Abstract
As a result of estrogen administration in White Leghorn chicken, it was recognized that the individual sensitivity have relation to her family's sensitivity, closely. Thereafter, the division of two strains about respective characteristic was attempted. In other words, the one was the sensitive strain, the other was the non-sensitive strain. The chicken acquired by means of sib-mating was offered in experiment. Diethylstilbestrol (solution of 50 mg. of stilbestrol in 20 cc of sesame oil) was injected intramuscularly to the chicken in 0.425 mg. daily dose. Estrogen injection was started on the 61 st day after hatching and continued for ten days. The sensitivity of chicken to estrogen was investigated from term which showed serum vitellin reaction. Results obtained here are briefly summarized as follows. ( 1 ) The sensitive group showed positive reaction in 67. 39, 75. 00% of all, but the non-sensitive group showed positive reaction in 28. 57, 29. 41% of all. ( 2 ) Significant positive correlation seems to be present between the term required in vitellin reaction and age at first egg. Namely, the coefficients of correlation were 0. 527 and 0. 619 in generation I and II, respectively. No significant correlation was present in intensity and clutch size. In conclusion, although it seems to be hazard to decide as the cases are few, it may be suggested that the difference of sensitivity in chicken due to the genetic control, and moreover it has relation to some of egg productive characters.
