Effect of level of milk replacer fed to Holstein calves on performance during the preweaning period and starter digestibility at weaning

Calves following an enhanced-growth feeding program usually show lower starter intakes during the preweaning period compared with conventionally-fed calves. To assess whether this low intake in calves following an enhanced-growth feeding program affects calf capacity to digest starter after weaning, 19 Holstein male calves were used to measure apparent nutrient digestibility at weaning. Calves were divided in two groups: calves on a conventional feeding program (CF) and calves on an enhanced-growth feeding program (EF). After one week of adaptation to milk replacer (25% CP and 19% fat), the CF calves were fed 4 l/d of milk replacer (MR) at 12.5% DM dilution rate from d 1–28, and 2 l/d from d 29 to weaning day at d 35, and the EF calves were offered MR at 18% DM dilution rate: 4 l/d from d 1–6, 6 l/d from d 7–13, 7 l/d from d 14–20, 6 l/d from d 21–28, and 3 l/d from d 29 to 35. Calf starter (20% CP) was offered ad libitum from the beginning to the end of study at d 42, and its consumption was recorded daily. Calves were weighed at d 3, 17, 24, 31, 38 and 42. Daily total faeces collection was conducted for the last 5 d of study. Final BW was numerically greater in EF than in CF calves (88.6 vs 81.2 ± 3.36 kg, respectively). Starter DMI was greater (P < 0.05) in CF compared with EF calves during the preweaning (0.68 vs 0.36 ± 0.078 kg/d, respectively) and postweaning (2.52 vs 1.90 ± 0.102 kg/d, respectively) periods, but there were no differences in total DMI (1.12 and 1.26 ± 0.078 kg/d, in CF and EF calves, respectively) during the preweaning period. However, apparent DM, OM, NDF, CP, and GE digestibility coefficients were greater (P < 0.05) in CF compared with EF calves (77.4 vs 71.8 ± 1.23%, 78.7 vs 73.2 ± 1.18%, 34.7 vs 20.3 ± 3.79%, 77.1 vs 71.6 ± 1.29%, and 75.6 vs 69.8 ± 1.25%, respectively) the week after weaning. It is concluded that calves in the EF treatment presented lower nutrient digestibility coefficients compared with CF calves the week after weaning.     

犊牛腹泻与肠道菌群的变化

本文检测腹泻犊牛的直肠内8种主要正常菌群的变化,并与健康犊牛进行对比。结果发现,犊牛腹泻时,大肠杆菌、双岐杆菌和乳杆菌变化较大,而其它菌群变化较小。腹泻或将腹泻时,大肠杆菌数增加,双岐杆菌和乳杆菌数下降。腹泻康复或即将康复时,大肠杆菌减少,双岐杆菌、乳杆菌数增加。     

犊牛类圆线虫病调查

笔者１９８５～１９９３年对犊牛类圆线虫病作流行病调查,１８５０头水牛犊类圆线虫虫卵阳性率１８％,１７５头腹泻水牛犊阳性率１３．８％,１～１０日龄均为阴性,１１～９０日龄阳性率２３％,９１～１６１日龄阳性率１７％,１６１～３６０日供阳性率１４．６％;１～３月份阳性率１７％,４～８月份阳性率２０．５％,９～１２月份阳性率１２％。     

我国发生Leachii支原体引起的犊牛多发性关节炎

2009年2月～6月我国某奶牛场发生严重的犊牛多发性关节炎,发病犊牛的症状与最早发生于澳大利亚的犊牛Leachii支原体关节炎非常相似。为确定病原,我们无菌采集2份具有典型症状犊牛的关节液样品进行实验室诊断,2份样品中均检测和分离出支原体。将2个分离菌株的16S rRNA基因和LppA基因与参考支原体菌株进行核苷酸序列比对,发现这2株支原体的16S rRNA基因和LppA基因均与Leachii支原体具有最高的核苷酸序列同源性,分别为99.9%和99.6%。结果显示,本研究分离的2株支原体为Leachii支原体,分别命名为GN407和GN408。综合分析发病犊牛的临床病理学观察和关节液样品的实验室诊断结果,我们确定Leachii支原体为该奶牛场犊牛多发性关节炎的病因。     

犊牛常见病的诊治体会

犊牛的健康关系着牛场的未来生产.本文介绍了几种犊牛常见病的辨别及诊断方法,帮助牛场快速进行疾病判断.作者对几种疾病的病因、临床症状、诊断方式、治疗方法进行综述,旨在为犊牛的常见病的防控和选择治疗药物提供参考依据.     

Pharmacokinetic study of an injectable long-acting parenteral formulation of doxycycline hyclate in calves

Doxycycline hyclate (DOX-h) can be regarded as a time-dependant antibacterial. Hence, a parenteral long-acting formulation may be regarded as more pharmacologically sound. A poloxamer-based matrix was used to produce a long-acting injectable preparation (DOX-h-LA) and its serum concentrations vs. time profile investigated after its s.c. injection to calves. Serum concentrations profiles for such a prepartion were compared to the corresponding profiles obtained with an aqueous formulation of DOX-h injected either i.m. or i.v. in 10 calves in a crossover study at dose of 10mg/kg, with washout periods. DOX-h-LA showed the greatest values for bioavailability (602%); maximum serum concentration (C(max)) value was 1.99microg/mL with a time to reach C(max) (T(max)) of 25h and an elimination half-life of 40.81h. Considering minimum effective serum concentration of 0.5microg/mL a dose-interval of 80h can be achieved for DOX-h-LA, and only 9.7h and 17h after the i.v. or i.m. administration of DOX-h, respectively.     

大豆黄酮对犊牛生长性能及免疫机能的影响

研究大豆黄酮对犊牛生长发育及免疫机能的影响。方法是选取16头犊牛随机分为两组,分别于鲜奶中添加0g／（d·头）、2．5g／（d·头）大豆黄酮。试验前后采血,采用ELISA分析血浆q-T3、T4、IgG、IgA等指标。试验结果表明,大豆黄酮能明显提高血浆中的T3、T4、IgG、IgA水平。结果显示大豆黄酮可能参与了犊牛的免疫调节过程,可提高犊牛的体液免疫水平。     

犊牛代乳品M868饲喂效果报告

通过犊牛代乳品饲喂试验结果证明犊牛代乳品具有较高的营养价值可完全代替母乳同时其可以提高犊牛的精粗料采食量试验组犊牛比对照组平均日增重高17g节约饲养成本224元因此犊牛代乳品的应用具有较高的经济效益和推广前景。     

Dynamics of viral spread in bluetongue virus infected calves

The kinetics of viremia and sites of viral replication in bluetongue virus (BTV) infected calves were characterized by virus isolation, serology and immunofluorescence staining procedures. In addition, the role of the regional lymph node and lymphatics draining inoculated skin in the pathogenesis of BTV infection was determined by analyzing efferent lymph collected from indwelling cannulas. Viremia persisted for 35 to 42 days after inoculation (DAI) and virus co-circulated with neutralizing antibodies for 23 to 26 days. Virus was first isolated from peripheral blood mononuclear (PBM) cells at 3 DAI, after stimulation of PBM cells with interleukin 2 and mitogen. BTV was frequently isolated from erythrocytes, platelets and stimulated PBM cells but never from granulocytes and rarely from plasma during viremia. Virus was consistently isolated from erythrocytes late in the course of veremia. Interruption of efferent lymph flow by cannulation delayed the onset of viremia to 7 DAI. BTV was infrequently isolated from lymph cells, and few fluorescence positive cells were observed after lymph and PBM cells were labelled with a BTV-specific monoclonal antibody. Virus was isolated from spleen by 4 DAI and most tissues by 6 DAI, whereas virus was isolated from bone marrow only at 10 DAI. Virus was not isolated from any tissue after termination of viremia. It is concluded that primary viral replication occurred in the local lymph node and BTV then was transported in low titer to secondary sites of replication via infected lymph and PBM cells. We speculate that virus replication in spleen resulted in release of virus into the circulation and non-selective infection of blood cells which disseminated BTV to other tissues. Virus association with erythrocytes likely was responsible for prolonged viremia, although infected erythrocytes eventually were cleared from the circulation and persistent BTV infection of calves did not occur.     

The labour input associated with calf care on Irish dairy farms

The objective of this study was to quantify the overall labour requirement for calf care and how it is influenced by enterprise scale and facilities, together with an evaluation of specific calf-feeding systems with respect to labour requirement and calf performance. One hundred and twenty nine spring-calving dairy herds participated in the investigation of overall labour input. Herds were categorized into three groups depending on herd size (small = < 50 cows, medium = 50 to 80 cows, large = > 80 cows). The total average time consumed by calf care per farm increased (P < 0.01) with herd size and the average time consumed per calf was highest in the small herd group (2.1 min/day). The proportion of farms bucket feeding was lower (P < 0.05) and the proportion feeding calves ad libitum and using cold milk was higher (P < 0.05) with the large group compared to the small herd group. Fifty-seven of the 129 herds participated in the measurement of labour input associated with specific calf-feeding systems. The labour input time per calf required for the task of milk feeding tended (P = 0.08) to be longer when calves were fed twice daily, using buckets or teats compared to automatic feeders, once daily feeding with teats and twice daily feeding with a trough. The labour input per calf for the cleaning of milk feeding equipment and for bedding and cleaning calf pens was greater (P < 0.05) with automatic feeding systems compared to the other feeding systems. A further sub-set of ten herds (from the 57 herds) underwent calf performance measurements. The mean calf weight at day 77 for automatic feeding, once daily feeding, twice daily feeding with teats and twice daily feeding with troughs was 95, 95, 93, 91 kg, respectively. In conclusion, labour input associated with calf care was influenced by herd size (and indirectly calf number), and calf-feeding system. Milk feeding of calves on a once daily basis tended to reduce the total labour input per calf and did not adversely affect calf performance. Thus, it is possible to improve efficiency of calf care by selecting time efficient methods of calf-feeding without affecting calf performance.     

早期补饲对规模养殖条件下平凉红牛犊牛体重的影响

[目的]为了探索早期补饲对规模养殖条件下平凉红牛犊牛体重发育的影响,[方法]选取分娩日期接近的妊娠母牛18头,分为试验组和对照组,早期补饲试验组犊牛,分析各月龄体重数据。[结果]结果表明在规模化养殖条件下,与传统养殖方式相比,对平凉红牛犊牛采取早期补饲,犊牛在3月龄到6月龄时体重差异显著（P<0.05）。[结论]因此,在实际生产中应重视犊牛早期的隔栏补饲工作,有利于提高肥牛生产效率和经济效益。     

不同喂奶方案对犊牛生长发育及健康状况的影响

为了揭示犊牛的生长发育规律,为犊牛生长制定良好的喂奶方案,本研究以27头荷斯坦公犊为研究对象,根据日龄和日喂奶量,采用三种喂奶方式,收集测定生长性能指标及健康指标。结果表明:不同喂奶方案对犊牛开食料采食量、100日龄料重比、体尺指数(体高、体斜长、胸围、管围)、器官指数(心脏、肝脏、脾脏、肾脏、肺脏)均无显著影响(P>0.05)。饲喂二组能够显著提高100日龄犊牛平均日增重,并有效降低腹泻率(P<0.05);就经济效益而言,相比对照组,饲喂二组每增加1 kg犊牛体重平均成本低0.61元,远高于饲喂一组(成本降低0.08元)(P<0.05)。综上所述,不同喂奶方案影响犊牛的生长性能和牧场成本效益,本试验中Group C应用效果最佳。     

犊牛阿维菌素中毒的组织病理学观察

本试验应用常规石蜡切片技术,H.E染色镜检观察阿维菌素中毒犊牛的心脏、肝脏、脾脏、肺脏、肾脏、肠系膜淋巴结、空肠、瘤胃8个组织器官,结果表明:各脏器主要病理变化是出血和瘀血;心肌纤维断裂、变性坏死,间质内充满大量炎性细胞;肝脏实质细胞肿胀,脂肪变性,叶间静脉内出现均质红染浆液;肺泡内有浆液渗出;肾小管凝固性坏死,肾小球肿胀,间质内出现水肿液;淋巴结淋巴中心细胞坏死。这些器管组织的损伤变化,有助于进一步探索阿维菌素中毒的发病机制及病理特征,从而为及时对发病动物进行确诊治疗提供形态学依据。     

Anti-Neospora caninum antibody detection and vertical transmission rate in pregnant zebu beef cows (Bos indicus): Neospora caninum in pregnant beef cows (Bos indicus)

The aim of the present study was to evaluate anti-Neospora caninum antibodies and the vertical transmission rate in naturally infected pregnant zebu beef cows (Bos indicus) reared on pasture. The present study began with 200 cows from four farms (50 cows from each farm), and these animals were submitted to timed artificial insemination (TAI). After ultrasonography, 76 pregnant cows were selected, 22, 15, 22, and 17, respectively, from farms 1, 2, 3, and 4. Blood samples were taken from cows thrice during the first, second, and third trimester of gestation, and a blood sample was collected from 31 calves before colostrum milking. From 76 cows 23 (30.3%) had anti-N. caninum antibodies detected by indirect ELISA (Idexx), and 53 (69.7%) did not. Sixty-four cows that initiated the experiment were negative to N. caninum and 11 became positive either during the second or third trimester of gestation, this mean an infection incidence of 17.2% (11/64). OD for ELISA was higher (OD = 2.08) during the second and third (OD = 2.10) trimesters of pregnancy when compared with the first (OD = 1.81), however, there were no statistical differences (P = 0.45). The vertical transmission was calculated to be 29.0% (9/31), and the risk of vertical transmission of N. caninum in seropositive dams was 26.25 times higher than seronegative animals (OR = 26.25, 2.38 < OR < 289, P = 0.007). In conclusion, the rate of vertical transmission of N. caninum in pregnant zebu beef cows was 29%, and the risk was 26.25 higher in seropositive dams relative to than seronegative animals.     

Clinical assessment of epidural analgesia induced by xylazine-lidocaine combination accompanied by xylazine sedation in calves

: The aim of the present study was to investigate whether epidural administration of a xylazine-lidocaine combination accompanied by xylazine sedation would provide satisfactory analgesia for some surgical procedures on 10 calves admitted to the Department of Veterinary Surgery, University of Kafkas with perineal urolithiasis (n:2), rectovaginal fistula (n:1), atresia ani (n:2), omphalophlebitis (n:2), omphaloarteritis (n:1) and umbilical hernia (n:2).Following intramuscular injection of xylazine at a dose of 0.05 mg/kg for sedation, xylazine-lidocaine combination (0.2 mg/kg lidocaine + 0.02 mg/kg xylazine + 5 ml 0.9% NaCl) was administrated into the lumbosacral (L6-S1), sacrococcygeal (S5-Co1) or intercoccygeal (Co1-Co2) space. Heart rate, respiratory rate and rectal temperature were recorded prior to and during analgesia at 5, 10, 15, 30 and 60 minutes. Furthermore, depth and duration of analgesia were evaluated during surgical intervention.The study revealed that the combination of epidural xylazine-lidocaine with xylazine sedation was highly satisfactory for surgery of the lower urinary tract and the perineal region, but it was less so for surgery of the umbilical area.