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畜舍溫度降到幾度肉豬會開始生長遲緩?

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總帖子數排名︰4

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發表於 2012-1-6 13:19:11 | 顯示全部樓層
這議題已經在很早以前討論很多了,只舉一個被引用比較多的文獻之摘要,要討論事理之
前請先讀書,而且讀書要會整理,千萬不要斷章取義,記得引用別人的東西必須將人名
、出處、文章名稱寫出來,否則不是不清不楚就是盜取著作權。
環境及飼養管理狀況不同會有不同的thermal balance溫區:
The assessment of thermal environment in relation to pig production.
L.E. Mount, Livestock Production Science, Volume 2, Issue 4, December 1975, Pages 381-392
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Abstract
The thermal environment comprises factors which influence an animal's heat exchange through the channels of evaporation, radiation, convection and conduction. The air temperature is often used by itself as an assessment of the thermal environment, but air temperature by itself is inadequate for this purpose unless conditions are standardized with air and mean radiant temperatures equal to each other, free convection, and an insulated floor. Farming environments are not standardized, but climatic investigations allow an equivalent standardized environmental temperature (ESET) to be calculated for a given situation.

Information on energy retention and heat loss in the pig has been derived from experiments under standardized conditions. ESET can be used to transfer the results of these experiments to pig farming conditions, and to determine for different types of housing the air temperatures equivalent to the effective critical temperatures found under standardized conditions.

Experimental results can then be used to estimate the production losses which occur when ESET falls below the critical temperature, and the decision can be taken on increasing feed or improving heating or nsulation. For pigs in gorups in the body weight range 20–50 kg, the calculated air temperatures for maximum productivity range from 14°C in an insulated house free from draughts to 22°C in an uninsulated house with draughts in winter. Below these temperatures the animals' heat losses increase by approximately 4 kJ/°C per kg per day. For a feed with 1 g = 12 kJ metabolizable energy, the increased heat loss leads to an increased feed requirement of 0.3 g/°C per kg per day for maintaining maximum production.

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