富硒铜锌牧草对奶牛抗氧化功能的影响

利用富含硒、铜、锌、锰牧草喂饲处于亚临床微量元素不足的奶牛,研究奶牛血中硒、铜、锌、锰元素含量及抗氧化指标的变化。结果表明：奶牛血中铜、锌、硒元素含量有显著的增加,血清GSH-Px、SOD、CP、T-AOC等抗氧化指标有较明显的提高。     

叶面喷施微肥对牧草、奶牛微量元素代谢的影响

试验采用含硒、锌、铜、锰等元素的微肥对牧草进行叶面施肥，研究通过这种施肥途径对牧草品质的影响。同时采用此种牧草饲喂奶牛，研究这种牧草对奶牛血液中相应元素含量及奶牛生产水平的影响。结果表明，牧草中硒、锌、铜、锰的含量有显著的提高；奶牛采食这种牧草90d后，血液中硒、锌、铜的含量显著提高，生活水平有所增长。     

农户舍饲奶牛血清钙及游离羟脯氨酸水平测定

采用氯胺T比色法和EDTANa_2滴定法,对重庆市农户舍饲奶牛不同泌乳阶段血清中游离羟脯氨酸与血清钙的水平进行 测定,旨在调查试验条件下奶牛血钙代谢情况以及骨营养不良发生的可能性。结果显示: 在农户全舍饲条件下,血清钙含量Ⅱ组显著低于Ⅴ组、Ⅵ组,其它各组间差异不显著;Ⅰ～ Ⅵ组血清羟脯氨酸含量分别为2.32±0.37μg/ml、2.36±0.59μg/ml、2.02±0.54μg/ml、1.90±0.44μg/ml、1.98±0.45μg/ml、1.79±0.18μg/ml,Ⅰ、Ⅱ组与Ⅵ组差异极显著。采样后2-3个月内进行临床观察,血清游离羟脯氨酸水平与骨营养不良发生率呈现一致性变化。而钙磷摄入不足,比例不当是主要原因。     

壳聚糖对奶牛血清钙、磷和羟脯氨酸含量的影响

选择40头中国荷斯坦奶牛，随机分为对照组和试验1、2、3四个组。每头每天分别在各组日粮中加入0g、2g、4g和6g壳聚糖，连续饲喂35d。每周测定一次血清钙、磷和羟脯氨酸的含量。结果奶牛血清钙和羟脯氨酸的含量差异不显著(P＞0．05)，添加6g/d壳聚糖，血清磷在4周后显著升高(P＜0．05)。表明：壳聚糖不影响奶牛血清钙和血清羟脯氨酸的含量。在日粮中添加6g/d壳聚糖4周以后，有利于促进机体对磷的吸收。     

氟中毒对鸡体内羟脯氨酸代谢的影响

为探讨氟对鸡体内羟脯氨酸代谢的影响,选取４００只１日龄蛋鸡,随机分为４组,每１００只。每Ⅰ组为正常对对照组,Ⅱ、Ⅲ、Ⅳ组在饲料中添加不同水平的氟化钠,使日粮中氟的呈分别为３００,６００,１２００ｍｇ／ｋｇ,实验期为１６０ｄ。定期采集血样,测定血清中氟和羟腈氨酸的含量,进行临床观察。结果表明,成功地复缺点出了鸡慢性氟中毒模型;氟中毒定期采集血样,测定血清中氟和羟腈氨酸的含量均高于对照组,且血清中氟含     

上海部分牧场高产奶牛血清锌铜铁平均值测定

微量元素对生命现象有巨大的影响。在牛的生长、发育、繁殖、生产、衰老甚至生命、死亡的各个阶段都起着十分重要的作用。奶牛对必需微量元素的缺乏或不平衡都会产生复杂的综合反应,出现各种疾病,并影响调节生命活动的各个环节,结果使幼畜生长发育缓慢,成年家畜生产力和繁殖力降低,带来较大的经济损失.我国地域宽广,土壤中微量元素含量不均衡,各地之间差异很大。土壤中微量元素的有无与多少直接影响饲料中各种微量元素的含量。美国 NRC资料报道,饲料中无机成分的差异可达±30%.奶牛的饲料主要是植物性的,这对奶牛体内微量元素含量水平影响较大.上海地区奶牛的饲料来源较广,变动大,由于测定奶牛饲料中的各种微量元素含量有一定难度,故而测定奶牛血清中的必需微量元素具有实际意义.     

牧草品质对奶牛安全健康生产的影响

饲养健康的奶牛并生产安全质优的牛奶,除了精饲料的适宜补充外,牧草品质在奶牛生产潜力发挥方面所起的重要作用不容忽视。在奶牛生产中,尚需深入了解牧草品质对产奶量、牛奶品质、繁殖率、健康安全及经济效益等的影响。     

优质牧草对奶牛养殖的影响

奶牛的特殊消化结构和功能,决定了奶牛以食草为主。但是有些养殖场往往忽略了这点,更重视精料的饲喂,这样反而对奶牛的产奶性能及健康造成了不利的影响。因为奶牛作为反刍动物,能够高效的利用牧草中的纤维成分作为营养和能量的来源满足产奶所需,所以奶牛的养殖要注重优质牧草的使用,合理搭配粗精料的饲喂比例。     

人工种植乐食牧草对奶牛产奶量的影响

乐食，原产于澳大利亚，是一种高品质、高产量的牧草新品种。2003年3月受西安市种子公司的委托．我区首次引入乐食牧草，于2003年5月20日在任留乡南韦村小范围进行种植，8月1日-8月10日进行奶牛饲喂试验，获得了明显的增奶效果，试验结果报告如下：     

热应激对奶牛血液中内毒素含量和抗氧化指标的影响

选用16头健康的中国荷斯坦奶牛,随机分为两个处理（夏季组和冬季组）,每个处理8个重复,每个重复1头牛。当夏季组奶牛牛舍温湿度指数（THI）〉72的时间连续达到15d,冬季组牛舍THI〈72的时间连续达到15d时,颈静脉采血15mL制备血清,检测血清中内毒素、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）的活性,以及丙二醛（MDA）的含量。结果表明：夏季热应激可导致奶牛血清内毒素、MDA含量极显著升高,SOD和GSH-Px活性极显著和显著（P〈0.05）下降。     

Tuberculosis and brucellosis prevalence survey on dairy cattle in Mbarara milk basin (Uganda)

We determined the prevalence of tuberculosis and brucellosis reactors in the dairy herds in the Mbarara district of Uganda in 2002. This is one of the most important dairy-production areas of the country and includes both pastoral and agro-pastoral zones. A total of 340 (of 11,995) randomly selected herds were tested for tuberculosis, using the intradermal tuberculosis-skin test and 315 (of 10,562) herds tested for brucellosis using the serum Rose Bengal test.

The herd prevalence for tuberculosis reactors was 74.1% (95% confidence intervals 69, 78), the individual-animal prevalence was of 6.0% (5.6, 6.5) and within-herd range was 1–50% (up to 100% if suspicious reactors were included).

The herd prevalence for brucellosis was 55.6% (50, 61.2) individual-animal prevalence 15.8% (14.8, 16.7) and within-herd range 1–90%.

The reactor prevalence increased with the age of the animals for both tuberculosis and brucellosis.

Tuberculosis reactor prevalences were higher in animals from the agro-pastoral zone. However, the individual-animal and herd prevalences of brucellosis seroprevalences were higher in the pastoral zone.     

Prevalence and risk factors for Coxiella burnetii (Q fever) in Dutch dairy cattle herds based on bulk tank milk testing

Despite cattle herds can harbor Coxiella burnetii, risk factors for C. burnetii presence in dairy cattle herds are largely unknown. Therefore, C. burnetii herd prevalence and risk factors for bulk tank milk (BTM) positivity were investigated. In this cross-sectional study, a questionnaire was filled out by the farmer and BTM from 301 farms was tested by ELISA for presence of C. burnetii antibodies and PCR for presence of C. burnetii DNA. Risk factors were identified by univariable and multivariable logistic regression analyses. Antibodies to C. burnetii were detected in 81.6% (CI: 77.2–85.9) and C. burnetii DNA in 18.8% (CI: 14.4–23.1) of the BTM samples. Herd size (OR = 1.1 per 10 cows), cleaning the bedding of the cubicles at most every other day (OR = 2.8) and purchase of cattle from at least two addresses (OR = 3.1) showed a significant and positive association with ELISA positivity and use of an automatic milking system a negative association (OR = 0.3). Risk factors for PCR positivity were purchase of cattle from at least two delivery addresses (OR = 3.2), presence of cows with ticks (OR = 2.0), use of an automatic milking system (OR = 0.2) and presence of goats or sheep on the farm (OR = 0.4). Biosecurity and general hygiene seem associated with introduction and spread of C. burnetii in dairy herds.     

The effect of quality of grass and maize silage on the intake and performance of beef cattle

A study was undertaken to evaluate the effects of incorporating high (HMS) and low (LMS) maturity maize silages into diets based on low (LGS) and high (HGS) feed value grass silages offered to beef cattle. Seventy-two continental cross-bred steers were used in a 14-week continuous design, randomised block experiment. The six treatments were arranged as a 2 × 3 factorial design incorporating the LGS and HGS offered as the sole forage, along with each of the two grass silages offered in a 60:40 ratio (DM basis) with the HMS and LMS. All diets were supplemented with 3 kg/head/day concentrates. Total daily DM and metabolisable energy intakes were higher (P < 0.001) for diets based on HGS compared to those based on LGS. Intakes were similar (P > 0.05) between diets containing LMS and HMS, both of which were higher (P < 0.001) than diets containing grass silage as the sole forage. Highest DM intakes were recorded with a mixture of HGS and HMS (P < 0.05 or greater). Cattle offered diets containing HGS had higher live-weight gain (P < 0.05), final live weight, carcass gain and carcass weight (P < 0.001) than those offered diets containing LGS. Feed conversion efficiency, assessed on a carcass gain basis, was poorer (P < 0.05) with diets containing LGS compared with those containing HGS, though differences between diets containing either LMS or HMS and GS as the sole forage were not significant (P > 0.05).     

Relationship between the timing of insemination based on estrus detected by the automatic activity monitoring system and conception rates using sex-sorted semen in Holstein dairy cattle

We investigated the optimal timing of artificial insemination (AI) for achieving pregnancy according to the onset/end of estrus detected by an accelerometer system in Holstein cattle. The conception rates of conventional semen were used as a reference. The conception rate from AI of sex-sorted semen was higher at −4 to 4 h (57.1%) from the end of estrus than those at −12 to −4 h (37.7%) and 12–20 h (30.3%), whereas AI at 4–12 h showed an intermediate conception rate (47.4%). Conversely, conception rates were similar in AI performed between 0 and 32 h from the onset of estrus. Regarding conventional semen, the interval from the onset and end of estrus did not affect conception rates. The present results suggest that the time of the end of estrus is the better indicator of optimal AI timing for sex-sorted semen than the onset of estrus.     

日粮中添加蛋氨酸锌对奶牛生产性能和相关生化指标的影响

选择12头中国荷斯坦奶牛随机分为4组,采用4×4拉丁方试验设计,A组为对照组(基础日粮),B、C和D组分别在A组基础上添加120、280和380 mg/kg蛋氨酸锌,研究其对奶牛生产性能和相关生化指标的影响。结果表明:B、C和D组的日均泌乳量分别比A组提高了1.28kg(5.65%)、1.59 kg(7.02%)和1.66 kg(7.33%),均差异显著(P<0.05);4%标准乳量分别提高了0.98 kg(4.73%)、1.22 kg(5.89%)和1.16 kg(5.60%),均达差异显著水平(P<0.05);乳脂率、乳糖、非脂乳固形物含量均差异不显著(P>0.05);乳蛋白分别提高了4.56%、7.02%和7.72%,均差异显著(P<0.05);乳锌含量分别提高了1.05μg/mL(36.59%)、1.59μg/mL(55.40%)和2.08μg/mL(72.47%),均差异极显著(P<0.01);体细胞数分别降低了1.64×104/mL(5.65%)、3.23×104/mL(11.12%)和3.89×104/mL(13.39%),均差异显著(P<0.05);平均干物质采食量分别提高了0.19 kg(0.98%)、0.29 kg(1.51%)和0.32 kg(1.66%),均差异不显著(P>0.05)。经济效益分析表明,C组每牛日均比A组增收3.42元,最为理想。     

棉子糖对草鱼生长性能和血清生化指标的影响

为了研究棉子糖对草鱼生长和血清生化指标的影响,选取初均重(69.51±6.29)g的草鱼288尾,随机分为6组,每组3个重复,每个重复16尾鱼.对照组饲喂基础饲料,试验组分别饲喂含200、400、800、1200和2000 mg/kg棉子糖的试验饲料,试验期为70 d.结果显示:与对照组相比,1)添加棉子糖能够提高草鱼的特定生长率,降低饲料系数,其中1200 mg/kg组与其余各组差异显著(P<0.05);2)各试验组蛋白质沉积率均有所提高,但无显著差异(P>0.05);脂肪沉积率除400 mg/kg组外,其余各试验组均显著升高(P<0.05);尤以1200 mg/kg组的蛋白质沉积率和脂肪沉积率最高;3)各试验组血清甘油三酯含量显著升高(P<0.05),高密度脂蛋白、低密度脂蛋白含量均显著降低(P<0.05).由此得出:1)棉子糖能够提高草鱼对饲料的吸收利用,增强鱼体对脂肪的吸收并节约蛋白质,从而促进草鱼生长;2)棉子糖可以明显的起到调节草鱼脂质代谢的作用.     

金属硫蛋白对热应激奶牛血淋巴细胞凋亡基因和HSP70基因表达的影响

为探讨金属硫蛋白(MT)对热应激奶牛血淋巴细胞凋亡基因和HSP70基因表达的影响及其机理,选取25头中国荷斯坦奶牛经产泌乳母牛,随机均分为A、B、C、D、E 5组,分别按每头0(对照),16.0,24.0,32.0和40.0 mg颈静脉注射Zn-MT,于试验第1(注射Zn-MT之前),7和14天逐头采取血样,测定不同剂量的外源性MT对热应激奶牛血淋巴细胞HSP70、Bcl-2、Bax和p53基因表达水平的影响。结果表明,补给外源性MT后,4个试验组奶牛的产奶性能都有不同程度提高,其中B组奶牛的产奶量比A、C、D和E组分别高出20.94%(P＜0.05),15.83%(P＞0.05),10.94%(P＞0.05)和8.85%(P＞0.05);各试验组HSP70基因的表达水平都有所上升,其中D组比对照组高出130.00%,达到显著(P＜0.05)水平;各试验组Bcl-2基因的表达水平均高于对照组,其中C组达到显著(P＜0.05)水平;B、D组Bax基因的表达水平和C、E组p53基因的表达水平较对照组分别降低了22.00%,13.00%和22.00%,34.00%,但均未达到显著(P＞0.05)水平。说明外源性MT能改善热应激奶牛的产奶性能并有效调控奶牛血淋巴细胞HSP70、Bcl-2、Bax和p53基因的表达水平,且表现出较为明显的剂量效应。     

饲料铜水平对生长猪血清铜、血清锌和血清铁的影响

选 60头生长白猪 ( 1 9.2 6± 1 .2 0 kg)随机分成 6组 ,每组公母各半 ,使用硫酸铜作为铜源 ,在饲料中添加不同浓度的铜 ,对照组铜添加浓度为 0 mg/kg,高铜试验各组添加浓度为 1 0 0、1 5 0、2 0 0、2 5 0和 30 0 mg/kg。试验期为 80 d,期间每隔 2 0 d采血一次 ,检测血清铜、血清铁和血清锌的含量。分析结果显示 :高铜饲料可明显提高血清铜含量 ,降低血清锌含量 ,但血清铁无显著性变化。第 2 0 d高铜各组平均血清铜比对照组提高 1 7.7% ( P<0 .0 5 ) ,第 40 d提高 2 0 .2 % ( P<0 .0 5 ) ,第 60 d提高 8.6% ( P>0 .0 5 ) ,第 80 d提高 31 .5 % ( P<0 .0 1 ) ,30 0 mg/kg高铜组与对照组比较差异显著 ( P<0 .0 5 )。血清锌第 2 0 d和 40 d,高铜各组平均比对照组降低 1 1 .6%和 1 0 .3%。