首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4篇
  免费   0篇
  2篇
畜牧兽医   2篇
  2014年   1篇
  2012年   1篇
  2011年   2篇
排序方式: 共有4条查询结果,搜索用时 0 毫秒
1
1.
Supplementation of vitamin E has indications for improving cattle health, performance, and retail characteristics when included in grain-based diets. This experiment was conducted to determine performance and carcass characteristics of steers fed diets containing wet distillers grains with solubles (WDGS) and supplemented with vitamin E. Steers of mixed Bos indicus and Bos taurus breeding (n = 199; BW = 363 ± 32 kg) were blocked by BW and assigned to 1 of 4 supplemental vitamin E (VITE) treatments [0 (control), 125, 250, and 500 IU·steer(-1)·d(-1)], which were fed for the last 97 d of the feeding period. Two blocks were on feed 129 d, and 3 blocks were fed for 150 d. Steers were fed a dry-rolled corn-based finishing diet with 35% WDGS (DM basis). Individual BW were measured initially, the initial day of vitamin E supplementation, and the day of slaughter. Carcass weights were collected at slaughter, and carcass data were collected after a 36-h chill. Body weight and ADG were not affected by VITE (P ≥ 0.34). There was a tendency for a linear (P = 0.08) increase in carcass-adjusted BW with increasing VITE. Use of carcass-adjusted final BW resulted in a linear increase (P = 0.04) in ADG with increasing VITE. Pre-vitamin E and vitamin E feeding period DMI were not affected (P ≥ 0.24) by VITE, but there was a tendency (P = 0.08) for a linear increase in overall DMI with increasing VITE. No difference (P ≥ 0.29) occurred in G:F measures using BW gains, but G:F using carcass-adjusted BW gains resulted in a trend (P = 0.11) for G:F to increase linearly with increasing VITE. Hot carcass weights tended (P = 0.08) to increase linearly with increasing dietary vitamin E. Vitamin E supplementation resulted in no effects (P ≥ 0.13) on measured carcass characteristics. Calculated yield grades (YG) were also not affected (P ≥ 0.37). However, the distribution of calculated YG resulted in a quadratic effect (P = 0.02) for YG 3 with the control and 500 VITE being greater than the 2 intermediate amounts. However, the percentage of carcasses grading YG 3 or less were not affected by vitamin E supplementation (P = 0.64). No differences were observed in the distribution of quality grades based on marbling scores (P ≥ 0.57). Data from this study suggest that vitamin E supplemented above basal requirements during the last 97 d of the feeding period in finishing diets containing 35% WDGS results in slight to no effect on animal performance or carcass characteristics.  相似文献   
2.

Purpose  

In situ contaminated sediment remediation through the addition of activated carbon has been proven to be an effective remediation technique. An amendment delivery system was developed to accurately place and inject a powdered activated carbon slurry. The system was set up to deliver a series of discrete injections over a rectangular grid with the objective to deliver 3% carbon (C) by dry weight to an inundated saturated sediment at a maximum sediment depth of 30 cm.  相似文献   
3.
This study investigated bovine coronavirus (BCV) in both beef calves direct from the ranch and commingled, mixed-source calves obtained from an auction market. The level of BCV-neutralizing antibodies found in the calves varied among ranches in 2 different studies in a retained-ownership program (ROP), from the ranch to the feedlot. Calves with low levels of BCV-neutralizing antibodies (16 or less) were more likely to be treated for bovine respiratory disease (BRD) than those with higher titers. In 3 studies of commingled, mixed-source calves, BCV was recovered from calves at entry to the feedlot and the infections were cleared by day 8. The BCV was identified in lung samples [bronchoalveolar lavage (BAL) collection] as well as in nasal swabs. Calves with low levels of BCV-neutralizing antibodies at entry were most likely to be shedding BCV. Bovine coronavirus was isolated from both healthy and sick calves, but not from sick calves after 4 d arrival at the feedlot. Bovine coronavirus (BCV) should be considered along with other bovine respiratory viruses in the diagnosis of etiologies in bovine respiratory disease, especially for animals that become sick shortly after arrival. If approved vaccines are developed, it would be best to carry out vaccination programs before calves are weaned, giving them sufficient time to gain active immunity before commingling with other cattle.  相似文献   
4.

Purpose

Sediment contamination in US waterways is an expensive and complicated issue, and as acceptance of nontraditional sediment remediation strategies broadens, novel and efficient methods to assess and monitor the bioavailability of hydrophobic organic contaminants (HOCs) in contaminated sediments will play an important role.

Materials and methods

In this project, solid phase microextraction (SPME) fibers inside perforated steel tubes were used as in situ passive samplers to measure polycyclic aromatic hydrocarbon (PAH) concentrations in sediment before and after treatment with activated carbon (AC). Two modes of waterjet amendment injection were used to apply the AC. In the first treatment, a single 2-min injection was shot into the center of a test vessel, and in the second treatment, multiple 7-s injections in a grid were placed in sediment.

Results and discussion

In the single injection, no treatment was observed 5 cm away from the injection, while at 2.5 cm, >90 % decrease of PAH pore water concentration was observed, indicating a similar bioavailability decrease. In the multiple injection experiment, >90 % PAH pore water level reductions were observed throughout the test vessel. Highly contaminated and less contaminated sediments were mixed with 0–5 % AC by weight to develop AC treatment curves. Over 99 % reduction in PAH pore water concentrations and bioavailability was observed in the less contaminated sediment at 3 % AC, while 99 % reduction was never reached even at 5 % AC addition in the highly contaminated sediment. Different treatment curves were observed for the different contaminated sediments. In situ equilibration times were 120, 215, and 250 h for phenanthrene, pyrene, and benzo(a)anthracene, respectively.

Conclusions

The results show that in situ SPME is a viable method to observe AC treatment and evaluate reductions in pore water concentrations and bioavailability.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号