This study was designed to devise a method by which the optimum combination of dietary energy and protein could be found that maximises the margin over feeding cost in an egg production enterprise. It was necessary to be able to predict feeding costs and revenue associated with the use of a wide range of feeds varying in protein and energy. To this end, two experiments were conducted using 256 Lohmann (128 White and 128 Brown) in the first, and 1296 Hy-line Brown laying birds in the second trial, that were 33 and 38 weeks old at the beginning of the two trials. Using the WinFeed 1.1 (1996) feed formulation programme, four basal (corner) feeds were formulated in both experiments, from which four protein and four energy contents (16 feeds) were produced in the first experiment, and six protein and three energy contents ( 18 feeds) were used in the second. Each feed was given to three replicates of 16 birds in the first trial, and to three replicates of 24 birds in the second. The trials each lasted ten weeks, and the data collected included food intake, change in body weight, egg weight and rate of laying. Using the results from these two experiments and from previously published research, the effects of dietary protein and energy on food intake were predicted independently, and these predictions were then used to determine the cost of feeding. Similarly, egg weight and rate of lay were predicted independently for changes in dietary protein and energy, from which the revenue could be calculated over the range of energy and protein contents. It is understood that a more integrated approach would be more accurate for this purpose, but such an approach was beyond the scope of this investigation. The use of contour plots based on regression analyses of the estimated income-minus-feeding cost on changes in dietary protein and energy enabled evaluations to be made of the effect on profitability of changes in egg price and maize price. And it was deduced that under conditions in which the maize price is high, maximum profitability is achieved with high energy and high protein content, irrespective of the price paid for eggs. When the maize price is reduced, the combination of protein and energy that yields the highest return over feed cost changes to low protein and low energy feeds. This change is defensible on the grounds that the price of high-density feeds does not change as much as that of low-density feeds when the maize price is lowered, whereas production, and hence returns, remains the same, hence the low density feeds yield higher returns under such circumstances. The method applied in this study appears to be a useful tool for decision-making by egg producers and nutritionists. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Apesar da evolução do consumo e produção e ovos no Brasil nos últimos anos, os investimentos em ambiência bem-estar são poucos, tornando a atividade vulnerável a variações climáticas. Esta tese teve por objetivo revisar o impacto do calor na produção de ovos, avaliar as respostas produtivas de mortalidade de poedeiras e de perda produtiva devido ao clima, usando dados medidos em estações meteorológicas. Os resultados e a revisão que fazem parte desta tese estão apresentados sob a forma artigos científicos. A revisão bibliográfica estuda a questão do bem-estar animal e o impacto das variações climáticas na produtividade de poedeiras. O segundo artigo avalia a influência das variáveis ambientais do mesmo dia e de dias anteriores à postura, sobre a produtividade de ovos. E o terceiro artigo classifica a ocorrência de mortalidade elevada de poedeiras em condições meteorológicas potencialmente desencadeadoras de estresse térmico. O banco de dados utilizado foi composto por dados de uma empresa de produção de ovos para consumo, incorporados aos dados de produção esperada obtidos de manuais de linhagens e aos dados de estações meteorológicas próximas às granjas. A análise dos dados foi com a técnica de mineração de dados, utilizando duas classes tanto para produtividade como para mortalidade. O nó raiz das árvores de classificação da produtividade e da mortalidade, reforça que a ocorrência de valores de ITU iguais ou acima a 23º C, desencadeia o estresse por calor, influenciando a produtividade e a mortalidade de poedeiras comerciais. Os dados meteorológicos de estações próximas e os registros zootécnicos de granjas de galinhas poedeiras comerciais apresentam padrões que permitiram desenvolver modelos compreensíveis e relevantes para estimar quedas na produção e a ocorrência de mortalidade elevada, causadas por eventos climáticos de calor. Aves poedeiras comerciais leves e semipesadas tiveram redução na produtividade com valores de ITU maiores que 23 ºC. Aves poedeiras alojadas em granjas com idade superior a 21 semanas apresentaram elevação da mortalidade quando ocorreu pelo menos uma hora com 23 ºC de ITU. / Despite the evolution of consumption and egg production in Brazil in recent years, investments in welfare and animal environment are few, making the activity vulnerable to climatic variations. This thesis aims review the heat impact in egg production, evaluate productive losses and laying mortality due heat stress, using data from meteorological stations. The results and the review that are part of this thesis are presented in scientific articles. The literature review discusses the issue of animal welfare and the impact of climatic variations on egg production and consumption. The second article evaluates the influence of environmental variables of the same day and days before the posture, on productivity. And the third article classifies the occurrence of high mortality of laying hens in weather conditions that could potentially trigger thermal stress. The database used consisted of data from an egg producing company, incorporated into the expected production data obtained from lineage manuals and data from meteorological stations near the farms. Data analysis was done using the data mining technique, using two classes for both productivity and mortality. The root node of the trees of productivity and mortality classification reinforces that the occurrence of Temperature Humidity Index (THI) values equal or above 23 ºC, triggers heat stress, influencing the productivity and mortality of commercial laying hens. The meteorological data from nearby stations and the producing data of commercial laying hens farms present patterns that allowed the development of understandable and relevant models to estimate falls in production and the occurrence of high mortality caused by climatic events of heat. Light and semi-heavy commercial laying hens had a reduction in productivity with THI values greater than 23º C. Layers housed on farms over 21 weeks showed increased mortality when it occurred for at least one hour with 23º C of THI.

Apesar da evolução do consumo e produção e ovos no Brasil nos últimos anos, os investimentos em ambiência bem-estar são poucos, tornando a atividade vulnerável a variações climáticas. Esta tese teve por objetivo revisar o impacto do calor na produção de ovos, avaliar as respostas produtivas de mortalidade de poedeiras e de perda produtiva devido ao clima, usando dados medidos em estações meteorológicas. Os resultados e a revisão que fazem parte desta tese estão apresentados sob a forma artigos científicos. A revisão bibliográfica estuda a questão do bem-estar animal e o impacto das variações climáticas na produtividade de poedeiras. O segundo artigo avalia a influência das variáveis ambientais do mesmo dia e de dias anteriores à postura, sobre a produtividade de ovos. E o terceiro artigo classifica a ocorrência de mortalidade elevada de poedeiras em condições meteorológicas potencialmente desencadeadoras de estresse térmico. O banco de dados utilizado foi composto por dados de uma empresa de produção de ovos para consumo, incorporados aos dados de produção esperada obtidos de manuais de linhagens e aos dados de estações meteorológicas próximas às granjas. A análise dos dados foi com a técnica de mineração de dados, utilizando duas classes tanto para produtividade como para mortalidade. O nó raiz das árvores de classificação da produtividade e da mortalidade, reforça que a ocorrência de valores de ITU iguais ou acima a 23º C, desencadeia o estresse por calor, influenciando a produtividade e a mortalidade de poedeiras comerciais. Os dados meteorológicos de estações próximas e os registros zootécnicos de granjas de galinhas poedeiras comerciais apresentam padrões que permitiram desenvolver modelos compreensíveis e relevantes para estimar quedas na produção e a ocorrência de mortalidade elevada, causadas por eventos climáticos de calor. Aves poedeiras comerciais leves e semipesadas tiveram redução na produtividade com valores de ITU maiores que 23 ºC. Aves poedeiras alojadas em granjas com idade superior a 21 semanas apresentaram elevação da mortalidade quando ocorreu pelo menos uma hora com 23 ºC de ITU. / Despite the evolution of consumption and egg production in Brazil in recent years, investments in welfare and animal environment are few, making the activity vulnerable to climatic variations. This thesis aims review the heat impact in egg production, evaluate productive losses and laying mortality due heat stress, using data from meteorological stations. The results and the review that are part of this thesis are presented in scientific articles. The literature review discusses the issue of animal welfare and the impact of climatic variations on egg production and consumption. The second article evaluates the influence of environmental variables of the same day and days before the posture, on productivity. And the third article classifies the occurrence of high mortality of laying hens in weather conditions that could potentially trigger thermal stress. The database used consisted of data from an egg producing company, incorporated into the expected production data obtained from lineage manuals and data from meteorological stations near the farms. Data analysis was done using the data mining technique, using two classes for both productivity and mortality. The root node of the trees of productivity and mortality classification reinforces that the occurrence of Temperature Humidity Index (THI) values equal or above 23 ºC, triggers heat stress, influencing the productivity and mortality of commercial laying hens. The meteorological data from nearby stations and the producing data of commercial laying hens farms present patterns that allowed the development of understandable and relevant models to estimate falls in production and the occurrence of high mortality caused by climatic events of heat. Light and semi-heavy commercial laying hens had a reduction in productivity with THI values greater than 23º C. Layers housed on farms over 21 weeks showed increased mortality when it occurred for at least one hour with 23º C of THI.

Text in English / The study was conducted in two different types of natural ventilated housing systems; one featured with conventional laying cages while other had free-range system features. The aim was to analyse productivity and economic benefit or loss of the Lohmann Brown Lite on different housing (Free-range system and Conventional cage system) with an evaluation of production cost. The total of 49 700 point of lay Lohmann Brown Lite layers pullets were placed in four natural ventilation free-range houses each consist of three rows of two tier conventional laying cages. The other 40 000 point of lay Lohmann Brown Lite layers pullets were place in four free-range houses each with placement of 10 000 chickens. The Cobb Douglas production model was used to determine the productivity of two different housing system by factoring the fixed cost and variable cost of the entire production process. The breakeven point tool was used to analyse the point where the total revenue equals the total variable and fixed expenses and the cost volume profit by measuring the profitability of each housing system (Nabil et al. 2014). The results of the study revealed different productivity between conventional cage system (82.94%) and the free-range system (77.46%). These results led to the acceptance of hypothesis 1 that “the production of Lohmann Brown Lite is the same when they are kept on the free-range system or conventional cage system. The capital investment and operation on conventional cage system showed breakeven at 43 months while free-range system showed breakeven at 60 months. The economic benefit analysis shows that the free-range system has cost benefit of R0.29 and conventional cage system has a cost benefit of R0.26. It means for every rand spent, farmer may get R0.29 Rand as profit for free-range system and every rand spent for conventional cage system can get R0.26 Rand. The economic benefit to farmer is greater on free-range system that lead to acceptance of hypothesis 2 that the economic benefit of egg production is greater on the free-range system compared to conventional cage system. Free-range housing system remain the best alternative to replace the conventional cage housing system. / Agriculture and  Animal Health / M.Sc. (Agriculture)

This study investigated the feasibility of small-scale poultry production to contribute to household food security in the Maphephetheni lowlands in KwaZulu-Natal. Forty households, selected by stratified random sampling (eight households per sub-ward) participated in a trial to assess the feasibility of egg and broiler production, from commercial lines, and the potential for generating income to improve household food security. The study established that participating households acquired the necessary skills through a training module offered, actively engaged in poultry production and marketing of the produce, and managed their funds well. Market demand for poultry products in the Maphephetheni lowlands was high from both local consumers and traders. Egg production profit was constrained as eggs were not sorted into sizes according to South African standards and local selling prices, but, contrary to commercial market practice, the eggs are graded ‘standard’ regardless of size. Both egg and broiler production are technically feasible in Maphephetheni lowlands, but broiler production is more economically viable than eggs and more highly desired by households. Households reported that poultry production could provide much needed income and reduce poverty and hunger in their community. Although household dietary diversity did not improve, income increased and was put into a savings account. Households borrowed and used this money for various needs, but not necessarily to supplement their diets. Commercial point-of-lay pullets and three-week old vaccinated broilers could be used in the Maphephetheni lowlands, but broilers were more commercially viable than point-of-lay pullets. It is recommended that broiler houses be established with the capacity for brooding each 500 day-old chicks which are sold (live) at six weeks. However, technical and financial support is required to maximise the benefits, increase household income, improve diets and reduce vulnerability to food insecurity. / This study investigated the feasibility of small-scale poultry production to contribute to / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.