The objective of this study was to characterize the rumination time in lactating dairy cows fed with corn silage.Rumination time was recorded 24 h/day using direct visual observation.Six trials were conducted during 2...The objective of this study was to characterize the rumination time in lactating dairy cows fed with corn silage.Rumination time was recorded 24 h/day using direct visual observation.Six trials were conducted during 2018,2019 and 2020,and rumination time was recorded in 480-2-hour periods from 40 Holstein Friesian cows.In each trial,6 or 8 cows were selected and balanced for days in milk(DIM),milk production and number of lactations.Each cow was recorded continuously for periods of 2 h at a time to complete a full 24-h period per week(12 values per day).Data from all cows were associated with 4 reproductive statuses of cows:Inseminated(1-45 days after insemination),Open(45-150 days after calving),not-pregnant and pregnant.The longest rumination time(RT)was found in pregnant cows(average 536.9±29.87 min/day),and the shortest RT was in open cows(average 420.3±63.2 min/day).Inseminated and non-pregnant cows were found with intermediate values(527.3±82.4 min/day and 467.1±30.7 respectively).Significantly different RT means were found between pregnant and open cows(p<0.0001),pregnant vs.inseminated cows(p<0.0001),and between inseminated and open cows(p=0.0005).We concluded that some gynecological conditions of lactating cows affect the RT.Measurement of RT by visual observations proved to be acceptable for the conditions of this study when cows were housed indoors and were fed with partial mixed ration(PMR)based on corn silage.展开更多
文摘暴雨云团的宏微观结构在不同地理环境和环流背景下表现出明显差异。黄河流域内蒙古段地处半干旱区,地形复杂,暴雨突发性强。利用风云三号G星(FY-3G)卫星搭载的降水测量雷达(Precipitation Measurement Radar,PMR)数据,结合欧洲中期天气预报中心(European Center for Medium-Range Weather Forecasts,ECMWF)的ERA5再分析资料,对2024年8月8日黄河流域内蒙古段暴雨过程的云团三维结构及环流背景进行综合分析。结果表明,暴雨发生在副热带高压与西风槽共同作用的环流背景下,700 hPa低空急流、明显的垂直风切变以及暖湿气流的强上升运动为暴雨形成提供有力动力条件。降水云系中同时存在层状云与对流云,对流云的平均粒子数浓度、有效粒子直径、降水率均高于层状云,且粒子数浓度和有效粒子直径的垂直分布与不稳定能量场高度一致;降水反射率在0℃层上下存在高频增强区,对流云在约5 km高度的潜热释放量是层状云的2倍,表明对流云团是此次极端暴雨的主要贡献者,对降水效率和降水强度具有决定性影响。云顶高度自西向东逐渐升高,极端暴雨区的云顶高度及0℃层高度的水平分布特征与地形起伏密切相关。
文摘The objective of this study was to characterize the rumination time in lactating dairy cows fed with corn silage.Rumination time was recorded 24 h/day using direct visual observation.Six trials were conducted during 2018,2019 and 2020,and rumination time was recorded in 480-2-hour periods from 40 Holstein Friesian cows.In each trial,6 or 8 cows were selected and balanced for days in milk(DIM),milk production and number of lactations.Each cow was recorded continuously for periods of 2 h at a time to complete a full 24-h period per week(12 values per day).Data from all cows were associated with 4 reproductive statuses of cows:Inseminated(1-45 days after insemination),Open(45-150 days after calving),not-pregnant and pregnant.The longest rumination time(RT)was found in pregnant cows(average 536.9±29.87 min/day),and the shortest RT was in open cows(average 420.3±63.2 min/day).Inseminated and non-pregnant cows were found with intermediate values(527.3±82.4 min/day and 467.1±30.7 respectively).Significantly different RT means were found between pregnant and open cows(p<0.0001),pregnant vs.inseminated cows(p<0.0001),and between inseminated and open cows(p=0.0005).We concluded that some gynecological conditions of lactating cows affect the RT.Measurement of RT by visual observations proved to be acceptable for the conditions of this study when cows were housed indoors and were fed with partial mixed ration(PMR)based on corn silage.
