为了筛选适用于规模化牛场的最佳肉牛定时输精方案,探究定时输精技术对经产母牛繁殖性能的影响,试验将膘情良好且子宫、卵巢发育良好的产后未观察到自然发情的不同胎次西门塔尔母牛111头随机分为试验1,2,3,4组,每组分别为30,28,28,25头...为了筛选适用于规模化牛场的最佳肉牛定时输精方案,探究定时输精技术对经产母牛繁殖性能的影响,试验将膘情良好且子宫、卵巢发育良好的产后未观察到自然发情的不同胎次西门塔尔母牛111头随机分为试验1,2,3,4组,每组分别为30,28,28,25头,分别采用4种不同定时输精方案(双同期-11、G-6-G、G P E和G P A法)进行处理,测定同期发情率、情期受胎率、产后空怀天数、体况评分(BCS)等指标,用于评价不同方案的输精效果,同时分析了不同胎次和体况评分对输精效果的影响。结果表明:试验1组(双同期-11法)情期受胎率最高,为68.97%,显著高于其他组的41.67%~48.15%(P<0.05);体况评分5分组的情期受胎率最低,为16.67%,与体况评分7分组差异显著(P<0.05),与体况评分6分组差异极显著(P<0.01);3胎次及以上组情期受胎率最低,为35.29%,与1,2胎次组差异显著(P<0.05),且2胎次发情头数最多。说明试验1组(双同期-11法)定时输精方案效果最好,体况评分为6〜7分的母牛情期受胎率较高,且胎次对定时输精效果影响较为明显。展开更多
The live cattle eye muscle area, back-fat thickness, height of eye muscle and intramuscular fat content were determined by ultrasonic technology. The prediction model for meat production performance was established. T...The live cattle eye muscle area, back-fat thickness, height of eye muscle and intramuscular fat content were determined by ultrasonic technology. The prediction model for meat production performance was established. The numerical value had high reliability and accuracy, which reached extremely significant difference via analysis of variance. The study provides scientific basis for breeding and meat evaluation of beef cattle.展开更多
The use of nitrogen(N) fertilizers has contributed to the production of a food supply sufficient for both animals and humans despite some negative environmental impact.Sustaining food production by increasing N use ef...The use of nitrogen(N) fertilizers has contributed to the production of a food supply sufficient for both animals and humans despite some negative environmental impact.Sustaining food production by increasing N use efficiency in intensive cropping systems has become a major concern for scientists,environmental groups,and agricultural policymakers worldwide.In high-yielding maize systems the major method of N loss is nitrate leaching.In this review paper,the characteristic of nitrate movement in the soil,N uptake by maize as well as the regulation of root growth by soil N availability are discussed.We suggest that an ideotype root architecture for efficient N acquisition in maize should include(i) deeper roots with high activity that are able to uptake nitrate before it moves downward into deep soil;(ii) vigorous lateral root growth under high N input conditions so as to increase spatial N availability in the soil;and(iii) strong response of lateral root growth to localized nitrogen supply so as to utilize unevenly distributed nitrate especially under limited N conditions.展开更多
文摘为了筛选适用于规模化牛场的最佳肉牛定时输精方案,探究定时输精技术对经产母牛繁殖性能的影响,试验将膘情良好且子宫、卵巢发育良好的产后未观察到自然发情的不同胎次西门塔尔母牛111头随机分为试验1,2,3,4组,每组分别为30,28,28,25头,分别采用4种不同定时输精方案(双同期-11、G-6-G、G P E和G P A法)进行处理,测定同期发情率、情期受胎率、产后空怀天数、体况评分(BCS)等指标,用于评价不同方案的输精效果,同时分析了不同胎次和体况评分对输精效果的影响。结果表明:试验1组(双同期-11法)情期受胎率最高,为68.97%,显著高于其他组的41.67%~48.15%(P<0.05);体况评分5分组的情期受胎率最低,为16.67%,与体况评分7分组差异显著(P<0.05),与体况评分6分组差异极显著(P<0.01);3胎次及以上组情期受胎率最低,为35.29%,与1,2胎次组差异显著(P<0.05),且2胎次发情头数最多。说明试验1组(双同期-11法)定时输精方案效果最好,体况评分为6〜7分的母牛情期受胎率较高,且胎次对定时输精效果影响较为明显。
基金Supported by Major Science and Technology Project of Xinjiang Uygur Autonomous Region(201230116-10)
文摘The live cattle eye muscle area, back-fat thickness, height of eye muscle and intramuscular fat content were determined by ultrasonic technology. The prediction model for meat production performance was established. The numerical value had high reliability and accuracy, which reached extremely significant difference via analysis of variance. The study provides scientific basis for breeding and meat evaluation of beef cattle.
基金supported by the National Basic Research Program of China (Grant No. 2009CB11860)the National Natural Science Foundation of China (Grant Nos. 31071852,30771289,and 30821003)the Special Fund for Agriculture Profession (Grant No. 200803030)
文摘The use of nitrogen(N) fertilizers has contributed to the production of a food supply sufficient for both animals and humans despite some negative environmental impact.Sustaining food production by increasing N use efficiency in intensive cropping systems has become a major concern for scientists,environmental groups,and agricultural policymakers worldwide.In high-yielding maize systems the major method of N loss is nitrate leaching.In this review paper,the characteristic of nitrate movement in the soil,N uptake by maize as well as the regulation of root growth by soil N availability are discussed.We suggest that an ideotype root architecture for efficient N acquisition in maize should include(i) deeper roots with high activity that are able to uptake nitrate before it moves downward into deep soil;(ii) vigorous lateral root growth under high N input conditions so as to increase spatial N availability in the soil;and(iii) strong response of lateral root growth to localized nitrogen supply so as to utilize unevenly distributed nitrate especially under limited N conditions.
