The environmental factors on the lamb growth, analytically studied with extra-seasonal-lambs I : Extra-seasonal-production of lambs by artificial light treatment

広島大学水畜産学部紀要 Volume 2 Issue 2 Page 365-374 published_at 1959-12-20
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Title ( eng )
The environmental factors on the lamb growth, analytically studied with extra-seasonal-lambs I : Extra-seasonal-production of lambs by artificial light treatment
Title ( jpn )
季節外生産羊を利用しためん羊発育に及ぼす環境要因の分析的研究I : 単日処理による仔めん羊の季節外生産
Creator
Mimura Ko
Asahida Yasushi
Source Title
広島大学水畜産学部紀要
Journal of the Faculty of Fisheries and Animal Husbandry
Volume 2
Issue 2
Start Page 365
End Page 374
Abstract
(l) Trials involving a total of 18 Japanese Corriedale ewes were conducted in an attempt to gain several lambs under artificial light treatment over three out-of-seasons.
(2) Artificial lighting and black-out treatments for controlling the breeding season of ewes were tried in a light-proof pen.
(3) The hours of exposure to light were allowed daily for an actual day light to keep a gradually increasing light rhythm until the total light length corresponded to summer solstice, and then it was changed over from increasing to decreasing light by artificial lighting and darkness. When the light length was corresponded to winter solstice the constant light length was kept up. In the second and third seasons, the rhythmical changes of light were designed to elapse more rapidly.
(4) All of ewes under light treatment came in oestrus for 40-50 days' intervals after the change-over from increasing to decreasing light. It may, therefore, be considered that there are some constant intervals in Corriedale ewes to come in oestrus under short day treatment. And it is of some interest to say that these intervals will be in accordance with natural intervals, if there may probably be a silent heat before onset of oestrus under normal condition.
(5) 13 out of the 16 oestrous ewes became pregnant as a result of induced mating after one cycle interval. Several of 14 lambs which were produced in the present experiments were born weak. It may be necessary for further investigations to set such questions at rest.
Descriptions
The authors wish to express grateful thanks to the Ministry of Education for grants in aid and to Mr. H. MORITA, Mr. K. MURAKAMI, Mr. T. HORIKAWA, Mr. K. HASEGAWA, Mr. T. MOTOTANI, Mr. M. MASUNISHI, and Mr. K. SHIMAKAWA for general assistance.
NDC
Animal husbandry [ 640 ]
Language
eng
Resource Type departmental bulletin paper
Publisher
広島大学水畜産学部
Date of Issued 1959-12-20
Publish Type Version of Record
Access Rights open access
Source Identifier
[ISSN] 0440-8756
[NCID] AN00213563