this study was to select individual locations, or a group of locations as preliminary testing sites for yield evaluation of maize hybrids within FAO 600 maturity zone in Yugoslavia. Yield data for 12 locations obtained for the period 1975 to 1984 were used. The predictive potential of the site was judged by the correlations between location means and overall mean (r>0.95), linear regression of locations means on overall mean (b>1.0) and percentage of the 10% overall highest yielding hybrids selected by 10% selection intensity at each location, or at the group of locations (Is>80%). Also factors as average location yield (x) and variation in individual location yield during the period of 10 years (CV) were related to the predictive potential of the site. Differences among locations in all criteria were found. Average yielding locations had higher values of estimators of predictive ability of overall performance than low yielding locations. None of individual locations satisfied all requested criteria. Five locations with highest values for each individual criterion were selected and all possible two, three, four and five-location combinations among them studied. Combinations of two locations could be used for very preliminary screening of hybrids by applying mild selection intensity. A more accurate prediction of overall one-year performance requires an evaluation of hybrids in a minimum of three, but frequently four, selected locations. However, for precise estimation of over-year hybrid performance, testing the hybrids at selected locations in more than one year is necessary. 相似文献