饲养模式对科尔沁肉牛育肥性能的影响

[目的]为研究饲养模式对科尔沁肉牛育肥性能的影响,特开展本试验研究,以期为农牧民提供饲养育肥牛的技术指导。[方法]选取体重体型均等的科尔沁肉牛架子牛120头,随机分为试验组1、试验组2与对照组,每组各40头。试验组1根据资料与经验制定为期185 d的饲养方案1,试验组2对养殖户自有饲养模式的饲料量与精粗配比优化后制定为期245 d的饲养方案2,对照组按照养殖户以往模式进行饲养,育肥期结束后称量体重,计算各组日增重数据。[结果]结果显示,试验组2的增重比试验组1与对照组分别提高37.2%与6.4%;试验组2与对照组的饲料利用率显著低于试验组1;经济效益方面试验组2的效益高于试验组1与对照组。结果表明试验组2为较合适的育肥牛饲养模式。[结论]试验证明,制定科学、系统的饲养模式,以合理的育肥时长、饲料摄入及精心的饲养管理,能够提高科尔沁肉牛育肥牛的育肥性能并获得更高的经济效益。     

减缓肉牛热应激最新研究进展

为了减少肉牛热应激对肉牛生产性能、生理生化指标、抗氧化能力、妊娠牛激素及免疫功能等方面产生的影响,笔者检索了国内外相关文献,从品种、中草药方剂和饲料添加剂、环境控制三方面归纳在肉牛抗应激能力的最新研究进展,为肉牛健康高效养殖提供参考。     

皮南牛新品种培育现状、存在问题与对策

南阳牛是我国五大良种黄牛品种之一,近些年国家越来越重视通过杂交改良的方法产生新品种培育工作,1986年引进了皮埃蒙特牛,与南阳牛进行杂交改良,通过30多年来的持续选育,横交固定形成了皮南牛新类群,它保持了南阳牛适应性好、耐粗饲的优点,同时继承了皮埃蒙特牛生长发育快、瘦肉率高的特点,但在皮南牛新品种培育过程中,仍存在核心群数量不足、整齐度较低等问题,本文探讨了皮南牛新品种培育工作的现状、存在问题及对策。     

肉牛口蹄疫灭活苗不同免疫程序免疫效果的比较

为了解肃南地区肉牛口蹄疫免疫动态,达到为本地区肉牛养殖制定科学口蹄疫免疫程序的最终目的。本文与2019年3月份采用随机抽样方法选取120头肉牛,分成了3组,分别采取不同免疫程序,根据免疫抗体检测水平的变化,选择免疫效果最佳的免疫程序。试验结果表明,第3组的口蹄疫A型、O型抗体水平最高。因此,本试验推荐肉牛场每年免疫3～4次O型和Asia I型二价口蹄疫灭活疫苗。     

郏县红牛皮肤真菌病的流行性调查及治疗体会

本文以场内生产情况为例,记录了牛皮肤真菌病的症状、治疗及诊断和防治措施,以期给同行提供参考,共同探讨。     

Short communication: investigation of the feasibility of genomic selection in Icelandic Cattle

Icelandic Cattle is a local dairy cattle breed in Iceland. With about 26,000 breeding females, it is by far the largest among the indigenous Nordic cattle breeds. The objective of this study was to investigate the feasibility of genomic selection in Icelandic Cattle. Pedigree-based best linear unbiased prediction (PBLUP) and single-step genomic best linear unbiased prediction (ssGBLUP) were compared. Accuracy, bias, and dispersion of estimated breeding values (EBV) for milk yield (MY), fat yield (FY), protein yield (PY), and somatic cell score (SCS) were estimated in a cross validation-based design. Accuracy (r^) was estimated by the correlation between EBV and corrected phenotype in a validation set. The accuracy (r^) of predictions using ssGBLUP increased by 13, 23, 19, and 20 percentage points for MY, FY, PY, and SCS for genotyped animals, compared with PBLUP. The accuracy of nongenotyped animals was not improved for MY and PY, but increased by 0.9 and 3.5 percentage points for FY and SCS. We used the linear regression (LR) method to quantify relative improvements in accuracy, bias (Δ^), and dispersion (b^) of EBV. Using the LR method, the relative improvements in accuracy of validation from PBLUP to ssGBLUP were 43%, 60%, 50%, and 48% for genotyped animals for MY, FY, PY, and SCS. Single-step GBLUP EBV were less underestimated (Δ^), and less overdispersed (b^) than PBLUP EBV for FY and PY. Pedigree-based BLUP EBV were close to unbiased for MY and SCS. Single-step GBLUP underestimated MY EBV but overestimated SCS EBV. Based on the average accuracy of 0.45 for ssGBLUP EBV obtained in this study, selection intensities according to the breeding scheme of Icelandic Cattle, and assuming a generation interval of 2.0 yr for sires of bulls, sires of dams and dams of bulls, genetic gain in Icelandic Cattle could be increased by about 50% relative to the current breeding scheme.     

全株青贮小麦秸秆饲喂肉牛增重效果的试验研究

[方法]采用全舍饲饲喂方式,对改良肉牛开展全株青贮小麦秸秆饲喂增重效果的试验研究。[结果]结果表明,在其他饲养条件完全一致的情况下,用全株青贮小麦秸秆饲喂肉牛,头均增重达18.5 kg,较全株玉米秸秆对照组提高33%,头均盈利358.68元,盈利提高78.76%,经济效益明显。     

基于改进动态时间规整算法的奶牛步态分割方法

为准确提取步态特征、识别奶牛跛行,利用三维加速度传感器采集30头奶牛后趾加速度信号,针对奶牛步态人工分割的不足,提出基于改进的动态时间规整算法对奶牛步态进行分割,提取特征值并利用逻辑回归法建立跛行识别模型。采用本文方法得到的步态分割精确度、灵敏度、准确率平均值分别为89.53%、95.51%、87.49%,比常规动态时间规整算法分别提高了5.31、4.48、8.43个百分点,总体准确率达到90.57%,相较自相关函数法和峰值检测法分别提高了1.75、3.13个百分点。以支撑时间、步幅长度、平均强度、信号幅度面积、前进方向加速度均值和运动变化量为自变量的跛行识别模型识别率分别为83.44%、81.72%、86.15%、86.81%、89.45%和85.71%。本研究结果可为奶牛步态分割、跛行识别提供技术支持。     

A review of thermal stress in cattle

Cattle control body temperature in a narrow range over varying climatic conditions. Endogenous body heat is generated by metabolism, digestion and activity. Radiation is the primary external source of heat transfer into the body of cattle. Cattle homeothermy uses behavioural and physiological controls to manage radiation, convection, conduction, and evaporative exchange of heat between the body and the environment, noting that evaporative mechanisms almost exclusively transfer body heat to the environment. Cattle control radiation by shade seeking (hot) and shelter (cold) and by huddling or standing further apart, noting there are intrinsic breed and age differences in radiative transfer potential. The temperature gradient between the skin and the external environment and wind speed (convection) determines heat transfer by these means. Cattle control these mechanisms by managing blood flow to the periphery (physiology), by shelter-seeking and standing/lying activity in the short term (behaviourally) and by modifying their coats and adjusting their metabolic rates in the longer term (acclimatisation). Evaporative heat loss in cattle is primarily from sweating, with some respiratory contribution, and is the primary mechanism for dissipating excess heat when environmental temperatures exceed skin temperature (~36°C). Cattle tend to be better adapted to cooler rather than hotter external conditions, with Bos indicus breeds more adapted to hotter conditions than Bos taurus. Management can minimise the risk of thermal stress by ensuring appropriate breeds of suitably acclimatised cattle, at appropriate stocking densities, fed appropriate diets (and water), and with access to suitable shelter and ventilation are better suited to their expected farm environment.     

牛多杀性巴氏杆菌未知型的分离鉴定及防治

以病死牛病变肺脏组织为研究对象，通过革兰氏染色和PCR鉴定确定多杀性巴氏杆菌分离株的血清型，进行分离菌株的小鼠致病性试验和药敏试验。结果表明：该分离菌株为未知型多杀性巴氏杆菌，对硫酸阿米卡星、左氧氟沙星、硫酸庆大霉素、乳酸环丙沙星高度敏感；小鼠多杀性巴氏杆菌最小致死量为1.2×10⁸CFU/m L。