Efficiency of a pedometer device for detecting estrus in standing heat and silent heat in Japanese Black cattle

The usefulness of a radiotelemetric pedometer for estrus detection in standing (ST) heat, or in silent heat without ST events, but in which ovulation is observed, in Japanese Black cattle was investigated. The duration of an increase in steps in ST heat was 11.8 ± 1.3 hr, and it was similar to that of ST events (duration: 10.1 ± 0.8 hr). Even in silent heat, the change pattern and the duration (11.6 ± 0.2 hr) of the period with an increase in steps during estrus were not different compared with ST heat. When artificial insemination (AI) was performed at 15.5 ± 0.6 hr from the onset of estrus detected by the pedometer in ST heat cases, the conception rate was 57.1% (8/14). Furthermore, fertility in cattle that underwent silent heat was evaluated. When AI was performed at 14.4 ± 2.0 hr from the onset of estrus detected by the pedometer, the conception rate was 60% (3/5) in silent heat cases. The overall results suggest that the radiotelemetric pedometer is a valid device for detecting estrus and it can even detect silent heat in Japanese Black cattle. Moreover, even silent heat cattle are fertile when AI is performed at the appropriate time.     

Experimental infection of pups with Ancylostoma caninum-infected mouse tissues

Migration and distribution of Ancylostoma caninum larvae in the tissues of mice orally infected with 1000 larvae, and establishment of patent infection from the mice to the definitive host, were studied. Larval yield from different organs of mice, after digestion with artificial gastric juice, indicated that the highest recovery was at 4 h post-infection (62.8%), and thereafter a slight decline occurred up until 30 days post-infection (51.5%). Migration of larvae to the lungs occurred within 4 h, to the liver within 12 h and into the heart within 24 h. No larvae were recovered from spleen and kidney tissues. From the 9th day onwards larvae were also recovered from the brain. Migration in the muscles of head and neck occurred within 4 h, in the thoracic and abdominal muscles at 24 h and in lumbosacral and leg muscles at 48 h. The establishment of patent infections in the definitive host was studied by feeding the orally- and percutaneously-infected mice to hookworm-free pups at 10 and 30 days post-infection. The mean necropsy worm burden in the pups fed with the orally-infected mice was comparatively higher than in the pups fed cutaneously-infected mice.     

大黄素甲醚、大黄酸的研究进展

2014年世界卫生组织首份全球抗菌素耐药报告显示全世界面临严重的公共卫生威胁,2021年农业农村部制定了《全国兽用抗菌药使用减量化行动方案》(2021-2025),从国家层面实施综合治理策略和措施,鼓励替代抗菌药物的研制和创新。大黄素甲醚、大黄酸作为植物蒽醌类有效成分,具有抗微生物、抗炎、抗氧化、神经保护等药理作用,但对其抗菌、抗病毒、抗炎症相关的作用机制和产业化工艺缺少详细报道。本文对国内外已经发表的专利文献、期刊文献进行综述,总结其抗菌、抗病毒、抗炎作用机制及其生产工艺,以期为进一步开发利用提供科学支撑。     

Fertility of Holstein cows and heifers submitted to timed artificial insemination and receiving one or two doses (12 h apart) of semen

The objective of this retrospective study was to assess the effect of receiving a single (n = 50,285) or double (n = 4392) artificial insemination (AI), 12 h apart, within a timed artificial insemination protocol on pregnancy per AI (P/AI) in nulliparous heifers (inseminated with either sex-sorted or conventional semen) and pluriparous Holstein cows in a commercial dairy herd. Also, this study aimed to investigate the relationship between temperature-humidity index (THI) and time of the first AI and fertility. Fertility of cows receiving two AI with normothermia (THI <68) was higher (p < .05) than cows receiving a single AI (42.9% vs. 36.4%). P/AI of cows receiving two AI with severe heat stress (THI >85) was higher (p < .05) than cows receiving a single AI (21.0% vs. 12.6%). Regardless of heat stress conditions, applying the first AI in the morning increased (p < .05) P/AI in cows with double AI than in cows whose first AI occurred in the afternoon (38.4 vs. 33.3%). With moderate heat stress, and sexed-sorted semen, P/AI to timed AI was higher (65.0 vs. 51.9%; p < .05) in heifers receiving double AI than those serviced once. It was concluded that double AI, 12 h apart, enhanced fertility at timed AI than herd mates with a single AI, particularly with heat stress at breeding.     

Isolation of Pasteurella haemolytica and correlation with serum antibody response in clinically normal beef calves

Bacteria from the nasal cavity and trachea were cultured, and serum antibody titers determined for Pasteurella haemolytica serotype 1 in 164 beef calves obtained from a closed herd on range pasture. At the first sampling, P. haemolytica serotype 1 was cultured from 16.4% of the calves. Antibody titers were determined by a quantitative fluorimetric method and the mean titer was 9.5 +/- 5.8. Fifty-seven randomly selected calves were used to study the correlation of serum antibody response and positive culture of P. haemolytica under natural conditions. Clinical signs of respiratory disease were not observed in those calves. During the observation periods, there was a two-fold increase in the percentage of calves that were culture positive. There was no significant difference between mean serum antibody titers or frequency distribution of antibody titers from the two samplings. Comparisons between serum antibody titers, rise in titers, and P. haemolytica isolation failed to reveal any significant correlation. Of the 9 calves that had a decline in antibody titer to P. haemolytica, none was culture positive. Seroconversion to respiratory viruses did not correlate with P. haemolytica related variables.     

杀菌温度对优质巴氏杀菌乳中热敏感和生物活性物质的影响

选取我国东南某乳品企业特优级(A+)生乳,采用不同巴氏杀菌温度74℃、75℃、76℃、77℃、78℃、79℃和80℃(15 s保持时间),检测杀菌乳中的热敏感物质糠氨酸、碱性磷酸酶、乳过氧化物酶和乳中生物活性物质免疫球蛋白、乳铁蛋白、ɑ-乳白蛋白、β-乳球蛋白的含量。试验结果显示,优质乳在74℃和75℃杀菌条件下活性物质变化不大,杀菌温度从76℃提高至80℃的过程中,随着杀菌温度的升高,乳中活性成分急剧降低。综合分析,优质巴氏杀菌乳的生产推荐采用75℃/15 s的温度时间组合,为行业同类产品生产参数的选取提供了参考。     

Annual Energy Consumption and Feasibility Assessment of Ground -Source Heat Pump in Residential Building in Fuzhou City

This paper describes the annual energy consumption and economic assessment of air-source heat pump(ASHP) and ground-source heat pump(GSHP),based on hourly building load of typical house in Fuzhou.Analysis results show that the energy consumption of GSHP is 15% less than that of ASHP through all year,where there is 13% less in summer and 20% less in winter.Although the seasonal energy efficiency ratio of GSHP in Fuzhou is higher than that of ASHP,it has no obvious effect on the energy efficiency as it is in the hot summer and cold winter zone.In comparison with ASHP,the GSHP is not cost-effective.     

长期饲喂高精料日粮对泌乳期山羊血液生化参数及组织中糖代谢相关基因表达的影响

为了研究长期饲喂高精料日粮对泌乳期山羊血液生化指标和糖代谢的影响,选择8只安装永久性瘤胃瘘管的健康经产泌乳中期山羊,分别饲喂精粗比为40∶60 (low concentrate, LC,n=4) 和60∶40 (high concentrate, HC,n=4)的日粮。实验期共8周,实验期间采集瘤胃液,血液;实验结束时采集肝脏,肌肉,脂肪组织置于液氮速冻后于-70℃保存待测。结果显示,饲喂高精料日粮2周后山羊瘤胃液pH显著降低,采食后瘤胃液pH持续低于5.8超过3 h,8周后瘤胃液pH升高维持在6.0以上,但仍低于LC组山羊。与LC组山羊相比较,HC组山羊血液中葡萄糖、游离脂肪酸含量均升高(P<0.05,P=0.071),谷草转氨酶含量有上升的趋势(0.05相似文献   

持续高温应激对肥育猪生产性能、胴体性状、背最长肌营养物质含量及肌纤维特性的影响

本试验旨在研究持续30℃的环境高温应激对肥育猪生产性能、胴体性状、背最长肌质构分析、营养物质含量及肌纤维特性的影响.试验选取8窝共24头体重为(79.0±1.5) kg的“杜长大”三元阉公猪,其中每3头来自同一窝的猪只随机分到3组,每组8个重复,每个重复1头,3组分别为对照组(22℃适温+自由采食)、高温应激组(30℃高温+自由采食)和采食量配对组(22℃适温+采食量配对),试验期21d.结果表明:1)持续高温应激显著降低肥育猪平均日增重(ADG) (P＜0.05),极显著降低肥育猪平均日采食量(ADFI) (P＜0.01).2)3组之间的肥育猪胴体重、胴体长、平均背膘厚和皮厚均差异不显著(P＞0.05),高温应激组肥育猪背最长肌大理石花纹评分在宰后24 h有低于对照组的趋势(P＜0.10).3)高温应激组肥育猪背最长肌的剪切力极显著高于对照组和采食量配对组(P＜0.01).与采食量配对组相比,高温应激组肥育猪背最长肌胶黏性和硬度有降低的趋势(P＜0.10).4)高温应激组和采食量配对组肥育猪背最长肌粗蛋白质含量显著高于对照组(P＜0.05),且2组的背最长肌肌内脂肪(IMF)含量极显著低于对照组(P＜0.01).5)高温应激组肥育猪背最长肌Ⅰ型肌纤维含量有低于采食量配对组的趋势(P＜0.10),采食量配对组的Ⅱx型肌纤维含量显著低于对照组(P＜0.05).由此可见,肥育后期高温应激会改变猪表观肉品质和肌肉营养物质含量.