Quantifying the aging response and nutrient composition for muscles of the beef round

The objective of this study was to determine the optimal postmortem aging period and nutrient composition for Beef Value Cuts of the round. Forty USDA Select and 40 Premium USDA Choice beef carcasses were selected from a commercial beef packing plant in Colorado over a 12-wk period. The bottom and inside rounds were collected from both sides of each carcass for further fabrication into the following muscles: adductor, gastrocnemius, gracilis, pectineus, and superficial digital flexor. Each pair of muscles was cut into 7 steaks and randomly assigned to 1 of the following aging periods: 2, 4, 6, 10, 14, 21, and 28 d, and placed in refrigerated storage (2°C, never frozen). Upon completion of the designated aging period, steaks were removed from storage, cooked to a peak internal temperature of 72°C, and evaluated using Warner-Bratzler shear force (WBSF). A 2-way interaction was detected (P < 0.05) between individual muscle and postmortem aging period. The WBSF of all muscles except the superficial digital flexor decreased with increased time of postmortem aging. Quality grade did not affect (P > 0.05) WBSF values for the adductor, gastrocnemius, pectineus, and superficial digital flexor muscles. Exponential decay models were used to predict the change in WBSF from 2 to 28 d postmortem (aging response). The adductor, gastrocnemius, Select gracilis, Premium Choice gracilis, and pectineus required 21, 14, 23, 23, and 25 d, respectively, to complete the majority of the aging response. To determine the nutrient composition of the adductor, gastrocnemius, gracilis, pectineus, semimembranosus, and superficial digital flexor, bottom and inside rounds were collected from 10 USDA Select and 10 Premium USDA Choice carcasses and fabricated into the respective muscles, cut into 2.54-cm cubes, frozen (-20°C), and then homogenized. The adductor, gracilis, pectineus, semimembranosus, and superficial digital flexor were analyzed for DM, moisture, CP, and ash percentages. All muscles were evaluated for total lipid, fatty acid, and cholesterol composition. When quality grades were combined, all muscles fell into the extra lean or lean categories specified by USDA guidelines. Results of this study illustrate the potential for Beef Value Cuts of the round to be sold in food service operations and retail stores with marketing emphasis being placed on the exceptional leanness and acceptable tenderness of these cuts.     

壳聚糖对肉牛生长性能及营养物质消化率的影响

试验旨在研究壳聚糖(chitosan,CHI)对肉牛生长性能及营养物质表观消化率的影响。选择体重、月龄接近,健康无病的24头西门塔尔育肥公牛,随机分为3个日粮处理组,每组8头牛,饲养试验分前、中、后三期,每期28 d,共84 d。三组日粮分别是在基础日粮中添加0、500和1 000 mg/kg的壳聚糖配制而成。结果表明:试验全期500 mg/kg壳聚糖组的平均日增重(ADG)和日采食量(ADFI)最高、料肉比(F/G)最低;日粮添加500 mg/kg壳聚糖可提高肉牛干物质、蛋白质、能量和钙表观消化率。说明日粮中添加500 mg/kg壳聚糖可提高肉牛营养物质的消化率,进而促进肉牛的生长。     

不同年龄紫穗槐对沙化土壤的改良效应

以毛乌素沙地南缘沙化地不同种植年限的紫穗槐（Amorpha fruticosa）为研究对象,探讨了不同种植年限紫穗槐对沙地的恢复效应。分析了紫穗槐灌丛土壤的机械组成、养分含量以及不同种植年限紫穗槐土壤养分与沙尘粒之间的相关性。结果显示,紫穗槐灌丛的土壤细化程度随着种植年限的增加逐渐增大,表层（0～10 cm）土壤的细化程度为1951年>1976年>1983年>2005年, 1951年种植的紫穗槐的沙尘粒含量达到了4.3%;各种植年份紫穗槐土壤垂直剖面pH值自下而上逐渐降低,表层土壤（0～10 cm）pH值最低,同土层不同年份紫穗槐灌丛土壤pH值基本随种植年限延长而降低;0～20 cm土层中养分含量（除全钾和铵态氮）均出现了不同程度的增加,有机碳、全氮、硝态氮、全磷和速效磷等含量均随着种植年限的增加而增加,铵态氮和全钾含量则无明显规律。     

饲料中添加紫花苜蓿鲜草对肉牛生长性能及养分表观消化率的影响

为研究紫花苜蓿鲜草对肉牛生长性能及养分表观消化率的影响,采用单因素设计试验,选择体重相近的肉牛90头,随机分成3组,每组3个重复,每个重复10头。1组为空白对照组饲喂基础日粮,2、3组分别在风干物质的基础上添加5%、10%的紫花苜蓿鲜草,预试验10 d,试验期为60 d,在试验期间测定肉牛生长性能和养分表观消化率。结果表明:(1)试验3组的试验末重、平均日增重分别较对照组提高3.30%、14.77%(P <0.05),试验2组和3组的平均日采食量均高于1组(P> 0.05),试验3组的料重比分别较对照组降低7.20%(P <0.05);(2)试验2、3组的粗脂肪、粗灰分、钙、磷的表观消化率均高于1组(P> 0.05);试验3组粗蛋白质、中性洗涤纤维、酸性洗涤纤维表观消化率分别较对照组提高13.85%、18.83%、21.03%(P <0.05)。结论,10%紫花苜蓿鲜草可以提高肉牛的生长性能和养分表观消化率。     

不同管理模式与日粮营养水平对热区肉牛育肥效果的影响

为了研究不同品种、不同管理模式与营养水平对热区肉牛育肥的影响,试验一采用安格斯牛、西门塔尔牛杂交后代和婆罗门牛、本地黄牛与1/2婆罗门牛×1/4莫累灰牛×1/4云南黄牛(BMY牛)5个品种各10头,通过90 d生长性能与平均日增重(ADG)测定,筛选出BMY牛为适宜热区推广品种;试验二选取体重约160 kg的BMY公牛40头,分成5组,每组8头,分别采用全放牧不补饲、自由放牧+补饲精料1.0 kg、舍饲牧草+补饲精料1.0 kg、2.0 kg、3.0 kg的方式,在热区进行相同品种不同管理模式与日粮营养水平育肥对比试验。结果表明:相同管理模式与日粮营养水平下,BMY牛对热区环境的适应性与生长性能表现最好;在相同品种同等营养水平下,舍饲育肥的效果明显优于放牧管理;在相同品种相同管理条件下,保持3.0 kg日粮营养水平可获最高育肥效益。说明在我国热区选择BMY牛并保持3.0 kg以上日粮营养水平舍饲育肥能获取最优经济效益。     

Effects of quarter individual and conventional milking systems on teat condition

An on-farm experiment was performed to investigate the effects of two milking systems on teat condition. An auto-tandem milking parlor made by GEA^® with a conventional milking cluster (CON) and a single tube milking system called MultiLactor^® (MULTI) from Siliconform GmbH were tested. For both milking system, in total 73 animals were milked over a period of seven months. To assess the effect of milking on teat condition, each teat was scored according to teat-condition evaluation systems. To evaluate teat condition, the teat color, ring formation at the teat base and formation of teat hyperkeratosis were assessed. The evaluation was conducted once a month after milking. The collected data were then statistically analyzed with generalized linear mixed models. The only differences found between the two milking systems occurred with respect to their effect on teat color. MULTI showed significantly better scores compared to CON. There were no significant differences between the milking systems with regard to teat-end hyperkeratosis and ring formation at the teat base.     

半胱胺对肉牛生产性能及养分消化率影响的研究

选用西门塔尔杂交公牛64头,采用随机分组的设计方式,随机分为4组,每组16头,每组添加不同剂量半胱胺,分别为5、10、20、0g/头·d。结果表明:试验期间各组生长无不良状况,淘汰率为0;采食量正常,且各组间采食量无明显差异。试验期试验1、2、3、对照组平均日增重分别为1065g、1025g、1217g、1052g,其中试验3组显著高于其它3组(P<0.05),试验1组比对照组略高,试验2组比对照组略低,但均差异不显著(P>0.05)。各组粗料料肉比分别为12.37、13.42、11.21、12.63,精料料肉比分别为3.09、3.24、2.28、3.13,第3组明显低于其它各组(P<0.01),第1组显著低于2、对照组(P<0.05),2、对照组差异不显著。粗蛋白消化率试验3组高于对照组且差异显著(P<0.05),粗脂肪消化率极显著高于对照组(P<0.01);中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)消化率各组差异不显著(P>0.05)。对照组获利润2.55元,第3组获利润3.47元,比对照组净增36%,是对照组的1.36倍,经济效益明显增加。     

复合植物精油对肉牛生长性能、养分消化及氮代谢的影响

文章旨在评估复合植物精油对肉牛生长性能、营养物质表观消化及氮代谢的影响.试验将平均体重为(203.16±0.29)kg的108头肉牛随机分为3组,每组36头,每6头牛为1个重复.对照组饲喂全混合日粮,同时自由采食小麦秸秆,T1组和T2组分别饲喂全混合日粮+30和60 mg/kg植物精油,自由采食小麦秸秆.经过28周的饲...     

Effects of different finishing systems on carcass traits, fatty acid composition, and beef quality characteristics of young Eastern Anatolian Red bulls

The effects of three finishing systems on carcass composition and other characteristics of meat were studied in 15 young Eastern Anatolian Red bulls in Eastern Turkey. For 93?days, five bulls grazed pasture (P), five grazed the same pasture and were given concentrate supplementation (P + C), and five grazed the same pasture for 93?days, and then for an additional 40?days, they received concentrate in a barn (PF). Carcasses of the P bulls were lighter and leaner than those of the PF animals. Compared with the P carcasses, PF carcasses had a greater percentage of kidney, pelvic, and heart fat (P?相似文献   

异丁酸对西门塔尔牛增重、日粮养分消化和甲烷排放的影响简

 试验选用３６头１２月龄左右、体况良好、体重相近的西门塔尔牛,随机分为４组,测定异丁酸（０,０．０２,０．０４和０．０６ｇ／ｋｇ· ｄ）对日粮养分消化率、增重性能和甲烷排放的影响。结果表明,日粮添加异丁酸后,０．０４和０．０６ｇ／（ｋｇ· ｄ）组有机物（ｏｒｇａｎｉｃｍａｔｔｅｒ,ＯＭ）消化率显著高于对照组,处理组粗蛋白（ｃｒｕｄｅｐｒｏｔｅｉｎ,ＣＰ）消化率显著高于对照组,无氮浸出物（ｎｉｔｒｏｇｅｎｆｒｅｅｅｘｔｒａｃｔ,ＮＦＥ）消化率差异不显著,０．０４ｇ／（ｋｇ· ｄ）组中性洗涤纤维（ｎｅｕｔｒａｌｄｅｔｅｒｇｅｎｔｆｉｂｒｅ,ＮＤＦ）消化率显著高于对照组和０．０２ｇ／（ｋｇ· ｄ）组（P＜０．０５）,０．０４ｇ／（ｋｇ· ｄ）组酸性洗涤纤维（ａｃｉｄｄｅｔｅｒｇｅｎｔｆｉｂｒｅ,ＡＤＦ）消化率显著高于对照组和其他处理组（P＜０．０５）;试验期间０．０４ｇ／（ｋｇ· ｄ）组和０．０６ｇ／（ｋｇ· ｄ）组日增重显著高于对照组（P＜０．０５）,但与０．０２ｇ／（ｋｇ· ｄ）组差异不显著;肉牛干物质采食量在试验期间０．０４ｇ／（ｋｇ· ｄ）组显著低于对照组（P＜０．０５）,其他组间差异不显著,０．０４ｇ／（ｋｇ· ｄ）组和０．０６ｇ／（ｋｇ· ｄ）组每千克增重消耗饲料显著低于对照组和０．０２ｇ／（ｋｇ· ｄ）组（P＜０．０５）;此外,玉米秸秆日粮中添加异丁酸后,甲烷能呈降低趋势,０．０４ｇ／（ｋｇ· ｄ）和０．０６ｇ／（ｋｇ· ｄ）组显著低于对照组（P＜０．０５）。由此推断日粮添加异丁酸后对增重性能＼营养物质消化和降低甲烷排放有显著促进作用,适宜添加水平为０．０４ｇ／（ｋｇ· ｄ）。     

收割时期和收割高度对小麦秸秆营养成分和消化率的影响

文章旨在明确收割时期和收割高度对小麦秸秆营养成分和体外消化率的影响。试验选取山农22号小麦品种作为研究对象,分别在3个成熟期进行不同收割高度的取样。收割时期分别为蜡熟期的倒数2周、1周和0周;收割高度分别为距离地面5cm、10cm和15cm。结果表明,收割时期和收割高度均影响小麦秸秆营养成分和体外消化率。小麦秸秆中可溶性糖、淀粉和粗蛋白质含量随收割时期的推迟显著下降(P<0.05)。随着收割时期的推迟,小麦秸秆中中性洗涤纤维含量和酸性洗涤纤维含量逐渐升高(P<0.05),钙和磷含量逐渐降低(P<0.05)。小麦秸秆中粗蛋白质、钙和磷含量随着收割高度的增加显著升高(P<0.05),可溶性糖、中性洗涤纤维和酸性洗涤纤维含量显著下降(P<0.05)。因此,为了获得质量较高的小麦青贮,需要在小麦蜡熟期倒数第2周,在距离地面15cm的高度收获小麦秸秆。     

播期对燕麦和豌豆营养成分及瘤胃降解率的影响

试验通过研究不同播期对燕麦和豌豆混播作物饲用价值的影响,看是否值得在东农冬小麦种植间隔期(6～9月份)播种一茬燕麦-豌豆混播作物,以增加本地饲草产量,提高土地利用率。试验以两批不同播种期的燕麦和豌豆混播作物的全株作物为研究对象,第一批于5月10日播种(正常时间播种),7月27日收获;第二批于6月20日播种(延后播种),9月3日收获,收获后将两批混播作物中的燕麦和豌豆分别分开处理,即得到4个样品。采用常规检测方法对不同播期的燕麦和豌豆的营养成分进行测定,并以3头装有永久性瘤胃瘘管的荷斯坦奶牛作为试验动物,采用尼龙袋法研究不同播期对燕麦-豌豆混播作物瘤胃降解率的影响。研究结果表明:①营养成分:晚燕麦(6月20日播种)和晚豌豆(6月20日播种)的粗灰分(Ash)、粗蛋白(CP)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、酸性洗涤不溶蛋白(ADFIP)、可溶性蛋白(SP)和非蛋白氮(NPN)的含量均分别显著高于早燕麦(5月10日播种)和早豌豆(5月10日播种)(P<0.05),两者的粗脂肪(EE)含量均分别显著低于早燕麦和早豌豆(P<0.05)。早燕麦的木质素(ADL)和中性洗涤不溶蛋白(NDFIP)分别显著低于晚燕麦(P<0.05),早豌豆的木质素(ADL)和中性洗涤不溶蛋白(NDFIP)分别显著高于晚豌豆(P<0.05)。②奶牛瘤胃降解试验表明,早燕麦中DM和CP的快速降解部分a值及其DM、NDF和ADF的慢速降解部分b值都分别显著高于晚燕麦(P<0.05),晚燕麦中NDF和ADF的a值都分别显著高于早燕麦(P<0.05);早豌豆中CP的b值和ADF的a值都分别显著高于晚豌豆(P<0.05),晚豌豆中CP和NDF的a值都分别显著高于早豌豆(P<0.05)。有效降解率(ED)方面,晚豌豆的DM、CP、NDF和ADF的ED值都显著高于早豌豆(P<0.05);早燕麦的DM、NDF和ADF的ED值都显著高于晚燕麦(P<0.005),两者的CP的ED值差异不显著(P>0.05)。综上所述,除DM差异不显著(P>0.05)外,早燕麦和晚燕麦其它常规营养成分含量之间差异显著(P<0.005)。晚豌豆DM、CP、NDF和ADF的有效降解率都显著高于早豌豆(P<0.005);早燕麦DM、NDF和ADF的有效降解率都显著高于晚燕麦(P<0.005),两者CP的有效降解率之间差异不显著(P>0.05)。     

肉牛营养需要量及日粮配制指南概述

文章主要以描述及表格的方式总结了美国NRC于1996年发布的第7版肉牛营养需要量的要点,尤其补充了其后研究取得的最新进展,同时简述了常用肉牛用饲料的养分特性和典型日粮中可能出现的矿物元素缺乏的情形,并指出肉牛饲料成分表中的数据特点及采用数据注意的问题。最后作者认为,只有通过软件编程和线性规划技术,集成肉牛营养需要量及饲料成分数据为日粮配方系统,并优化得到日粮生产配方,才能达到营养需要量研究及饲料营养价值评定的最终目的。     

不同沉淀方法对四倍体刺槐叶蛋白营养成分的影响

对不同加热条件和pH条件下叶蛋白的营养成分进行测定分析,结果表明:不同温度下所提取的叶蛋白中粗蛋白质含量随温度升高呈现上升趋势,65℃时粗蛋白质和磷含量达到最大,随提取温度升高粗纤维和粗脂肪含量逐渐降低;pH为2时,叶蛋白中粗蛋白质、粗脂肪分别为38.49%和8.55%,粗纤维最低仅为1.26%,而氢氧化钠处理下粗灰分、钙和磷的含量略高于盐酸处理。     

日粮添加不同油脂原料对肉牛生长性能、养分消化及瘤胃发酵性能的影响

文章旨在探讨日粮添加不同油脂原料对肉牛生长性能、养分消化及瘤胃发酵性能的影响.试验选择平均初始体重(296±32.33)kg、带有瘤胃瘘管的肉牛48头,随机分为4组,每组4个重复,每个重复3头.对照组肉牛饲喂不含油脂的日粮,处理组肉牛分别饲喂含有5％棕榈油、亚麻油和包被脂肪的日粮.在为期10周的饲养试验后测定相关指标....     

Effects of traditional Chinese medicine formula on ruminal fermentation,enzyme activities and nutrient digestibility of beef cattle

This study was conducted to evaluate effects of traditional Chinese medicine formula (TCMF) combined with several herbs on ruminal fermentation, enzyme activities and nutrient digestibility. Twenty finishing bulls were assigned to control or different TCMFs (Yufeisan‐1, ‐2, ‐3; 2.5% dry matter (DM) in concentrate). Results showed that DM intake was higher (P < 0.05) in the Yufeisan‐3 group than others. Compared to control, apparent digestibility of crude protein and neutral detergent fiber were increased (P < 0.05) by Yufeisan‐3. No changes were observed in ruminal pH, concentrations of ammonia‐N, microbial crude protein and total volatile fatty acid, whereas ratio of acetate to propionate was lower (P < 0.05) and propionate proportion tended to be higher (P < 0.1) in three TCMFs than control. Ruminal xylanase (P = 0.061) and carboxymethylcellulase (P < 0.05) activities were higher in Yufeisan‐3 than control. No changes were observed in abundance of total bacteria, fungi and protozoa, whereas Fibrobacter succinogenes (P = 0.062) and Ruminococcus flavefaciens (P < 0.05) were increased and total methanogens was reduced (P = 0.069) by Yufeisan‐3 compared to control. Yufeisan‐3 improved nutrient digestibility and ruminal enzyme activity, and modified fermentation and microbial community, maybe due to the presence of Herba agastaches, Cortex phellodendri and Gypsum fibrosum.     

双乙酸钠对苜蓿青贮品质、营养成分及蛋白分子结构的影响

为了促进节粮型畜牧业发展,为反刍动物提供优质青贮饲料。研究了添加剂(双乙酸钠)在紫花苜蓿青贮中的最佳作用剂量,通过在青贮过程中添加不同浓度的双乙酸钠,探究其对苜蓿青贮发酵品质、营养特性以及蛋白质分子结构的影响。选用6月初第一茬刈割的初花期金皇后紫花苜蓿为原料进行青贮,试验组依据双乙酸钠的添加水平设0(对照),0.1%、0.2%、0.3%、0.4%、0.5%、0.6%和0.7%共8个处理组,在常温下贮藏45 d后测定相关指标。测定结果如下:添加双乙酸钠组苜蓿青贮饲料pH值显著低于对照组(P<0.05),中性洗涤纤维和酸性洗涤纤维含量也显著降低,感官评分试验组均优于对照组。双乙酸钠添加量为0.7%时,蛋白质含量最高,丙酸、丁酸及氨态氮含量最低;酰胺Ⅰ、Ⅱ区的峰高及峰面积显著降低,α-螺旋区与β-折叠区中心高度比显著升高。这表明添加双乙酸钠能显著改善青贮苜蓿的营养特性、发酵品质以及蛋白质分子结构。综合本试验数据及经济成本考量,双乙酸钠最佳添加量为0.5%~0.6%。     

Effects of extruded flaxseed on layer performance,nutrient retention and yolk fatty acid composition

1. This study was conducted to determine the effects of feeding an extruded flaxseed (EF) on layer performance, apparent total tract nutrient retention (ATTR) and egg yolk fatty acid concentrations.

2. Seventy-two White Leghorn laying hens (58-week-old; three per cage) were randomly allotted to one of four dietary treatments: 0%, 7.5%, 15.0% and 22.5% of EF-supplemented diets for 8 weeks.

3. Supplementation with EF had no effect on feed intake, egg production, feed conversion ratio and egg weight. Egg components (yolk, albumen and shell percentages) were similar among treatments, except that shell percentage was greater for layers fed 22.5% EF than those fed 7.5% and 15% EF. The ATTR of dry matter and organic matter were highest for 0% and 7.5% EF, intermediate for 15% EF and lowest for 22.5% EF. Similar reductions on ATTR of crude protein and nitrogen-corrected apparent metabolisable energy were observed for layers fed 22.5% EF relative to those fed 0% or 7.5% EF.

4. Feeding EF at 7.5%, 15.0% and 22.5% of the diet markedly increased (by 92%, 198% and 271%, respectively) egg yolk concentrations of n-3 polyunsaturated fatty acid (PUFA) and reduced saturated fatty acid and n-6 PUFA concentrations.

5. It was concluded that omega-3 labelled eggs (300 mg/60 g of egg) may be produced with low (7.5% of diet) levels of dietary EF without compromising egg production parameters. However, feeding moderate to high levels of EF (i.e. 15% and 22.5% EF) may reduce total tract nutrient and energy utilisation.