EFFECTS OF INBREEDING AND CROSSBREEDING. 



33 



Table 8. — The 'percentage raised to 33 days of the young bom alive. Inbred stock by 



years, 1906 to 1920. 



[The average in Utters of each size and the index as in Table 7.] 



Year. 



Size of litter. 



In- 

 dex. 



Year. 



Size of litter. 



In- 



1 



2 



3 



4 



5 



6 



1 



2 



3 



4 



5 



6 



dex. 



1906 

 1907 

 1908 

 1909 

 1910 

 1911 

 1912 

 1913 



100.0 

 96.3 

 S9.9 

 84.6 

 91.1 

 83.1 

 85.8 

 80.0 



100.0 

 94.2 

 89.6 

 84.8 

 93.1 

 86.4 

 86.5 

 81.3 



97.4 

 92.6 

 90.4 

 86.7 

 92.6 

 88.0 

 86.6 

 75.4 



75.0 

 90.8 

 89.6 

 87.8 

 89.5 

 77.1 

 82.3 

 77.3 



*87."9" 

 88.3 

 89.2 

 82.2 

 80.2 

 66.1 

 75.5 



"90."9' 

 86.2 

 65.2 

 77.5 

 56.5 

 73.5 

 57.9 



94.0 

 93.1 

 90.0 

 86.1 

 92.0 

 84.9 

 85.6 

 78.0 



1914 

 1915 

 1916 

 1917 

 1918 

 1919 

 1920 



85.0 

 84.2 

 67.2 

 80.2 

 86.8 

 89.3 

 80.6 



91.3 

 87.5 

 72.0 

 74.6 

 75.8 

 89.4 

 88.0 



89.3 

 85.2 

 60.6 

 63.4 

 68.5 

 84.8 

 84.6 



79.2 

 80.2 

 58.0 



57.1 

 61.0 

 69.0 



74.7 



81.0 

 56.2 

 38.2 

 100.0 

 57.1 

 50.0 

 64.5 



68.6 

 62.5 

 0.0 



100." 6" 



87.5 

 84.8 

 64.2 

 67.2 

 71.0 

 83.5 

 83.2 



Table 9. — The percentage raised to 33 days of all young born. Inbred stock by years, 



1906 to 1920. 



[The average in litters of each size and the index, as in Table 7.] 



Year. 



Size of litter. 



In- 

 dex. 



Y r ear. 



Size of litter. 



In- 



1 



2 



3 



4 



5 



6 



1 



2 



3 



4 



5 



6 



dex. 



1906 

 1907 

 1908 

 1909 

 1910 

 1911 

 1912 

 1913 



100.0 

 83.9 

 77.2 

 75.4 

 77.9 

 64.1 

 71.8 

 64.3 



100.0 

 85.1 

 77.2 

 75.5 

 84.6 

 73.1 

 79.0 

 69.9 



97.4 

 84.8 

 78.5 

 75.2 

 84.8 

 75.9 

 74.5 

 68.4 



75.0 



82.0 

 75.5 

 70.8 

 76.3 

 57.5 

 71.2 

 60.6 



"78.5 



72.2 

 70.7 

 65. 5 

 43.1 

 43.1 

 59.2 



55. 6 

 59.5 

 47.8 

 55. 1 

 36.1 

 37.9 

 36.7 



94.0 



84.2 



77.4 1 



74.4 I 



82.3 



70.1 



74.9 



66.9 



1914 



1915 

 1916 

 1917 

 1918 

 1919 

 1920 



68.9 

 72.7 

 53.7 

 67.0 

 71.9 

 60.2 

 66.7 



83.3 



78.7 

 57.8 

 60.7 

 64.7 

 79.5 

 79.1 



80.0 

 72.6 

 44.7 

 45.9 

 52.1 

 75. 5 

 70.0 



65.2 

 63.5 

 29.6 

 34.4 

 43.5 

 48.6 

 54.1 



54.4 

 36.0 

 14.4 

 40.0 

 26.7 

 25.4 

 50.0 



53.0 

 13.9 

 0.0 

 0.0 



'4L7" 



76.9 

 72.6 

 46.5 

 50.2 

 56.1 

 69.8 

 69.2 



Table 10. — The average birth weight in grams. Inbred stock by years, 1906 to 1920. 

 [The average in litters of each size and the index, as in Table 7.] 





Size of litter. 







Size of litter. 





Year. 





In- 

 dex. 



Year. 





In- 



























dex. 





1 



2 



3 



4 



5 



6 







1 



2 



3 



4 



5 



6 





1906 



104.5 



110.7 



81.2 



67.4 







89.6 



1914 



106.5 



93.0 



80.2 



69.3 



62.3 



57.8 



84.5 



1907 



100.3 



89.5 



77.1 



67.6 



61.8 



54.1 



81.2 



1915 



97.4 



87.4 



72.9 



63.8 



53.5 



52.8 



77.9 



1908 



107.4 



90.1 



78.8 



72.0 



64.4 



58.0 



83.7 



1916 



89.9 



75.8 



63.9 



52.7 



46.9 





67.8 



1909 



102.4 



87. 6- 



76.2 



68.6 1 65. 8 



55.2 



80.7 



1917 



90.8 



72.6 



60.9 



49.6 



54.5 





65.1 



1910 



110.9 



95.5 



81.6 



72.3 



63.8 



60.1 



86.8 



1918 



93.1 



75.3 



63.3 



53.4 



53.1 





67.9 



1911 



102.7 



89.8 



76.7 



67.3 



60.4 



54.8 



81.4 



1919 



101.8 



87.1 



73.1 



61.0 



50.5 



39.5 



77.8 



1912 



102.2 



92.7 



78.6 



69.4 



61.6 



56.4 



83.4 



1920 



102.4 



86.0 



70.4 



62.5 



54.5 



48.7 



76.7 



1913 



103.8 



89.2 



78.3 



67.1 



62.4 



50.6 



-81.9 



















