Agriculture Reference
In-Depth Information
Table 15.3
Heritability values
1
and phenotypic correlations for Angora goat traits.
Trait
Trait
2
GFW
CY
CFW
AFD
ASL
MF
KF
FCS
BW
Heritability range
0.07 - 0.45
0.02 - 0.48
0.12 - 0.38
0.08 - 0.33
0.07 - 0.42
0.00 - 0.39
0.05 - 0.42
0.08 - 0.24
0.07 - 0.50
Average heritability
0.16
0.34
0.16
0.18
0.33
0.25
0.18
0.22
0.26
Phenotypic correlations
3
0.23
4
GFW
—
0.95
0.50
0.21
0.15
0.04
0.25
0.09
CY
0.07
0.18
0.36
−
0.01
−
0.17
0.11
−
0.03
CFW
0.57
0.33
0.15
−
0.01
0.29
0.08
AFD
0.31
0.40
0.08
−
0.03
0.12
ASL
0.04
−
0.05
0.07
−
0.03
M F
0.60
− 0.13
0.08
K F
− 0.13
0.05
FCS
−
0.17
1
Heritability values from numerous sources.
2
GFW = grease fl eece weight, CY = clean yield, CFW = clean fl eece weight, AFD = average fi ber diameter, ASL = average
staple length, MF = med fi bers, KF = kemp fi bers, FCS = face cover score, BW = body weight.
3
For yearling males in a central performance test (Pfeiffer et al., 2004).
4
Correlation coeffi cients in bold font are signifi cant at
P
<
0.001.
traits character (h
2
= 0.14 - 0.34), style (h
2
= 0.13 - 0.23),
staple type, or luster. Snyman and Olivier (1999) presented
the values in parenthesis for South African Angora goats.
Pfeiffer et al. (2004) reported phenotypic correlations
for yearling Angora males on performance tests (7 years
data, n = 462). See Table 15.3. Most are favorable, but
three important exceptions are the positive correlations
among average fi ber diameter and body weight (r = 0.12),
clean fl eece weight (r = 0.57), and staple length (r = 0.31).
By selecting exceptional animals that do not exhibit these
general trends, individual breeders have successfully bred
goats to produce greater fl eece weights containing fi ner
mohair. Gifford et al. (1991) reported phenotypic and
genetic parameters of fl eece traits for Australian Angora
goats and pointed out that comparable parameters were
already available from U.S., Turkish, and New Zealand
sources.
goats, the reported heritability values (Table 15.4) for
cashmere goats are high. The phenotypic relationships
between BW and fi ber traits are either positive or not
signifi cant, and an unfavorable phenotypic (and genetic)
relationship exists between average fi ber diameter and
down weight. Other traits that have been considered for
inclusion in cashmere selection programs include average
staple length of down, secondary follicle density, S : P fol-
licle ratio, change in average fi ber diameter with age, and
cashmere style (subjectively assessed) that have heritabil-
ity estimates (reported in one study, Pattie and Restall,
1992) of 0.70, 0.17, 0.29, 0.21, and 0.16, respectively. The
scoring of cashmere style is subjective and inaccurate.
Although considered by many breeders and fi ber purchas-
ers to incorporate an overall subjective assessment of
down length, fi neness, luster, and crimp, one study with
U.S. cashmere (Lupton et al., 1999) demonstrated that
subjectively assessed style scores can be accurately pre-
dicted with only two objectively measured traits, average
fi ber curvature, and standard deviation of fi ber curvature.
In view of the recently reported study of McGregor (2007)
in which he identifi ed 11 different forms of cashmere fi ber
crimp that were related to the national origin of the fi bers
(Australia, China, and Iran), this simple relationship
between curvature, variability, and style score may not be
applicable to cashmere from all sources.
Cashmere Goats
Much of the genetic data relating to cashmere production
was generated in Australia, New Zealand, and China
although some of the latter information was diffi cult to
access. Quantitative traits that were included in breeding
objectives published by Pattie and Restall (1992) are pro-
duction of down, down average fi ber diameter, and live
weight. Compared to the comparable traits in Angora
