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排序方式: 共有332条查询结果,搜索用时 31 毫秒
1.
选择 40头成年阉牦牛 ,( 2 0头为试验组、2 0头为对照组 ) ,进行围栏草地上短期放牧育肥试验。结果 ,在围栏草地上放牧育肥的试验组阉牦牛 ,试验组每头牦牛的总增重比对照组提高 3 .3 1kg ,平均日增重 83g ,提高 44 % ,(P <0 .0 1)。试验组比对照组牦牛每头分别增收 2 6.48元  相似文献   
2.
西杂牛连续埋植“畜大壮”效果观察   总被引:1,自引:1,他引:0  
本试验对甘肃河西地区西杂1-2岁和周岁以下的犊牛连续用促生长剂“畜大壮”分阶段进行耳根埋植,试验结果表明,4-6月龄犊牛全期180天,试验组增重和平均日增重分别为5.5kg和308.33g,试验组比对照组提高37.25kg和206.94g(P〈0.01),1-2岁牛全期180天,试验组平均增重和日增重分别为56.43kg和314.49g,试验缄比对照组分别提高30.03kg和166.82g差异显著  相似文献   
3.
Linear models were developed and evaluated for the estimation of daily (24 h) and total lactation milk yield of dairy sheep from single morning (am) or evening (pm) milking records. A total of 22,908 individual test-day milk records of 5110 ewes of the Chios breed, raised in 46 flocks, were used. Depending on the model, different daily milk yield estimates were derived for each ewe, accounting for lactation number, stage of lactation, season of previous lambing and interval between successive milkings. Daily milk yield was also estimated from doubling the single am or pm record. Actual and estimated yields were compared using root mean square errors (RMSEs), mean absolute differences, an accuracy parameter defined as the ratio of the actual yield variance over the sum of the variances of actual yield and absolute difference, and the product moment correlation between estimated and actual yield. Results were validated on independent datasets. Linear models resulted in less biased and more accurate estimates of the daily milk yield than simply doubling the am or pm record. Root mean square errors decreased by 7-37% and the mean absolute difference was reduced by 1-4% of the average daily yield. Higher accuracy and correlation were obtained from linear model application than doubling. Total lactation milk yield was predicted based on actual daily yield and compared to predictions based on estimated daily yield from am or pm records, as well as directly on single milking records. Root mean square errors obtained when daily yield had been estimated with linear models were 26-35% lower compared to doubling the am or pm yield and 0-13% lower compared to estimating the total lactation yield directly from single milking records. Linear model application also resulted in lower mean absolute difference and higher accuracy and correlation than doubling the am or pm record. Recording the yield of a single milking (am or pm) instead of both can benefit milk recording by reducing its cost and increasing farmer participation. In this context, linear models developed in the present study can be used for the accurate estimation of daily (24 h) and total lactation milk yield from single milking records.  相似文献   
4.
郭泾利 《中国牛业科学》2011,37(4):59-60,69
为今后奶牛改良工作成果的巩固和推广提供依据,对国家奶牛良种补贴项目在泾阳实施的效果与措施进行总结.结果表明:累计使用良种冷冻精液细管23.7万支,生产改良奶牛3.15万头,且已有1.1万头的优质母牛已正式进入产奶阶段.良种补贴后代奶牛的头胎日产奶量达到27 kg左右,比同期母亲日产奶量高2 kg~3 kg;生奶平均乳...  相似文献   
5.
A cost-efficient light control system based on weather forecasts, electricity prices and daily photosynthesis integral (DPI) was evaluated for application in the commercial production of the long-day (LD) plant Campanula portenschlagiana ‘Blue Get Mee’ and C. cochlearifolia ‘Blue Wonder’. Experiments were conducted under both autumn and spring conditions and included four treatments. Three treatments were controlled by the software system DynaLight Desktop which automatically defined the most cost-efficient use of supplemental light, -based on a predefined set point of DPI, forecasted solar irradiance and the market price on electricity. The set points of DPI in the three treatments were 300, 450 and 600 mmol CO2 m−2 leaf d−1 and the treatments were compared with a traditional LD 19-h treatment. The DPI-based light control strategy resulted in very irregular light patterns including daily periods of solar irradiance combined with supplemental light in low light periods and a night period interrupted by irregular light breaks (NB-lighting). Both campanula species flowered in the DPI-based treatments during spring, but the flowering percentage was low and non-uniform during autumn. This was caused by a combination of the irregular light, low natural light intensities and a decrease in daily light integral (DLI), and could be restored by maintaining a continuous 19 h photoperiod with incandescent lamps (<5 μmol m−2 s−1), illustrating that photoperiod was an important factor for flowering in LD species grown under low light intensities. Growth in terms of carbon gain was marginally affected by the irregular light and a 25% reduction in electricity costs was achieved without major reductions in plant quality in spring. Our results illustrate that plant production of LD species can be maintained in a cost-efficient light control system where the use of supplemental light is based on weather forecasts and electricity prices.  相似文献   
6.
精料补充料在家兔日粮中的应用研究   总被引:2,自引:1,他引:2  
选择35日龄左右、健康无病的齐卡大型白兔120只,随机分为4组,分别饲喂全价饲料和3种不同营养水平的精料补充料,观察其采食量、日增重和成活率。结果表明:饲喂青草加精料补充料较饲喂全价饲料成本低。而精料补充料以消化能12.76MJ/kg、粗蛋白19.28%、粗纤维6.21%的营养水平饲喂效果最佳。  相似文献   
7.
[目的]探讨非洲淡水鳉鱼的生存要素和日常管理。[方法]以贡氏假腮鳉为例,从水质、水温、光照和日常管理等方面来探讨贡氏假腮鳉的生存要素和日常管理。[结果]贡氏假鳃鳉幼鱼对水质和水温的要求很高。若水温过低,幼鱼的生病几率会大大增加,还可能出现畸变情况。另外,光照对成鱼的色彩也有很大影响。[结论]在贡氏假鳃鳉的日常饲养中,水中的溶氧量一般保持在6 mg/L以上。  相似文献   
8.
中国荷斯坦奶牛产奶量与乳品质互作关系探讨   总被引:2,自引:0,他引:2  
以一个奶牛场的336头泌乳牛为研究对象,选取了降低产奶量前、降低产奶量期间、恢复产奶量期间和提高产奶量期间4个阶段,研究了每个阶段的产奶量与乳品质一些指标间的相关性。经分析,产奶量、乳蛋白质率、乳脂肪率、非脂乳固体含量、乳糖含量这5个指标相互之间均有极显著的正相关性。  相似文献   
9.
羔羊30日龄早期断乳及代乳料研究   总被引:1,自引:0,他引:1  
[目的]提高羊只的生产性能。[方法]根据母羊的泌乳曲线和羔羊的生长发育规律,配制标准营养水平(试验1组)和低于标准营养水平15%(试验2组)的代乳料对30日龄羔羊进行早期断乳试验,以正常断乳(90日龄)为对照,比较不同试验组羔羊的日增重和饲料转化率及母羊的发情情况。[结果]试验1组和试验2组羔羊日增重和料重比均高于对照,30-90日龄2组羔羊的日增重分别为164.6、159.4 g,分别与对照(日增重118.7g)达到极显著和显著差异水平;试验1组和试验2组母羊发情较早,分别为51、54 d,对照组母羊平均发情期为66 d。[结论]羔羊早期断乳可使母羊的发情提早12-15 d。  相似文献   
10.
选用西宁市奶牛场荷斯坦育肥牛 1 6头 ,随机分为试验组和对照组 ,每组为 8头。试验组饮喂 1 50 ppm甲醛液 ,对照组饮自来水。试验期 50天。结果表明 ,试验组和对照组平均增重分别为 51 .0 0千克和 2 8.50千克 ,日增重分别为 1 0 2 0克和 570克 ,差异极显著 (p<0 .0 1 )。  相似文献   
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