鲁西牛的染色体研究

研究了40头鲁西牛(♂37,♀3,2n=60)染色体的 G 带,R 带,C 带及Ag-NOR,着重分析了 y 染色体的形态及带型。在常规 Giemsa 染色的分裂相上,y染色体和小的常染色体形态相近。经常规—C 带连续染色,准确识别出 y 染色体之后测量了18条 y 染色体,臂比为3.19,属亚端着丝点染色体。y 染色体的着丝点区和短臂与常染色体的着丝点区和短臂在 G 带、C 带的带型上差别很大,表明构成它们 DNA的硷基成份有差别。统计的152个细胞的 Ag-NOR 中,平均每细胞 Ag-NOR 数为5.81±1.38,变化范围2—9。按染色体长度排列,NOR 位于2、3、4、11、22(或21)和28号常染色体末端。第22(或21)号染色体上存在 NOR 在其它牛种上尚未有过报道。     

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。     

青海黄牛血清运铁蛋白多态性研究

采用聚丙烯酰胺凝胶电泳法对１００头青海黄牛的血清运铁蛋白多态性进行了研究。结果发现：青海黄牛血清运铁蛋白位点存在ＴＦ￣Ａ，ＴＦ￣Ｂ，ＴＦ￣Ｄ１，ＴＦ￣Ｄ２，ＴＦ￣Ｆ，ＴＦ￣Ｅ６个等位基因，总共构成１３个基因型。与国内１２个品种黄牛的遗传距离和聚类分析表明，青海黄牛与蒙古牛的亲缘关系最近（Ｄｍ＝０．１１７８）。     

快速凝集试验与补体结合试验检测牛边缘无浆体感染的效果对比

从138份血清样品的比较试验结果显示，快速凝集试验（RCA）比补体结合试验（CF）检测边缘无浆体感染的敏感性高（88．9％：81．5％），假阴性率低（11．1％：18．5％），两者都具有良好的特异性和预测性，检测阳性符合率高，快速凝集试验对一次感染牛的持续检出阳性时间更长久（303天：92天）     

Breeding distribution and maternal genetic lineages in Lulu,a dwarf cattle population in Nepal

Lulu is a dwarf cattle population bred in the Mustang district of western and central Nepal. This area is located around the habitat boundary between Bos taurus and Bos indicus. The peculiarities of Lulu are their small size (weight range in the adult female: 68–153 kg) and rearing in high mountain areas at 2800 m to 4000 m in altitude. There were 5770 head of Lulu cattle in the Mustang district in 1998, 4333 females and 1437 males. The morphological appearance of Lulu is Bos taurus. However, one of the five Lulu studied in Kagbeni, Mustang had a Bos indicus mitochondrial DNA type based on the D‐loop sequence, while the other four were Bos taurus. It is suggested that there are hybrids of Lulu with Bos indicus maternal lineage in a mostly taurine‐breed genetic background. Steps must be taken to preserve the unique Lulu.     

肉用种公牛的后裔测定

肉牛育种工作中对种公牛种用价值最终认定是通过后裔测定完成的。同期同龄比较法是在过去和将来采用并将继续使用的较为普遍的方法。随着动物育种技术的进展以及计算机技术、生物技术的不断革新和完善,ＢＬＵＰ、ＭＯＥＴ和ＩＶＦ技术和手段已应用于肉牛育种,因此肉牛的后裔测定方法也将随之改进。本文介绍肉用种公牛四种后裔测定方法。     

张掖地区围栏育肥牛场防风墙后不同风速对肉牛场环境及肉牛生产性能的影响

本试验旨在研究防风墙在不同遮蔽距离的减风效果以及风速对牛生产性能的影响。选取初始体重差异不显著的40头牛随机平均分布在选定的4个牛栏中,根据牛栏距防风墙的远近分为2组,测定其日增重。同时根据牛场实际条件和天气状况布置测点,对测点的风速、温度等其他环境指标和肉牛的产热进行现场实测与计算分析。结果表明:安装防风墙的围栏育肥牛场在墙后1.2 m高度,水平遮蔽距离10倍墙高的范围内,可折减风速40%～70%;防风墙后的最佳遮蔽区域是在距离防风墙2～4倍墙高处、水平遮蔽距离6倍墙高距离范围内,风速折减效果明显,最大折减率可达70%左右;肉牛平均体重为480 kg,在外部风冷指数为-15.61的条件下,安装防风墙的围栏育肥牛场的风冷指数可以降低到-9.00,每头牛每小时可减少热量损失3.31 MJ;由于距离防风墙的远近不同,肉牛日增重相差0.15 kg/(头·d),但差异不显著(P>0.05)。     

Pathological characteristics of thyroid glands from Japanese Black Cattle living in the restricted area of the Fukushima Daiichi Nuclear Power Plant accident

To study the effect of ionizing radiation on thyroid glands, 66 Japanese Black cattle residing in the restricted area of the Fukushima Daiichi Nuclear Power Plant in 2013–2017 were pathologically examined. There were no clinical symptoms of thyroid disease in these cattle. Three cases of goiter and seven of atrophy were found in two among the four farms examined. Cases of goiter exhibited normal morphological structure without mass or nodule formation in thyroid glands. Cellular atypia or capsular invasion of the follicular epithelium was absent. The estimated integrated dose of external radiation in goiter cases ranged from maximum 797 mSv to minimum 24 mSv. All lobules in the seven atrophic thyroid glands were affected, but pathological findings, such as inflammatory cell infiltration or stromal fibrosis, were not observed. The estimated integrated dose of external radiation in atrophic thyroids ranged from maximum 589 mSv to minimum 8 mSv. Immunohistochemical analysis of anti‐nitroguanosine and the TUNEL method in goiter and atrophic thyroid glands did not reveal any positive findings. The present study indicates that there was no significant relationship between a radiation effect and pathological findings in any thyroid glands.     

Comparison of urine and blood as a convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium

Blood and urine were compared to clarify which is a better sample for estimating the concentration of radioactive cesium in muscles of live cattle. The most probable concentration of ¹³⁷Cs in muscles was 21.0 times that in blood, and the error of this estimation was 28%. The concentration of ¹³⁷Cs in blood was estimated accurately using urine samples. The estimation error did not increase so much (33%), even when the concentration of ¹³⁷Cs in muscles was estimated using urine samples. On the other hand, the maximum volume of blood that can be collected with one syringe is 50 ml, whereas it is easy to collect 1,000 ml of urine. It took at least 360 min to confirm that a cow meets the legal standard by inspecting 50 ml of blood. However, with 1,000 ml of urine, a 20 min measurement time was sufficient for this purpose. This difference in the required measurement time is critically important for practical use. In addition, urine can be collected by farmers themselves, whereas the blood collection requires a veterinarian. Therefore, urine is a more convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium.     

Across-breed validation study confirms and identifies new loci associated with sexual precocity in Brahman and Nellore cattle

The aim of this study was to identify candidate regions associated with sexual precocity in Bos indicus. Nellore and Brahman were set as validation and discovery populations, respectively. SNP selected in Brahman to validate in Nellore were from gene regions affecting reproductive traits (G1) and significant SNP (p ≤ 10^–3) from a meta-analysis (G2). In the validation population, early pregnancy (EP) and scrotal circumference (SC) were evaluated. To perform GWAS in validation population, we used regression and Bayes C. SNP with p ≤ 10^–3 in regression and Bayes factor ≥3 in Bayes C were deemed significant. Significant SNP (for EP or SC) or SNP in their ±250 Kb vicinity region, which were in at least one discovery set (G1 or G2), were considered validated. SNP identified in both G1 and G2 were considered candidate. For EP, 145 SNP were validated in G1 and 41 in G2, and for SC, these numbers were 14 and 2. For EP, 21 candidate SNP were detected (G1 and G2). For SC, no candidate SNP were identified. Validated SNP and their vicinity region were located close to quantitative trait loci or genes related to reproductive traits and were enriched in gene ontology terms related to reproductive success. These are therefore strong candidate regions for sexual precocity in Nellore and Brahman.