계육생산을 위한 부로이라종계의 육종개발에 관한 연구 ( 제2보 ) = A Study on Improvement of Broiler Breeder Stock for Broiler Production

다국어 초록 (Multilingual Abstract)

This study was carried out to improve broiler production arid to estimate a genetic value, and to select superior broiler breeder stocks by means of crossbreeding under domestic feeding and management conditions. Selection of superior stock in female lines: The data used in the study were the records of 18 single crosses produced by dialled cross of 4 strains of White Plymouth Rock and one strain of White Cornish, and added one strain of imported commercial parent stock. A total 1,283 chicks of crossbreds and purebreds mere used in this experiment. The results obtained in the study are summarized as follows; (1) The average date of sexual maturity was 193 days and the earliest sexual maturity was 185 days (O strain) and the latest sexual maturity was 206 days (S stain). The crossbreds had 8 days earlier sexual maturity than purebreds. (2) The average body weight at 24 weeks of age was 2,498g and the highest body weight was S strain (2,712g), and the lowest body weight was A strain (2,238g). There was no significant difference between crossbreds and purebreds, and between average body weight and recommanded body weight at 24 weeks of age. (3) The average adult body weight at 60 weeks of age was 3,625g and the highest body weight was 3,885g in S strain, and the low est body weight was 3,496g in A strain. In adult body weight for laying period was normally maintained body weight compared with breeder pullet feeding recommandations. (4) With respect to the laying hen viability the crossbreds were superior to the purebreds. The crossbred had about 5.1 percent lower mortality than the purebred. The death of the laying hens were due mainly to Lymphoid leukosis Complex. (5) The average hen-day egg production from 24 to 64 weeks of age was 51.60 percent and the highest egg production strain was T crossbred (65.04%), and the lowest egg production was B purebred (39.15%). The hen-day egg production appeared to be the most consistent of hybrid vigor. The crossbred averaged about 8.5% higher than the purebreds. The hen-housed average egg production was 144 eggs and the crossbreds were superior to the purebreds. The crossbred had about 20% higher egg production than the purebreds. In statistical analysis for combining ability in egg production, general and specific combining ability were significant. Consequently it seems to be important to be select dam and sire lines. The highest hen-housed egg production was 184 eggs in T crossbred. (6) In egg weight, the average egg weight was 61.96g grams and the highest egg weight strain was F crossbred (63.98grams), and the lowest egg weight strain was T crossbred (59.72grams). The crossbreds were superior to the purebreds in egg weight. (7) The average conversion of feed into egg production was 4.56㎏ and the lowest feed requirement strain (5.91㎏). Feed requirement of S strain which was imported broiler P.S. was 4.86㎏ of feed to produce per kilograms of eggs. With respect to the feed efficiency the crossbreds were superior to the purebreds. The crossbred had about 18 percent lower feed requirement than the purebreds. (8) In economic analysis of broiler breeder stock, the average of net income of per laying hen was 1,318won and the highest net income was T crossbred (2,552 won), and the lowest net income was B strain (-164 won), The average net income of S strain was 966 won. With respect to the cost of per egg production, the averages of per egg production cost was 33won and the lowest production cost was T crossbred (25.54 won). Egg production cost of S strain which was imported broiler breeder stocks was 35.44won and the S strain needed more cost to produce per egg was 9.79 won compared with the T strain. In the conclusion, the average performance of selected dam lines O and T strains was superior than the imported parents stock in the over all results of this experiment. A comparison of relative performance between selected superior female breeders and Arkansas meat performance e