Production performance, repeatability and heritability estimates
for live weight, ¯eece weight and ®ber characteristics
of alpacas in New Zealand
T. Wuliji
*, G.H. Davis, K.G. Dodds, P.R. Turner, R.N. Andrews, G.D. Bruce
AgResearch Invermay Agricultural Centre, P.B. 50034, Mosgiel, New Zealand
Received 2 June 1999; accepted 31 December 1999
Abstract
The production performance, repeatability and heritability estimates for live weight, ¯eece weight and ®ber characteristics of alpacas farmed in the South Island of New Zealand are reported. Male alpacas produced heavier ¯eeces (p<0.001) than females, but with relatively similar ®ber diameter. Mean (S.E.) shearing weight, greasy ¯eece weight (GFW), clean ¯eece weight (CFW), yield, staple length (SL), resistance to compression (RtC) and ®ber diameter (FD) in adults were 68.0 kg (1.0), 2.16 kg (0.06), 2.03 kg (0.06), 93.6% (0.4), 9.9 cm (0.2), 5.3 kPa (0.1) and 31.9mm (0.5), respectively. These means in tuis were 68.1 kg (1.9), 3.02 kg (0.20), 2.94 kg (0.27), 92.2% (0.4), 12.2 cm (0.3), 4.8 kPa (0.1) and 30.5mm (0.9), respectively. The corresponding measurements in crias were 40.5 kg (1.1), 1.97 kg (0.07), 1.84 kg (0.07), 93.4% (0.3), 12.6 cm (0.2), 4.6 kPa (0.1) and 26.4mm (0.4), respectively. The birth weight (BWT) was 8.4 kg (0.1) and SS was 28.4 N/ktex (1.9) in crias. The seasonal variation of ®ber growth and ®ber diameter was small to moderate, with lowest values in the winter. Mid-side ¯eece site FD was highly correlated with other main sites sampled and shown to be appropriate as a standard sampling site. The phenotypic correlation between CFW and FD was 0.40 (p<0.001) and for ¯eece weight and shearing live weight was 0.47 in adult alpacas (p<0.001). Correlation coef®cients for GFW and CFW with FD and SL were highly positive (GFW with FD and SL: 0.32±0.45, 0.39±0.54; CFW with FD and SL: 0.37±0.46, 0.40±0.53) in both tui and cria ¯eeces. The heritabilities for BWT, summer weight, spring weight, GFW and CFW, yield, SL, RtC and FD were estimated as 0.63, 0.41, 0.99, 0.63, 0.68, 0.67, 0.57, 0.16, 0.69 and 0.73. Production performance and heritability estimates for these traits were markedly higher than that previously reported in South American camelids.#2000 Elsevier Science B.V. All rights reserved.
Keywords:Alpaca; Cria; Fleece characteristics; Coat color; Heritability
1. Introduction
The alpaca (Lama pacos), llama (L. glama), gua-naco (L. guanacoe) and vicuna (Vicugna vicugna) form the group known as the South American or New World camelidae. The alpaca is the most impor-tant ®ber producing member of this group. There are Small Ruminant Research 37 (2000) 189±201
*Corresponding author. Present address: Agricultural Research
and Extension, Langston University, P.O. Box 730, Langston, OK 73050, USA. Tel.:1-405-466-3836/35; fax:1-405-466-3138.
E-mail address: [email protected] (T. Wuliji)
two breeds of alpacas, known as huacaya and suri, with the former having a crimpy and bulky ¯eece, while suri grows a straight and compact ¯eece. Alpaca ®bers are lightweight and strong, with high luster and insulation properties that are desired by textile pro-cessors. The 3 million alpacas in Peru produce about 90% of the world camelid ®ber production (Pumayalla and Leyva, 1988). The status and distribution of llamas and alpacas (Novoa and Wheeler, 1984), and production of alpacas in the Andes (Fernandez-Baca, 1975) have been reviewed comprehensively. Although camelids were regarded as being exclusively adapted to the highland environments of the Altiplano, intro-duction to various other regions has been highly successful. Genetic resources and husbandry practices in South American camelid species have been documented in some detail (Calle-Escobar, 1984; Hoffman and Fowler, 1995). However there is little information on various productive traits, including birth weight (BWT), mature live weight, ¯eece weight, and especially ®ber characteristics, in the literature. This information, including heritability esti-mates, is keenly sought after by new camelid growers. In recent years, there has been growing interest outside South America, particularly in New Zealand, Austra-lia and North America, in alpacas as ®ber producers and pets.
AgResearch (then MAF Technology) of New Zeal-and imported a herd of 100 alpacas from Chile in 1989 and these were farmed separately at the Tara Hills High Country Research Station, Omarama and a nearby private property at Lowburn. The ®rst alpacas introduced in New Zealand were all of huacaya breed. The aim was to establish a new specialty ®ber industry. A programme to study farmed alpaca ®ber production commenced in 1989. The speci®c objectives were to monitor the ¯eece weight, seasonality of ®ber growth, the ¯eece weight components, and their relative importance in selection for ®ber production. Prelimin-ary results of growth, reproduction and ¯eece produc-tion have been reported previously (Davis et al., 1991; Wuliji et al., 1992). This paper reports the production performance and repeatability in liveweight, ¯eece weight and ®ber characteristics in adult alpaca herds for six production years (1989±1994). The production performance, correlation among traits, and heritabil-ities for these traits were also estimated using data available from crias within 17 sire groups.
2. Materials and methods
2.1. Animal management
Alpacas were grazed in paddocks within a farmlet on irrigated plains at an altitude of 490 m above sea level at Tara Hills High Country Station (Latitude 448320
S, Longitude 1698540
E) and a nearby Lowburn property with pastures of predominantly perennial ryegrass and white clover. The region is located in a semi-arid highland, with an average annual rain fall of 520 mm (range 380±770 mm), a mean daily temperature on the ¯ats of 15.88C in mid summer and 1.38C in mid winter, and an average 10 days of snowfall and 160 ground frosts per year. In winter, they were supplemented with either lucerne hay or concentrate pellets. The alpacas were grazed separately as males, females, tuis (1± 11/2 year old alpacas) and weaned crias. Similar management was practised on both properties. Joining was carried out in spring and autumn each year and therefore parturition occurred in these sea-sons in the following year. The adult alpacas were a mixture of 2±4 year olds (as determined by visual inspection) at importation in 1989 and in each sub-sequent year a few young replacements were retained for the breeding herd. Crias were weaned at 6±8 months of age and ®rst shorn at 7±12 months of age in spring (October).
2.2. Shearing and ¯eece classing
2.3. Recording and measurements
The birth date, pedigree, birth weight and weaning weight (WWT) were recorded for crias. Other live weight measurements coincided with seasons: mid summer (SuLW) in January, autumn (ALW) in April, and spring (SLW) in October (at shearing). Greasy ¯eece weight (GFW) was recorded at each shearing. Fleece yield (%), clean ¯eece weight (CFW), mean ®ber diameter (FD), staple length (SL), staple strength (SS), point of break (POB) and resistance to compres-sion (RtC) were also measured. FD was measured by three procedures for adult ¯eeces Ð optical ®ber diameter analyser (OFD, SGS Ltd), sonic ®neness tester (SFD) and air¯ow apparatus (AFD, IWTO-6). FD of tui and cria ¯eeces was only measured by optical ®ber diameter analyser (IWTO).
2.4. Seasonal ®ber growth rate and ®ber sampling site
Alpacas at Tara Hills were monitored for seasonal ®ber growth clipping a de®ned midside patch (12 cm12 cm) on the right side at three monthly intervals as described by Wuliji (1993a). Each patch was clipped using small animal clippers (comb Size 30) and expressed as clean ®ber growth per area (in mg/day/cm2), and mean ®ber diameter (AFD) was determined for each patch.
A random subgroup of alpacas (two males and 12 females) was clipped on 12 different body sites at the 1990 shearing to investigate FD variation over the body and to determine the most representative sam-pling site.
2.5. Statistical analysis
Data for crias and tuis were analyzed separately by least-squares analysis of variance. Models included year, sex, location, coat color and date of birth. The models for the ¯eece measurements in tuis also included a term to indicate whether or not the animal had been shorn as a cria, to account for a group of crias left unshorn in 1990. For adults, the data were ana-lyzed by residual maximum likelihood (REML) with model terms as for crias except the omission of birth date and the inclusion of individual animal as a random effect, and effects not involving year were
tested against the mean square for this term. Two factor interactions (excluding coat color interactions for liveweights) were checked, and discarded if not signi®cant. Interactions that were retained were: sex by year for adult yield, tui yield and tui staple length; coat color by year for adult RtC; birth date by year for tui SLW and ¯eece weight; and birth date by cria shearing status for tui ¯eece weight. Adult seasonal data were analyzed by REML with individual as a random effect and the year by season by sex interac-tion as a ®xed effect. Heritabilities were estimated by animal model REML (Johnson and Thompson, 1995) with a model as given earlier for crias, but with the inclusion of pedigree relationships. There were 17 sires represented among those with known sires.
3. Results
3.1. Adult alpacas
The live weight, ¯eece weight and ¯eece character-istics of adult alpacas are presented in Table 1. SLW signi®cantly increased from the year of importation, 1989, to 1994. ALWs were consistently heavier than SLWs. There were a few ¯eece weight differences found between years where the ¯eeces represented 12 months' growth (1990±1994), but no obvious trend. Yield was signi®cantly higher (p<0.01) for ¯eeces in 1991 and 1994 than in other years. Differences in SL between years were generally small. RtC increased slightly from 1990±1994 (p<0.05). OFD increased signi®cantly between years (p<0.05), except for a non-signi®cant drop from 1991 to 1992. The cumu-lative distribution of mean FD in adult alpacas is illustrated in Fig. 1. The difference between year 1989 (soon after importation) and 1990 (®rst shearing in NZ) was 6.5mm, and over subsequent years FD increased by a further 0.9mm per year.
alpacas appeared to be ®nest and black & white coarsest, differences were not signi®cant. Black alpa-cas had a lower yield than other colors except gray and black & white, while lighter colors tended to have higher RtC (in all years). SS and POB were measured only in 1989 ¯eeces and showed that alpaca ®bers are generally of a high strength with little variation among sexes or coat colors, and further measurement was not pursued in subsequent years.
The body region FD variation is illustrated in Fig. 2. Fleece FD tended to coarsen from the midside towards the shoulder points and towards the rump, and from
the top of the back line to the belly, limbs and neck. A midside ¯eece area centered over the 6±7th ribs had a high correlation (r>0.8) with the eight other main body sites, apart from the sites above the legs, for which the correlations averaged 0.6. The midside site also had a similar value (23.4mm) to the mean of the eight other main body sites (23.7mm). The FD of neck ¯eece (24.3mm) was similar to that of the lower shoulder region (24.4mm) but the FD was shorter. The FDs of upper front and hind leg sites were signi®cantly coarser (29.2±29.6mm) than for other parts. Therefore partitioning the shorn ¯eece into three Table 1
Best linear unbiased estimates for live weight, ¯eece weight and ®ber characteristics of adult alpacas (1989±1994)a
No. SulW
aSuLW: summer liveweight; ALW: autumn liveweight; SLW: spring liveweight; GFW: greasy ¯eece weight; CFW: clean ¯eece weight;
SL: staple length; SS: staple strength; POB: point of break; RtC: resistance to compression; OFD: optical ®ber diameter; SFD: sonic ®ber diameter; AFD: air¯ow ®ber diameter; means with different letters a, b, c, d and e are signi®cantly (p<0.05) different (shown only if the effect was signi®cant atp<0.10).
bGFW and CFW in 1989 were for 7±12 months of growth. cSS and POB was measured only for 1989 ¯eeces.
Fig. 1. Fiber diameter variation (cumulative % of total adults) in years (1989±1994).
categories: main, neck and oddments (which includes belly, head, britch, legs and tail) seems appropriate. The subsequent sampling of the different sites in 1990 and 1991 showed a similar result.
Changes in clean ®ber growth rate (mg/cm2/day) and FD between seasons are shown in Fig. 3. Fiber growth rate was signi®cantly (p<0.001) higher for males than females throughout the 2 years, but the difference in FD was not signi®cant. Fiber growth rate and FD were lower in winter than other times of the year.
Correlation coef®cients among ¯eece characteris-tics and CFW are shown in Table 2. FD measurement by OFD was in close agreement with SFD (r0.95) and AFD (r0.97) with the latter two means being slightly lower than OFD. SS was moderately and positively correlated with FD but negatively with RtC and SL, while POB was moderate and positively correlated with RtC and SL, but moderately negatively correlated with SS. All ®ber characteristics were positively correlated with CFW, except SS, which
was negatively correlated. All other phenotypic cor-relations were minor.
The estimated repeatability of production traits in adult alpacas across 5 years of measurement is pre-sented in Table 3. Live weight, ¯eece weight, SL and FD were highly repeatable, while yield and RtC were moderately repeatable. The most repeatable live weight, ¯eece weight and ®ber characteristics were ALW (0.80), GFW (0.92) and FD (0.92; OFD or AFD), respectively.
3.2. Tuis and crias
sexes except that females had lower yield in 1 year. There were some year and color effects on yield, SL and RtC.
Live weight, ¯eece weight and ®ber characteristics measured in crias are presented in Table 5. Males were signi®cantly heavier than females at birth (0.5 kg) and this difference was maintained at SuLW and SLW. Male crias produced signi®cantly higher ¯eece weights than females (p<0.01), however there was no difference in yield and ®ber characteristics. The comparison between birth years shows some differ-ences for live weight, yield and ®ber characteristics. A signi®cant (p<0.01) difference was found for FD between birth years, with an increase averaging 0.8mm per year. There was no year effect on SS. Some color effects were found for liveweights, SL and RtC.
Phenotypic correlation coef®cients for GFW and CFW with FD and SL were highly positive (p<0.01) in crias and tuis (Table 6). In crias, GFW and CFW were also positively correlated with SLW (p<0.01), and FD
was signi®cantly correlated with RtC (p<0.01). How-ever, correlations between corresponding traits for crias and tuis (not shown) were mostly not signi®cant, except for RtC (0.33, p<0.01) and SLW (0.26,
p<0.05). The heritability (h2) estimates for live weight, ¯eece weight and ®ber characteristics are presented in Table 7. The h2estimate was high for live weight, ¯eece weight, yield, SL, RtC and FD. Only SS had a lowh2estimate. However, the standard errors of some of these estimates were also high due to the small sample size.
4. Discussion
The birth weights were similar to, but other live weights of both tuis and crias were greater than those documented in the South American literature. Bus-tinza et al. (1988) found a mean BWT of 8.4 kg for alpacas in Peru although there was signi®cant varia-tion among dam age groups. Fernandez-Baca (1971)
Table 3
Repeatability (r) of live weights, ¯eece weights and ®ber characteristics in adult alpacas (1990±1994)a
SuLW ALW SLW GFW CFW Yield SL OFD AFD RtC
R 0.66 0.80 0.66 0.92 0.91 0.36 0.76 0.92 0.92 0.54
S.E. 0.04 0.02 0.04 0.01 0.01 0.05 0.03 0.01 0.02 0.05
aSuLW: summer liveweight; ALW: autumn liveweight; SLW: spring liveweight; GFW: greasy ¯eece weight; CFW: clean ¯eece weight;
SL: staple length; RtC: resistance to compression; FD: ®ber diameter. Table 2
Correlations (adjusted for sex, year and location) between the main ¯eece characteristics in adult alpacasa
OFD SFD AFD RtC SL SS POB CFW
Yield 0.20*** 0.20** 0.16** 0.08 0.13** 0.04 ÿ0.02 0.22***
OFD 0.95*** 0.95*** 0.05 0.11* 0.34*** ÿ0.15 0.40***
SFD 0.97*** ÿ0.09 0.03 0.38*** ÿ0.21* 0.24***
AFD 0.03 0.09 0.37*** ÿ0.20 0.39***
RtC ÿ0.05 ÿ0.32** 0.29** 0.16***
SL ÿ0.62*** 0.48*** 0.52***
SS ÿ0.29** ÿ0.44***
POB 0.44***
aCFW: clean ¯eece weight; SL: staple length; SS: staple strength; POB: point of break; RtC: resistance to compression; OFD: optical ®ber
diameter; SFD: sonic ®ber diameter; AFD: air¯ow ®ber diameter.
*p<0.05. **p<0.01. ***p<0.001.
quoted a BWT of 9 kg and 9 month weight of 29 kg with a small difference between sexes. A previous study in New Zealand alpacas reported no difference between sexes and locations for BWT and other weights (Davis et al., 1991). The SLW of females was higher than males in tuis, which could be accounted for by the late gestation period of these animals rather than sex differences per se. Marshall et al. (1981) reported that young females, raised for breeding on improved pastures in Peru, reach 40 kg at about 10 months old, however the improved nutrition dramatically increased FD (7mm) in tuis and crias.
The ¯eece weights of both tui and cria were greater than those in South America (Calle-Escobar, 1984; Castellaro et al., 1998). The highest quality ®ber, as indicated by low FD, was produced from young animals, especially crias. Separating these ¯eeces from those of older animals may substantially increase ®ber values. RtC values of crias were lower than that
of adult alpacas, which may re¯ect the ®ner FD and longer SL of young animals. The FDs measured for crias and adults were 26.5 and 32.0mm (1991), respec-tively, compared with 17.7 and 27.5mm reported by Flores and Gallegos (1979) for corresponding age groups in Peru.
The liveweight difference between years probably re¯ected the improved nutrition in the new farming environment, but because age and year effects were confounded in the imported animals the possibility of some age effect on the observed liveweight increases cannot be discounted. Females were signi®cantly heavier than males as adults and tuis, but differences are confounded by the stage of pregnancy in many breeding females. The liveweights of adult alpacas were greater than those in Chile but ¯eece weights were similar. These results agree with initial observa-tions by Wuliji et al. (1992). The mature weight at 6 years of age was 65 kg in female alpacas in Peru, and Table 4
Least squares means for live weight, ¯eece weights and ®ber traits in tuis (1991±1994)a
No. SLW (kg) GFW (kg) CFW (kg) Yield (%) SL (cm) RtC (kPa)b FD (mm)
Mean 126 68.1 3.02 2.94 92.2 12.2 4.8 30.5
S.E. ± 1.9 0.20 0.27 0.4 0.3 0.1 0.9
Sex
Female 68 70.7 b 2.79 a 2.64 a 92.0 11.6 a 4.8 30.5
Male 58 65.4 a 3.25 b 3.23 b 92.5 12.8 b 4.9 30.5
S.E.D. ± 1.8 0.13 0.28 0.5 0.3 0.1 0.9
Production year
1991 41 68.9 2.82 2.68 94.9 b 12.8 4.0 a 28.7
1992 29 68.3 2.74 2.58 90.6 a 11.4 a 4.6 b 30.1
1993 35 67.0 3.35 3.21 91.1 a 12.7 b 4.8 b 32.2
1994 21 ± 3.17 3.27 92.3 ab 12.0 ab 5.9 c 30.9
S.E.D. ± 4.4 0.38 0.38 1.2 0.7 0.2 2.4
Coat color
W 28 73.2c 3.15 3.05 92.8 bc 13.3 b 5.5 e 29.8
B 12 61.8 a 2.99 2.99 94.1 c 11.5 a 4.6 bc 30.2
LBr 31 67.5 ab 3.11 3.04 92.5 bc 12.4 a 4.7 bc 30.7
DBr 27 68.0 abc 2.92 2.78 90.9 a 12.4 a 4.2 a 29.8
G 5 64.0 abc 3.03 2.94 90.8 ab 12.1 ab 5.2 cde 30.7
R 6 73.0 bc 2.82 2.71 91.9 abc 12.0 ab 5.4 de 28.3
BrW 9 66.0 ab 2.95 2.98 93.0 bc 11.3 a 4.7 bcd 32.5
BWh 8 71.0 abc 3.19 3.00 91.8 ab 12.6 ab 4.4 ab 31.8
S.E.D. ± 4.3 0.28 0.34 1.1 0.6 0.3 2.1
Table 6
Correlations (adjusted for sex, year, birth date and location) among the main ¯eece characteristics and spring live weight in crias and tuisa
Criab Tuib
CFW Yield FD SL RtC SLW CFW Yield FD SL RtC SLW
GFW 0.99*** 0.12 0.45*** 0.54*** ÿ0.04 0.32*** 0.99*** 0.01 0.32*** 0.39*** 0.08 ÿ0.06 CFW 0.22* 0.46*** 0.53*** ÿ0.07 0.28** 0.17 0.37*** 0.40*** 0.07 ÿ0.07
Yield 0.23** ÿ0.04 ÿ0.27* ÿ0.28** 0.25** 0.07 0.20* ÿ0.07
FD 0.14 ÿ0.28** 0.16 ÿ0.03 ÿ0.01 0.13
SL ÿ0.12 0.44*** 0.16 ÿ0.04
RtC 0.02 0.05
SLW
aSLW: spring liveweight; GFW: greasy ¯eece weight; CFW: clean ¯eece weight; SL: staple length; RtC: resistance to compression; FD:
®ber diameter.
bRefer Table 2 for the description of the signi®cant values indicated by the asterisks here.
Table 5
Least squares means for live weight, ¯eece weights and ®ber traits in crias (1990±1994)a
No. BWT
(kg)
SuW (kg)
SLW (kg)
GFW (kg)
CFW (kg)
Yield (%)
SL (cm)
SSb
(Nktex) FD (mm)
RtC (kPa/g)
Mean 235 8.4 22.6 40.5 1.97 1.84 93.4 12.6 28.4 26.4 4.6
S.E. 0.1 0.5 1.1 0.07 0.07 0.3 0.2 1.9 0.4 0.1
Sex
Female 101 8.2 a 22.4 40.1 1.85 a 1.73 a 93.4 12.3 a 28.2 26.6 4.6 Male 125 8.7 b 22.8 40.6 2.02 b 1.89 b 93.4 12.7 b 29.6 26.3 4.5
S.E.D. ± 0.2 0.6 1.4 0.07 0.06 0.4 0.2 1.5 0.4 0.1
Birth year
1990 57 7.9 20.8 a 40.4 1.92 1.79 92.1 11.7 a 24.6 a 4.3 a
1991 42 8.6 22.2 ab 41.1 1.78 1.72 96.6 12.8 b 25.3 a 4.2 a
1992 47 8.3 22.3 ab 41.5 1.96 1.81 92.2 13.7 b 30.9 26.3 ab ±
1993 34 9.0 24.6 b 38.4 2.13 1.98 92.6 12.5 ab 26.9 28.5 b 4.1 a
1994 47 8.5 23.1 b ± 1.88 1.76 93.4 12.0 a 27.3 b 5.7 b
S.E.D ± 0.3 1.2 2.9 0.20 0.19 1.0 0.5 3.6 1.1 0.1
Coat Color
W 54 8.6 22.2 bc 46.8 b 2.08 b 1.93 92.6 13.5 b 31.7 c 25.8 4.8 d B 9 8.9 23.6 abc 37.7 a 1.94 ab 1.83 94.2 12.0 a 29.2 abc 26.0 4.6 bc LBr 14 8.6 22.9 bc 38.7 a 1.84 a 1.73 93.9 12.3 a 26.2 ab 26.9 4.5 bc DBr 57 8.6 22.8 bc 38.7 a 1.80 a 1.68 92.7 12.5 a 26.6 ab 26.3 4.0 a G 44 7.5 21.0 ab 41.1 ab 1.88 ab 1.75 92.8 12.1 a 21.9 a 25.3 4.6 bcd R 13 8.2 19.1 a 41.8 ab 2.01 ab 1.92 93.1 12.7 ab 36.7 abc 25.9 5.1 d BrW 23 8.3 22.9 bc 37.6 a 2.05 ab 1.92 93.3 12.1 a 30.6 bc 26.9 4.7 cd BWh 8 8.8 26.2 c 40.3 a 1.86 ab 1.75 94.3 13.0 ab 28.3 abc 28.2 4.2 ab
S.E.D. ± 0.4 1.8 3.3 0.17 0.16 0.9 0.5 4.3 1.0 0.2
aMeans with different letters a, b, c, d and e are signi®cantly (p<0.05) different (shown only if the effect was signi®cant atp<0.10). bSS was measured for born 1992 and 1993 crias.
males were usually found to be heavier (Barreda et al., 1975). There was a large difference between early growth rates in this study compared with Peru (Calle-Escobar, 1984). Effects of environment and nutrition have been observed in Chile, by Raggi et al. (1994) with location differences in adult liveweight of up to 11 kg. Alpacas grazing on Mediterranean grasslands were reported to maintain a similar live weight as in the New Zealand environment (Castellero et al., 1998).
Annual ¯eece weight was relatively stable after being farmed in New Zealand. The SS was higher for alpaca ®bers relative to wool of the same micron, in agreement with other camelid ®bers (Iniguez et al., 1998). The lower RtC in alpaca ¯eeces than sheep wool (Wuliji et al., 1990) is a consequence of softer ®ber with less crimp. There are no comparative data published for RtC. The RtC in Merino wool is highly correlated with follicle curvature, ®ber crimp and con®guration, and ®ber diameter (Whiteley et al., 1978). The effect of these factors on RtC in alpacas is unknown. The major impurities of the ¯eece were vegetable matter and soil that was caught up in the ¯eece through their `dust bathing' habits. The alpaca ¯eece comprises wool and hair, and shearing should attempt to get the best separation of these. Wool ®ber covers the sides and the loin of the animal while hair ®ber covers the chest, belly, face and legs. It is also worthwhile noting that the weathered ¯eece tips and ultraviolet light damage of the ¯eece can be severe, especially if shearing intervals are extended too long.
Bustinza and Gallegos (1970); Gallegos and Avilla (1979); Condorena (1980) showed that, in general, ®ber production was in¯uenced by breed, sex and age. In their studies, GFW was highest at second shearing and was relatively stable (at about 2 kg per
head) until the eighth shearing. The GFW and CFW of alpacas in New Zealand was similar to that reported from South America (Calle-Escobar, 1984; Castellaro et al., 1998), with the same marked increase in second shearing GFW, CFW and SL. The yield was 10±20% higher than for alpacas studied in Chile (Castellaro et al., 1998) but moderately (3±7%) higher than other South American records (Pumayalla and Leyva, 1988). The alpaca ¯eece shows a higher yield than sheep's wool (Calle-Esco-bar, 1984) because of the lower grease content. The lower grease content is due to fewer sebaceous glands in the skin of alpacas.
A few signi®cant but small differences were dis-played among coat colors in young and adult alpacas. Some breeders claim that dark coats are softer and ®ner than white (Chamlee and Quigg, 1991) and that lesser medullation was found in colored ¯eeces than whites (Iniguez et al., 1998). We found white coats to have consistently higher RtC than other colors. How-ever, our results show no real evidence that any particular coat color is inferior to others for ®ber diameter and strength. Therefore selection for coat color is unlikely to affect ®ber production.
The FD of alpacas was considerably coarser in the New Zealand environment than in South America. Although these differences are likely to be mostly environmental, there may also be genetic factors involved. The FD measured for adults was 32.0mm in New Zealand (e.g., 1991) compared with 27.5mm reported by Flores and Gallegos (1979) in Peru. The similar FD changes in age groups were demonstrated with llamas in Southern Bolivia (Iniguez et al., 1998). Alpacas are known to grow more ®bers over 30mm as they age. In South America, Calle-Escobar (1984) reported an increase from 27.9 to 38.4mm in female alpacas differing in age by 13 years. Briosco (1963) Table 7
Estimated heritability (h2) for liveweight, ¯eece weights and ®ber traits in alpacas (1990±1994) compared with sheepa
BWT SuLW SLW GFW CFW Yield SL SS RtC FD
h2 0.63 0.41 0.99 0.63 0.68 0.67 0.57 0.16 0.69 0.73
S.E. 0.16 0.47 0.03 0.22 0.22 0.18 0.18 0.44 0.27 0.19
Sheeph2 0.13 0.33 0.48 0.34 0.37 0.48 0.54 0.23 0.65 0.51
aSheeph2from Wuliji et al. (1998); BWT: birth weight; SuLW: summer liveweight; SLW: spring liveweight; GFW: greasy ¯eece weight;
also showed that FD increased 10mm while SL decreased 4 cm in gelded alpacas from 5 years up to 15 years of age. Similar, but lesser, increases in FD of llama ¯eeces from 1 to 5 year olds (Iniguez et al., 1998) is intriguing, but is likely due to nutritional and environmental limitations at a high elevation (3600± 4600 m). It is also interesting to note that in our study, increases in ®ber diameter and length more than accounted for the increase in ¯eece weight. This suggests that more of the increase in ®ber growth in the better environment was partitioned to volume than to mass of ¯eece. This is consistent with the observa-tion that the medullaobserva-tion ratio in ¯eeces increased dramatically following their importation to NZ (Wuliji, 1993b).
FD measurements from various ¯eece sites indi-cated that the mid-side site was representative of the blanket region of the ¯eece (side and back) only. Alpaca neck ¯eece is too short to be mixed with the main ¯eece. In contrast, samples from the different body sites in sheep appear more homogeneous. There-fore, in alpacas belly and other extremities are of the poorest quality and should be separated from the blanket and necks at shearing.
The seasonal effect on ¯eece growth and FD was minor compared with that in wool from crossbred sheep (Wuliji et al., 1995). The ®ber growth and FD ¯uctuations mostly corresponded to the expected nutritional changes in pastures and only a moderate seasonality of ®ber growth was observed for alpacas (Wuliji, 1993a). This seasonal growth rate was in a descending order of summer, spring, autumn and winter. These results are supported by nutritional studies in camelids (Marshall et al., 1981; Newman and Paterson, 1994; Russel and Redden, 1997). Mar-shall et al. (1981) showed that improved nutrition (lucerne versus native rangeland in Peru) increased live weight and FD in adult alpacas (9 kg and 5mm, respectively). Newman and Paterson (1994) reported from the North Island of New Zealand that alpacas fed ad lib had 21% more ®ber growth than control alpacas fed at maintenance, and there was a difference of 25% between summer and winter on FD.
The major production and quality traits (GFW, CFW, SL and FD) appear to be highly repeatable in a stable environment as indicated by the repeatability estimates for annual measurements between 1990 and 1994.
Estimates of the heritability of live weight, ¯eece weight and ®ber traits in this study were higher than some earlier reports. Some heritability estimates (par-ticularly that for BWT) may have been in¯ated by maternal genetic effects, but our data set is too small to reliably distinguish direct and maternal genetic effects. Estimates were also higher than for the corre-sponding traits in crossbred wool sheep (Wuliji et al., 1998), except for SS. However they seem to be in agreement with the high repeatability estimates for these traits in adult alpacas. In other studies, Velasco (1980) estimated that heritabilities for live weight and ¯eece weight were 0.69 (0.2) and 0.35 (0.2) respectively. Bustinza et al. (1988) estimated the heritability for BWT as 0.34. Blackwell (1983) cited data of experiments at La Raya Station, which esti-mated the heritability of BWT at 0.53, weaning weight at 0.39, yearling body weight at 0.55±0.69, and ¯eece weight at 0.22±0.35. The phenotypic correlations among GFW, CFW, FD and SL were high in both crias and tuis. However, the correlation between traits measured as cria and tui were poor except for RtC. This re¯ects that the most dramatic change for many production traits occurs between the ®rst and second shearing.
It is considered that when alpacas are bred for ®ber production, selection should concentrate on high ¯eece weight and FD, and low FD and medullation. The emphasis on color depends on whether the com-modity or craft market is targeted. Color preference also differs between the ®ber and pet markets. Cross-breeding with vicunas should be explored as an option for reducing FD of alpacas in favorable environments such as New Zealand and Australia. Vicunas produce ®ber with a diameter of 12±13 microns, although ¯eece weights are very low. Early attempts at cross-breeding indicated that crosses had improved ®ber characteristics and the offspring adapted to domestic farming (Calle-Escobar, 1984). Carpio et al. (1990) reported FD of such a cross, called paco-vicuna, was in the range of 13±17mm, which is equivalent to that of cashmere ®ber.
5. Conclusion
America. The production performance of live weight, ¯eece weight and ¯eece characteristics was quanti®ed in alpacas and the repeatability in production perfor-mance and correlations between ®ber traits were established. Under New Zealand farming conditions, live weight was improved. However, ¯eece weights were similar and FD was considerably coarser, com-pared with reports for alpacas in South America. The heritabilities for these traits were estimated from progeny bred in New Zealand. Estimates for staple length, staple strength, resistance to compression and yield in alpacas are given for the ®rst time, whereas live weight, ¯eece weight and other ®ber character-istics were shown to have similar or higher values than those published for camelids in South America.
Acknowledgements
We are very grateful to Mr. R Dunick for shearing instruction, Mr. D Anderson for shearing the alpacas and to Dr G.H. Moore for animal management during this study. The Ministry of Agriculture and Fisheries of New Zealand funded the initial research on alpaca ®ber.
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