1910] ANIMAL, PRODUCTION. 773 



Blood fat in domestic fowls in relation to egg production, D. E. Warner 

 and H. D. Edmond (Jour. Biol. Chem., 31 {1917), No. 2, pp. 28 1-20 ff) .—The 

 percentages of lat (total ether extract) in samples of blood collected at the end 

 of October from 94 White Leghorn fowls at the Connecticut Storrs Experiment 

 Station are reported. 



The mean for 16 hens that had about completed their pullet year but which 

 were still actively laying is given as 1.109 per cent. The mean for 54 similar 

 yearlings that had stopped laying some time before (51.7 days on an average) 

 was 0.199. The mean for 12 hens at the end of their third year and not actively 

 laying was 0.171, and that for 12 cockereds was 0.176. The blood samples of the 

 males seemed to be much less variable in fat content than those of the females. 



The pullet year egg record of each of the 70 yearlings is also recorded. The 

 average of the laying birds is given as 162.8, that of the others as 139.1. Twelve 

 of the former and 6 of the latter were classified as having pale beaks, legs, and 

 vents. The average egg production of the 18 individuals was 168.2 and the 

 average blood fat content 0.816 per cent. Nine of the mature hens and 23 of 

 the inactive yearlings were classified as having yellow beaks, legs, and vents. 

 The average egg production of this group of 82 was 117.9 and the average blood 

 fat content 0.196 per cent. 



The following are some of the conclusions drawn from these facts : " There 

 is little or no correlation between the amount of fat in the hen's blood and her 

 yearly egg yield. On the other hand the blood of a hen laying at the time the 

 sample is taken is much richer in fat than that of a hen that is not lay- 

 ing. . . . There exists a close [negative] correlation between the color of 

 the beak, legs, and vent and the percentage of fat found in the blood, . . . 

 This would show that birds that were not laying were storing fat in the body 

 cells, and consequently their legs, beaks, and ani would become yellow, the 

 natural color for all American breeds and the Leghorns." 



The blood samples of 12 hens were known to have been taken after a 16- 

 hour fast. The average fat percentage was 0.009 higher than that of another 

 group of 12 which had not fasted. The difference is considered trifling. 



The cholesterol in the blood samples of '-\ few of the birds was determined by 

 the colorimetric method described by Bloor (E. S. R., 35, p. 13). The average 

 of 11 active layers was 0.114 per cent, of 7 inactive yearings 0.086 per cent, and 

 of 4 males 0.086 per cent. 



Note on the relation of blood fat to sex, and on the correlation between 

 blood fat and egg production in the domestic fowl, (). Riddle and J. A. Harris 

 {Jour. Biol. Chem., 34 {1918), No. 1, pp. i()/-i70).— Correlation coefficients be- 

 tween percentage of fat in the blood and the annual egg production are com- 

 puted from the data concerning yearling hens furnished by Warner and Edmond 

 in the paper noted above. For the 16 actively laying birds this correlation was 

 found to be -f 0.351 ±0.147 and for the 54 inactive birds —0.296 ±0.084. " Now, 

 while the probable errors of these correlations are large, because of the rela- 

 tively few determinations, the correlations suggest at once that while the birds 

 are laying those which have the highest percentages of blood fat are those which 

 make the highest egg records, but that after the bird has ceased laying in the 

 autumn those which have laid the greatest number of eggs during the year have 

 the blood most depleted of fat; or, at any rate, have blood with least fat." 



The inactive birds were further subdivided acc(jrding to the time elapsed since 

 laying ceased. For the 10 which had laid within 24 days the correlation was 

 -f 0.054 ±0.168. For the 22 whose Inactive period varied from 25 to 29 days the 

 correlation was —0.132 ±0.141, and for the 16 which had not laid for 60 or more 

 days it was — 0.620 ±0.103. Attention is called to the progressive change in 



