青藏高原高寒草甸草场土-草-畜生态系统中钠、钾的季节变化研究

本试验对青海省三角城种羊场土壤-牧草-绵羊生态系统中6、9、12月份常量矿物元素钾、钠进行了调查研究。结果表明:①9月份试验点土壤钠含量最高(13．88 g/kg),土壤速效钾含量最低(0．21 g/kg);②牧草中钠在幼嫩期 (6月份)含量最高(5．77 g/kg),在生长末期(9月份)含量最低;而钾在牧草生长末期(9月份)最高(5．96 g/kg),在枯草期(12月份)含量最低;③钾元素在9、12月份出现负沉积,3期中日采食量均低于需要量;血液中钠、钾含量均低于正常值,唾液中钠钾比在6月份和9月份均低于正常值。     

四川阿坝县秋季牧草钙磷等矿物元素特征及其与土壤钙磷含量的关系

采用常规方法测定了四川阿坝县4个不同牧场秋季(9月)牧草矿物元素含量及土壤中的钙磷含量,以期为该地区反刍动物的放牧饲养提供依据。结果表明:阿坝县4个地区秋季牧草矿物元素中钙、钠和锌的含量差异不显著,磷、铁、铜、钾、镁、锰和硒含量差异显著(P<0.05),其中磷、锌和硒的含量不能满足反刍家畜的营养需求,需要补饲;土壤中钙含量差异不显著,全磷和有效磷差异显著(P<0.05);牧草中的钙、磷含量与土壤中钙、磷含量之间没有显著的相关性。     

青海三角城种羊场高寒草甸草场氮、硫的季节变化及其盈缺分析

对青海省三角城种羊场高寒草甸草场夏 (6月中旬 )、秋 (9月中旬 )、冬 (12月中旬 )三季的土壤、牧草、绵羊血液中的氮 (N)、硫(S)元素含量进行了采样调查。分析结果表明 :土壤有效硫 [(0 5 6± 0 3 7～ 0 97± 0 2 7)g/kg]能满足牧草的需要 ,可食牧草硫含量[(1 60± 0 43～ 2 81± 0 19)g/kg]在正常范围内 ,9月份 [(1 67± 0 2 6)g/kg]牧草生长末期和 12月份 [(1 60± 0 43 )g/kg]牧草枯草期含硫量处于低期水平 ,不能满足生长羊的需要 ;土壤全氮 [(0 2 3± 0 0 4～ 0 3 0± 0 0 1) % ]和碱解氮 [(0 0 7± 0 0 18～ 0 10± 0 0 2 )g/kg]均在正常范围之内 ;12月份可食牧草中氮含量 [(11 0 2± 4 5 3 )g/kg]、绵羊血清白蛋白 [(2 5 2 1± 1 0 9)g/L]和氮硫比 (6 89∶1)均低于正常值 ;说明 12月份牧草中含氮量不能满足绵羊需要     

不同季节牧草钙磷含量对放牧绵羊血清降钙素的影响

研究了不同季节牧草钙、磷含量对放牧绵羊血清降钙素、碱性磷酸酶、血清钙、无机磷、血清钙磷比和血清钙磷乘积的影响,发现这些血清指标随季节变化明显。血清降钙素夏季时的含量为(184.627±117.224)ng/L,极显著的低于秋季时的含量(571.317±254.337)ng/L(P<0.01),但是与冬春季的含量(345.583±311.591)ng/L差异不显著(P>0.05),并且冬春季血清降钙素含量与秋季含量差异也不显著。从相关分析得出,降钙素与牧草钙,磷和钙磷比呈负相关,相关系数为-0.147,-0.234和-0.106,但是相关性不强。该地区在3季内,牧草能够满足放牧绵羊对钙的需要,但是不能满足对磷的需要(除夏季外),因此,引起钙、磷从骨骼中动员,使得血清降钙素、碱性磷酸酶等血液指标发生变化。应为该地区加强补饲,避免由钙磷缺乏引起的生产力下降。     

犬的钙、磷营养研究进展

钙和磷是犬体内必需的常量矿物元素,也是犬配合饲料中的重要营养素。犬对钙、磷的需要量与畜禽存在很大的差异。日粮中钙和磷的含量、比例都会影响机体钙、磷代谢状况。不同品种不同生命阶段的犬,对钙、磷的最小需要量和适宜供给量有很大差异。文中从钙、磷的生理功能,犬对钙、磷的吸收率,犬的钙、磷需要量等方面进行了综述。     

猪的钙磷需要

一、饲养标准里的钙磷需要量《养猪》杂志1990年第4期在“猪对常量无机元素的需要”一文中,已介绍了美、英、德、苏四国最新钙磷需要量(占饲粮％)。日本(1987)规定量与美国基本相同,仅生长猪划分20—35,35—70,70—110千克三级。以美、日为最低。对比美国科委(NRC)颁布的1973、1979与1988年三个版本。     

青藏高原东北缘放牧草地土壤矿物元素含量及分布特征

为科学评价放牧草地土壤矿物元素含量、分布特征以及对土-草-畜矿物生态系统的潜在影响,对青藏高原东北缘的4个县(天祝、大通、玛曲、若尔盖)的土壤特征和矿物元素进行分析调查。共计采集256个来自该地区不同土壤类型(高山草甸土、亚高山草甸土、沼泽土)的表层土壤样品,分析了土壤中11种矿物元素的有效含量(Ca、P、S、K、Mg、Na、Fe、Mn、Zn、Cu和Co)和2种矿物元素(Mo和Se)全部含量。分析发现,土壤中多数矿物元素含量随着地区和土壤类型的不同而表现出一定的差异性,土壤中多数矿物元素含量与土壤有机碳和全氮呈显著正相关,相反与土壤pH有一定的负相关性。土壤中矿物元素磷和镁的有效含量均低于动物可能出现缺乏的临界值,土壤中全量硒的含量严重低于动物硒缺乏的临界值。土壤中磷、镁、硒的缺乏可能会引起该地区放牧家畜该矿物元素缺乏。另外,土壤中元素铁的有效含量远高于推荐值,土壤铁的含量过高可以引起牧草中铁的含量上升,进而影响家畜对其他元素的吸收。然而,要确认家畜是否存在该类矿物元素缺乏和不平衡问题,还需要进一步分析该地区牧草和家畜组织矿物元素含量以及家畜的生产力水平。     

东北农牧交错带小尾寒羊集群放牧系统中钙、磷元素营养状况分析

对我国东北农牧交错带内小尾寒羊集群放牧生态系统中5、7、9月钙、磷元素的营养状况进行了分析。结果表明:牧地土壤中钙、磷元素的总平均含量分别为1.46%、178.88μg/g;小尾寒羊2种主食牧草中钙、磷元素的总平均含量分别为0.39%、256.26μg/g;小尾寒羊羊毛中钙元素的总平均含量为2111.45μg/g;小尾寒羊羊血中钙、磷元素的总平均含量分别为69.65μg/g、10.21μg/g;小尾寒羊羊骨中钙、磷元素的总平均含量分别为4.44%、2.45%。据此认为,在该交错带集群放牧的小尾寒羊不会发生钙缺乏症或中毒病,但可能发生磷缺乏症。     

35～50kg道赛特×小尾寒羊杂交公羔矿物质需要量研究

本试验旨在研究35~50 kg道赛特×小尾寒羊杂交公羔钙、磷、钾、钠、镁的维持需要量和净生长需要量。选取(34.54±0.40)kg、6月龄道赛特×小尾寒羊杂交公羔25只分为5组,初期组,中期组,末期100%组、末期60%组、末期40%组(饲喂水平分别为100%、60%、40%),初期组、中期组、末期组分别在羔羊体重为35、43和50 kg时屠宰。测定动物体组织中的钙、磷、钾、钠、镁含量,建立数学模型对矿物质的维持需要量和净生长需要量进行预测。结果显示:道寒杂交公羔在35~50 kg体重阶段,钙、磷、钾、钠、镁的维持需要量分别为0.73、0.72、0.32、0.32、0.13 g/d,基于空腹体重(EBW)的净生长需要量分别为13.47~14.00 g/kg EBW、7.18~7.41 g/kg EBW、0.13~0.17 g/kg EBW、1.20~1.73 g/kg EBW、0.45~0.58 g/kg EBW。本研究得出了35~50 kg道赛特×小尾寒羊杂交公羔矿物质维持需要量和净生长需要量的模型。     

西藏那曲地区高寒草地牧草矿物元素动态变化及盈缺分析

测定了那曲地区尼玛县高寒草地不同月份围栏内和围栏外牧草矿物元素（Ca、P、Na、K、Mg、Cu和Zn）含量，并根据元素的吸收率及藏山羊矿物元素需要量，对放牧藏山羊采食牧草中矿物元素的盈缺进行了分析。结果表明：同月份围栏内与围栏外的矿物元素含量差异不显著（P〉0．05），但不同季节的变异很大。夏秋季牧草Ca、P、Na、K、Mg、Cu、Zn的含量（Ca1．25％DM，P0．1419％DM，Na0．06％DM，K1．51％DM，Mg0．28％DM，Cu8．70mg／kg，Zn27．35mg／kg）高于冬春季（Ca0．72％DM，P0．0005％DM，Na0．02％DM，K0．43％DM，Mg0．10％DM，Cu3．02mg／kg，Zn8．49mg／kg）。除Mg和青草期的K能满足藏山羊的需要外，其余元素不能满足藏山羊生长、繁殖和泌乳对矿物元素的需要量。     

Knowledge,attitude, and practices on usage,disposal, and effect of plastic bags on sheep and goats

The objective of this study was to evaluate knowledge, attitudes, and practices of people in the Nairobi and Kajiado Counties, Kenya, on the usage, disposal, and effect of plastic waste on sheep and goats (shoats). A semi-structured questionnaire was used to collect data from 384 respondents in four communities in the two counties. Most of the people irrespective of their age, occupation, and educational status used plastic bags of some type on a daily basis. A high proportion of the respondents (37.0%, 142) used plastic bags because of the low cost. Approximately, 79.1% (304) disposed used plastic bags in open dumps. A total of 147 (38.3%) households kept shoats. Out of these, 38.1% (56) purchased feed and also allowed their animals to roam. Most of them (45.3%, 174) thought that lack of feed for the animals was the main reason why shoats roam and scavenge at refuse dump sites and road sides. A large proportion of the respondents (44.5%, 143) mentioned death of animals as the ultimate consequence of ingestion of waste plastic bags. Though, the respondents were aware that indiscriminate disposal of used plastic bags could result in death of the animals from which they derive their livelihoods, they nevertheless continued with the practice. There is a need for a paradigm shift in the way and manner plastic bags are used and disposed.     

Effects of sire growth potential, growing-finishing strategy, and time on feed on performance, composition, and efficiency of steers.

Beef production systems that increase use of unharvested forages and use animals with greater potential for gain affect age and size of animals placed on a finishing regimen. This experiment was conducted to evaluate effects of genetic potential for gain, age at the start of a finishing period, and time on feed on composition, quantity, and quality of beef produced and efficiency of production during finishing. Crossbred cows were bred by AI to Charolais or Line 1 Hereford bulls that represented potentially high (HG) or moderate growth (MG) rates, respectively, to produce spring- or fall-born calves. Steer calves from these matings were placed on an individually fed finishing diet at three ages (A). Spring-born steers were started at 6 or 18 mo of age (A6 and A18), and fall-born steers were started at 12 mo of age (A12). Slaughter times (T) were at 0, 90, 180, and 270 d for A6; 68, 136, and 204 d for A12; and 0, 45, 90, and 135 d for A18. Data collected on each animal included feed intake, growth, chemical composition of the complete body and carcass, and quantitative and qualitative assessment of the meat produced. Four steers of each sire group were slaughtered in each of the 11 A-T treatment groups, and the experiment was repeated for 2 yr in the A12 groups and 3 yr in the A6 and A18 groups (n = 237). Steers sired by HG bulls were larger and produced larger carcasses and more carcass protein than MG-sired steers (S, P < .05 or .01). Steers sired by MG bulls were fatter, had higher quality grades, and accumulated fat at a faster rate than HG-sired steers, and this effect was greater in older steers (G and GA, P < .05 or .01). Sire growth potential did not affect gain, intake, live weight efficiency, tenderness, or taste panel scores (P > .2). Steers sired by HG bulls were more efficient at producing carcass weight and carcass protein at A12 and A18 than were MG-sired steers. At the end of the finishing period, older (A18), HG-sired steers were too large with insufficient fat by current industry standards, and younger (A6), MG-sired steers were too small. Our conclusions are that both HG- and MG-sired steers can produce acceptable carcasses for current market standards with comparable efficiencies of live-weight gain, but the growing and finishing strategy must be adapted to the genotype.     

Effect of feeding corn naturally contaminated with aflatoxin on feed efficiency, on physiologic, immunologic, and pathologic changes, and on tissue residues in steers

Two of 3 groups of Holstein-Friesian steers (groups II and III; n = 5 each) were fed a ration containing corn naturally contaminated with 800 ng of aflatoxin/g. The other group of steers (group I; n = 5) was fed a ration containing noncontaminated corn. The respective rations were fed for 17.5 weeks, except the ration given to group III; the latter's first diet (contaminated with aflatoxin) was changed to a noncontaminated diet after 15 weeks, continuing for the remaining 2.5 weeks. All steers were killed and tissues and fluids were obtained for aflatoxin analysis. Although aflatoxin B1 and M1 could be detected in blood and urine at several sampling times during the experimental period in groups II and III steers (given the diets containing aflatoxin), there appeared to be no effects on body weight gains and immune phenomena, such as lymphoblastogenesis and antibody production, but there was a waning of the delayed cutaneous hypersensitivity in steers given aflatoxin-contaminated diets. In group III animals (diet was changed to noncontaminated ration at 15 weeks), aflatoxin B1 and M1 disappeared from urine before they were slaughtered. All tissues and fluids, except the rumen contents from these group III steers, were void of detectable aflatoxins B1 and M1 at necropsy. The concentrations of aflatoxin B1 in the rumen content of the latter steers were low. All tissues collected at necropsy from the group II steers fed the aflatoxin diet throughout the 17.5 weeks had detectable aflatoxins B1 or M1 present.     

葡萄糖、果糖、聚乙烯醇及牛磺酸对山羊精液保存的影响

以Androhep稀释液为山羊精液液态保存基础稀释液,研究了葡萄糖和果糖,聚乙烯醇(PVA)含量,及牛磺酸的添加量对5℃保存山羊精液的影响.结果发现,Androhep稀释液中以只含葡萄糖保存效果最好,PVA的量以0.5%为最佳,牛磺酸添加21 mmol/L时保存6 d精子的活力和质膜完整率最高.     

发酵乳中SOD、CAT、GSH-Px、GST活性的变化

10份鲜牛乳98℃煮沸5min后,用乳酸菌发酵制作酸乳。测定了发酵前后乳中SOD、CAT、GSH-Px、GST的变化。发酵前4种酶的活性分别为:45.68±7.81、1.46±1.78、156.67±37.51(GSH-PX活力单位),65.81±25.47;发酵后各酶的活性分别为73.47±5.27、0.44±0.50、0、5.42±3.25。发酵乳SOD活性升高60%多,CAT降低近73%,GST降低近92%,GSH-Px活性全部丧失(P<0.01)。