Determination of plasma vitamin C concentration in fattening cattle

Plasma vitamin C (ascorbic acid + dehydroascorbic acid) concentration is a good index of the nutritional status of vitamin C. However, the methodologies for storage and analyses have not been investigated in bovine plasma. The validity of an analytical method for bovine plasma using high performance liquid chromatography (HPLC) with a spectrophotometric detector was examined. Exogenous dehydroascorbic acid was almost completely converted to ascorbic acid during the preparation for analysis with a reducing reagent, dithioerythritol. The analytical recoveries of ascorbic acid were high. Ascorbic acid was not detected after treatment with ascorbic acid oxidase. Thus, the specificity of this method is considered to be high. Although vitamin C was stable in plasma treated by dithioerythritol at ?20°C for 6 days, vitamin C in untreated plasma significantly decreased during 3‐day storage at ?20°C. These results indicate that the HPLC method is suitable for the determination of plasma vitamin C in cattle and that the storage conditions are important for determination of plasma vitamin C. Plasma vitamin C concentration ranged between 1.49 mg/L and 3.33 mg/L in fattening cattle. This result suggests that fattening cattle show large individual variation in plasma vitamin C concentration.     

Change of clopyralid concentration in recycled beef cattle compost

Composting of beef cattle manure using sawdust or recycled compost as a bulking agent was investigated for the management of clopyralid risk, such as changes in the clopyralid concentration and the mechanism of clopyralid accumulation caused by recycled compost. These raw materials were composted with laboratory equipment, which was controlled at 60℃ after the temperature peak by autothermal composting. Clopyralid concentration did not changed during composting in the thermophilic phase; on the contrary, it increased because clopyralid accumulated in compost when recycled compost was used repeatedly as a bulking agent. The clopyralid accumulation ratio (ratio of clopyralid concentration to that in the first compost) could be explained by a model using a recurrence formula, and a correlation existed between the calculated (model) accumulation ratios and measured accumulation ratios (R² = 0.78). Using this model, the excessive accumulation of clopyralid could be controlled when using recycled compost as a bulking agent with lower moisture content or when part of the recycled compost was replaced by another bulking agent, even if recycled compost had high moisture content. In future work, the model and its considerations should be verified in a field test.     

Eliminating the effect of epidural fat during dorsolumbar epidural analgesia in cattle

Objective To compare the distribution of new methylene blue (NMB) solution injected into either the subperiosteal space or under the epidural fat at the first and second lumbar vertebral interspace in cattle. Study design Prospective experimental study. Sample population Nine nonpregnant cows. Methods Needles were advanced towards the first interlumbar epidural space using a dorsal mid‐line approach. Upon confirmation of successful penetration of the ligamentum flavum, group 1 received 5 mL of 0.12% NMB in 0.9% saline. In group 2, the needle was slowly advanced a further 7–10 mm to ensure injection under the epidural fat; the same dose was injected. The extent of cranial and caudal migration of dye, as indicated by staining of epidural fat and the dura mater was measured. Results In group 1 (n = 4), NMB solution migrated only between the periosteum and the epidural fat. There was unilateral distribution in two cows. In contrast, there was no difference between left‐ and right‐sided distribution in group 2 (n = 5), and the NMB solution migrated only between epidural fat and the dura mater. Although the dura mater was not penetrated in any animal of group 2, the dorsal roots were slightly stained and the overlying dura mater was heavily stained in these animals. Conclusions and clinical relevance Variation in distribution of local anaesthetic solution can probably be overcome by deeper needle penetration of the epidural fat.     

肉牛人工冻配受胎率试验研究

[目的]为提高人工冻配受胎率,降低肉牛饲养成本,提高肉牛养殖经济效益。[方法]通过对冻配不同部位、不同时间及解冻温度等进行统计分析。[结果]结果表明,在发情结束后4～6 h,输精部位在子宫角1/3处,解冻温度为40℃输精,母牛的受胎率为最高。     

Differences in the behavior of the crossbred steers of different sire lines of Japanese Black cattle

We determined differences in the behavior of the progeny of two major sire lines of Japanese Black cattle by recording the behavior of 35 and 70 half-sib steers of sires from fast (FG) and slow (SG) growing lines, respectively. Two sire lines of steers were mixed and allocated to nine pens with 11–12 animals per pen. The proportion of steers lying was significantly (P < 0.001) higher in the SG line (43.4 ± 5.7% compared to 40.3 ± 6.0%). The proportion of time spent eating concentrate feed (FG: 12.1 ± 2.3%; SG: 11.4 ± 2.1%), drinking (FG: 0.8 ± 1.1%; SG: 0.4 ± 0.6%), licking the feed trough (FG: 0.4 ± 0.6%; SG: 0.2 ± 0.4%) and performing tongue-playing (FG: 3.1 ± 4.6%; SG: 1.0 ± 1.9%) was significantly higher in FG, whereas the proportion of time spent resting (FG: 41.5 ± 12.8%; SG: 43.7 ± 10.9%) and performing self-licking (FG: 1.7 ± 1.4%; SG: 2.1 ± 1.3%) was higher in SG (all P < 0.05). These results show progeny of the FG sire engaged in more active behaviors compared to the progeny of the SG sire line.     

湛江地区肉牛棚舍环境评价

为了解热带地区双坡式棚舍散栏饲养模式下的环境特征,在湛江测定了肉牛舍的温度、湿度、气流、PM10等指标。结果表明:棚舍内外温湿度几乎相同,换气量超过了最大换气量,PM10优于卫生标准,温湿指数范围为78～85,处于热应激状态。考虑了气流影响的体感温度范围为25～30.5℃,晴天的14:00和19:00,风速为0.95～1.30 m/s,气流显著地减少了高温的影响。棚顶隔热能力差,晴天棚顶内外表面温差不足1℃,棚顶内表面最高可达60.8℃,此时的舍内气温仅为33.4℃,棚舍自然换气调节是环境控制的主体。     

慎防牛呼吸系统疾病综合征吞利毁场

牛呼吸系统疾病综合征(BRDC)是由病原体感染、应激刺激和机体抵抗力下降等病因共同作用引起牛的一种以发热、神差纳少和鼻炎、气管炎、支气管炎、肺炎为主要临床表现的一类传染性疾病的总称,又被称为“运输热。本病多在秋冬季或春夏之交呈地方性或散发性流行,常以多种病原体相互协同作用的感染、复杂的病情导致犊牛(特别是45日龄内的犊牛)和新引进牛相当高的发病率和大批量的死亡而侵吞养牛的利润甚至推毁养牛场,是一个严重困扰养牛业的世界性问题。作者综述了BRDC的危害、病因、快速诊断,并从养牛生产实际出发较为详细地阐述了BRDC的预防与治疗技术措施,对防控BRDC有一定的实际指导意义。     

育肥肉牛屠宰率与活体、胴体价格之间的关系分析

为探讨育肥牛屠宰率与活体、胴体价格之间存在的关系,为促进肉牛屠宰加工企业按质论价提供参考。本文从屠宰场收购育肥牛的日常价格入手,利用3个时间段的具体事例,通过假设类推法开展分析研究。结果表明,活胴价比等于盈亏平衡点屠宰率,盈亏平衡点屠宰率与胴体价格呈反向变化规律。在现实交易中,与活胴价比相等的那个屠宰率的点上出售活体牛与胴体收益相等,但是胴体价格会有相应的变化,双方相互兼顾,争取利益最大化。     

肉牛同期发情效果影响因素的研究

[目的]为了研究同期发情处理方法、繁殖状况、品种、体重等对肉牛同期发情效果的影响,[方法]选择140头不同繁殖状况、品种、体重的肉牛,随机分为3组,分别采用CIDR+第10天肌注PMSG+第11天肌注PGF_2α（埋栓Ⅰ组）、CIDR+第9天肌注PMSG+第11天肌注PGF_2α（埋栓Ⅱ组）、肌注PGF_2α+PMSG(PGF_2α组)的方法进行同期发情处理。[结果]3种不同处理方法相比,PGF_2α组发情率为87.10%,埋栓Ⅰ组、Ⅱ组母牛发情率分别为97.83%、98.41%,显著高于PGF_2α组（P<0.05）;PGF_2α组处理牛受胎率为83.87%,埋栓Ⅰ组、Ⅱ组处理牛受胎率分别为89.13%、84.13%,高于PGF_2α组,但差异不显著（P>0.05）;育成牛与经产牛发情时间相比,埋栓组12～24 h内出现发情症状的经产牛占比为27.27%,育成牛占比为60%,显著高于经产牛（P<0.05）,2...     

湟源县黄牛血钾浓度的测定

采用火焰光度计法测定了湟源县日月乡黄牛４０份血样的血钾浓度。测定结果为：全血钾浓度９．１６ｍｍｏｌ／Ｌ；红细胞钾浓度１９．７９ｍｍｏｌ／Ｌ；血清钾浓度４．３５ｍｍｏｌ／Ｌ。全血钾浓度和红细胞钾浓度呈显著的正相关关系（ｒ＝０．９４４１Ｐ＜０．００１）     

营养水平对杂交肉牛FABP3基因表达及IMF的影响

为研究营养水平对杂交肉牛心脏型脂肪酸结合蛋白（FABP3）基因表达及肌内脂肪含量（IMF）的影响,以西门塔尔、利木赞和夏洛莱杂交肉牛为研究对象,利用实时荧光定量PCR技术,分别测定高、中、低营养水平的3种杂交肉牛背部脂肪中FABP3mRNA表达水平,并测定其背最长肌IMF。结果：（1）高营养组中夏洛莱牛IMF高于同营养组其他2种肉牛,其背部脂肪中FABP3mRNA水平也显著高于另外2种杂交肉牛（P〈0.01）;中营养组中西门塔尔和利木赞牛IMF均高于同营养组的夏洛莱牛,但FABP3mRNA的水平无显著差异（P〉0.05）;低营养组中夏洛莱牛IMF和FABP3mRNA水平均显著低于另外2种肉牛（P〈0.01）;（2）夏洛莱杂交肉牛背部脂肪中FABP3mRNA水平与IMF具有显著的相关性（P〈0.05）,而西门塔尔和利木赞牛中FABP3mRNA水平与IMF无显著相关性（P〉0.05）。该结果表明提高营养水平影响FABP3mRNA表达并在一定程度上影响IMF,但影响显著与否存在品种差异,在肉牛育种和牛肉生产中应当同时考虑营养因素和遗传因素。     

Dietary conjugated linoleic acids increase intramuscular fat deposition and decrease subcutaneous fat deposition in Yellow Breed × Simmental cattle

This study was conducted to estimate the effect of dietary conjugated linoleic acids (CLA) on intramuscular and subcutaneous fat deposition in Yellow Breed × Simmental cattle. The experiment was conducted for 60 days. The results showed that the average backfat thickness, (testicles + kidney + pelvic) fat percentage and subcutaneous fat percentage in dietary CLA were significantly lower than in the control group, while intramuscular the fat percentage was significantly higher. Compared to the control group, the Longissimus muscle enzyme activities of lipoprotein lipase (LPL), fatty acid synthase (FAS) and acetyl‐coenzyme A carboxylase (ACC) in dietary CLA and the subcutaneous fat enzyme activities of LPL, hormone‐sensitive lipase (HSL) and carnitine palmitoyltransferase‐1 (CPT‐1) were significantly increased. Similarly, compared to the control group, the Longissimus muscle sterol regulatory element binding protein 1 (SREBP‐1), FAS, stearoyl‐coenzyme A desaturase (SCD), ACC, peroxisome proliferator‐activated receptor γ (PPARγ), heart fatty‐acid binding protein (H‐FABP) and LPL gene expression in dietary CLA were significant increased, as were the subcutaneous fat of PPARγ, H‐FABP, LPL, CPT‐1 and HSL in dietary CLA. These results indicated that dietary CLA increases IMF deposition mainly by the up‐regulation of lipogenic gene expression, while decreasing subcutaneous fat deposition mainly by the up‐regulation of lipolytic gene expression.     

A comparison of an enzymatic and a gas-chromatographic method for measuring the acetate concentration in the blood plasma of cattle

The concentration of acetate in blood plasma was measured by both a gas-liquid chromatographic method and an enzymatic method using acetyl-CoA synthetase. When acetate was measured enzymatically without previous protein precipitation, the apparent concentration was lower than when the concentration measured by either a gas-chromatographic method or by the enzymatic method after protein precipitation with perchloric acid and neutralization.     

Determination of serum ionized calcium concentration in dairy cattle after frozen anaerobic storage

The stability of serum ionized calcium concentration (ICa) from dairy cows was studied after anaerobic collection and frozen storage. Paired blood samples were obtained from five groups of cows: nonlactating, first third of lactation, midlactation, last third of lactation, and 2-year-old nonlactating heifers. Vacutainer multiple sample needles and serum separator tubes (SST) were used for venipuncture. Aspiration of serum was within 1.5 hours after collection: one sample for immediate determination (within 2 hours of collection); the other sample stored at -4 degrees C in evacuated plastic vacutainer tubes filled with serum to provide dead space of less than 75% of volume, and analyzed after 14 to 30 days in storage (half, 15, of the samples from each lactation group were analyzed after frozen anaerobic storage at 14 or 30 days, respectively). Processing samples in this manner significantly altered the values obtained for ICa, normalized calcium concentration (NCa), and pH. Analysis after frozen storage in evacuated tubes caused ICa and NCa concentrations to decrease and pH to increase (P< 0.05); total calcium levels were not significantly different from initial values. There were no significant differences among lactation groups. The difference between values obtained from these paired samples was either due to loss of CO(2) during transfer from the SST to the evacuated tube or during frozen storage. Changes in samples assayed after freezing and storage could be adjusted to original values by using the mean difference between the fresh and frozen levels as correction factors: ICa (+0.4379), NCa (+0.2797), and pH (-0.0926). It was concluded that immediate determination of serum ICa in dairy cattle is the ideal but using this methodology and performing analyses later may be acceptable if correction factors are determined.     

乳牛衣原体病灭活疫苗的研制

将免疫原性稳定的鹦鹉热衣原体SX5菌株灭活，加入油佐剂制备乳牛衣原体病灭活疫苗，并对疫苗的安全性进行了检测。用该疫苗对成年牛和犊牛进行了最小免疫量试验、效力试验和免疫持续期试验；结果表明，最小免疫量分别为3mL和5mL，平均免疫保护率达94．4％。免疫持续期达10个月。疫苗保存期试验表明，在4℃条件下可保存12个月。本动物安全试验和田间小试免疫证明，该疫苗安全性好，乳牛注射疫苗后饮食、产乳量及注苗部位没有明显的异常变化。     

夏季皖东牛与荷斯坦牛皮肤汗腺及其散热调节特征

为了探究夏季高温时皖东牛与荷斯坦牛皮肤组织形态和皮肤散热调节特征的差异,在30℃以上的夏日,选择皖东牛和荷斯坦牛母牛各4头,屠宰后采集颈部、肩部、背部、腹部、臀部和腿部6个部位的皮肤样本,通过HE染色切片分析皮肤的汗腺(SWG)与皮脂腺(SEG)的分布与形态,测定皮肤组织乙酰胆碱(ACh)浓度及乙酰胆碱转移酶(AChT)和酯酶(AChE)活力,采用RT-qPCR和Western blot检测皮肤组织乙酰胆碱M3受体(ACh M3R)、一氧化氮合酶(eNOs)及水通道蛋白5(AQP5)mRNA和蛋白的表达。结果:部位间比较,皖东牛与荷斯坦牛表皮厚度均为背部最厚,颈部最薄(P<0.05)。品种间比较,皖东牛平均皮肤厚度较高,平均表皮厚度较薄(P<0.05);汗腺密度与皮脂腺密度品种间无显著差异(P>0.05);皖东牛汗腺和皮脂腺的平均长度、直径、深度、体积均显著增加(P<0.05)。肩部、背部和臀部皮肤对比:夏季皖东牛和荷斯坦牛皮肤组织ACh浓度品种间无显著差异(P>0.05),部位间以臀部最高,肩部次之,背部最低(P<0.05)。ACh M3R和AQP...     

人绒毛膜促性腺激素对母牛受胎率的影响

几年来,广西象州县的多个牛人工授精品改点的受胎率,黄牛为40%~50%,水牛为30%~40%,在这样的情况下,牛的受胎率有待提高。人绒毛膜促性腺激素在母牛体内具有促进卵泡发育、排卵的作用;利用人绒毛膜促性腺激素的这一特性,在母牛发情时肌肉注射,然后进行输精,观察对母牛的受胎率的影响,是否能够提高牛人工授精工作的效益。结果显示,在牛人工授精工作中使用了人绒毛膜促性腺激素,能够提高受胎率,也提高了工作效益。     

Relationship between leptin content, metabolic hormones and fat deposition in three beef cattle breeds

The aim of the study was to determine if cattle breeds differing in their carcass characteristics also differ in the profiles of their leptin and metabolic hormones. Three breeds, Belgian Blue (BB) (n = 12), Limousin (L) (n = 12) and Aberdeen Angus (AA) (n = 12) with varying ability to deposit fat and protein were compared. Blood, muscle and subcutaneous (SC) adipose tissue were sampled. Animal performance, carcass and meat characteristics were determined as well as plasma leptin concentration, leptin gene expression in SC adipose tissue, leptin-receptor gene expression in SC adipose tissue and plasma concentration of insulin, tri-iodothyronin (T3), thyroxin (T4) and cortisol. The BB bulls showed the lowest values of leptin gene expression (P < 0.05). Values of plasma leptin concentration and of leptin-receptor gene expression tended to be lower in BB than in the other breeds. For a similar amount of adipose tissue (after normalisation), BB bulls showed a higher ratio of plasma leptin (P < 0.05), whereas normalised leptin gene and leptin-receptor gene expressions did not significantly differ between breeds. Belgian Blue bulls also differed in their metabolic hormone profile, tending to show lower values of insulin, T3 and T4 than the two other breeds. Cortisol levels were significantly lower (P < 0.05) in BB than in L and AA animals.     

柠檬酸稀土对锦江黄牛屠宰性能、肉品质及脂肪代谢的影响

本试验旨在研究柠檬酸稀土对锦江黄牛屠宰性能、肉品质及脂肪代谢的影响。选用年龄、体质量相近的健康育肥期锦江公牛为试验动物,共12头,平均体质量为(374.75±4.02)kg,随机分成2组,即对照组和试验组,在试验组饲粮中的添加柠檬酸稀土400 mg/kg,对照组不添加柠檬酸稀土。试验期为期70 d。饲养试验结束进行屠宰,测定其屠宰性能,分析测定肉品质指标和脂肪代谢相关酶及激素指标。结果显示:饲粮中添加柠檬酸稀土显著提高了平均日增质量(P<0.05),显著降低了料质量比(P<0.05);饲粮中添加柠檬酸稀土可显著提高血清中GH和瘦素的水平(P<0.05);饲粮中添加柠檬酸稀土显著降低了育肥期锦江黄牛的脏脂率和脂肪率(P<0.05),有降低背膘厚及板油率的趋势(0.05≤P≤0.1);饲粮中添加柠檬酸稀土显著提高了牛肉中粗蛋白的含量(P<0.05),降低了粗脂肪及干物质的含量(P<0.05),同时具有提高剪切力的趋势(0.05≤P≤0.1);饲粮中添加柠檬酸稀土显著降低了肝脏中MDA的活性(P<0.05),对FAS活性具有降低的趋势(0.05≤P≤0.1);饲粮中添加柠檬酸稀土显著提高了肝脏中LPL的活性(P<0.05),对TL也有升高的趋势(0.05≤P≤0.1)。结果表明,饲粮中添加400 mg/kg的柠檬酸稀土可改善锦江黄牛生产性能和屠宰性能,提高肌肉中粗蛋白含量,同时还有明显的降低育肥期锦江黄牛体内脂肪含量的作用,提高肉牛养殖效益。