Nihon Chikusan Gakkaiho
Online ISSN : 1880-8255
Print ISSN : 1346-907X
ISSN-L : 1880-8255
Breeding Chickens for Meat Production
I. Growth and Feed Conversion in Pure Breeds and Their F1 Chikens
Yuichi SAEKIYuichi TANABEToshimatsu KATSURAGIKentaro HIMENO
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JOURNAL FREE ACCESS

1962 Volume 33 Issue 3 Pages 272-278

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Abstract

Experiments were carried out with chicks hatched 14 times during the period of 1960-1961. Six pure breeds, White Cornish of the Vantress line (CV) and of the Mt. Hope line (CM), White Rock (WR), New Hampshire (NH), Barred Plymouth Rock (BP), White Leghorn(WL), and Nagoya (NG), and their F1 chickens, totaling 16, were used.
1. The average body weights of both sexes at hatching of NH, WR, BP, CM, WL, and NG were 43, 42, 39, 38, 38, and 27g, respectively. CM and WR grew faster than the other breeds after one week of age. A significant breed difference in growth was observed at 4 weeks of age and thereafter. The average body weights of both sexes at hatching in F1 birds were 43g in NG×NH, 42g in BP×NH, 41g in CV×NH, and 40g in CV×WR. At one week of age, CV×WR was the heaviest, CV×NH the second heaviest, and WR×NH the third heaviest.
2. The average body weights of both sexes at 10 weeks of age in pure breeds were 1, 635g in CM, 1, 474g in WR, 1, 129g in NH, 975g in BP, 948g in WL, and 739g in NG. The body weight of CV males at 10 weeks of age was 1, 817g. The body weights of crossbreds showed intermediate values between the parents, e. g., 1, 577g in CV×WR, 1, 571g in CV×NH, 1, 368g in WR×NH, 1, 304g in BP×NH, and 1, 272g in CV×WL all at 10 weeks of age.
3. No significant difference in the variation of body weight was observed between the pure breeds and their F1 groups. The coefficient of variation in percentage was about 10%.
4. A significant sex difference in body weight was observed not at hatching but at 4 weeks of age, Males were 201g heavier than females at 10 weeks of age.
5. The growth rate expressed in percentage gain per week reached a peak at 2 weeks of age in all breeds, averaging 93.2%. It declined rapidly thereafter and reached 15.7% at 10 weeks of age. The growth rate was the highest in CV×NH at 2 weeks of age, being 119%. Gain in body weight was 21g for the first week and increased with the advance in age, reaching 160g in the 10th week.
6. Over-dominance in body weight at 10 weeks of age was observed in a few crossbreds, as BP×NH, WL×BP, and NG×NH. It was not observed in most crosses. Growth was such not so marked in the crosses which showed the Over-dominance. It seems that the utilization of heterosis bears no important meaning in accelerating growth in broilers.
7. No sex-linked inheritance in growth was observed generally. A slight maternal effect on growth was observed in the crosses of WR×BP, WR×WL, BP×WL, and NH×NG.
8. Feed conversion (feed consumed/gain in body weight) increased in all breeds with the advance in age. The feed conversion rate (average of both sexes) at 10 weeks of age in the pure breeds was 2.93 in WR, 3.09 in NH, 3.25 in CM, 3.58 in WL, and 4.53 in NG. That in the crossbreds was 2.76 in WR×WL, 2.79 in NH×WR, 2.8O in CV×WR, and 2.85 in CV×NH. In general, the feed conversion rate was generally lower in the crossbred than in the pure breed.

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© Japanese Society of Animal Science
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