Thesis (M.Sc) (Agriculture) --University of Limpopo,2009. / The study was conducted to determine the effect of dietary energy level and tanniniferous Acacia karroo leaf meal level of supplementation at finisher stage on performance and carcass characteristics of male and female Ross 308 broiler chickens. Three hundred and sixty, 21-day old male and female broiler chickens were assigned to twelve treatments with three replications of ten birds in a 2 (sex) x 3 (dietary energy level) x 3 (tanniniferous Acacia karroo leaf meal level) factorial, complete randomized design. Supplementation with Acacia karroo leaf meal had no effect on diet intake, digestibility and live weight of broiler chickens. However, supplementation with 9 and 12 g of Acacia karroo leaf meal per kg DM feed reduced fat pad weights in male broiler chickens by 26 and 29 percentage points, respectively. Similarly, supplementation with 9 and 12 g of Acacia karroo leaf meal per kg DM feed reduced fat pad weights in female chickens by 26 percentage points. These reductions were achieved without any significant reduction in feed intake and digestibility. However, the physiological explanation for this effect is not clear and it, thus, merits further investigation. / National Research Foundation.

This project researched the effects of pullet-phase feed restriction methodology or management and hen-phase diet fortification on female broiler breeder BW and carcass trait uniformity as well as on performance of the broiler offspring. Feed treatments had a significant effect on female BW and carcass trait uniformity at 22 wk of age, with sorting and scatter treatments having the highest uniformity estimates, compared to limited daily, skip-a-day and fibre-diluted programs. Feed and premix treatments did not affect traits after 22 wk of age as individual caging at 22 wk of age unified female BW uniformity across all treatments. Feed treatments did not affect the uniformity of age at sexual maturity, first egg characteristics or production parameters. Premix treatment resulted in decreased shell uniformity and increased uniformity of one of the production parameters, total egg mass. Feed treatments may have a greater effect on female broiler breeder efficiency than previously suggested. / Animal Science

Inclusion body hepatitis (IBH) has been occurring as an economically important, emerging disease of broiler chickens in several countries. Historically, IBH has been identified as a secondary disease, often associated with common immunosuppressive diseases. However, few studies have identified IBH as a primary disease with no apparent association with immunosuppressive diseases. The objectives of this study were to develop an animal model of IBH in commercial broilers, to demonstrate vertical transmission of fowl adenoviruses (FAdVs) in broiler breeders and to control IBH in broilers by vaccinating their parents with an inactivated FAdV vaccine. In order to develop an animal model of IBH in commercial broilers, fourteen-day old broilers were inoculated intramuscularly with 1x104 1x107 CCID50 of either FAdV x11a-like virus, two strains of FAdV-8a (FAdV-8a strain TR-59 and FAdV-8a strain T8-A) or FAdV-11strain 1047. Four days following FAdV inoculation, 5% - 15% mortality was observed and dead birds showed histologic lesions of hemorrhagic necrotizing hepatitis. This animal model reproduced the clinical disease, and pathological lesions of IBH that have been described in commercial broilers. In order to demonstrate vertical transmission of the FAdV, 35-week-old broiler breeders were inoculated with 1x106 CCID50 of either FAdV x11a-like virus, FAdV-8a strain TR-59, FAdV-8a strain T8-A or FAdV-11 strain 1047. Eggs from infected breeders were collected and hatched seven days post-inoculation. Clinical signs or mortality were not observed in parents; however broiler progeny derived from broiler breeders inoculated with FAdV-8a strain T8-A had 30% IBH mortality by seven days of age. The hexon gene loop 1 sequence of the virus isolated from affected broiler progeny showed 100% identity to FAdV-8a strain T8-A. In order to demonstrate protection of broilers against IBH by vaccination of their parents, four groups of broiler breeders were vaccinated with either FAdV-8a strain T8-A (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion, or FAdV x11a-like virus (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion at the age of 12 and 15 weeks. The control group was inoculated with 20% oil-in-water emulsion. Broiler progeny were challenged with FAdV-8a strain T8-A to study the immunoprotective effect of the vaccine. Although, survival of broilers following FAdV-8a strain T8-A challenge was not significantly different among vaccinated and non-vaccinated groups (P>0.05), immunoprotective effect was enhanced by the increase dose of FAdV antigens (P>0.05). Further studies are necessary to improve the vaccine efficacy to protect broilers against IBH.<p> In conclusion, the results of this study support the hypothesis that IBH in broilers in Canada is a vertically-transmitted primary disease with no known immunosuppressive involvement. The results also demonstrated that inactivated antigens of FAdV are able to partially protect broilers against IBH by vaccinating their parents. Further studies with different formulations, and priming the immune system of broiler breeders with live FAdV prior to vaccination with inactivated FAdV vaccines are necessary to improve the efficacy of inactivated IBH vaccine.

A series of experiments were conducted to examine the effect of chemical composition of the diet on intestinal <i>Clostridium perfringens</i> populations and necrotic enteritis (NE) in broiler chickens. In the first experiment, birds were fed high concentrations of dietary protein (fish meal or soy protein concentrate) and soluble fiber (guar gum). Clinical NE was not observed, however, there was a high level of <i>C. perfringen</i> colonization especially in guar gum fed birds. The next set of experiments examined the effect of various levels of DL-Met or MHA-FA on <i>C. perfringen</i> and other intestinal microbes. These experiments demonstrated a significant reduction (P < 0.05) in <i>C. perfringen</i> growth with methionine supplementation in ileum and cecum. The results suggest that both DL-Met and MHA-FA may reduce intestinal populations of <i>C. perfringen</i> in broiler chickens when used in high concentrations. The next three experiments were conducted to examine the effect of dietary glycine levels on gut <i>C. perfringen</i> populations, α-toxin production and NE lesion scores. Majority of birds showed clinical signs of disease with 4.16-8.33% mortality. There was a direct correlation between intestinal <i>C. perfringen</i> populations, NE lesions scores and mortality with dietary glycine level. However, due to the use of gelatin as the dietary source of glycine in these experiments, the diets also contained high proline levels which confounded our results. The last study was conducted to establish a direct causative relationship between dietary glycine concentration and <i>C. perfringen</i> growth and/or NE in broiler chickens using encapsulated amino acids. Birds fed diets containing high levels of encapsulated glycine had higher NE lesion scores than those fed encapsulated proline or no encapsulated amino acids, thus demonstrating a direct effect of glycine on intestinal <i>C. perfringen</i> growth. It is concluded that amino acid composition of dietary protein is an important determinant of intestinal microbial growth, particularly <i>C. perfringen</i>, and could affect incidence of NE in broiler chickens.

The harsh winter conditions on the Canadian prairies impose special challenges in providing acceptable environmental conditions for broiler chickens during transportation. A research program was developed aiming to improve the transport conditions for broilers. As part of the research program, a research project was developed to design and construct an experimental trailer equipped with active ventilation and heating, to characterize the performance of the experimental trailer in field tests under Canadian Prairie winter conditions, to develop, calibrate and validate CFD models used for simulating the environmental conditions found inside the experimental trailer, and to utilize one of the CFD models to predict the performance of the experimental trailer when subjected to different operational conditions. This dissertation consists of six chapters. The first introductory chapter reviews economical, logistical and legislative aspects surrounding the poultry transport industry. This chapter also includes a discussion of important parameters for the design of an experimental transport system, a review of fundamental concepts of the Computational Fluid Dynamics (CFD) modeling method, and why CFD was chosen as a tool to complement the experimental work in this project. The second chapter reviews the designs of commercial poultry transport equipment and how they inspired the design of an actively heated and ventilated experimental vehicle. The setup of the experimental trailer was also discussed in detail. The third chapter reviews the experimental protocol used to evaluate the performance of the experimental trailer. The performance of this experimental trailer was evaluated in a series of field tests conducted under commercial loading operations, in winter conditions on the Canadian Prairies. It was found that the average load temperature varied from 7.1 to 15.6°C in the nine sts of data. The system was able to maintain an environment above 1°C. As for the humidity level inside the trailer, the majority of sensors had representative relative humidity (RH*) values between 10 and 40%, with the rest having RH* values below saturation. The fourth chapter reviews the development, calibration and validation of the 3-D CFD models developed to simulate the environmental conditions inside the experimental trailer. A total of three CFD models were developed to simulate the three different ventilation regimes encountered in field tests. Sensitivity studies revealed that inlet velocities, heat and moisture production had a great impact on the results obtained from the CFD models. The levels of porosity investigated did not play a significant role. The standard error of estimate was selected as a statistical measure to evaluate the accuracy of the CFD models against experimental data. For temperature data, its standard error of estimate varied from 3.2 to 7.3°C. For humidity ratio, its standard error of estimate varied from 1.7 to 5.0 g of water vapour per kg of dry air. The CFD models were able to recreate the temperature trends as observed from experimental data. It was concluded that these CFD models have adequate accuracy to be used as a design tool for comparative studies. The fifth chapter investigates the use of the 1-fan CFD model to study several scenarios. Three cases were investigated, based on conditions which may be encountered by the poultry transport industry. The first case examined the effects of vehicle travel speed and ambient temperature. The second case looked at the effects of bird size, loading density and ambient temperature. The last case studied the effects of side tarp insulation and ambient temperature. For the range of values examined, results from the simulations concluded that ambient temperature, bird sizes, loading density and side tarp insulation value were important factors to consider in the design of an actively ventilated poultry transport vehicle. The last chapter of this dissertation summarizes the main findings in this research project, discussed future work and presented final conclusions. Overall, this research project answered two key questions in the poultry transport research program. Firstly, the experimental work proved that the concept of active ventilation and heating is a promising option to improve the transport conditions for broiler chickens during cold ambient conditions. Secondly, the CFD work demonstrated that CFD modeling is a valuable tool for designing the next generation of actively ventilated poultry transport vehicle.

A series of experiments were conducted to examine the effect of chemical composition of the diet on intestinal <i>Clostridium perfringens</i> populations and necrotic enteritis (NE) in broiler chickens. In the first experiment, birds were fed high concentrations of dietary protein (fish meal or soy protein concentrate) and soluble fiber (guar gum). Clinical NE was not observed, however, there was a high level of <i>C. perfringen</i> colonization especially in guar gum fed birds. The next set of experiments examined the effect of various levels of DL-Met or MHA-FA on <i>C. perfringen</i> and other intestinal microbes. These experiments demonstrated a significant reduction (P < 0.05) in <i>C. perfringen</i> growth with methionine supplementation in ileum and cecum. The results suggest that both DL-Met and MHA-FA may reduce intestinal populations of <i>C. perfringen</i> in broiler chickens when used in high concentrations. The next three experiments were conducted to examine the effect of dietary glycine levels on gut <i>C. perfringen</i> populations, α-toxin production and NE lesion scores. Majority of birds showed clinical signs of disease with 4.16-8.33% mortality. There was a direct correlation between intestinal <i>C. perfringen</i> populations, NE lesions scores and mortality with dietary glycine level. However, due to the use of gelatin as the dietary source of glycine in these experiments, the diets also contained high proline levels which confounded our results. The last study was conducted to establish a direct causative relationship between dietary glycine concentration and <i>C. perfringen</i> growth and/or NE in broiler chickens using encapsulated amino acids. Birds fed diets containing high levels of encapsulated glycine had higher NE lesion scores than those fed encapsulated proline or no encapsulated amino acids, thus demonstrating a direct effect of glycine on intestinal <i>C. perfringen</i> growth. It is concluded that amino acid composition of dietary protein is an important determinant of intestinal microbial growth, particularly <i>C. perfringen</i>, and could affect incidence of NE in broiler chickens.

Inclusion body hepatitis (IBH) has been occurring as an economically important, emerging disease of broiler chickens in several countries. Historically, IBH has been identified as a secondary disease, often associated with common immunosuppressive diseases. However, few studies have identified IBH as a primary disease with no apparent association with immunosuppressive diseases. The objectives of this study were to develop an animal model of IBH in commercial broilers, to demonstrate vertical transmission of fowl adenoviruses (FAdVs) in broiler breeders and to control IBH in broilers by vaccinating their parents with an inactivated FAdV vaccine. In order to develop an animal model of IBH in commercial broilers, fourteen-day old broilers were inoculated intramuscularly with 1x104 1x107 CCID50 of either FAdV x11a-like virus, two strains of FAdV-8a (FAdV-8a strain TR-59 and FAdV-8a strain T8-A) or FAdV-11strain 1047. Four days following FAdV inoculation, 5% - 15% mortality was observed and dead birds showed histologic lesions of hemorrhagic necrotizing hepatitis. This animal model reproduced the clinical disease, and pathological lesions of IBH that have been described in commercial broilers. In order to demonstrate vertical transmission of the FAdV, 35-week-old broiler breeders were inoculated with 1x106 CCID50 of either FAdV x11a-like virus, FAdV-8a strain TR-59, FAdV-8a strain T8-A or FAdV-11 strain 1047. Eggs from infected breeders were collected and hatched seven days post-inoculation. Clinical signs or mortality were not observed in parents; however broiler progeny derived from broiler breeders inoculated with FAdV-8a strain T8-A had 30% IBH mortality by seven days of age. The hexon gene loop 1 sequence of the virus isolated from affected broiler progeny showed 100% identity to FAdV-8a strain T8-A. In order to demonstrate protection of broilers against IBH by vaccination of their parents, four groups of broiler breeders were vaccinated with either FAdV-8a strain T8-A (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion, or FAdV x11a-like virus (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion at the age of 12 and 15 weeks. The control group was inoculated with 20% oil-in-water emulsion. Broiler progeny were challenged with FAdV-8a strain T8-A to study the immunoprotective effect of the vaccine. Although, survival of broilers following FAdV-8a strain T8-A challenge was not significantly different among vaccinated and non-vaccinated groups (P>0.05), immunoprotective effect was enhanced by the increase dose of FAdV antigens (P>0.05). Further studies are necessary to improve the vaccine efficacy to protect broilers against IBH.<p> In conclusion, the results of this study support the hypothesis that IBH in broilers in Canada is a vertically-transmitted primary disease with no known immunosuppressive involvement. The results also demonstrated that inactivated antigens of FAdV are able to partially protect broilers against IBH by vaccinating their parents. Further studies with different formulations, and priming the immune system of broiler breeders with live FAdV prior to vaccination with inactivated FAdV vaccines are necessary to improve the efficacy of inactivated IBH vaccine.

Two experiments were performed to evaluate effects of amprolium administration at specific times and concentrations in replacement broiler breeders of three genetic lines vaccinated against coccidiosis. Effects on performance parameters including body weight and flock uniformity, and post-vaccination oocyst cycling patterns were evaluated in addition to development of immunity following clinical Eimeria challenge according to gross and microscopic lesion scoring, post-challenge body weight gain (BWG), and total oocyst output. Experiment one was conducted on fresh pine shavings while experiment two was conducted on used litter remaining in treatment pens from the first trial. No significant differences were seen among treatment groups with regard to body weight in either trial. Increased magnitude of oocyst shedding was observed in trial one, Line A with the group receiving amprolium on day 10. Trends in the data indicated increased uniformity in Line A related to amprolium administration following day 21. The group in Line A receiving amprolium at day 10 showed a significantly lower degree of total oocyst output following challenge than the other medicated groups. The group receiving amprolium on day 10 in Line B showed significant reduction in post-vaccination oocyst shedding following treatment in both trials while all shedding was delayed in trial two when compared to the first trial. Effects on uniformity in Line B pullets varied between trials with trends indicating it being advantageous when used litter was a factor. Higher post-challenge BWG was observed in Line B pullets administered the low concentration at day 16 than the controls. Reductions in gross lesion development were seen in Line B pullets in both trials. Line C pullets receiving the highest concentration of amprolium at day 16 showed significantly less uniformity in trial one while the controls appeared to perform better than all medicated groups in trial two. All medicated groups in Line C exhibited delayed and increased magnitudes of oocyst shedding in trial two. These data indicate that the effects of amprolium on performance and immunity development are variable according to genetic strain and indicated that administration may be influenced by litter condition.

The transaction of agricultural products, which take place in the local farmers¡¦ market, has a variety of modes. According to Oliver. E Williamson (1991), the characteristics of transactions differ from incentives intensity, administrative control, and performance attributes. Based upon the foregoing, agricultural transaction modes in the local farmers¡¦ market distinctions into three kinds: (1) market mode (2) hybrid mode, and (3) hierarchy mode. The purpose of this study is attempting to abstract the crucial dimension of agricultural transactions for organizing some transactions this way and other transactions another. The overall objectives of this study can be said to be threefold: (1) To investigate and collect literatures about the agricultural transaction modes which are presently most popular in Taiwan. (2) To identify and distinguish these transactions into market mode, hybrid mode, and hierarchy mode as suggested by Williamson. (3) As an exploratory study, to suggest uncertainty as the crucial dimension of agricultural transactions alternatives, to demonstrate why and how uncertainty rule on the selection decision. The results from this study suggest that: (1) When the uncertainty of agricultural transactions is high, hierarchy mode appears to be feasible relatively. (2) When the uncertainty is low, market mode appears to be feasible relatively. (3) When the uncertainty is in an intermediate situation, hybrid mode appears to be feasible relatively. A case study of the broiler contracts of the Charoen Pokphand Enterprise (Taiwan) Co. shows that the relationship between feasible contract mode and uncertainty of transaction is consistent with theoretical expectation.

The environmental impacts of broiler production have recently gained considerable public attention due to concerns regarding the amount of ammonia (NH3) released into the atmosphere from poultry facilities. Sound scientific data are needed to accurately estimate the production of manure waste products and gaseous emissions. This research project was undertaken to quantify nitrogen (N) loss through air emissions from a broiler grow-out facility over 18 consecutive flocks using the mass balance method. Measurement of litter and caked litter (cake) mass at the end of each flock allowed for the calculation of litter and cake production rates for broilers reared on recycled rice hull litter. Nutrient (nitrogen, phosphorus, and potassium) content of all litter materials was also measured. Broilers were reared in a research facility under simulated commercial conditions. All input materials (birds, feed, and litter) used in this study were obtained directly from a commercial broiler integrator to assure applicability to the broiler industry. The litter management technique of ??top-dressing?? was also investigated to determine its effects on N emissions and litter and cake production rates. Nitrogen emissions, litter and cake production rates, and nutrient density of litter materials were found to vary significantly between flocks reared at different times of the year. Nitrogen emissions were significantly greater for summer flocks than winter flocks. Average N loss over all 18 flocks was 11.07 g N/kg of marketed broiler (g N/kg). Nitrogen partitioning as a percentage of inputs averaged 15.29, 6.84, 55.52, 1.27, and 21.08% for litter, caked litter, broiler carcasses, mortalities and nitrogen loss, respectively, over all 18 flocks. Litter and cake production was lower in the summer compared to winter. Average litter, cake, and all litter (litter + cake) production was 153.3, 74.8, and 228.2 g of dry litter material/kg of marketed broiler. Litter and cake phosphorus and potassium content was elevated during summer flocks, while litter material N content decreased in summer flocks. Therefore, season of the year is an important factor that scientists and broiler producers must take into account when performing measurements and calculations, sampling litter materials and air emissions, and developing nutrient management plans.