人工唾液对绵羊瘤胃液相平衡、瘤胃发酵和微生物氮合成的影响

进行两个试验,研究灌注人工唾液对绵(?)平衡,瘤胃发酵和微生物蛋白质合成的影响。用尿液嘌呤衍生物总量作为供给宿主动物微生物氮的指标。试验1内,4只绵羊每天饲喂1kg以侧短干草为基础的配合日粮,采用4×4拉丁方(?),别向瘤胃中灌注0,1.5,3和4L/d单倍浓度的人工唾液(AS)。试验2内,3(?)每天饲喂与试验1成分相同的颗粒日粮1kg,采用3×4不完全拉丁方设计,分别(?)瘤胃中灌注0,4和8L/d单倍浓度和4L/d双倍浓度的人工唾液(DAS)。试验1发现,灌注人工唾液对瘤胃液体积、瘤胃液稀释率、发酵类型及微生物氮合成没有影响试验又发现,灌注8L/d AS和4L/d DAS显著提高瘤胃液稀释率和微生物氮的今成(P<0.05):但对瘤胃液体积没有显著影响(P<0.05)。4个处理的微生物氮合(?)效率分别为8.50,11.20,13.10和13.97g/kg可消化有机物(DOM)(S.E=(?) 95)。微生物氮合成效率与瘤胃液稀释率有相关关系。     

复合化学处理麦秸对体外瘤胃发酵参数的影响

为了研究复合化学处理麦秸对体外瘤胃发酵参数的影响,试验采用2因素3水平完全交叉试验设计,将尿素和氢氧化钙均按麦秸干物质质量2%、3%和4%的量分别添加,共9个试验组,1个对照组(原麦秸),通过短期人工瘤胃技术研究不同水平尿素和氢氧化钙处理麦秸对瘤胃液pH、氨氮(NH3-N)质量浓度、微生物蛋白(MCP)产量和挥发性脂肪酸(VFA)质量浓度的影响。结果表明:不同水平尿素和氢氧化钙处理麦秸对瘤胃液pH影响不显著;对NH3-N质量浓度影响显著或极显著,但均在正常范围内;在MCP产量方面,8、9和10组极显著高于对照组及2、3、4、5、6和7组,分别比对照组高33.73%、34.94%和31.33%,8、9和10组3个组间无显著差异;在乙酸、丙酸和丁酸3种VFA总质量浓度上8、9和10组极显著高于对照组和其余6个试验组,比对照组分别高73.55%、76.50%和64.24%,8组和9组显著高于10组,且无显著差异。在试验设计条件下,尿素和氢氧化钙复合处理麦秸时最适宜的添加水平分别为其干物质质量的4%和2%。     

硫酸钠对奶牛瘤胃发酵的影响

本文旨在研究不同添加水平的硫酸钠对泌乳中期奶牛瘤胃发酵的影响。试验选用4头体重、胎次、产奶量均相近的荷斯坦奶牛,采用4×4拉丁方设计,试验分4个处理组,添加不同水平的硫酸钠,即0%(对照组)、0.4%(试验1组)、0.8%(试验2组)与1.2%(试验3组),试验分为4期,每期18 d(预试期15 d,正试期3 d)。结果表明:(1)饲粮中添加硫酸钠对瘤胃液pH、NH3-N平均浓度无显著影响(P>0.05);(2)饲粮中添加硫酸钠后,瘤胃内原虫数均有所提高,其中试验2组和试验3组与对照组相比均差异显著(P<0.05);(3)添加硫酸钠的试验2组瘤胃液菌体蛋白浓度与对照组相比显著提高(P<0.05)。结果说明,日粮中添加适量的硫酸钠可以改变瘤胃发酵环境,提高瘤胃液菌体蛋白浓度。     

饲粮氮硫比对藏羔羊瘤胃发育及微生物菌群结构和功能的影响

本试验旨在研究饲粮氮硫比对藏羔羊瘤胃发育及瘤胃微生物菌群结构和功能的影响。选取初始条件相似的60日龄断奶藏羊羔羊150只,随机分为5组,每组30只。各组饲粮的氮硫比分别为10.5∶1.0(A组)、9.0∶1.0(B组)、7.5∶1.0(C组)、6.0∶1.0(D组)、4.5∶1.0(E组)。预试期5 d,正试期120 d。试验结束时,每组随机屠宰6只,采集瘤胃组织和瘤胃内容物,分析饲粮氮硫比对瘤胃组织形态和瘤胃液挥发性脂肪酸(VFA)含量以及瘤胃细菌群落结构及其功能的影响。结果显示:1)B组瘤胃乳头长度、黏膜下层厚度以及肌层厚度显著高于其他4组(P 0.05),B、C、D组瘤胃乳头宽度显著高于A、E组(P0.05),B、E组瘤胃乳头密度显著高于其他3组(P0.05),C组瘤胃角化层厚度显著高于其他4组(P0.05)。2)B组瘤胃液总挥发性脂肪酸(TVFA)、乙酸、丙酸、丁酸、异丁酸含量显著高于其他4组(P0.05)。3) B、C组Shannon指数显著高于A组(P0.05),A组Simpson指数显著高于其他4组(P0.05),B组Chao1指数和ACE指数显著高于其他4组(P0.05)。4)各组的优势菌门均为为厚壁菌门(Firmicutes),A组厚壁菌门相对丰度显著高于C组(P0.05)。各组的优势菌科均为毛螺菌科(Lachnospiraceae)、克里斯滕森氏菌科(Christensenellacea)、韦荣氏球菌科(Veillonellaceae)、瘤胃球菌科(Ruminococcaceae),D组毛螺菌科相对丰度显著高于A、B、E组(P0.05),A组韦荣氏球菌科相对丰度显著高于C、D组(P0.05)。5)功能预测分析结果显示,瘤胃内菌群功能主要集中在碳水化合物代谢和氨基酸代谢。综上所述,饲粮氮硫比为9.0∶1.0时瘤胃组织形态发育较好,瘤胃液中VFA含量较高,瘤胃微生物的相对丰度及多样性较高。因此,饲粮氮硫比为9.0∶1.0更能经济有效地促进瘤胃发育和改善羔羊瘤胃微生物区系结构。     

无机硫来源对体外瘤胃发酵的影响

利用短期人工瘤胃发酵装置,研究精粗比为4∶6日粮添加硫磺、硫酸钠、硫化钠等三种来源的硫对瘤胃液pH、挥发性脂肪酸(VFA)产生量的影响.结果表明:硫的添加量明显影响人工瘤胃发酵中有机物的消失率(P<0.05),日粮中添加硫0.5%时,对照组、硫磺、硫酸钠、硫化钠组间瘤胃液pH、日粮中性洗涤纤维(NDF)消失率、氨态氮浓度有明差异(P<0.05),硫来源没有明显影响人工瘤胃中总VFA、丙酸、乙酸浓度(P>0.05);硫酸钠、硫化钠的作用效果优于硫磺试验组.     

甘露寡糖、果寡糖和大豆寡糖组合对锦江黄牛瘤胃液细菌多样性的影响

本试验旨在研究功能性寡糖(甘露寡糖、果寡糖和大豆寡糖)组合对锦江黄牛的瘤胃液细菌多样性的影响.选择3头健康且体重相近的安装有永久性瘤胃瘘管的锦江黄牛,采用自身对照方法,试验分2期进行,第1期:对照期,饲喂基础饲粮,不添加任何寡糖;第2期:添加期,饲喂基础饲粮+功能性寡糖(0.8％甘露寡糖+1.0％果寡糖+0.8％大豆寡糖),每期持续14 d.利用PCR-变性梯度凝胶电泳(DGGE)方法研究分析牛瘤胃液细菌多样性.结果表明:添加功能性寡糖组合后,牛瘤胃液细菌PCR-DGGE图谱条带数明显增加,3头牛增加了5个共同条带.经测序,其中2个是产琥珀酸丝状杆菌属,3个是未鉴定细菌.饲粮中添加功能性寡糖组合可使瘤胃液细菌菌群种类明显增加.结果提示,饲粮添加功能性寡糖组合能够影响瘤胃菌群区系,增强其稳定性.     

日粮中添加玉米油对肉牛瘤胃发酵的影响

3头装有瘤胃瘘管的成年杂种牛 ,按 3× 3拉丁方试验设计 ,饲以添加 0 %、4 %和 8%玉米油的稻草和精料混合料 ( 2 1 )日粮。在饲喂后 2、4、6、8h采集瘤胃液样品 ,分别测定瘤胃液pH值、NH3-N和VFA浓度。结果表明 ,添加 4 %和 8%玉米油对瘤胃液pH值、NH3-N浓度没有显著影响 (P >0 .0 5) ;添加玉米油 4 %对瘤胃总VFA浓度没有显著影响 (P >0 .0 5) ,但添加 8%玉米油使瘤胃总VFA和乙酸浓度显著下降 (P <0 .0 5)。添加 8%以下的玉米油对丙酸、丁酸浓度没有影响 (P >0 .0 5) ,结果使乙酸 /丙酸比值从 3.75分别下降到 3.2 6和 3.1 4 (P <0 .0 5)。     

绵羊瘤胃乙酸﹑丁酸产生量的提高对其消化道吸收和流通的影响

本试验旨在研究基础饲粮条件下绵羊瘤胃乙酸、丁酸产生量的提高对其消化道吸收流通的影响。选用体况良好、1.5岁左右、体重相近的安装有永久性瘤胃瘘管和近端十二指肠瘘管的内蒙古半细毛羯羊6只,随机分为2组,每组3只,一组为乙酸灌注组,另一组为丁酸灌注组。每组设置3个处理,每个处理代表1个灌注的乙酸﹑丁酸水平及1次启动-连续灌注试验。试验通过模拟连续饲喂从而获得瘤胃稳态条件,采用非同位素标记乙酸、丁酸溶液灌注技术进行测定。结果表明:1)随着瘤胃乙酸产生速率的提高,瘤胃pH、瘤胃乙酸吸收率显著下降(P 0.05),瘤胃乙酸浓度、乙酸吸收速率和乙酸流通速率极显著上升(P0.01),瘤胃液相钴(Co)浓度、瘤胃液相小时稀释速率、液相流通速率和液相体积均无显著变化(P0.05);瘤胃丁酸产生速率的提高除了对瘤胃液相Co浓度也影响显著(P0.05)外,对其他指标影响同乙酸处理的变化。2)随着瘤胃乙酸产生速率的提高,各试验羊乙酸十二指肠流通速率逐渐增加(2. 95～3.47 mmol/h),但各水平间差异不显著(P0.05);进入十二指肠的乙酸占进入后消化道总乙酸的比例(5. 68%～3. 35%)极显著下降(P 0. 01);乙酸在瓣胃﹑真胃的吸收比例(94. 32%～96.65%)极显著上升(P0.01)。本研究条件下,绵羊瘤胃乙酸、丁酸产生速率的增加提高了其瘤胃浓度,降低了瘤胃pH,提高了其瘤胃吸收速率和瘤胃、十二指肠流通速率,但瘤胃吸收效率下降。     

苜蓿皂苷对体外发酵pH值、氨氮及微生物蛋白浓度的影响

试验采用体外培养法研究了日粮中添加苜蓿皂苷对山羊瘤胃微生物发酵功能的影响.苜蓿皂苷的添加水平分别为底物基础的0%(对照组)、1%、2%、3%及4%.结果表明:日粮中添加苜蓿皂苷未对瘤胃液pH值和原虫蛋白浓度产生显著影响;添加苜蓿皂苷可提高氨氮浓度,但仅4%组增幅达显著水平(P＜0.05);4%组细菌蛋白浓度显著高于对照组(P＜0.01),其余各组间差异不显著(P＞0.05).结论:在本试验条件下,苜蓿皂苷添加量为0%～4%时均不影响瘤胃液pH值和原虫蛋白浓度.添加4%的皂苷是可显著提高NH3-N和细菌蛋白浓度.     

日粮不同CP及RUP水平对奶牛瘤胃发酵的影响

试验旨在研究不同水平的粗蛋白(CP)及瘤胃非降解蛋白(RUP)的日粮对奶牛瘤胃代谢的影响。试验选择18头健康、体重相近的荷斯坦奶牛作为试验动物,随机分为6组,每组3头。采用2×3因子完全随机试验设计,其中CP设7.5%(低)、9.0%(中)、10.5%(高)3个水平,RUP设45%CP(低)、55%CP(高)2个水平,共6个处理组,饲喂相同基础日粮,精粗比为3∶7,预饲期10d,饲喂后2、4、8、12、24h从食道采集瘤胃液2d,测定瘤胃液pH值,NH3-N、微生物蛋白质(BCP)、挥发性脂肪酸(VFA)含量。结果表明,日粮CP水平对瘤胃液NH3-N浓度的影响极显著(P<0.01),对BCP及VFA的含量影响较小,总体而言,9.0%CP水平组对奶牛的瘤胃发酵略好于其他两组;日粮中高RUP(55%CP)可以显著降低瘤胃pH值且有降低NH3-N浓度的趋势,同时,对瘤胃BCP及VFA的合成有一定的促进作用。该试验条件下,日粮中CP(9.0%)和RUP(55%CP)可在一定程度上改善瘤胃代谢。     

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.     

Ticks on crested francolins, Francolinus sephaena, and on the vegetation on a farm in Limpopo Province, South Africa

Ticks were collected at approximately bi-monthly intervals between June 1996 and June 1997 from crested francolins, Francolinus sephaena, and from the vegetation on a mixed cattle and wildlife farm in Limpopo Province, South Africa. The birds were infested with the immature stages of 13 tick species, of which Amblyomma hebraeum, Amblyomma marmoreum and Hyalomma marginatum rufipes were the most numerous and prevalent. Ten ixodid tick species were collected from the vegetation, of which the immature stages of Rhipicephalus appendiculatus, Rhipicephalus (Boophilus) decoloratus and Rhipicephalus evertsi evertsi were the most numerous. No adult ticks were collected from the birds and only two from the vegetation. The restricted home range of crested francolins implies that they could serve as a source of tick infestation only for other animals within the same habitat as the birds.     

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.     

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.