Effects of Environmental Temperature on Egg Production, Food Intake and Water Consumption in Laying White Leghorns : Ill. Effects of Humidity

白レグ産卵鶏24羽を用い，実験(I)は乾球温度30および32.5℃でRH60又は80%で，実験(II)は同じ鶏で25～32.5℃低湿条件で行ない，さらに以下の実験をとりまとめ，1971実験(A)25～35℃(既報)および同じ鶏で高湿で1971実験(B)と1970・実験25～35℃(既報)について，湿度が採食，飲水，卵かくにおよぼす影響を調査し，次の知見を得た.
1) 体重あたりの採食量は湿球温度の変化(RHの変化)に関係なく，ほぼ乾球温度により影響(高温で減少)をうけた.
2) 飲水量，卵重，卵かくの厚さも同様に乾球温度により影響をうけた.(高温で飲水量大，卵重・卵かくのあつさの低下)
3) 高温における体重減少は，鶏の体熱放散機構からみて湿度が関与しているかもしれない.

The present research work was performed in view of investigating the effects of humidity, under the several DBT and changes of WBT, on food intake, water consumption and egg shell quality in White Leghorns based on a series of experiments. Twenty-four laying hens were kept in a temperature controlled room under 30 and 32. 5℃ at 60 and/ or 80% RH during 3 weeks in Experiment I; and under 25, 30 and 35℃ at lower humidity in Exp. II.

For confirmation, previously reported 1970 Exp. (A) and more humid 1970 Exp. (B) (unpublished, 30 and 32. 5℃, 60-70% RH) and previously reported 1971 Exp. were compared to the present data. The results obtained were as follows.
1) Each food intake per 1 kg of body weight, irrespectively of wide change of WBT and controlled by DBT, was surprisingly constant especially under higher temperature ranges.
2) Water consumption, egg weight and egg shell thickness also seemed to be controlled mainly by DBT.
3) The body weight may have a tendency to be affected by humidity in relation to evaporative system as to the thermo-regulation in chickens.