본 연구는 케이지와 평사 사육환경이 산란종계의 생산성에 미치는 영향을 알아보고자 실시하였다. 케 이지 또는 평사 사육환경을 제외한 모든 환경 조건은 동일한 산란종계 무창 계사를 선정하여 진행하였 다. 총 48주간 산란 종계의 산란율, 폐사율, 수정율 및 부화율을 측정하였다. 산란초기 산란율은 케이 지 사육 환경에서 높았으나, 전 구간을 보았을 때 37주 이후부터는 평사 사육이 월등히 높게 나타났다. 폐사율은 암컷 종계의 누적 폐사율에는 유의한 차이가 없었지만, 수컷의 폐사율은 케이지 사육환경에서 유의적으로 높게 조사되었다. 수정율은 전 구간 평사 사육이 월등히 높게 나타났다. 부화율에서도 평사 사육이 케이지 사육보다 높게 나타났다. 본 연구결과 평사 사육방식이 케이지 사육방법보다 산란종계의 수정율, 부화율 및 폐사율에서 우수한 것으로 조사되었다.

To elucidate the effect of feeding differently prepared CaCO3 (industrially purified limestone) on laying performance, egg shell quality and serum calcium and phosphorus concentration, totally 288 layers (52 wks old), with 16 birds per replicate, 3 replicates per treatment for six treatments were employed into the series of CaCO3 treatments followed by feeding study. Six CaCO3 treatment and diet preparation includes mash diet with naturally sized CaCO3 (MNaC), mash diet with coarsely particled CaCO3 (MCoC), mash diet with finely particled CaCO3 (MFiC), pelleted diet with naturally sized CaCO3 (PNaC), pelleted diet with casein coated CaCO3 (PCnC) and pelleted diet with agar coated CaCO3 (PAgC). Hen day egg production of the bird fed both fine CaCO3 and pelleted CaCO3 were lower (p<0.05) than those fed other CaCO3 diets. Although there is no difference in average egg weight among treatments, the weight tended to be heavier once the egg production rate was low. There is no difference in feed conversion ratio (intake/egg) among treatments. Egg shell thickness was the highest (p<0.05) with feeding of MCoC whereas the value was the lowest with feeding of pelleted CaCO3 diet. Although there is some difference in egg shell thickness, the shell breaking forces were not significantly different among treatments. Calcium content of the shell was the lowest (p<0.05) in the egg from the layer fed finely particled CaCO3. Serum Ca content tended to decrease up to 8 hrs after feeding, then tended to increase afterwards. Although both agar and casein coating of CaCO3 tended to retard the recovering increase of blood Ca, the difference needed to be clarified with individual ovulation cycle. Serum P level was generally decreased as time passed after feeding. Crude protein utilizability was the highest with feeding of agar coated CaCO3 and that of fat was higher with hens fed pelleted diets. Both ash and P utilizabilities of diet with finely particled CaCO3 were the highest among treatment although there were no differences in both energy and Ca utilizabilities. Conclusively, both the particle size of CaCO3 and pelleting of CaCO3 diet could affect shell quality of the egg. The effect was more evident by the differentiation of CaCO3 particle size than any other processing such as pelleting and coating.