Ž .Small Ruminant Research 29 1998 295–301

Voluntary intake and digestibility of forages with differentž /nutritional quality in alpacas Lama pacos

Alejandro Lopez a,), Jose Maiztegui b,1, Raul Cabrera c,2´ ´ ´a UniÕersidad de Chile, Facultad de Ciencias Veterinarias y Pecuarias, Casilla 2, Santiago 15, Chile

b UniÕersidad Nacional del Litoral, Facultad de Agronomıa y Veterinaria, R.P. Luıs Kreder 2805, 3080 Esperanza, Santa Fe, Argentina´ ´ ´c ( )UniÕersidad de Chile, Instituto de Nutricion y Tecnologıa de los Alimentos INTA , Casilla 138, Santiago 11, Chile´ ´

Accepted 21 October 1997

Abstract

Ž .There is an increasing interest in the introduction of domestic South American Camelids SAC to semi-arid andŽ . Ž .non-plateau arid lands located at the Central South 35–428Sr71–748W and Magallanic 49–558Sr69–758W regions of

Ž .Chile. The climatic conditions of these zones differ from the ones at the Andean plateau 17–218Sr68–708W , though theyhave in common, a low availability of poor quality forage, greatest in dry seasons. The objective of this study was todetermine the apparent digestibility coefficients and voluntary intake of four forages from a location at the V Region of

Ž . ŽChile 33820 Sr71830 W , with eight adult alpacas in a replicated 4=4 Latin Square experiment. The forages commercial. Ž . Ž .hays, stage of maturity not established were the following: 1 Clover mostly Red clover plus Italian ryegrass and Fescue ;

Ž . Ž . Ž . Ž2 Ryegrass mostly Italian ryegrass plus Fescue and weeds ; 3 Wheat straw mostly Wheat straw plus other herbs and. Ž . Ž . 0.75weeds and 4 Fescue only Fescue . The voluntary intake of dry matter and organic matter per kg BW was greater

Ž . 0.75P-0.05 in ryegrass and fescue than in clover and wheat straw, ranging from 39.9 to 63.1 grkg for dry matter and36.5 to 57.1 grkg0.75 for organic matter. The results indicate that the intake of dry matter and organic matter was dependent

Ž .on forage quality. The digestibility of dry matter ranged between 48.4 and 55.9% P-0.05 . There were no significantŽ . Ž .differences P)0.05 between feeds in respect to organic matter digestibility 55.0 to 59.7% in spite of differences in the

Ž . Ž . Ž .nutrient composition. The digestibility of crude protein was higher P-0.05 in clover 63.0% and ryegrass 55.5% thanŽ . Ž .in fescue 34.6% . The wheat straw had a negative protein digestibility coefficient y42.0% . The digestibility of neutral

Ž .detergent fiber and hemicellulose was greater P-0.05 for wheat straw and fescue than for clover which had the highestŽ . Ž .lignin content. The digestibility of acid detergent fiber 43.2 to 49.2% and cellulose 57.9 to 64.8% was not different

Ž .P)0.05 between forages. The digestibility of cell wall was high considering the quality of the forages used in this trialand is in agreement with other studies where SAC showed also a great ability to digest low quality forages. q 1998 ElsevierScience B.V. All rights reserved.

Keywords: Camelids; Alpaca; Digestibility

) Corresponding author. Tel. q56-2-678-5554; fax: q56-2-541-6840.

1 Tel.: q54-496-20-639; fax: q54-496-22-733.2 Tel.: q56-2-678-1425; fax: q56-2-221-4030.

1. Introduction

Ž .Among the South American Camelids SAC , thealpacas and llamas are domesticated species. The

00921-4488r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved.Ž .PII S0921-4488 97 00135-1

( )A. Lopez et al.rSmall Ruminant Research 29 1998 295–301´296

breeding of alpacas is a main source of income forthe Aymaras communities living at the Andean

Ž .plateau 17–218Sr68–708W . Their native foragesare sparse and low quality, very high in cell wallsand deficient in protein. The consequence is thatanimals often suffer from malnutrition, especiallyduring the dry season with negative effects on the

Žreproductive performance fertility rates of 40 to.60%; De Carolis, 1987 and high mortality of suck-

Ž .ling alpaca calves up to 30%; Raggi et al., 1995 .All these factors, together with low body weight

Ž .gains during the first year of life San Martın, 1991 ,´contributes to slow population growth.

In general, SAC show greater ability than otherŽruminants to digest fibrous forages Hintz et al.,

1973; San Martın et al., 1984; Warmington et al.,´.1989; Valenza et al., 1991; Dulphy et al., 1994 .

This can be attributed to several factors, such as amore efficient nitrogen recycling, due to a lower

Žrenal excretion Hinderer and Engelhardt, 1975; En-.gelhardt et al., 1988; San Martın, 1991 , and a higher´

Žruminal retention time for the solid phase Clemensand Stevens, 1980; Heller et al., 1986; Engelhardtand Holler, 1987; San Martın, 1991; Dulphy et al.,´

.1994 , which favors cell walls degradation via agreater exposure time to microorganisms. Anotherfactor is the pH of the ruminal contents, which inSAC, is closer to neutrality favoring so cellulolytic

Ž .digestion Hoover, 1986; Van Soest, 1994 . This isŽdue to bicarbonate secretion in C-1 and C-2 Cum-

mings et al., 1972; Eckerlin and Stevens, 1973;.Vallenas, 1991 . Furthermore, it has been reported

that Camelids show higher concentrations of volatileŽ .fatty acids VFA in C-1 and C-2 as compared to

Žother ruminants Engelhardt et al., 1988; San Martın,´.1991 , which could be explained by the higher pH

that neutralizes the VFA, keeping them as ions whichare more slowly absorbed. Probably, all these factorscontribute to the greater stability of the availableVFA in SAC, which they use as an energy source,and also results in a greater utilization of medium tolow quality forages.

Previous studies indicated that further research onthe SAC digestive system and nutritional aspects isneeded. There is an increasing interest of the Chileangovernment and private enterprises in producing do-mestic SAC in semiarid and arid areas other than theAndean plateau. This trial was set up to obtain the

apparent digestibility of four forages grown in theCentral zone and selected to be representative ofthose actually available to SAC in the country.

2. Material and methods

A trial was run during the summer time at theŽ .Central Region of Chile 33830 Sr70830 W . Eight

male alpacas of the Huacaya breed were selected forŽ . Ža similar age about 4 years and weight 56.0"8.0

.kg . The animals were kept in individual pensequipped with feeders and water pails.

The forages were commercial hays, with a stageof maturity not established and were the following:Ž . Ž1 Clover 52% Trifolium pratense, plus Lolium

. Ž .multiflorum, Festuca arundinacea and others ; 2ŽRyegrass 68% Lolium multiflorum, plus Festuca

. Ž . Žarundinacea and others ; 3 Wheat straw 70%Triticum aestiÕum plus Bromus hordaceus and oth-

. Ž . Ž .ers and 4 Fescue 100% Festuca arundinacea .The study was based on a 4=4 Latin Square

assay with two replicates and eight digestibility val-ues per feed. Data were obtained by fecal totalcollection using harness—collection bag sets. Each

Žof the four experimental phases last 14 days 9 days.adjustment and 5 days collection periods . The for-

Ž .ages were offered as it was not chopped , since thisis the way they are offered in practice. When thecollection period begun, the feed offered was re-duced to 90% of the voluntary intake recorded dur-ing the last 5 days of the adjustment period. Feces

Žwere collected daily, weighed and sampled 20% of.the total output , dry matter was determined and

feces stored at y208C for later analysis. Five dailysamples from each animal in the period were thawed,mixed into a pool and dried. A pooled sample ofeach feed was taken for each collection period,which granted four samples per feed. The analysisperformed to feces and forages were dry matterŽ . Ž . Ž .DM , organic matter OM , crude protein CP and

Ž . Ž .ether extract EE according to A.O.A.C. 1995 andcell walls by the methods of Goering and Van SoestŽ . Ž .1970 for neutral detergent fiber NDF , acid deter-

Ž . Ž .gent fiber ADF , hemicellulose HEMI , celluloseŽ . Ž .CELLU and lignin LIG . The data were submittedto Analysis of Variance for Latin square designs,

Ž .Tukey’s test P-0.05 for multiple comparisons

( )A. Lopez et al.rSmall Ruminant Research 29 1998 295–301´ 297

among means and a Correlation Analysis amongŽ .variables Sokal and Rohlf, 1981 .

3. Results and discussion

The forages used in the trial, in spite of theŽ .differences found between them Table 1 , were in

most cases of low quality with a high content of cellŽ .walls NDF up to 80% in wheat straw and a high

Ž .lignin content 11% in clover . Protein content variedfrom 2.2 to 10.9% and was below 7.4%, the mini-mum suitable level for maintenance of adult animalŽ .Lopez and Raggi, 1992 in fescue and wheat straw.´

Ž .The intake of DM and OM Table 2 followed thesame trend and were affected by forage quality, since

Žthe intake was higher for ryegrass and fescue P-.0.05 than for wheat straw and clover, which exhib-

ited the highest cell wall and lignin contents respec-tively. This explains the positive correlation between

Ž .DMI and DMD rs0.52 and the negative oneŽ .rsy0.53 between DMI and LIGrNDF ratio of

Ž .forages Table 3 , since wheat straw and clover werehighest in lignin. Dry matter intake of straw in the

Ž 0.75 y1.present trial 39.9 g kg d was similar to theŽ .one obtained by Cordesse et al. 1992 , with llamas

Ž 0.75 y1. Ž .36.5 g kg d and by Dulphy et al. 1994 , inŽllamas fed on a wheat strawrsoybean cake diet 42.2

0.75 y1.g kg d . Intake of the wheat straw diet was

Table 1Average nutritional composition of forages on dry matter basis

Nutrients Clover Ryegrass Wheat straw Fescue SEM

DM% 91.1 90.7 91.8 91.5 0.59a b b bOM% 94.3 90.5 91.6 90.9 0.48a a c bCP% 10.9 9.7 2.2 5.5 0.64ab a b bEE% 1.8 2.3 1.4 1.4 0.13c c a bNDF% 62.3 61.4 79.9 68.3 1.29b c a bADF% 44.9 35.6 53.2 43.2 1.07b a a aHEMI% 17.4 25.8 26.7 25.1 0.83b c a bCELLU% 32.4 27.1 38.6 32.8 0.91a d b cLIG% 11.1 5.2 9.1 6.6 0.29

DM: dry matter; OM: organic matter; CP: crude protein; EE: etherextract; NDF: neutral detergent fiber; ADF: acid detergent fiber;HEMI: hemicellulose; CELLU: cellulose; LIG: lignin.SEM: standard error of means.a,b,c,d Different letters in the same line, mean significant differ-

Ž .ences between forages P -0.05 .

Table 2Average intake and apparent digestibility of different forages inalpacas

Clover Ryegrass Wheat straw Fescue SEM0 .75 y 1( )Forage intake g kg d

b a b aDMI 40.1 63.1 39.9 56.9 4.55b a b aOMI 37.8 57.1 36.5 51.7 4.50

( )Digestion coefficients %ab a b aDM 54.4 55.3 48.4 55.9 2.19

OM 58.5 59.2 55.0 59.7 2.40a a c bCP 63.0 55.5 y42.0 34.6 4.70a ab b abEE 60.7 57.3 46.8 49.7 4.15b ab a aNDF 46.9 50.9 54.2 54.3 2.45

ADF 45.3 43.2 49.2 49.1 2.57b a a aHEMI 51.0 61.5 64.0 63.0 2.95

CELLU 58.0 58.2 64.8 61.4 2.73

DMI: dry matter intake; OMI: organic matter intake; OM: organicmatter; CP: crude protein; EE: ether extract; NDF: neutral deter-gent fiber; ADF: acid detergent fiber; HEMI: hemicellulose;CELLU: cellulose; LIG: lignin.SEM: standard error of means.a,b,c Different letters in the same line, mean significant differences

Ž .between forages P -0.05 .

likely depressed by the low CP, since San Martın´Ž .and Bryant 1989a demonstrated that intake of OM

increased in llamas and sheep as CP in the diet wasincreased from 7 to 15%. The low CP also made thediet limiting in nitrogen for microbial growth de-

Žpressing digestibility of cellulose Garnsworthy and.Cole, 1990 . This negative effect though was not

present in this trial, since cellulose digestion inwheat straw was similar to other forages. DM intakeof alpacas on a fescue grassland was 42.4 g kg0.75

y1 Ž .d San Martın, 1989 , less than in the present trial´Ž 0.75 y1.56.9 g kg d . Lower DM intakes were ob-

Ž .served by Warmington et al. 1989 in llama=

guanaco crossbred animals on a mixed redŽ 0.75 y1.cloverrryegrass forage 39.1 g kg d . On theŽ .other hand, San Martın 1989 observed a DM intake´

of 41.2 to 59.4 g kg0.75 dy1 and an OM intake of44.3 to 50.5 g kg0.75 dy1 in grazing alpacas on amixed pasture of fescue and other grasses.

ŽSeveral studies San Martın and Bryant, 1989a;´˚ .Graham and Aman, 1991; Van Soest, 1994 demon-

strate that the intake of DM is negatively correlatedwith rumen retention time and positively correlatedwith ruminal volume and feed digestibility. The dif-

( )A. Lopez et al.rSmall Ruminant Research 29 1998 295–301´298

Table 3Correlation coefficients for some nutritional variablesa

Ž .DMI DMD NDFD ADFD N-ADFD HEMID CELUD HEMI LIGrNDF

DMI 1.00b0.0000

DMD 0.52 1.000.0024 0.0000

NDFD 0.33 0.83 1.000.0627 0.0001 0.0000

ADFD 0.24 0.82 0.97 1.000.1834 0.0001 0.0001 0.0000

Ž .N-ADFD 0.36 0.06 0.18 y0.08 1.000.0429 0.7374 0.3207 0.6526 0.0000

HEMID 0.32 0.71 0.93 0.82 0.49 1.000.0742 0.0001 0.0001 0.0001 0.0044 0.0000

CELUD 0.10 0.71 0.92 0.89 0.15 0.89 1.000.5861 0.0001 0.0001 0.0001 0.4125 0.0001 0.0000

HEMI 0.29 0.20 0.56 0.39 0.65 0.70 0.47 1.000.1138 0.2695 0.0009 0.0263 0.0001 0.0001 0.0066 0.0000

LIGrNDF y0.53 y0.22 y0.45 y0.25 y0.78 y0.62 y0.29 y0.83 1.000.0018 0.2263 0.0098 0.1676 0.0001 0.0002 0.1074 0.0001 0.0000

aAll forages included, ns32.bP value for correlation.DMI: dry matter intake; DMD: dry matter digestibility; NDFD: neutral detergent fiber digestibility; ADFD: acid detergent fiber digestibility;Ž .N-ADFD : difference between NDF and ADF digestibility; HEMID: hemicellulose digestibility; CELUD: Cellulose digestibility; HEMI:hemicellulose content of forages; LIGrNDF: ligninrNDF ratio of forages.

ferences observed in DM and OM intakes, could bedue to variations in retention time.

The digestibility of DM and OM show similartrends although the differences reached significance

Ž .only for DM Table 2 . DM digestibility was bestŽ . Ž .P-0.05 in fescue 55.9% and least in wheat

Ž .straw 48.4% . Clover and ryegrass were also welldigested, 54.4 and 55.3%, respectively, which ishigher than 48% obtained by Warmington et al.Ž .1989 , for llamas fed on a cloverrryegrass mixture.

Ž .Cordesse et al. 1992 observed 55% OM digestibil-ity in llamas fed on wheat straw, similar to that

Ž .obtained in this study. Similar results 52.4% wereŽ .reported by Dulphy et al. 1994 in llamas receiving

a mixture of wheat straw and soybean cake, withŽ .values for ovines somehow lower 50.2% . When

good quality forages were fed, such as alfalfa hay,values for DM digestibility in alpacas ranged from

Ž .63.5 to 65.1% Lopez et al., 1996 , and up to 71.5%´Ž .in llamas and 63.8% in ovines Hintz et al., 1973 .

This is in agreement with many others authors whohave found that the DM and OM digestibility is

Žhigher in SAC than in ovines San Martın, 1989; San´

Martın and Bryant, 1989a; Warmington et al., 1989;´San Martın, 1991; Valenza et al., 1991; Cordesse et´

.al., 1992; Dulphy et al., 1994 .Ž .The protein digestibility CPD was related to the

Ž .CP in forage, being highest in clover 63.0% andŽ .lowest in wheat straw y42.0% , which in the latter

means that the ingested CP was below the mainte-nance requirement. Ryegrass and fescue showed in-termediate values. Very few values concerning CPdigestibility in SAC are found in the literature. San

Ž .Martın and Bryant 1989b observed a protein di-´gestibility of 60% in alpacas and 61.9% in sheep, indiets with 10.5% CP. In diets with less than 7.5%CP, the digestibility declined to 42.1% in alpacas

Ž .and to 36.1% in sheep. Lopez et al. 1996 found´digestibility figures of 71.3 to 76.1% for alfalfa with

Ž .19.0 to 21.3% CP in alpacas. Cordesse et al. 1992 ,in feeding alfalfa hay or urea treated wheat straw tollamas and sheep, found no difference in CP di-gestibility between species, whereas Warmington et

Ž .al. 1989 , for ryegrass straw, found a negative nitro-gen balance in sheep and llamas, although the lattershowed a lower urinary nitrogen loss.

( )A. Lopez et al.rSmall Ruminant Research 29 1998 295–301´ 299

Ž .The EE digestibility EED showed higher valuesŽ . Ž .P-0.05 for clover 60.7% than for wheat strawŽ . Ž . Ž .46.8% , fescue 49.7% and ryegrass 57.3% beingintermediate. Similar results were found by Lopez et´

Ž . Ž .al. 1996 for alpacas fed alfalfa hay 46.2 to 68.9% .Ž . ŽDigestibility of NDF NDFD was higher P-

.0.05 for fescue and wheat straw than for clover,with ryegrass being intermediate and had a negative

Žcorrelation with LIGrNDF ratio of forages rs. Ž .y0.45 but positive rs0.56 with hemicellulose

Žcontent. The values obtained for NDFD 46.9 to.54.3% were similar to those reported by Lopez et al.´

Ž .1995 for alpacas fed forages of comparable qualityŽ .40.5 to 52.3% and also similar to the ones reported

Ž .by Lopez et al. 1996 for alfalfa hay of different´Ž . Ž .qualities 44.3 to 54.6% . Valenza et al. 1991 , in

feeding oat hay, observed that the NDF digestibilitywas 10 and 8 percentage units higher in alpacas andllamas, respectively as compared to sheep, but weresimilar when a mixture of oat and quinua stubblewas fed. With other medium quality forages, San

Ž .Martın and Bryant 1989a found that the digestibil-´ity of NDF was 11.0, 7.0 and 17.0 percentage unitshigher in llamas than in sheep, in diets with 68, 58

Ž .and 42% NDF, respectively. Hintz et al. 1973 , inalfalfa hay, reported that NDF digestibility was69.4% in llamas, which was 11 percentage unitshigher than in sheep. Nevertheless, in some compara-tive studies, no differences have been found betweenllamas and sheep, or a slight superiority in SACŽ .Warmington et al., 1989; Dulphy et al., 1994 .

Ž .The ADF digestibility ADFD was very similarŽ .for all forages P)0.05 , ranging from 43.2 to

49.2%. For all forages, the difference in digestibilityŽ .between NDF and ADF N-ADFD was positively

Ž .correlated rs0.65 to the hemicellulose content ofthe feed. The ADF digestibility figures were some-what higher than the ones reported by Lopez et al.´Ž .1995 with alpacas receiving forages of similar

Ž .quality 37.0 to 46.9% , while the values found byŽ .Lopez et al. 1996 for alfalfa hay of different quali-´

Ž .ties ranged from 49.1 to 54.5%. Hintz et al. 1973Ž .and Carmean et al. 1992 found values of about

61.0% for ADFD in llamas receiving alfalfa, andonly 50.5% in sheep.

Ž .The hemicellulose digestibility HEMID wasŽ . Ž .lower P-0.05 for clover 51.0% as compared

Ž .with the other forages 61.5 to 64.0% . The correla-

tion found between hemicellulose digestibility andŽLIGrNDF ratio was negative as expected rs

.y0.62 . The hemicellulose digestibility in this trialŽ .was similar to the works of Lopez et al. 1995 for´

Ž .forages of similar quality in alpacas 49.6–59.7%Ž .but lower than reported by Bas et al. 1992 for

Ž .different by-products 57.7–71.7% . Hemicellulosedigestibility in alfalfa varied from 24.7 to 53.4% in

Ž .alpacas Lopez et al., 1996 , and up to 59.8% in´Ž .llamas Warmington et al., 1989 . This capability of

SAC to digest hemicellulose is very important undernative conditions, since they are very selective for

Žgrasses Reiner et al., 1987; Bonino and Pelliza.Sbriller, 1991 , which are 20 to 30% hemicellulose,

Žwhereas alfalfa is only 8–12% Wilson and Mertens,.1995 .

Ž .Cellulose digestibility CELD was also high butsimilar for all four forages ranging from 58.0 to

Ž .64.8% P)0.05 . These values surpass those re-Ž .ported by Lopez et al. 1995 , which varied from´

48.5 to 57.4% for comparable forages, and similar toŽ .those of the works of Lopez et al. 1996 for alfalfa´

Ž .55.5–64.7% .Table 3 shows additionally, a high positive corre-

lation between the digestibility of DM and that ofmost cell wall fractions. There is also a positivecorrelation between the digestibility of all cell wallfractions, bearing a negative r value for the relation-ship nutrients digestibility vs. LIGrNDF ratio offorages.

All these results prove that SAC behave like trueruminants from the nutritional standpoint and agreewith most of the literature, showing their great abil-ity to digest low quality forages.

4. Conclusions

The feed intake in alpacas was clearly related tothe forage quality, being negatively correlated withlignin content of forages, and positively correlatedwith its digestibility.

Very low quality forages like wheat straw, show ahigh NDF and ADF digestibility, in spite of a nega-tive protein digestibility as a result of a low nitrogenintake.

The digestibility of the different nutritive frac-tions, proves the great adaptive capacity of the al-

( )A. Lopez et al.rSmall Ruminant Research 29 1998 295–301´300

paca and shows its special advantage when fed withpoor quality forages.

More research is needed on nutritional values offorages of different quality to develop sustainableproductive systems for alpacas.

Acknowledgements

The authors acknowledge Ernesto Haardt, formerprofessor, University of Chile, for his invaluableguidance and suggestions. This research was sup-ported by Grant No. 1940 253, FONDECYT, Chile.

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