Longevity of English Thoroughbred Horses 49 



• 58 years, which is significantly more than the global mean, 

 or the mean for any other group. The true difference is more- 

 over likely to be minimized, since nearly half the dams and 

 more than half the sires contributing to the global total died 

 at unkno^vTi ages or from accidental causes, and these losses 

 must include some potentially or actually long-lived pairs. 

 The difference in lifespan of fillies by the three selected 

 stallions out of long- and short-lived dams was about 1 • 3 

 times its standard error, but the short-lived mothers contri- 

 buted only 53 lives, even when the grouping limit was raised 

 to 18 years, and the comparison means little. 



In view of Vitt's opinions, a table of the early progeny of 

 long-lived parents was also made, taking all the available 

 mares from all the scored samples w^hose dam and sire were 

 aged 15 or less at the time of foaling or conception, but lived 

 eventually to an age of 23 or more, thus avoiding competition 

 between any age effect and inheritance of longevity. The 

 performance of these mares was in fact numerically but not 

 significantly poorer than that of the groups scored without 

 regard to parental age (e^^^ = 17-09 ±0-89 years). 



Goat colour 



Five cohorts (1875 — 79) were scored for coat colour — of 

 1,271 mares composing them, 588 were bays, 181 browns, 262 

 chestnuts, 27 blacks, 5 greys, 3 roans and 2 grey-roans, the 

 balance being of doubtful or unstated colour. In order to 

 compare the less common coat colours, further records of 

 greys and blacks were collected from other volumes of the 

 Stud Book. Brown mares were excluded because of the 

 heterogeneity of coat colours included under this description; 

 so were all individuals of doubtful colour, e.g. " black or grey", 

 at first registration. 



Of the colours examined (Table II), only greys appear to 

 diverge significantly from the means calculated for all mares 

 (P < 0-01) (Fig. 1). There was no significant difference 



