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Influence of effects on quality traits and relationships between traits of the llama fleece
SmallRuminant Research Small Ruminant Research 24 (1997) 203-212
Influence of effects on quality traits and relationships between traits of the llama fleece Z. Martinez a, L.C. Iniguez b7*, T. Rodriguez a ’ Bolivian Institute for Agricultural Technology, P.O. Box 8452, La Paz, Bolivia b University of Wisconsin-Madison, IAP, 240 Ag Hall, I450 Linden Dr., Madison, WI 53706-1562.
USA
Accepted 3 July 1996
Abstract Differences owing to age, sex and coat color on fleece traits, and relationships between traits, were investigated in fiber samples of llama fleece. Fiber samples were obtained from five fleece regions of 143 llamas: withers; shoulder; ribs; loin-rump and thigh. The fleece composition was heterogenous and consisted of different proportions of unmedullated (20.2%). fragmented med (36.7%). continuous med (39.4%), and kemp (3.7%) fibers. Average diameter, diameter of coarse fibers, diameter of fine fibers, medullation percentage, average length, undercoat length, guard hair length, clean fleece yields and crimps per 2.54cm averaged 31.6p,m, 40.8bm, 2.5.5l.t.m, 43.1%, KOlcm, 8.34cm. 6.67cm, 82.3% and 6.1 crimps, respectively. Age was the most important differentiating factor (P < 0.05) for all traits. Medullation percentage and average diameter significantly increased with the age of the animal. The fleece of two-year-old llamas was the finest, averaging a similar diameter and medullation (25.5 pm and 27.5%) to that of Medium Adult alpaca fiber. Average diameter was significantly associated with medullation percentage (r = 0.78). It also appeared that the degree of medullation induced important changes in fiber diameter, determining larger diameters as the proportion of medullated fibers increased at a linear change rate of b = 0.195 km per unit of percentage of medullation (P < 0.01). Diameters of finer unmedullated and fragmented med fibers were highly correlated to coarse continuous med fibers (0.60 and 0.74, respectively); thus animals having finer undercoats also would tend to have finer guard hairs. Fiber lengths and crimps per 2.54 cm decreased with age (P < 0.01). Although of a magnitude with no practical implications, differences owing to sex (P < 0.01) were found on diameter of coarse fibers, undercoat length, medullation percentage, clean fleece yields and crimps per 2.54cm. The coat color was a factor of differences (P < 0.01) for medullation percentage. Colored fleeces were less medullated than white fleeces (36 versus 47%, respectively). Relative to the five sampled regions, samples from withers and ribs were more representative because of their better homogeneity (lower variation coefficients) and degree of association with the mean of all sampled regions. 0 1997 Elsevier Science B.V. Keywords:
Llama; fibers; Fleece quality; Fleece medullation; Fiber diameter
1. Introduction
Corresponding author. Fax.: [email protected] l
608 262 8852: E-mail:
00921~4488/97/$15.00 Published by Elsevier Science B.V PII SO921-4488(96)00925-X
The largest population of llamas, consisting of about two million head, is located in the Andean regions of Bolivia at elevations of 3800m above sea
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level and higher. In these regions, llamas contribute substantially to the economy of marginal production systems in a range of extreme environments that limit the development of other types of livestock. Llamas are raised primarily to produce meat while the production of fibers is secondary and destined mainly to fulfll the needs of the producer’s family, in particular for the elaboration of clothes, ropes and bags. The fleece of llamas in contrast to that of alpacas, is lighter, and its fibers coarser and more heterogeneous (Telleria, 1973). These characteristics have prevented wider utilization of llama fibers by the textile industry. New industrialized machines that can dehair the llama fleece have been developed, thus permitting direct inclusion of the finer fibers in textile tops and offering promising prospects for llama producers. Llama populations are unselected and show wide variability in many fiber production traits. Little is known about the nature of this variability, particularly for quality traits of the fleece related to industrial acceptability. This study was designed to identify (1) factors affecting quality traits of the llama fleece, particularly those occurring during the production life cycle, and (2) relationships among fleece traits. 2. Materials and methods Fleece samples from 143 llamas, 60 males and 83 females, were obtained from the flock of llamas of the Bolivian Institute for Agriculture Technology (IBTA), at the Patacamaya Research Station (3800 m altitude), La Paz, Bolivia. Animals ranged from two to eight years of age and their coat colors were classified as completely white, completely colored, and mixed. Animals were maintained under similar management based on open range grazing from 0800 to 1630 with free access to water, and confinement in open corrals during the night. Mating and lambing seasons overlapped from mid-December to midMarch. Animals were shorn first at 21-22 months of age, and thereafter annually. Thus, in two-year-olds, the growth period of the fleece corresponded to the age of the animals, while in older animals the shorn fleeces represented one year’s growth. Shearing occurred in October, at the end of the dry season.
Birthdates, liveweights and fleece weights for each animal were recorded regularly. Fiber samples, each weighing 60-lOOg, were taken for analysis at shearing from tive fleece regions of a given animal. The regions were: withers (W), shoulder (S), ribs (R), loin-rump (LR) and thigh (T) (Fig. 1). 2. I. Laboratory analysis Fiber diameter was obtained by microprojection, according to ASTM (1991a) standards. A sample size of n = 300 individual fibers per sample was determined to provide a 95% confidence limit not greater than 0.7 units of the mean (Snedecor and Co&ran, 1967). Because of the great variation in types of fiber in each sample, individual projected fibers were classified according to presence of medulla (ASTM, 1991b) as: unmedullated, fragmented med (with fragmented and interrupted medulla), continuous med (those in which the diameter of continuous medulla was greater than 60% of the diameter of the fiber) and kemp (in which the diameter of the continuous medulla was less than or equal to 60% of the diameter of the fiber). Diameters of each type of fiber were measured. Two categories of fibers were also considered: fine (including unmedullated and fragmented med fibers) and coarse (including continuous med and kemp fibers). Average diameters of unmedullated (DUN), fragmented med (DFM), continuous med (DCM), kemp (DK), fine (DF) and coarse (DC) fibers, along with a general average including all fiber types (DA), were calculated for each sample. To facilitate medullation measurements of colored fibers, fiber specimens were treated for 24 h with H,O, prior to their microprojection.
Fig. 1.
Body regions from which fleece samples were obtained: withers (W), shoulder (S), ribs (R), loin-rump (LR)and thigh (T).
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Proportions of unmedullated, fragmented med, continuous med and kemp fibers in a sample were obtained (UN%, PM%, CM%, and K%). Medullation (M%) was calculated as a percentage of continuous med and kemp fibers of all measured fibers in a sample. Length was taken from the external coat of coarser fibers or guard hairs (LG) and from the undercoat crimped fibers (LU), after dehairing a subsample by hand. Five measurements per subsample of fibers without stretching were made in each category. An average length per sample (LA) was obtained from LG and LU. The number of crimps per 2.54cm (NC) was measured with the Staple-Crimp Scale on 30 fibers randomly obtained per region per sample, without stretching or disturbing the crimps. Yields of clean fleece (Y%) were obtained for each sample on a subsample of 18-20 g of fibers that was washed with detergent and Na,CO, solutions, rinsed in water at 5O”C, dried, and weighed at approximately 16% relative humidity. 2.2. Statistical analysis Analysis was on averages of the different traits per region per animal. The observations among regions were not independent but actually repeated measurements of the same variable in a given animal, thus a test of independence using Mauchly’s sphericity criterion @AS, 1987) was conducted along with a within- and between-subjects univariate analysis. The basic linear model to test the influence of fixed effects in producing changes in each of the analyzed traits, included the following effects: age (i,: i = two,.., eight years), sex (j, j = 1: male and j = 2: female), white), k = 2 coat color (k,: k = 1 (completely (completely colored) and k = 3 (mixed)) and five regions as repeated measurements. Only interactions among regions and the other fixed effects were included in the model. Other interactions were pooled in the error term since their effect was non-significant. In analyzing fiber diameters the basic linear model was expanded to include medullation traits as covariates, in order to inspect whether fiber diameters changed as a consequence of different degrees of medullation.
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Pairwise correlations among traits were obtained. In view of the influence of sample size on the statistical significance of the correlation coefficients, which could be regarded as significant even when the actual estimates of r approach zero, it was decided for discussion purposes that r > 0.55 reflected high association, 0.46 I r I 0.55 medium association, 0.25 I r I 0.45 a weak trend and r < 0.25 low association or independence. To determine a representative region of the five regions sampled in this study, effects owing to sex, age and coat color were first removed after correcting the data, without affecting the variation owing to regions. With the adjusted data, the homogeneity and degree of association of the regions were studied through ranks and functions of ranks. To analyze average homogeneity, CVs for each of the p regions (p = 1 (WI; p = 2 (S); p = 3 (R); p = 4 (LR); and p = 5 CT)) within a given trait q (q = 1,..9) were ordered by ranks (H,,), assigning lower ranks (one the lowest) to coefficients that reflected lower variability and five to the highest CV. Then all ranks of a particular region were added over all nine traits, obtaining a set of five sums (H,) per region. In this set lower sums expressed more homogeneity over all traits. To analyze the degree of association, within a trait (q) the set of five correlations between regions (p) with an average of all regions was ordered also by ranks (Ap4). Lower ranks (one the lowest) were assigned to higher correlations and higher ranks (five the highest) to lower correlations. A,,s of a given region (i) were added over all traits to obtain a set of five sums (A,). In this set, lower sums assigned to lower ranks expressed greater association of a given region with the average of all regions. H, and A, were finally added to obtain a global function of ranks flH,A) based on a set of five sums. This set was also ranked to decide the representativeness of the sampled regions.
3. Results and discussion 3. I. Quality components of the llama fleece Table 1 summarizes the analysis of the influence of effects on the studied traits, after removing the effect owing to correlated repeated measurements
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Table 1 Effects of age, region, sex and coat color on quality traits of the fleece of llama Tests and sources of variation
X2 Significance
’
Tests within subjects Region Region X sex Region X age Region X color Tests between subjects Sex Age Color
Fleece
COmpOnentS
DA(pm)
DC(pm)
DF@m)
M%(%)
LU (cm)
LG(cm)
LAhd
Y%(s)
NC(n)
17.0
7.9 ns
18.0 *
29.9 *t
24.6 *
15.5 **
17.7 t*
8.7 ns
27.8 1.
t* tt tt
**
.*
.
ns tt
ns
ns
ns
ns ns ns
ns ns ns
** ** *t
ns *t
ns If
** t
** tt
ns
l
l
tt t. ns ns
ns ** ns
** ns ns ns
l
tt tt
l
*
tt tt ns
*
ns tt ns
ns ** ns **
ns ** * l
l
l
ns l
* *
*
ns
ns
a Sphericity chi-squared test for multicolinearity with 9 degrees of freedom; DA: average fiber diameter; DC: diameter of coarse fibers; DF: diameter of fine fibers; M%: medullation; LU: length of undercoat; LG: length of guard hairs; LA: length of all fibers; YW: clean fleece yield; NC: number (n) of crimps per 254cm. _ * : P < 0.05; ’ * : P < 0.01; ns: P > 0.05.
(regions). For all traits except for DC and Y%, the sphericity test revealed the presence of multicollinearity (P < O.Ol), which justified the utilization of tests of hypotheses for between-subjects and univariate tests for within-subjects effects. The main interest was in differences owing to age, sex and coat color. Nevertheless the within-subject analysis also revealed an important contribution of regions to the differences observed in most of the traits (P < 0.051, except in the case of M% (P > 0.05).
3.2. Diameter The averages and associated statistics of the different types of fibers are included in Table 2. Microscopic distinction of fibers yielded better estimates of diameters of fine and coarse fibers than those obtained in former macroscopic assessments (Riera, 1969; Tellen’a, 1973). The average diameter (31.6 pm for n = 214500; Table 2), was in the range of reports by Chivilchez (1959) Von Bergen (1963) and Castro (1988) and was slightly higher than averages reported by Onions (1962), Riera (1969) and Rodriguez (1981). Comparatively, alpaca average lower diameters in a range of 21-28 km ( Onions, 1962; Von Bergen, 1963; Flares, 1979; Espeztia,
1986). The average and SD estimates in this study were comparable to those of Alpaca Class A (adults with a lZmonths-growth fleece), according to ASTM (1991c) standards. Fine llama fibers, classified macroscopically as apparently unmedullated by Telleria (1973) yielded diameters (24.8 pm) comparable with those of fibers classified as fine in this study (25.5 km, with lowest and highest mean values of 18.1-37.7pm, respectively; Table 2). DUN averaged 22.7 p,rn (with mean values ranging from 16 to 32.4 pm; Table 2) within the range of Alpaca Class T (yearlings first shear, with lZmonths-growth fleece) in accordance with ASTM (1991c). Unmedullated and fragmented med fibers of alpaca varied from 15 to 20 pm and from 20 to 30 km, respectively; while kemps varied from 40 to 60 pm (Calle, 1982). Therefore, as opposed to the general belief, unmedullated fibers of llama measured in this study were not finer than unmedullated alpaca fibers. Age was an important cause of differences (P < 0.01) in diameter of fibers (Table 1) which, consistently tended to increase at older ages (Fig. 2 and Table 3). DA in two-year-old llamas were 26% lower than those in older animals (25.5 versus 32.2 brn, respectively, P < 0.01). The linear rate of increase of DA was 1.37 pm per year (P < 0.01).
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Table 2 Mean diameters and lengths of llama fibers Average
Traits
E
Min
Max
SD
cv (%I
hi n2 *3
31.6 25.5 40.8 22.7
21.3 18.1 26.9 16.0
49.9 37.7 59.4 32.4
5.29 3.23 4.74 2.75
17 13 12 12
143 x 5 x 300 143 x 5 x 171 a 143 x 5 X 129 a 143X5X61a
5.44 9.00 7.22
2.86 5.12 4.12
15.22 21.28 17.86
1.82 2.49 2.08
33 28 29
143X5X5 143 x 5 x 5 143 x 5 x 10
5.01 8.34 6.67
2.86 5.12 4.12
10.96 13.52 11.79
1.18 1.31 1.16
23 16 17
126X5X5 126X5X5 126 X 5 X 10
Diameter (wrn)
AII fibers (DA) Fine fibers (DF) Coarse fibers (DC) Unmedullated fibers Lengths (cm) All observations
Undercoat (LU) Guard hairs (LG) All fibers (LA) Excluding a-year-old llamas
Undercoat (LU) Guard hairs (LG) All fibers (LA)
n,: number of llamas; n2: number of regions per llama; ns: exact number of fibers per sample or a average sample size based on distributions of fiber types per sample; SD: standard deviation; CV: coefficient of variation.
with age were also documented in the literature (Telleria, 1973; Riera et al., 1972; Rodriguez, 1981; Castro, 1988).
Changes in diameter were due mainly to changes in DUN, DFM and DCM, which increased (P < 0.05) with age at significant linear rates of 0.61, 0.80 and
Changes
Table 3 Estimates of effects contributing to differences in diameter and length of fibers, percentage of meduliation, clean fleece yield and fiber crimp numbers in llamas Main effects
nt
Sex Mates Females
DA (km)
DC (km)
DF(t.cm)
LG(cm)
LU(cm)
LA(cm)
MI(%)
Y%(%)
NC (n)
(60X 5) (83 X 5)
31.8 30.7
43.0a 39.4b
25.8 24.9
9.6 9.2
5.9a 5.3b
7.6 7.3
38.2 42.8
83.3a 81.8b
6.4a 6.0b
(17 X 5) (22 x 5) (25 x 5) (10x 5) (14 x 5) (20 X 5) (35 X 5)
25.5a 29.6b 30.6bc 31.3cd 34.Oe 33. lef 34.8e
37.3a 4O.lb 41.2c 41.7cd 42.4cde 41.7cdef 43.73
21.9a 24.5b 25.4c 24.9bcd 26.8e 26Sef 27.3e
13.9a 9.3b 8.7~ 9.3bd 7.6e 7.9ef 7.9ef
8.4a 5.6b 5.2~ 5.9bd 4.5e 4.9cef 5.Ocf
11.2a 7.4b 7.Oc 7.6bd 6.le 6.4ef 6.4ef
27.5a 36.9b 36.6bc 41 .Obcd 48.le 44.6def 48.7ef
82.8a 83.2ab 83.2abc 82.6abd 8 I .7de 83.0abcdf 81.2e
7.la 6.4b 6.2~ 6.2cd 6.0cde 6.1cdef 5.7g
(75 x 5) (38 x 5) (30 x 5)
31.7 31.4 30.7
4O.Oa 43.Ob 40.5a
25.1 25.6 25.2
9.2 9.0 9.6
5.6a 5.lb 6. lc
7.4a 7.Ob 7.9c
46.6a 35.5b 39.4c
82.2 82.9 82.5
6.2 6.3 6.2
Xn2
Age (years)
2 3 4 5 6 7 8 Coat color
Whole: White Colors Mixed
n,: number of llamas; n2: number of regions per llama; DA: average fiber diameter; DC: diameter of coarse fibers; DF: diameter of fine fibers; LG: length of guard hairs; LU: length of undercoat; LA: length of all fibers; M%: medullation; Y%: clean fleece yield; NC: number (n) of crimps per 2.54cm. ab,c,d,e,f,g estimates in a column within a given effect without a common letter differ (P < 0.05).
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208
+ Medullatian
0
.I___. 2
__(___ 3
4
6
8
7
Medullation
percent
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r60
i-0 8
Age (yr) *
Average
diameter
-
Fig. 2. Changes of average diameter (DA) of fibers and percentage of medullation CM%) with the age of llamas.
0.83 km per year. Contrastingly, DK remained relatively unchanged (b = 0.096 pm per year; P > 0.05). Changes in diameter throughout the production lifetime deserve special attention because of its direct implications for the quality of the fleece, therefore it is suggested that future investigations focus on its physiological nature. Fig. 3 illustrates changes in the proportion of fine fibers with diameters less than 25 p,rn and fibers with diameters greater than or equal to 25 p,rn at different ages. In two-year-old animals, 48% of the fibers had diameters less than 25 km, this proportion was three times smaller at the age of three years, five times smaller at the age of four years and 12 times smaller in animals older than four years. Fibers with diameters greater than or equal to 25 p,rn increased correspondingly. This suggests the need to shear animals in groups of similar ages to obtain better returns; in particular groups of younger animals whose fleeces could be marketed at prices similar to those of alpaca. Coarse fibers of females were 3.6 pm finer than those of males (P < 0.05). Although differences owing to coat colors were unimportant (Table l), DUN, DFM, DCM and DK, according to the coat color categories, ranked white < mixed < colored (P < O.Ol>, suggesting that white fibers tended to be finer than colored. Reports on differences in the diameter of fibers owing to sex and coat colors (Telleria, 1973; Rodriguez, 1981) contrasted with others that did not confirm the results of this study (Amolds, 1964; Castro, 1988).
The diameters of finer fibers, DUN versus DFM, were highly correlated (r = 0.82) (Table 4). Similarly, a high association was found between diameters of finer and coarser fibers; DUN versus DCM (r = 0.60) and DFM versus DCM ( r = 0.741, respectively. Therefore, animals with finer undercoats also would have finer guard hairs. Diameters of the different types of analyzed fibers were not associated with DK. As it would be expected, a high negative association (r = -0.57; P < 0.01) was observed between DA and NC, because coarse med fibers are not likely to curl. Diameters and length of fibers evidenced weak or low association within the undercoat (DUN versus LU with r = -0.27; and DFM versus LU with r = -0.23, respectively), and within guard hairs (DCM versus LG with r = -0.24 and DK versus LG with r = -0.08, respectively) (Table 4). 3.3. Medullation UN%, FM%, CM% and K% accounted for 20.2, 36.7, 39.4 and 3.7%, respectively. Thus, 79.8% of the fibers in the fleece of llama consisted of medullated fibers. The average percentage medullation CM%), corresponding to the proportion of continuous med and kemp fibers, was 43.1%, with mean values ranging from 3.3 to 97%, SD = 21%, and CV = 49% (n = 2 14,500). Differences in medullation owing to age and color of the coat were important (P < 0.01; Table 1). The
% fibers loo-
Fiber diameter SO-
60.
I
45-49.9
y
Baa
40-44.9
y
35-39.9
”
20
./
0 I-l 2
3
4 Age (yr)
Fig. 3. Changes in the proportion of fine ( < 25 pm) and coarser fibers ( 2 25 pm) at different ages in llamas.
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Table 4 Correlation
coefficients
Traits
UN%
FM%
CM%
K%
DUN
DFhl
DCM
DK
LG
LU
UN% FM% CM% K% DUN DFM DCM DK LG LU
1
-0.15
- 0.78 - 0.48 1
- 0.47 - 0.37 0.56 1
-0.23 -0.12 0.29 0.08 1
- 0.07 - 0.23 0.22 0.02 0.82 1
0.15 - 0.27 0.06 - 0.03 0.60 0.74 1
-0.01 0.06 - 0.03 - 0.07 0.15 0.10 0.22 1
0.28 0.09 - 0.30 -0.22 -0.37 -0.36 -0.24 -0.08 1
0.27 0.08 - 0.28 - 0.20 - 0.27 - 0.23 -0.12 - 0.20 0.86 1
’ between components
1
corresponding
to tine and coarse fibers of the llama fleece (n = 715 pairs)
UN%: percentage of unmedullated fibers; FM%: percentage of fragmented med; CM%: percentage of continuous med; K%: percentage of kemps; DUN: diameter of unmedullated fibers; DFM: diameter of fragmented med; DCM: diameter of continuous med; DK: diameter of kemps; LG: length of guard hairs; LU: length of undercoat. a Levels of significance of correlation coefficients were: P > 0.05 if Irl< 0.08; P < 0.05 if 0.08 s Iris 0.09 and P < 0.01 if Irl > 0.09. Bold coefficients reflecting high association.
age-trend paralleled the pattern of diameters, as percentage medullation consistently increased at older ages (Fig. 2 and Table 3). The lowest M% (27.5%) was found in two-year-old animals which was different than M% at older ages (P < 0.01). Compared with two-year-old animals, M% increased from 33 to 34% at the age of three to four years and over 66% in animals older than four years. The rate of linear increase of M% was 3.2% per year (P < 0.01). The increase in medullation with age appeared to be directly caused by a net increase in CM% (b = 2.8% per year; P < 0.01) and K% (b = 0.4% per year; P < 0.05), than with changes in UN% (b = - 1.7% per year; P > 0.05) and FM% (b = - 1.6% per year; P > 0.05). While a low association was found between UN% and FM% (r = - 0.15>, CM% was highly correlated to K% (r = 0.56; Table 4), suggesting that fleeces high in continuous med would tend to be also high in kemp. It is interesting to contrast medullation across different species of camelids which, to some extent, may have a genetic basis: alpaca Suri 42.6% (Bellido, 19501, alpaca Huacaya 21%, one-year-old guanacoes 14% (Defosse et al., 19811, and vicuna 4.5% (Carpio and Solari, 1982). In addition, diameters of fibers also tend to decrease in the same order suggesting a positive relationship between diameter and degree of medullation. A high relationship between DA and M% (r = 0.78) was found in this study.
Moreover, the correlations of DA with UN%, FM%, CM% and K% were also high and in the expected direction: r = -0.59; r = -0.41; r = 0.77; and r = 0.57, respectively. It also appeared that the degree of medullation induced important changes in fiber diameter, determining larger average diameters as the proportion of medullated fibers increased at a linear rate of change of b = 0.195 km per unit of percentage medullation (P < O.Ol>, with intercept at 24 pm. Consistency in rates of change was observed within diameter components, as linear change rates of DUN ( - 0.032 km per unit of UN%, P < 0.01) and DFM (- 0.030 km per unit of FM%; P < 0.01) were negative, contrasting with positive linear rates of DCM (0.019 p,m per unit of DC%; P < 0.05) and DK (0.143 p,rn per unit of K%; P > 0.05). Weak correlations between %M and LA (r = - 0.3 1) were consistent with the estimates of Chavez (1991). The fleece of colored animals was found to possess less medullation than that of white animals (P < 0.05>, which is in agreement with Arnolds (1964) on llama and with Ruiz de Castilla and Olaguibel (1991) on alpacas. 3.4. Length offibers Average lengths of different types of fibers were included in Table 2. Undercoat fibers exhibited more variation than guard hairs (CV = 23% versus 16%).
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Age contributed to important differences (P < 0.01; Table 1) in the length of all fibers. The estimation of age effects (Table 3) revealed a reduction in the length of fibers at older ages: a trend also reported by Castro (1988) and Rodriguez (198 1). With an average LU ranging from 4.5 to 5.6cm and LA from 6.1 to 7.4 cm (Table 31, the fleece of lamas over two years old grown in one year could be utilized by the industry with no restrictions, however its medullation (36.6-48.7%; Table 3) and larger average diameter (29.6-34.8 pm; Table 3) could be limiting. A dehaired fleece or a fleece from animals with capacity to produce with lower M%, could permit its direct utilization in industrial processes opening important currently non-existent opportunities for llama producers. If continuous med and kemp fibers could be removed by dehairing, the remaining fleece, at the most, would have the diameter of fine fibers (25.5 Frn; Table 21, and be marketed as Medium Adult or Extra Fine alpaca fibers (ASTM, 199 lc). Contrastingly, the fleece of two-year-old animals has remarkable features. In fact, with LU 8.4 cm, DA 25.5 p.rn and M% 27.5% (Table 31, the fiber of these animals fit textile requirements well and could compete directly and advantageously with Medium Adult alpaca fibers (ASTM, 1991~). It is estimated that 200000-250000 head of two-year-old unshorn llamas, producing a yield of at least 1 kg per animal, would have the potential to contribute no less than 200 t of fine fiber if the animals were shorn. A strong association among LU and LG ( r = 0.86) was found. The color of the coat contributed to differences in LU and LA. LA and LU in white animals were larger than in colored (7.4 versus 7.0cm and 5.6 versus 5.1 cm, respectively; P < 0.05; Table 3). Although of a magnitude with no practical implications, sex differences were found for LU (P < 0.05; Table 3).
SD 3.4% and CV 4% (n = 715). This yield was lower than yields observed by Espeztia (1986) and Blanc0 (1980) in alpacas (86.7 and 88.8%, respectively). The average of 6.1 crimps per 2.54cm, with mean values ranging from 4 to 9.9 crimps, SD 0.89 crimps and CV 15% (n = 21,450), was comparable with counts obtained by Ruiz de Castilla and Olaguibel (1991) in alpacas (5.9 crimps per 2.54cm). Sex differences (P < 0.05; Tables 1 and 3) with no practical implications were found for both Y% and NC. NC declined at older ages (P < 0.01; Tables 1 and 3) possibly as a direct consequence of changes in medullation and fiber diameter of fibers. Crimps per 2.54cm in two-year-old llamas were higher than those in older animals (7.1 versus 6.1 crimps per 2.54cm in two-year-old and older llamas, respectively). Y% also reduced at older ages (P < 0.05; Tables 1 and 3), however, the magnitude of the changes had no practical implications.
Table 5 BLUE estimates of live weight classified by sex age and color
and fleece of weight
of llamas
Main effects
n
Fleece weights (kg)
Live weights (kg)
Sex Male Female
60 83
1.24a 1.03b
104.3a 91.3b
Age (years) 2 3 4 5 6 7 8
17 22 25 10 14 20 35
1.14 1.08 1.02 1.14 1.26 1.11 1.19
91.2a 98.6b 105.2b 105.4b 104.3b 101.9b 98.8b
3.5. Clean fleece yields and number of crimps per 2.54 cm
Coat color Completely white Completely colored Mixed
75 38 30
1.15a 1.04a 1.22ab
100.9 98.1 103.4
Clean fleece yields of llamas are known to be higher than those of many sheep breeds and most other fiber producing ruminants. Yields in this study averaged 82.3%, with a range from 70.7 to 89.7%,
n: number of llamas. a,b: estimates in a column within a given effect without a common letter differ (P < 0.05). Estimates in a column with no attached letters do not differ (P > 0.05).
Z. Martinez et al. /Small Ruminant Research 24 (1997) 203-212 Table 6 Ordering
P
of rank functions
by the degree of homogeneity
Regions
of a given region and its association
Withers (W) Shoulder(S) Ribs (R) Loin-Rump (LR) Thigh (T)
with the average of all sampled regions
Rank functions Homogeneity
1 2 3 4 5
211
H,. 23.5 19 28 29.5 35
Global
Association R 2 1 3 4 5
A,. 19 34.5 16.5 38.5 26.5
H,. and A,. sums of ranks over all q (q = L.9) fleece traits concerning association (A) with the average of all sampled p = 5 regions, respectively. AH,A) is the total sum of H,. and A,.
3.6. Liveweights and fleece weights All animals were in excellent body condition at shearing. Estimates of sex, age and coat color effects on liveweights and fleece weights have been included in Table 5. Average weight of two-year-old llamas (91.2 kg) was lower (P < 0.01) than that of older animals. Fleece weights were similar across ages (P > 0.05) and averaged 1.11 kg (SD = 0.30 kg and CV = 27%) in agreement with the estimate of Rodriguez (1981). Liveweights were uncorrelated to DA and M% ( r = 0.15 and r = - 0.09, respectively). Fleece weights were also uncorrelated to DA and M% (r = 0.008 and r = - 0.05, respectively). There was a weak association between fleece weights and liveweights (r = 0.42). 3.7. Degrees of representativeness among sampled regions Table 6 summarizes results concerning measurements of homogeneity and association to identify degrees of representativeness among the sampled regions. Over all traits regions ranked S > W > R > LR > T on the basis of their degree of homogeneity, i.e. having lower CVs. Regions, which on average were more correlated with an average of all sampled regions, ranked R > W > T > S > LR, according to their degree of association. Based on these results, the global function (Table 6) that takes into account measurements of homogeneity and association, suggested that W and R were more representative than the other sampled
Ranks
flH,A)
Ranks
2 4 1 5 3
42.5 53.5 44.5 68 61.5
1 3 2 5 4
the homogeneity
(H) of a given region
p and its degree of
fleece regions. Between these two suitable positions, R is likely to be the best because of its easy access for sampling. Considering that the whole fleece was not sampled, the average of all sampled regions does not correspond to the true average of the fleece. Thus, these results should be carefully interpreted in view of the fact that they do not apply to the whole fleece.
4. Conclusions The fleece of llamas consists of a mix of heterogeneous types of fibers ranging from unmedullated to kemp. Diameter and medullation increase in older animals affecting the industrial quality of the fleece, therefore shearing should be organized in similar age groups, so that the fleece of two-year-old animals could be directly marketed with competitive prices, similar to those of Medium Adult Alpaca fibers. The results suggest that the medullation condition is not only positively associated with diameter of fibers, but also causes changes in the diameter of fibers determining larger diameters as the proportion of medullated fibers, particularly of continuous med and kemp fibers, increases.
References ASTM, 199la. Annual Book of ASTM Standards. Desig. D213090 Standard Test Method for Diameter of Wool and Other Animal Standard Fibers by Microprojection. ASTM, Philadelphia, PA, Vol. 7 (01). pp. 581-589.
212
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Ruminant Research 24 (1997) 203-212
ASTM, 1991b. Annual Book of ASTM Standards. Desig. D296889. Standard Test Method for Med and Kemp Fibers in Wool and Other Animal Fibers by Microprojection. ASTM, Philadelphia, PA, Vol 7 (01). pp. 809-81 I. ASTM, 1991c. Annual Book of ASTM Standards. Desig. D225285 (Reapproved 1991). Standard Specification for Fineness of Types of Alpaca. ASTM, Philadelphia, PA, Vol. 07 (011, pp. 601-602. Amolds, I.C., 1964. Algunas caracteristicas fisicas de la tibras de llama. (Some physical characteristics of the llama fiber). Tesis Ing. Agr., Universidad Catolica, Santiago, Chile, 55 pp. Bellido, N.J., 1950. Estudios comparatives de 10s caractems fisicos de ianas y de las producciones piliferas de 10s Cam&lidos Americanos: alpacas. (Comparative studies of fiber and fiber production traits in the American Camelids: alpacas). Bol. Ganaderia, Minist. Agric., Lima, Peru, 3(7): 66-77. Blanco, V.M., 1980. Peso vivo, peso vellon y rendimiento de vell6n de alpacas de la C.A.P. Huaycho Ltda. (Body weight, and fleece weight and yield in alpacas from C.A.P. Huaycho Ltd.). Tesis Med. Vet. Zoo]., Universidad Tecnica de1 Altipiano, Puno, Peru, 36 pp. Calle, E.R., 1982. Production y Mejoramiento de Alpacas. (Production and breeding of alpacas). Fondo de Libra, Banco Agrario, Lima, Peru, 334 pp. Carpio, P.M. and Solari, Z., 1982. Diametro de la tibra en el velldn de la vicutia (Fiber diameter in the vicuna fleece). In: Informes de Trabajos de lnvestigacidn en Vicuiias, Universidad National Agraria, Programa de Ovinos y Cam6lidos Americanos. La Molina, Peru, Vol. I, pp. 54-105. Castro, F., 1988. Analisis de1 velldn comercial de 10s camehdos: alpaca y llama. (Analysis of the commercial fleece of llama and alpaca). Tesis Ing. Agric., Universidad Mayor de San Sim6n. Cochabamba, Bolivia, 79 pp. Chavez, J.F., 1991. Mejoramiento Genetico de alpacas y llamas. (Genetic improvement of alpacas and llamas). In: S. Femartdez Baca (Editor), Avarices y Perspectivas de1 Conocimiento de 10s Camelidos Sudamericanos. FAO, 172 pp. Chivilchez, J., 1959. Estudio Biometrico y estructural de la lana de auquenidos (alpaca, llama y vicuha). (Structural and biometric study of alpaca, llama and vicuna fiber). Rev. Patronato Biol. Anim., 2(4): 355-421. Defosse, A.M., Garrido, J.S., Laporte, O.J. and Duga, L., 1981. Cria de guanacos en cautividad, variation de su crecimiento y cahdad de su lana. (Raising guanacos in captivity; variations in fiber growth and quality). Centro Patagonico, Argentina, No. 45, 17 pp.
EspezGa, F.N., 1986. Longitud de mecha, rendimiento y di&metro de tibra en alpacas Huacaya en cuatro comunidades de la Provincia de Chucuito. (Fiber length, yield and diameter in Huacaya alpacas in four communities of the Chucuito Province). Tesis Med. Vet. Zool., Universidad Tecnica del Altiplano, Puno, Peru, 70 pp. Flares, A.H., 1979. Diametro y Longitud de mecha en alpacas Huacaya y Suri de1 Centro de ProduccMn La Raya. (Fiber diameter and length in Huacaya and Suri Alpacas from La Raya Production Center). Tesis Med. Vet. Zool., Universidad Tecnica del Altiplano, Puno, Peru, 3 pp. Onions, W.J., 1962. Wool: An Introduction to its Properties, Varieties, Uses and Production. Interscience Publishers, John Wiley and Sons, New York, 278 pp. Riera, S., 1969. Ritmo de crecimiento y tinura de1 pelo de la Ilama. (Growth and fineness of the llama fiber). Est. Exp. Patacamaya, Bol., 39: I-10. Riera, S., Mathews, D.H. and Lopez, J., 1972. Finura de1 pelo de alpacas y llamas. (Fineness of the alpaca and llama fiber). In: Memorias I Reunidn National de Investigadores en Ganaderia, Minist. Agric. y Ganaderia, La Paz, Bolivia, pp. 131-135. Rodriguez, T., 1981. Importancia de la influencia de factores ambientales sobre algunos caracteres de producci6n de came y lana en llamas. (Influence of environmental factors on meat and fiber production traits of llamas). Tesis Mag. Sci., Especialidad Ganaderia, Colegio Postgraduados Chapingo, Mexico, 127 pp. Ruiz de Castilia, M.N. and Olaguibel, 0.0.. 1991. Estudio de1 rendimiento y de las caracteristicas fisicas m&s importantes de la tibra en alpacas y llamas de color. (Yield and important physical traits of alpaca and llama colored fibers). Universidad San Antonio Abad, Cusco, Peru, Vol. I, pp. 19-69. SAS, 1987. SAS Institute Inc. SAS/STAT. Guide for personal computers, Version 6 Edition. Gary, NC: SAS Institute Inc., 1028 pp. Snedecor, G.W. and Cochran, W.G., 1967. Statistical Methods. 6th edition, Iowa State University Press, Ames, IA, 593 pp. Telleria, P.W., 1973. Estudio sobre algunas caracteristicas fisicas y quimicas de la tibra de llama. (Physical and chemical characteristics of the llama fiber). Tesis Ing. Agric., Universidad Mayor de San Simon, Cochabamba, Bolivia, 57 pp. Von Bergen, W., 1963. Wool Handbook. Vol. I, 3rd edition, Interscience Publishers, John Willey and Sons, New York and London, 800 pp.
Influence of effects on quality traits and relationships between traits of the llama fleece Z. Martinez a, L.C. Iniguez b7*, T. Rodriguez a ’ Bolivian Institute for Agricultural Technology, P.O. Box 8452, La Paz, Bolivia b University of Wisconsin-Madison, IAP, 240 Ag Hall, I450 Linden Dr., Madison, WI 53706-1562.
USA
Accepted 3 July 1996
Abstract Differences owing to age, sex and coat color on fleece traits, and relationships between traits, were investigated in fiber samples of llama fleece. Fiber samples were obtained from five fleece regions of 143 llamas: withers; shoulder; ribs; loin-rump and thigh. The fleece composition was heterogenous and consisted of different proportions of unmedullated (20.2%). fragmented med (36.7%). continuous med (39.4%), and kemp (3.7%) fibers. Average diameter, diameter of coarse fibers, diameter of fine fibers, medullation percentage, average length, undercoat length, guard hair length, clean fleece yields and crimps per 2.54cm averaged 31.6p,m, 40.8bm, 2.5.5l.t.m, 43.1%, KOlcm, 8.34cm. 6.67cm, 82.3% and 6.1 crimps, respectively. Age was the most important differentiating factor (P < 0.05) for all traits. Medullation percentage and average diameter significantly increased with the age of the animal. The fleece of two-year-old llamas was the finest, averaging a similar diameter and medullation (25.5 pm and 27.5%) to that of Medium Adult alpaca fiber. Average diameter was significantly associated with medullation percentage (r = 0.78). It also appeared that the degree of medullation induced important changes in fiber diameter, determining larger diameters as the proportion of medullated fibers increased at a linear change rate of b = 0.195 km per unit of percentage of medullation (P < 0.01). Diameters of finer unmedullated and fragmented med fibers were highly correlated to coarse continuous med fibers (0.60 and 0.74, respectively); thus animals having finer undercoats also would tend to have finer guard hairs. Fiber lengths and crimps per 2.54 cm decreased with age (P < 0.01). Although of a magnitude with no practical implications, differences owing to sex (P < 0.01) were found on diameter of coarse fibers, undercoat length, medullation percentage, clean fleece yields and crimps per 2.54cm. The coat color was a factor of differences (P < 0.01) for medullation percentage. Colored fleeces were less medullated than white fleeces (36 versus 47%, respectively). Relative to the five sampled regions, samples from withers and ribs were more representative because of their better homogeneity (lower variation coefficients) and degree of association with the mean of all sampled regions. 0 1997 Elsevier Science B.V. Keywords:
Llama; fibers; Fleece quality; Fleece medullation; Fiber diameter
1. Introduction
Corresponding author. Fax.: [email protected] l
608 262 8852: E-mail:
00921~4488/97/$15.00 Published by Elsevier Science B.V PII SO921-4488(96)00925-X
The largest population of llamas, consisting of about two million head, is located in the Andean regions of Bolivia at elevations of 3800m above sea
204
2 Martinez et al./Small
Ruminant Research 24 (1997) 203-212
level and higher. In these regions, llamas contribute substantially to the economy of marginal production systems in a range of extreme environments that limit the development of other types of livestock. Llamas are raised primarily to produce meat while the production of fibers is secondary and destined mainly to fulfll the needs of the producer’s family, in particular for the elaboration of clothes, ropes and bags. The fleece of llamas in contrast to that of alpacas, is lighter, and its fibers coarser and more heterogeneous (Telleria, 1973). These characteristics have prevented wider utilization of llama fibers by the textile industry. New industrialized machines that can dehair the llama fleece have been developed, thus permitting direct inclusion of the finer fibers in textile tops and offering promising prospects for llama producers. Llama populations are unselected and show wide variability in many fiber production traits. Little is known about the nature of this variability, particularly for quality traits of the fleece related to industrial acceptability. This study was designed to identify (1) factors affecting quality traits of the llama fleece, particularly those occurring during the production life cycle, and (2) relationships among fleece traits. 2. Materials and methods Fleece samples from 143 llamas, 60 males and 83 females, were obtained from the flock of llamas of the Bolivian Institute for Agriculture Technology (IBTA), at the Patacamaya Research Station (3800 m altitude), La Paz, Bolivia. Animals ranged from two to eight years of age and their coat colors were classified as completely white, completely colored, and mixed. Animals were maintained under similar management based on open range grazing from 0800 to 1630 with free access to water, and confinement in open corrals during the night. Mating and lambing seasons overlapped from mid-December to midMarch. Animals were shorn first at 21-22 months of age, and thereafter annually. Thus, in two-year-olds, the growth period of the fleece corresponded to the age of the animals, while in older animals the shorn fleeces represented one year’s growth. Shearing occurred in October, at the end of the dry season.
Birthdates, liveweights and fleece weights for each animal were recorded regularly. Fiber samples, each weighing 60-lOOg, were taken for analysis at shearing from tive fleece regions of a given animal. The regions were: withers (W), shoulder (S), ribs (R), loin-rump (LR) and thigh (T) (Fig. 1). 2. I. Laboratory analysis Fiber diameter was obtained by microprojection, according to ASTM (1991a) standards. A sample size of n = 300 individual fibers per sample was determined to provide a 95% confidence limit not greater than 0.7 units of the mean (Snedecor and Co&ran, 1967). Because of the great variation in types of fiber in each sample, individual projected fibers were classified according to presence of medulla (ASTM, 1991b) as: unmedullated, fragmented med (with fragmented and interrupted medulla), continuous med (those in which the diameter of continuous medulla was greater than 60% of the diameter of the fiber) and kemp (in which the diameter of the continuous medulla was less than or equal to 60% of the diameter of the fiber). Diameters of each type of fiber were measured. Two categories of fibers were also considered: fine (including unmedullated and fragmented med fibers) and coarse (including continuous med and kemp fibers). Average diameters of unmedullated (DUN), fragmented med (DFM), continuous med (DCM), kemp (DK), fine (DF) and coarse (DC) fibers, along with a general average including all fiber types (DA), were calculated for each sample. To facilitate medullation measurements of colored fibers, fiber specimens were treated for 24 h with H,O, prior to their microprojection.
Fig. 1.
Body regions from which fleece samples were obtained: withers (W), shoulder (S), ribs (R), loin-rump (LR)and thigh (T).
Z. Martinez et al./SmaN
Ruminant Research 24 (1997) 203-212
Proportions of unmedullated, fragmented med, continuous med and kemp fibers in a sample were obtained (UN%, PM%, CM%, and K%). Medullation (M%) was calculated as a percentage of continuous med and kemp fibers of all measured fibers in a sample. Length was taken from the external coat of coarser fibers or guard hairs (LG) and from the undercoat crimped fibers (LU), after dehairing a subsample by hand. Five measurements per subsample of fibers without stretching were made in each category. An average length per sample (LA) was obtained from LG and LU. The number of crimps per 2.54cm (NC) was measured with the Staple-Crimp Scale on 30 fibers randomly obtained per region per sample, without stretching or disturbing the crimps. Yields of clean fleece (Y%) were obtained for each sample on a subsample of 18-20 g of fibers that was washed with detergent and Na,CO, solutions, rinsed in water at 5O”C, dried, and weighed at approximately 16% relative humidity. 2.2. Statistical analysis Analysis was on averages of the different traits per region per animal. The observations among regions were not independent but actually repeated measurements of the same variable in a given animal, thus a test of independence using Mauchly’s sphericity criterion @AS, 1987) was conducted along with a within- and between-subjects univariate analysis. The basic linear model to test the influence of fixed effects in producing changes in each of the analyzed traits, included the following effects: age (i,: i = two,.., eight years), sex (j, j = 1: male and j = 2: female), white), k = 2 coat color (k,: k = 1 (completely (completely colored) and k = 3 (mixed)) and five regions as repeated measurements. Only interactions among regions and the other fixed effects were included in the model. Other interactions were pooled in the error term since their effect was non-significant. In analyzing fiber diameters the basic linear model was expanded to include medullation traits as covariates, in order to inspect whether fiber diameters changed as a consequence of different degrees of medullation.
205
Pairwise correlations among traits were obtained. In view of the influence of sample size on the statistical significance of the correlation coefficients, which could be regarded as significant even when the actual estimates of r approach zero, it was decided for discussion purposes that r > 0.55 reflected high association, 0.46 I r I 0.55 medium association, 0.25 I r I 0.45 a weak trend and r < 0.25 low association or independence. To determine a representative region of the five regions sampled in this study, effects owing to sex, age and coat color were first removed after correcting the data, without affecting the variation owing to regions. With the adjusted data, the homogeneity and degree of association of the regions were studied through ranks and functions of ranks. To analyze average homogeneity, CVs for each of the p regions (p = 1 (WI; p = 2 (S); p = 3 (R); p = 4 (LR); and p = 5 CT)) within a given trait q (q = 1,..9) were ordered by ranks (H,,), assigning lower ranks (one the lowest) to coefficients that reflected lower variability and five to the highest CV. Then all ranks of a particular region were added over all nine traits, obtaining a set of five sums (H,) per region. In this set lower sums expressed more homogeneity over all traits. To analyze the degree of association, within a trait (q) the set of five correlations between regions (p) with an average of all regions was ordered also by ranks (Ap4). Lower ranks (one the lowest) were assigned to higher correlations and higher ranks (five the highest) to lower correlations. A,,s of a given region (i) were added over all traits to obtain a set of five sums (A,). In this set, lower sums assigned to lower ranks expressed greater association of a given region with the average of all regions. H, and A, were finally added to obtain a global function of ranks flH,A) based on a set of five sums. This set was also ranked to decide the representativeness of the sampled regions.
3. Results and discussion 3. I. Quality components of the llama fleece Table 1 summarizes the analysis of the influence of effects on the studied traits, after removing the effect owing to correlated repeated measurements
Z. Martinez et al./SmaN
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Table 1 Effects of age, region, sex and coat color on quality traits of the fleece of llama Tests and sources of variation
X2 Significance
’
Tests within subjects Region Region X sex Region X age Region X color Tests between subjects Sex Age Color
Fleece
COmpOnentS
DA(pm)
DC(pm)
DF@m)
M%(%)
LU (cm)
LG(cm)
LAhd
Y%(s)
NC(n)
17.0
7.9 ns
18.0 *
29.9 *t
24.6 *
15.5 **
17.7 t*
8.7 ns
27.8 1.
t* tt tt
**
.*
.
ns tt
ns
ns
ns
ns ns ns
ns ns ns
** ** *t
ns *t
ns If
** t
** tt
ns
l
l
tt t. ns ns
ns ** ns
** ns ns ns
l
tt tt
l
*
tt tt ns
*
ns tt ns
ns ** ns **
ns ** * l
l
l
ns l
* *
*
ns
ns
a Sphericity chi-squared test for multicolinearity with 9 degrees of freedom; DA: average fiber diameter; DC: diameter of coarse fibers; DF: diameter of fine fibers; M%: medullation; LU: length of undercoat; LG: length of guard hairs; LA: length of all fibers; YW: clean fleece yield; NC: number (n) of crimps per 254cm. _ * : P < 0.05; ’ * : P < 0.01; ns: P > 0.05.
(regions). For all traits except for DC and Y%, the sphericity test revealed the presence of multicollinearity (P < O.Ol), which justified the utilization of tests of hypotheses for between-subjects and univariate tests for within-subjects effects. The main interest was in differences owing to age, sex and coat color. Nevertheless the within-subject analysis also revealed an important contribution of regions to the differences observed in most of the traits (P < 0.051, except in the case of M% (P > 0.05).
3.2. Diameter The averages and associated statistics of the different types of fibers are included in Table 2. Microscopic distinction of fibers yielded better estimates of diameters of fine and coarse fibers than those obtained in former macroscopic assessments (Riera, 1969; Tellen’a, 1973). The average diameter (31.6 pm for n = 214500; Table 2), was in the range of reports by Chivilchez (1959) Von Bergen (1963) and Castro (1988) and was slightly higher than averages reported by Onions (1962), Riera (1969) and Rodriguez (1981). Comparatively, alpaca average lower diameters in a range of 21-28 km ( Onions, 1962; Von Bergen, 1963; Flares, 1979; Espeztia,
1986). The average and SD estimates in this study were comparable to those of Alpaca Class A (adults with a lZmonths-growth fleece), according to ASTM (1991c) standards. Fine llama fibers, classified macroscopically as apparently unmedullated by Telleria (1973) yielded diameters (24.8 pm) comparable with those of fibers classified as fine in this study (25.5 km, with lowest and highest mean values of 18.1-37.7pm, respectively; Table 2). DUN averaged 22.7 p,rn (with mean values ranging from 16 to 32.4 pm; Table 2) within the range of Alpaca Class T (yearlings first shear, with lZmonths-growth fleece) in accordance with ASTM (1991c). Unmedullated and fragmented med fibers of alpaca varied from 15 to 20 pm and from 20 to 30 km, respectively; while kemps varied from 40 to 60 pm (Calle, 1982). Therefore, as opposed to the general belief, unmedullated fibers of llama measured in this study were not finer than unmedullated alpaca fibers. Age was an important cause of differences (P < 0.01) in diameter of fibers (Table 1) which, consistently tended to increase at older ages (Fig. 2 and Table 3). DA in two-year-old llamas were 26% lower than those in older animals (25.5 versus 32.2 brn, respectively, P < 0.01). The linear rate of increase of DA was 1.37 pm per year (P < 0.01).
Z. Martinez et al./Small
Ruminant Research 24 (1997) 203-212
207
Table 2 Mean diameters and lengths of llama fibers Average
Traits
E
Min
Max
SD
cv (%I
hi n2 *3
31.6 25.5 40.8 22.7
21.3 18.1 26.9 16.0
49.9 37.7 59.4 32.4
5.29 3.23 4.74 2.75
17 13 12 12
143 x 5 x 300 143 x 5 x 171 a 143 x 5 X 129 a 143X5X61a
5.44 9.00 7.22
2.86 5.12 4.12
15.22 21.28 17.86
1.82 2.49 2.08
33 28 29
143X5X5 143 x 5 x 5 143 x 5 x 10
5.01 8.34 6.67
2.86 5.12 4.12
10.96 13.52 11.79
1.18 1.31 1.16
23 16 17
126X5X5 126X5X5 126 X 5 X 10
Diameter (wrn)
AII fibers (DA) Fine fibers (DF) Coarse fibers (DC) Unmedullated fibers Lengths (cm) All observations
Undercoat (LU) Guard hairs (LG) All fibers (LA) Excluding a-year-old llamas
Undercoat (LU) Guard hairs (LG) All fibers (LA)
n,: number of llamas; n2: number of regions per llama; ns: exact number of fibers per sample or a average sample size based on distributions of fiber types per sample; SD: standard deviation; CV: coefficient of variation.
with age were also documented in the literature (Telleria, 1973; Riera et al., 1972; Rodriguez, 1981; Castro, 1988).
Changes in diameter were due mainly to changes in DUN, DFM and DCM, which increased (P < 0.05) with age at significant linear rates of 0.61, 0.80 and
Changes
Table 3 Estimates of effects contributing to differences in diameter and length of fibers, percentage of meduliation, clean fleece yield and fiber crimp numbers in llamas Main effects
nt
Sex Mates Females
DA (km)
DC (km)
DF(t.cm)
LG(cm)
LU(cm)
LA(cm)
MI(%)
Y%(%)
NC (n)
(60X 5) (83 X 5)
31.8 30.7
43.0a 39.4b
25.8 24.9
9.6 9.2
5.9a 5.3b
7.6 7.3
38.2 42.8
83.3a 81.8b
6.4a 6.0b
(17 X 5) (22 x 5) (25 x 5) (10x 5) (14 x 5) (20 X 5) (35 X 5)
25.5a 29.6b 30.6bc 31.3cd 34.Oe 33. lef 34.8e
37.3a 4O.lb 41.2c 41.7cd 42.4cde 41.7cdef 43.73
21.9a 24.5b 25.4c 24.9bcd 26.8e 26Sef 27.3e
13.9a 9.3b 8.7~ 9.3bd 7.6e 7.9ef 7.9ef
8.4a 5.6b 5.2~ 5.9bd 4.5e 4.9cef 5.Ocf
11.2a 7.4b 7.Oc 7.6bd 6.le 6.4ef 6.4ef
27.5a 36.9b 36.6bc 41 .Obcd 48.le 44.6def 48.7ef
82.8a 83.2ab 83.2abc 82.6abd 8 I .7de 83.0abcdf 81.2e
7.la 6.4b 6.2~ 6.2cd 6.0cde 6.1cdef 5.7g
(75 x 5) (38 x 5) (30 x 5)
31.7 31.4 30.7
4O.Oa 43.Ob 40.5a
25.1 25.6 25.2
9.2 9.0 9.6
5.6a 5.lb 6. lc
7.4a 7.Ob 7.9c
46.6a 35.5b 39.4c
82.2 82.9 82.5
6.2 6.3 6.2
Xn2
Age (years)
2 3 4 5 6 7 8 Coat color
Whole: White Colors Mixed
n,: number of llamas; n2: number of regions per llama; DA: average fiber diameter; DC: diameter of coarse fibers; DF: diameter of fine fibers; LG: length of guard hairs; LU: length of undercoat; LA: length of all fibers; M%: medullation; Y%: clean fleece yield; NC: number (n) of crimps per 2.54cm. ab,c,d,e,f,g estimates in a column within a given effect without a common letter differ (P < 0.05).
2. Martinez et al./Small
208
+ Medullatian
0
.I___. 2
__(___ 3
4
6
8
7
Medullation
percent
Ruminant Research 24 (1997) 203-212
r60
i-0 8
Age (yr) *
Average
diameter
-
Fig. 2. Changes of average diameter (DA) of fibers and percentage of medullation CM%) with the age of llamas.
0.83 km per year. Contrastingly, DK remained relatively unchanged (b = 0.096 pm per year; P > 0.05). Changes in diameter throughout the production lifetime deserve special attention because of its direct implications for the quality of the fleece, therefore it is suggested that future investigations focus on its physiological nature. Fig. 3 illustrates changes in the proportion of fine fibers with diameters less than 25 p,rn and fibers with diameters greater than or equal to 25 p,rn at different ages. In two-year-old animals, 48% of the fibers had diameters less than 25 km, this proportion was three times smaller at the age of three years, five times smaller at the age of four years and 12 times smaller in animals older than four years. Fibers with diameters greater than or equal to 25 p,rn increased correspondingly. This suggests the need to shear animals in groups of similar ages to obtain better returns; in particular groups of younger animals whose fleeces could be marketed at prices similar to those of alpaca. Coarse fibers of females were 3.6 pm finer than those of males (P < 0.05). Although differences owing to coat colors were unimportant (Table l), DUN, DFM, DCM and DK, according to the coat color categories, ranked white < mixed < colored (P < O.Ol>, suggesting that white fibers tended to be finer than colored. Reports on differences in the diameter of fibers owing to sex and coat colors (Telleria, 1973; Rodriguez, 1981) contrasted with others that did not confirm the results of this study (Amolds, 1964; Castro, 1988).
The diameters of finer fibers, DUN versus DFM, were highly correlated (r = 0.82) (Table 4). Similarly, a high association was found between diameters of finer and coarser fibers; DUN versus DCM (r = 0.60) and DFM versus DCM ( r = 0.741, respectively. Therefore, animals with finer undercoats also would have finer guard hairs. Diameters of the different types of analyzed fibers were not associated with DK. As it would be expected, a high negative association (r = -0.57; P < 0.01) was observed between DA and NC, because coarse med fibers are not likely to curl. Diameters and length of fibers evidenced weak or low association within the undercoat (DUN versus LU with r = -0.27; and DFM versus LU with r = -0.23, respectively), and within guard hairs (DCM versus LG with r = -0.24 and DK versus LG with r = -0.08, respectively) (Table 4). 3.3. Medullation UN%, FM%, CM% and K% accounted for 20.2, 36.7, 39.4 and 3.7%, respectively. Thus, 79.8% of the fibers in the fleece of llama consisted of medullated fibers. The average percentage medullation CM%), corresponding to the proportion of continuous med and kemp fibers, was 43.1%, with mean values ranging from 3.3 to 97%, SD = 21%, and CV = 49% (n = 2 14,500). Differences in medullation owing to age and color of the coat were important (P < 0.01; Table 1). The
% fibers loo-
Fiber diameter SO-
60.
I
45-49.9
y
Baa
40-44.9
y
35-39.9
”
20
./
0 I-l 2
3
4 Age (yr)
Fig. 3. Changes in the proportion of fine ( < 25 pm) and coarser fibers ( 2 25 pm) at different ages in llamas.
Z. Martinez et al. /Small
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Table 4 Correlation
coefficients
Traits
UN%
FM%
CM%
K%
DUN
DFhl
DCM
DK
LG
LU
UN% FM% CM% K% DUN DFM DCM DK LG LU
1
-0.15
- 0.78 - 0.48 1
- 0.47 - 0.37 0.56 1
-0.23 -0.12 0.29 0.08 1
- 0.07 - 0.23 0.22 0.02 0.82 1
0.15 - 0.27 0.06 - 0.03 0.60 0.74 1
-0.01 0.06 - 0.03 - 0.07 0.15 0.10 0.22 1
0.28 0.09 - 0.30 -0.22 -0.37 -0.36 -0.24 -0.08 1
0.27 0.08 - 0.28 - 0.20 - 0.27 - 0.23 -0.12 - 0.20 0.86 1
’ between components
1
corresponding
to tine and coarse fibers of the llama fleece (n = 715 pairs)
UN%: percentage of unmedullated fibers; FM%: percentage of fragmented med; CM%: percentage of continuous med; K%: percentage of kemps; DUN: diameter of unmedullated fibers; DFM: diameter of fragmented med; DCM: diameter of continuous med; DK: diameter of kemps; LG: length of guard hairs; LU: length of undercoat. a Levels of significance of correlation coefficients were: P > 0.05 if Irl< 0.08; P < 0.05 if 0.08 s Iris 0.09 and P < 0.01 if Irl > 0.09. Bold coefficients reflecting high association.
age-trend paralleled the pattern of diameters, as percentage medullation consistently increased at older ages (Fig. 2 and Table 3). The lowest M% (27.5%) was found in two-year-old animals which was different than M% at older ages (P < 0.01). Compared with two-year-old animals, M% increased from 33 to 34% at the age of three to four years and over 66% in animals older than four years. The rate of linear increase of M% was 3.2% per year (P < 0.01). The increase in medullation with age appeared to be directly caused by a net increase in CM% (b = 2.8% per year; P < 0.01) and K% (b = 0.4% per year; P < 0.05), than with changes in UN% (b = - 1.7% per year; P > 0.05) and FM% (b = - 1.6% per year; P > 0.05). While a low association was found between UN% and FM% (r = - 0.15>, CM% was highly correlated to K% (r = 0.56; Table 4), suggesting that fleeces high in continuous med would tend to be also high in kemp. It is interesting to contrast medullation across different species of camelids which, to some extent, may have a genetic basis: alpaca Suri 42.6% (Bellido, 19501, alpaca Huacaya 21%, one-year-old guanacoes 14% (Defosse et al., 19811, and vicuna 4.5% (Carpio and Solari, 1982). In addition, diameters of fibers also tend to decrease in the same order suggesting a positive relationship between diameter and degree of medullation. A high relationship between DA and M% (r = 0.78) was found in this study.
Moreover, the correlations of DA with UN%, FM%, CM% and K% were also high and in the expected direction: r = -0.59; r = -0.41; r = 0.77; and r = 0.57, respectively. It also appeared that the degree of medullation induced important changes in fiber diameter, determining larger average diameters as the proportion of medullated fibers increased at a linear rate of change of b = 0.195 km per unit of percentage medullation (P < O.Ol>, with intercept at 24 pm. Consistency in rates of change was observed within diameter components, as linear change rates of DUN ( - 0.032 km per unit of UN%, P < 0.01) and DFM (- 0.030 km per unit of FM%; P < 0.01) were negative, contrasting with positive linear rates of DCM (0.019 p,m per unit of DC%; P < 0.05) and DK (0.143 p,rn per unit of K%; P > 0.05). Weak correlations between %M and LA (r = - 0.3 1) were consistent with the estimates of Chavez (1991). The fleece of colored animals was found to possess less medullation than that of white animals (P < 0.05>, which is in agreement with Arnolds (1964) on llama and with Ruiz de Castilla and Olaguibel (1991) on alpacas. 3.4. Length offibers Average lengths of different types of fibers were included in Table 2. Undercoat fibers exhibited more variation than guard hairs (CV = 23% versus 16%).
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Age contributed to important differences (P < 0.01; Table 1) in the length of all fibers. The estimation of age effects (Table 3) revealed a reduction in the length of fibers at older ages: a trend also reported by Castro (1988) and Rodriguez (198 1). With an average LU ranging from 4.5 to 5.6cm and LA from 6.1 to 7.4 cm (Table 31, the fleece of lamas over two years old grown in one year could be utilized by the industry with no restrictions, however its medullation (36.6-48.7%; Table 3) and larger average diameter (29.6-34.8 pm; Table 3) could be limiting. A dehaired fleece or a fleece from animals with capacity to produce with lower M%, could permit its direct utilization in industrial processes opening important currently non-existent opportunities for llama producers. If continuous med and kemp fibers could be removed by dehairing, the remaining fleece, at the most, would have the diameter of fine fibers (25.5 Frn; Table 21, and be marketed as Medium Adult or Extra Fine alpaca fibers (ASTM, 199 lc). Contrastingly, the fleece of two-year-old animals has remarkable features. In fact, with LU 8.4 cm, DA 25.5 p.rn and M% 27.5% (Table 31, the fiber of these animals fit textile requirements well and could compete directly and advantageously with Medium Adult alpaca fibers (ASTM, 1991~). It is estimated that 200000-250000 head of two-year-old unshorn llamas, producing a yield of at least 1 kg per animal, would have the potential to contribute no less than 200 t of fine fiber if the animals were shorn. A strong association among LU and LG ( r = 0.86) was found. The color of the coat contributed to differences in LU and LA. LA and LU in white animals were larger than in colored (7.4 versus 7.0cm and 5.6 versus 5.1 cm, respectively; P < 0.05; Table 3). Although of a magnitude with no practical implications, sex differences were found for LU (P < 0.05; Table 3).
SD 3.4% and CV 4% (n = 715). This yield was lower than yields observed by Espeztia (1986) and Blanc0 (1980) in alpacas (86.7 and 88.8%, respectively). The average of 6.1 crimps per 2.54cm, with mean values ranging from 4 to 9.9 crimps, SD 0.89 crimps and CV 15% (n = 21,450), was comparable with counts obtained by Ruiz de Castilla and Olaguibel (1991) in alpacas (5.9 crimps per 2.54cm). Sex differences (P < 0.05; Tables 1 and 3) with no practical implications were found for both Y% and NC. NC declined at older ages (P < 0.01; Tables 1 and 3) possibly as a direct consequence of changes in medullation and fiber diameter of fibers. Crimps per 2.54cm in two-year-old llamas were higher than those in older animals (7.1 versus 6.1 crimps per 2.54cm in two-year-old and older llamas, respectively). Y% also reduced at older ages (P < 0.05; Tables 1 and 3), however, the magnitude of the changes had no practical implications.
Table 5 BLUE estimates of live weight classified by sex age and color
and fleece of weight
of llamas
Main effects
n
Fleece weights (kg)
Live weights (kg)
Sex Male Female
60 83
1.24a 1.03b
104.3a 91.3b
Age (years) 2 3 4 5 6 7 8
17 22 25 10 14 20 35
1.14 1.08 1.02 1.14 1.26 1.11 1.19
91.2a 98.6b 105.2b 105.4b 104.3b 101.9b 98.8b
3.5. Clean fleece yields and number of crimps per 2.54 cm
Coat color Completely white Completely colored Mixed
75 38 30
1.15a 1.04a 1.22ab
100.9 98.1 103.4
Clean fleece yields of llamas are known to be higher than those of many sheep breeds and most other fiber producing ruminants. Yields in this study averaged 82.3%, with a range from 70.7 to 89.7%,
n: number of llamas. a,b: estimates in a column within a given effect without a common letter differ (P < 0.05). Estimates in a column with no attached letters do not differ (P > 0.05).
Z. Martinez et al. /Small Ruminant Research 24 (1997) 203-212 Table 6 Ordering
P
of rank functions
by the degree of homogeneity
Regions
of a given region and its association
Withers (W) Shoulder(S) Ribs (R) Loin-Rump (LR) Thigh (T)
with the average of all sampled regions
Rank functions Homogeneity
1 2 3 4 5
211
H,. 23.5 19 28 29.5 35
Global
Association R 2 1 3 4 5
A,. 19 34.5 16.5 38.5 26.5
H,. and A,. sums of ranks over all q (q = L.9) fleece traits concerning association (A) with the average of all sampled p = 5 regions, respectively. AH,A) is the total sum of H,. and A,.
3.6. Liveweights and fleece weights All animals were in excellent body condition at shearing. Estimates of sex, age and coat color effects on liveweights and fleece weights have been included in Table 5. Average weight of two-year-old llamas (91.2 kg) was lower (P < 0.01) than that of older animals. Fleece weights were similar across ages (P > 0.05) and averaged 1.11 kg (SD = 0.30 kg and CV = 27%) in agreement with the estimate of Rodriguez (1981). Liveweights were uncorrelated to DA and M% ( r = 0.15 and r = - 0.09, respectively). Fleece weights were also uncorrelated to DA and M% (r = 0.008 and r = - 0.05, respectively). There was a weak association between fleece weights and liveweights (r = 0.42). 3.7. Degrees of representativeness among sampled regions Table 6 summarizes results concerning measurements of homogeneity and association to identify degrees of representativeness among the sampled regions. Over all traits regions ranked S > W > R > LR > T on the basis of their degree of homogeneity, i.e. having lower CVs. Regions, which on average were more correlated with an average of all sampled regions, ranked R > W > T > S > LR, according to their degree of association. Based on these results, the global function (Table 6) that takes into account measurements of homogeneity and association, suggested that W and R were more representative than the other sampled
Ranks
flH,A)
Ranks
2 4 1 5 3
42.5 53.5 44.5 68 61.5
1 3 2 5 4
the homogeneity
(H) of a given region
p and its degree of
fleece regions. Between these two suitable positions, R is likely to be the best because of its easy access for sampling. Considering that the whole fleece was not sampled, the average of all sampled regions does not correspond to the true average of the fleece. Thus, these results should be carefully interpreted in view of the fact that they do not apply to the whole fleece.
4. Conclusions The fleece of llamas consists of a mix of heterogeneous types of fibers ranging from unmedullated to kemp. Diameter and medullation increase in older animals affecting the industrial quality of the fleece, therefore shearing should be organized in similar age groups, so that the fleece of two-year-old animals could be directly marketed with competitive prices, similar to those of Medium Adult Alpaca fibers. The results suggest that the medullation condition is not only positively associated with diameter of fibers, but also causes changes in the diameter of fibers determining larger diameters as the proportion of medullated fibers, particularly of continuous med and kemp fibers, increases.
References ASTM, 199la. Annual Book of ASTM Standards. Desig. D213090 Standard Test Method for Diameter of Wool and Other Animal Standard Fibers by Microprojection. ASTM, Philadelphia, PA, Vol. 7 (01). pp. 581-589.
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ASTM, 1991b. Annual Book of ASTM Standards. Desig. D296889. Standard Test Method for Med and Kemp Fibers in Wool and Other Animal Fibers by Microprojection. ASTM, Philadelphia, PA, Vol 7 (01). pp. 809-81 I. ASTM, 1991c. Annual Book of ASTM Standards. Desig. D225285 (Reapproved 1991). Standard Specification for Fineness of Types of Alpaca. ASTM, Philadelphia, PA, Vol. 07 (011, pp. 601-602. Amolds, I.C., 1964. Algunas caracteristicas fisicas de la tibras de llama. (Some physical characteristics of the llama fiber). Tesis Ing. Agr., Universidad Catolica, Santiago, Chile, 55 pp. Bellido, N.J., 1950. Estudios comparatives de 10s caractems fisicos de ianas y de las producciones piliferas de 10s Cam&lidos Americanos: alpacas. (Comparative studies of fiber and fiber production traits in the American Camelids: alpacas). Bol. Ganaderia, Minist. Agric., Lima, Peru, 3(7): 66-77. Blanco, V.M., 1980. Peso vivo, peso vellon y rendimiento de vell6n de alpacas de la C.A.P. Huaycho Ltda. (Body weight, and fleece weight and yield in alpacas from C.A.P. Huaycho Ltd.). Tesis Med. Vet. Zoo]., Universidad Tecnica de1 Altipiano, Puno, Peru, 36 pp. Calle, E.R., 1982. Production y Mejoramiento de Alpacas. (Production and breeding of alpacas). Fondo de Libra, Banco Agrario, Lima, Peru, 334 pp. Carpio, P.M. and Solari, Z., 1982. Diametro de la tibra en el velldn de la vicutia (Fiber diameter in the vicuna fleece). In: Informes de Trabajos de lnvestigacidn en Vicuiias, Universidad National Agraria, Programa de Ovinos y Cam6lidos Americanos. La Molina, Peru, Vol. I, pp. 54-105. Castro, F., 1988. Analisis de1 velldn comercial de 10s camehdos: alpaca y llama. (Analysis of the commercial fleece of llama and alpaca). Tesis Ing. Agric., Universidad Mayor de San Sim6n. Cochabamba, Bolivia, 79 pp. Chavez, J.F., 1991. Mejoramiento Genetico de alpacas y llamas. (Genetic improvement of alpacas and llamas). In: S. Femartdez Baca (Editor), Avarices y Perspectivas de1 Conocimiento de 10s Camelidos Sudamericanos. FAO, 172 pp. Chivilchez, J., 1959. Estudio Biometrico y estructural de la lana de auquenidos (alpaca, llama y vicuha). (Structural and biometric study of alpaca, llama and vicuna fiber). Rev. Patronato Biol. Anim., 2(4): 355-421. Defosse, A.M., Garrido, J.S., Laporte, O.J. and Duga, L., 1981. Cria de guanacos en cautividad, variation de su crecimiento y cahdad de su lana. (Raising guanacos in captivity; variations in fiber growth and quality). Centro Patagonico, Argentina, No. 45, 17 pp.
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