トップページ - 横浜国立大学学術情報リポジトリ

全文

(1)The. Effect. IIatching. of. Chick,. of仙e. Size. Egg. Special. with. Result. in. Growth. Early. the. on. Reference. to仙e. Crossbred. the. by. Yuichi. Modern. broiler. an. view-point ･because. a. in the. a. the. QuINN,. 1931; there. However,. In that. the. exist. basis. could upon. Lbased. .growth. -reported. * **. object the. age,. the. and. economic. for them,. required. egg. the. of. was. production. of this large. the. being. (HAYS for. were. the. of. was. study. percentages. by. reported SANBORN, 1929; and. effect. et. all, 1956;. YAO,. Hampshires,･the. authors. of there from. hatched. a. JuLL. MoRRIS, egg. early. 1964)･. size. the. on. (HAZEL. and. 1961;. meat-type. 8. at. vanished. emphasized. that. estimated. from. utility. of. yot】-nger. tocompare. breed. to. age. ages. 10. weeks. SIE-. indicated. the. could. the. bring. largely. time, age･. On. selection. about. in且uenced. the. and. body. components. variance. not. de一 13%. the. of. therefore,. were. effect,. of. heritabilities. them,. of. have. maternal growth, 65% at hatching. chick. five weeks. weights. the. closely. weight. and TINDELL. approximately. authors. before. egg. 1952;. at.,. chicks BRUNSON. almost. which for. weight the. 70%. The. hatched.. were. are. rate. growth. 1966)･. on. that. effect of egg size on in the medium that size. high by. chick breed. previously.. Department. of. Agriculture. Department. of. Animal. 280. postnatal. et. New. trust. hardly. chick. in. the. origlnal. to. all, 1953;. et. the. chicks. because †､e氏ciency, the egg size. The. weight. the. of. growth. size. and. fact. this. in young. `analysis. be. should. egg. controversies. using. of. age,. of. of. to. RoBERTSON,. egg. advance. >､at. weight. several. and. of. effect. 乍CreaSed with 4 weeks. From. ability･. egg. they. which. time. report. previous. the. -the. of eggs. CLAYTON. 1962;. LGEL,. and. from. to the contributing 194=7; MARTIN. _periods LAMOREUX,. chicks. from 62 ranged 1950; KosIN WILEY,. workers. tan°. of. hatching. at. of. number. weight. weight. weight. ･of chick. between. characteristics. chicken. the. rule,. to. -related. hatching. the. correlation. genetic. laying. highegg. of. size. two. have. should. AKITA**. Tomiji. and. relatively. adequate. negative. ､▲observed As. mothers and. rate. growth. :rapid. SAEKI*. Genetics,. National. institute. of. Animal. Industry,. Cbiba.

(2) 18. Y.. SAEKI. Materials. Two FIS. their. (WC8. separately. were. through Cbick 16･0%. and ration. period.. starter. ration. crude. fed In. 73･0%. classiaed The effect computed. by. ∑x2). ∑y2. six. single. basket.. 68･0%. (C･P･). the. for. N･. Chicks. sexed. a. with. Brstfive. per. Chick-,. (T.. D.. nutrients. N.). broiler丘nishing:. weeks, for. C･P･. tester. chick. Space. digestive. total. and this′. individually. were. the approprlate. 17･0%. and. hens. mature. keeping. battery. the. data,. and following丘ve. the. egg. to. the. weeks･. sum. At. respectively.. the. e若g. by. same. and. Weight. the. body. the. body. weight. 70gp･. weight. was.. ((∑xy)2/. where the. and. regression. time,. above. and. ((∑xy)2/∑x2)/∑y2-r2,. squares. of. were. produced. of bi-weekly. variance. formula;. represent. maternal. 987 chicks were which 54-57, 58-61, 62-65, 66-69,. 50153,. weight. orlglnal. from. eggs. following. the. squares,. the. these. grades,. the. of. appraise. from. T･D･. the. of. into. the. acquired. Rocks and White (WR), broilers were for used. libitum.. ad. between. (WC). containing. protein. analyses. and. Cornishes. appropriating. a. in. test. containing. were. in. reared. the. Methods. for. eggs. hatched. and. weighed. AI(ITA. and. White. 8×WR♀♀). Hatching. experiment･. of. breeds,. parental. T.. and. of. total. coeaicient was. sum. correlation_. also. to,,.. estimated. effect.. ResⅦlts. E#ect of. egg. Average. egg. 64･6±5･1, in. Average different. sizes. No. hatching. Cro33breds. eggs. Particularly. White. of both. sexes. Cornishes,. higher. especially from rate. growth eggs. of. from. those. in. three. the. same. the. eggs. hatching. at. for. 8 'Ⅳeeks weight. of. groups with. size. weighing. White. of. 54g. all to. egg. both. the. the. the. egg. 73.8%. for.. The〉 40g. above. delayed. 62165. and. parental. 1). 66169g. purebreds, test. whole. at_. despite Fig.. 1 and. represented. weight. groups.. weighed. of 58161,. The. groups.. size. (Table. the. hatched. and. generally age. from. newly. Rocks. the. throughout. 73.7g. of in. time. among. above Cornishes. compared. weights. weights. eggs. White. as. egg. found. after. 10 weeks. at. hatched. chicks. Body. 72.2%. the. the. of l･. orlglnal. from. time. respectively.. Table. were. Wereゝ. hatching. at. those. and. PIS. their. and. chicks. 49.Og,. week. the. differences. of all the. the. period.. maximum. groups. of. example. various. to. weight. size,. in. given. proportion. egg. from. produced. the. are. (FAS) obtained a. weight An. other. every. obtained chicks The growth. time. large. showed. in. de丘nite. Rock. their. 1,819.2g,. of chick for 70.4%. averaged. White. of in. percentages. FIS.. weighed. Rocks The. respectively･. 45.5, 45.4, and. 1,779.5, and. weights. were. chicks. 66･5±4･6g,. and. breeds i,601.7,. were. chick grou)th u)ith age in White Cornishes, White. w･eights. 62･9±4･1,. respective. age. the. on. size. sizes. the of. weekly eggs. changes. is given. of weight in Fig. 2.. rankings. The. of. rankings. the. chicks. of. the. from_. Wbiteニ.

(3) Effect. Table. egg. 1.. wt.. wt.. g. g. WC 1盲￣…【￣1. WR(A) Fl. o. Chick. on. of. weights sizes. of. ∃. g. 2. 4. g. g. 39.3. 154.. 40.5. ∃ ユ,47.2 1 151.7. i. 56.7±0.4. 42.0. 60.3±1..0. 42. 3. 60.2±1.2. 43. 0. 60.4j=1.0. 44.7. 63.3±ユ‥0 63. 9±1..i. 64. 1.＋1..2. 44.2. 0. WC. White. Cornish. White. Rock. …. Ⅵ｢R. ‥･. Fl. females is,. and. those. of. size且uctuated. chicks 2nd-group. the. 7 weeks. of. in. their. declined. g. ーー喜 g. wks.. 10 g. 446. 7. 903. 3. 1.,363.. 435.i.. 854.. 1,312.6 1,136.7. 7. 5. 800. 0. 3. ユリ856. 7. I,738. 4 ユリ463. 3 1.,605. 0 3. 749. 5 866. 0 958. 6. 1,159.5 i.,320.. 1,369.7. 1,743.7 1,584.3. 3. 1.39. 8 1.60. 5 i.85. 4. 383. 465.. 7 518. 3. 75ユ..3 902. 3 961.4. 1.,1.59. 0 i.,357. 3. 1.39.i.. 387. 8 477. 2. 756. 923.. 1,157.3. 1. 524.4. 980. 6. !. 403･2. 1 47. 3. was. 8. 1,752.. i. 6 1. 1,796. 3 1,802.7. i,372.7. ユリ368.2. 1,397.. i.,598. 7 ユリ796.4 0 t∃ 1..839. 9 1,663.5. 499.1. 1.,876.. 3. 543.. 1,008,0. 1 1,442.6. age,. 6. 1 1,893.3. the. eggs. and. female. ones. the occupied from the eggs. highest. after. 4 to. from. the. the. groups. egg. expressed. parental. ranked after. ranking. 70g. above. breeds. above. eggs. below. galn. per. described both. including 70g. (Fig･ 2)･ Altbougb from. egg. White. age.. groups. weighing. 10 weeks the. of. both. the. that. weighing. 5 weeks. The. group. crossbred lst-ranking of the. with rate. time taken. chicks. in. changes. (62-65g). 3rd-group. hatching. throughout. in accordance growth. at. changes,. with. the. as. while. in. be intricate. to. seemed. males. that closely concerned chicks an It is interesting ages･ problem. ranking weight different phase. fotlnd. irregular. Rock. hatched. newly. (66-69g). from the obtained fastest the growth. Tbe. White. the. of. ranked. prominently. slight. 8. 壬72喜;≡ ⊆書7i冨;墓. 46.. accompanying. male. above. 6. -WC(66)×WR(♀♀). cornish. A. r. 426.. i.43･6 177.7 i.98. 0. 70′). Rock. from. (6＋?)･. eggs. 166. 9 190.3. 66′〉69. that. hatched. chicks. ≠. 岳. 19. Growth. 倍宝(A) ≡;7;喜…壬;至i喜喜;冒【信妄(A) 岩左冒:宝l壬儲:28 至宝;7?…喜;芸邑≡皇;g6 信妄(A). 62∼65. grew. egg. 56.6j=1.. 58′ー61.. 6. different. 倍妄(A) 倍宝(A). 54′〉57. to. the. 53.5±0.2. 50∼53. as. body. Average. aVe･. breed. Size. Egg. of. maintained. there 69g. sexes. appeared. those. chicks. size･ in. percentage. Week. reached. a. peak. declined increasing in most it abruptly 2 weeks breeds, at of age and with in growth at As usual, the FISalso the same age, while age. reacheda peak White on the former during the from Rocks kept higher than period values 3 to 10 weeks Growth in the FI from was rate smaller eggs Chicks of age. generally. superior. to. that. from. larger. ones･.

(4) 20. Y.. SAEKI. T.. and. AKITA. rg) 2000. (g) 58-61. ) ) ). WC. 66-69 ￣￣T￣￣58-61. WR㈱. ￣-L￣166-69. 1500. ￣￣‥-￣ー￣￣￣58-61 66-69. I--””￣￣L. ′∫′. /. WCxWR. ,d7;I/# ′. 二二三…二…三) NH. .. Jコ. .暫. ;. .A#f. /. 1000. ら｢⊃. ∈). /. /. ID. //9'J//. / :I,;I( ノ〃/メ. 500. :('1/. ･3;. O. i. 1. 2. 3. 諾. 4. 5. in. age. 6. 7. 8. 9. 10 wks.. weeks. 〔⇒. Fig.. 1･. Growth. curves. the. of. Egg. in. (S＋♀). different. same. sized. breeds. from. produced. eggs. groups.. weight(Rank.) 70-(9=‖ 66--69. (2). ● /一一. 1<一 62-65. (3). 58′-61. (4). ￣′.′. ヽ′. ･●-I. -. Ill. ･. -●. ---- ･-･- -. I. ￣ヽ.--..●. I. -＋. wcxwRノ♂ ヽ♀ 70･+9). (l). 66-69. 【2). 62-65. (3). ---∼--. -●----●--1十-I-●---∼. ヽ. ヽヽ. /( 58-6J. (4). 54-57. (5). ､■-__′′. 0. Fig.. 2.. Weekly the. ]. changes. different. 2. of groups. 3. 4. weight of. 5 ranking. egg. size. 6. of in. 7 the. 8 chicks. WCxWR(Fl)･. 9. hatched. I 0 yvKS.. from.

(5) Effect. Egg. of. Size. Chick. on. Growth. 21. (q) I. .tヽ. 40. I.I .1. 30. ;I:[･' .1. .I:. 【J]. 己. (9). E6 bD. ZZZ …68二…三) 書…86二66と) wc. ∼. ,.G. bD. 'S. 2. a. wR. 58･-61. ). WC. 匠:詔66-69. WR. I. ● ○●. ‡l●. ●●. ● ●. 0 ■. ● ､＼. ○ o--2. 4--6. 2-4. h. age. Fig.. 3.. FAS. their. Weight. Produced. the. 〃kS.. weeks. W￣hite. Cornisbes,. different. sizes. in. gains from. 8 -IO. 6∼e. Rocks. White of. eggs,. ranging. chicks. taken. and from. 58to69g.. Weight are. eggs. size. creased kept. during. White. the. white of. through. in The. estimated the. a. in. higher. PIS. the. orlglnal the. effect. These i.e.,. directly. the. regression. egg. weight. PIS. exhibited. the. with coefBcient rose. the. Of. larger. with. in. the. former. White. and at. the. were. age. 6-8. week. However,. (66-69g)･ the. in. that of. Cornishes. the丘nishing. increase. but. in. gain. weight. the. to. maximum disappeared. 6 weeks. ones. in-. all breeds. the. 6 weeks,. same. used. almost. the. after. in proportion gal血. to. the. breeds. breeds. the. except. from. changed. galnOfthechick. in. first. gains. eggs,. those. those. size. phenomena. (58-61g). three. from. manifested. egg. the. weight. the. among. of. through. especially period, the 66-69g egg size.. of. weight from. differences. the. than. FIS. the. the. whole. case. particularly. smaller. thereafter. and. The. phases,. rather. the. but. in. gains. the丘gure,. obscure.. from. were. in. conspicuotlS. strange. gala. weight. best. was. weight. age. of. of age.. was. taken. The. 3･. in the. 2 weeks. every. shown. 6 weeks,. Rocks. somewhat. period,. Fig･. 10 weeks. Cornishes. Rocks. on. As. the負rst. 8 to. the. till 6 weeks. plateau.. for. gain. in. seen. sharply a. during. gains. orlglnal period. egg. size. was. the. in lg. that of egg weight for the (b- ∑xy/∑x2) chick weight in breeds･ the age all advancing. maximum. gain. of. ll･7g. at. 10 weeks. of.

(6) 22. Y.. Contrary. age･ last. to. coeBicients betu)een. ln Table. a. showed. original. low. generally. value. the. at. this. thereafter egg. to. effect. advancing. with. The. age.. chicks 6 lots,. effect. the. of. weight,. chick. present on. Table. decreasing/. more. the. a. reported. effect. male). cor-. disappeared they were after maternal e庁ect, almost It is different New Hampshires of age. previously result with FIS fairly that the high even revealed at 10 weeks old correlations. size. 6 weeks. the. was. in 2 week-old correlation in the highest group of the. the. of. weight. high(＋0.8) significantly hatching weight at time and. chick. Rock. (White. egg. and 3 breeds, of. between. CoefBcient. weight. fell to十0.44. u)eight. results. found. was. egg. abruptly. chick. 2 representing. coefBcient. relation. in. Cornishes. this, the. AKITA. T.. and. period.. Correlation. at. SAEKI. the. 2. of. chick. large. A. study.. for. growth. Correlation. coe氏cients. egg. to. breed. weight. sex. egg. the. in. size longer. a. variance. of. o. 2. 1. 0.876**. 0. 309**. γ. i. (,2). egg. body. Fno･(rr2)岳 87. weight. (r2). weioght. F. 4. 0. 872**. (r2) Total. o.. γ. 0. 420**. 5. 0.. γ. o.. γ. 0. 444**. (γ2). Total. 0. 206*. 0. 835**≡. !592. 0. 384**. 0. 087. 0,236**;. 0.058. wks. i.0. -0.. 004. (0･ 000). r. o･122. き(o,o15). (0.120) HO,070). (0.004). o･176**. 0. 1.64**. HO･031). (0･027). o,l14**. 0.ユ.08*. o･249**j o･417**; 0,328**i (0･108). i. (0.062). 0. 059. (0･003). o･347**j o･265**i. (r2) i (0･697) ; (0.174). r. 0. 084. (0･043) ! (0.008). 0. 312**;. (0･577) ≡(0･ 147). ㍗. & mean. 760**!. 1. 5_竺･__?56)〉ぎ￣￣￣￣ド----I--￣￣￣￣. 9 27■. ?. 8. 007). (γ2) (0･78ユ). (0･ユ･97) (0･098) ≠(0･056) WR(A). r. and week.. !(0･0ユ.3) (0･. _. o1236*. r. 31 3. 6. other. ｡Z二喜……,*き｡Z:. _?_･ _?_1_'1_ j. 0. 349**. !. _ 884**′. weight,. every. 0. 1.15. 0,105. (0.757) ; (0･ユ･22). (r2). mean. 870**;. favorable. 0. 338**. (0･760) ( (0.177). 1.5;1.. &. in. 6. i(..751)≡(..095) (0･1･1･4). r. body. and. 6;4. WC. a. exert. may. period.. between. (r). PIS. the. i (0.0ユ3). (0･0ユ･2). l. γ. l. 穴. jユ.22. 1. 0.773**. 1I- o･. 0. 290**. ￣￣-1. 250**l. 0.ユ77*. 0.i.97*. 0. 202*. +. (γ2) (0. 597). (O1 084). (O1062). i (0.031). (0･039). (0･ 04ユ･). l. γ. Fl T. (WCxWR)i. 0.87ユ**. (γ2) (0･ 759). l. r-i恵a￣1 γ. F. 0. 828**. 244. (γ2). mean. *-P<.05. o. 359*.). ユ22. **-P<.01. (0･ 686). !. (0.ユ.29) 0. 325**. 0. 323**. 0. 288**. 0. 263**. (0･1･04). (0･ 083). (0.069). 0. 244**f. 0. 234**. (0･063) l (0･060). (0･055). (Z:喜…;,**3 o.妄ラ6;-*i. (0.1.06); (0.073). 1. 0. 251**. :.

(7) Effect. The. effect. were which hatching at. in. from. As. stated. 23:. Growth. the variances ofしOdy weights'to formula ((∑xy)2/∑x2)/∑y2-r12 were. the. 75･7%. in Cornishes,. above,. subseqnent. being. Chick. on. weights. egg. orlglnal. computed time,. FIS.. the. the. of. Size. Egg. of. in White. 69･7% γ2. 68･6%. and. declined. rapidly. value. higher-. Rocks,. beloⅦ･ 20%･-. Discussion. Tbe. present in egg. group. This. due. in. In. spite. size,. the. pared. :. ∇eekly. 1) to. chick. weight. the. the. on. growing the. that. by. reported In. and. the. the. Rocks. for. does. production breeders. cannot. not. help. kind. any. those. be. live. for. the body. of. or. sizes･. any. other during. growth. ill. occurring to. worthy. study. CornishesI. of. Rocks. White. and. of. various. weights. Leghorns. com--. following. (b). defects. of. egg. whole. of. ratios. from. it may. Otherwise, the. 2). chick growth, delay of chick. the. by. to. broiler. the. as-. coexist taking. with. that. means. growing. periody. egg. per. the. the. meat--. strains. of. White. to. conforming. 170 eggs to. performance laying. egg. Hampshires･, for. performance. high. that to. egg. improved. be. should in New. ability in some is no more than. mother. Assuming. all, 1964･. mother. laying. laying. broiler. the. broiler. high. average. the of. is, 56-58g. a. expect. the. autbors･. the. that. eggs,. from. obtained. is aThis size･ White Rocks. Cotnishes,. to. purebreds. the. that. chicks. throughout. proportion. the. by. production,. results. in in. results. to. for et. induced. faster. instance,. SAEI(I. to. size. the. changes. obtained on. as. coefBcient. intricate. chicks. egg. excellent. sized. appropriating. according. for. reported. medium. breeds,. the. Considering. with. up. it is difBcult. Naturally,. of. recommended. authors. for laying. of the. sexes,. the. large二. mostly. by. proved. regression. addition,. weights. more. Hampshires. The. type. from. point. chicks,-. delayed. Ⅶ･as. both. 3). were. them. is actually. of embryos･. (FIS). crossbreds. manifested this breed grew. New. male. al･, 19681. et. eggs. namely different. from. and. age. be. may. compared. SAEKI. the. larger. as. only. Cornishes. combined In. rate･. albumen. of. lowest. This. weight,. effect. stages. ratios. the. were. taken. to. it. period,. chicks. weight.. egg. growth. developmental. the. egg. slight. controlling. of. consisted. White. by. used.. according a. group. yielded. weight. original. suggest. factors. breeds weekly. ranking. eggs. of. the. of. growth. average. the. smallest Table l･. event･. eggs. two. the. weight. weight. the. that. the. in the. seen. as. growth. superior. represented. reason. hatching. of. Ⅶith. defects. to. it is unexpected. though. even. (50-53 g). size. is mainly. from. hatched. Rocks. White. that. showed. work. year,. the. meat. breeds･. some. ln. per. the. condition. e庁ect,. if the. of. the. their･. country.. Considering a. large. factors. including. between egg correlation di&cult breeds, more problems. negative. mon. these. scale.. the. number will. maternal egg. and arise. to. the. weight, broiler. as. PIS seen. production. pOSSeSS･. in. com-. on. a.

(8) 24. Y.. MERRITT ratio _If. (1968) be. would. breeders. mothers. a. traits. 二prOduction. and be. may. days. performances for the nickability. high. of. to. useful. solution. this. of. in. by. their. advancing. hybrid-type. of. AKITA. for the 63/147 selection induce a increase correlated. to. means. T.. and. that. reported. expected. take. SAEKI. body egg. broiler. the. using. both. weight. production.. meat. and. egg. problem.. Sllmmary The the. present. growth. large. study. of chicks. per the. test. in. were. crossbreds. weight,. i. e.,. at. percentage. of. chick. -found ￡oefBcients. The. FIS. but. to. were. the. egg. the formula. these. abruptly. effect. mostly. groups. and. for. sexed. Cor一. six. 66-69,. controlled. above. the. space. through. chicks. of. orlglnal. 10 weeks. at. at. to. the. egg. weight after. C.C.,. G.F.. G.A.. F.A.. the and. Exp.. B.L.. two. after the. of age.. weeks growth,. chick but. hatching. at. the. maternal in. effect. the. FIS. cited 1956.. GooDMAN,. body. and. W.F･. relation. and. Br.. year.. 良. SANBORN,i.929.. Bull.. Sciリ26,. Jut,L, M.A,. and. ten･week. RoBERTSON,. laying. Sta.. L･N･ in. A,. and. during _HAYS,. were. were. which. weight 70%. weig王It. Types. breast. and. angle. of in. gene. in. action. broilers･. Poultry. 524-532.. Sciリ35, 1CLAYTON,. of. correlation. age.. GoDFREY. inheritance. tbe. The. were. age.. hatching,. Literature BRUNSON,. 17% on. breeds. 0.35, and therein White correlations. of body. variances. Rocks,. about. the. broiler. the. to. time. for White. weight. to. However,. below. to. 6 weeks. of. egg. ((∑xy)2/∑x2)/∑y2-r2. of. at. and. hatching. 0.83 in all the. declined. 0.1.. of. at. 72.2%. aboやe. time. even. sexes. for Cornishes,. rapidly. decreased. the. vanishes. remain. age. level. weight. from. Thus,. of. the. both. coe丘cients. slgni丘cant. of. effect. estimated. iIAZEL,. in the. White. into. 62-65,. of the. group. involved. hatching. at. the. decreased. and. 血ay. breeds,. Classi丘ed. 58161,. batteries. each. 70A%. correlation. chick weight 2nd-week. in. these. effect,. 54-57,. The. weight. averaged. high. between. time,. hatched,. were. three. (FIS),. 50-53,. to. random. from Were. basket.. single. a. asslgned. Signi丘cantly. after Rocks. between. relationship. they. which. taken. eggs. their. egg original weight for FIS. 73.8%. and. from. eggs,. the. period.. The Lthe. of. hatching. and. hatched. and bird. Rocks,. the individual. on. size. incubation,. to. 皿ishes, White. 170g,. and. determine. to. conducted. breeds.. meat-type Prior. based. was. to. No.. Genetics Sciリ7,. 143-151‥. growtbin. Rbode. Rate. 259,. of. of. changes. lsland. in. traits. economic. Reds.. Mass.. Agr.. 302-321.. LAMOREUX, sexual. 1966. Poultry. maturity. 1947. and. Heritability, body. maternal in. weight. White. effects. and. Legborns.. nicking Poultry. 508-514.. J.P.. QuINN,. 1.931.. The. inheritance. of. body. weight. in. the. domestic.

(9) Effect. KosIN,. fowl.. ∫.Heredity,. I.L.,. H.. of. egg. MARTIN,. G.A.,. in. a. Y.,. SAEKI,. at. 1968.. Natl.. E. meat. 32,. 716-720･ for. estimates. Y･. KEDA,. growth. TANABE,. K･. and. Ⅴ･ Laying. Y.. AKITA,. Y･. TANABE,. of. these. from. eggs. TAMAKI,. N.. and. for. Anim.. response. WILEY,. e氏cient. ュnd. Bullリ19,. P.Bリ1962. D.. TINDELL,. and. and D.R.. performance. 1950. W.H., 29, T.S., lines. 1969.. selection 53-61‥ for. Selection MoRRIS,. cbickens･･. gain. weight. at. The. The. maternal the. on. and. for. of. weight. eight weeks 954-962. Sciリ41,. effects. of. egg. weight. the. interior. correlations. meat in. of. on. quali-▲. ⅤⅠⅠ小. Natl.. 1.. age.. New. among.. production.. broilers.. some.. of. weight. various. and. on. effect. chick. Short. Inst... term･,. broiler'. subsequent. 534-539.. in且uence in. traits･. Breeding-. meat-type. of. chickens. rapid. Poultry. 1964.. ibid., 43, The. Breeding. for. body. beritabilities.. hatchinggrowthrate. YAO,. ONISHI,. SuGIURA,ユ964･. breeds. meat･type and 5, 231-237.. ibidリ. characteristica.. Age. SIEGEL,. Leghorn. for. selection. and reproductive 190-1･991 ibidリ4了,. performance. traits. ties. 247-254-. 6, 33-40.. 1968･ and hatchingeggsize I, Effect of chickens. of 226-230. Sciリ5, Hampsbires. Japan. Poultry Weight SAITO,i.968. H. CIIIBA, H. and T.. of. influence'. 31,. Sci･,. E氏ciency. fowl.. type. meat. of. strain. production･ Ind. Bull.,. Anim.. 1953.. The. 1952･. Poultry. cbick･. BLOW,. ibid.,. ages.. the. of. W.L.. parameter. control. for Inst.. various. J.S. CARVF-R,. and. growth. and. Genetic. randombred K. FuJIOKA,. cbickens. early. GLAZENER,. growth. E.S.,. 25･. Growth. Chick. on. J. GuTIERREZ,. subsequent. E.W.. broiler. MERRITT,. on. Size. 22, 283-294.. ABPI.ANALP,. size. Egg. of. on. egg. the. fowl.. variations. in. Egg. the. on. weight 2.. weight-chick. pre･batcbing weight. and ratios･. post-I. ibid･,A. 595-604. 1961.. of. Genetics chicken.. ibid.,. the. 40, 1048-1059.. progenies. of. the. diallel. crosses. of. inbred-.

(10)