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This study was conducted to analyze the prevalence and quantitative loads of Salmonella spp. on pig farms in Chiang Mai, Lamphun, Thailand to assess loading levels before slaughtering. The serotype diversity, antimicrobial-resistance pattern and pulse-field type of Salmonella spp. were also characterized to assess the dynamic propagation of the pathogen. The Salmonella-positive prevalence was 246/805 (30.56%), and the quantitative loads varied from 1.48~4.04 Log10MPN/g, with a mean ± standard deviation of 2.11 ± 0.57. AMP/S/TE (ampicillin/streptomycin/tetracycline) was the highest frequency antimicrobial resistance pattern found in this study. In addition, Salmonella Rissen was the primary serotype in this region. PFGE results indicated the occurrence of infection by cross contamination among pig farms. Our study showed that pork is easily contaminated with this pathogen. Farm control programs must be based on strict biosecurity and hygienic measures, which could further reduce the contamination pressure at slaughterhouses or retail shops.  相似文献   
2.
The poorly integrated cane supply planning between mills and cane growers in the Northeast of Thailand generates an excess of cane supplies that exceeds the mills’ capacity during the peak of harvest season. Each grower individually determines his/her cultivation plan by selecting planting dates and cultivars based on one’s own preference without taking into account the individual mill’s capacity and other growers’ plans. This situation causes most sugarcane grown in this area to reach its mature stage at the same period. In this study, we propose a framework of cultivation planning to cope with the problem. The focus of the cultivation plan is a long-term plan to determine the cultivation time, the cultivar selection and the corresponding prospective harvesting time window for each field such that overall sugar production is optimized.The crop growth model and a mathematical model are employed for yield simulation and optimization task. The crop growth model enables decision-makers to visualize cane production of each individual field at different dates with different cultivars and allow decision-makers to apply the mathematical programming to cultivation planning. The suggested framework has the potential to increase sugar production by 23% when compared to the traditional method.  相似文献   
3.
Due to the pressure to become more competitive, feed mills coordinate closely with their suppliers and customers by forward purchasing raw materials and integrating with downstream units such as animal producers. To integrate downstream units and forward purchase raw materials, the mill must explore new paradigms for managing integrated information. The close relationship between customers, suppliers and the feed mill allows the feed manager to access information that was not previously available, such as the price of raw materials and the demand for feed products, which creates a more deterministic environment. In the present study, to exploit information from the integration of production units, an extended planning horizon was evaluated by developing a mathematical model and a heuristic algorithm for multiple period planning. The simulated results indicated that feed mills are likely to benefit from expanding the planning horizon. On average, the costs obtained from multiple-period planning were approximately 2.55% lower than those of single-period planning. Moreover, because recipe costs fluctuate dramatically, mills benefit from multiple-period planning by accounting for variations in recipe costs. However, the savings of multiple period planning are limited by other factors such as inventory holding costs and the warehouse inventory of the feed mill.  相似文献   
4.
Shrimps of all sizes are obtained by direct purchasing from independent farms then sorted and sold by size. Shrimp that has not been sold is kept in cold storage, a heavy burden for shrimp processors. In this paper, a mathematical model and a heuristic model based on the dynamic programming are developed to facilitate harvesting decisions for shrimp processors. The objective function of the proposed model is to minimize the cost related to by-size inventory. The effectiveness of the heuristic model is evaluated under a combination of scenarios with various parameters. The results demonstrate that the heuristic model is quite effective and practical in solving the problem.  相似文献   
5.
This study was conducted to determine the effects of mixtures of liquid brewer’s yeast (LBY) and cassava pulp (CVP) with rice straw (RS) on feed intake, digestibility, rumen fermentation, and growth of dairy heifers. Sixteen Holstein crossbred heifers (13.8?±?1.6 months old, 210?±?23 kg body weight (BW)) were randomly allocated to four feeding treatments with four replications, which were 0:0:100 (RS), 0:70:30 (0%LBY), 20:50:30 (20%LBY), and 50:20:30 (50%LBY), respectively, for LBY/CVP/RS on a fresh matter basis. The heifers were offered conventional concentrate at 1.5% initial body weight daily and fed the treatment diets ad libitum. Average daily gain and feed intake were not significantly different among the treatments. The heifers fed 50%LBY had the highest crude protein (CP) intake and DM, OM, and CP digestibility (P?<?0.05). The ruminal pH did not differ significantly among treatments, while NH3-N was the highest (P?<?0.05) in 50%LBY. Total volatile fatty acid (VFA) concentrations and the molar proportion of each VFA were not significantly different among the treatments. Blood urea nitrogen concentrations of 50%LBY were the highest among the treatments (P?<?0.05). The results indicated that 50%LBY improved CP digestibility.  相似文献   
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