PERFORMANCE OF MORGAN HORSES UNDER SADDLE 29 
Slope of croup (top line of croup) was significantly associated with 
the riders’ scores for performance at walk, approached significance for 
time required to cover the 11.35-mile course, the time required to trot 
a mile, and the length of stride at the walk, and was significantly 
associated with the differences between the offspring of the various 
sires and offspring of sires within sexes. It was not significantly 
associated with sex. Average scores for the progeny of different sires 
ranged from 5.3 for Hudson’s progeny to 7.5 for those of Upwey King 
Peavine. Goldfield’s progeny averaged 5.4. 
Slope of shoulder was significantly associated with the time required 
to walk a mile (table 6) and with differences between sire-progeny 
groups within the same sex groups. It approached significance for 
differences between sexes and between sire-progeny groups. 
TRANSMITTING ABILITY OF THE SIRES 
The relative breeding value of the sires was indicated by comparing 
the average performance of the colts of a given sire with the average 
performance of colts by other sires from the same dams (table 9). In 
many of the comparisons the numbers were so small that only extreme 
differences could be shown to be significant, and it was not possible to 
consider the effects of years and sex. Apparently, no one stallion had 
superior transmitting ability in all characters. Canfield’s progeny, 
however, made the best showing when all the characters were con- 
sidered. Mansfield’s progeny, on the other hand, generally did not 
perform so well as those of the other sires. In regard to speed, stride, 
and temperament, it has been assumed in comparing the sires that the 
faster the speed, the longer the stride, and the higher the temperament 
score, the better were these characters. 
Style and beauty, although not directly related to performance, are 
generally desired in saddle horses and must be considered in selecting 
breeding stock. Differences between the progeny groups were found 
to be significant (table 18). The means for the progeny of the different 
stallions from highest to lowest were Mansfield, 7.7; Laddie, 7.5; 
Canfield, 7.2; Goldfield, 7.1; Hudson, 7.0; Upwey King Peavine, 6.5; 
and Abbott, 5.5. Delmont’s progeny were not scored for style and 
beauty. 
Determination of the transmitting ability of the sires is only partly 
covered by the tests reported in this study. Thus, Mansfield’s 12 colts 
that were tested are only a small sample of those sired by this stallion 
and may not have included the best. In fact 2 of his colts that were 
not available for testing have won the 100-mile trail rides of the Green 
Mountain Horse Association, indicating they had some excellent 
qualities. This fact does not detract from the findings of the pres- 
ent study but illustrates that the ability to evaluate the sires is lim- 
ited by the inadequacy of the tests and the samples tested. 
