Íslenskar landbúnaðarrannsóknir - 01.03.1979, Side 89

TRAITS IN ICEL. TOELTER HORSES I. 87
RESULTS
Influence of environmental factors
The results of the analyses based on model
(1) showed that, with the exception of
height, cannon and legs score, the iníluen-
ce of district of origin did not significantly
affect the studied traits. Although the
residual mean square is somewhat biased
upwards, as previously mentioned, this
was taken to indicate that the effect of
district is not important, and it is ignored
in subsequent models. The effect of year
was significant for all the characters and
significant estimates of effects of age and
sex were observed for various characters.
The least squares means for sex are given
in table 4. Significant differences are obs-
erved for all the body measurements but
just for three of the subjectively scored
traits (legs, gallop and character).
The effects of age on body measurem-
ents were not significant except for girth,
which increased with increased age from 4
to 9 years. The three subjectively scored
traits of body conformation are not signif-
icantly affected by age, nor is character.
For the other traits, increasing age from 4
to 6-8 years on average results in higher
score marks.
The effect of different years of show are
very obvious. But on the other hand an
indication of a constant directionai trend
is not clear for most of the characters. If
TABLE 4.
Last-squares means and standard errors.
Stallions Mares Geldings M
Number of obesrvations . . . 219 808 144 1171
Height 140.55±0.52 139.69±0.48 141.26 ±0.55 140.50±0.48
Circumference of girth .... 157.13+0.77 159.58±0.70 159.24±0.82 158.65±0.70
Circumference of knee .... 29.19+0.14 26.93±0.12 28.18±0.15 28.10±0.12
Circumference of cannon . . 17.87 ±0.10 17.02±0.09 17.85±0.11 17.58±0.09
Form 7.92±0.05 7.91 ±0.04 7.98±0.06 7.94±0.05
Proportions 7.91 ±0.04 7.90±0.03 7.93±0.04 7.92±0.03
Legs 7.85±0.04 7.92±0.04 7.84±0.05 7.87±0.04
Toelt 7.85±0.09 7.72±0.08 7.74±0.10 7.77±0.08
Trot 7.84±0.08 7.82±0.07 7.80±0.09 7.82±0.07
Pace* 6.86±0.19 6.90±0.18 6.63±0.20 6.80±0.18
Gallop 7.70±0.05 7.81 ±0.04 7.85±0.06 7.79±0.04
Temperament 7.96±0.06 8.01 ±0.05 7.98±0.07 7.98±0.05
Character 8.21 ±0.07 8.03±0.06 7.97 ±0.08 8.07 ±0.06
Elegance 7.93±0.06 7.87 ±0.05 7.96±0.07 7.92±0.05
The standard error of the least squares means is calculated from seú+Bj = V(AjU/a + Abjbj + 2.\^b) al where Au denotes the appropriate inverse element of the inverse matrix, and crl denotes the variance component of the random error element. (Harvey, 1960)
non-pacers are included.