Applied Animal Behaviour Science, 23 (1989) 237-246 237 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

Grazing Behaviour of Llamas, Alpacas and Sheep in the Andes of Peru*

J.A. PFISTEW, F. SAN MARTIN 2, L. ROSALES 2, D.V. SISSON 3, E. FLORES 4 and F.C. BRYANT ~

' USDA-ARS, Poisonous Plant Research Laboratory, Logan, UT 84321 (U.S.A.) 2 Veterinary Institute for Tropical and High Altitude Research, San Marcos University, Lima (Peru) 3Department of Mathematics and Statistics, Utah State University, Logan, UT 84321 (U.S.A.) 4National Agricultural University, La Molina, Lima (Peru) '~Department o/Range and Wildlife Management, Texas Tech University, Lubbock, TX 79409 (U.S.A.)

(Accepted for publication 26 January 1989 )

ABSTRACT

Pfister, J.A., San Martin, F., Rosales, L., Sisson, D.V., Flores, E. and Bryant, F.C., 1989. Grazing behaviour of llamas, alpacas and sheep in the Andes of Peru. Appl. Anita. Behav. Sci., 23: 237- 246.

Llamas, alpacas and sheep graze jointly in many herds in the Andes. As foraging behaviour may be an important aspect of resource partitioning among camelids and sheep, activity budgets and feeding patterns during one wet and one dry season were quantified. We found that llamas gen- erally spent more time (P<0.05) at each feeding station than did alpacas and sheep. Bite rate differed (P < 0.05 ) among animal species with alpacas > llamas > sheep. Llamas and alpacas had greater (P<0.05) total grazing times than sheep. However, llamas divided their grazing time evenly among tall, coarse bunchgrasses and low-growing grasses, while alpacas and sheep spent the majority of their grazing time consuming low-growing grasses and/orbs. Camelids and sheep appear to occupy different foraging niches in the Andes. Llamas may be better adapted than alpacas and sheep to subsist on coarse forage in drier Andean regions as a consequence of their foraging behaviour.

INTRODUCTION

Llamas (Lama glama L.) and alpacas (L. paco L.) are domesticated mem- bers of the South American camelids, and are found primarily in the Andean mountains of Bolivia and southern Peru. Llamas and alpacas are important components of the agricultural economy in the Andes. Llamas are used mainly as pack animals and the meat is a dietary staple of the indigenous people.

*Technical article T-9-510 of the College of Agricultural Sciences, Texas Tech University.

0168-1591/89/$03.50 © 1989 Elsevier Science Publishers B.V.

238

Alpacas are raised primarily for fiber production for export and local use. Most llamas and alpacas in the Andes are grazed by traditional campesino pastor- alists in small flocks mixed with sheep.

Sheep (Ovis aries L. ) were introduced into South America during the Span- ish invasion. Numerically, sheep are the most important livestock species in the Andes.

Camelids have been presumed to be less selective grazers than sheep because of their larger body size (San Martin, 1987). The only research that has quan- tified the diets of llamas, and compared camelids and sheep is that of San Martin (1987). He found that sheep were more selective grazers than camelids, with llamas selecting coarse bunchgrasses particularly.

To our knowledge, no studies have compared the foraging behaviour of do- mesticated camelids and sheep. Feeding behaviour may be an important com- ponent of niche separation and resource partitioning of camelids and sheep in the Andes. The objectives of this study were: (1) to quantify and contrast the activity budgets and feeding patterns of llamas, alpacas and sheep; (2) to relate feeding behaviour to dietary selection by these species.

MATERIALS AND METHODS

Study site

The study was conducted at the Peruvian National Research Center for South American Camelids at La Raya (14 ° 30'S 71'W). The elevation of the valley floor at La Raya is 4070 m; the study was done in pastures on mountain slopes just above the valley floor. The vegetation was dominated by Festuca dolicho- phyUa Presl. and Calamagrostis vicunarum (Wedd) Pilger, which are both tall (15-60 cm) perennial bunchgrasses. Short plants (1-8 cm height) such as Muhlenbergia fastigiata Presl., a perennial rhizomatous grass, Poa canda- moana Pilger and several ephemeral forb species were typically found in the interspaces between bunchgrasses.

Climatically, the area is characterized by distinct wet and dry seasons. The wet season usually occurs from November to April and the dry season occurs from May to October. Little or no precipitation falls during the dry season; annual precipitation averages 956 mm. Droughts are common, often extending the dry season to 10 or 11 months of the year. During 1986, precipitation pat- terns were normal. Mean annual temperature at La Raya is 6.5 ° C, with much larger diurnal variation than seasonal fluctuation.

Behavioural observations

A uniform native pasture was divided into two 5-ha paddocks, and four fe- male adult animals of each species were placed into each paddock. The llamas,

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alpacas and sheep had mean weights of 90, 68 and 50 kg each, respectively. All 24 animals were marked to provide easy identification from the central point in the paddocks. The study was conducted during four periods in 1986: late March (wet season); late May (transition from wet to dry); early August (dry season ); November (transition from dry to wet). Animals were allowed to graze only during daylight hours and were placed in a corral at night following the local custom to prevent predation or theft. Animals were released to graze each day near daybreak (0700 h) and freely grazed their assigned paddock until about 1700 h.

Time spent per feeding station

Each animal was focally observed (Altmann, 1974 ) during each period, which entailed continuous observation until a certain number of observations were recorded. Using an electronic stopwatch over a 3-day period, 10 feeding sta- tions were quantified per animal during the morning and again during the afternoon feeding period. A feeding station was defined as the time an animal spent eating at a location without moving its front feet (Ruyle and Dwyer, 1985 ). Bites were also counted at each feeding station.

Means of time per feeding station (TFS) and bite rate were analyzed using analysis of variance. Paddocks were replicates, and differences between species were tested using the pasture by species error term. Repeated measurements were made on individual animals over the four periods. When main effects of species or periods were significant, the protected LSD procedure was used to compare means (Steel and Torrie, 1980).

Vegetation measurements were made concurrently with TFS observations. For each period, 10 feeding station events for each species, in each paddock, were selected at random, and the point where the animal was feeding was marked with a stake after the animal vacated the spot. A 1-m 2 plot was placed there and clipped to ground level. Clipped composite samples were oven dried at 60 ° C for standing crop data, then analyzed for crude protein using a macro- Kjeldahl technique (Harris, 1967). Standing crop and crude protein data for each period were compared using 90% confidence intervals.

Activity budgets

Scan samples (Altmann, 1974) were used to determine activity budgets for each species. The grazing animals were systematically (i.e. predetermined ran- dom order) scanned beginning at 0800 h each day for 3 consecutive days in each paddock. The observer changed to the next animal every minute, taking 12 min to scan the entire herd. For each observation, the observer noted the animal number, then counted from 1 to 5 and noted the activity of the animal at the count of 5. The observer continued in this fashion, with regular rest

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periods, until the animals were penned in the evening. A total of 3744 obser- vations were made on each species during the study. The percentage frequency for each behaviour category was calculated over the 3-day period during each month.

Behavioural categories were: (1) prehension - actively prehending forage - the vertical stratum the animal was prehending in was also noted as either Stratum 1 (0-10 cm) or Stratum 2 ( > 10 cm); (2) masticating recently pre- hended forage, usually with head up; (3) walking (not grazing) to or from bedding grounds, faecal depository sites, or water; (4) ruminating either stand- ing up or laying down; (5) resting (not ruminating) either standing up or laying down; (6) other, includes watering, social, sexual or eliminative activi- ties. Total grazing was the sum of grazing in Strata 1 and 2, plus masticating prehended forage.

The percentage of time spent in each category was calculated from the fre- quency data. Percentages were transformed using the arcsine transformation (Steel and Torrie, 1980) and analyzed using analysis of variance procedures. Paddocks were considered replicates and the pasture by species interaction was used to test for species differences. Repeated measurements were made on each animal during March, May, August and November. Means are presented using original untransformed data.

RESULTS

Forage availability and quality

More forage was available ( P < 0.1 ) during March and May than in August and November (Table 1 ). These results are typical for Andean pastures, where large accumulations of plant biomass occur during the wet season, and under moderate stocking rates are only partially depleted during the dry season (J.A. Pfister, unpublished data, 1986). The forage was highest in crude protein con- tent during March and November, the two wettest months of the four exam-

T A B L E 1

Mean s tanding crop and crude prote in conten t of forage during four periods in the Andes of Peru

Period S tanding crop Crude prote in (kg ha -1 ) (% dry ma t t e r )

March 3411" 8.7" May 2972 a 5.5 a'b August 1780 b 4.2 b November 1286 b 9.1 a

a'bMeans in the same column wi th the same letters are not significantly different ( P > 0.1 ).

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ined. Generally, early rains begin the wet season in November, and forage growth is then initiated. January-March is when the largest total amount of wet season precipitation falls at LaRaya.

Time spent per feeding station

There were period differences (P < 0.05) in TFS, and a period × species in- teraction (P<0.05) (Fig. 1). Llamas and alpacas differed (P<0.05) during May and August, and camelids had greater TFS ( P < 0.05) than sheep during November (early wet season).

Period differences (P<0.05) were also found in bite rate (Fig. 2), and a

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periodx species interaction was detected ( P < 0.05). During the wet season (March), and transition period from wet to dry (May), there were large dif- ferences (P < 0.05) between all species. However, during the dry season (Au- gust) sheep were not different (P> 0.05) from llamas, and alpacas had higher bite rates (P<0.05). During the transition period into the wet season (No- vember), llamas had lower bite rates ( P < 0.05) than alpacas and sheep.

Activity budgets

There was a significant period effect for each variable (P<0.05). Pe- r iodx species interactions ( P < 0.05 ) were found for each variable except mas- ticating, total grazing time and other activities (P> 0.1 ). During the wet sea- son (March), llamas spent the majority of their time prehending in Stratum 2, while sheep and alpacas were prehending near ground level in Stratum 1. During the dry season (August) all three species were prehending most of the time in the lower Stratum 1 (Table 2). Llamas and alpacas had greater (P< 0.05) total grazing times (76 and 77%, respectively) than sheep (60%, Table 2 ). Camelids spent 4-5% of their time masticating while foraging, com- pared with 2% for sheep (P>0.05). Sheep spent about twice as much time resting as did camelids during August and November. There was no species difference for time spent ruminating (P > 0.05 ), although there was a trend for sheep to spend more time ruminating than camelids. An unknown amount of rumination undoubtedly occurred at night.

DISCUSSION

Behavioural results generally were consistent with the observations of San Martin (1987) that camelids and sheep occupy different foraging niches in the Andes. San Martin (1987) reported that alpacas were intermediate between sheep and llamas in many diet selection characteristics depending upon the season of the year and forage conditions. In this study, alpacas and llamas had similar (P > 0.05 ) feeding patterns (TFS) during the wetter months of March and November, and diverged greatly from sheep during the November period (P< 0.05). Alpacas and sheep had similar (P> 0.05) grazing patterns during the drier months of May and August. All species increased TFS (P<0.05) from the wet (March) to the dry (August) season.

Senft et al. ( 1987 ) indicated that feeding station times may reflect the rich- ness of the foraging environment, with animals moving slower (i.e. longer TFS) as forage quantity increases. This study did not support such a view (Fig. 1 ). Generally, feeding station times were shorter when forage availability was greater. Camelids maintained long feeding stations during the transition into the wet season (November), when sheep greatly reduced TFS. Sheep were presumably responding to the initiation of green forage growth during this

244

period. Pfister et al. (1988) noted that sheep but not goats, reduced TFS when consuming young forbs at the beginning of the wet season in Brazil.

During the wetter months, sheep and alpacas spent about 50-60% of their t ime grazing on plants near ground level, compared with ~ 20% for llamas. San Mart in (1987) found that llamas selected diets with mostly tall grasses, while alpacas selected both tall and short grasses and forbs, and sheep ate mainly short grasses and forbs during the wet season (Table 3 ).

Camelids and sheep were similar in spending most of their t ime during the dry months grazing in the lower forage stratum. As noted by San Martin (1987), llama, alpaca and sheep diets during the dry season consisted mostly of short grasses. Alpacas and sheep, however, selected larger amounts of forbs than did llamas (Table 3).

Both camelids and sheep adjusted bite rate and TFS seasonally as forage conditions changed. Changes by camelids tended to parallel one another, while sheep made radically different adjustments during the transition period into the wet season. This increase in bite rate and decrease in TFS indicates the more selective nature of sheep compared with camelids. San Mart in (1987) noted that sheep diets were least similar to the forage standing crop.

The basic processes of forage digestion in camelids are similar to those in true ruminants, like sheep, but there are some important differences that may influence selectivity. For example, s tomach morphology differs between ca- melids and true ruminants (Vallenas, 1965). Camelids have lower forage in- takes (Reiner et al., 1987 ), slower rates of particulate passage and longer rum- inal retention times compared with those for sheep (San Martin, 1987 ). These

TABLE 3

Dietary composition (%) of llama, alpaca and sheep during the dry and wet season in the Andes of Peru a

Plant group Dry season (July) Wet season (January)

Llama Alpaca Sheep L l a m a Alpaca Sheep

Tall grasses b 38 24 17 45 28 20 Short grasses c 51 38 43 42 29 66 Graminoids c 6 2 3 5 1 1 Forbs c 4 35 35 7 42 13 Similarity index (%)d 39 31 26 53 35 27

aAdapted from San Martin (1987). bCoarse bunchgrasses generally 0.5-1.5 m in height. CGenerally, annual and perennial plants from 5 to 30 cm in height with numerous mat-forming species < 10 cm in height. dSimilarity between diets selected by grazing animals and the amount of forage available. Smaller similarity indices indicate that grazing animals are more selective in dietary composition.

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characteristics allow for more complete digestion of coarse forages (Van Soest, 1982).

Alpacas and llamas always had similar total grazing times that were greater than for sheep, yet alpacas spent more of this time grazing in lower strata than did llamas. When forage conditions were poorest during the dry season, llamas and alpacas had nearly identical activity budgets and intakes (San Martin, 1987), but alpaca diets were of higher quality than those of llamas (San Mar- tin, 1987).

Llamas appear to be better adapted than alpacas to subsist on the lower quality forage found in the drier regions of the Andes (San Martin and Bryant, 1989). Llamas used the coarse bunchgrasses in the higher vertical stratum more extensively. They also spent more time at each feeding site, had a lower bite rate and selected lower quality diets (San Martin, 1987) than alpacas indicating that llamas were taking more time to consume coarser material. Llamas are apparently able to thrive on such coarse forage because of physio- logical adaptations that compensate for poorer quality diets (San Martin, 1987).

This study and that of San Martin (1987) suggest that management of Am dean rangelands can exploit species-specific differences in foraging behaviour. Traditionally, both fire and grazing by horses have been used to reduce the biomass of coarse bunchgrasses. Llamas, however, have a longer history of coevolution with Andean rangelands than do European livestock (Wheeler, 1988). Consequently, we recommend that prescribed burning be used with cau- tion in many areas because of low amounts of litter and highly erodible soils. Llamas appear to be ideal animals to utilize coarse bunchgrasses, thus allowing more desirable plant species to grow in the plant communities.

ACKNOWLEDGEMENTS

This research was funded under the auspices of the USAID Small Ruminant Collaborative Research Program, Grant DSAN/XII-G-0049, in conjunction with Instituto Veterinario de Investigacion Tropicales y Altura, San Marcos University, Lima, Peru. We are grateful for the assistance rendered by Ing. Ramiro Farfan and Ing. Timoteo Huisa during the study.

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