No description available.

Feed withdrawal is commonly used by commercial egg producers to induce molt and stimulate multiple egg-laying cycles in their flocks. However, the practice can compromise the welfare of the birds by elevating stress, suppressing the immune response and causing abnormal behavior. An alternate molt diet was examined using alfalfa diets, and a series of experiments were conducted to evaluate the physiological, immunological and behavioral responses of laying hens fed these diets. We assessed the changes in the levels of blood plasma metabolites after hens were challenged with 106 colony forming units of Salmonella Enteritidis (SE). Hens fed alfalfa diets displayed similar (P ≥ 0.05) levels of cholesterol, glucose, and total protein when compared to full-fed hens. Reduced levels (P ≤ 0.05) of triglycerides were observed in the alfalfa fed and feed withdrawal hens when compared to the full-fed hens. The immune responses of SE challenged laying hens fed alfalfa diets showed similar (P ≥ 0.05) heterophil to lymphocyte ratios (H: L) to full-fed hens whereas the feed withdrawal hens displayed elevated (P ≤ 0.05) H: L ratios. The feed withdrawal hens displayed reduced (P ≤ 0.05) levels of serum IgY early in the trial when compared to the alfalfa and full-fed hens. The alfalfa fed hens displayed lower levels of acid α glycol protein than the feed withdrawal hens and higher levels than the full-fed early during the trial but returned to levels that were similar (P ≥ 0.05) to the full-fed hens. The hens fed alfalfa diets displayed elevated non-nutritive pecking behavior early in the trial however, this behavior declined to levels similar (P ≥ 0.05) to the full-fed hens by the end of the trial. No differences in aggressive behavior were observed between the alfalfa fed hens and the full-fed hens. Hafnium chloride did not effectively mark the alfalfa diet; however, it can be used to track the passage of corn-soy layer ration. This research suggests that the application of alfalfa as an alternative molt diet can be effective in reducing potentially harmful effects which are usually associated with feed withdrawal.

Feed withdrawal is commonly used by commercial egg producers to induce molt and stimulate multiple egg-laying cycles in their flocks. However, the practice can compromise the welfare of the birds by elevating stress, suppressing the immune response and causing abnormal behavior. An alternate molt diet was examined using alfalfa diets, and a series of experiments were conducted to evaluate the physiological, immunological and behavioral responses of laying hens fed these diets. We assessed the changes in the levels of blood plasma metabolites after hens were challenged with 106 colony forming units of Salmonella Enteritidis (SE). Hens fed alfalfa diets displayed similar (P ≥ 0.05) levels of cholesterol, glucose, and total protein when compared to full-fed hens. Reduced levels (P ≤ 0.05) of triglycerides were observed in the alfalfa fed and feed withdrawal hens when compared to the full-fed hens. The immune responses of SE challenged laying hens fed alfalfa diets showed similar (P ≥ 0.05) heterophil to lymphocyte ratios (H: L) to full-fed hens whereas the feed withdrawal hens displayed elevated (P ≤ 0.05) H: L ratios. The feed withdrawal hens displayed reduced (P ≤ 0.05) levels of serum IgY early in the trial when compared to the alfalfa and full-fed hens. The alfalfa fed hens displayed lower levels of acid α glycol protein than the feed withdrawal hens and higher levels than the full-fed early during the trial but returned to levels that were similar (P ≥ 0.05) to the full-fed hens. The hens fed alfalfa diets displayed elevated non-nutritive pecking behavior early in the trial however, this behavior declined to levels similar (P ≥ 0.05) to the full-fed hens by the end of the trial. No differences in aggressive behavior were observed between the alfalfa fed hens and the full-fed hens. Hafnium chloride did not effectively mark the alfalfa diet; however, it can be used to track the passage of corn-soy layer ration. This research suggests that the application of alfalfa as an alternative molt diet can be effective in reducing potentially harmful effects which are usually associated with feed withdrawal.

No description available.

Induced molting is process used by commercial producers to extend the reproductive life of a laying hen. Typically, producers deprive hens of feed for a period of 7-14 days while reducing the amount of light exposure to the hens. This allows for regression of the reproductive tract and for a second cycle of egg production to occur. However, induced molting by feed deprivation has been shown to increase the hen's risk of becoming infected with pathogenic bacteria, such as Salmonella. This increased risk could mean an increase in contaminated eggs or egg products, which causes concerns for public health. This combined with increasing pressure on egg producers from animal welfare organizations has prompted the investigation of diets that would provide available energy for the hens, while still inducing a molt that is economically advantageous to producers. Alfalfa, provided in meal or pelleted form, provides only 1/2 the metabolizable energy and 1/4 of the calcium required of a laying hen that is reproductively active. Due to the decrease in nutrients, alfalfa was investigated as an alternative to feed deprivation. Studies were conducted to assess egg quality, egg production, consumer acceptance, and hen physiology.

Induced molting is process used by commercial producers to extend the reproductive life of a laying hen. Typically, producers deprive hens of feed for a period of 7-14 days while reducing the amount of light exposure to the hens. This allows for regression of the reproductive tract and for a second cycle of egg production to occur. However, induced molting by feed deprivation has been shown to increase the hen's risk of becoming infected with pathogenic bacteria, such as Salmonella. This increased risk could mean an increase in contaminated eggs or egg products, which causes concerns for public health. This combined with increasing pressure on egg producers from animal welfare organizations has prompted the investigation of diets that would provide available energy for the hens, while still inducing a molt that is economically advantageous to producers. Alfalfa, provided in meal or pelleted form, provides only 1/2 the metabolizable energy and 1/4 of the calcium required of a laying hen that is reproductively active. Due to the decrease in nutrients, alfalfa was investigated as an alternative to feed deprivation. Studies were conducted to assess egg quality, egg production, consumer acceptance, and hen physiology.

There is increasing interest in developing methods to detect and identify Salmonella, to eliminate or reduce the risk of contamination of shell eggs, and to retain the economic advantages of induced molting without increasing the risk of Salmonella enteritidis infection. S. enteritidis and S. typhimurium are the most common serotypes among 2449 known serotypes of the Salmonella, and are the causes of most egg- related foodborne salmonellosis in humans in the U. S. These two species are also responsible for environmental contamination and the incidence of infections. Therefore, this study was conducted in three phases consisting of ten in vivo and in vitro experiments. This study investigated the effects of zinc on Salmonella growth and survivability in poultry environments, and its ability to induce a molt in single comb white leghorn hens. In part, the antibacterial properties of zinc may reduce environmental contamination in a poultry house by interrupting airborne routes. The first phase involved detecting airborne bacteria by aerosol sampling methods, and then screening any Salmonella mutant (s) that survived desiccation by transposon footprinting. The second phase examined, in vitro, the addition of zinc on the growth kinetics of Salmonella under aerobic or anaerobic conditions, the effects of combinating zinc and acidic conditions on the growth kinetics of Salmonella in vitro under aerobic or anaerobic conditions, and the effects of zinc amended feed on the survival of a dry inoculum of Salmonella. The third phase investigated the ability of zinc propionate, as an alternative salt form of zinc, to induce molt in laying hens, the influence of zinc acetate and zinc propionate on gastrointestinal tract fermentation, and susceptibility of laying hens to S. enteritidis during an induced molt, and the comparison of digestive microbial crop and cecal communities among molted hens fed by either zinc acetate or zinc propionate amended molting diets with hens undergoing feed withdrawal or full fed nonmolted hens using molecular-based denaturing gradient gel electrophoresis.

Salmonellosis affects an estimated 1.4 million people a year with a great majority of cases never being reported. Salmonella Enteritidis (SE) can be found in a variety of foods including poultry meat and eggs. Susceptibility of SE colonization is increased by molting. Induced molting is used in the poultry industry to rejuvenate the hen??s reproductive tract and increase post molt egg quality and production. The most common molting method is complete feed withdrawal. Recent animal welfare pressures have encouraged the industry to seek alternatives to feed withdrawal with one alternative being feeding a high fiber diet like alfalfa. Alfalfa is high in protein, but low in energy which is desirable for a molt diet. Alfalfa??s fermentation properties have been thought to be an inhibitor in pathogen colonization during molting. Including a prebiotic such as fructooligosaccharide (FOS) in the molt diet is thought to further decrease colonization while benefiting the indigenous microflora. Laying hens were molted using alfalfa combined with different ratios of layer ration in an in vivo experiment. The hens responded comparably to the alfalfa molt dietsas they did to feed withdrawal as far as post-molt production parameters were concerned, thus showing that alfalfa was a viable alternative molt diet. Two in vitro studies were designed to evaluate the fermentation properties of alfalfa and layer ration combined with the prebiotic FOS and their abilities to inhibit Salmonella growth. Each treatment was combined with diluted cecal contents and allowed to ferment. The results showed that the most fermentation occurred when alfalfa was the substrate and was slightly increased with the addition of FOS. In addition, combining FOS with alfalfa inhibited Salmonella growth. To integrate these results, an in vivo study was preformed using an alfalfa/layer ration diet from the previous in vivo study with FOS. Volatile fatty acids and lactic acid measurements were made to evaluate fermentation while Salmonella colonization was measured in pertinent organs and in fecal shedding. The results of this study further substantiate alfalfa as a molt diet and conclude that the addition of FOS does, while not statistically significant, further inhibit Salmonella colonization.

The present dissertation describes some of the ground movement problems associated with tunnelling in soft ground. A possible response of pipelines to such ground movements is also studied in the context of a case history of pipes lying parallel to a tunnel centre line. Analyses of tunnel excavation with and without lining installation, and of the pipe behaviour, have been performed by means of the finite element method. Four examples of analysis and their results are presented, with the main characteristics related the each being highlighted. Field observations of ground movements caused by tunnelling in soil have been gathered together and added to those presented by Peck (1969) and Attewell (1977) in order to attempt to define empirical relations that could describe a geometric form of settlement profile and to predict its magnitude. A three-dimensional finite element program has been written in order to carry out the style of analysis that two-dimensional models cannot accommodate. The isoparametric hexahedral rectangular element has been used in view of its facility in programming and discretising the medium of interest. The computer program has been developed to allow for different loading conditions and calculations to be carried out using linear material behaviour only. Features which have been considered in the tunnel-ground-pipes analyses include simulation of incremental construction. Because it was clearly impractical to model the entire system of interest by means of a single finite element mesh, an alternative analytical-numerical hybrid technique is described.

No description available.