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Masters Degrees (Animal and Poultry Science)

Permanent URI for this collectionhttps://hdl.handle.net/10413/6571

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Browsing Masters Degrees (Animal and Poultry Science) by Author "Bokretsion, Hagos Teclezghi."

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    Nutritional means of overcoming heat stress in laying hens and broilers.
    (2003) Bokretsion, Hagos Teclezghi.; Gous, Robert Mervyn.
    The relationship existing between the broiler and the laying hen, the methods applied for estimating the effective energy using linear coefficients to five measurable components of interactions and their diet used in adjusting ME for heat increment of feeding, the environment in which they live, the physiological, metabolic, behavioural, and the productive changes that occur when birds are exposed to heat stress, were studied. Nutrition and temperature were of particular interest. Each different aspect studied was found to have an influence on the final performance of the broiler and the laying hen. Two major experiments were conducted. The objective of the first experiment was to determine if performance can be improved during hot weather by reducing the heat increment of the feed. Two EE: ME ratios were used, the low ratio being based on the least - cost feed and the high ratio being the maximum possible with the available raw materials, and three ND's were used to determine whether there was an interaction between the ME content of the diet and the EE:ME ratio. 360, 46-week old Hy-Line Brown layers were housed for ten weeks and each of these 2 x 3 feeds was replicated four times using 15 hens per replication (three cages of five hens per cage), making a random allocation of 60 birds per feeding treatment. Treatment means were calculated for the last seven weeks of the trial. Egg prices (c/egg), income generated and profit, under normal, 15% increase and 15% decrease for all egg grades were calculated. It was found that neither the EE nor the ME contents of the feeds had significant effects on ROL, EW, EO, ADG, or ME intake, though there were some variations in the response of these variables. Both the EE and the ME of the diet had strong significant effect (EE at P