48 A. Comfort 



the sires contributing to the sample. Life-tables were made (a) 

 for all the mares in sample A whose dams were known to have 

 reached the age of 25, or died before the age of 14, (b) for mares 

 in sample A whose sires reached 25 or died before 15, (c) for the 

 female progeny of those mares in sample A which reached 25 

 or died before 14, (d) for 113 mares in the sample whose dam 

 and sire both reached 23 years. The grouping limits in all 



Table IV 



Longevity of thoroughbred mares by longevity of parents 



( Years) 

 n ex=t Ve Median 



Mares foaled in 1875-80 



Sire reached 25 yrs.* 132 17-54 0-50 22-63 



Sire died ^ 14 113 16-27 0-60 22-53 



Dam reached 25 yrs. 238 16-96 0-16 22-25 



Dam died ^ 13 53 16-35 0-59 21-18 



Dam and sire reached 23 yrs. 113 18-07 0-34 23-74 



Progeny of mares foaled in 1875-80 



Dam reached 25 yrs. 168 16-33 0-31 22-54 



Dam died ^ 13 58 16-67 1-25 20-02 



Progeny of Hermit, Galopin and Hampton 



Dam reached 24 yrs. 100 17-11 0-82 21-52 



Dam died ^ 18 yrs. 58 15-39 0-83 21-51 



• Stallions whose date of death appears in the obituary lists ; mares by Hermit, Galopin and 

 Hampton are excluded from this figure, but included in the figure for dam and sire > 23 years. 



these cases were fixed to secure enough lives for the calcula- 

 tion; the relative contribution of short-lived mares to the 

 sample was so small that it was not possible to prepare a 

 table for the survival of their fillies by short-lived stallions. 

 The mares by the three long-lived stallions, Hermit, Galopin 

 and Hampton were also grouped by longevity of dam. 



The calculated means (Table IV) show differences of less 

 than twice the standard error in favour of all the groups with 

 one long-lived parent, except the progeny of long-lived mares 

 in the 1875-80 sample; the 113 mares with two long-lived 

 parents had a mean expectation of life at 4 years of 18-07 i 



