代乳粉对不同日龄驴驹生长性能的影响

旨在评价代乳粉对不同日龄驴驹生长性能的影响。分别选取2、3、4、5月龄出生日期、体重、胎次相近且健康状况良好的驴驹各10头,将相同月龄的驴驹随机分为试验组和对照组,每组5头,对照组驴驹随母驴哺乳,试验组驴驹饲喂代乳粉,试验期为30d。试验期间观察不同月龄驴驹的健康状况,测定并比较各月龄对照组及试验组驴驹在试验第0、10、20、30天的体重及体尺指标（体高、胸围、体斜长）,计算同月龄试验组和对照组驴驹的体重及各项体尺指标在试验期内不同时间段的日均变化值。结果表明,2月龄试验组驴驹的试验第10、20、30天体重均极显著（P〈0．01）高于对照组,5月龄试验组驴驹的试验第20天和第30天体重分别显著（P〈0．05）和极显著（P〈0．01）高于对照组（P〈0．05）,2、3、4、5月龄试验组驴驹在试验第0～10天、第10～20天、第20～30天,以及试验期间（第0～30天）的日增重均高于相应月龄驴驹的对照组;5月龄试验组驴驹的试验第10、20、30天体高均显著（P〈0．05）高于对照组,2、5月龄试验组驴驹在试验第0～10天、第10～20天、第20～30天以及试验期间（第0～30天）的体高日增长均高于相应月龄驴驹的对照组;2月龄试验组驴驹的试验第20天和第30天胸围均极显著（P〈O．01）高于对照组;3月龄试验组驴驹的试验第10、20、30天胸围均极显著（P〈O．01）高于对照组;5月龄试验组驴驹的试验第20天和第30天胸围均显著（P〈0．05）高于对照组;2、3、4、5月龄试验组驴驹在试验期间（第0～30天）的胸围日增长均高于相应月龄驴驹的对照组;2、5月龄试验组驴驹的试验第30天体斜长显著（P〈0．05）高于相应月龄驴驹的对照组,3月龄试验组驴驹的试验第10、20、30天体斜长均显著（P〈0．05）高于对照组,4月龄试验组驴驹的试验第20天和第30天体斜长均显著（P〈O．05）高于对照组,2、3A、5月龄试验组驴驹在试验第10～20天、第20～30天,以及试验期间（第0～30天）的体斜长日增长均高于相应月龄驴驹的对照组。综上提示,饲喂代乳粉能够促进驴驹的生长发育,在生产实践中利用代乳粉替代驴乳饲喂驴驹具有可行性。     

Estimation of potassium and magnesium flows in animal production in Dianchi Lake basin,China

The objectives of this study were to estimate and evaluate potassium (K) and magnesium (Mg) budgets and flows of animal production in the basin of Dianchi Lake, China. Feed sampling and farmer interviews were conducted in field surveys. The supplies of K and Mg from local and external feeds and the retention, production and excretion of animals were calculated individually for dairy cows, fattening pigs, breeding sows, and broilers and laying hens. The K and Mg flows on a regional level were estimated using the individual budgets. At the individual level, in dairy cattle, the K and Mg supplied from local feeds accounted for large parts of the total nutrient intakes, whereas in the other animal categories most of the K and Mg in the feeds depended on external resources. Our findings also suggested that excessive Mg intake resulted in high Mg excretion and low use efficiency in dairy cattle and fattening pigs. At the regional level, the K and Mg amounts of manure produced and applied in the area (K: 339 and Mg: 143 t/year) exceeded those used as local feeds. Our results imply the animal production potentially increased the K and Mg loads in the regional agriculture system.     

太阳热处理对小白菜根肿病防治效果的研究

为探讨太阳热处理对小白菜根肿病的防治效果,以超级小黄白为供试材料,测定太阳热处理前后的土壤理化性质、根肿菌休眠孢子数量、土壤微生物多样性及发病率和病情指数,评价太阳热处理对小白菜根肿病的影响。研究表明:经太阳热处理后土壤0~10 cm处pH由4.96提高至5.60,根肿菌休眠孢子的浓度由1.09×10⁶ g^-1减少至5.74×10⁵ g^-1。变性梯度凝胶电泳(DGGE)结果证明,太阳热处理提高了土壤细菌微生物多样性,其中0~10 cm处和10~20 cm处土壤细菌微生物群落的香浓维纳指数分别由1.51、0.91提高到1.98、1.53,0~10 cm处根肿病的发病率由87.10%降低到49.12%,病情指数由45.24降低到16.96,防治效果明显。本研究为太阳热处理在实际农业生产中的应用及对根肿病的防治提供了理论基础。     

Estimation of nitrogen and phosphorus flows in livestock production in Dianchi Lake basin,China

We assessed the nitrogen (N) and phosphorus (P) flows in intensified livestock production systems by investigating nutrient budgets and cycling in the basin of Dianchi Lake, one of the most eutrophic lakes in China. We conducted field surveys based on feed samplings and interviews of livestock farmers. The N and P in local and external feeds, animal body retentions, animal products and excretions were calculated at the individual level for dairy cattle, fattening pigs, breeding sows, broilers and laying hens. The N and P flows in the total livestock production system in the area were estimated by multiplying the individual N and P budgets by the number of animals. For the dairy and fattening pig productions, N and P supplied from local crops or by‐products accounted for large parts of the inputs. For the other livestock categories, most of the N and P inputs depended on external resources. The N and P outputs through animal manure into the cropland were 287 and 66 kg/ha/year, respectively, which were higher than the N and P inputs into the livestock production systems from the cropland. The N and P loads from manure should be reduced for the establishment of sustainable agricultural production systems.