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解析的研究 : III. 発育および成長に及ぼす季節の影響

第1報,第2報において短日処理法および短日処理・ホルモン処理併用法により,合計27頭の子羊を季節外に生産したことを報告した.これらのうち21頭を常法により1年間(雌),6カ月間(雄)飼育し,その発育・成長および皮膚面積の発育を測定した,この結果を試験期間中に行なった正常羊の試験結果と併せ検討することにより,極めて明瞭に子羊の発育および成長に及ぼす季節の影響を解析することができたので報告する. 1. 生後3月令までの早期発育においては,正常羊と季節外生産羊との間に発育パターンに差違はみられなかった。このことから子羊の早期発育においては,内因的要因,母乳(主として同品種・系統では個体的要因に属しまた在胎中の母羊の栄養と関係する)その他の要因が外部環境より強力に作用すること,そしてこの時期がBRODY(1945)のいわゆるaccelerating-phaseと関連することを暗示している. 2. 三村(1956)の提唱した発育における屈析転向点としての3月令の意義は,秋季生産羊では4月令に延長されていたが,3月令以後春季環境にあったためと理解された. 3. 増体重および体長その他の成長において,3乃至4月令以後はその季節環境によりそれぞれプラス,マイナスの影響をみることができた.特に春季はプラス,夏季次いで冬季はマイナスに作用していた.体高比成長により検討した結果は体型にも影響することが知られた. 4. 皮膚面積増大率は発育における傾向と似ているが,より拡大して示される. 5. 季節外生産羊を産業的に生産できるなら,秋季生産羊が本試験の結果からみて,最も有利な発育・成長をとげるであろうことは興味ある知見と思われる.In order to determine how the environmental factors would affect the growth and development of lambs and to consider whether the growth pattern as described by MIMURA (1956) would be the same or different for lambs produced in normal season and one produced outside the normal season, twenty-one lambs were selected and reared among twenty-seven lambs which had been produced outside the normal season reported by MIMURA (1959, 1964) with eight lambs produced normally. They were reared during twelve months by female and during six months by male. The growth in live weight and the development in linear measurements investigated along with the growing of lambs, and the skin area on the part which was tattooed on the mid-side of lambs by the method reported by BURNS (1935) and MIMURA (1956) was also measured and the growth investigated. After this the lambs were classified into five groups; spring lambs, early summer lambs, summer lambs, autumn lambs and winter lambs according to their lambing seasons, and the data were compared each other. The results are as follows. 1. Although there are remarkably growth- differences after the the third month, a straight line shows until the lambs grow up to the third month, not only spring lambs but in other season lambs with the exception of autumn lambs. Autumn lambs grow up straight forward until the forth month. 2. The growth and development of lambs after about the 3rd month shows a considerably higher rate under spring condition, and a lower rate under summer condition followed by early autumn and winter conditions. 3. The results, therefore, indicate that the general pattern of growth and development suggested by MIMURA (1956) and the present experiments coincide, but that seasonal effects considerably affect the growth and development of lambs after the early stage. The remarkable decrease of growth rate, for example, in early summer lambs and summer lambs from the 4th to the 9th months against the clear increases from the 9th to the 12th months are pointed out. The seasons of summer and early autumn in the west districts of Japan are characterized as hot and dry. The growth and development of lambs are suppressed not only by climatic effects, but mainly by nutritional fall in feeding under these seasons. Lambs in Japan are also under-feeding in winter. 4. It is very interesting to observe that the general pattern of growth in early stages was not affected by lambing seasons, probably due to unknown endogenous factors, milk supply and others would overcome the environmental factors. Concerning the exception with autumn lambs from the 3rd month to the 4th month, it must be considered that when the lambs after the 3rd month are under spring condition the decrease of growth rate will be relieved. Then it will be correct to say that the growth will slow down to about the third month or the fourth month, if one want to discuss the point of inflection of growth on the lambs produced all over a year. 5. There was a significant correlation between the expansion ratio of skin area on the part tattooed and the growth in live weight, although the expansion ratio changed during the growing of lambs on a larger scale than that of the growth. 6. From the investigation of specific growth rate, under summer condition suppressing influences were shown in body length, rump length and rump width of winter lambs, but under spring condition advantageous influences were shown in those of autumn lambs as compared with that of lambs produced under normal season. 7. It is very interesting to observe that from the present results autumn lambs will be most advantageous commercially if the lambs could be produced under treatment.A part of the present report was summarized on the Proc. 9th International Congress of Animal Production, Edinburgh 1966

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

(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.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

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解析的研究 : IV 羊毛の成長と環境要因の影響

21頭の季節外生産羊と8頭の正常羊とを1957年～1963年発育試験し，生後1カ年(雌)，半カ年(雄)における子羊発育のパターンとこれに及ぼす季節の影響については前報に報告した.これと同時に実施した羊毛の成長とこれに及ぼす環境要因の影響に関する成果を本報で報告する. 1. 右mid-sideに1cm角に入墨した皮膚面より刈取った洗上げ羊毛重量の変化をみると，いずれも生後3～4月間に最高を示した.また春季に急増し，秋・冬季に減少の傾向のみられたことも興味深い.羊毛生産量は特に皮膚面積，長さと太さおよび，繊維数の函数と認められるが，子羊の発育初期においては，密度は当然減少するが，その他は全て増加の相(BRODYのself-accelarating phase)にあると考えられ，冬季生産羊の羊毛成長の変化はこのことを明瞭に示している. 2. 向上部位に成長した繊維数は全て3月令までに急速に増加し，以降そのレベルを維持するか増加したが，初夏生産羊では6月令以降すなわち冬～春季にかけ急減した. 3. 単位皮膚面積当り繊維数は，三村(1956)と同様減次減少するが，冬季生産羊では1月令に生時より大となった.羊毛密度は皮膚面積増大率と繊維数増加の両面から検討を要するであろう. 4. 繊維の太さの変化は，一般に3，4月令まで増大，4～6月令に細くなる傾向が認められた.LYNEら(1970)は，暑さは太さを減じるが寒さは太さを減じないと報告している.結果は秋～冬季に繊維の太さを減じる傾向が認められた.わが国西南暖地の冬季の寒さはきびしくないから，この事実は短日と栄養状態の低下に起因することを暗示している.It is not easy to show in full details the changes in wool production during the growing of lambs, mainly because the period of the year in which ewes will be lambing is mostly restricted to spring, consequently it will be difficult to separate seasonal rhythm from the original pattern of wool growth. In order to solve the problem the authors took twenty-seven lambs produced outside the normal lambing season from 1957 to 1960. And these twenty-one lambs together with eight lambs produced under normal condition were reared from birth to the twelfth month for female and from birth to sixth month for male, during the years 1957-1963 in order to investigate analytically the growth pattern and environmental effects. In sequence to the previous paper the authors report here now on wool growth and seasonal effects during the growing of lambs. Rapid increasing rates of number of fibre follicles on surface skin were observed within birth to the 3rd month in spring lambs, summer lambs and winter lambs; within birth to the 4th month in autumn lambs; and within the 4th to the 6th months in early -summer lambs. It was recognized that the most rapidly increasing periods were under early spring and autumn conditions. Wool density in winter lambs increased from birth to the 1st month differing from tendencies in other groups and the fact which Mimura has reported the progressive decreasing along the growing of lambs. On the variation, in general, of average fibre diameter increasing size from birth to the 3rd or the 4th months and declining tendencies from the 4th month to the 6th month were noticed. Especially poor sizes were remarkable in early-summer lambs within the 4th to the 6th months under autumn condition and in winter lambs within the 9th to the 12th months under winter condition. Therefore, the authors suggest that decline in fibre diameter may be attributed to day-shortness and poor nutrition rather than cold temperature under autumn and winter condition. It is very important to suggest that all components affecting wool production are increasing phases, in exception with wool density, during early stage after birth responsing to the rapid growth and development of lambs. In all groups the highest clean wool production per unit area occurred within the 3rd to the 4th months. Although the highest production in autumn lambs was synthetically attributed to the high growth rates in skin expansion, fibre diameter and fibre length within the ages, those in other groups might be attributed not only to one or two components which could be interaction of various components upon each other

鶏の幼雛期における採食行動について

鶏の採食行動は，自らの生理的条件のほか，照明時間および照度・飼料の形状や質・飼槽の大小・つつきの順位・社会的促進などによって大きく影響を受けることは知られている.しかし幼雛については必ずしも明らかにされていない.そこで，1群3羽の白色レグホーン種雄雛を用いて，餌つけ後2日(3日齢)から4週齢まで採食行動その他を検討した.雛は1日10時間(7:00 a.m.-5:00 p.m.)照明を与え，この間に自由採食させた.各週齢において連続2日間，1羽ごとの採食行動を30秒間隔で観察し，併せて飼料消費量を記録した. 1) 採食に費した時聞を，10時間の百分率でみると3日齢33%，4日齢42%で10日齢以降では50～60%であった.すなわち，餌つけ後ほぼ1週間に，採食に費す時聞は急激に増えて，その後3週間はほぼ一定となる.しかし採食速度(毎分採食量，g)は週齢につれて明らかに増えることが認められた. 2) 雛は，日齢に関係なく，点灯直後と消灯直前に最も活発な採食活動を行ない，文献の成績と一致した.しかし採食速度は週齢につれて午後に増大する傾向が認められた. 3) 2週齢以降において，採食活動の少ない雛の方が体重が大きかった.つつきの順位との関連があるのかもしれない.1. A group of 3 chicks were reared from 0 to 4 weeks of age in a brooder with food available ad libitum and their eating behavior during 10-hour days was observed. 2. Between 10 and 32 days of age chicks used 50-60% of a 10-hour day eating, while those at 3 and 4 days of age did use only 33% and 42%, respectively. The daily mean rate of eating, expressed as gram food per minute, increased with the progress of age in weeks. 3. The diurnal rhythm in the eating activity agreed with the previous reports. The food intake followed an overall pattern similar to their respective eating activities. 4. The older the chicks, the higher the rate of eating attained in the late afternoon. 5. After 2 weeks of age, the heavier the chicks, the lesser the time spent for eating

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II : 単日処理とホルモン処理併用法による子羊の季節外生産

　第1報において筆者らは，非繁殖期のコリデーノレ種雌羊を短日処理すると，長日から短日に変化してからほぼ40~50 日で人工的に発育を誘起できること，しかし第1回の発情では多くの場合妊娠しないこと，しばしば弱い子羊を生産することなどを報告した. 　短日処理によるめん羊の人工発情誘起法は，長期間を要する，管理に手数を要するなどの問題を有するが，反面最近数多く報告されているホノレモン処理法では，高価な薬品を相当量使用する他，その効果が比較的確実でない欠点が指摘される. 　筆者らは，両方法の併用法，すなわち強度の短日処理1週間(以後ホルモン処理終了まで同一日照時間維持)―黄体ホノレモン25mg/ 日x3~5 筋注-2 日後P.M.S. 750 i. u 筋注法の効果を試験した.またこの場合短日処理は，厚い黒頭巾を雌羊の頭に被せ，明るい羊舎内に放置する簡便法によった. 　1959~1961 ，6回に亘り21 頭を試験したが，発情と認められたもの19 頭(90%) ，妊娠―分娩，卵巣所見―黄体・グラーフ卵胞の存在により確実に発情と認められたものは17 頭， 81%に達した.また第6回試験では併用法による4頭をホルモン処理法による3頭と比較したところ，確実に発情したもの前者100% に対し，後者は33%であった. 　黄体ホルモン処理日数を3日に短縮しでも5日間の処理となんら差異を認めなかった. 　強度の短日処理により，下垂体機能の亢進乃至反応閥値の低下など，本併用法による人工発情誘起のメカニズムについても論議した. 　なお処理羊はP.M.S. 筋注後2日目に最も多く発情し， GORDON (1958) の報告と一致した.Following decreasing daylight treatment for 7 days, twenty four anoestrous ewes of Japanese Corriedale were injected with P.M.S. 750 i. u. after 3-5 injections of progesterone 25mg daily. The ewes in pretreatment of light were hooded with black thick-cloth, and were under control hours of daylight. This combined treatment was studied over three years 1959-1961, and the incidence of oestrus, presence of corpora lutea, and the state of follicular development was studied. Total 13 lambs were produced by nine of twenty-one ewes treated with the method, and average percentage of lamb-production per ewe was 1.44. The presence of corpora lutea and Graafian follicle was observed cytologically in 8 of I 0 ewes when their ovaries were examined at slaughter time. Seventeen of twenty-one ewes were induced oestrus and the percentage is about 81%. In the sixth trial, three ewes were under progesterone-P.M.S. treatment alone, and only one cytologically was observed in fertile. The percentage is 33%. Therefore, the hypothesis may be probably explained that the light treatment prior to hormone administration will reduce the threshold in pituitary activity to induce the ovarian activity to much lower level. There is no difference between the method of three days injection daily and the method of five days injection. Thus the method combined the pretreatment of decreasing daylight by a black hood with progesterone 25mg x 3 and P.M.S. 750 i. u. may be considered of practical application. The highest response was observed two days after the time of P.M.S. injection, followed by next day, and this is agreed with GoRDON's result.The authors wish to express grateful thanks to the Ministry of Education for grants in aid and to Mr. M. YosHIOKA, Mr. T. KIMURA, Mr. N. FUJIMOTO, Mr. K. SHIMAKAWA and Mr. K. KoMATSU for the general assistance.　本報の一部は「三村・岡本他.肉緬羊の研究.輿文社，東京， 1961」 および昭和34年度， 35 年度文部省科学研究費による研究報告集録農学編(II) .肉緬羊造成に関する試験(代表者.三村耕)にそれぞれ速報している